Radiology: Medical School Crash Course

Radiology

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TABLE OF CONTENTS Preface........................................................................................................ 1 Chapter One: Plain Film X-rays ................................................................... 5 Basics of Plain Films ........................................................................................................ 5 What are X-rays? ............................................................................................................. 6 Risks of X-ray Exposure .................................................................................................. 6 Skull Series Films ............................................................................................................. 8 Cervical Spine Films ....................................................................................................... 11 Lumbar Spine Films....................................................................................................... 13 Chest X-ray..................................................................................................................... 14 Abdominal Films ............................................................................................................ 16 Shoulder Films ................................................................................................................17 Elbow Plain Films .......................................................................................................... 21 Wrist and Hand X-Rays ................................................................................................. 24 Knee X-rays .................................................................................................................... 31 Ankle X-ray .................................................................................................................... 34 Key Takeaways ............................................................................................................... 38 Quiz ................................................................................................................................ 39 Chapter Two: Fluoroscopy and Radiocontrast Studies .............................. 42 Fluoroscopy Basics......................................................................................................... 42 Types of IV Contrast ...................................................................................................... 46 Iodine-Based Contrasts ................................................................................................. 48 Lanthanide-based Contrast Agents ............................................................................... 51

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Gold Nanoparticle Contrast Agents ............................................................................... 51 Other Metallic Contrast Agents ..................................................................................... 52 Xenon Gas as a Contrast Medium ................................................................................. 52 Side Effects of Contrast Studies in Radiology ............................................................... 53 Key Takeaways ............................................................................................................... 56 Quiz ................................................................................................................................ 57 Chapter Three: Principles and Practice of Ultrasound ................................................. 61 How Ultrasound Works ................................................................................................. 61 Uses of Ultrasound......................................................................................................... 64 Ultrasound in Medicine ................................................................................................. 68 Contrast Ultrasonography ..............................................................................................71 Molecular Ultrasonography ............................................................................................71 Key Takeaways ............................................................................................................... 73 Quiz ................................................................................................................................ 74 Chapter Four: Computed Tomography Basics ........................................... 77 What is Computed Tomography? .................................................................................. 77 Artifacts in CT Scans ...................................................................................................... 79 Commuted Tomography in Medicine............................................................................80 CT of the Head ............................................................................................................... 82 Helical Chest CT ............................................................................................................. 83 High Resolution CT Scan of the Chest........................................................................... 83 CT Angiography ............................................................................................................. 84 Abdominal and Pelvic CT Scanning .............................................................................. 85 PET Scanning ................................................................................................................. 86

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SPECT Scanning ............................................................................................................ 88 Key Takeaways ............................................................................................................... 90 Quiz ................................................................................................................................ 91 Chapter Five: Magnetic Resonance Imaging Basics ................................... 94 Science of MRI ............................................................................................................... 94 Uses of MRI in Medicine ............................................................................................... 98 Functional MRI Scanning ............................................................................................ 100 Key Takeaways ..............................................................................................................101 Quiz .............................................................................................................................. 102 Chapter Six: Specialized Gastrointestinal X-Rays .................................... 106 Upper Gastrointestinal Series...................................................................................... 106 Barium Enema ............................................................................................................. 109 Motility Testing ............................................................................................................. 111 Hepatobiliary Imaging .................................................................................................. 112 CT Colonography .......................................................................................................... 113 Key Takeaways .............................................................................................................. 115 Quiz ............................................................................................................................... 116 Chapter Seven: Breast Imaging ................................................................ 119 Mammography .............................................................................................................. 119 The Mammogram Procedure ........................................................................................ 121 Positron Emission Mammography .............................................................................. 123 Scintimammography ................................................................................................... 123 MRI of the Breast ......................................................................................................... 124 Stereotactic Breast Biopsies......................................................................................... 125

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Key Takeaways ..............................................................................................................127 Quiz .............................................................................................................................. 128 Chapter Eight: Coronary Imaging ........................................................... 132 Coronary Angiography ................................................................................................. 132 Hemodynamic Assessment in Coronary Angiography ............................................... 136 Coronary CT Angiography ........................................................................................... 136 Calcium Scoring ........................................................................................................... 138 Echocardiography ........................................................................................................ 138 Key Takeaways ............................................................................................................. 143 Quiz .............................................................................................................................. 144 Chapter Nine: Cardiovascular Imaging .................................................... 147 Peripheral Vascular Disease Imaging .......................................................................... 147 Evaluation of Lower Extremity Deep Vein Thrombosis ............................................. 150 Carotid Imaging ........................................................................................................... 152 Aortic Aneurysm Imaging ............................................................................................ 154 Key Takeaways ............................................................................................................. 156 Quiz ...............................................................................................................................157 Chapter Ten: Obstetrical Imaging ............................................................ 161 Basic Obstetric Ultrasound ........................................................................................... 161 Doppler Imaging in Pregnancy .................................................................................... 168 Biophysical Profile Evaluations ................................................................................... 168 Key Takeaways .............................................................................................................. 171 Quiz ...............................................................................................................................172 Chapter Eleven: Gynecological Imaging ................................................... 176

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Ultrasound Imaging ..................................................................................................... 176 Hysterosalpingogram................................................................................................... 178 Key Takeaways ............................................................................................................. 182 Quiz .............................................................................................................................. 183 Chapter Twelve: Neurological Imaging ....................................................187 Brain Imaging .............................................................................................................. 187 MRI for Multiple Sclerosis ........................................................................................... 189 Evaluation of Cerebral Aneurysm ................................................................................ 191 Contrast Studies of the Spinal Column ....................................................................... 194 Evaluation of Spinal Stenosis ...................................................................................... 194 Ultrasound in Neuroimaging ....................................................................................... 195 Key Takeaways ............................................................................................................. 196 Quiz .............................................................................................................................. 197 Chapter Thirteen: Urinary Tract Imaging................................................ 201 Renal and Bladder Imaging ......................................................................................... 201 Vesicoureteral Reflux Imaging .................................................................................... 205 Renal Artery Stenosis Imaging ....................................................................................206 Prostate Imaging ..........................................................................................................206 Adrenal Imaging .......................................................................................................... 207 Nephrocalcinosis Imaging .......................................................................................... 208 Key Takeaways ............................................................................................................. 210 Quiz ............................................................................................................................... 211 Chapter Fourteen: Specialized Radiology of the Musculoskeletal System .215 Arthrogram .................................................................................................................. 215

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Imaging Avascular Necrosis of the Hip ....................................................................... 216 MRI of the Elbow Joints ...............................................................................................217 Bone Density Imaging.................................................................................................. 219 Bone Metastasis Imaging ............................................................................................. 221 Key Takeaways ............................................................................................................. 224 Quiz .............................................................................................................................. 225 Chapter Fifteen: Nuclear Medicine Techniques ....................................... 229 Thyroid Scan ................................................................................................................ 229 Gastric Emptying Study ............................................................................................... 231 Bone Scanning ............................................................................................................. 232 Ventilation-Perfusion Scan .......................................................................................... 233 Key Takeaways ............................................................................................................. 234 Quiz .............................................................................................................................. 235 Summary ................................................................................................ 239 Course Questions and Answers ............................................................... 243

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PREFACE This course introduces the healthcare practitioner to the different areas involved in the study of radiology. Over the last several decades, radiology has come from the diagnostics involved in plain film x-rays and fluoroscopy to many more modern techniques, such as ultrasound, computed tomography scanning or CT scanning, and magnetic resonance imaging or MRI. Radiology has also advanced from diagnostic studies only to interventional radiology, in which radiology techniques are used to do therapeutic procedures, and therapeutic radiology, with the use of x-rays in order to treat disease, mainly cancer, specifically.

The focus of chapter one in the course is diagnostic plain film radiology. This is the original radiological technique used in medicine. The history and practice of plain film radiology is discussed as well as the techniques used when x-rays are obtained of the head and neck area, chest, abdomen, and extremities. In addition, the expected results of normal and abnormal plain film x-rays are covered in this chapter. You will come to see the limitations of these types of films in the field of radiology.

The major topics of chapter two are the principles and practice of fluoroscopy, which is real-time imaging using x-ray technology rather than still pictures, and radiocontrast materials. There are many procedures that involve fluoroscopic techniques. The chapter also covers the different substances used in radiology—including those for plain film xrays, fluoroscopy, CT scanning, and MRI scanning. The different risks of giving and receiving radiocontrast material is also discussed in this chapter.

Chapter three in the course talks about ultrasound technology and how it is used in a medical setting. Ultrasonography is one method in the field of radiology that does not make use of any sort of ionizing radiation but uses high-frequency sound waves to create images from within the human body. In the chapter, we talk about how ultrasound machines work and about the different kinds of ultrasounds used in medicine. In addition, we discuss the different medical specialties and how they make use of different

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kinds of ultrasound techniques in order to do various diagnostic tests and procedures within the field of medicine.

The major discussion in chapter four is computed tomography or CT scanning, formally called a computerized axial tomography or CAT scan. The basics of how CT scanning is performed will be covered as well as the different ways CT scanning is used in various medical applications. There are related studies in radiology called the PET scan and the SPECT scan, which involve radionuclides introduced into the body that are picked up by alternate cameras and combined with CT scanning.

The topic of chapter five in the course is magnetic resonance imaging or MRI scanning. This is one of the newest methods of detection in radiology and can look mainly at the soft tissues of the body. It does not rely on the use of ionizing radiation as in many other radiological techniques but is more costly and sometimes more difficult to do than CT scanning or ultrasonography. The uses of MRI in medicine are covered in this chapter as well as the study of the brain called functional MRI, which is not yet in common usage.

There are several gastrointestinal x-ray studies looked at in chapter six. Evaluation of the upper GI tract can be done with a barium swallow, which may involve a small bowel follow-through to evaluate GI motility. There are also specialized motility tests that make use of markers that help determine gastrointestinal motility overall. The barium enema is a colonic study using contrast dye. There are specialized radiological studies that evaluate the hepatobiliary system, which are also covered in this chapter.

The focus of chapter seven in the course is breast imaging, which generally means imaging the breasts for breast cancer. The standard of breast imaging in radiology is the mammogram, which uses x-ray technology in order to visualize the breasts in a special mammography device. More recently, magnetic resonance imaging has been done in order to see breast tissue without using ionizing radiation. In lieu of an open breast biopsy, imaging techniques are being employed in order to obtain a minimally-invasive breast biopsy.

Chapter eight involves the techniques required to adequately image the heart. The standard test used for coronary arterial imaging is coronary angiography. This is usually

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done using conventional x-ray imaging and contrast dye that outlines the various coronary arteries. In addition to conventional x-rays, CT scanning can be combined with contrast techniques in order to evaluate the coronary arteries. Ultrasound is the basic technology used for echocardiography of the heart, which evaluates the blood flow and internal structures of the heart. This can be done through transesophageal or transthoracic means.

The purpose of chapter nine in the course is to cover the basics of cardiovascular imaging or the tests involved in looking at the blood vessels of the body. There are many different modalities for evaluating peripheral vascular disease, which primarily involves the lower extremities. There are similar studies that can be used to look at the veins in the lower extremities, such as in cases of deep vein thromboses of the legs. The techniques involved in carotid artery evaluation are also discussed as well as the imaging necessary to look for abdominal aortic aneurysms.

Chapter ten covers imaging in the field of obstetrics. The standard test for the evaluation of the gravid uterus is the basic obstetric ultrasound, which can evaluate many aspects of fetal anatomy, structure of the placenta, and dating of the pregnancy.

Ultrasound can also be used in certain situations in order to evaluate the blood flow through the umbilical vessels. A more targeted approach to obstetric imaging is the biophysical profile, which evaluates the viability and characteristics of the fetus near term. Ultrasound is also used to guide the needle in an amniocentesis and chorionic villus sampling.

The topic of chapter eleven in the course is gynecological imaging. The most common gynecological imaging test is the pelvic ultrasound, which is noninvasive and can evaluate all of the pelvic structures in the evaluation of pelvic pain, abnormal bleeding, and pelvic trauma. Another valuable imaging study is the hysterosalpingogram. This is a contrast dye study that is primarily used in the evaluation of infertility but has other valuable applications in the study of the uterus and fallopian tubes.

Chapter twelve looks into the various techniques used in central nervous system imaging. Plain film technology, CT scanning, MRI scanning, and ultrasound can be used to image the nervous system. Brain imaging usually involves magnetic resonance

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imaging, with special techniques used to evaluate patients with multiple sclerosis and intracranial aneurysms. Imaging of the spinal cord is also covered, including the techniques used in myelography and in identifying spinal stenosis. Intracranial ultrasound has specific indications, which is discussed in this chapter.

The focus of chapter thirteen in the course is the imaging of the urinary tract. There are special techniques involved in imaging the kidneys, ureters, and bladder, with separate techniques employed to evaluate the patient with possible renal artery stenosis.

The prostate gland in men is evaluated with a transrectal ultrasound. There are a variety of techniques used to look for adrenal adenomas and adenocarcinoma. Imaging techniques also described in this chapter include those used to identify and describe nephrocalcinosis and kidney stones.

Chapter fourteen covers the different types of radiological imaging studies used for looking at the musculoskeletal system. The study of the joints can be done with arthrography or magnetic resonance imaging of the joints. The MRI scan is especially good for identifying soft tissue anomalies so this type of scanning becomes particularly important to studying these areas. The DXA scan is used to look at bone density in the evaluation of osteoporosis. There are various techniques that can be used to look for bony metastases, which is discussed as part of this chapter.

Chapter fifteen in the course looks at the different techniques used in nuclear medicine studies. The thyroid scan involves radioactive iodine uptake that is specific to the thyroid gland. In gastrointestinal medicine, the gastric emptying study involves eating a radioactive meal with the amount of radioactivity measured in the stomach over time. The bone scan uses technetium-99 to look for bone metastases and other bony abnormalities. Finally, the ventilation-perfusion scan looks at the lungs and their ability to combine ventilation and perfusion in the act of breathing.

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CHAPTER ONE: PLAIN FILM X-RAYS The focus of this chapter is diagnostic plain film radiology. This is the original radiological technique used in medicine. The history and practice of plain film radiology is discussed as well as the techniques used when x-rays are obtained of the head and neck area, chest, abdomen, and extremities. In addition, the expected results of normal and abnormal plain film x-rays are covered in this chapter. You will come to see the limitations of these types of films in the field of radiology.

BASICS OF PLAIN FILMS Radiology as a science in medicine was not developed until 1895, when Wilhelm Roentgen took the first plain film x-ray, for which he won the Nobel Prize. This invention advanced medicine to a great degree as it allowed for a more accurate way to diagnose many different diseases, including bone fractures. Initially, x-rays were exposed onto glass plates and then plastic plates. They are currently recorded digitally in most meIdical centers.

X-ray pictures were actually discovered before radioactivity itself, which was discovered

by Antoine Henri Becquerel. Shortly thereafter, the first fluoroscope was invented by Thomas Edison. In 1913, Albert Salomon performed research that led to the first mammograms, while 14 years later, cerebral angiography was developed.

There were many advancements in radiology techniques in the twentieth century. PET scanning or positron emission tomography was developed in the 1950s as was ultrasound technology. In the 1960s, image-guided intervention was introduced and in the 1970s, both real-time ultrasonography and CT scanning were invented. Magnetic resonance imaging or MRI scanning was invented in 1977.

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WHAT ARE X-RAYS? X-rays fall on the spectrum of electromagnetic radiation, having a shorter wavelength than radio waves, microwaves, and visible light waves. X-rays have a short enough wavelength to pass through many objects, including the tissues of the human body. In plain film radiography, x-rays are passed through a body area and an x-ray detector on the opposite side of the body area collects those rays to varying degrees. Because of the different degrees of penetration, shadows are created on the image that is created. This image is referred to as a radiograph.

In order to do a plain film x-ray, the patient’s body part is positioned between the source of an x-ray and an x-ray detector. X-rays will then travel through the body, able to be absorbed to differing degrees by the tissues.

The radiological density of a tissue depends on the density of the tissue and the atomic number of the atoms the x-ray travels through. The atomic number of the calcium in bone accounts for its ability to absorb x-rays. This results in a whitish appearance. The lungs, fat, and muscle are less dense and do not absorb as many x-rays, resulting in a darker appearance.

Plain film x-rays have many different uses. The major purposes of a plain film x-ray are to detect tumors or masses, find bone fractures, see calcifications, and detect dental problems or foreign objects. Variations on plain film radiography include things like mammography or breast radiography and computed tomography or CT scanning.

Fluoroscopy uses this kind of x-ray technology in order to get real-time images of a body part.

RISKS OF X-RAY EXPOSURE In the vast majority of cases, the benefits of having an x-ray taken significantly outweigh the possible risks. Even so, x-rays expose the patient to ionizing radiation, which has the potential to harm human tissues. The risk increases with an increased number of exposures over a person’s lifetime but the chances of getting cancer from diagnostic

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radiation exposure is extremely small. Children have an increased sensitivity to ionizing radiation because of their longer life expectancy.

It is the radiation that does not get absorbed that goes through the body to be picked up by the x-ray detector. The measurement of the effective dose of radiation or the total body radiation dose is measured in millisieverts. There are other terms used less often, including gray, sievert, roentgen, rem, and rad. Tissues that absorb more radiation have a greater effective dose and are at a higher risk of complications from x-rays.

X-ray exposure happens in everyday life. Natural radiation called “background radiation” comes from outer space and from radioactive substances in the environment.

About 3 millisieverts are absorbed by the average person per year from this type of radiation. Higher altitudes mean more radiation exposure and this includes airline travel, which exposes a person to 0.03 millisieverts if traveling from coast to coast in the United States. A chest x-ray will give a person a 0.1 millisievert exposure.

Other x-ray exposures include the following: •

CT of the abdomen yields about 10 millisieverts with double that when contrast is used.

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Intravenous pyelogram yields about 3 millisieverts

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Barium enema yields about 8 millisieverts

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Upper GI exam with contrast yields about 6 millisieverts

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CT of the head yields about 2 millisieverts and double that if contrast is used.

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CT of the spine yields about 6 millisieverts

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CT of the chest yields about 7 millisieverts

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PET scan yields about 25 millisieverts

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Mammography yields about 0.4 millisieverts

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SKULL SERIES FILMS Plain film x-rays can be taken of the skull for various purposes. These types of x-rays don’t normally get used for evaluation of the brain but of the bony skull itself. There are 8 cranial bones in the skull and 14 facial bones. The base of the skull is complicated and is made of the ethmoid and sphenoid bones as well as the paired temporal bones. There are many overlapping shadows that make up the skull film. The positioning of the patient depends greatly on the bones that one is specifically looking at.

The patient can have skull imaging while recumbent or erect. The erect film is most useful for detecting air fluid levels in the sinuses or cranium. Respiration is held back during the taking of the x-ray in order to avoid breathing artifact.

There are several planes that are used for imaging the skull. There is the median sagittal plane, which is perpendicular to the ground and separates the skull into its left half and right half equally. The coronal or auricular plane is also vertical and divides the skull into its anterior and posterior portions. The transverse or anthropological plane is horizontal and divides the skull into upper and lower halves.

The PA occipital-frontal skull film is done to assess the patient for skull fractures. The patient lies prone with a vertical beam set at 20 degrees from upright. It cannot be used in patients with facial bone fractures or in the unconscious patient because of the prone position used. The patient’s nose and forehead rest against the table. Figure 1 depicts this type of x-ray:

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Figure 1.

A PA axial Caldwell film is angled caudally so that the frontal sinuses and other paranasal sinuses are best evaluated. It can also detect certain skull fractures. The patient is placed erect with the tube set to angle at 15 degrees caudally. It is centered at the nose with the midsagittal plane perpendicular to the tube.

The PA axial Haas skull film is done in order to see the sella where the pituitary gland rests. It will show clearly the foramen magnum, occipital bone, and petrous pyramids.

The patient lies prone with the x-rays directed at a 25-degree angle.

An AP fronto-occipital skull film is used to get an antero-posterior image of the skull.

The patient lies supine. This view is particularly used for patients who are unable to lie prone for a PA view.

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The AP axial Towne method is used specifically to look for fractures of the occipital bone. The patient lies supine and the beam is angled at 30 degrees from the vertical. The sella turcica will be projected through the patient’s foramen magnum. Figure 2 depicts this special view of the occipital bone:

Figure 2.

A lateral skull film can be done on a supine patient. It can be done from the left or right side and will reveal mainly skull fractures. Often, both the left and right side can be done, one after the other. The details closest to the x-ray beam are visualized the best.

The sella turcica can also be seen. A lateral skull film can be done on the erect patient as well. Figure 3 shows a lateral skull film:

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Figure 3.

The Waters view is an angled PA view of the skull that looks specifically for sinusitis or for facial fractures. The frontal and maxillary sinuses are what can most easily be seen with fractures visible on the inferior orbital rim, maxillae, zygoma, and zygomatic arch.

The patient stands upright and faces the x-ray source.

A skull film using the Schuller method will detect problems with the base of the cranium. It cannot be used in suspected cervical spine fractures or when subluxation of the cervical spine is suspected. It can be used to detect multiple areas of the face, such as the hard palate, mandible, and both the sphenoid and ethmoid sinuses. The occipital bone can also be visualized. The patient is upright or supine for this x-ray. The neck must be hyperextended in order to see the structures of the base of the skull.

CERVICAL SPINE FILMS Spine films can be done on the cervical, thoracic, or lumbar spine. In a good cervical spine film, the x-ray must visualize all seven vertebrae plus the C7 to T1 junction. The cervical spine film can be done on the erect patient in either the AP or PA view. Figure 4 shows a cervical spine film (both AP and lateral):

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Figure 4.

The lateral film is also done on the erect patient, but the side view of the patient is taken.

The arms are held to the sides and the shoulders should be kept as low as possible in order to have an unobstructed view of all seven vertebrae and the first thoracic vertebra.

An oblique view can also be done to see subtle fractures as well as the lateral foraminae.

Patients with injuries may need to have this x-ray done while supine.

The cervical AP spine can be done using what’s called the “Fuchs Method”. This is an additional view that can detect the dens located in the foramen magnum. It cannot be used on the patient with degenerative diseases of the upper cervical spine or fractures in this area. The dens or odontoid process is a process or projection of the second cervical vertebra that sticks up through the first cervical vertebra.

The Judd method of obtaining the cervical spine film looks at the dens and the atlas as they can be visualized through the foramen magnum. As in the previous technique, it cannot be used for degenerative diseases or fractures of the upper cervical spine. The patient lies prone for this view with the neck extended and the tip of the chin located on the x-ray table.

The AP odontoid process view will specifically view the odontoid process or dens through the open mouth in order to see the first and second cervical vertebrae. The patient is supine during the film with a vertical beam that is slightly angled at 10 degrees.

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The lateral Twinning method looks at the cervical thoracic region from a lateral perspective. This is also referred to as the swimmer’s lateral projection. The patient is sitting erect or can lie on one side. The arm rests on the head with the elbow flexed.

LUMBAR SPINE FILMS The good lumbar spine film will show the lower ribs, the vertebral bodies of the lumbar spine, the transverse processes, pedicles, and spinous processes of the lumbar spine, the sacrum, and the sacroiliac joints. The intervertebral disc spaces are particularly seen on the lateral film as well as the intervertebral foraminae.

The AP or PA view of the lumbar spine can be done on the supine or prone patient. It can be done on the patient who is injured with minimal movement of the patient. The patient’s knees should be flexed to keep the spine flat against the film. The lateral film can be done on the left or right side of the patient. The arms are held at a right angle to the body with the elbows flexed. Figure 5 shows an AP and lateral film of the lumbar spine:

Figure 5.

The lateral film is done to detect injuries that cannot be seen on the AP view. The patient is supine with the beam horizontal to the patient’s spine. The hands are held on the upper chest to keep them away from the view. The knees may need to be flexed in order

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to decrease lumbar lordosis. An oblique view can be obtained in order to better see the articular processes or lumbosacral processes. The patient is turned to 45 degrees to get this oblique view.

The sacrum is best evaluated through an AP view. The x-ray evaluates the sacroiliac joints and the lumbosacral junction. The patient is supine with a vertical beam that is angled at 15 degrees. It cannot be used in children. The bladder needs to be emptied if possible. A lateral view can also be taken of the lumbosacral junction. The patient lies on their side in order to get this view.

CHEST X-RAY The patient can have plain x-rays of the chest, which is particularly helpful in detecting heart, lung, chest wall, and diaphragmatic injuries. This is the initial film used to detect lung abnormalities. Unlike many films, this is a PA film and not an AP film, because the goal is to minimize x-ray scatter. Oblique or lordotic views can be taken of the chest in order to evaluate the patient for nodules or to see things that are overlapping. A lateral decubitus film can look at pleural effusions to see if there are loculations or free-flowing liquid in the pleural space. An end-expiratory view can detect small pneumothoraxes in the patient. Portable views are not very helpful unless the patient is too sick for a regular chest x-ray.

The plain film can detect problems in the chest in the patient who has persistent cough, shortness of breath, fever, chest injury or chest pain. It does not show as much as a CT scan of the chest but is rapid and easy to do for situations of pneumonia, COPD, and certain lung cancers. It is the most commonly done x-ray test in radiology. Usually, both the lateral and PA views are taken of the chest. The patient is usually standing upright for this film.

The radiologist looking at a chest x-ray should remember the mnemonic ABCDEF when looking at a standard chest film. This stands for airways, bones, cardiac outline, diaphragm, expansion of the lungs, and foreign bodies.

In taking this film, the patient should stand with the shoulders pressed forward to get the PA view. The top of the lungs and the diaphragm should be completely visible. The 14

patient should take a deep breath and hold it for the taking of the x-ray. Figure 6 shows a good chest x-ray film:

Figure 6.

On the lateral film, the patient is also erect and usually the left lateral is taken. The patient should lean slightly forward during the taking of the film. The arms are above the head or locked behind the back in order to rotate the shoulders in the posterior direction. Again, the patient should have expanded lungs and should hold their breath.

The top and bottom of the lungs should be visualized.

A PA and lateral of the chest can be done on the patient while sitting erect if they are unable to stand. The tests are otherwise identical to the standing image. The entire lungs should be visualized, including the top of the lungs, the lower parts of the diaphragm, and the costophrenic angles on both sides.

The AP chest is only done on the patient who is unable to sit or stand. It is done on the supine patient. The apical or lordotic AP film is done to get an added view of the upper

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lungs and chest cavity. The patient lies down and reclines backward. Just the upper part of the chest needs to be visible.

The chest PA oblique film or the Moore method is used primarily to get a view of the sternum. It is a modified prone film in which the patient stands and bends at the waist.

The arms are placed above the head. The entire sternum should be visible on the chest x-ray. The Kurzbauer method is related to this but images the sternoclavicular articulation.

The ribs are detected with oblique views. The patient can stand or sit erect for this evaluation. A left or right oblique film can be obtained. If the patient cannot stand or sit, they can lie supine and can be supported with pillows. The arms are raised as high as possible so the ribs can be visualized.

In infants up to fifteen kilograms, the child can be held erect and will hang by the upper arms with the feet supported. Ideally, the film should be taken when the infant is inspiring and when not moving. Infants up to ten kilograms can be assessed with an AP supine film. The beam is directed between the nipples.

ABDOMINAL FILMS Abdominal films can assess the stomach, intestines, liver, and spleen in evaluating abdominal pain or other GI symptoms, although a CT scan or contrast study would be better. A related evaluation of the kidneys, ureters, and bladder is called a KUB film. The plain film is best used for gallstones, genitourinary stones, intestinal or stomach perforation, gastrointestinal obstruction, or for foreign body evaluation. Catheter placement is done using a plain film x-ray.

A good quality film will show the entire abdomen, from the diaphragm to the pelvis. The radiologist should use the mnemonic BBC in evaluating this type of film. The BBC stands for bowel and other organs, bones, and calcifications. Usually, an AP film is gotten in the supine patient with the patient breathing out completely.

Other abdominal films that can be gotten include the AP erect film to demonstrate intestinal obstruction or perforation. The diaphragm should be seen to evaluate the

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patient for free air. A lateral decubitus film will detect these things as well in the patient who is not able to ambulate. In the lateral decubitus, the upper side of the abdomen should be seen in order to evaluate the patient for free air in the abdominal cavity. The AP erect is done on infants weighing up to fifteen pounds.

The urinary tract can be evaluated with a plain film that includes images of the kidneys, ureters, and bladder. IV contrast is used to outline these structures in the supine patient. Images are obtained immediately after the injection and again after ten minutes. A final film is taken after the bladder is filled with contrast or about 25 minutes after the injection of contrast material.

A lateral film is taken in late pregnancy in order to look for cephalopelvic disproportion in the patient with an arrest or possible obstruction of labor. It is used when an ultrasound cannot be performed. An AP or PA of the pelvis can also be obtained for this purpose.

SHOULDER FILMS A shoulder film is done to evaluate a person for fractures of the affected area, for shoulder dislocation, or for other bony abnormalities of the shoulder. Soft tissue problems, like calcifications of the rotator cuff muscles can be seen on a plain film of the shoulder. The standard image is of the AP shoulder that can be internally or externally rotated. Figure 7 shows a typical shoulder x-ray:

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Figure 7.

You can also get a Y image, which is a lateral image of the scapula, an axial image, or an apical oblique image. The difference is the angle at which the beam is aimed toward the shoulder. These images can help detect subluxations or dislocations of the shoulder.

There is a special acromioclavicular or AC image taken at a ten-degree angle from the horizontal, directed upward to view the AC joint. The Y image is called this because the scapula, the scapular spine, and the coracoid process together form a Y shape. In the AC joint view, the bottom of the acromion needs to be aligned with the bottom of the clavicle. If this does not happen, think of an AC subluxation or dislocation. Figure 8 shows this alignment:

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Figure 8.

For evaluation of fractures of the proximal humerus, the Neer classification is used. This divides the humeral head into four segments. Segment I is the humeral shaft; segment II is the humeral head; segment III is the greater tubercle where most of the rotator cuff muscles insert; segment IV is the lesser tubercle, where the subscapularis muscle inserts. Figure 9 shows these segments:

Figure 9.

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As you can see by the figure, the anatomical neck is located between the two tubercles and the head of the humerus. The surgical neck is below that and is a site for many fractures. Dislocation is noted when any segment moves more than one centimeter or when there is curvature or angulation of a segment more than forty-five degrees.

The Neer classification is determined by the parts that are left after the fracture. In a one-part fracture, there is a simple non-dislocated fracture, while in a four-part fracture, there is dislocation through all four parts of the proximal humerus with four separate fracture segments. More than ninety percent of these are one-part fractures. CT scanning is done in a three or four-part fracture.

Luxation or dislocation involves a disruption in the relationship between two components of the joint. More than 95 percent of shoulder subluxations are anterior.

This can be seen in several images of the shoulder joint. Figure 10 shows a dislocated shoulder:

Figure 10.

Traumatic dislocation of the shoulder will often cause an impaction fracture of the humeral head, known as a Hill-Sachs lesion. The lesion will be seen on the posterolateral side of the humerus so it requires internal rotation of the shoulder in order to see it. There is a Bankart lesion, located on the opposite side of a Hill-Sachs

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lesion. This is seen with posterior dislocations of the shoulder. They often need CT scan or MRI scanning in order to detect these.

The AC joint dislocation is seen on the AC image of the shoulder joint. If there is a dislocation of more than eight millimeters, this is representative of a significant subluxation. You may need to get an image of the opposite side in order to have a representation of what the normal AC joint looks like.

Osteoarthritis of the shoulder can be detected on x-ray. It can be a primary problem or secondary to a fracture or rotator cuff injury. There will be narrowing of the joint space from loss of cartilage, subchondral sclerosis with increased bone production, osteophyte formation, synovitis, and subchondral cysts.

Rotator cuff impingement is seen when the rotator cuff tendons have been pinched between areas of bone. The pain is anterior and lateral with abduction or lifting of the arm being the most painful. The impingement usually occurs between the top of the acromion and the humeral head. This can lead to weakness and degeneration of the tendons. The supraspinatus tendon is the most susceptible to this type of impingement.

The plain film can be helpful because it can show calcifications of the tendon.

ELBOW PLAIN FILMS This generally results in obtaining a standard AP and lateral image of the elbow, although a capitellum image can be done, which views the radial head. The AP image is done with the palm facing up, which is external rotation of the elbow. A good film takes one of the joint and a third each of the distal humerus and the proximal radius and ulna.

The lateral involves the shoulder at the same level as the elbow with the medial side of the patient’s arm in contact with the x-ray table. The palm faces the patient. The elbow is flexed to ninety degrees. The capitellum image is of the radial head for subtle fractures of this structure. The patient is positioned the same way as the lateral image with the image taken at a 45-degree angle to the x-ray table.

There are actually three separate joints in the elbow. The humeroulnar joint involves the olecranon of the ulna articulating with the humerus through its trochlea. The

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radiohumeral joint is between the radial head and the humerus. It is involved with pronation and supination of the forearm. The proximal radioulnar joint is between the proximal radius and proximal ulna. It rotates the radial head.

On the lateral image, there are fat pads located posteriorly and anteriorly. These are located within the articular capsule and can be seen in cases of elbow fracture. Figure 11 shows a normal elbow x-ray. https://www.shutterstock.com/image-photo/xray-view-elbow218095324?src=bgoiuSHHVIbjgZ9h1OxCNQ-1-2

Figure 11.

The elbow will not be developed in the child. There are six different ossification centers in the elbow that take up to 11 years to fully develop. The lateral epicondyle develops last of these major centers of ossification. These different areas of ossification make it difficult to assess the patient for fractures prior to the age of eleven years.

A radial head fracture can happen with a fall on the outstretched arm or a valgus stress on an abducted arm. These can be subtle fractures. There will be fat pad displacement in

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