Radiology Fundamentals

Voorwerk

1. Patient Radiation Safety and Risk

Abstract

Everyone is concerned about patient radiation dose. From 1993 through 2008, ­radiation dose attributed to medical radiation rose 82% from 0.54 to 3 mSv per capita. The largest component of the medical patient radiation dose was CT scanning (49%). This is despite the fact that CT scanning makes up only 17% of the total medical procedures that contributes to a patient radiation dose (NCRP Report 160).

Harjit Singh, Janet A Neutze

2. Introduction to Radiology Concepts

Abstract

Let us disregard the anatomy seen on the radiograph for now and concentrate on basic radiographic principles. In Fig. 2.1, you can see examples of the four basic densities, bone, soft tissue, fat, and air, which are visible on a conventional radiograph.

Harjit Singh, Janet A Neutze

3. Conventional Radiology

Abstract

The main purpose of this chapter is to demonstrate the effect of various technical ­factors on the appearance of conventional radiographs.

Harjit Singh, Janet A Neutze

4. Ultrasound

Abstract

Ultrasound uses no ionizing radiation and it can image directly in any body plane. In practice, an ultrasonographer (either a technologist or a radiologist) places gel on the patient’s skin and moves a transducer across the surface of the patient’s body. The gel forms an acoustic seal between the transducer and the skin for better transmission of sound, which results in better images.

Harjit Singh, Janet A Neutze

5. Computed Tomography

Abstract

Computed tomography (CT) uses ionizing radiation to create a cross-sectional image. This allows visualization of a greater variety of tissue structures beyond the four basic densities (air, bone, soft tissue, and fat) that are seen on a conventional radiograph. Unlike conventional X-rays, which utilize one projection to form an image, CT uses ­multiple small projections across the body and combines the information to form the image. It is this combining of the images that allows greater soft tissue detail to be displayed.

Harjit Singh, Janet A Neutze

6. MRI

Abstract

Magnetic resonance imaging (MRI) has its greatest application in the fields of ­neuroradiology and musculoskeletal radiology.

Harjit Singh, Janet A Neutze

7. Nuclear Medicine

Abstract

The first step in any nuclear medicine diagnostic imaging study involves the administration of a radiopharmaceutical to a patient. A radiopharmaceutical is a chemical combination of a radionuclide and a pharmaceutical (Fig. 7.1). A radionuclide is an unstable isotope of an element which emits radiation to achieve stability. When this radiation is in the form of gamma rays, it can be detected by a nuclear medicine gamma camera (Fig. 7.2). A pharmaceutical is a compound which localizes in normal or diseased tissue. A nuclear medicine image depends on the physiologic distribution of the pharmaceutical which is administered.

Harjit Singh, Janet A Neutze

8. Cardiovascular and Interventional Radiology

Abstract

In cardiovascular and interventional radiology (CVIR), a combination of needles, wires, catheters, balloons, and stents are used to accomplish many things through small access points in the skin.

Harjit Singh, Janet A Neutze

9. Heart and Mediastinum

Abstract

When evaluating the cardiac/pericardial outline and mediastinal contours, it is easiest to follow the right and left borders that these structures make with the aerated lung. Although the mediastinum is optimally visualized by various cross-sectional imaging techniques, the initial stage of evaluation is often through plain radiographs.

Harjit Singh, Janet A Neutze

10. Lateral Chest

Abstract

Begin by reviewing the systematic approach to the left lateral chest radiograph in Fig. 10.1

Harjit Singh, Janet A Neutze

11. Pulmonary Mass Lesions

Abstract

Masses within the lung are commonly suspected and/or appreciated on the ­conventional chest radiograph. There are many criteria which you should evaluate on arriving at a list of potential differential diagnoses for a mass lesion.

Harjit Singh, Janet A Neutze

12. Air Space Disease

Abstract

The purpose of this unit is to demonstrate the appearance of air space disease in the lungs.The pulmonary acinus is the basic structural unit of the lung involved in gas exchange. It consists of a terminal bronchiole and the alveolar ducts, sacs, and alveoli distal to it.

Harjit Singh, Janet A Neutze

13. Interstitial Disease

Abstract

The alveoli, conductive airways, and blood vessels of the lung are surrounded by the pulmonary interstitium. The interstitial space can be subdivided into three components as noted in the accompanying drawings.

Harjit Singh, Janet A Neutze

14. Atelectasis

Abstract

You will find few chest radiographic reports that do not include the term atelectasis. Atelectasis means incomplete lung expansion. This term is frequently tossed about and little thought is given to its significance.

Harjit Singh, Janet A Neutze

15. Pulmonary Vasculature

Abstract

We have already seen how inspiration and expiration can affect the appearance of the pulmonary vessels. Other technical factors such as under-penetration and supine positioning can also make the vessels look artifactually prominent.

Harjit Singh, Janet A Neutze

16. Pulmonary Edema

Abstract

Pulmonary edema secondary to left ventricular failure is one of the more common problems encountered in clinical medicine. The term congestive heart failure (CHF) is often applied both clinically and radiographically. Technically, CHF is a clinical diagnosis with a constellation of findings some of which are radiographic. Nevertheless, the terms cardiogenic pulmonary edema, left ventricular failure and CHF are often used synonymously in informal discussion.

Harjit Singh, Janet A Neutze

17. Pneumothorax

Abstract

A diagnosis that seems to cause much confusion in the clinical situation is that of a pneumothorax, which is the presence of air in the pleural space. Air is not normally present in this space. The visceral and parietal pleura are exclusively in contact with each other except for a very thin layer of intervening fluid which is not normally visible radiographically (Fig. 17.1). The expected appearance of a pneumothorax can be anticipated by using the basic principles which have already been introduced.

Harjit Singh, Janet A Neutze

18. Miscellaneous Chest Conditions

Abstract

The following radiographs show examples of entities with diagnostic radiographic presentations. By seeing the “classic” examples of these entities, you will hopefully gain enough familiarity to make the diagnosis should you encounter them clinically.

Harjit Singh, Janet A Neutze

19. Tubes and Lines

Abstract

The main point of the following radiographs is to show normal and abnormal ­positions of various commonly seen tubes and catheters.

Harjit Singh, Janet A Neutze

20. Breast Imaging

Abstract

Breast carcinoma is the most common neoplasm in women, with approximately 200,000 new cases each year. The early detection of breast cancer with mammography has contributed to a decrease in mortality of up to 40%. There have also been improvements in the therapy for breast cancer with agents that target cancers based on their individual biology.

Harjit Singh, Janet A Neutze

21. Women’s Ultrasound

Abstract

Women’s imaging is a subspecialty area of radiology devoted to the diagnosis and treatment of conditions and diseases which are unique to women. Women’s imaging uses all imaging modalities to evaluate gynecologic and obstetrical conditions, breast health, and contributes to urologic evaluations and overall health.

Harjit Singh, Janet A Neutze

22. Women’s Health Interventions

Abstract

“Women’s health interventions” is a newly coined term in Interventional Radiology. It describes the group of Interventional Radiology procedures that are related to female pelvic structures and includes Uterine Artery Embolization (UAE) or Uterine Fibroid Embolization (UFE), Ovarian Vein Embolization for Pelvic Congestion Syndrome (PCS), and Fallopian Tube Recanalization. Each procedure will be ­discussed separately.

Harjit Singh, Janet A Neutze

23. Abdominal Calcifications

Abstract

Calcifications are frequently seen on radiographs of the abdomen. The purpose of this section is to demonstrate the typical appearance of the more commonly occurring calcifications.

Harjit Singh, Janet A Neutze

24. Abnormal Air Collections in the Abdomen

Abstract

When a hollow viscous ruptures, air (and bowel contents) is released into the abdominal cavity. “Free air” will collect in the least-dependent (highest) portion of the peritoneum.

Harjit Singh, Janet A Neutze

25. Barium Studies of the Upper GI Tract

Abstract

Barium sulfate is commonly employed for radiographic visualization of the ­gastrointestinal (GI) tract. For the upper GI (UGI), the barium sulfate mixture is swallowed and traced radiographically as it passes through the oropharynx, hypopharynx, esophagus, and more distal GI tract. When there is a concern of perforation or obstruction, water soluble contrast should be used.

Harjit Singh, Janet A Neutze

26. Barium Enema and CT Colonography

Abstract

As with the upper GI series, the barium enema can be performed in either a single- or double-contrast fashion. In single-contrast studies the colon is filled only with barium. This demonstrates an extrinsic displacement of the colon, such as might be seen in a pelvic mass in a patient with a gynecological malignancy, to the greatest advantage.

Harjit Singh, Janet A Neutze

27. Bowel Obstruction

Abstract

Gas is normally present in the stomach and colon. Small accumulations of gas may be found in the duodenum and upper portion of the jejunum. Scattered collections of gas may be present throughout much of the small intestine in bedridden patients, patients on narcotics for pain relief, and those who swallow large amounts of air habitually. Air can be seen as individual accumulations of rounded or ovoid shaped air.

Harjit Singh, Janet A Neutze

28. Inflammatory Bowel Disease

Abstract

The two most common inflammatory bowel diseases (IBDs) are Crohn’s Disease (CD) and ulcerative colitis (UC).

Harjit Singh, Janet A Neutze

29. Defecography

Abstract

Defecography is a special radiological study performed to evaluate patients with evacuatory disorders either from structural or functional abnormalities.

Harjit Singh, Janet A Neutze

30. Intra-abdominal Lymphadenopathy

Abstract

Lymph node enlargement (lymphadenopathy) may be found in many conditions, both benign and malignant. Benign lymph node enlargement can occur in response to different infections such as tuberculosis and fungal disease. Malignant lymphadenopathy can occur in primary lymphatic diseases such as Hodgkin’s and non-Hodgkin’s lymphoma, as well as other malignancies which metastasize to regional lymph nodes, such as breast cancer.

Harjit Singh, Janet A Neutze

31. The Gallbladder

Abstract

Right upper quadrant pain is one of the most common clinical presentations and the gallbladder is one of the most frequently imaged organs in this setting. There are numerous radiographic tests for evaluation of the gallbladder.

Harjit Singh, Janet A Neutze

32. Abdominal and Pelvic Pain Evaluation

Abstract

Patients with abdominal and/or pelvic pain are commonly encountered in the emergency department and throughout all of the primary care and specialty clinics. The imaging assessment of these patients depends upon their clinical presentation (acute vs. chronic pain, point tenderness vs. generalized discomfort), laboratory data (elevation of liver function tests, serum amylase, white cell count, hematocrit), age, gender, and frequently the availability of the various diagnostic imaging tests.

Harjit Singh, Janet A Neutze

33. Imaging the Trauma Patient

Abstract

Trauma patients frequently are imaged in the emergency department, as they are at high risk for significant internal injuries that would not be evident on conventional radiographs. Many institutions use “Fast” scan ultrasound (Focused Assessment with Sonography in Trauma), a way of surveying the certain portions of the abdomen and pelvis looking for free fluid, which may indicate the presence of hemorrhage. When free fluid is found, the patient is then generally evaluated with enhanced computed tomography.

Harjit Singh, Janet A Neutze

34. Concerning Lesions

Abstract

An abscess is a collection of infected fluid and inflammatory debris that has been walled off by the body’s immune system. Any inflammatory process in the abdomen or pelvis such as appendicitis, diverticulitis, and Crohn’s disease, can lead to an abscess. Traumatic puncture wounds and foreign bodies can also result in abscess formation. Common locations for an abdominal abscess are the subphrenic and subhepatic spaces. Abscesses can also develop in organs, such as the liver (intrahepatic abscess) or kidney (renal abscess). An abscess must be promptly treated with antibiotics and either percutaneous or surgical drainage to prevent systemic infection or sepsis.

Harjit Singh, Janet A Neutze

35. Incidental Lesions

Abstract

The advent of high quality cross-sectional imaging has revolutionized medical and surgical diagnosis and treatment. However, it has also lead to the discovery of numerous incidental findings that may require evaluation to determine whether they may be safely dismissed or if further workup is required.

Harjit Singh, Janet A Neutze

36. Radionucleotide Evaluation of GI Bleeding

Abstract

The radiopharmaceutical used in nuclear medicine to detect gastrointestinal bleeding is Technetium 99m-labeled autologous red blood cells (Tc-99m RBC). Labeling of red blood cells is possible because the radionuclide technetium 99m pertechnetate (TcO ₄ ⁻ ) freely crosses the red blood cell membrane via anion exchange. However, once TcO ₄ ⁻ is reduced, it can no longer pass through the red blood cell membrane. Therefore, it follows that if TcO ₄ ⁻ is allowed to cross the RBC membrane and subsequently reduced within the cell, Tc-99m will be trapped within the RBC. This is precisely how RBCs are labeled for a nuclear medicine GI bleeding study. The agent used to reduce TcO ₄ ⁻ is tin (Sn⁺²). The protocol involves pretreating red blood cells with tin followed by exposure to TcO ₄ ⁻ . The intracellular tin reduces the TcO ₄ ⁻ trapping it within the cell. The reduced technetium 99m binds to the beta chain of hemoglobin (see Fig. 36.1

Harjit Singh, Janet A Neutze

37. Radionucleotide Bone Imaging

Abstract

When technetium 99m is bound to methylene diphosphonate, the resulting ­compound is called technetium 99m-MDP. Administered intravenously, as much as 60% of this substance will be taken up by the skeleton through a process called chemabsorption by which the tracer is actually incorporated into the calcium hydroxyapatite crystal matrix of bone or other calcium depositions. The remainder of the tracer is excreted via the urinary tract. Gallium, another radioactive material, is not used as a primary agent for bone scans now that MDP bone scanning is available (Fig. 37.1)

Harjit Singh, Janet A Neutze

38. Lung Ventilation and Perfusion Imaging

Abstract

Ventilation and perfusion scans are used for detecting pulmonary oxygenation abnormalities.

Harjit Singh, Janet A Neutze

39. Radionucleotide Cardiac Imaging

Abstract

Radionucleotide imaging is an important part of the diagnostic arsenal used in evaluation of the heart. This is because, in addition to displaying anatomic features, radionucleotide images are also a graphic representation of normal and abnormal myocardial physiology. In this unit, we will consider two important uses of radionucleotide imaging with regard to the heart.

Harjit Singh, Janet A Neutze

40. F-18 FDG Positron Emission Tomography

Abstract

The radiopharmaceutical used in positron emission tomography is Fluorine-18 fluorodeoxyglucose (F-18 FDG).

Harjit Singh, Janet A Neutze

41. Diagnostic Arteriography

Abstract

Arteriography involves the placement of a catheter into the arterial system with injection of contrast while obtaining X-ray images. Various catheters and wires are used in combination to cannulate the desired arteries (Fig. 41.1).

Harjit Singh, Janet A Neutze

42. Pulmonary Arteriography and IVC Filter Placement

Abstract

Although still considered the gold standard for the diagnosis of pulmonary embolism, pulmonary arteriography has largely been supplanted by pulmonary CT scan angiography (CTAP). Nevertheless, pulmonary arteriography may still be indicated in patients with a high clinical suspicion for pulmonary embolism and A low probability or indeterminate V/Q scan or CTAP. An indeterminate V/Q or CTAP and contraindication to anticoagulation.

Harjit Singh, Janet A Neutze

43. Percutaneous Nephrostomy Placement

Abstract

Percutaneous drainage of the kidney is performed for several reasons, the most common of which is obstruction from nephrolithiasis, kidney stone disease. Obstructive uropathy secondary to a ureteral stone can be a medical emergency, particularly if there is evidence of urosepsis from ureteral obstruction. In those cases, percutaneous drainage may be a life-saving measure.

Harjit Singh, Janet A Neutze

44. TIPS

Abstract

The Transjugular Intrahepatic Portosystemic Shunt (TIPS) is a percutaneous procedure designed to decompress the portal system in patients with portal hypertension (Table 44.1).

Harjit Singh, Janet A Neutze

45. Central Venous Access

Abstract

Maintenance of venous access is the cornerstone of many medical therapies. Durable venous access into the central venous systems is essential for most cancer regimens, extended antibiotic therapies, parenteral nutrition, and inotropic therapies. Durable central venous access for patients who require hemodialysis serves as a bridge until a dialysis fistula or graft is established or as a means of last resort when a graft or fistula is no longer possible. Increasingly, the placement of a long-term central venous access device is performed using ultrasound and fluoroscopic image guidance and is most commonly performed by Interventional Radiology.

Harjit Singh, Janet A Neutze

46. Fractures: Part I

Abstract

Fractures are ubiquitous in medical practice. Radiographs have been used to ­evaluate fractures from the earliest days of diagnostic radiology and remain a ­cornerstone of clinical care in the diagnosis and treatment of skeletal trauma.

Harjit Singh, Janet A Neutze

47. Fractures: Part 2

Abstract

Figure 47.1 shows a normal two view study of the shoulder as might be obtained in the emergency room.

Harjit Singh, Janet A Neutze

48. Arthritides

Abstract

The typical radiographic characteristics of osteoarthritis include ( Fig. 48.1 ). Asymmetric joint space narrowing - This indicates loss of articular cartilage. For example, the hip migrates superiorly because of the loss of cartilage superiorly along the weight-bearing surface. Subchondral sclerosis ( also called eburnation ) - This is caused by trabecular compression and fracture with callus formation. Osteophyte formation.

Harjit Singh, Janet A Neutze

49. Bone Tumor Characteristics

Abstract

This chapter is not an exhaustive description detailing the characteristics of various types of bone tumors. It does, however, provide a paradigm to evaluate and classify types of bone tumors which allows for the creation of a useful differential diagnosis when a new bone tumor is encountered in clinical practice.

Harjit Singh, Janet A Neutze

50. CNS Anatomy

Abstract

Figures 50.1 and 50.2 demonstrate a normal CT and MRI of the brain. Be sure to become familiar with the labeled structures.

Harjit Singh, Janet A Neutze

51. The Cervical Spine

Abstract

Plain radiographs of the cervical spine are the initial imaging modality, where the frontal, lateral, and AP views may be supplemented by additional views (like the “open-mouth” and extension/flexion views) (Fig. 51.1).

Harjit Singh, Janet A Neutze

52. Head Trauma

Abstract

With the advent of CT scans, the role of routine skull radiographs in neurologic trauma has become limited. In moderate and severe head trauma, a CT scan is the study of choice. Skull radiographs are only indicated in minor head trauma patients where a CT scan is otherwise not clinically indicated during the initial evaluation.

Harjit Singh, Janet A Neutze

53. Stroke

Abstract

Stroke is a clinical syndrome. It is used somewhat colloquially to refer to a group of clinical syndromes that involve mental status changes. Although most of us think primarily of cerebrovascular accident (CVA) when we hear “stroke,” there are other processes which could mimic CVA, such as hemorrhage, seizure, tumors, etc.

Harjit Singh, Janet A Neutze

54. Headache and Back Pain

Abstract

Many disease processes manifest as headache. While headaches are mostly benign and self-limited, imaging is often obtained to exclude acute or life-threatening processes, such as a hemorrhage or mass.

Harjit Singh, Janet A Neutze

55. Radiology Coming Soon

Abstract

Radiology, as we have alluded to many times in this text, is a fast moving field. It is likely that the three “coming soon” areas in radiology described in this chapter will be relatively common in practice by the time you read about them here. Moving at the “speed of light” is what makes this field so exciting.

Harjit Singh, Janet A Neutze

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