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eFigure 9–17. A: Pulmonary embolism (CXR). The heart is significantly enlarged, with prominence of main pulmonary arterial outflow as indicated by fullness in the region of the pulmonary hila. However, there are no other changes in the peripheral lung suggestive of a pulmonary embolus. B: PE (pulmonary angiogram). A large embolus is present in the right main pulmonary artery at its point of bifurcation between the upper and middle and the lower lobe vessels, resulting in a paucity of perfusion of vessels distal to the embolus. A chest radiograph shows that the heart located between the lungs is enlarged. A pulmonary angiogram shows a large mass present in the right main pulmonary artery, at the point of its branching.

Current Medical Diagnosis & Treatment 2024 > Pulmonary Venous Thromboembolism

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eFigure 9–17. A: Pulmonary embolism (CXR). The heart is significantly enlarged, with prominence of main pulmonary arterial outflow as indicated by fullness in the region of the pulmonary hila. However, there are no other changes in the peripheral lung suggestive of a pulmonary embolus. B: PE (pulmonary angiogram). A large embolus is present in the right main pulmonary artery at its point of bifurcation between the upper and middle and the lower lobe vessels, resulting in a paucity of perfusion of vessels distal to the embolus. A chest radiograph shows that the heart located between the lungs is enlarged. A pulmonary angiogram shows a large mass present in the right main pulmonary artery, at the point of its branching.

Current Medical Diagnosis & Treatment 2024 > Pulmonary Venous Thromboembolism

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eFigure 9–19. Normal lung perfusion. A routine examination may include as many as eight views– anterior, posterior, right and left anterior and posterior obliques, and both right and left laterals (A to H). Some physicians prefer to omit the anterior obliques; others do not include the laterals. There is general agreement that the posterior obliques are the most valuable views. When the patient is injected in the supine position, the radioactive particles are evenly distributed throughout the lungs, with a gently increasing gradient of activity from the upper anterior to the lower posterior lung fields. The cardiac and mediastinal spaces between the lungs have a configuration in the combined anterior and posterior views similar to that of the respective area in the posteroanterior CXR. Cardiomegaly and mediastinal masses will cause distortions that are common to both examinations. An enlarged cardiac space may be caused by cardiomegaly and by effusions or other conditions of the pericardial sac and adjacent pleural cavity. If the patient is rotated, the lung images may override and cause a false defect, which will disappear when the patient is repositioned accurately. However, a true lesion is unlikely if seen in only one view of a complete study. (Reproduced, with permission, from Baum S et al. Atlas of Nuclear Medicine Imaging, 2nd ed. Originally published by Appleton & Lange. Copyright © 1992 by The McGraw-Hill Companies, Inc.) A normal lung perfusion scan shows normal perfusion in six different views of the lungs.

Current Medical Diagnosis & Treatment 2024 > Pulmonary Venous Thromboembolism

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eFigure 9–20. Normal lung ventilation with xenon-133. With the patient’s single full breath, inhaled radioxenon is evenly distributed to all lung areas, reaching the terminal airways and alveoli in the normal patient (A, posterior view). There is a less noticeable gradient of activity from the upper to the lower lung fields than is seen in perfusion lung images. Fifteen-second images obtained during closed-system rebreathing of a xenon–oxygen mixture show uniform distribution at 120 seconds (B). Serial 15-second frames after switching the patient to room air breathing (C to G) show a homogeneous pattern of washout from all lung areas. This sequence mainly evaluates the posterior lung regions. To better localize gas trapping in specific lung segments or more anterior regions, the acquisition may be modified after the rebreathing phase by rotating the patient into posterior oblique positions. Selected images from a complete study include single breath (H, posterior view), the late phase of rebreathing (I, posterior view), posterior washout (J), left posterior oblique washout (K), and right posterior oblique washout (L). No gas is retained in this patient, which is normal, but in obstructive airway disease gas retention persists and is better localized in the oblique views than in a posterior view alone. A small amount of alveolar xenon normally crosses the alveolar membrane to reach the blood and be distributed throughout the body. Because it is highly soluble in lipids, xenon accumulates in adipose tissue, including the liver, which is faintly seen with prolonged rebreathing. Liver activity should not be mistaken for delayed washout of xenon from the base of the lung. Occasionally, splenic blood pool radioactivity or swallowed xenon in the stomach may also be seen. (SIN BRE = single breath, L REB = late rebreathe, WO = washout.) (Reproduced with permission from Grippi MA, Elias JA, Fishman JA, Kotloff RM, Pack AI, Senior RM, Siegel MD. Fishman’s Pulmonary Diseases and Disorders, 5e. 2015.) Four examples of normal ventilation scans compared with eight examples of abnormal scans.

Current Medical Diagnosis & Treatment 2024 > Pulmonary Venous Thromboembolism

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Figure 7–2. Acute central retinal artery occlusion with cherry-red spot (arrow) seen at the fovea centered in macular loss of retinal transparency, and preserved retinal perfusion (arrowheads) adjacent to the optic disk due to macular cilioretinal artery supply. (Reproduced, with permission, from Riordan-Eva P, Augsburger JJ. Vaughan & Asbury’s General Ophthalmology, 19th ed. McGraw Hill, 2018.) An image shows a dark spot in the retina, adjacent to the optic disk.

Current Medical Diagnosis & Treatment 2024 > Central & Branch Retinal Artery Occlusions

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eFigure 10–32. Rest and 24-hour redistribution thallium-201 (201Tl) single-photon emission CT (SPECT) myocardial perfusion imaging (MPI) of a 75-year-old man with atypical angina showing a large amount of resting ischemia in the left anterior descending coronary artery (LAD). Coronary angiography subsequently revealed a 95% proximal LAD stenosis. Of note, the LV was larger at rest than at the time of redistribution imaging. The stress SPECT-MPI study was canceled in this patient because of the unexpected perfusion defect. (Reproduced, with permission, from Fuster V, Harrington RA, Narula J et al. Hurst's The Heart, 14th ed. McGraw-Hill, 2017.) A set of diagnostic images compares test results from SPECT M P I in a case of atypical angina.

Current Medical Diagnosis & Treatment 2024 > Chronic Stable Angina Pectoris (Chronic Coronary Syndromes)

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eFigure 10–31. A 38-year-old man with chest pain at physical exercise. At rest, a mildly decreased perfusion is seen in the anterior wall and apex. At stress, severely decreased perfusion in the same region is seen. At gated single-photon emission CT (SPECT), larger volumes and lower EF are seen after stress compared with rest, indicating postischemic stunning. Because of severe ischemia, the patient was referred for prompt angiography showing a proximal significant stenosis in the left anterior descending artery, which was treated with percutaneous coronary intervention. The reduced perfusion at rest is most likely caused by resting ischemia because the patient had no history of MI. EDV, end-diastolic volume; ESV, end-systolic volume. (Reproduced, with permission, from Pahlm O, Wagner G. Multimodal Cardiovascular Imaging: Principles and Clinical Applications. McGraw-Hill, 2011.) A diagnostic image shows test results from radionuclide imaging for reversible ischemia.

Current Medical Diagnosis & Treatment 2024 > Chronic Stable Angina Pectoris (Chronic Coronary Syndromes)

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