Karteikarten
Exam 2- CT
Karten in diesem Stapel (117)
- 1—High Cardiac Level.
At this level, you should be able to identify the left atrium (LA), right atrium (RA), aortic root (Ao), and right ventricular outflow tract (RVOT). The left atrium occupies the pos- terior and central portion of the heart. One or more pulmonary veins may be seen to enter the left atrium (white arrow). The right atrium produces the right heart border and lies anteriorly and to the right of the left atrium. DA, Descending thoracic aorta; LV, Left ventricle - 2—Low Cardiac Level.
At this level, you should be able to identify the right atrium (RA), right ventricle (RV), left ventricle (LV), and interventricular septum (IVS). The right ventricle is more heavily trabeculated (solid white arrow) and has a thinner wall (dotted white arrow) than the wall of the left ventricle (solid black arrows). DA, Descend- ing thoracic aorta.
- 3—Main Pulmonary Artery Level
(A) Mediastinal Window and (B) Lung Window. (A) At this level, you should be able to identify the main (MPA), right (RPA), and left pulmonary arteries (LPA), the right (RB) and left main bronchi (LB), and the superior vena cava (S). The left pulmonary artery passes anterior to the descending aorta (DA). The right pulmonary artery passes posterior to the ascending aorta (AA) and crosses to the right side. (B) Distal to the takeoff of the right upper lobe bronchus is the bronchus intermedius (BI). The posterior wall of the right upper lobe bronchus is 2 to 3 mm in thickness with only aerated lung normally posterior to it (white arrow).
- 4—Aortopulmonary Window Level,
Axial (A) and Coronal Views (B). (A) At this level you should be able to identify the trachea (T), ascending (AA) and descending aorta (DA), superior vena cava (S), and possibly the uppermost aspect of the left pulmonary artery (P). In most people, there is a space visible just under the arch of the aorta and above the pulmonary artery called the aortopulmonary window (white arrow). (B) Coronal reformatted CT enables us to also see the right atrium (RA), superior vena cava (S), pulmonary artery (P), left ventricle (LV), aortic valve (black arrow), left atrial appendage (white arrow), and origin of the great vessels (white circle).
- 5—Aortic Arch Level.
(A) Mediastinal window and (B) lung window. (A) At this level, you should be able to identify the aortic arch (AA), superior vena cava (S), and azygos vein (A). The white arrow points to air in the esophagus. (B) The same image as (A), but windowed to better visualize lung anatomy. Lung windows are chosen to maximize our ability to image abnormalities of the lung parenchyma and to identify normal and abnormal bronchial anatomy. T, Trachea.
- 6—Five-Vessel Level.
At this level, you should be able to identify the lungs, the trachea (T) and the esophagus (white arrow). Depending on the exact level of the image, several of the great vessels will be visible. The right brachiocephalic vein (R) is the vessel to the right of the trachea (T). The left brachiocephalic vein (L) lies just posterior to the sternum. From the patient’s right to the patient’s left, the arteries you see may include the innominate artery (I), left common carotid (C), and left subclavian arteries (S).
- 7—CT Coronary Angiogram, Left Anterior Descending (LAD) Coronary Artery.
The LAD (white arrow) travels in the anterior inter- ventricular groove and continues to the apex of the heart. It supplies most of the left ventricle and also the AV-bundle. Ao, Aorta; IVS, inter- ventricular septum; LV lumen, left ventricular lumen; RV, right ventricle.
- 8—CT Coronary Angiogram, Left Coronary Artery.
The left coronary artery (LCA) arises from the left coronary cusp at the aortic valve. It divides almost at once into the circumflex artery (white arrow) and left anterior descending artery (LAD) (black arrow). Ao, Aorta; LA, left atrium; RVOT, right ventricular outflow tract; SVC, superior vena cava.
- 9—Usual Interstitial Pneumonia (UIP).
An axial CT scan of the chest shows abnormalities at the lung bases, in a subpleural location, the typical distribution for UIP. There are small cystic spaces called honeycombing (white ovals) with evidence of bronchiectasis, as mani- fest by thickened bronchial walls (dotted white arrows).
- 10—Nonspecific Interstitial Pneumonia (NSIP).
A ground-glass opacity is seen in a subpleural location on the right (white circle). Ground- glass opacities are nonspecific abnormal areas of the lung that have increased attenuation (are whiter) in which the vascular markings and bronchi mostly appear intact. They can be associated with both benign and malignant diseases. Also present is bronchiectasis in both lungs (white arrows). The patient was known to have scleroderma
- 11—Metastases to the Lung, CT Scans.
(A) Multiple discrete nodules of varying size appear throughout both lungs (white arrows). The diagnosis of exclusion is metastatic disease whenever multiple nodules are found in the lungs. In this case, the metastases were from colon carcinoma.
- 12—Metastases to the Lung, CT Scans
(B) The interstitial markings in the right lung are prominent (black oval), there are thickened septal lines (white oval), fluid in the fissure (white arrow), and lymphadenopathy (solid black arrow) representing lymphangitic spread of a bronchogenic carcinoma.
- 13—Metastases to the Lung, CT Scans
(C) In this case, the lung cancer has grown through the chest wall (white arrow) and invaded it by direct extension. The pleura usually serves as a strong barrier to the direct spread of tumor.
- 14—Miliary Tuberculosis.
Innumerable small, round nodules are present in this axial CT scan of the chest in a patient with miliary tuberculosis (white circle). At the start of the disease, the nodules are so small they are frequently difficult to detect on conventional radiographs. When they reach about 1 mm or more in size, they begin to become visible. Miliary tuberculosis represents the widespread hematogenous dis- semination of the tubercle bacillus.
- 15—atelectasis of the entire right lung
(solid black arrow) from an obstructing endobronchial lesion. The visceral and pari- etal pleura remain in contact with each other. Other mobile structures in the mediastinum, such as the trachea and right main bronchus (dotted black arrows), shift toward the atelectasis. The left lung over-expands and crosses the midline (solid white arrow)
- 16—a large right-sided pneumothorax.
Air (solid white arrow) interposes between the visceral (dotted white arrows) and parietal pleura, causing the lung to undergo passive atelectasis (solid black arrow). There is a chest tube in the right hemithorax (arrowhead) that had been removed from suction.
- 17—Effusion and Atelectasis in Balance.
There is a balance between a large pleural effusion (E) and atelectasis of the right lung (black arrow) so that there is no significant resultant shift of the mobile midline structures. The heart essentially remains in its normal position (white arrow). This combination of findings is highly suggestive of a central bronchogenic malignancy with a malignant effusion.
- 18—Compressive (Passive) Atelectasis
Axial CT scan of the chest showing only the left hemithorax demonstrates a large left pleural effusion (solid black arrow). The left lower lobe (dotted black arrow) is atelectatic, having been compressed by the pleural fluid surrounding it.
- 19—Round Atelectasis, Left Lower Lobe.
A mass-like density is seen in the left lower lobe (dotted black arrow). The patient has underly- ing pleural disease in the form of pleural plaques from asbestos exposure (solid black arrows). Comet-tail shaped bronchovascular markings emanate from the “mass” and extend back to the hilum (solid white arrow). This combination of findings is characteristic of round atelectasis and should not be mistaken for a tumor
- 20—Small Pleural Effusion Seen on CT.
Here a small right pleural effusion (white arrows) collects in the dependent portion of the hemi- thorax (the patient is supine in the CT scanner). This effusion would probably not be visible on conventional chest radiographs as it would be obscured by the liver (L) on the frontal projection and the spine (S) on the lateral projection.
- 21—Large Hemothorax on CT.
A large fluid collection (F) on the right is causing complete compressive atelectasis of the right lung (solid white arrow) and a shift of the heart away from the side of the collection (dotted white arrow). On careful inspection, the fluid is denser (whiter) at the bottom of the collection (solid black arrows) than at the top, a fluid-fluid level that raises suspicion for the separation of blood products as would occur in a hemothorax. This patient was bleeding heavily from a lacerated intercostal artery.
- 22—Cavitary Pneumonia.
A nonenhanced axial CT image through the upper lobes demonstrates bilateral airspace disease (solid white arrows) containing multiple lucencies representing cavities (dotted white arrows). The cavities contain no air-fluid levels. Upper lobe cavitary pneumonia is presumptively tuberculosis (TB), until proved otherwise. This patient had postprimary TB (reactivation tuberculosis).
- 23—Aspiration, Both Lower Lobes.
Single, axial CT image of the lungs demonstrates bilateral lower lobe airspace disease (black arrows) in a patient who had aspirated. Aspiration usually affects the most dependent portions of the lung. In the upright position, the lower lobes are affected. In the supine position, the superior segments of the lower lobes and the posterior segments of the upper lobes are most involved. Aspiration of water or neutralized gastric acid will usually clear in 24 to 48 hours, depending on the volume aspirated.
- 24—CT of a Substernal Thyroid Goiter
Without and With Contrast Enhancement. (A) Before administration of intravenous contrast, this substernal thyroid mass (solid white arrow) is well-defined and contains coarse calcifications (dotted white arrow). (B) After contrast administration and at the same level as before, the goiter avidly takes up intravenous contrast, frequently with a mottled appearance (solid white arrow). This mass is displacing the trachea (T) slightly to the left.
- 25—CT of Anterior Mediastinal Adenopathy in Hodgkin Lymphoma.
On CT, lymphadenopathy will produce multiple, lobulated soft- tissue masses or a large soft-tissue mass from lymph node aggregation (white arrows). The mass is usually homogeneous in density, as in this case. The superior vena cava (SVC) is compressed, but not occluded, by the nodes. A, Ascending aorta; Ao, descending aorta.
- 26—Thymoma
Contrast-enhanced CT scan confirms the anterior mediastinal location and homogeneous density of the mass (white arrow). Most thymomas are benign. The patient had myasthenia gravis and improved following resection of the thymoma. A, Ascending aorta; Ao, descending aorta; PA, main pulmonary artery; SVC, superior vena cava.
- 27—Mediastinal Teratoma.
The most common variety of teratoma is cystic, which usually produces a well-marginated mass near the origin of the great vessels. On CT, they characteristically contain fat (solid black arrow), cartilage, and sometimes bone (dotted white arrow). They are usually benign, well-encapsulated with an enhancing rim, as in this case (solid white arrows). Treatment is surgical excision.
- 28—a large neurofibroma
that is enlarging the neural foramen, eroding half of the vertebral body (solid black arrow) and producing a dumb-bell shaped lesion that arises from the spinal canal, but projects through the foramen into the mediastinum (dotted white arrow).
- 29—SPN
solid
- 30—SPN
ground glass
- 31—SPN
partly solid, partly ground glass
- 32—Bronchogenic Carcinoma with Lymphangitic Carcinomatosis.
Seen is extensive hilar and mediastinal adenopathy (solid black arrows) from a carcinoma of the lung. The interstitial markings are prominent in the right lung compared with the left and there are thick- ened interlobular septa (Kerley B lines) present (solid white arrows) along with a right pleural effusion (dotted black arrow). Adenocarcinomas are the most common cause of lymphangitic carcinomatosis. Tumor cells can usually found in the lymphatics and pleural fluid.
- 33—Hampton’s Hump.
A wedge-shaped, peripheral air-space density present (dotted white arrow) is associated with filling defects in both the left and right pulmonary arteries (solid white arrows). The wedge-shaped infarct is called Hampton’s hump. Without the associated emboli being present, the peripheral airspace disease could have a differential diagnosis that includes pneumonia, lung contusion or aspiration.
- 34—Saddle pulmonary embolus
- 35—Peripheral pulmary embolus
- 36—Centriacinar (centrilobular) emphysema
is the most common type. Centrilobular emphysema has a strong association with cigarette smoking. It features focal destruction limited to the respiratory bronchioles and the central portions of the acinus (white arrows). It is most severe in the upper lobes.
- 37—Panlobular (panacinar) emphysema
involves the entire alveolus distal to the terminal bronchiole; it is most severe in the lower lung zones and generally develops in patients with homozygous alpha 1-antitrypsin deficiency, although it can also be seen in smokers and the elderly. This patient addition- ally has partial visualization of a nodular liver from cirrhosis (black arrows).
- 38—Paraseptal emphysema
involves distal airway structures, alveolar ducts, and sacs. It tends to occur around the septae of the lungs or subpleural surfaces.
- 39—Multiple, thin-walled bullae
are demonstrated by CT (dotted white arrows). Characteristically, they contain no blood vessels, but there may be septae that appear to traverse the bulla. Bullae may slowly increase in size and are associated with pneumothorax. If large and compromising the remainder of more normal lung, they can be surgically resected.
- 40—Cysts (Pneumatoceles)
in Pneumocystis Pneumonia (PCP). Cysts are visible on chest radiographs in 10% of patients with PCP and far more frequently with CT scans (up to 1 of 3 patients). They may occur in the acute or in the postinfective phase of the disease. They have a predilection for the upper lobes and are commonly multiple (white arrows). Their etiology is unclear.
- 41—Bronchiectasis: CT.
(A) The key sign in bronchiectasis is the signet ring sign in which the bronchus with a thickened wall (solid white arrow) becomes larger than its associated pulmonary artery (dotted white arrow). (B) The bronchus may also show tram-tracking, thickened walls, and a failure to taper normally (solid white arrows). An absence of the normal tapering of the bronchi is one of the most sensitive signs on CT. Cylindrical or tubular bronchiectasis, such as this, is the least severe of several types of bronchiectasis
- 42—Congestive Heart Failure: CT.
This is an axial CT scan of the chest following intravenous injection of contrast. Note that the right side of the heart is opacified, but the contrast has not yet passed through the lungs a sufficient number of times to fully opacify the left side of the heart. Bilateral pleural effusions are present and they layer posteriorly because the patient is being scanned supine (solid black arrows). Fluid has insinuated itself into the fissure (dotted black arrow). The thickened interlobular septae (solid white arrows) are Kerley B lines. LV, Left ventricle; RV, right ventricle.
- 43—hypertensive CVD
demonstrates marked concentric hypertrophy of the left ventricular wall (white and black arrows) that has occurred at the expense of the lumen (LV).
- 44—mitral stenosis
This is a contrast-enhanced axial CT image through the heart. The left atrium (LA) is markedly enlarged in this patient because of the obstruction of outflow from the left atrium by the stenotic mitral valve. Eventually, the increase in left atrial pressure is transmitted backward through the pulmonary venous and then pulmonary arterial circulations. Ao, Aorta; RA, right atrium.
- 45—Pulmonary Arterial Hypertension. Normally, the main pul- monary artery (MPA) is about the same diameter as the ascending aorta (A). In this patient, with pulmonary arterial hypertension, the MPA is much larger than the aorta. There is also a rapid attenuation in the size of the pulmonary arteries (white arrows) called pruning, another feature of pulmonary arterial hypertension. This patient had a history of chronic pulmonary thromboembolic disease.
- 46—Poststenotic dilatation
This unenhanced axial CT scan of the heart shows dense calcification of the aortic valve (black arrow) and a markedly thickened left ventricular wall (double white arrows) from hypertrophy. LV, Left ventricular lumen.
- 47—Constrictive Pericarditis.
There is extensive pericardial calcification (white arrows), most likely postinflammatory in etiology in this patient. Although restrictive cardiomyopathy and constrictive peri- carditis can have identical clinical findings, the presence of pericardial calcifications excludes restrictive cardiomyopathy. If indicated, pericar- diectomy holds the potential for cure for constrictive pericarditis.
- 48—aortic aneurysm
he aneurysm measured 6.7 cm, which placed it at significant risk for rupture. Calcification in the wall of an aneurysm is common (dotted white arrow). Contrast material mixes with blood flowing in the lumen of the aorta (solid white arrow), but the flowing blood is separated from the intimal calcification by a considerable amount of noncontrast-containing thrombus adherent to the wall (black arrow).
- 49—Aortic Dissections:
Types A and B. (A) An intimal flap is seen to traverse both the ascending (solid black arrow) and descending aorta (dotted black arrow). This is a Stanford type A dissection because of its involvement of the ascending aorta. (B) In another patient, there is a normal-appearing ascending aorta (dotted white arrow) and an intimal flap noted by the black line traversing the descending aorta (solid black arrow). An intimal flap is the characteristic lesion of an aortic dissection. The smaller lumen is usually the true (original) lumen and the larger, false lumen, is actually a channel that has been produced by blood dis- secting through the media.
- 50—Pancreatitis Producing Focal Bowel Dilatation.
Although the cause of a sentinel loop can usually only be inferred from conven- tional radiographs, CT scans can depict the underlying abnormality pro- ducing the bowel irritation. In this contrast-enhanced, axial CT scan of the upper abdomen with oral contrast, the pancreas is inflamed, enlarged, and edematous (white arrows) and there is haziness of the peripancreatic fat. The inflammation can affect peristalsis in adjacent loops of small bowel (SB) and lead to dilatation of the loops.
- 51—Small Bowel Obstruction From Inguinal Hernia.
(A) The scout image from a CT scan of the abdomen reveals dilated loops of small bowel (solid black arrow) caused by a left inguinal hernia (white circle). Loops of bowel should normally not be present in the scrotum. (B) Coronal-reformatted CT scan on another patient shows multiple fluid-filled and dilated loops of small bowel (solid white arrows) from an inguinal hernia (white circle) containing another dilated loop of small bowel (dotted white arrow).
- 52—Partial Small Bowel Obstruction.
Coronal-reformatted CT scan with oral contrast shows dilated and contrast-containing loops of small bowel (solid white arrows). Although air is seen in the collapsed colon (dotted white arrows), the disproportionate dilatation of small bowel identifies this as a small bowel obstruction.
- 53—Small Bowel Obstruction Caused by a Spigelian Hernia.
A Spigelian hernia is one that occurs at the lateral edge of the rectus abdominis muscle at the semilunar line. This patient has a transition point (solid white arrow) as the small bowel enters the hernia (dotted white arrow). More proximally, there are multiple dilated loops of small bowel (solid black arrows) indicating obstruction. The colon lies beyond the point of obstruction and is collapsed (dotted black arrow).
- 54—Small Bowel Obstruction: CT With Oral and Intravenous Contrast.
There are multiple fluid- and contrast-filled, dilated loops of small bowel (solid black arrows) and a collapsed colon (solid white arrows), indicating a small bowel obstruction. Bowel wall enhancement or lack thereof may be obscured by oral contrast, a drawback to the use of oral contrast. Incidentally noted is a right renal cyst (dotted black a
- 55—Small Bowel Feces Sign.
Air is mixed with debris and old oral contrast in a dilated loop of small bowel (solid white arrows). There are proximal fluid-containing, dilated loops of small bowel (dotted white arrows). The patient had a CT scan with oral contrast several days earlier for abdominal pain and returned for this noncontrast scan when symptoms persisted. Intestinal debris and fluid may accumulate in the loop found just proximal to a small bowel obstruction and present with this finding, which resembles fecal mate- rial in the colon.
- 56—Closed-Loop Obstruction, CT Lower Abdomen.
A loop of small bowel (CL) is obstructed twice at the same point of a twist (solid white arrow) producing a closed loop. No oral contrast enters the closed- loop, but is present in a more proximal loop of small bowel (dotted white arrow). Closed-loop obstructions are important because of their higher incidence of bowel necrosis from strangulation of the bowel.
- 57—Bowel Necrosis: Contrast-Enhanced CT.
A dilated loop of small bowel demonstrates faint, but normal enhancement of the wall (white arrow) on this coronal reformat of a contrast-enhanced CT, whereas more distal, dilated loops of small bowel show no wall enhancement (black circle). The lack of enhancement is an indication of vascular com- promise of the distal loops with bowel necrosis.
- 58—Large Bowel Obstruction: CT.
Two CT images from the same patient demonstrate (A) dilated and fluid-filled loops of large bowel (white arrows). The orally administered contrast had not yet reached the large bowel at the time of this study, but does fill loops of small bowel. A large soft-tissue mass in the sigmoid (dotted white arrow) represents the patient’s obstructing carcinoma of the sigmoid colon (B).
- 59—Large Bowel Obstruction From Carcinoma of the Colon.
This coronal reformatted CT scan of the abdomen and pelvis shows a dilated cecum containing stool (dotted white arrow) and dilated large bowel (LB) to the level of the distal descending colon where a large soft-tissue mass is identified (solid white arrow). This mass was surgically removed; it was an adenocarcinoma of the colon.
- 60—Small Amount of Free Air, CT.
Axial CT scan of the upper abdomen performed with the patient supine shows a very small collec- tion of free air beneath the anterior abdominal wall (solid white arrows). Characteristically, free air has no surrounding bowel wall, as does air within bowel loops (dotted white arrows). This amount of free air was not visible on conventional radiographs.
- 61—falciform ligament sign
On CT, the falciform ligament (white arrow) is outlined by free air (FA) on either side of it, anterior to the liver (L)
- 62—Extraperitoneal Air Seen on CT.
Air is seen in the retro- peritoneum (solid black arrow) on this axial CT scan of the upper abdomen. Air outlines the inferior vena cava (solid white arrow) and the aorta (dotted white arrow). Unlike free air, extraperitoneal air is streaky, rela- tively fixed in position, and outlines extraperitoneal structures.
- 63—Pneumatosis Cystoides Intestinalis.
Axial CT scan of the upper abdomen windowed for lung technique shows a cluster of air- containing cysts (solid white arrows) associated with the left colon, characteristic of pneumatosis cystoides intestinalis, a rare condition of unknown etiology. The cysts are usually subserosal or submucosal in location and the patient is often asymptomatic.
- 64—portal venous gas
Close-up of axial CT scan through the liver shows air in the portal venous system (white arrows) in a patient with mesenteric vascular disease.
- 65—Necrosis of Bowel from Mesenteric Ischemia.
Axial CT image of the pelvis demonstrates multiple loops of bowel with curvilinear collections of air throughout their walls consistent with pneumatosis (white arrows). The patient had widespread ischemia of bowel from mesenteric vascular disease. Pneumatosis that results from bowel necrosis is an ominous sign.
- 66—Gallstone Ileus.
The three key findings of gallstone ileus are present on this study. (A) Axial CT scan of the upper abdomen shows air in the lumen of the gallbladder (black arrow) and dilated small bowel (white arrow), which is consistent with a mechanical small bowel obstruction. (B) At a lower level, another axial CT scan of the abdomen shows a large calcified gallstone inside the small bowel (dotted white arrow) and additional proximal, dilated loops of small bowel (solid white arrow).
- 67—Renal calculi
unenhanced axial CT called a “stone search” reveals a large calcification in the proximal right ureter (black arrow) and several smaller calcifications in the left intrarenal collecting system (white arrow). Because of its greater sensitivity, a CT stone search done without intravenous contrast has mostly replaced conventional radiography for the iden- tification of renal and ureteral calculi.
- 68—gall stones
- 69—urinary bladder stones
- 70—chronic calcific pancreatitis
- 71—calcified leiomyoma (with necrosis)
- 72—calcified ovarian metastases
- 73—Perforated Duodenal Ulcer.
Axial CT scan of the upper abdomen done with oral and intravenous contrast shows a tract of extraluminal oral contrast (solid white arrow) originating from the duo- denum into the peritoneal cavity (dotted white arrow). The patient had a perforated duodenal ulcer repaired at surgery.
- 74—Key Findings on CT of the GI Tract. These are findings applicable to any part of the bowel that are key to the diagnosis of bowel abnormalities on CT. (A) There is thickening and enhancement of the wall of the bowel (white circle). When distended, as these loops of large bowel are, the bowel wall is normally very thin, no greater than 3 mm. The small bowel wall is also usually no thicker than 3 mm.
- 75—Submucosal infiltration is producing irregularity of the wall (white arrow). In this case of ischemic colitis, it most likely represents edema with some hemorrhage.
- 76—(C) There is infiltration of the surrounding fat (dotted white arrow), a sentinel finding that usually heralds adjacent inflammation. There is also extraluminal air (white circle), a sign of bowel perforation.
- 77—diverticula
contain air and appear as small, usually round outpouchings, especially in the region of the sigmoid colon (white oval)
- 78—Diverticulitis: CT.
Infiltration of the pericolonic fat is demonstrated by a hazy increase in attenuation (white arrow) of the normal fat. Focal infiltration of fat is a common characteristic of inflammatory disease
- 79—Diverticulitis
There is a large abscess cavity (A) in the left lower quadrant in this close-up of a CT scan of the lower abdomen. There are adjacent small bubbles of extraluminal gas and infiltration of the normal fat (dotted white arrow). These findings are secondary to a confined perforation with abscess formation from diverticulitis.
- 80—intussusception
- 81—Colitis.
The colon demonstrates thumbprinting, nodular indentations on the lumen (white arrows), and an overall pattern that is called the accordion sign
- 82—appendicitis
- 83—appendicolith
- 84—lower GI bleed
Axial image of the pelvis after intravenous, but no oral, contrast shows an amorphous collection of contrast in the lumen of the cecum (white circle), representing extravasated blood
- 85—lower GI bleed
Coronal reconstruction on the same patient demonstrates several collections of intraluminal contrast in the cecum (white circle). The white arrows on both images identify opacified iliac arteries. The patient was bleeding from a vascular malformation of the cecum. AC, Ascending colon.
- 86—acute pancreatitis
- 87—pancreatic pseudocyst
A pseudocyst (P) of the pancreas is a collection of fluid, usually high in pancreatic enzymes, outside of the pancreas and enclosed by a wall of fibrous and granulation tissue. The wall may contrast-enhance (white arrows). The cyst is indenting a loop of adjacent bowel, in this case the posterior wall of the stomach (S). The type of indentation on a loop of bowel by an extrinsic mass, whatever its origin, is called a pad sign (black arrow)
- 88—Pancreatic Adenocarcinoma.
The head of the pancreas is enlarged by a mass (white arrow). Normally, the head of the pancreas should roughly be the same size as the width of the lumbar vertebral body nearest to it. The symptoms of pancreatic adenocarcinomas are frequently vague, laboratory findings are nonspecific, and pancreatic adenocarcinomas are difficult to image, especially in patients with con- comitant changes of chronic pancreatitis.
- 89—Triple-Phase CT Scan of the Liver: Hepatocellular Carcinoma.
Evaluation of liver masses is usually done with a combination of scans, including an unenhanced scan (A) and then two postcontrast scans: one obtained quickly (B), called the hepatic-arterial phase, and a second about a minute later (C), called the portal-venous phase. This case shows the typical findings of a focal hepatocellular carcinoma. Most are low density (hypodense) or the same density as normal liver (isodense) without contrast (white arrow in A), enhance on the arterial phase with intravenous contrast (hyperdense) (dotted arrow in B) and then return to hypodense or isodense on the venous phase (dashed arrow in C).
- 90—diffuse fatty liver
- 91—Cirrhosis, Portal Hypertension, and Varices: CT.
(A) The spleen (S) is enlarged from portal hypertension secondary to cirrhosis. There is characteristic enlargement of the caudate lobe (C) relative to the right lobe of the liver (black arrow). Several contrast-enhanced dilated veins (varices) are seen around the stomach and splenic hilum (white arrows). (B) Another patient shows the typical nodular and shrunken appearance of the cirrhotic liver (white arrows) along with numerous contrast-enhanced, periesophageal varices (white circle). Ao, Descending aorta
- 92—Differentiating Pleural Effusion from Ascites.
(A) Patients may have a combination of ascites and pleural effusions for a number of reasons, cirrhosis being one of them. Ascitic fluid (As) will appear anterior to the hemidiaphragm (white arrow) in the axial plane. Pleural effusion (P) will be located posterior to the hemidiaphragm. (B) Ascites will never completely encircle the dome of the liver because of the “bare area” (black arrow), not covered by peritoneum (see Fig. 14.2). Fluid posterior to the bare area must be in the pleural space (P).
- 93—metastases to liver and spleen
- 94—Diffuse Hepatocellular Carcinoma of the Liver: CT.
The three major patterns of appearance for hepatocellular carcinoma are solitary mass, multiple nodules, and diffuse infiltration throughout a segment or lobe (as in this case) or the entire liver. (A) A typical low-attenuation lesion is seen in the right lobe of the liver on the unenhanced scan (white arrow). (B) The arterial phase demonstrates patchy enhancement (black arrow) indicating the probability of tumor necrosis in the low-attenuation areas. Ascites is present (As). The overall volume of the liver is decreased and the contour is lobulated from underlying cirrhosis.
- 95—Cavernous Hemangioma of the Liver: Triple-Phase CT Study.
(A) Cavernous hemangiomas (white arrows on all images) are usually hypodense lesions on unenhanced scans. (B) They characteristically enhance from the periphery inward following injection of intravenous contrast during the arterial phase and eventually become isodense. (C) Contrast then tends to be retained within the numerous vascular spaces of the lesion so that they characteristically appear denser than the rest of the liver on delayed scans.
- 96—Hepatic Cysts: CT.
Believed to be congenital in origin, hepatic cysts are easily identified as sharply marginated lesions of low attenuation (fluid density) compared with the remainder of the liver, on both unenhanced and enhanced CT scans. MRI is much better than CT at characterizing cysts. They are usually solitary and are homo- geneous in density (black arrows)
- 97—renal cyst
- 98—renal cell carcinoma
- 99—transitional cell carcinoma of bladder
- 100—massive lymphadenopathy d/t lymphoma
- 101—pneumothorax with subcutaneous emphysema
- 102—pneumothorax with pleural adhesions
- 103—bullous disease right, pneumothorax left
- 104—pulmonary contusion with multiple rib fractures
- 105—pulmonary laceration
f they are partially filled with blood and partially filled with air, they may contain a visible air-fluid level (black arrow). Unlike the neighboring pulmonary contusion (solid white arrow), pulmonary lacerations may take weeks or months to clear com- pletely, especially if they are blood filled. The top of the left hemidiaphragm (D) is seen in this image.
- 106—pulmonary interstitial edema
Pulmonary Interstitial Emphysema. This coronal reformat- ted CT scan of the chest demonstrates air (solid white arrows) sur- rounding the pulmonary arteries (white branching structures) in the lung. This air arose from a ruptured alveolus in a patient with asthma and is tracking back to the hilum where it also produced pneumomediastinum and subcutaneous emphysema. The patient also has bilateral basilar pneumothoraces (dotted white arrows).
- 107—pneumomediastinum with continuous diaphragm sign
- 108—Aortic Trauma: Three Different Patients.
(A) There is a tear at the level of the aortic isthmus represented by the linear defect in the wall of the descending aorta (solid white arrow). A mediastinal hema- toma is also present (dotted white arrows). (B) There is a large mediastinal hematoma (solid white arrows). (C) There are periaortic hematomas containing extravasated blood (black arrows) and a large mediastinal hematoma (solid white arrows). AA, Ascending aorta; AR, aortic arch; DA, descending aorta; PA, pulmonary artery.
- 109—Hepatic Trauma: Three Different Patients. (A) There is a lenticular fluid collection involving the lateral portion of the right lobe of the liver that represents a subcapsular hematoma (solid black arrow). There is also a laceration of the right lobe (dotted black arrow). (B) There are multiple lacerations of the right lobe of the liver (black circle). (C) There is active extravasation of contrast-enhanced blood (solid black arrow) from a large intrahepatic laceration with hematoma (dotted black arrow) and both subcapsular blood and hemoperitoneum (solid white arrow).
- 110—Splenic Trauma: Three Different Patients. (A) There is crescent-shaped collection of fluid in the subcapsular space, which compresses the normal splenic parenchyma, representing subcapsular hematoma (solid white arrow). (B) This patient has a splenic (solid white arrow) and hepatic (solid black arrow) lacera- tion and a large hepatic contusion (dotted black arrow). There is also pneumoperitoneum (dotted white arrow). (C) This patient has active extravasation of contrast-enhanced blood (solid black arrow) and a large intrasplenic hematoma (solid white arrow).
- 111—splenic contusions
- 112—Renal Trauma: Two Different Patients.
(A) Coronal-reformatted, contrast-enhanced CT scan shows a low-attenuation linear defect representing a renal laceration (black arrow) and a subcapsular hematoma (white arrow). (B) Axial CT scan of another patient also shows a renal laceration (solid black arrow) and a perinephric hematoma (dotted black arrow).
- 113—tear of proximal ureter
- 114—shock bowel
- 115—bladder rupture extraperitoneal and intraperitoneal
- 116—Ruptured Diaphragm.
(A) There is a rent in the right hemidiaphragm that allows a portion of the liver (HL) to extrude through the rupture. Where the organ passes through the rupture, a constricted zone is seen (black arrows) called the collar sign. (B) The sagittal view demonstrates the herniated portion of the liver (dotted white arrow). HL, Herniated portion of liver; L, liver.
- 117—pancreatic laceration
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- Physician Assistant Diagnostic Imaging Karteikarten am Exam 2- CT, erstellt von Ava Retsch am 08/09/2022.
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