Evaluation of the lower extremity veins in patients with suspected pulmonary embolism: a retrospective comparison of helical CT venography and sonography. 2000 ARRS Executive Council Award I. American Roentgen Ray Society.

OBJECTIVE: In patients undergoing a combined CT angiographic and CT venographic protocol, the accuracy of helical CT venography for the detection of deep venous thrombosis was compared with that of lower extremity sonography. MATERIALS AND METHODS: Patients who had undergone a combined CT angiographic and CT venographic protocol and sonography of the lower extremities within 1 week were identified. The final reports were evaluated for the presence or absence of deep venous thrombosis. Statistical measures for the identification of deep venous thrombosis with helical CT venography were calculated. In each true-positive case, the location of the thrombus identified with both techniques was compared. All false-positive and false-negative cases were reviewed to identify the reasons for the discrepancies. RESULTS: Seventy-four patients were included. There were eight patients (11%) with true-positive findings, 61 patients (82%) with true-negative findings, four patients (5%) with false-positive findings, and one patient (1%) with a false-negative finding. When comparing helical CT venography with sonography for the detection of lower extremity deep venous thrombosis, the sensitivity measured 89%; specificity, 94%; positive predictive value, 67%; negative predictive value, 98%; and accuracy, 93%. Of the eight true-positive cases, five had sites of thrombus that were in agreement on both CT venography and sonography. Of the five discordant cases, four were false-positives and one was a false-negative. Possible explanations for all discrepancies were identified. CONCLUSION: Compared with sonography, CT venography had a 93% accuracy in identifying deep venous thrombosis. However, the positive predictive value of only 67% for CT venography suggests that sonography should be used to confirm the presence of isolated deep venous thrombosis before anticoagulation is initiated. In addition, interpretation of CT venography should be performed with knowledge of certain pitfalls.

Lung volumes before and after lung volume reduction surgery: quantitative CT analysis.

The volume and severity of pulmonary emphysema in individual lungs were measured by means of quantitative computed tomography (CT) studies in 28 patients (14 women, 14 men, median age 65 yr) who underwent either bilateral (n = 15) or unilateral (n = 13) lung volume reduction surgery (LVRS). Spirometric, total body plethysmographic, and CT data (at TLC and RV) were correlated before and after LVRS. Lung volumes determined by CT correlated well with volumes obtained by total body plethysmography (p < 0.0001). For individual lungs after LVRS, CT-derived mean lung capacity decreased 13% and residual volume 20% (p < 0.00001 for each), while mean total functional lung volume (TFLV, defined as the volume of lung with CT attenuation greater than -910 Hounsfield units) increased 9% (p < 0.01), and the mean ratio of the air space to tissue space volume (V(AS)/V(TS)) decreased more at RV (23%) than at TLC (14%) (p < 0.0005 for each). In contrast, unilateral LVRS did not affect exhalation from the unoperated lung (2% reduction in RV, p = NS). The magnitude of the postoperative response (CT-derived TLC, RV, TFLV, V(AS)/V(TS)) of each operated lung was comparable for unilateral and bilateral LVRS. Thus, a lung's response to LVRS was independent from that of the contralateral lung. Moreover, postoperative alterations in TFLV and FEV1 correlated significantly (r = 0.80, p < 0.0001), which suggests that the expansion of functioning tissue may contribute to the mechanism by which LVRS palliates airway obstruction.

Opportunistic bronchopulmonary infections after lung transplantation: clinical and radiographic findings.

PURPOSE: To assess clinical and radiographic findings in opportunistic bronchopulmonary infections after lung transplantation. MATERIALS AND METHODS: Forty-five episodes of opportunistic bronchopulmonary infection occurred in 27 (35%) of 77 lung transplant recipients during a 4-year period. Causative organisms, radiographic patterns, and mortality were reviewed. RESULTS: Cytomegalovirus (CMV) was the most common pathogen (25 episodes), followed by Aspergillus species (seven episodes), Pneumocystis carinii (six episodes), herpes simplex virus (four episodes), Mycobacterium avium complex (two episodes), and M tuberculosis (one episode). Eighteen of the 25 episodes (72%) of CMV pneumonitis occurred in the first 4 months after transplantation; 24 (96%) occurred within the 1st year. Radiographic patterns of symptomatic CMV pneumonitis were diffuse haziness (60%), focal haziness (33%), and focal consolidation (7%). Aspergillus species locally invaded a necrotic bronchial anastomosis in three patients, each within 4 months of transplantation. P carinii was seen as focal haziness and caused no symptoms. Radiographic findings, when present, were seen almost exclusively in the transplanted lung. Despite three deaths attributable to opportunistic bronchopulmonary infection, the difference between the survival rates of patients with and those of patients without bronchopulmonary infection was not statistically significant (82% and 81%, respectively, 1 year after transplantation). CONCLUSION: Opportunistic bronchopulmonary infections are common after lung transplantation. The most common pathogen is CMV, which causes diverse chest radiographic patterns. Opportunistic bronchopulmonary infections do not adversely affect overall mortality.

Pulmonary Gaucher's disease: high-resolution computed tomographic features.

CT findings in pulmonary Gaucher's disease have not been previously reported. Chest radiograph of a patient with pulmonary involvement in type I Gaucher's disease proven by biopsy showed linear and reticulo-nodular opacities. High-resolution CT demonstrated thickening of the interlobular septa and between four and six small nodules within secondary lobules, probably each corresponding to an acinus.

Thoracic involvement in Behçet's disease: pathologic, clinical, and imaging features.

Behçet's disease is a rare form of vasculitis of obscure etiology. Any large or small artery, vein, or organ may be involved in an unpredictable combination. Intrathoracic manifestations of Behçet's disease consist mainly of thromboembolism of the superior vena cava and/or other mediastinal veins; aneurysms of the aorta and pulmonary arteries; pulmonary infarct and hemorrhage; pleural effusion; and, rarely, myocardial or pericardial involvement, cor pulmonale, and mediastinal or hilar lymphadenopathy. Chest radiography is the best diagnostic method for evaluating thoracic involvement in Behçet's disease. Because aneurysms may develop at the arterial puncture sites and veins may be quickly thrombosed after injection of contrast material, angiography and venography should be avoided whenever possible. Although no comparative studies are available, CT and MR angiography appear to be imaging techniques of choice for evaluating vascular involvement. Pulmonary parenchymal alterations depicted on CT scan have not been fully explored.

Accessory fissures of the upper lobe of the left lung: CT and plain film appearance.

OBJECTIVE: The purpose of this study was to assess CT and chest radiographic features of accessory fissures of the upper lobe of the left lung. MATERIALS AND METHODS: Eighteen accessory fissures of the upper lobe of the left lung were identified on CT scans of 17 adult patients. The collimation was 10 mm in 12 patients and 8 mm in five patients. Additional, thinner sections (1.5-5.0 mm) were available for 12 patients. The segments separated by each fissure were identified by means of the individual segmental bronchi and vessels. Available chest radiographs were correlated with CT studies in 12 patients. RESULTS: The fissures separated the anterior segment of the left upper lobe from the superior segment of the lingula (left minor fissure) in 13 cases (72%), the superior from the inferior segment of the lingula in three cases (17%), and the apico-posterior from the anterior segment in two cases (11%). Ten (56%) of the 18 fissures could be seen only on thin sections. Eleven (61%) of the accessory fissures were incomplete. The fissures were classified into four types: convex laterally (n = 8), convex medially (n = 2), anteromedial (n = 5), and transverse (n = 3). On posteroanterior chest radiographs, the accessory fissure was evident in 10 (83%) of 12 patients. CT studies showed that nine of the 10 fissures seen on radiographs represented a left minor fissure, and the remaining fissure separated the two segments of the lingula. CONCLUSION: Accessory fissures of the upper lobe of the left lung, as shown by CT, can separate any two contiguous segments, are frequently incomplete, and occur in four different configurations. The left minor fissure is the most common of these fissures and the most frequently seen on chest radiographs. The ability to recognize accessory fissures of the left upper lobe should help in the segmental and topographic localization of pulmonary lesions.

Intersegmental (intersublobar) septum of the lower lobe in relation to the pulmonary ligament: anatomic, histologic, and CT correlations.

A thin horizontal linear area of hyperattenuation that extends laterally from the mediastinal surface of the lung within the area between the inferior pulmonary vein and the diaphragm is a common observation on computed tomographic (CT) scans of the chest. To determine the anatomic basis for this structure, the authors examined four normal human lungs (two right and two left lungs) fixed in an inflated state at pathologic and histologic examination and at CT. The structure in question was identified in one right and two left lungs. The linear area of hyperattenuation seen at CT is a septum of thin, loose intraparenchymal connective tissue that is bounded medially by the base of the pulmonary ligament, where the two sleeves of the visceral pleura appose one another, and laterally by a vertically oriented vein. The septum was identified in 39 of 50 (78%) normal chest CT scans. The pulmonary ligament often appeared to look like a beak at the mediastinal side of the lung. The septum, when visible (n = 39), was bounded medially by the beak in 28 CT scans (72%) and laterally by a vein in 24 scans (62%).

Interleukin-2 therapy for advanced renal cell carcinoma: radiographic evaluation of response and complications.

To evaluate the radiographic manifestations of the response of intrathoracic metastases to and the toxicity of interleukin-2 (IL-2) therapy, the chest radiographs and computed tomographic scans of 43 patients receiving 103 cycles of IL-2 treatment and lymphokine-activated killer cells for advanced renal cell carcinoma were reviewed. Among these 43 patients, 31 could be assessed for response of metastatic disease: Complete response was seen in one (3%), partial response in 11 (36%), mixed response in nine (29%), progressive disease in five (16%), and stable disease in five (16%). In 103 treatment cycles radiographic evidence of toxicity included pleural effusions (45.6%), pulmonary edema (21.4%), increased cardiothoracic ratio (16.5%), increased azygos vein diameter (9.7%), pericardial effusion (5.8%), and hilar lymphadenopathy (1.0%). These toxic effects could be distinguished from metastatic disease by a temporal relationship to treatment cycles. A favorable response to IL-2 therapy was significantly correlated (P less than .001) with the presence of pleural effusions.

Pulmonary artery sarcoma: evaluation using Gd-DTPA.

Primary malignant tumors of the pulmonary arteries occur infrequently and diagnosis is often delayed since symptoms are nonspecific. We present a case of pulmonary artery sarcoma and its interesting magnetic resonance findings.

Torsion of the upper lobe in pneumothorax.

A rounded density is occasionally seen hanging down from the hilus in the presence of a large pneumothorax. To find an explanation for this appearance, the authors obtained a right-sided bronchogram on a baboon, after which they induced pneumothorax on the same side. This experiment demonstrated that the rounded density is formed by a twisted and atelectatic upper lobe.

Right phrenic nerve: anatomy, CT appearance, and differentiation from the pulmonary ligament.

The pulmonary ligament appears on computed tomographic (CT) sections as a thin, high-attenuation line, frequently seen above or at the level of the diaphragm and usually extending from the region of the esophagus. However, another line coursing laterally from the midportion of the inferior vena cava has also been identified as the pulmonary ligament. The authors examined sections from eight cadavers and 80 chest CT examinations to more clearly delineate the pulmonary ligament from this second structure. Anatomic and CT correlation proves that the line seen at the midportion of the inferior vena cava represents the right phrenic nerve and that the right pulmonary ligament is located posterior to it.

Anatomy of the minor fissure: evaluation with thin-section CT.

The minor fissure was studied with thin computed tomographic (CT) sections in 40 patients. It was absent in eight (20%) and seen in 32 (80%) patients; of these 32 the fissure was complete in seven (22%), incomplete in 23 (72%), and of indeterminate completeness in two (6%). Appearance of the minor fissure on CT scans can be categorized into two major configurations, which are determined by variation in contour of the middle lobe upper surface. The location of the highest point along this surface is either medial (type I configuration) or lateral (type II configuration). The lowest tributary of the vein draining the anterior segment of the upper lobe was seen in 75% of the patients. This vessel was a reliable landmark in delineating boundaries between upper and middle lobes, even when the fissure was radiologically incomplete or absent. In the authors' experience, familiarity with these configurations of the minor fissure has been useful in localization of a lesion in a lobe or determination of its possible extension beyond the fissure into the neighboring lobe.

Diagnosis of epiphrenic esophageal diverticulum by computed tomography.

Epiphrenic diverticulum is typically demonstrated by computed tomography examination as a thin walled, air or air-fluid filled structure communicating with the esophagus. However, those not associated with a distal esophageal obstruction (stricture, achalasia) may remain contracted in resting state and thus may not be visible. Occasionally the diverticulum may have to be differentiated from mediastinal abscess or tumors and even hiatus hernia.