Mixed infiltrative and obstructive disease on high-resolution CT: differential diagnosis and functional correlates in a consecutive series.

Fourteen of 400 consecutive patients having high-resolution computed tomography (HRCT) with expiratory images showed findings of infiltrative lung disease on inspiratory HRCT and air trapping on expiratory CT. Diagnoses included hypersensitivity pneumonitis, sarcoidosis, atypical infection, and pulmonary edema. The extent of infiltrative abnormalities and air trapping were correlated with pulmonary function tests (PFT) in 11 patients. PFT indicated a mixed pattern in five, an obstructive pattern in three, and a restrictive pattern in three. Forced expiratory volume (FEV) in 1 second/forced vital capacity (FVC) correlated significantly with the extent of air-trapping (r = 0.60; p = 0.05). The extent of infiltrative abnormalities correlated significantly and negatively with forced vital capacity (r = -0.82, p = 0.002), FEV1 (r = -0.59, p = 0.05), total lung capacity (TLC) (r = -0.67, p = 0.05), and DLCO (r = -0.75, p = 0.02). Findings of lung infiltration on inspiratory HRCT scans and air trapping on expiratory CT correlated respectively with PFT measures of restrictive and obstructive lung disease.

Inhomogeneous lung attenuation at thin-section CT: diagnostic value of expiratory scans.

PURPOSE: To determine the utility of expiratory scans for diagnosis of inhomogeneous attenuation on thin-section computed tomographic (CT) scans. MATERIALS AND METHODS: On the basis of clinical information and pulmonary function test results, disease in 53 patients with inhomogeneous attenuation on inspiratory scans was classified into four groups--infiltrative, airway, vascular, or mixed. Without knowledge of the diagnosis, inhomogeneous attenuation was classified as (a) ground-glass opacity due to infiltrative disease, (b) mosaic perfusion due to airway disease, or (c) mosaic perfusion due to vascular disease, and the degree of confidence was indicated. Each case was reclassified if necessary on the basis of expiratory scan findings. RESULTS: A correct diagnosis was made more often on the basis of both inspiratory and expiratory scans than on the basis of inspiratory scans alone (92% [49 of 53 patients] vs 79% [42 of 53], respectively [P < .05]). Accuracy increased from 81% (21 of 26) to 89% (23 of 26) in cases of infiltrative disease and from 84% (16 of 19) to 100% (19 of 19) in cases of airway disease. A correct interpretation with high confidence level was reached more often with expiratory scans than on the basis of inspiratory scans alone (92% [49 of 53] vs 45% [24 of 53], respectively [P < .0001]). The extent of air trapping correlated significantly with pulmonary function test results. With expiratory scans, the classification of inhomogeneous attenuation was changed in 15% (eight of 53) of cases and the confidence level was improved in 51% (27 of 53) (P < .0001). CONCLUSION: Expiratory scans significantly improved diagnostic accuracy in patients with inhomogeneous attenuation on inspiratory scans, and they helped in the diagnosis of diffuse lung disease.

Miliary lung disease after intravesical bacillus Calmette-Guérin immunotherapy.

Clinical and radiologic findings in a 73-year-old man who developed a systemic illness while receiving intravesical bacillus Calmette-Guérin (BCG) immunotherapy for bladder cancer are presented. Thin-section chest computed tomographic findings included a diffuse pattern of small nodules consistent with miliary disease. Potential mechanisms explaining the pulmonary disease resulting from intravesical BCG treatment include a hypersensitivity reaction or actual BCG infection of the lungs.

Computed tomography of pancreatic pseudocysts of the duodenum.

The findings of computed tomography (CT) in seven patients with pancreatic pseudocysts involving the duodenum are reported. Specific CT characteristics of duodenal wall involvement by the pseudocysts are tubular configuration of the pseudocyst, extending along the wall and conforming to the course of the duodenum (seven of seven), and abrupt flattening of the otherwise tubular or spherical pseudocyst at the border of the duodenal lumen (five of seven). The second part of the duodenum was involved in all cases; in some cases the first part of the duodenum was also involved (two of seven), and in others the pseudocyst extended to the third part of the duodenum (two of seven). All patients had other CT evidence of pancreatitis in addition to duodenal pseudocysts. CT findings are compared to other imaging methods and clinical and surgical findings. Patients with duodenal pseudocysts should be watched carefully for signs and symptoms of gastric outlet obstruction, since this was a prominent clinical problem in six of seven patients, and gastric outlet obstruction complicating suspected pancreatitis should alert to the possibility of duodenal pseudocyst.

Bronchogenic carcinoma: staging with MR compared with staging with CT and surgery.

Thirty-three patients suspected of having bronchogenic carcinoma were studied prospectively using magnetic resonance (MR). In this group, 30 underwent examination with computed tomography (CT), 15 underwent thoracotomy, six had mediastinal biopsy procedures performed, and eight underwent bronchoscopy. MR studies, which included transaxial spin-echo imaging (TR, 0.5 and 2.0 sec; TE, 28 and 56 msec) of all patients and sagittal or coronal imaging of 18, were performed without knowledge of CT findings, using only plain radiographs as a guide. CT and MR studies were interpreted separately. CT and MR provided comparable information regarding the presence and size of mediastinal lymph nodes. MR better discriminated mediastinal nodes from vascular structures. However, in two of 11 patients who had multiple mediastinal lymph nodes that were normal in size at CT examination and surgery, MR suggested a confluent abnormal mass, probably because of its poorer spatial resolution. MR was superior to CT in showing enlarged hilar lymph nodes, but CT was better for demonstrating bronchial abnormalities. In three of four patients who had a proved hilar mass with distal obstructive pneumonia, MR (TR, 2.0 sec) helped distinguish between the mass and collapsed lung.

CT of aortoenteric fistulas.

We compared CT findings with endoscopic, angiographic and surgical results in ten patients suspected of having an aortoenteric fistula (AEF) because of gastrointestinal bleeding (seven) or recurrent sepsis (three). CT correctly diagnosed AEF in six patients and excluded it in the other four. CT findings of AEF consisted of perigraft fluid (PGF) (5/6) and/or gas within the bed of the graft (4/6) later than three months after graft surgery. All six patients with AEF had perigraft infections; PGF with gas was found in 50%, PGF alone in 33%, and in one patient perigraft gas alone was found. Angiography and endoscopy failed to identify AEF. Our findings indicate that CT should be the initial imaging procedure in patients with suspected AEF who do not require immediate surgical intervention.