Computed tomography of the pulmonary hilum in patients with bronchogenic carcinoma.

In 30 patients with histologically proven bronchogenic carcinoma, computed tomographic (CT) scans of the pulmonary hila, plain radiographs, and medical records were reviewed. All had abnormal plain radiographs. The CT findings included (a) a local alteration in hilar contour; (b) thickening of the posterior wall of the right upper lobe bronchus, bronchus intermedius, or left main bronchus; and (c) narrowing, displacement, or obstruction of bronchi. In 24 patients having fiberoptic bronchoscopy, CT findings of bronchial abnormality correlated closely with bronchoscopic findings. In two patients, CT showed a bronchial abnormality invisible at bronchoscopy, leading to a positive biopsy. In one patient, a bronchial abnormality invisible at CT was visible at bronchoscopy and positive on biopsy.

Problems and pitfalls in the evaluation of thoracic aortic dissection by computed tomography.

Several conditions can lead to either false positive or false negative diagnoses of aortic dissection by computed tomography (CT) with intravenous administration of contrast medium. Insufficient contrast enhancement may cause intimal flaps to be missed, leading to a false negative diagnosis. False positive diagnoses result when extraaortic structures (e.g., mediastinal veins, pericardium, thickened pleura, and lung) are mistaken for false channels in the aorta. Superimposition of structures in thick CT slices may cause intimal calcifications to appear displaced. Streak artifacts across the descending aorta can resemble double aortic channels or intimal flaps. Fusiform aneurysms with thrombus are often hard to distinguish from thrombosed dissections by CT as well as by aortography.

Distinguishing benign from malignant pulmonary nodules by computed tomography.

Investigators have been able to distinguish benign pulmonary nodules from malignant ones in about two-thirds of the cases studied by detecting high computed tomography (CT) numbers (attributed to microscopic calcifications) within many benign nodules. This paper reports a similar analysis on a series of 22 benign and 14 malignant pulmonary nodules. Although about one-third of the benign nodules gave high CT numbers, all but one of the nodules diagnosed as benign by CT could also be diagnosed by detection of calcification on plain radiographs or conventional tomograms.

CT demonstration of mediastinal aortic arch anomalies.

Computed tomography (CT) can be helpful in the detection and diagnosis of aortic arch malformations, including anomalous right subclavian artery, left sided aortic arch with right descending aorta, right sided, aorta with anomalous left subclavian artery or mirror image branching, and double aortic arch. This paper reviews the CT findings in 10 such patients. Computed tomography can confirm the presence of an aortic anomaly suspected from plain radiographs or can detect a vascular anomaly when the plain radiograph suggests the presence of a mediastinal mass.

Alterations in CT mediastinal anatomy produced by an azygos lobe.

Computed tomographic (CT) scans of 11 patients with an azygos lobe were compared with similar scans of age- and gender-matched normal controls. The reflections of the right lung against the superior mediastinum were evaluated, and particular attention was directed to five specific areas: the azygos vein and arch, the superior vena cava, the pretracheal and retrotracheal areas, and the esophagus. With an azygos lobe, the azygos arch is at a more cephalad position than normal. The axis of the superior vena cava is oriented toward the left. The azygos lobe intrudes into the pretracheal and retrotracheal mediastinum contacting the anterior wall of the trachea, the medial wall of the superior vena cava, and most of the posterior wall of the trachea in the majority of patients. The presence of an azygos lobe significantly alters the contour of the right mediastinum and changes the relation of lung to the superior vena cava and trachea.

Persistent gallbladder opacification after iopanoic acid cholecystography: diagnostic implications for acalculous cholecystitis.

Recent reports in the surgical literature state that persistent dense visualization of an otherwise normal-appearing gallbladder 36 hr after the administration of iopanoic acid is highly suggestive of acalculous cholecystitis. To determine the incidence and significance of persistent gallbladder visualization, 324 patients and 66 asymptomatic controls were evaluated. An equal percentage (about 10%) of both groups showed persistent dense gallbladder opacification 36 hr after iopanoic acid ingestion. The results do not support the contention that patients with acalculous cholecystitis can be identified by simply obtaining an additional abdominal radiograph the day after oral cholecystography.