High-resolution CT in the acute exacerbation of cystic fibrosis: evaluation of acute findings, reversibility of those findings, and clinical correlation.

OBJECTIVE: The aims of this study were threefold: to compare high-resolution CT (HRCT) of adult patients with cystic fibrosis (CF) during acute exacerbations with asymptomatic patients with CF, to evaluate reversibility of HRCT abnormalities after exacerbations, and to correlate HRCT with clinical parameters. SUBJECTS AND METHODS: Nineteen symptomatic and eight asymptomatic patients were prospectively evaluated by HRCT and pulmonary function tests (PFTs). Symptomatic patients were reassessed 2 weeks after the exacerbation. Studies were independently reviewed by two radiologists using a modified Bhalla scoring system, noting the presence, extent, and severity of bronchiectasis, peribronchial thickening, mucus plugging, and atelectasis or consolidation. Modifications to the Bhalla system included evaluation of the presence and profusion of centrilobular nodules and air-fluid levels within bronchiectatic cavities. The highest possible score was 24 points. Higher scores indicated greater severity. Mosaic perfusion was noted but not included in the modified Bhalla HRCT score. Total modified Bhalla HRCT score and components of the HRCT score were correlated with corresponding PFT parameters. RESULTS: Bronchiectasis, peribronchial thickening, mucus plugging, centrilobular nodules, and mosaic perfusion were identified in symptomatic and asymptomatic patients. Air-fluid levels in bronchiectatic cavities, identified in two patients, represented the only finding limited to acute exacerbation. Reversible findings included air-fluid levels (100%), centrilobular nodules (36%), mucus plugging (33%), and peribronchial thickening (11%). Total HRCT severity scores of symptomatic and asymptomatic patients correlated with forced vital capacity (FVC) (r = .44, p = .01) and forced expiratory volume at 1 sec (FEV1) (r = .34, p = .04). Severity of bronchiectasis correlated with FVC (r = .50, p = .004) and FEV1 (r = .40, p = .02). Mucus plugging and centrilobular nodules did not correlate with PFT parameters. In the symptomatic patients, improvement in HRCT score correlated with changes in FEV1/FVC (r = .39, p = .049). CONCLUSION: Air-fluid levels in bronchiectatic cavities were the only parenchymal finding shown by HRCT that was limited to the acute exacerbation of CF in our study population. However, this finding was rare, being seen in two of 19 patients. Mucus plugging, centrilobular nodules, and peribronchial thickening were potentially reversible findings in symptomatic patients. HRCT accurately revealed disease severity in patients with CF. We also found that changes in HRCT scores correlated with clinical improvement as determined by PFTs.

Interpretation of chest radiographs in AIDS patients: usefulness of CD4 lymphocyte counts.

Specific infections and neoplasms that are complications of acquired immunodeficiency syndrome (AIDS) occur within various CD4 lymphocyte count ranges. Knowledge of how these counts correlate with radiographic appearances of these entities can limit the differential diagnosis because certain conditions are uncommon above a specific count. In patients with CD4 lymphocyte counts above 200 cells/mm3 and radiographic findings of cavitary and noncavitary consolidation, bacterial pneumonia and Mycobacterium tuberculosis are the major diagnostic considerations. As the CD4 lymphocyte count falls, these infections are still common; however, cavitation is seen less frequently with Mycobacterium tuberculosis, and unusual bacterial infections, including those caused by Rhodococcus equi and Nocardia asteroides, should be considered. In patients with counts below 200 cells/mm3, Pneumocystis carinii pneumonia is the most common infection, usually manifesting radiographically as a reticular interstitial pattern. At CD4 lymphocyte counts of 50-200 cells/mm3, disseminated fungal infection and Kaposi sarcoma become prevalent. In patients with advanced AIDS and counts below 50 cells/mm3, radiographic nodular or reticular patterns may indicate AIDS-related lymphoma and cytomegalovirus and Mycobacterium avium-intracellulare infections. When CD4 lymphocyte counts are applied to interpretation of chest radiographs in AIDS patients, the working differential diagnosis of a radiographic pattern can be tailored to the clinical situation of a given patient.

Pulmonary complications of cystic fibrosis in adults.

The demographics of cystic fibrosis (CF) are continuously changing, with adults representing a growing percentage of the patient population, which is expected to reach 50% by the year 2000. Pulmonary complications are primarily responsible for the high morbidity and mortality in this disease. Although the radiographic findings are quite specific, the correct diagnosis may not be suggested in the adult patient because of a lack of familiarity with its pulmonary manifestations in this age group. High-resolution CT (HRCT) has contributed to our understanding of the radiographic findings, especially at the level of the small airways. The role of imaging, including chest radiography and HRCT, is discussed. Issues that remain controversial include imaging in the acute pulmonary exacerbation, and the routine use of imaging as part of clinical scoring and in monitoring responses to new treatment modalities.

Pathophysiological basis of lumbar disc degeneration: imaging analysis.

This article provides a brief synopsis of the pathoanatomic basis of disc degeneration. An attempt is made to correlate CT, MR and CT discographic findings. The T2-weighted sagittal images are the most sensitive for evaluating disc degeneration. The contour changes on axial CT and MR scans are sensitive for abnormalities but not always specific. The CT discogram adds information unavailable by other imaging methods pertaining to the internal architecture of the disc. It additionally defines focal nuclear herniations and also is helpful in evaluating the stage of disc degeneration.

Magnetic resonance imaging and two-dimensional echocardiography. Alternative approach to aortography in diagnosis of aortic dissecting aneurysm.

Unrecognized acute dissection of the aorta requires rapid and accurate diagnosis for appropriate management. The "gold standard" for diagnosis has been invasive angiography, but this diagnosis can be achieved noninvasively via two-dimensional echocardiography, computed tomographic scanning, and magnetic resonance imaging. Two patients are described in whom echocardiography and magnetic resonance imaging were complementary diagnostic aids. The advantages and disadvantages of echocardiography, computed tomographic scanning, magnetic resonance imaging, and aortography in aortic dissection are discussed. It is anticipated that a combination of noninvasive diagnostic aids will eliminate the need for invasive angiography in many instances in the future.

Computerized tomography and radionuclide scanning in hepatic disease: a retrospective study.

This was a retrospective study of 117 patients, who had both computerized tomography (CT) and nuclear scans of the liver. In the evaluation of hepatic masses, the nuclear and CT scans, demonstrated 83% and 77% of the masses, respectively, in combination they demonstrated 97%. The nuclear scan proved to be a more sensitive procedure for demonstrating the presence of intrahepatic pathology. The CT scans were better able to demonstrate specific disease entities, such as biliary obstruction and fatty infiltration of the liver. CT was also able to evaluate adjacent organs. When used in combination, CT and nuclear scans tended to complement each other and in many cases were helpful in arriving at a more specific diagnosis.

Preoperative diagnosis of a ruptured intracranial dermoid cyst by computerized tomography. Case report.

A case of ruptured intracranaial dermoid cyst in the right middle fossa is reported. A definitive diagnosis of the lesion and the fact that it had ruptured was made possible by specific computerized tomographic findings. The findings were confirmed at surgery.

Computed tomography in the diagnosis of renal masses.

CT diagnosis of renal lesions proved to be highly efficient and reliable. This modality was most accurate in diagnosing renal cysts and the great majority of solid lesions. There was an indeterminate group (5% of cases studied) that included cysts, tumors and abscesses. This group requires additional investigation, but angiography is often not conclusive because of the avascular nature of these tumors. Other problem areas included cysts with apparently irregular margins and artifacts produced by the presence of contrast agent in the collecting systems.

Diagnosis of isodense subdural hematomas by computed tomography.

Subdural hematomas, whose absorption values approximate those of adjacent brain, are not visualized in routine computed tomography. Two clues indicating the presence of such "isodense" subdural hematomas are: (1) unilateral effacement of cerebral sulci on the convexities, and (2) midline shift or mass effect on the ventricles in the absence of abnormal areas of diminished or increased density in the brain. Nine cases were detected on pre- and postcontrast studies in 2,500 CT scans of the brain over a 10 month period. Delayed CT scanning 4-6 hr after intravenous contrast injection showed enhancement of the subdural hematoma in three of seven cases.