DETECTING PULMONARY ABNORMALITIES ON MAGNETIC-RESONANCE IMAGES IN PATIENTS WITH USUAL INTERSTITIAL PNEUMONITIS - EFFECT OF VARYING WINDOW SETTINGS AND GADOPENTETATE DIMEGLUMINE

Rationale and Objectives. We examined the effect of varying window set tings and contrast enhancement on detecting pulmonary abnormalities on magnetic resonance (MR) images in patients with usual interstitial pn eumonitis (UIP). Methods. HRCT scans and MR images from 10 patients wi th UIP were evaluated. T1-weighted MR images were obtained before and after administration of gadopentetate dimeglumine and were photographe d at conventional windows and at windows chosen to increase the conspi cuity of the lung parenchyma (''lung windows''). The four MR image con figurations were mixed with the high-resolution computed tomography (H RCT) scans of these patients and randomized. Corresponding scan levels in each patient were evaluated conjointly by two thoracic radiologist s for the presence of ''honeycomb lung,'' ground-glass opacity, parenc hymal bands, and reticular abnormalities. Lung signal intensity in are as containing ground-glass signal intensity was measured on MR images using regions of interest. Results. The administration of gadopentetat e dimeglumine significantly improved the detection of honeycomb lung o n scans photographed at lung windows, but it did not significantly inf luence the detection of ground-glass abnormalities. The use of lung wi ndows improved the detection of ground-glass abnormalities for both en hanced and unenhanced scans, but lung windows improved the detection o f honeycomb lung only for enhanced scans. All MR image configurations were insensitive compared with HRCT scans for detecting parenchymal ba nds and reticular abnormalities. There was a good correlation between measured lung signal intensity and visual ground-glass profusion score . Conclusion. The visibility of pulmonary abnormalities on MR images o f patients with UIP is limited compared with that of HRCT scans. The i mproved visibility of some parenchymal abnormalities after intravenous administration of gadopentetate dimeglumine and with the use of lung windows is insufficient to warrant their routine use in thoracic MR im aging.