Radiology, Vol 196, 445-451, Copyright © 1995 by Radiological Society of North America
Renal masses: assessment of corticomedullary-phase and nephrographic- phase CT scans
RH Cohan, LS Sherman, M Korobkin, JC Bass and IR Francis
Department of Radiology, University of Michigan, Ann Arbor 48109, USA.
PURPOSE: To evaluate the role of thin-section helical computed tomography
(CT) performed during the corticomedullary phase (CMP) and nephrographic
phase (NP) of contrast enhancement in the detection and characterization of
renal masses. MATERIALS AND METHODS: Renal CT scans and medical records of
33 patients were retrospectively reviewed. In all examinations, 5-mm-thick,
contiguous, helical-mode scans were obtained before and 40 seconds after
initiation of dynamic bolus injection of contrast material (CMP images);
5-mm-thick, contiguous, axial-mode scans were obtained after completion of
CMP scanning (NP images). RESULTS: At review of CMP, NP, and combination
images, 259, 389, and 417 lesions, respectively, were identified. The
greatest difference in detection occurred in the renal medulla, with 25
lesions identified on CMP images and 111 lesions identified on NP images.
False- positive results occurred when CMP images were reviewed without NP
images. CONCLUSION: CT scans obtained only during the CMP of contrast
enhancement fail to depict many renal masses that are easily seen on NP
images.
