Diagnosis of cerebral metastases: double-dose delayed CT vs contrast-enhanced MR imaging.
For patients suspected of having cerebral metastases, double-dose delayed CT (DDD-CT) has proved significantly more sensitive than CT scans obtained immediately after administration of a lesser dose of iodinated contrast material. Previous reports confirm the advantages of postcontrast MR imaging over contrast-enhanced CT, but data comparing DDD-CT and contrast-enhanced MR have not been reported. This study describes comparative imaging results in 23 patients who had contrast-enhanced MR imaging to clarify equivocal findings on DDD-CT studies. Contrast-enhanced MR demonstrated more than 67 definite or typical parenchymal metastases. T2-weighted MR revealed more than 40, while DDD-CT revealed only 37 typical metastatic lesions. Three patients had five or fewer lesions on DDD-CT and lesions "too numerous to count" on MR. The frequency of equivocal or unconvincing lesions was similar on DDD-CT (11) and contrast-enhanced MR (10). On T2-weighted images, we noted a substantially higher number of equivocal lesions (19), fewer definite metastases, and a number of definite metastases that had no corresponding lesion on the enhanced studies, confirming the inability of T2-weighted imaging to specifically identify cerebral metastases. In one case, multiple tiny lesions on T2-weighted images were not apparent on DDD-CT scans and were recognized only in retrospect on contrast-enhanced MR images. In this series, MR with enhancement proved superior to DDD-CT for lesion detection, anatomic localization of lesions, and differentiation of solitary vs multiple lesions. Cost-benefit considerations precluded a comparison between the two techniques in all patients suspected of having cerebral metastases.(ABSTRACT TRUNCATED AT 250 WORDS)
Davis
P C
PC
Department of Radiology, Emory University School of Medicine, Atlanta, GA 30322.
Hudgins
P A
PA
Peterman
S B
SB
Hoffman
J C
JC
D000328:Adult; D000368:Aged; D001932:Brain Neoplasms / Q000175:diagnosis / Q000000981:diagnostic imaging / Q000556:secondary*; D001943:Breast Neoplasms / Q000175:diagnosis / Q000000981:diagnostic imaging; D003287:Contrast Media; D005260:Female; D019786:Gadolinium DTPA; D006801:Humans; D007680:Kidney Neoplasms / Q000175:diagnosis / Q000000981:diagnostic imaging; D008175:Lung Neoplasms / Q000175:diagnosis / Q000000981:diagnostic imaging; D008279:Magnetic Resonance Imaging / Q000379:methods*; D008297:Male; D008545:Melanoma / Q000175:diagnosis / Q000000981:diagnostic imaging / Q000556:secondary; D008875:Middle Aged; D009101:Multiple Myeloma / Q000175:diagnosis / Q000000981:diagnostic imaging; D009382:Neoplasms, Unknown Primary / Q000175:diagnosis / Q000000981:diagnostic imaging; D009942:Organometallic Compounds; D004369:Pentetic Acid; D014057:Tomography, X-Ray Computed / Q000379:methods*
D003287:Contrast Media; D009942:Organometallic Compounds; D004369:Pentetic Acid; D019786:Gadolinium DTPA