title: Value of subtraction images in the detection of hemorrhagic brain lesions on contrast-enhanced MR images.
abstract: Contrast-enhanced T1-weighted MR images are known to improve the detection and conspicuity of CNS lesions; however, lesion enhancement may be indistinguishable from contiguous hemorrhagic areas of intrinsically increased signal intensity. In a series of cranial MR studies in 22 pediatric oncologic patients with evidence of subacute hemorrhage, we found that subtracting the unenhanced from the enhanced T1-weighted images was essential in 14 of the cases to visualize and/or characterize the enhanced tissue in the presence of adjacent hemorrhage. In six patients, a nodular pattern of enhancement suggestive of tumor was detected and/or outlined only after subtraction. In eight patients, linear benign-appearing enhancing margins were seen clearly only after subtraction. In the remaining eight patients, the presence and shape of enhancement was verified with subtraction. Subtraction is a useful, simple, and rapid postprocessing procedure that does not increase scan time or require modification of standard pulse sequences. Subtraction separates the enhanced areas from adjacent bright hemorrhage.
authors.affiliation: Department of Diagnostic Imaging, St. Jude Children's Research Hospital, Memphis, TN 38101.
authors.forename: S L
authors.initials: SL
authors.lastname: Hanna
authors.forename: J W
authors.initials: JW
authors.lastname: Langston
authors.forename: S A
authors.initials: SA
authors.lastname: Gronemeyer
mesh_terms: D000293:Adolescent; D001927:Brain Diseases / Q000175:diagnosis; D001932:Brain Neoplasms / Q000175:diagnosis / Q000556:secondary; D002543:Cerebral Hemorrhage / Q000175:diagnosis*; D002648:Child; D002675:Child, Preschool; D003287:Contrast Media; D003937:Diagnosis, Differential; D005069:Evaluation Studies as Topic; D005260:Female; D005909:Glioblastoma / Q000175:diagnosis; D006801:Humans; D007089:Image Enhancement; D007223:Infant; D008279:Magnetic Resonance Imaging; D008297:Male; D010272:Parasitic Diseases / Q000175:diagnosis; D011184:Postoperative Period; D013382:Subtraction Technique / Q000592:standards*
chemical_list: D003287:Contrast Media