INVERSION-RECOVERY ECHO-PLANAR MR IN ADULT BRAIN NEOPLASIA

PURPOSE: A T1-weighted multishot inversion-recovery (IR) echo-planar M R imaging (EPI) sequence was developed to improve intracranial tissue differentiation; its diagnostic utility was compared with that of conv entional axial T1-weighted spin-echo and axial T2-weighted turbo spin- echo sequences, METHODS: Eighteen patients with known or suspected pri mary or metastatic brain neoplasia were imaged in a 1.5-T unit with IR -EPI sequences, Three observers measured gray/white matter contrast-to -noise ratios and subjectively compared IR-EPI sequences with T1-weigh ted spin-echo and T2-weighted turbo spin-echo sequences for gray/white matter discrimination, visibility of intracranial and vascular struct ures, overall lesion conspicuity, size of lesion(s), and presence and severity of artifacts, RESULTS: Twenty-four lesions (including neoplas ia, infarction, treatment-associated encephalomalacia, nonneoplastic w hite matter signal abnormalities, and basilar artery dolichoectasia) w ere detected in 12 patients,]Basilar artery dolichoectasia was not inc luded in subsequent statistical analysis, Pulsatile flow artifacts wer e markedly reduced on IR-EPI sequences relative to those on T1-weighte d spin-echo sequences, Gray!white matter contrast was greater on IR-EP I images than on T1-weighted spin echo images, Periaqueductal gray mat ter, basal ganglia, optic tracts, cranial nerve V, and claustrum were seen better or as well on IR-EPI images as compared with T1-weighted s pin-echo images, IR-EPI was more sensitive to magnetic sensitivity eff ects, with resultant decreased visibility of cranial nerves VII and VI II and the orbital portion of the optic nerves, For noncontrast sequen ces, lesion conspicuity was better on IR-EPI images than on T1-weighte d spin-echo images in 16 (70%) of 23 lesions and was equal on the two sequences in seven (30%) of 23 lesions, Lesion size, including surroun ding edema, was greater on IR-EPI images than on T2-weighted turbo spi n-echo images in two (9%) of 23 cases and equal in 21 (91%) of 23 case s, Hyperintense foci of methemoglobin were more conspicuous on T1-weig hted spin-echo images, CONCLUSION: Multishot IR-EPI is superior to con ventional T1-weighted spin-echo imaging for parenchymal tissue contras t and lesion conspicuity, and is equal to T2-weighted turbo spin-echo imaging in sensitivity to pathologic entities.