CISS MR Imaging Findings of Epidermoid Tumor: Comparison with Spin-Echo Images

PURPOSE: To evaluate CISS MR imaging findings of epidermoid tumor in comparison with conventional spin-echoimages. MATERIALS AND METHODS: We studied 6 cases of epidermoid tumor in the subarachnoid space. We used a 1.5TMR unit to obtain CISS images(TR/TE/FA ; 12.3msec/5.9 msec/700) and T1- and T2-weighted spin-echo images. CISS MRimaging findings were evaluated with respect to tumor's signal intensity, contour, and relation with adjacentstructures. Conspicuity of the tumor was compared between CISS and spin-echo images. A quantitative analysis wasperformed by measuring tumor to CSF contrast. In qualitative analysis, three radiologists independently comparedCISS image and conventional spin-echo images for visibility of the tumor and graded them into three categories(poor, good, and excellent). RESULTS: Epidermoid tumors were located in the cerebellopontine angle in 4 cases, theprepontine cisstern in 1 case, and the cerebellopontine angle-prepontine cistern in 1 case. The tumors werehyperintense relative to brain parenchyma and hypointense relative to CSF on CISS images, were lobulated, encasedadjacent cranial nerve and vessels, and invaginated into brain parenchyma. In qualitative analysis, CISS imagesshowed clear demarcation between tumor and CSF, exact tumor extension, and tumor's relation with cranial nervesand vessels better than conventional spin-echo images. In quantitative analysis, the mean contrast values of tumorto CSF on T1-, T2-weighted images, and CISS images were 0.12, 0.06, and 0.52, respectively. The contrast value forCISS images was significantly higher than that for T1- and T2-weighted images (P<0.05) . CONCLUSIONS: Epidermoid tumors in the subarachnoid space are better demonstrated on CISS images than on conventional spin-echoimages. This special MR sequence can be added as a routine protocol in the diagnosis of subarachnoid epidermoidtumor.

Usefulness of CISS Technique in the MR Imaging Diagnosis of Intraocular Lesions

PURPOSE: To assess the usefulness of CISS images in the diagnosis of intraocular lesions, we compared CISSimages with 3mm and 1mm sliced spin-echo T2-weighted images. MATERIALS AND METHODS: In 14 patients with 15intraocular lesions(retinal detachment 10, choroidal melanoma, 2 ; cavernous hemangioma, 1 ; PHPV, 1 ; andretinoblastoma, 1). we used a 1.5T MR unit obtain CISS images and 3mm and 1mm sliced spin-echo T2-weighted images.All lesions were analyzed, and after dividing them into two subgroups(linear lesions, n=11 ; mass lesions, n=4),CISS and spin-echo T2-weighted images were compared for detection rate and conspicuity. RESULTS: With regard tothese two parameters, CISS images were superior to 1mm and 3mm sliced spin-echo T2-weighted images. For theassessment of linear lesions, CISS images (detection rate, 100% ; conspicuity, 2.88) were superior to both 1mm and3mm sliced spin-echo T2-weighted images. For mass lesions CISS images were superior to 3mm sliced spin-echoT2-weighted images, but for conspicuity, there was no significant difference between CISS images (2.75) and 1mmsliced spin-echo T2-weighted images(2.2). CONCLUSION: Due to their higher detection rate and greater conspicuity,CISS images were superior to spin-echo T2-weighted images for the diagnosis of intraocular lesions less than 3mmin diameter ; for the diagnosis of intraocular lesions, they might therefore be a useful adjunct to SE images.

Role of EPI in Diagnosing Cavernous Hemangioma & Small HCC: Comparision with Fast T2-Weighted MR Imaging

PURPOSE: To compare single-shot echo-planar MR imaging(EPI) with breath-hold fast T2-weighted imaging(HASTEor Turbo spin-echo T2WI) for evaluation of the role of EPI in distinguishing small hepatocellular carcinoma fromcavernous hemangioma. MATERIALS AND METHODS: We retrospectively evaluated MR images of 35 patients (21 cases ofsmall HCC and 14 cases of cavernous hemangioma). EPI and breath-hold fast T2WI images were obtained and comparedon the basis of lesion detection sensitivity, lesion-to-liver signal intensity ratio(SIR), contrast ratio(CT), andlesion-to-liver contrast to noise ratio(CNR). RESULTS: For the detection of small HCC, the sensitivity of EPI andbreath-hold fast T2WI were equal in 14 of 21 cases(71.4%). The detection sensitivity of cavernous hemangioma withEPI and breath-hold fast T2WI was 100%(14/14). Mean SIR on breath-hold fast T2WI was 2.02+/-0.45 for small HCC and3.65+/-0.97 for cavernous hemangioma; on EPI, the corresponding figures wer 2.91+/-0.57 and 6.98+/-1.37. Mean CR onbreath-hold fast T2WI was 1.16+/-0.58 for small HCC and 2.65+/-0.57 for cavernous hemangioma; On EPI, the figuresobtained were 2.27+/-0.52 and 6.26+/-2.19, respectively. Mean CNR on breath-hold fast T2WI was 14.24+/- 4.098 forsmall HCC and 50.28+/-10.96 for cavernous hemangioma, while on EPI, the corresponding figures were 13.84+/-3.02 and45.44+/-11.21. CONCLUSION: In detecting focal hepatic mass, the sensitivity of EPI and breath-hold fast T2WI arecomparable; for the diagnosis of small HCC and cavernous hemangioma, EPI can provide additional information.