Lumbar MR Myelography with Constructive Interference in Steady State(CISS)-3DFT

PURPOSE: To evaluate the usefulness of 3DFT CISS MR myelography (MRM) by comparing it with 3DFT FISP MRM. MATERIALS AND METHODS: Thirty-four subjects consisting of normal volunteers and patients complaining of back pain underwent lumbar spine MRI, 3DFT CISS MRM, and 3DFT FISP MRM. The 3DFT FISP MRM and 3DFT CISS MRM images were analysed and in each case, the following were compared : sharpness of the dural sac; differentiation of nerve roots and CSF ; visualization of the nerve root sleeve and of dural sac compression. RESULTS: Image acquisition time of 3DFT CISS MRM was shorter than that of 3DFT FISP MRM, and the former was significantly superior to the latter in sharpness of the dural sac (86%, p=0.004), differentiation of nerve roots and CSF (74%, p=0.0168), andvisualization of dural sac compression (90%, p=0.0016). With regard to visualization of nerve root sleeves, 3DFT CISS MRM was superior to 3DFT FISP MRM, but not significantly (68%, p=0.0872). CONCLUSION: 3DFT CISS MRM requiresa shorter image acquisition time and gives a better image than 3DFT FISP MRM; we therefore consider it to be a useful MR method.

CT Grading of Laryngeal Cancer According to the Degree of its Extension: Emphasis on T2 and T3 Tumors

PURPOSE: To analyze the degree of tumor extension in T2 and T3 laryngeal cancer, independently of vocal cord fixation, and to introduce a new CT grading system for use in preoperative T-stage assessment. MATERIALS AND METHODS: Retrospective analysis of degree of tumor extension was performed in 36 patients with laryngeal cancer (T2 glottic, 4 ; T2 supraglottic, 12 ; T3 glottic, 12 ; and T3 supraglottic, 8). T-stage was determined according to clinical and pathologic findings, and based on the TNM classification of AJCC (1992). The degree of tumor extension seen on CT was determined by the number of involved anatomic subsites and compared with T-stage and lymph node metastasis. On the basis of statistical analysis(Fisher's exact test) of those results, we suggest new CT grading system for laryngeal cancer. RESULTS: Fifteen of 20 supraglottic cancer patients showed six or less involved anatomic subsites ; twelve of these 15 (80%) were at stage T2 and three (20%) were T3. Four of the 15 showed lymph node metastasis. The five patients whose number of involved anatomic subsites was seven or more were all T3 ; four (80%) of these showed lymph node metastasis. The difference in the number of involved anatomic subsites in T2 and T3 tumor was statistically significantly different (p<0.05) ; the incidence of LN metastasis was more prevalent in the group with seven or more involved subsites. In glottic cancer, however, no statistically significant difference was observed between T2 and T3 tumors in the number of involved subsites. CONCLUSION: In supraglottic cancer, T1 and T4 stages are determined by degree of tumor extension, irrespective of vocal cord mobility ; T2 and T3 stages are suggested by the number of involved anatomic subsites, without reference to vocal cord mobility. A new CT grading system may thus be made, based on degree of tumor extension. In glottic cancer, however, laryngoscopy or dynamic study with spiral CT are needed for T-stage assessment.