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.

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.

Fixed Vocal Cord in Laryngeal Cancers: Mechanisms and Spiral CT Findings

PURPOSE: To analyze the causes of vocal cord fixation in laryngeal cancer and to demonstrate its spiral CT findings. MATERIALS AND METHODS: We retrospectively applied the five pathologic mechanisms of vocal cord fixationto spiral CT findings and evaluated mechanisms of fixed vocal cord in 16 patients with laryngeal cancer of T3 or more on staging. CT findings of another six patients (T2) showing one or more suspicious mechanisms of vocal cord fixation in conventional CT were compared with those of the 16 patients (T3 or more). RESULTS: In 16 patients with laryngeal cancer of T3 or more, the most common finding of vocal cord fixation was the complete replacement of the true vocal cord (including the thyroarytenoid and vocalis muscle) by the tumor and tumor invasion of the paralaryngeal space (n = 16). Other findings were tumor invasion and fixation of the cricoarytenoid joint (n = 9), interference with cord mobility by the bulky mass (n = 6), tumor invasion of the thyroid cartilage, with vocalcord fixation (n = 4) and subglottic tumor spread (n = 3). In another six patients (T2) with suspicious vocal cordfixation, conventional CT showed partial vocal cord invasion and intact or minimal invasion of the paralaryngeal space (n = 3), a bulky mass without vocal cord invasion (n = 1) and subglottic extension but movable vocal cord (n= 2). CONCLUSION: Although the cause of vocal cord fixation from laryngeal cancer may be due to one of five patterns of cancer spread, or to a combination of these, the most common spiral CT finding is complete replacement of true vocal cord by the cancer and tumor invasion of the paralaryngeal space. Accurate evaluation of vocal cord fixation and the extent of the tumor could be evaluated with spiral CT using the breathing technique.

CT Findings of Silicosis

PURPOSE: To describe chest radiographic and CT findings of silicosis, and to compare their findings. MATERIALS AND METHODS: Ten coal miners and six stonemasons were included in this study. All were male and their mean age was 53.1. The mean duration of dust exposure was 15.2 years(range, 5-30 years) in coal miners and 25.3years(range, 15|35 years) in stonemasons. Chest radiographs(n=16), conventional CT scans(n=4), and high resolutionCT(HRCT) scans(n=13) were evaluated. Parenchymal abnormalities were interpreted on the basis of ILO standardfilms(1980) in chest radiographs and on the basis of CAP(College of American Pathologists, 1979) in CT(HRCT)films. RESULTS: Chest radiographs revealed large opacities(n=8), small opacities(n=6), and normal findings(n=2).Type r(n=4) and category 1/1(n=2) were most common for small opacities, while for large opacities, category B(n=4) and category c(n=4) were most common. These small and large opacities were located predominantly in the area of the upper and middle lung. Associated findings were emphysema(n=7), eggshell nodal calcifications(n=3), pneumothorax(n=3), C-P angle blunting(n=4), and pleural thickening(n=1). CT scans revealed micronodules(n=16), nodules(n=3), and progressive massive fibrosis(PMF, n=8). All these lesions were located in the upper and middlelungs, especially in the central portion of the posterior lung. PMF showed diffuse and homogenous(n=3) andpuntate(n=2) calcifications, cavitations(n=5), air bronchograms(n=3), and necrosis(n=1). Peripheral paracicatricalemphysema was associated with PMF(n=8). Other findings were pneumothorax(n=4), emphysema(n=10), hilar andmediastinal nodal enlargement(n=11), bronchial wall thick-enings(n=6), bronchiectasis(n=1), pleuralthickening(n=7), parenchymal fibrosis(n=1), and pulmonary tuberculosis(n=2). CONCLUSION: Small and large opacities in chest radiographs and micronodules, nodules, and PMFs in CT(HRCT) films were located predominately inthe upper and middle lungs, especially in the central portion of the posterior lung in CT films. CT was superiorto plain chest radiographs in the following ways : (1) in the early detection of small opacities, including subpleural micronodules, and in the precise evaluation of their concentration and topography ; (2) in the detection of cavitation or calcification within conglomerate large opacity lesions ; (3) in the detection of hilarand mediastinal nodal enlargements ; and (4) in quantitative assessment of the severity of emphysema.