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.

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.

Color Doppler Energy(CDE): Initial Ten-Months Experience

PURPOSE: Color Doppler Imaging(CDI) has shortcomings, including random noise, aliasing, and angle dependence. To overcome these, a method using CD US, termed power doppler or Color Doppler Energy(CDE), has recently been introduced. The purpose of this study was to show the clinical usefulness of CDE. MATERIALS AND METHODS: We retrospectively analyzed the CDI and CDE of 61 cases(20 renal pseudotumors, 8 musculoskeletal inflammations, 17epididymitis or epididymo-orchitis, 3 vaicoceles, 1 normal testis, 1 hepatocellualar carcinoma, 7 renal cell carcinomas, 1 renal angiomyolipoma, and 3 splenic varices). CDI and CDE scans were obtained at the same region with constant scan plane. The color gain was increased until noise first became perceptible, and scans were always obtained in such a way that the maximum amount af vascularity was shown. There after, the vascularity, vascular displacement, and the vascular relationship between CDI and CDE were compared. RESULT: In 17 of 20 cases of pseudotumor in the kidney, normal vascularity was identified in CDI and CDE, but was more clearly visible in CDE. In three cases, there was no visible vascularity in CDI, but normal vascularity in CDE. In eight cases of musculoskeletal inflammation and 17 cases of epididymitis with or without or chitis, the vascularity was increased due to hyperemia, which was more prominently seen in CDE than in CDI. In three varicoceles, CDE appeared to bebetter in demonstration low velocity flow. In one patient who was suspected of having acute testicular torsion, CDE was helpful in excluding this suspicion. In one case of hepatocellular carcinoma, seven cases of renal cell carcinoma, one case of renal angiomyolipoma, and three cases of splenic varices, CDE was better than CDI in showing the vascularity, vascular relationship, and vascular displacement. CONCLUSION: CDE is a potential lyuseful adjunct to standard CDI.

Role of 3-D CT Reconstruction of Laryngeal IVlucosal Surface in Preoperative Staging of Laryngeal Cancer

PURPOSE: CT or MRT is performed in preoperative staging of laryngeal cancer. These methods are used in assessment of the deep tissues and cartilage of the larynx, but cannot compete with laryngoscopy in the evaluation of the laryngeal surface. The purpose of this study is to evaluate feasibilty and clinical value of the 3-D reconstruction of the mucosal surface in laryngeal cancer. METHODS AND MATERIALS: Twenty two patients with laryngeal cancer proved by means of surgical.exploration (pathologic) or clinical examinations including laryngoscope, imaging studies and biopsy underwent preoperative staging with computed tomography(G-P);and three dimensional(3D) CT reconstruction. The TNM classification of the American Joint Committee on Cancer was used to compare the imaging findings with pathologic or clinical staging. RESULTS: When the extension of primary tumor(T staging) was evaluated, the findings at only transaxial CT and those at pathologic or clinical examination were concordant in 8 of 14 cases(57.1%) of supraglottic tumor, and 3 of 6 cases(50%) of glottic tumor. The overall accuracy of CT with additional 3D-reconstruction was 85.7% for assessment of supraglottic tumor, and 66.6% for glottic tumor. CONCLUSION: 3D CT reconstruction after transaxial CT may improve outcome in preoperative staging of laryngeal cancer and has a potential value in guiding management decisions.

CT Findings of Abdominal Tuberculosis

PURPOSE: To evaluate the CT features of abdominal tuberculosis by the pattern anaylsis. MATERIALS AND METHODS: We retrosepctively reviewed the CT findings of confirmed abdominal tuberculosis in 16 patients. Of the 16 patients, 1 was man and the remaining 15 were women with an average age of 34.1 years and the highest incidence in the twenties of age. Intravenous and oral contrast agents were used in all patients. The amount and location of ascites and the changes in the omenturn, mesentery, bowel wall, and peritoneum were analyzed. The morphologic feature, size and main compartment of involvement were also evaluated in the cases with lymphadenopathy as well as other changes in intraabdominal organs. RESULTS: The abdominal tuberculosis was more common in the female(15/16, 93.8%) and could be classified into 3 patterns on their CT findings;Complex ascitic, lymphadenopathy, or abscess forms. The complex ascitic form(10/16, 62.5%) was most commonly seen and characterized by uneven distribution and Ioculation of intraperitoneal fluid collection and marked changes of the omenturn and mesentery. The lymphadenopathy form(3/16, 18.8%) was characterized by central low density and peripheral rim enhancement on postcontrast CT with common involvements of porta hepatis and upper abdominal and paraaortic lymph nodes. The abscess form(3/16, 18.8%) was mainly related to the pelvic abscesses. CONCLUSION: CT was valuable in analyzing the patterns of the lesions and making a diagnosis of abdominal tuberculosis.

Dynamic Study of the Larynx with Spiral CT

PURPOSE: It is essential to know the functional and morphologic changes of the larynx in the evaluation of laryngeal lesions. Conventional CT which has relatively long examination time is not suitable for this aim. The purposes of this study are to evaluate the capability of spiral CT in the dynamic study of the larynx and to know whether this new technique can replace conventional laryngography or not. MATERIALS AND METHODS: Five healthy volunteers and 20 patients with laryngeal lesions underwent spiral dynamic CT scans with 3-dimensional reconstruction of the mucosal surface. A series of spiral CT scans were done while the volunteers performed various laryngeal positions to obtain the functional and morphologic information. The maneuvers used were:quite breathing, "E" phonation, Valsalva maneuver, modified Valsalva maneuver, and a new method of our own, "modified breath holding" technique. The patients were scanned when in quite breathing. Additioal scans were obtained by using the "modified breath holding" technique. RESULTS: The dynamic study with spiral CT could provide high resolutional images which nicely depicted the mobility of vocal cords and the mucosal changes of the laryngeal cavity in both healthy volunteer and patient groups. In patient group, the new "modified breath holding" technique was easier and more reproducible than other maneuvers. CONCLUSION: Spiral CT allows a dynamic study of the larynx and can be a new alternative of laryngography.

Dynamic Liver Scan with Sprial CT

PURPOSE: Dynamic liver scan with spiral CT during a single breath hold was performed for To determing the optimal timing of scanning and the degree of the enhancement of liver and vessel. MATERIALS AND METHODS: Liver spiral CT was performed on 143 patients and dynamic sequence scan on 2 normal volunteers. After baseline spiral CT without contrast enhancement, spiral CT was performed after administration of a bolus of 100 ml of nonionic contrast material intravenously with mechanical power injector at the constant injection rate of 2 ml/sec. Cephalocaudal scanning was started 45 seconds after the beginning of injection. In the majority of cases we employed 16-24 continuous scanning with table feed of 10 mm, slice thickness of 10 mm, and reconstructed in 5 or 10 mm section increments. We measured degree of enhancement of aorta, IVC, and liver parenchyma in all images. RESULTS: We have achieved bolus phase at all images from the following measured date; 170-250 H. U at aorta, 110-150 H. U at IVC, 80-125 H. U at liver parenchyma, 100-130 H. U at spleen, which shown contrast difference between aorta and IVC at least 45 H. U. At the dynamic sequence scan, aortic and vascular CT atternuation reaches a peak at 55-60sec and peak hepatic enhancement occurred at 70-75 sec with relative plateau achieve at 45 sec. Spiral CT also showed elimination of variation in diaphragmatic excursion. CONCLUSION: We could get the disirable phase imaging at overall examination from the dynamic liver scan around 45-60 seconds after injection of contrast media.

Three-dimensional CT reconstruction of the surface of the sinonasal cavities, pharynx and larynx: Normal anatomy

Simulated three-dimensional (3D) imaging represents reformation of conventional sectional imaging data into a series of images that closely resemble the original studied structure. We tried to make 3D mucosal surface images of the sinonasal cavities, pharynx and larynx, and evaluated the feature of normal anatomy in 28 subjects. In the sinonasal cavities, 3D imaging was capable of demonstrating the inner wall of paranasal sinuses and its openings, and general status status of the nasal cavity. In the nasal cavity. In the nasopharynx, 3D imaging provided an easy concept of sectional images as 3D picture and displayed anatomic subsites and lesions comparable to that in fiberscope. In addition, 3D imaging had advantages in overcoming the technical limitations in fiberscope. In the larynx and hypopharynx, 3D imaging gave a 3D concept of the laryngeal structures and presented additive information not seen in axial iamges thus enabling access to regions beyond the scope of fiberscope. In conclusion, 3D imaging allows an easy conceptualization of transaxial CT images in complex anatomic areas and provides additional in formations undetectable in transaxial CT. We believe that the spaces of the sinonasal cavities, pharynx and larynx would be a new field of application of 3D image.

Three-dimensional CT reconstruction of the surface of the sinonasal cavities, pharynx and larynx: Normal anatomy

Simulated three-dimensional (3D) imaging represents reformation of conventional sectional imaging data into a series of images that closely resemble the original studied structure. We tried to make 3D mucosal surface images of the sinonasal cavities, pharynx and larynx, and evaluated the feature of normal anatomy in 28 subjects. In the sinonasal cavities, 3D imaging was capable of demonstrating the inner wall of paranasal sinuses and its openings, and general status status of the nasal cavity. In the nasal cavity. In the nasopharynx, 3D imaging provided an easy concept of sectional images as 3D picture and displayed anatomic subsites and lesions comparable to that in fiberscope. In addition, 3D imaging had advantages in overcoming the technical limitations in fiberscope. In the larynx and hypopharynx, 3D imaging gave a 3D concept of the laryngeal structures and presented additive information not seen in axial iamges thus enabling access to regions beyond the scope of fiberscope. In conclusion, 3D imaging allows an easy conceptualization of transaxial CT images in complex anatomic areas and provides additional in formations undetectable in transaxial CT. We believe that the spaces of the sinonasal cavities, pharynx and larynx would be a new field of application of 3D image.

An experimental study on recovery of renal function using 99mTc DMSA scintigram after percutaneous nephrostomy in unilateral hydronephrosis

Obstruction on the urinary tract eventually results in damage to the kidneys and loss of function. The questions that concern the clinician are the degree of nephron loss in that kidney and the potential for recovery following the relief of obstruction. 99mTc DMSA accumulates in tubule cells and has been proposed as a marker of the tubular mass. The authors estimated the renal uptake ratio of 99mTc DMSA for the degree of nephron loss corresponding to duration of hydronephrosis following left ureteral ligation in 5 NewZealand white rabbits and the potential for recovery following percutaneous nephrostomy of hydronephrosis in 24 rabbits. While the renal uptake ratio of 99mTc DMSA of the kidney with unilateral hydronephrosis following ureteral ligation reduced dramatically within 24 hour, that of the opposite healthy kidney increased, and the total renal uptake ratio was same as normal functioning kidneys before ureteral ligation. Upon ureteral release, there was no evidence of definite recovery or impairment in the experimental kidneys for 5 days. The authors conclude that a combination of ureteral release and administration of some drugs such as renal vasodilator or diuretics is an appropriate treatment for the recovery of function in unilateral hydronephrosis.

CT findings of orbital pseudotumor

To evaluate characteristic CT findings of orbital pseudotumor and to define differentialpoints from other pathology, the authors retrospectively reviewed CT of 19 patients who were prooen to have orbital pseudotumor by clinical course and, in some cases, biopsy. A variety of CT findings including extraocular muscle thickening(11 cases), streaky infiltration of retroorbital fat(11 cases), mass formation(10 cases), optic nerve thickening (6 cases), conjunctival thickening (5 cases), scleral thickening(4cases), enlarged lacrimal gland(4 cases) and destruction of orbital bone (2 cases) were observed. Thickening of the anterior portion and irregular margin were characteristic findings of extraocular muscle and optic nerve lesions. Mass formation predominantly occurs in the anterior portion of the orbit. In most cases more than two orbital structures are involved by lesion.