Search

Background Thymoma exhibits a range of histological and biological features and their imaging findings varies. Purpose To evaluate the associations between CT findings of thymomas and their classification according to the Masaoka staging system and World Health Organization (WHO) classification. Material and Methods Eighty-four patients with thymoma were evaluated. Comparisons between the CT findings of Masaoka stage I/II and III/IV lesions, and the WHO type A-B1 (low risk) and B2/B3 (high risk) lesions were performed. Results Stage III/IV thymomas (mean size, 60 mm) were significantly larger than stage I/II (45 mm) lesions and had more irregular shape and contour. Necrosis and calcification were observed in 16 (59%) and nine (33%) stage III/IV thymomas, and 16 (28%) and seven (12%) stage I/II lesions, respectively. Regarding the WHO classification, the high-risk thymomas displayed irregular shape and contour more often than low-risk lesions. There were significant differences between the patterns of mediastinal invasion seen in high- and low-risk groups; 21 (68%) vs. six (12%) lesions demonstrated mediastinal fat invasion, seven (23%) vs. two (4%) lesions exhibited great vessel invasion, five (16%) vs. 0 (0%) lesions displayed pericardial invasion, and 18 (58%) vs. 10 (20%) lesions invaded the lungs, respectively. Conclusion Masaoka stage III/IV thymomas were larger in size, had more irregular shape and contour, and exhibited necrosis and calcification more often than the stage I/II lesions. In the WHO classification, high-risk thymomas demonstrated more irregular shape and contour than low-risk thymomas.

Background Preoperative transcatheter arterial embolization for hypervascular bone and soft tissue tumors plays an important role in reducing intraoperative blood loss (IBL). Purpose To evaluate the use of a gelatin sponge in preoperative transcatheter arterial embolization for hypervascular bone and soft tissue tumors in the pelvis or extremities. Material and Methods Thirty-seven patients (21 men, 16 women; median age, 61 years; age range, 23–79 years) underwent preoperative transcatheter arterial embolization between April 2004 and January 2015. Medical records and images were reviewed, and the technical success rate, clinical success rate, and complications were evaluated. Technical success was defined as a devascularization rate of 75% or higher, and clinical success was defined as intraoperative blood loss (IBL) Results Tumor sizes were in the range of 2.0–13.0 cm (median, 5.0 cm). The devascularization rate was decreased by >75% at follow-up angiography in all cases, and the technical success rate was 100 % (37/37). The median IBL was 491 mL (range, 30–3800 mL), and the clinical success rate was 89% (33/37). The minor complication of local pain was observed in 13 out of 37 cases (35%) during or after embolization, but was controllable by an analgesic. Conclusion Preoperative transarterial embolization using a gelatin sponge appears to be feasible and safe, and may contribute to decreasing IBL.

Background Transcatheter arterial chemoembolization (TACE) has been widely performed for inoperable hepatocellular carcinoma (HCC). Super-selective TACE is preferable to non-selective therapy and it is important to advance the catheter tip as close to the tumor as possible in the feeding artery. A new microcatheter with a 1.9-Fr non-tapered tip has recently become available and this new microcatheter can be inserted into a 2.7-Fr. microcatheter. It is called the triple co-axial (triaxial) system. Purpose To evaluate the clinical usefulness of super-selective TACE for HCC using the triaxial system. Material and Methods We evaluated 63 HCCs that underwent super-selective TACE. Requirements for inclusion in this study were: (a) HCCs 3 cm or less in diameter; (b) TACE performed by a single operator; and (c) no additional treatment in the absence of local progression. All patients were followed for more than 1 year after TACE. The median follow-up period for surviving patients was 20 months (range, 17–31 months). The conventional system was used in 35 HCCs (control group), and the triaxial system was used in 28 (triaxial group). We reviewed angiographies at TACE and follow-up CT, and then evaluated local tumor status in the two groups. Results Local tumor control rates at 3, 6, and 18 months were 64%, 36%, and 29%, respectively, in the triaxial group, and 40%, 14%, and 8.6%, respectively, in the control group ( P = 0.0086). There were no major complications in either group. Conclusion The triaxial system appears to be useful for super-selective TACE and may contribute to achieving higher local control rates for HCC.

Background: The accuracy of 18F-2-deoxy-fluoro-D-glucose positron emission tomography (FDG-PET) for diagnosing nodal status in patients with lung cancer was initially reported as excellent, but, with increasing experience, the problem of false-positive and false-negative assessments has been observed. Purpose: To evaluate the accuracy of FDG-PET for diagnosing nodal status in lung cancer patients with pathologically proven N2 lymph nodes and compare it with that of computed tomography (CT). Material and Methods: Nineteen pN2 patients (13 males and six females) with primary lung cancer undergoing preoperative CT and FDG-PET were investigated. Lymph nodes were considered to be positive when uptake higher than the surrounding mediastinal level was visually observed. Slight symmetrical mediastinal uptake was considered to be negative, representing benign physiological accumulation. Radiological and pathological correlation was investigated, and the association between FDG accumulation and the size of metastatic lymph nodes and metastatic lesions was evaluated. Results: Of the 19 patients, nodal stage determined by using FDG-PET was cN0 in four (21%) cases, cN1 in three (16%), cN2 in nine (47%), and cN3 in three (16%). On CT, nodal stage was cN0 in three (16%) cases, cN1 in seven (37%), cN2 in eight (42%), and cN3 in one (5%). Thus, FDG-PET provided correct N-staging in 47%, under-staging in 37%, and overstaging in 16%. CT staging was correct in 42%, underestimated in 53%, and overestimated in 5%. The maximum area of metastatic foci was 15.8 ±21.3 mm2 (mean ± SD) in false-negative nodes and 75.0±56.3 mm2 in true-positive nodes ( P Conclusion: Diagnostic accuracy of FDG-PET (47%) was low and similar to that of CT (42%). The possibility of false-negative as well as false-positive findings should be recognized in interpreting PET images. Micrometastasis appeared to be the greatest cause of false-negative findings.