Kazuhiro Shimamoto

Preoperative staging of thyroid papillary carcinoma with ultrasonography

OBJECTIVE To evaluate the usefulness of ultrasonography including Doppler flow imaging for the preoperative staging of thyroid papillary carcinoma. MATERIALS AND METHODS In 77 patients with thyroid papillary carcinoma who underwent total thyroidectomy, the accuracy of ultrasonography in preoperative clinical staging was assessed with use of pathologic examination on the basis of TNM classification by the International Union Against Cancer (UICC). RESULTS In 63 (81.8%) cases, T categories were estimated accurately. The sensitivity in depicting tumor extension into the prethyroidal muscle and/or the sternocleidomastoid muscle was 77.8%, whereas the sensitivity for invasion into the trachea and the esophagus was 42.9 and 28.6%, respectively. In 37 (48.1%) cases, N categories were underestimated, and the sensitivity in the detection of regional lymph node metastasis was 36.7%. Doppler flow imaging was performed in 36 patients, and no correlation was found between flow patterns and the presence of local invasion or regional lymph node metastasis. CONCLUSION Ultrasonography was useful for preoperative investigation of thyroid papillary carcinoma, but several limitations existed, especially in evaluating extracapsular invasion to deep locations and regional lymph node metastasis.

CT findings in groove pancreatitis: correlation with histopathological findings

Objective To clarify the CT characteristics of groove pancreatitis, which is a segmental form of chronic pancreatitis. Materials and Methods The CT findings in four patients with proved groove pancreatitis were reviewed retrospectively. The examinations consisted of plain CT, dynamic CT, and high dose enhancement CT in each patient. Correlation between the CT findings and the resected specimens was performed in three patients. Results In every patient a mass was detected in the head of the pancreas that involved the duodenum. Dynamic CT demonstrated a poorly enhancing lesion extending between the pancreatic head and the duodenum. Cysts in the duodenal wall and/or the groove and duodenal stenosis due to wall thickening were seen in four and three patients, respectively. These CT findings reflect the histological characteristics of this disease. Conclusion Computed tomography, including dynamic study, can demonstrate the characteristic findings of groove pancreatitis and suggest the diagnosis.

Thyroid nodules : evaluation with color Doppler ultrasonography

Forty‐seven patients with thyroid nodules (13 papillary carcinomas, 14 adenomas, and 20 adenomatous goiters) underwent color Doppler sonography with a 7.5 MHz transducer. Perinodular or intranodular color flow signals were depicted in 10 of 13 papillary carcinomas, in 10 of 14 follicular adenomas, and in 14 of 20 adenomatous goiters. No correlation existed between the presence of color signals and pathology, whereas the detection rate of color signals had a dependence on the size of the lesions. No specific flow pattern for malignancy could be found. Color Doppler sonography would not improve the ability to differentiate benign from malignant nodules significantly.

Role of ultrasonography in the detection of intraductal spread of breast cancer: correlation with pathologic findings, mammography and MR imaging

Abstract. The purpose of this study was to assess the role of US in the detection of intraductal spread of breast cancer in comparison with mammography (MMG) and MRI. In 46 patients with breast cancer, US features of the intraductal component were classified as ductal type or distorted type. Histopathologically, 29 of 46 (63 %) cases had intraductal components, and the sensitivity, specificity, and accuracy rates in detection of intraductal spread were 89, 76, and 85 %, respectively. Each US pattern demonstrated good correspondence to the histologic components, and the distorted type correlated well with comedo-type carcinoma. Mammography was performed in all cases, and the sensitivity, specificity, and accuracy rates in detection of intraductal spread were 55, 100, and 72 %, respectively. In comedo type, MMG could diagnose the extent of intraductal spread more accurately compared with US examination. Magnetic resonance imaging comparison was available in 25 cases. Magnetic resonance imaging depicted intraductal extension as an enhanced area during the early phase of a contrast enhancement study with a sensitivity of 93 %. Ultrasound and MRI were closely related in terms of morphologic characteristics: the ductal type of US image correlated well with linear enhancement on MRI, whereas the distorted type correlated with regional or segmental enhancement. Current US examination is useful in depicting the intraductal spread of breast cancer; however, US has a tendency to underestimate intraductal component of comedo type compared with MMG and MRI.

Budd-Chiari Syndrome with Long Segmental Inferior Vena Cava Obstruction: Treatment with Thrombolysis, Angioplasty, and Intravascular Stents

The authors describe a patient with Budd-Chiari syndrome caused by long segmental thrombotic obstruction of the inferior vena cava associated with paroxysmal nocturnal hemoglobinuria. The patient was successfully treated with a combination of local thrombolytic therapy, balloon angioplasty, and placement of Gianturco expandable metallic stents.

Predictive Value for Malignancy of Suspicious Breast Masses of BI-RADS Categories 4 and 5 Using Ultrasound Elastography and MR Diffusion-Weighted Imaging

OBJECTIVE The aim of this study is to evaluate the ability of ultrasound elastography and MR diffusion-weighted imaging (DWI) to predict malignancy of breast masses, with subsequent recommendation for biopsy. MATERIALS AND METHODS For 115 breast masses classified as BI-RADS category 4 or 5, which were assessed according to combined findings of mammography, B-mode sonography, and dynamic contrast-enhanced MRI, two radiologists retrospectively evaluated the elasticity scores using ultrasound elastography and the apparent diffusion coefficient (ADC) values using MR DWI. The diagnostic abilities of these two techniques were analyzed by using univariate and multivariate logistic regression analysis. RESULTS In the analysis of all 115 breast masses, the elasticity score was predictive of malignancy, whereas the ADC value was not independently predictive. In an analysis of the 52 masses assessed as BI-RADS category 4, the elasticity score was found to be a significant predictor of malignancy, compared with the ADC value, which was a nonsignificant predictor. In an analysis of the 63 masses assessed as BI-RADS category 5, neither the elasticity score nor the ADC value was a significant predictor of malignancy. CONCLUSION Our results show that elasticity imaging provides relatively reliable predictions for malignancy, especially in BI-RADS category 4 masses, compared with MR DWI.

The influence of liquid crystal display (LCD) monitors on observer performance for the detection of nodular lesions on chest radiographs

PurposeTo access the influence of liquid crystal display (LCD) monitors on the detectability of nodular lesions depicted on chest radiographs by comparing them with a high-resolution cathode ray tube (CRT) monitor.Material and methodsTen radiologists interpreted 247 soft-copy images on LCD monitors with pixel arrays of 1,024×1,280, 1,200×1,600, 1,536×2,048 and 2,048×2,560, and a CRT monitor with a pixel array of 2,048×2,560, and were asked to indicate their individual confidence levels regarding the presence of a nodule. These images were chest radiographs with and without a lung nodule from the “Standard Digital Image Database” created by the Japanese Society of Radiological Technology. The luminance distributions of all monitors were adjusted to the same, and the ambient illumination was 200 lux. Observer performance was analyzed in terms of the receiver-operating characteristics.ResultsNo significant statistical differences in nodule detection performance were found among the four LCD monitors and the CRT monitor.ConclusionThe nodule detection performance on the LCD monitors with a spatial resolution higher than a matrix size of 1,024×1,280 was found to be equivalent to that on the high-resolution CRT monitor.

Influence of CRT workstation on observer's performance

The effects of the operability of the prototype CRT workstation and room illumination upon observers performance were studied. In the experiment of reading CT images as a routine daily work at the CRT workstation, the average time required to analyse one CT image under a room illuminance of 100 lux was longer than that on the film viewbox. Prolongation occurred due mainly to the longer time required to retrieve and to arrange images as observers desired, and the limitation to the number of images simultaneously displayed on two CRT monitors. In the ROC studies to detect small pulmonary nodules on CRT images of computed radiography with imaging plate, illuminance around 170 lux showed the best result and a statistically significant difference (P less than 0.05) as compared with that of 480 lux. In addition to the radiologists visual performance, room illumination must also be taken into consideration as it influences the observers performance and diagnostic efficiency.

Limited efficacy of (18)F-FDG PET/CT for differentiation between metastasis-free pancreatic cancer and mass-forming pancreatitis.

Objective Differentiation between metastasis-free pancreatic cancer and mass-forming pancreatitis is important to avoid unnecessary operative procedures. This study was aimed at evaluating the efficacy of PET/CT with 18F-FDG (FDG PET/CT) for the differential diagnosis between them. Patients and Methods FDG-PET/CT was performed in 47 study patients with pancreatic masses and without any detectable metastases, 33 of which cases were finally diagnosed as pancreatic cancer and the other 14 as pancreatitis, and the corresponding imaging data were evaluated retrospectively. The maximal SUV (SUVmax) within the masses were determined at 1 hour and mostly at 2 hours after intravenous injection of FDG. Results SUVmax at 1 hour in pancreatic cancer was significantly higher than that in mass-forming pancreatitis, and the change in SUVmax from 1- to 2-hour time points was more consistent with pancreatic cancer than with mass-forming pancreatitis. However, there remained considerable overlapping between the SUVmax values of both diseases except either at the higher range for pancreatic cancer (> 7.7 at 1 hour or > 9.98 at 2 hours) or at the lower range for mass-forming pancreatitis (<3.37 at 1 hour or <3.53 at 2 hours). No obvious difference was found in the FDG uptake patterns of the mass areas between both diseases. Conclusions Differentiation between metastasis-free pancreatic cancer and mass-forming pancreatitis is difficult by FDG-PET/CT due to considerable overlapping between the SUVmax values of the two diseases, although the differential diagnosis may be possible either at the higher range of SUVmax (> 7.7 at 1 hour or > 9.98 at 2 hours) for pancreatic cancer or at the lower range of SUVmax (<3.37 at 1 hour or <3.53 at 2 hours) for mass-forming pancreatitis.

Influence of monitor luminance change on observer performance for detection of abnormalities depicted on chest radiographs.

Ikeda M, Ishigaki T, Shimamoto K, et al. Influence of monitor luminance change on observer performance for detection of abnormalities depicted on chest radiographs. Invest Radiol 2003;38:57–63. Rationale and Objectives.To investigate how changes in luminance affect the detection accuracy of radiologists viewing chest radiograph images on high-resolution CRT monitors. Materials and Methods.Thirteen radiologists performed a detection task for 11 chest radiograph images with simulated nodules on a monitor with 11 luminance conditions (the maximum luminance ranges from 157.4–369.0 candela/m2) simulating CRT degraded by long-term usage, under the ambient illumination of 200 lux; the observation order was always from the darkest to the brightest. Results.There was a statistically reliable effect of the 11 monitor display conditions on the detection of nodules (P < 0.001). In the conditions in which the maximum luminance of the CRT was 60.7% or below that of the standard display luminance, the correctly detected nodule number reliably deteriorated. Conclusions.The luminance change in CRT monitor display under long-term usage will have a detrimental effect on nodule detection performance in chest radiograph images.