Thoracic cage extent of melorheostosis depicted by multislice CT.

The ribs and vertebrae are rarely affected by melorheostosis. We present a case of melorheostosis of the ribs and thoracic vertebrae, in which multislice computed tomography (CT) was useful in depicting its extent and defining its sclerotome distribution.

[Multislice CT of the thorax: effects of contrast material pushed with saline solution using a dual power injector on contrast material dose and perivenous artifacts].

A new method of power injection of contrast material flushed with saline solution for thoracic multislice CT using a dual power injector was evaluated in 105 patients. The patients were categorized into 3 groups of 35 patients each, according to the protocol of contrast material administration: (1) 100 mL of non-ionic contrast material(300 mgI/mL), (2) 75 mL of the same contrast material, and (3) 75 mL of the same contrast material flushed with 30 mL of saline solution. Scanning was performed in a caudal-to-cranial direction. Mean attenuation for the three protocols was measured in the superior vena cava, pulmonary trunk, ascending aorta, and descending aorta. Vascular opacification and perivenous artifacts were graded using four-point scoring by a consensus panel of three blinded radiologists. Intravenous injection of 75 mL of contrast material flushed with saline solution provided significantly better vascular opacification in the superior vena cava(p < 0.001) and pulmonary trunk(p < 0.02) than that provided by a 75 mL or 100 mL injection of contrast material alone. A similar degree of enhancement was observed in the ascending and descending aorta. Further, perivenous artifacts in the subclavian vein were significantly reduced (p < 0.05).

Islet cell tumor of the pancreas: biphasic CT versus MR imaging in tumor detection.

PURPOSE: To compare the effectiveness of biphasic computed tomography (CT) and magnetic resonance (MR) imaging in the detection of pancreatic islet cell tumors. MATERIALS AND METHODS: Retrospective quantitative, qualitative, and receiver operating characteristic analyses of biphasic CT and MR imaging were performed in 19 patients with 26 histopathologically proved islet cell tumors. Delayed arterial dominant-phase (AP) and portal venous-phase (PVP) biphasic CT was performed after the administration of contrast material. MR imaging included T1-weighted spin-echo (SE) and T2-weighted SE or fast SE imaging, fat-saturated T1-weighted SE imaging, dynamic contrast material-enhanced T1-weighted gradient-echo imaging, and delayed enhanced T1-weighted SE imaging with or without fat saturation. RESULTS: PVP CT and delayed enhanced T1-weighted MR imaging had the highest A(z) values (0.98 and 0.97, respectively; P <.05). Delayed enhanced T1-weighted MR imaging had the highest relative sensitivity (14-15 [74%-79%] of 19 lesions), followed by PVP CT (18-19 [69%-73%] of 26 lesions), AP CT (17-19 [65%-73%] of 26 lesions), fat-saturated T1-weighted MR imaging (eight to 10 [57%-71%] of 14 lesions), T2-weighted (16-17 [62%-65%] of 26 lesions), T1-weighted (15-18 [58%-69%] of 26 lesions) MR imaging, and dynamic MR imaging (nine [56%] of 16 lesions). CONCLUSION: Biphasic (especially PVP) CT and MR imaging have similar effectiveness in the detection of islet cell tumors if fat-saturated T1-weighted and delayed enhanced T1-weighted MR imaging are included.

Diagnosis of gastric cancers: comparison of conventional radiography and digital radiography with a 4 million-pixel charge-coupled device.

PURPOSE: To evaluate the differences in accuracy and observer performance at conventional radiography and at digital radiography with a 4 million-pixel charge-coupled device (CCD) for the diagnosis of gastric cancers. MATERIALS AND METHODS: A prospective study was performed of 225 patients with suspected gastric cancer who were referred to our hospital from January 1997 through February 1997. One hundred twelve patients were examined at conventional radiography and 113 were examined at digital radiography, and 24 and 27 patients had gastric cancer, respectively. Six radiologists interpreted the images, with attention to tumor findings. They were blinded to the clinical details, and their interpretations were rated against those of three other radiologists who examined the patients and who were aware of the clinical information such as endoscopic features and/or histopathologic findings in biopsy specimens. Receiver operating characteristic (ROC) analysis was used to compare the differences in observer performance for the diagnosis of gastric cancers at conventional radiography and at digital radiography. RESULTS: The overall sensitivity was 64.6% at conventional radiography versus 75.3% at digital radiography (P =. 287); specificities were 84.5% and 90.5%, respectively (P =.011); and the positive predictive values were 53.1% and 71.3%, respectively (P =.036). ROC analysis clearly showed higher diagnostic performance at digital radiography than at conventional radiography. CONCLUSION: The data demonstrate the high diagnostic value of digital radiography with a 4 million-pixel CCD for gastric cancers. The technique has considerable potential as an alternative to conventional gastrointestinal radiography.

Epithelioid hemangioendothelioma of the liver.

Epithelioid hemangioendothelioma (EH) of the liver is a rare tumor and is difficult to differentiate from cholangiocellular carcinoma or metastatic liver tumor on image diagnosis. A case of curatively resected EH of the liver is reported. A 48-year-old woman was admitted because she had a mass in the liver. Cholangiocellular carcinoma was suspected preoperatively. Right trisegmentectomy of the liver, combined with bile duct resection and portal vein resection and reconstruction, was performed. Characteristic macro- and microscopic findings of the resected specimen revealed EH of the liver. The patient has survived for more than 6 years without recurrence. Because of the tendency of EH of the liver to appear in multiple or scattered forms, only 12 cases of resection for EH have been reported.

Computerized detection of malignant tumors on digital mammograms.

This paper presents a tumor detection system for fully digital mammography. The processing scheme adopted in the proposed system focuses on the solution of two problems. One is how to detect tumors as suspicious regions with a very weak contrast to their background and another is how to extract features which characterize malignant tumors. For the first problem, a unique adaptive filter called the iris filter is proposed. It is very effective in enhancing approximately rounded opacities no matter what their contrasts might be. Clues for differentiation between malignant tumors and other tumors are believed to be mostly in their border areas. This paper proposes typical parameters which reflect boundary characteristics. To confirm the system performance for unknown samples, large scale experiments using 1212 CR images were performed. The results showed that the sensitivity of the proposed system was 90.5% and the average number of false positives per image was found to be only 1.3. These results show the effectiveness of the proposed system.

Clinical significance of magnetic resonance cholangiopancreatography for the diagnosis of cystic tumor of the pancreas compared with endoscopic retrograde cholangiopancreatography and computed tomography.

BACKGROUND: Cystic tumor of the pancreas has been investigated by a variety of imaging techniques. Magnetic resonance cholangiopancreatography (MRCP) is being widely used as a non-invasive diagnostic modality for investigation of the biliary tree and pancreatic duct system. The purpose of this study was to compare MRCP images with those of endoscopic retrograde cholangiopancreatography (ERCP) and computed tomography (CT) in order to clarify the diagnostic efficacy of MRCP for cystic tumor of the pancreas. METHODS: We retrospectively studied 15 patients with cystic tumor of the pancreas that had been surgically resected and histopathologically confirmed. There were five cases of intraductal papillary adenocarcinoma, five of intraductal papillary adenoma, two of serous cyst adenoma, two of retention cyst associated with invasive ductal adenocarcinoma and one of solid cystic tumor. RESULTS: In all cases MRCP correctly identified the main pancreatic duct (MPD) and showed the entire cystic tumor and the communication between the tumor and the MPD. On the other hand, the detection rate by ERCP of the cystic tumor and the communication between the cystic tumor and the MPD was only 60%. Although the detection rates by CT for the septum and solid components inside the cystic tumor were 100 and 90.0%, respectively, those of MRCP for each were 58.3 and 20.0%. CONCLUSION: MRCP is capable of providing diagnostic information superior to ERCP for the diagnosis of cystic tumor of the pancreas. Although MRCP may provide complementary information about the whole lesion of interest, the characteristic internal features of cystic tumor of the pancrease should be carefully diagnosed in combination with CT.

Computer-aided diagnosis in full digital mammography.

RATIONALE AND OBJECTIVES: The authors clarify the detection rates for breast cancerous tumors and clustered microcalcifications with computer-aided diagnosis (CAD) based on Fuji Computed Radiography. The authors also determine whether mammographic reading with CAD contributes to the discovery of breast cancer. METHODS: Data acquired by Fuji Computed Radiography 9000, which consisted of 4148 digital mammograms including 267 cases of breast cancer, was transferred directly to an analysis workstation where an original software program determined extraction rates for breast tumors and clustered microcalcifications. Furthermore, using another 344 mammograms from 86 women, observer performance studies were conducted on five doctors for receiver operating characteristic (ROC) analysis. RESULTS: Sensitivity to breast cancerous tumors and clustered microcalcifications were 89.9% and 92.8%, respectively false-positive rates were 1.35 and 0.40 per image, respectively. The observer performance studies indicate that an average Az value for the five doctors was greater with the CAD system than with a film-only reading without CAD, and that a reading with CAD was significantly superior at P < 0.022. CONCLUSIONS: It has been shown that CAD based on Fuji Computed Radiography offers good detection rates for both breast cancerous tumors and clustered microcalcifications, and that the reading of mammograms with this CAD system would provide potential improvement in diagnostic accuracy for breast cancer.

Usefulness of magnetic resonance imaging with dynamic contrast enhancement and fat suppression in detecting a pancreatic tumor.

The purpose of this study was to compare the value of dynamic magnetic resonance imaging (MRI) and fat suppression in detecting a pancreatic tumor. The subjects were 19 patients with invasive ductal adenocarcinoma and six patients with islet cell tumor where diagnosis was established pathologically. Breath-hold gradient echo images, breath-hold gradient echo images with fat suppression and breath-hold gradient echo images with dynamic enhancement at 1.5 T were obtained for all patients. The efficacies of these three imaging techniques were compared by calculating the contrast-to-noise ratio, as indicative of conspicuousness between a tumor-affected and a normal pancreas. As for adenocarcinoma, our results indicated that the usefulness in detecting the tumor was high, decreasing in the order dynamic contrast images > fat suppression images > plain images, and that the difference between any two of these three types of image was statistically significant. On the other hand, these imaging techniques showed no statistically significant difference in detecting islet cell tumors. In conclusion, dynamic MRI is the best method for detecting pancreatic adenocarcinoma. As the fat suppression technique has the advantage of being non-invasive, this method is suitable for screening studies of pancreatic adenocarcinoma. However, no advantage was recognized in using the fat suppression technique for detecting an islet cell tumor in comparison with plain MRI.

[Staging of pancreatic ductal adenocarcinoma using dynamic MR imaging].

Single breath-hold gradient echo images were obtained before and immediately after bolus intravenous administration of Gd-DTPA (dynamic MR imaging) in the study of the pancreas. Of 37 patients with pathologically proved pancreatic ductal adenocarcinoma, seventeen patients who underwent both dynamic MR imaging studies and curative surgery were included in this study. Correlations between histologic findings in the resected specimens and MR images were analyzed as to tumor extension and staging according to the General Rules for the Study of Pancreatic Cancer (4th Edition) published by the Japan Pancreas Society. In comparison with conventional MR images, dynamic MR imaging improved the detectability of pancreatic carcinoma and delineation of the vasculature by clarifying the margin of the tumor and the vessels. Nonenhanced T1-weighted imaging is the best sequence to estimate peripancreatic tumor extension, because the contrast between the tumor and peripancreatic fat deteriorates with the use of contrast material. There is a tendency to overestimate vascular invasion on MR images, the reason for which is considered to be the contractive nature of fibrotic change induced by pancreatic carcinoma. The diagnostic efficacy of lymph node metastasis remains insufficient on MR images because some cases show no enlargement of lymph nodes in spite of the existence of pathological metastasis. Our results suggest that dynamic MR imaging has the advantage of improving the conspicuity of the tumor and the vasculature.

Cine magnetic resonance imaging, computed tomography and ultrasonography in the evaluation of chest wall invasion of lung cancer.

PURPOSE: To assess the usefulness of cine-magnetic resonance imaging (cine-MRI)in the evaluation of chest wall invasion, we compared the results of cine-MRI with those of computed tomography (CT) and ultrasonography (US). MATERIALS AND METHODS: Eleven patients were examined who had no pain and who were difficult to diagnose by routine examinations. MRI was performed with a Magnetom SP/4000, 1.5T unit (Siemens, Germany). For cine imaging, continuous turbo-FLUSH (ultra fast low angle shot) images were obtained at an orthogonal section to the chest wall during slow deep breathing. A CT scan was performed using a TCT 900S or Super Helix (Toshiba, Japan) at 1 cm intervals, with section thicknesses of 1 cm throughout the entire chest. US was performed with a model SSA-270A (Toshiba, Japan) with 7.5-MHz linear array scanners (PLF-705S; Toshiba, Japan). RESULTS: Sensitivity, specificity and accuracy were 67%, 75% and 73% for cine MRI, 67%, 63% and 64% for CT, 33%, 75% and 64% for US, respectively. CONCLUSIONS: These results indicate that cine MRI is potentially useful for the diagnosis of chest wall invasion of lung cancer.

Intracranial metastases of hepatocellular carcinoma: CT and MRI.

We report clinical characteristics and CT and MRI in 16 patients with brain metastases due to hepatocellular carcinoma (HCC). Eight of these 16 patients presented with apoplexy-like symptoms (50%). Pulmonary metastases were found in 13 cases (81.3%). The mean survival from the appearance of cerebral metastases to death was 6.2 weeks, which is one of the shortest survival terms in metastatic brain tumours. Haemorrhagic brain metastases were observed in 14 patients (87.5%) with a tendency for the frequency of bleeding to increase in proportion to the size of the tumour. On both contrast-enhanced CT and MRI, metastatic brain tumours enhanced strongly, suggesting that brain metastases, like HCC, are also hypervascular. MRI is useful in evaluating brain metastases from HCC, especially in order to differentiate tumour from haemorrhage. Our results demonstrated a poor prognosis and bleeding tendency of brain metastases due to HCC and showed the usefulness of CT and MRI in achieving a correct diagnosis.

Evaluation of digital mammography in diagnosis of breast cancer.

Mammography has been digitized in all cases at our hospital. Digital mammography (MMG) of our hospital and its diagnostic accuracy were described in this report. Fuji Computed Radiography (FCR; Fuji Medical Systems, Tokyo, Japan) imaging plate was used and imaging data were processed with FCR 7000 or FCR 9000. Each image was output to a single hard copy. Sampling pitches for reading and output were 0.1 mm. The rate of breast cancer diagnosis by digital MMG was 67%, 95%, 94%, and 100% for unpalpable tumor, tumor less than phi 2 cm, tumor of phi 2 to 5 cm, and tumor greater than phi 5 cm, respectively, being 94% overall. Digital MMG enables us to establish goal-oriented image-processing conditions. The use of digital MMG, which provides an excellent diagnostic rate similar to that of screen-film MMG, is expected to became wide-spread in the near future.

Cine MRI in radiotherapy treatment planning of brain tumors.

This paper presents our preliminary experience with three-dimensional (3-D) treatment planning using the cine mode display of magnetic resonance imaging (MRI) for brain tumors. MRI images, viewed from the direction of the source of radiation, are reconstructed at consecutive 5 mm intervals and superimposed on the 3-D skin surface image. Tumors and normal structures can be visualized as is, without delineating them. Limitations of the technique are also discussed.

[Hepatoblastoma: clinico-radiological study of fifteen cases].

From January 1976 to October 1989, 15 patients with hepatoblastoma who underwent surgery at the National Cancer Center Hospital were evaluated by clinico-radiological techniques. Eight patients were boys and seven were girls; their average age was 3 years and 5 months. Abdominal mass or distention was initially noted in 12 patients. Alpha-fetoprotein level was extremely high (average, 327 micrograms/ml) in all cases but one. Hepatitis B surface antigen was negative in all cases. Tumors occupied mainly the right lobe of the liver in 67% of patients, and the mean tumor diameter was 11.1 cm. Of 15 hepatoblastomas, 10 were grossly classified as massive type and five as multinodular. Histopathological diagnosis was well differentiated (fetal type) hepatoblastoma in 10 patients and poorly differentiated (embryonal type) hepatoblastoma in five. Fibrous capsule was also recognized in eight. The noncancerous liver was normal in all cases. Ultrasonography (US) (n = 7 patients) demonstrated an inhomogeneous internal echo with well demarcated margin in five cases and without such margin in two. Nonenhanced CT (n = 6) showed an isodense or low density mass in all cases. Drip infusion CT (n = 5) revealed isodensity in the early phase. Dynamic CT performed in one patient showed a well enhanced mass that appeared hypervascular on angiography. Preoperative chemotherapy and radiation therapy provoked histological changes such as necrosis, fibrosis and calcifications. These changes were reflected on CT images. Both US and CT demonstrated the characteristic internal structure and gross appearance of hepatoblastoma.

Early hepatocellular carcinoma: MR imaging.

All areas in hepatic lesions designated as adenomatous hyperplasia (AH) with malignant foci have recently been recognized as cancer. AH with malignant foci can be classified into two types, depending on the presence of overt cancerous nodules. Lesions without macroscopic nodules are defined as early hepatocellular carcinoma (HCC), while those with a macroscopic component are defined as HCC with early components. A comparative study of early HCC and HCC with early components was performed with magnetic resonance imaging. Early HCC lesions (n = 20) were isointense (n = 11) and hyperintense (n = 9) on T1-weighted spin-echo images and isointense (n = 17), partially hyperintense (n = 2), or hypointense (n = 1) on T2-weighted spin-echo images relative to the surrounding liver. Lesions classified as HCC with early components (n = 8) were hyperintense (n = 5), isointense (n = 2), and of mixed signal intensity (n = 1) on T2-weighted images. T1-weighted imaging was superior to T2-weighted imaging in depicting early HCC, but the latter could be useful in evaluating the progression of HCC in the histopathologically early stages.

[Clinical application of helical scanning CT of upper abdomen].

The helical scanning CT unit, in which an X-ray tube continuously rotates at the rate of one revolution per second with constant movement of the table on which the patient is placed, was clinically tested in scanning of upper abdomen. Quality of the images obtained was equal to that of conventional CT. The images were particularly good at an X-ray beam width of 5 mm and table movement of 5 mm/sec with scan parameters of 120 kvp, 200 mA. Because of limitation of the X-ray tube capacity. X-ray beam width of 5 mm and table movement of 10 mm/sec with scan parameters of 120 kvp, 150 m, would be the most appropriate clinically. Application of the helical scanning CT will result in examination times shorter than in the case of conventional high-resolution CT and be obtained images at early vascular enhancement phase through the whole scanning area, so that it can be expected to be extremely useful in clinical diagnosis involving upper abdomen.