Biomedical subjects
Publications and source records attributed to Masahiko Fujii.
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BACKGROUND: Over 355 patients have received orthotopic liver transplantation (OLT) at this hospital since 1993. Preoperative imaging studies of both hepatic vessels and parenchyma in these recipients bettered surgical planning or even precluded the necessity of surgery. Here we report our preliminary results of modified magnetic resonance angiography (MRA) using sensitivity encoding (SENSE) through comparative study with conventional digital subtraction angiography (DSA) and CT arterial portography (CTAP). METHODS: Sixteen patients with suspected liver diseases were included in the study. All of them received both dynamic MRI of the liver using SENSE and digital DSA with CTAP within a two-week interval. The four-phase MRA was reconstructed from source images of the coronal dynamic study. The arterial phase of the modified MRA was compared with DSA in the evaluation of hepatic arteries and the portal phase compared with CT portography reconstructed from source images of CTAP. In dynamic study of the liver, a fixed dose (20 ml) of contrast medium and scan timing were used. RESULTS: The main branches and variations of the hepatic arterial system were well shown on the modified MRA, although the marginal branches of hepatic arteries were of poor quality. The figures of portal veins on MRA were as clear as or superior to those of CTAP. In addition, the suprarenal inferior vena cava (IVC) was well demonstrated on MRA and/or non contrast-enhanced coronal balanced fast-field echo (b-FFE) scan sequence in most cases. MRI detected most parenchymal lesions of the liver and hemodynamics of these lesions could be evaluated on source images of the modified MRA. MRI/MRA also serendipitously revealed several extrahepatic disease entities or variations that were not found on DSA/CTAP. CONCLUSIONS: The modified MRA using SENSE is a cost-effective modality of examination for the demonstration of the whole hepatic vascular system. Combined with MRI, it has the potential as a one-stop imaging modality in the preoperative evaluation in fields such as OLT.
PURPOSE: To evaluate the diagnostic capability of contrast-enhanced multidetector computed tomography (MDCT) for the preoperative assessment of musculoskeletal masses, in comparison with magnetic resonance imaging and plain radiographs (MRI+X-p). MATERIALS AND METHODS: Sixty-eight patients with musculoskeletal masses underwent plain radiography, MRI, and contrast-enhanced MDCT. The following five items were evaluated for all images: histological properties, vascularity, neurovascular involvement, calcification/ossification, and cortical/marrow involvement. The MDCT images with three-dimensional reconstruction were retrospectively compared with MRI+X-p. RESULTS: In 32 bone lesions, MDCT was superior/equal/inferior to MRI+X-p regarding histological properties in 4/10/18, vascularity in 0/11/21, neurovascular involvement in 0/26/6, calcification/ossification in 15/17/0, and cortical/marrow involvement in 29/3/0 cases, respectively. In 36 soft-tissue lesions, MDCT was superior/equal/inferior to MRI+X-p with histological properties in 1/18/17, vascularity in 0/12/24, neurovascular involvement in 1/24/11, calcification/ossification in 8/28/0, and cortical/marrow involvement in 7/29/0 cases, respectively. The MDCT evaluation of both calcification/ossification and cortical/marrow involvement in bone lesions was superior to that in soft-tissue lesions (p<0.05). There were no statistically significant differences between benign and malignant lesions in the evaluation of each of the five items. CONCLUSION: MDCT provided additional and more comprehensive information than MRI+X-p for the preoperative assessment of musculoskeletal masses, especially for calcification/ossification and cortical/marrow involvement. Three-dimensional contrast-enhanced MDCT images can be adopted equally to MRI for the preoperative evaluation of neurovascular involvement.
BACKGROUND: Bloody nipple discharge is a significant clue in the detection of ductal carcinoma of the breast. In the past, pathologic diagnoses were obtained exclusively via excision, but recently developed mammoscopic techniques have been found to yield valuable information relating to the diagnosis of intraductal lesions. METHODS: Mammary duct endoscopy (i.e., mammoscopy) was performed a combined total of 407 times for 295 patients who experienced nipple discharge. Intraductal breast biopsy (IDBB) under mammoscopic observation was performed in 193 intraductal papillomas (from a total of 107 patients) and 30 ductal carcinomas (from a total of 27 patients); IDBB was performed a combined total of 36 times in the 27 patients who had breast carcinoma and yielded 21 diagnostic specimens (58.3%). In addition, the therapeutic value of IDBB was assessed in 70 patients with intraductal papilloma who had undergone more than 3 years of follow-up; these 70 patients harbored a combined total of 75 intraductal papillomas. RESULTS: IDBB correctly identified the presence of carcinoma in 9 of 27 patients (33.3%); 7 other lesions (25.9%) were placed in the suspected carcinoma (i.e., atypical papillary lesion) category, and 5 (18.5%) were identified as intraductal papillomas. Using IDBB, it was difficult to collect diagnostic specimens from patients with breast carcinoma, because of the location and weak tissue cohesiveness of these lesions compared with intraductal papillomas. The 193 intraductal biopsies performed on intraductal papillomas yielded only 20 specimens that were insufficient for diagnosis. IDBB exhibited therapeutic efficacy in 54 of 70 patients with intraductal papilloma (77.6%) who had more than 3 years of clinical follow-up. Therapeutic results tended to be less favorable for patients who had intraductal lesions in multiple duct lobular units. CONCLUSIONS: Mammoscopy can contribute not only to the diagnosis of cases of nipple discharge but also to the treatment of intraductal papilloma.
PURPOSE: To assess regional differences in quantitative pulmonary perfusion parameters, i.e., pulmonary blood flow (PBF), mean transit time (MTT), and pulmonary blood volume (PBV) in the entire lung on a pixel-by-pixel basis in normal volunteers and pulmonary hypertension patients. MATERIALS AND METHODS: Three-dimensional ultrafast dynamic contrast-enhanced MR imaging was performed in 15 normal volunteers and 25 patients with pulmonary hypertension. From the signal intensity-time course curves, PBF, MTT and PBV maps were generated using deconvolution analysis, indicator dilution theories, and the central volume principle, on a pixel-by-pixel basis. From pulmonary perfusion parameter maps of normal volunteers and pulmonary hypertension patients, regional PBF, MTT, and PBV were statistically evaluated. RESULTS: Regional PBF, MTT, and PBV showed significant differences in the gravitational and isogravitational directions (P < 0.05). The quantitative pulmonary perfusion parameter maps demonstrated significant differences between normal volunteers and pulmonary hypertension patients (P < 0.05). CONCLUSION: Three-dimensional ultrafast dynamic contrast-enhanced MR imaging is feasible for the assessment of regional quantitative pulmonary perfusion parameters in the entire lung on a pixel-by-pixel basis in normal volunteers and pulmonary hypertension patients.
PURPOSE: To determine the utility of dynamic magnetic resonance imaging (MRI) in the differential subtyping of small adenocarcinomas of the lung. MATERIALS AND METHODS: Twenty-nine pathologically diagnosed peripheral adenocarcinomas (less than 20 mm in diameter) underwent dynamic contrast-enhanced MRI. Maximum relative enhancement ratio, slope of enhancement, and corrected start time of enhancement were calculated from signal intensity-time curve of pulmonary lesion for each subject, and were statistically compared among bronchioloalveolar carcinoma (BAC) group (7 cases), mixed BAC group (10 cases), and adenocarcinoma group (12 cases). RESULTS: Maximum relative enhancement ratio (P<0.001) and slope of enhancement (P<0.001) of BAC group were significantly higher than those of mixed BAC and adenocarcinoma groups. Start times of BAC group were significantly earlier than those of mixed BAC (P=0.0001) and adenocarcinoma groups (P<0.0001). Adapting the thresholds values of MR indexes from the positive tests, sensitivity, specificity, positive predictive value, negative predictive value and accuracy for differentiating BAC from other subtypes were 85.7, 100.0, 100.0, 95.7, and 96.6%, respectively. CONCLUSIONS: Dynamic MRI is useful for differentiating subtypes of small peripheral adenocarcinoma.
OBJECTIVE: The aim of our study was to determine the utility of time-resolved contrast-enhanced MR angiography combined with sensitivity encoding (SENSE) for patients with pulmonary embolism. SUBJECTS AND METHODS. Forty-eight consecutive patients (26 men and 22 women; age range, 27-73 years; mean age, 55 years) with suspected pulmonary embolism underwent chest radiography, contrast-enhanced MDCT, MR angiography with SENSE, ventilation-perfusion scintigraphy, and pulmonary angiography. MR angiography with SENSE was performed using IV administration of gadolinium contrast medium with a 3D turbo field-echo pulse sequence (TR/TE, 4.0/1.2; flip angle, 30 degrees ) on a 1.5-T scanner. Capabilities of diagnosing pulmonary embolism using MR angiography (data set A), contrast-enhanced MDCT (data set B), contrast-enhanced MDCT with MR angiography (data set C), ventilation-perfusion scintigraphy (data set D), and contrast-enhanced MDCT with ventilation-perfusion scintigraphy (data set E) were determined by receiver operating characteristic analysis, using the results of pulmonary angiography as the reference standard. The diagnostic capability of each data set was analyzed on a per-vascular zone and a per-patient basis with the McNemar test. RESULTS: Sensitivity and specificity of data set A were 83% and 97%, respectively, on a per-vascular zone basis and 92% and 94%, respectively, on a per-patient basis. Specificity and accuracy of data set A were significantly higher than those of data set D on a per-patient basis (p < 0.05). CONCLUSION: Time-resolved MR angiography with SENSE is effective for the diagnosis of pulmonary embolism.
Spontaneous rupture is a major life-threatening complication of hepatocellular carcinoma(HCC). Ruptured HCC often causes hypovolemic shock and hepatic hypoperfusion. Patients with impaired liver function tend to lapse into liver failure, which is the main cause of death. To prevent liver failure, accurate diagnosis and adequate treatment for the restoration of the efficient liver perfusion are required. Emergent transarterial embolization (TAE) is the most effective and less-invasive treatment for hemostasis. On the other hand, emergent hepatic resection should be avoided because of the increased risk of postoperative liver failure and incomplete resection of the tumor. After achieving hemostasis, a second-stage therapeutic approach for HCC is required. Patients with acceptable liver function should undergo surgery. The prognosis of ruptured HCC treated with second-stage hepatectomy is considered to be comparable with that of nonruptured HCC. In conclusion, spontaneous rupture of HCC is considered to be a combination of acute and severe peritoneal hemorrhage with malignant disease. To improve the prognosis, adequate early treatment for the control of hemorrhage while preserving liver function is an important factor. TAE followed by elective hepatectomy is considered the most effective treatment.
Small-for-size (SFS) graft syndrome is an important problem after living-donor liver transplantation in adults. Hemodynamic change is thought to be the main cause of graft injury. Excessive portal flow is associated with hepatic sinusoidal injury, and reduction of portal flow improves postoperative liver function. Increased venous outflow due to hepatic venoplasty or reconstruction of the middle hepatic vein decrease the risk of graft congestion. However, the intragraft acute-phase response remains unclear. Recent studies have revealed that downregulation of heat shock protein (HSP) may account for SFS graft injury, and induction of HSP may prevent SFS syndrome. On the other hand, derangement in the regulation of liver regeneration is recognized as another important factor. Further investigation of the regulatory mechanisms of liver regeneration in SFS grafts may suggest a strategy for the prevention and treatment of SFS syndrome. Successful transplantation of marginal-size liver grafts would improve outcome for recipients and increase the margin of safety for living donors.
STUDY DESIGN: A case study of an extradural arachnoid cyst using kinematic magnetic resonance imaging. OBJECTIVES: To access the dynamic and pathologic changes of an extradural subarachnoid cyst during straining by kinematic magnetic resonance imaging and to clarify the pathomechanism of a fluctuation in symptoms. SUMMARY OF BACKGROUND DATA: Extradural arachnoid cysts of the spine are an uncommon cause of myelopathy secondary to spinal cord compression; however, the precise mechanism of cord compression and subsequent symptoms remain unclear. METHODS: A 31-year-old female presented with severe left lower thoracic back pain and leg stiffness, which were exacerbated by coughing and straining. She was diagnosed with an extradural subarachnoid cyst by magnetic resonance imaging. Kinematic magnetic resonance imaging was carried out to assess the dynamic change of the extradural cyst and to demonstrate the mechanism causing her chest pain and leg stiffness during straining. RESULTS: Kinematic magnetic resonance imaging demonstrated that the cyst wall was compressed, and the size of extradural cyst was decreased for several seconds during straining. Furthermore, the ring of cerebrospinal fluid was gradually compressed circumferentially. After surgery, the patient experienced complete relief of symptoms. Postoperative kinematic magnetic resonance imaging revealed good decompressive results had been obtained, and the ring of cerebrospinal fluid was preserved even when the patient strained for a few minutes. CONCLUSIONS: Kinematic magnetic resonance imaging study demonstrated that pressure changes which occur in the extradural space as well as in the arachnoid cyst might cause spinal cord compression and result in intermittent exacerbation of symptoms.
PURPOSE: Information concerning the amount and nature of target motion is essential for the determination of internal margin size. However, there are few published reports outlining the motion with heart and aortic pulsation. We introduce a method for three-dimensional radiation treatment planning (3D-RTP) by using electrocardiographically (ECG) gated spiral scanning with a four-section CT system. We describe a new approach to visualize internal organ motion resulting from cardiac motion with ECG gated multidetector row CT. MATERIALS AND METHODS: Five patients with lung or liver tumors were studied with a multidetector row CT system under shallow inspiration breath-holding. With retrospective ECG gating, only data acquired within a predefined interval of the cardiac cycle are used for image reconstruction. All reconstructed image data at diastolic and systolic phases of the cardiac cycle were transferred to the 3D-RTP system. The shift of the internal organs between the cardiac cycles was evaluated. RESULTS: Cardiac contraction influences anterior thorax, pulmonary peripheral vessels, and liver position, in addition to locations near the heart. Apparent movements more than 5 mm between diastolic and systolic phases were observed in the left ventricle, right atrium, and superior vena cava. Two-phase imaging was useful for showing the movement of internal organs during cardiac contraction under breath-holding. CONCLUSIONS: Spatial information using ECG-gated CT has the potential to determine the planning target volume of moving lung and liver tumors more precisely than conventional CT planning.
PURPOSE: To evaluate the relationship between gadolinium concentration and signal-to-noise ratio (SNR) on sensitivity encoding (SENSE) images, and determine the appropriate bolus injection protocol for visualizing pulmonary circulation. MATERIALS AND METHODS: Eighteen different gadolinium concentration phantoms (0, 0.01, 0.05, 0.1, 0.2, 0.4, 0.6, 0.8, 1.0, 1.2, 1.5, 2.0, 5.0, 10.0, 20.0, 30.0, 50.0, and 100.0 mmol/L) were analyzed to determine the relationship between gadolinium concentration and SNR on SENSE images in a phantom study. In an in vivo study, 3 mL (protocol A) or 6 mL (protocol B) of Gd-DTPA BMA at 3 mL/second, and 5 mL of Gd-DTPA BMA at 5 mL/second (protocol C) were administered to eight normal volunteers for contrast-enhanced (CE) pulmonary MR angiography (MRA) with SENSE. The peak SNRs of pulmonary parenchyma and the difference in SNR between pulmonary artery (PA) and pulmonary vein (PV) at peak SNR in the PA were statistically evaluated. RESULTS: For each flip angle at each gadolinium concentration, the SNRs and contrast-to-noise ratios (CNRs) of the SENSE images were significantly lower than those acquired with a nonparallel imaging technique (P < 0.05). The peak SNR of the pulmonary parenchyma, and differences in SNR between the PA and PV at the peak SNR of the PA obtained with a 5-mL/second bolus injection protocol were found to be significantly higher than those obtained with other protocols (P < 0.05). CONCLUSION: 3D-CE-MRA using SENSE demonstrated linearity between gadolinium concentration and SNR, and resulted in MRA with high spatial and temporal resolution with the aid of a sharp bolus injection protocol.
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INTRODUCTION: Despite various treatment trials for unresectable pancreatic carcinoma with liver metastases, the outcome has not been satisfactory. This paper reports a case of pancreatic carcinoma with multiple liver metastases that responded well to arterial infusion chemotherapy. CASE REPORT: A 65-year-old male was diagnosed with multiple liver tumors, and needle biopsy revealed adenocarcinoma. With endoscopic ultrasonography, a tumor in the pancreatic head was detected, and pancreatic carcinoma with multiple liver metastases was diagnosed. He received arterial infusion chemotherapy: cisplatin at a dose of 10 mg/body/day and 500 mg/body/day of 5-fluorouracil After 14 days administration, liver metastases had decreased in number and size, but thereafter, because of hepatic arterial occlusion, the same dose of drugs was administered intravenously. The patient was discharged from the hospital and was given chemotherapy 3 days a week on an outpatient basis. Although the chemotherapy was effective, it was stopped because of severe general fatigue 5 months after discharge. His general status continued to gradually worsen, and he died 12 months after diagnosis. CONCLUSIONS: Prognosis of pancreatic carcinoma with liver metastases is poor; however, transarterial infusion chemotherapy may be effective to improve the prognosis and quality of life of the patients.
PURPOSE: To compare the diagnostic ability of proton magnetic resonance spectroscopy (MRS) using an external surface coil with that using an endorectal surface coil in patients with prostate cancer. MATERIALS AND METHODS: MR imaging (MRI) and two-dimensional chemical shift imaging (2D CSI) were performed in 5 healthy volunteers and in 35 patients with prostate cancer. The receiver coil was the anterior lower part of a phased-array coil or an endorectal surface coil. RESULTS: Receiver-operating characteristic analysis for diagnosing prostate cancer showed no significant difference (P = 0.784) between the area under the curve of phased-array coil CSI and that of endorectal surface coil CSI. CONCLUSION: The phased-array coil CSI could provide comparable detection accuracy to endorectal surface coil CSI. In patients with rectal diseases or patients who could not tolerate the discomfort with insertion of an endorectal surface coil, we recommend the phased-array coil CSI.
The purpose of this study was to demonstrate the feasibility of dynamic oxygen-enhanced MRI in a clinical setting. We hypothesized that dynamic oxygen enhancement can reflect the regional diffusing capacity of the lung. Ten patients with pulmonary emphysema and seven healthy volunteers were examined with a respiratory-synchronized inversion recovery single-shot turbo spin-echo sequence (TR = 3200-5000 ms, TE = 16 ms, TI = 720 ms, ETS = 4 ms) following 100% oxygen inhalation, using a 1.5 T whole-body scanner. Maximum mean relative enhancement ratios calculated by averaging six defined regions of interest (ROIs) in both lungs were statistically compared between healthy volunteers and patients, and were correlated with diffusing lung capacity (%DL(CO)). In patients with pulmonary emphysema, maximum mean relative enhancement ratios were significantly decreased compared to those in healthy volunteers (P = 0.0008). Maximum mean relative enhancement ratio had excellent correlation with % DL(C0) (r(2) = 0.83). Dynamic oxygen-enhanced MRI may reflect the diffusing capacity of the lung; therefore, imaging of oxygen enhancement with MRI may provide maps of the diffusing capacity.
Gastric inverted hyperplastic polyp (IHP) is a rare type of gastric polyp, and is characterized by downward growth of the hyperplastic mucosal components into the submucosa. To the best ofour knowledge, 16 gastric IHP cases have been described in the English literature, but the pathogenesis has not been established. We report the clinical and pathological findings of four gastric IHP cases. The lesions were mainly composed of hyperplastic foveolar-type glands with focal cystic dilatation. Pyloric type glands, endocrine cells, acinic cell metaplasia, and smooth muscle bundles were also seen as components of the polyp. Two cases (cases 1 and 4) coexisted with multifocal gastritis cystica profunda (GCP) and gastric adenocarcinoma. Case 4 furthermore exhibited an intermediate form between IHP and GCP. We suggest that IHP may be GCP associated with exaggeratedly hyperplastic and metaplastic changes. In case 4, the coexisting gastric carcinoma was mainly located in the submucosa, whilst the mucosal component was minimal. Five out of twenty reported gastric IHP cases, including our cases, coexisted with gastric adenocarcinoma. These facts would lead us to further investigate the relation between gastric IHP and carcinoma.
We report two cases of gastric varices complicated by massive ascites that disappeared after balloon-occluded retrograde transvenous obliteration (B-RTO). The first patient had progressive gastric varices that continued to enlarge even after three episodes of esophagogastric variceal bleeding, and the second patient was admitted to our hospital because of the bleeding from gastric varices. After B-RTO procedures in both patients, significant improvement of the ascites, hepatic function reserve, and hypoalbuminemia was observed. Although further experience is needed, our experience points to the likelihood of the amelioration of ascites after B-RTO.