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Biomedical subjects

J Hachiya

Publications and source records attributed to J Hachiya.

At least 37 records · Page 2Linked to original sources
PubMed1998

Limb salvage and survival rates among elderly patients with advanced limb ischemia.

The purpose of this study was to clarify the incidence of limb salvage and patient survival rates among elderly patients with advanced leg ischemia. We reviewed the records of 159 patients treated for advanced ischemia over a 15-year period at Aichi Medical University, 74 of whom were aged over 75 years and 85, between 65 and 74 years. There was a collective total of 186 limbs; 82 in the older group and 104 in the younger group. The older group had a greater proportion of women, and a higher incidence of coronary heart disease, pulmonary dysfunction, and acute onset of advanced ischemia than the younger group. Limb salvage was achieved in 73% of the affected limbs in the older group and in 92% of the limbs in the younger group. The poor limb salvage rate in the older group was mainly related to the high initial amputation rate. Early recognition of the sentinel ischemic signs before the ischemia is essential, especially in the elderly. Timely revascularization should be attempted whenever possible, and it should not be abandoned simply because the patient is deemed too old. The 1-, 3-, and 5-year survival rates in the older group were 59%, 28%, and 23%, respectively, which were markedly poorer than the expected survival rates of the age- and sex-matched Japanese population at 1, 3, and 5 years, which were 93%, 79%, and 65%, respectively. Thus, advanced limb ischemia carries a poor prognosis to the point of being life-threatening, and further continuous systemic management with the collaboration of physicians and surgeons must be provided even after the patient has left the hospital.

Aged↗
PubMed1998

Intraductal papillary tumors of the pancreas: evaluation with magnetic resonance cholangiopancreatography.

OBJECTIVE: We analyzed the findings of intraductal papillary tumors of the pancreas by magnetic resonance cholangiopancreatography (MRCP). METHODS: Twelve patients with intraductal papillary tumors (main duct type, n = 3; branch duct type, n = 8; combined type, n = 1) underwent endoscopic retrograde cholangiopancreatography (ERCP) (n = 11) and MRCP, using half-Fourier acquisition single-shot turbo spin-echo (HASTE) sequences (n = 12). Imaging findings were compared with operative and pathological findings in all the patients. RESULTS: Although ERCP failed to fully depict the main pancreatic duct and cystic tumors in six of 11 patients because of copious intraductal mucin, MRCP provided complete images of these structures in all 12 patients. In main duct type tumors, MRCP demonstrated moderate-marked, diffuse dilation of the main pancreatic duct. Branch duct type tumors showed "grape-like" clusters of cysts with no or only mild, diffuse dilation of the main duct. In combined type tumors, MRCP demonstrated a markedly dilated main duct with a large unilocular cyst of the collateral duct. MRCP detected more mural nodules (75%, three of four patients) than ERCP (25%, one of four). MRCP allowed more precise diagnosis of the type, size, and extent of tumors than ERCP, as confirmed by pathologic findings. CONCLUSION: MRCP demonstrates intraductal papillary tumors less invasively and more completely than ERCP.

Adenocarcinoma, Papillary↗
PubMed1998

Magnetic resonance cholangiography using half-Fourier acquisition for diagnosing choledocholithiasis.

OBJECTIVE: Magnetic resonance cholangiography (MRC), using a half-Fourier acquisition single-shot turbo spin-echo (HASTE) sequence, noninvasively provides very rapid (1-2 s) and high-quality images of the biliary tract. We assessed the diagnostic usefulness of HASTE-MRC for choledocholithiasis. METHODS: A total of 101 patients with suspected choledocholithiasis underwent MRC, ultrasonography, and endoscopic retrograde cholangiopancreatography (ERCP). In 97 patients in whom ERCP fully depicted the common bile duct, we retrospectively analyzed the capability of MRC to image the common bile duct and to diagnose choledocholithiasis, in comparison with that of ultrasonography. RESULTS: In 34 patients, ERCP demonstrated bile duct stones, which were confirmed at endoscopic or surgical treatment. The common bile duct was fully delineated in 98% by MRC and in 70% by ultrasonography. MRC (91%) was more sensitive than ultrasonography (71%) for detecting choledocholithiasis (p < 0.05). MRC demonstrated bile duct stones in all patients with stones > or =11 mm but missed calculi in the 29% of patients with small (3-5 mm) stones. MRC was capable of detecting choledocholithiasis regardless of bile duct caliber. The specificity of MRC (100%) was higher than that of ultrasonography (95%). CONCLUSION: HASTE-MRC, a fast and noninvasive procedure, can accurately diagnose choledocholithiasis although the detectability for small stones is limited.

Cholangiopancreatography, Endoscopic Retrograde↗
PubMed1998

Diffusion-weighted MR imaging with a single-shot echoplanar sequence: detection and characterization of focal hepatic lesions.

OBJECTIVE: The purpose of this study was to determine the usefulness of diffusion-weighted MR imaging with single-shot echoplanar imaging in characterizing focal hepatic lesions by apparent diffusion coefficient (ADC) and contrast-to-noise ratio (CNR) measurements. MATERIALS AND METHODS: Diffusion-weighted imaging on a 1.5-T MR unit was performed in 46 patients with 74 known focal hepatic lesions (11 hemangiomas, 15 metastases, and 48 hepatocellular carcinomas [HCCs]). Mean values for ADCs and CNRs of all lesions were calculated. Mean values for CNRs with diffusion-weighted imaging were also compared with those for breath-hold T2-weighted fast spin-echo images. RESULTS: The mean values for ADCs were different for each type of tumor (5.39 x 10(-3) mm2/sec +/- 1.23 in hemangiomas, 2.85 x 10(-3) mm2/sec +/- 0.59 in metastases, and 3.84 x 10(-3) mm2/sec +/- 0.92 in HCCs), and each of them was significantly greater than the mean values for ADCs of the normal liver (2.28 x 10(-3) mm2/sec +/- 1.23 in normal liver [p < .05] except metastasis versus normal liver [p < .1]). Also, the mean values for ADCs were based on differences of ADC values. Only four (6%) of 63 malignant tumors (three HCCs and one metastasis) could not be differentiated from hemangiomas. The mean value for CNRs with diffusion-weighted images (14.4 +/- 8.54 in HCC and 29.0 +/- 6.79 in metastasis) was significantly higher than the mean values for CNRs obtained with T2-weighted fast spin-echo images in both metastases and HCCs (p < .05), whereas no significant difference was seen for hemangiomas. CONCLUSION: Mean values for ADCs differed for the three types of the hepatic lesions and were higher than ADCs of the normal liver. We suggest that diffusion-weighted imaging may be useful for increased detection of HCCs and metastases and in distinguishing these entities from hemangiomas.

Carcinoma, Hepatocellular↗
PubMed1998

Characterization of hepatic lesions by perfusion-weighted MR imaging with an echoplanar sequence.

OBJECTIVE: The purpose of this study was to examine the usefulness of perfusion-weighted MR imaging with a single-shot gradient echoplanar sequence in characterizing hepatic tumors. SUBJECTS AND METHODS: Perfusion-weighted imaging was performed in 61 patients with 91 confirmed hepatic tumors (14 hemangiomas, 19 metastases, and 58 hepatocellular carcinomas). The perfusion-weighted imaging was started at the time of administration of 0.1 mmol/kg of gadolinium, and images were continuously obtained every 2 sec for 88 sec. Time-intensity curves for all the tumors were created for quantitative analysis. Patterns of enhancement were also evaluated. RESULTS: Changes in signal intensity that occurred throughout examination differed in three types of tumor. Transient signal intensity decreases in the perfusion phase significantly differed in three types of tumors (46% in hepatocellular carcinoma, 48% in hemangioma, and 15% in metastasis, p < .05 for hepatocellular carcinoma versus metastasis and for hemangioma versus metastasis). Signal intensity recovered rapidly for hepatocellular carcinoma and metastasis, whereas recovery was slower for hemangioma. Final signal intensity recovery was 94% in hepatocellular carcinoma, 91% in metastasis, and 54% in hemangioma compared with their initial signal intensities. (p < .05 for hepatocellular carcinoma versus hemangioma and for hemangioma versus metastasis.) The enhancement patterns also differed in three types of tumor. CONCLUSION: Perfusion-weighted imaging with a gradient echoplanar sequence provides real-time mapping of many points along the enhancement profile curves because of its excellent temporal resolution. Therefore, it accurately characterizes hepatic tumors based on their different negative-enhancement patterns.

Adult↗
PubMed1998

Echo-planar perfusion MR of moyamoya disease.

PURPOSE: Our goal was to assess the value of perfusion MR imaging by using a single-shot echo-planar technique to evaluate the hemodynamics of moyamoya disease. METHODS: We performed echo-planar perfusion studies in 19 patients with a 1.5-T unit, using a free-induction-decay echo-planar sequence for 14 examinations and a turbo-gradient-spin-echo echo-planar sequence for five examinations. After a bolus injection of contrast material, 30 consecutive scans were done in 10 sections every 2 seconds. The data were analyzed to yield time-intensity curves for a region of interest set in the territory of the bilateral middle and/or anterior cerebral arteries in all examinations and to produce semiquantitative flow maps of each section, representing the signal decrease due to passage of contrast material in 17 examinations. The semiquantitative flow maps were compared with single-photon emission CT (SPECT) findings in 11 cases. RESULTS: We detected differences between the cerebral hemispheres and/or focal perfusion abnormalities by the time-intensity curves and semiquantitative flow maps in 15 of the 19 examinations and in 11 of the 17 examinations, respectively. Results of one or both these examinations corresponded with the SPECT findings in nine of the 11 examinations. CONCLUSION: Our results indicate that single-shot echo-planar perfusion MR imaging can sensitively depict hemodynamic abnormalities in moyamoya disease.

Adolescent↗
PubMed1998

Diagnosis of anomalous pancreaticobiliary junction: value of magnetic resonance cholangiopancreatography.

BACKGROUND: Anomalous pancreaticobiliary junction (a long common channel), with or without congenital choledochal cyst, is frequently associated with biliary tract carcinoma. We assessed the diagnostic value of magnetic resonance cholangiopancreatography (MRCP) for patients with anomalous pancreaticobiliary junction (PBJ). METHODS: In 159 adult patients with pancreatobiliary disease, breath-hold (1 to 18 seconds) MRCP was performed according to a half-Fourier acquisition single-shot turbo spin-echo sequence. In all patients the length of the common channel demonstrated by MRCP was compared with that demonstrated by endoscopic retrograde cholangiopancreatography. In 11 patients with anomalous PBJ (the common channel > or = 15 mm on endoscopic retrograde cholangiopancreatography), the diagnostic accuracy of MRCP for associated biliary diseases was evaluated. RESULTS: No complications were encountered in performing MRCP. On MRCP, the length of the common channel was calculated to be 15 mm or longer in nine (82%) of 11 patients with anomalous PBJ. In patients with normal PBJ, MRCP identified PBJ with the channel measuring 0 mm in length. MRCP allowed detailed visualization of congenital choledochal cyst (all seven patients) but failed to depict carcinoma (one patient) and mucosal hyperplasia (five patients) of the gallbladder. CONCLUSIONS: MRCP is a noninvasive and accurate imaging method for diagnosing anomalous PBJ and congenital choledochal cyst.

Adolescent↗
PubMed1998

[The utilities and outlooks of MR cholangiography (MRCP) as a non contrast and noninvasive technique].

Endoscopic retrograde cholangiopancreatography (ERCP) is regarded as the diagnostic procedure of decision for abnormalities of the biliary and pancreatic ducts. However, ERCP is unsuccessful in 3-10% cases and is also associated with a 1-5% risk of producer-induced pancreatitis and other complications. MR cholangiography (MRCP) has recently developed as a noninvasive examination for evaluation of pancreaticobiliary diseases. Heavily T2-weighted fat-suppressed sequences are used to obtain these images. On MRCP, static fluid, such as bile or pancreatic juice represents hyperintense without injection of contrast medium. Therefore, MRCP could be examined in almost all patients including as infant or the patients of post reconstruction of gastrointestinal tract without any complication. In this paper, I described the several utilities and outlooks of MRCP as a noninvasive technique through the representative clinical applications.

Adult↗
PubMed1998

[Breath-hold MR cholangiopancreatography with 2D and 3D-FASE sequence at 0.5 tesla: evaluation based on measurements of signal intensity ratio and contrast-to-noise ratio].

Single-slice 2D-FASE (more than 2 cm) and 3D-FASE images proved to be reliable techniques by which to create high-resolution MRCP images at 0.5 T. In particular, 3D-FASE sequence can provided MIP and its thin source images with sufficient SIR and CNR of the images, which are useful to evaluate detailed structures. Using 3D-FASE sequence, even the non-dilated pancreatobiliary system can frequently be demonstrated because each source image retains satisfactory SIR and CNR of the images due to 3D acquisition and is not affected by motion artifacts of any kind. The most important problem for 3D-FASE sequence is that view-to view amplitude modulation errors may persist, though gradient moment errors can be reduced because of no actual motion during acquisition, resulting in degraded the MIP images due to the different positions of the source images in a few patients with inconstant respiration.

Biliary Tract↗
PubMed1997

Directed proximal magnetic resonance coronary angiography compared with conventional contrast coronary angiography.

Magnetic resonance coronary angiography in 36 patients with proximal 1-vessel disease within 1 week of contrast coronary angiography was performed and the time required to complete the study was 13.4 +/- 4.2 min 13.2 +/- 8.1 minutes for the right and left coronary arteries, respectively. The sensitivity, specificity, positive and negative predictive values, and accuracy of magnetic resonance coronary angiography were 100% for right cronary artery disease, and 83%, 98%, 94%, 94%, and 94%, respectively, for left coronary artery disease.

Aged↗
PubMed1997

Pancreatic ductal adenocarcinoma: preoperative assessment with helical CT versus dynamic MR imaging.

PURPOSE: To compare helical computed tomography (CT) and dynamic, magnetic resonance (MR) imaging in the evaluation of pancreatic ductal adenocarcinoma. MATERIALS AND METHODS: Dynamic MR images obtained with breath holding, 256 phase- and 512 frequency-encoding steps, 5-mm section thickness, phased-array multicoil, and double-dose gadolinium were available from 21 patients. Dynamic MR images were retrospectively compared with helical CT images in the evaluation of tumor detection, local tumor extension, and vascular involvement. RESULTS: Tumors were detected on dynamic MR images of 19 of 21 (90%) patients and on helical CT scans of 16 (76%) patients. Dynamic MR imaging had equal or better sensitivity, accuracy, and agreement of tumor grade than did helical CT in the comparison of imaging findings and histopathologic findings. Dynamic MR imaging also had equal or better specificity than had helical CT in determination of local tumor extension and vascular involvement, except in the factors of duodenal invasion and portal venous system involvement. However, there was no statistically significant difference among any of these measurements. CONCLUSION: Dynamic MR imaging may be better than helical CT in the preoperative detection and evaluation of local tumor extension and of vascular involvement of pancreatic ductal adenocarcinomas.

Adult↗
PubMed1997

Perfusion-weighted MR imaging in the upper abdomen: preliminary clinical experience in 61 patients.

OBJECTIVE: We quantitatively analyzed the potential usefulness of perfusion-weighted (PW) MR imaging of the upper abdomen performed with a single-shot gradient-recalled echo echoplanar (GRE EP) sequence. SUBJECTS AND METHODS: PW imaging of the upper abdomen with a GRE EP sequence was performed in 61 patients who had suspected liver or pancreatic disease. PW imaging was started at the time of administration of 0.1 mmol/kg of gadopentetate dimeglumine, and images were obtained every 2 sec for 88 sec. Time-intensity curves for the liver, pancreas, spleen, and kidney, and for subgroups of patients with various pathologic conditions, were constructed for quantitative analysis. RESULTS: The signal-intensity changes seen throughout the PW imaging process differed for each abdominal organ and pathologic condition. In the spleen, pancreas, and renal cortex, a transient signal-intensity decrease was seen in the perfusion phase (42%, 39%, and 78%, respectively). In the liver and renal medulla, the maximum signal-intensity decrease occurred in the later phase rather than in the perfusion phase. Signal-intensity recovery in the spleen and pancreas occurred soon after the maximum signal-intensity decrease, whereas such recovery was delayed in the liver and renal cortex. In cirrhotic livers, the signal-intensity change seen throughout the examination was minimal. CONCLUSION: Unlike conventional MR imaging, PW imaging with a GRE EP sequence can provide detailed hemodynamic information about upper abdomen organs and about disorders of these organs because of its excellent temporal resolution and susceptibility to contrast enhancement.

Abdomen↗
PubMed1997

Fast fluid-attenuated inversion-recovery MR of intracranial infections.

PURPOSE: To assess the usefulness of fast fluid-attenuated inversion-recovery (FLAIR) MR sequences in the diagnosis of intracranial infectious diseases. METHODS: We compared fast FLAIR images with conventional spin-echo images (T1- and T2-weighted) obtained in 20 patients with infectious diseases (six with encephalitis, five with brain abscesses, three with meningitis, two with meningoencephalitis, two with Creutzfeldt-Jakob disease, one with epidural empyema, and one with cysticercosis). Two neuroradiologists independently reviewed the FLAIR images and compared them with the conventional spin-echo images, obtaining agreement in all patients. RESULTS: FLAIR images of diagnostic quality were obtained in 18 patients. In two patients, FLAIR images were degraded by motion. Lesions in the patients with encephalitis and meningoencephalitis were better delineated on FLAIR images than on spin-echo images. FLAIR images clearly depicted lesions in the basal ganglia in both patients with Creutzfeldt-Jakob disease. In patients with brain abscess, meningitis, cysticercosis, and epidural empyema, FLAIR images provided no more information than conventional spin-echo images, and the lesions were seen better on postcontrast T1-weighted spin-echo images. CONCLUSION: Fast FLAIR images showed pathologic changes in intracranial infectious diseases better than or as well as conventional T2- and proton density-weighted spin-echo sequences. However, postcontrast T1-weighted spin-echo sequences resulted in better visibility of abscess, meningitis, cysticercosis, and epidural empyema than did FLAIR images.

Adolescent↗