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Biomedical subjects

Masatoshi Ishibashi

Publications and source records attributed to Masatoshi Ishibashi.

At least 19 recordsLinked to original sources
PubMed2006

Simvastatin attenuates plaque inflammation: evaluation by fluorodeoxyglucose positron emission tomography.

OBJECTIVES: We investigated whether simvastatin attenuates plaque inflammation by using 18F-fluorodeoxyglucose positron emission tomography (18FDG-PET) co-registered with computerized tomography. BACKGROUND: Inflammation plays a key role in progression and destabilization of atherosclerotic plaque. 18F-fluorodeoxyglucose PET is a promising tool for visualizing inflammation of atherosclerotic plaque. Antiinflammatory action is one of the pleiotropic effects of statins. METHODS: Forty-three consecutive subjects, who underwent 18FDG-PET for cancer screening and had 18FDG uptakes in the thoracic aorta and/or the carotid arteries, were randomized to either statin group receiving simvastatin (n = 21) or diet group receiving dietary management only (n = 22). The maximum standardized uptake values (SUVs) were measured in individual plaques, and were averaged for analysis of the subjectwise results. The responses were assessed after 3-month treatments. RESULTS: Positron emission tomography revealed 117 and 123 18FDG-positive plaques in the statin and diet groups, respectively. Simvastatin, but not diet alone, attenuated plaque (18)FDG uptakes and decreased the SUVs (p < 0.01). Simvastatin reduced low-density lipoprotein cholesterol (LDL-C) by 30% (p < 0.01) and increased high-density lipoprotein cholesterol (HDL-C) by 15% (p < 0.01), whereas LDL-C and HDL-C levels were not changed in the diet group. In the statin group, the decrease in the SUV was well correlated with the HDL-C elevation (p < 0.01) but not with the LDL-C reduction. CONCLUSIONS: 18F-fluorodeoxyglucose PET visualized plaque inflammation and simvastatin attenuated it. The LDL-C-independent effects of simvastatin may participate in the beneficial effect. 18F-fluorodeoxyglucose PET has a potential for visually monitoring plaque inflammation and the therapeutic effectiveness of statins.

Aged↗
PubMed2006

Early gastric cancer and early colon cancer detected simultaneously by PET cancer screening incidentally.

We report a case of early gastric cancer and early colon cancer detected by positron emission tomography (PET) cancer screening. A 64-year-old male patient with an unremarkable past history except for hypertension and cerebrovascular disease underwent 18F-FDG PET for cancer screening. Images revealed increased uptake in the gastric antrum and sigmoid colon. Both areas appeared suspicious for neoplasm on subsequent fluoroscopy and endoscopy, and biopsies were positive for neoplasia at both sites. The gastric lesion was treated by distal gastrectomy and D2 lymphadenectomy and the colon cancer by endoscopic mucosal resection (EMR). Both surgical specimens were positive for cancer.

Colonic Neoplasms↗
PubMed2006

Value of fusing PET plus CT images in hepatocellular carcinoma and combined hepatocellular and cholangiocarcinoma patients with extrahepatic metastases: preliminary findings.

BACKGROUND/AIMS: This study aimed to evaluate the usefulness of (18)F-fluoro-2-deoxy-d-glucose positron emission tomography (PET) and PET plus computed tomography (CT) fusion images for the detection of extrahepatic metastases of hepatocellular carcinoma (HCC) and combined hepatocellular and cholangiocarcinoma (combined HCC/CC). METHODS: Twenty-one patients with HCC and combined HCC/CC were enrolled in the study from December 2004 to February 2005. In all patients, PET and CT of the chest to pelvis region were performed. The sensitivity of PET plus CT fusion images was compared with the sensitivity of PET, CT, and bone scintigraphy. RESULTS: In 14 patients, a total of 58 extrahepatic metastases were diagnosed. The detection rate of PET plus CT fusion images, PET, CT, and bone scintigraphy was 98.2% (57 of 58 metastases), 89.6% (52 of 58 metastases), 91.2% (52 of 57 metastases), and 68.7% (11 of 16 bone metastases), respectively. No extrahepatic metastases were detected in the other seven patients. The detection rate of PET was 10/18 (55.6%) for intrahepatic lesions of HCC and combined HCC/CC. CONCLUSIONS: The fusion of PET plus CT images is useful in detecting extrahepatic metastases in HCC and combined HCC/CC patients.

Adult↗
PubMed2005

[Research on time-course differential imaging by bone scintigraphy].

The temporal image subtraction technique was applied to bone scintigraphy, using Photoshop (commercially available image processing software) and Morpher (public domain warping software). For the temporal subtraction images, 81 subtraction images (19 cases) were prepared by a method used to subtract the previous images from the current ones. Registration of the current and previous images was performed by manual operation using Photoshop, and warping was done using the warping function of Morpher. In addition, difference images prepared after correcting the distributions of radioactive isotopes of the current and previous images using the count of the pelvic region were also examined. Compared with manual operation, alignment of images by warping improved registration and reduced the generation of pseudo-images of subtraction images. The rate of identification of abnormal accumulation-enhanced regions and subjective evaluation by doctors was improved for warping more than for manual operation. Furthermore, abnormal hot regions, which are difficult to find in film images, could be found in three subtraction images. In addition, it was confirmed that abnormal hot regions become more visible in many cases by preparing subtraction images after correcting the count between images using the count of the pelvic region. Thus, it is suggested that the temporal image subtraction technique in bone scintigraphy enables more accurate observation of enhancement of or changes in abnormal hot regions, which will support diagnostic reading. It is considered that enhancement of or changes in abnormal hot regions will be more accurately understood through further detailed discussion in the future.

Bone and Bones↗
PubMed2005

Usefulness of whole PTH assay in patients with renal osteodystrophy--correlation with bone scintigraphy.

OBJECTIVE: Intact parathyroid hormone (PTH) assay has recently been reported to be effective in evaluating both 1-84 PTH (whole PTH) and inactive 7-84 PTH. Inactive 7-84 PTH is considered to be increased in hemodialysis patients and to prevent the effects of 1-84 PTH, and intact PTH is considered to overestimate the PTH activity in these patients. As such, a whole PTH assay has recently been developed. The purpose of this study was to examine the usefulness of a whole PTH assay using the bone to soft tissue (B/ST) ratio on bone scintigraphy. METHOD: Twenty-five hemodialysis patients were included in our study. In all patients, bone scintigraphy and a blood test [whole PTH, intact PTH, alkaline phosphatase (ALP), calcium (Ca), and phosphorus (P)] were performed. Regions of interest (ROIs) were drawn around the cranium, lumbar vertebrae, left femoral neck, and soft tissue of the medial left thigh to obtain the B/ST ratio. RESULTS: The B/ST ratio of the cranium and left femoral neck correlated with whole PTH and intact PTH. In particular, the B/ST ratio of the cranium correlated most significantly with the value of whole PTH. Whole PTH levels correlated with intact PTH levels (r = 0.891, p < 0.0001). CONCLUSION: Our data indicate that a whole PTH assay may be useful in evaluating PTH activity using the B/ST ratio. The B/ST ratio of the cranium may reflect the bone metabolism of hemodialysis patients.

Adult↗
PubMed2005

Evaluation of exercise-induced acute renal failure in renal hypouricemia using Tc-99m DTPA renography.

We present a case of a thirty-eight-year-old man who had exercise-induced acute renal failure (exercise-induced ARF). He experienced oliguria, general fatigue, and vague discomfort in the lower abdomen after he exercised. As he had suffered from hypouricemia before, he was diagnosed as having exercise-induced ARF associated with hypouricemia. Enhanced computed tomography (CT) images showed patchy wedge-shaped contrast enhancement on his bilateral kidneys, consistent with characteristic observations for exercise-induced ARF. Tc-99m diethylene triamine pentaacetic acid (DPTA) renography revealed decreases in both the renal blood flow (RBF) and glomerular filtration rate (GFR), and revealed parenchymal dysfunction of the bilateral kidneys. Renogram revealed a hypofunctional pattern on the bilateral kidneys. CT images and Tc-99m DTPA renography also had improved when the symptoms of exercised-induced ARF indicated improvement. It has been hypothesized that one cause of exercise-induced ARF may be renal vasocontraction. Although CT images are useful in evaluating exercise-induced ARF, Tc-99m DTPA renography can more easily and safely evaluate renal function. We also show that Tc-99m DTPA renography is useful in precisely evaluating the degree of improvement of exercise-induced ARF.

Acute Kidney Injury↗
PubMed2005

Usefulness of bone uptake ratio of bone scintigraphy in hemodialysis patients.

OBJECTIVE: It is important to estimate the bone metabolism in patients with renal osteodystrophy. The methods of estimation must be noninvasive, accurate, and able to measure repeatedly. METHODS: The regions of interest on bone scintigraphy were drawn over the radius in 22 hemodialysis patients (10 males, 12 females). The bone/soft tissue ratio (B/ST ratio) was calculated for all patients. The bone soft tissue ratio of both skull (S) and radius (R) was obtained from the resultant count ratios. We investigated the correlation between intact parathyroid hormone (PTH), alkaline phosphatase (ALP) and the uptake ratios S and R. RESULTS: Intact PTH had a significantly linear correlation with R (r = 0.745, p < 0.0001) and S (r = 0.702, p = 0.0001). ALP also had a significantly linear correlation with R (r = 0.537, p = 0.009) and S (r = 0.772, p < 0.0001). CONCLUSION: The measurement of the bone soft tissue ratio of radius on bone scintigraphy was crucial for estimating renal osteodystrophy.

Adult↗
PubMed2005

Assessment of therapeutic effect in patients with secondary hyperparathyroidism using bone scintigraphy.

OBJECTIVE: The semi-quantitative method of bone scintigraphy [bone to soft tissue (B/ST) ratio] has been used in diagnosing and evaluating systemic metabolic bone diseases. The aim of this study is to evaluate of the therapeutic effect of secondary hyperparathyroidism (SHP). METHODS: The subjects were ten hemodialysis patients with SHP. Seven patients underwent parathyroidectomy (PTX), and 22-Oxacalcitoriol (derivative of 1,25-dihydroxyvitamin D3) (OCT) was given to three patients. Bone scintigraphy and blood tests [intact parathyroid hormone (PTH), alkaline phosphatase (ALP), calcium (Ca), phosphorus (P), bone alkaline phosphatase (BALP), and deoxypridinoline (DPYD)] were performed before and after treatment. Regions of interest were drown around cranium, lumbar vertebrae, femoral neck and soft tissue of left medial thigh to calculate the B/ST ratio. RESULT: The B/ST ratios of cranium, lumbar vertebrae, and femoral neck were reduced significantly after PTX (cranium, p = 0.0079, lumbar vertebrae, p = 0.0282, femoral neck, p = 0.0252). Intact PTH, ALP, Ca, P, BALP and DPYD levels were reduced significantly after PTX (intact PTH, p = 0.003, Ca, p = 0.0005, P, p = 0.0393, ALP, p = 0.0051, DPYD, p = 0.0232, BALP, p = 0.0324). After OCT administration, the B/ST ratio of each bony region showed tendency to diminish, although not significantly. Intact PTH levels were reduced significantly, although ALP, BALP, and DPYD levels were not. Ca and P levels were increased significantly because of the medicinal action of OCT. CONCLUSION: The B/ST ratio of cranium may be non-invasive method and have potential in evaluating the therapeutic effect of SHP.

Adult↗
PubMed2005

Rhabdomyolysis induced by psychotropic drugs.

A 41-year-old man experienced continuous convulsions, unconsciousness, and a high temperature. His laboratory findings revealed an increase in serum creatine phosphokinase, serum myoglobulin, and urinary myoglobulin levels. He had taken many psychotropic drugs as treatment for schizophrenia and was very dehydrated. Because a diagnosis of rhabdomyolysis was suspected, Tc-99m HMDP bone scintigraphy was performed. It showed diffusely increased soft tissue uptake in his shoulder girdles, vertebral area, psoas iliac muscles, and gluteofemoral muscles, leading to a diagnosis of rhabdomyolysis. Bone scintigraphy is useful in making an early diagnosis and evaluating the location and degree of muscle injury in rhabdomyolysis.

Adult↗
PubMed2005

Comparison of histological findings and parathyroid scintigraphy in hemodialysis patients with secondary hyperparathyroid glands.

To determine the usefulness of parathyroid scintigraphy in histological estimation for secondary hyperparathyroidism (2HPT) using Tc-99m sestamibi or Tc-99m tetrofosmin. Tc-99m sestamibi (MIBI) and Tc-99m tetrofosmin (Tetro) parathyroid imaging following double-phase study, magnetic resonance imaging (MRI), and ultrasound were performed on 14 patients with 2HPT. All patients underwent parathyroidectomy. The uptake of two tracers in parathyroid areas was compared with the histopathologic findings. Forty-nine parathyroid glands were surgically explored and histologically proven to be hyperplastic. Of these, 42 were diagnosed with nodular type (N-type) hyperplasia, and 7 with diffuse type (D-type) hyperplasia. MIBI and Tetro parathyroid imagings detected 34 and 35 parathyroid glands, respectively. The sensitivity of MIBI was determined to be 76.2% (32/42) for N-type, and 28.6% (2/7) for D-type. The sensitivity of Tetro was determined to be 78.6% (33/42) for N-type and 28.6% (2/7) for D-type. The sensitivity of both MIBI and Tetro was significantly higher for N-type than for D-type, 76.2% (32/42) vs. 28.6% (2/7) in MIBI, P = 0.022; 78.6% (33/42) vs. 28.6% (2/7) in Tetro, P = 0.015. The sensitivity of MRI was determined to be 76.2% (32/42) for N-type and 42.9% (3/7) for D-type, and the sensitivity of ultrasound was 71.4% (30/42) for N-type and 71.4% (5/7) for D-type. There was no significant difference in the sensitivity of MRI or ultrasound between N-type and D-type. The uptake ratios of MIBI and Tetro were also greater for N-type than for D-type. The detectability of both MIBI and Tetro was greater for N-type than for D-type. Tc-99m MIBI or Tc-99m Tetro parathyroid scintigraphy therefore may be used clinically to distinguish N-type from D-type parathyroid gland hyperplasia.

Adult↗
PubMed2005

Hilar and suprapancreatic cholangiocarcinoma: value of 3D angiography and multiphase fusion images using MDCT.

OBJECTIVE: We evaluated the feasibility of creating 3D and multiphase fusion images of cholangiocarcinoma. The 3D rendering of the biliary tree provide valuable information for planning surgery, including the location of the obstruction and its relationship to the surrounding vessels. CONCLUSION: Our data emphasize that 3D and multiphase fusion images may be an accurate and routinely applicable tool for the diagnosis and therapeutic management of patients with biliary system abnormalities.

Bile Duct Neoplasms↗
PubMed2004

A clinical assessment of the relationship between bone scintigraphy and serum biochemical markers in hemodialysis patients.

BACKGROUND: Renal osteodystrophy is a metabolic bone disease and a common complication of end-stage chronic renal failure and maintenance dialysis treatment. In this study, we examined the correlation between quantifying bone scintigraphy and serum biochemical markers in hemodialysis patients. METHODS: Bone scintigraphy with technetium-99m-hydroxy-methylene-diphosphonate (99mTc-HMDP) was performed on 28 patients on maintenance hemodialysis. Bone scintigraphy was performed using a standard protocol and was quantified by setting regions of interest (ROIs) over selected regions. The bone-to-soft-tissue ratio (B/ST ratio) at each region was calculated in all patients. The B/ST ratios were then compared with serum biochemical markers. RESULTS: The B/ST ratio for the skull correlated well with serum bone-specific alkaline phosphatase (BAP) (r = 0.735, p < 0.001), serum deoxypyridinoline (DPD) (r = 0.806, p < 0.001) and intact parathyroid hormone (intact PTH) (r = 0.701, p < 0.001). The B/ST ratio for the lumbar spine correlated with intact PTH (r = 0.387, p < 0.05) but not with serum BAP or serum DPD. The B/ST ratio for the femoral neck correlated with serum DPD (r = 0.431, p < 0.05) and intact PTH (r = 0.449, p < 0.05) but not with serum BAP. CONCLUSIONS: Our data suggest that quantitative bone scintigraphy is a sensitive and useful method for evaluating bone metabolism in hemodialysis patients. The B/ST ratio for the skull may reflect changes of bone metabolism in hemodialysis patients.

Adult↗
PubMed2003

Technetium-99 m sestamibi imaging in patients with subacute thyroiditis.

To determine if subacute thyroiditis (SAT) is associated with changes in the regional perfusion of the thyroid gland, we performed Tc-99 m sestamibi scans on eleven patients with SAT who had painful goiter and clinical thyrotoxicosis. Eleven patients had Tc-99 m pertechnetate and Tc-99 m sestamibi scintigraphy during the acute stage of SAT. The thyroid uptake ratio of sestamibi was compared with the laboratory data and color Doppler ultrasonography. Tc-99 m pertechnetate scintigraphy in the thyroid was markedly reduced during the acute stage of SAT. Conversely, Tc-99 m sestamibi showed diffuse increased uptake in the thyroid region, suggesting increased perfusion. On the other hand, there was near absence of vascularization in the acute phase and slight increase in the recovery phase by color Doppler ultrasonography. The clearance rate of Tc-99 m sestamibi during the early phase (from 10 min to 1 h) was decreased in the acute stage of SAT. The sestamibi uptake ratio correlated with serum immunosuppressive acidic protein (IAP) in the acute stage of SAT and the sestamibi uptake ratio in the recovery stage of SAT was correlated with serum thyrotropin levels. Tc-99 m sestamibi uptake in the early phase in the acute stage of SAT may reflect the inflammatory process associated with SAT.

Adult↗
PubMed2003

Development of a system which automatically acquires optimal discrete-valued attributes by dividing and grouping continuous-valued attributes to assist clinical decision making in radiotherapy.

The purposes of this study were first to develop a system which statistically tests results of radiotherapy and which automatically acquires an optimal discrete-valued attribute by dividing and grouping continuous-valued attributes, and second to find the optimal range of values such as tumor dose by taking account of the conditions and statistics in ROGAD (Radiation Oncology Greater Area Database), a multi-institutional database in Japan. Our ultimate goal is to assist clinical decision making for every patient. In this research, two algorithms for acquiring a boundary value were developed without detecting false boundaries or accidental errors of acquired boundaries. The resolution of detected discrete-valued attributes and speed of convergence were confirmed to be practical. The optimal range of given tumor dose with the best reaction and with the fewest complications is expected to be clarified.

Algorithms↗
PubMed2002

Study on the usefulness of whole body SPECT coronal image, MIP image in 67Ga scintigraphy.

In this study, we examined the usefulness of whole body coronal images and whole body cine display MIP images (CMIP) upon which image processing was carried out after whole body SPECT in comparison to the usefulness of whole body images (WB/SC) compensated by scattered radiation in tumor/inflammation scintigraphy with 67Ga-citrate (67Ga). Image interpretation was performed for the 120 patients with confirmed diagnoses, and the accuracy of their diagnoses was studied by three nuclear medical physicians and two clinical radiological technologists by means of sensitivity, specificity and ROC analysis. The resultant data show that sensitivity, specificity, accuracy and the area under the ROC curve Az in the WB/SC were approximately 65%, 86%, 74% and 0.724, respectively, whereas sensitivity, specificity, accuracy and Az of the image reading system in which CMIP is combined with whole body coronal images reconstructed by the OS-EM method were approximately 93%, 95%, 94% and 0.860, respectively. Furthermore, coronal images reconstructed by the OS-EM method tended to be superior to those produced by the FBP method in both diagnostic accuracy and ROC analysis. In conclusion, the image reading system in which CMIP is combined with whole body coronal images reconstructed by the OS-EM method was shown to be superior in diagnostic accuracy and ROC analysis. Our data suggest that whole body SPECT is an excellent technique as an alternative to WB/SC.

Adolescent↗
PubMed2002

Study of image findings in rapid eye movement sleep behavioural disorder.

To elucidate the cause of idiopathic rapid eye movement (REM) sleep behavior disorder (RBD), magnetic resonance imaging and single-photon emission computed tomography of the brain were conducted on 20 patients with RBD. Blood flow in the upper portion of both sides of the frontal lobe and pons was significantly lower in patients with RBD than in the normal elderly group. Among the patients with RBD, decreased blood flow in the frontal lobe showed no correlation with the extent of frontal lobe atrophy. Decreased blood flow in the upper portion of the frontal lobe and pons might be associated with the pathogenesis of idiopathic RBD.

Aged↗
PubMed2002

Evolution of virtual CT laparoscopy for preoperative imaging in laparoscopic cholecystectomy.

The purpose of this study was to determine the feasibility of virtual endoscopy, named as "virtual CT laparoscopy", in the hepatobiliary system prior to laparoscopic cholecystectomy. We applied this technique to 28 patients suspected of having biliary disease. These images were compared and analyzed qualitatively based on visualization of the structures critical to operative cholangiography and surgical findings. Twenty-four patients, who underwent laparoscopic cholecystectomy, were evaluated as follows: the common bile duct and the hepatic duct were adequately visualized in 23 (96%) of the 24 patients, the cystic duct in 21 (88%), the gallbladder opacification in 20 (83%), the liver inferior surface in 20 (83%). Four patients had anatomic variations detected virtual CT laparoscopy and were proven by operative cholangiography and surgical findings. We emphasize that our new technique may contribute to the laparoscopy during surgery as the aid of understanding of anatomical structures in these organs.

Adult↗