Keiji Matsunaga

Kitasato University, Edo, Tōkyō, Japan

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Publications (19)33.03 Total impact

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    ABSTRACT: To evaluate the feasibility of transarterial therapy (transcatheter arterial chemoembolization and transcatheter arterial infusion) for patients with hepatocellular carcinoma and chronic kidney disease (CKD).
    Journal of vascular and interventional radiology: JVIR 10/2014; · 1.81 Impact Factor
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    ABSTRACT: We present two cases of acquired uterine arterial venous malformation (AVM) which was diagnosed because of massive genital bleeding successfully treated with transcatheter arterial embolization (TAE), using N-butyl-2-cyanoacrylate (NBCA) under balloon occlusion. Balloon occlusion at the uterine artery was performed in both patients for diffuse distribution of NBCA in multiple feeding branches, as well as to the pseudoaneurysm, and for the prevention of NBCA reflux. In one of our patients, balloon occlusion of the draining vein was simultaneously performed to prevent NBCA migration through accompanying high-flow arteriovenous fistula (AVF). Doppler ultrasound at 6 months of both patients documented persistent complete occlusion of AVM. Complete and safe obliteration of acquired uterine AVM was accomplished using NBCA as embolic agent, under balloon occlusion at the communicating vessels of acquired uterine AVM.
    Acta radiologica short reports. 09/2014; 3(8):2047981614545910.
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    ABSTRACT: To optimize the navigator-gating technique for the acquisition of high-quality three-dimensional spoiled gradient-recalled echo (3D SPGR) images of the liver during free breathing.
    Magnetic resonance imaging. 06/2014;
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    ABSTRACT: Septal penetration causes underestimation of the heart-to-mediastinum (H/M) ratio in cardiac (123)I-metaiodobenzylguanidine (MIBG) imaging with a low-energy high-resolution (LEHR) collimator. We aimed to improve the method of estimating the H/M ratios using the LEHR collimator. 4 hours after (123)I-MIBG injection, 40 patients were imaged successively with the medium-energy (ME) and LEHR collimators using gamma cameras having 3/8-inch crystals. Severe underestimation of the H/M ratios was observed with the LEHR collimator when compared to the ME collimator. Narrowing the energy window width did not reduce the underestimation. Application of (123)I-dual-window (IDW) correction using a narrow or wide subwindow reduced the underestimation substantially but not entirely. The H/M ratios estimated from the LEHR images with or without IDW correction were corrected based on their correlations with the ratios estimated from the ME images. This empiric correction removed systematic underestimation, and residual errors were reduced when the H/M ratios after IDW correction were converted using the empiric equation. The conversion equation was successfully applied to the correction of the H/M ratios determined in another 40 patients using a 5/8-inch crystal. In estimating the H/M ratios using an LEHR collimator, empiric correction combined with IDW correction improves concordance with ME-based values in comparison with empiric correction alone.
    Journal of Nuclear Cardiology 04/2014; · 2.85 Impact Factor
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    ABSTRACT: OBJECTIVE: We evaluated intra- and interoperator reproducibilities in calculating the conventional indices HH15 and LHL15 from (99m)Tc-diethylenetriamine pentaacetic acid galactosyl human serum albumin ((99m)Tc-GSA) scintigraphy, and proposed new, simple methods for the calculation of quantitative indices. METHODS: The results of (99m)Tc-GSA scintigraphy in 33 patients were retrospectively analyzed. Heart and liver ROIs were drawn manually to cover cardiac blood pool and entire liver, respectively, and HH15 and LHL15 were calculated. In addition, square regions of interest (ROIs) of fixed sizes were placed at the highest activity in blood pool and the liver. Using the square heart ROI, sHH15, an equivalent of HH15, was computed. Fractional liver uptake at 15 min (FLU15) was calculated using the square heart and liver ROIs. Intra- and interoperator reproducibilities, as well as correlation with Indocyanine green retention rate at 15 min (ICG R15), were assessed for these four indices by linear regression analysis. RESULTS: Substantial intra- and interoperator variabilities were found for HH15 and LHL15. The correlation coefficients for intra- and interoperator comparisons were 0.884 and 0.869 for HH15, respectively, and 0.919 and 0.917 for LHL15, respectively. The use of square ROIs instead of hand-drawn ROIs improved reproducibility. The correlation coefficients for intra- and interoperator comparisons were 0.988 and 0.973 for sHH15, respectively, and 0.989 and 0.975 for FLU15, respectively. Correlation with ICG R15 was better for sHH15 (r = 0.619) and FLU15 (r = -0.656) than for HH15 (r = 0.439) and LHL15 (r = -0.490). CONCLUSIONS: HH15 and LHL15 showed substantial intra- and interoperator variabilities, and the use of square ROIs are indicated to provide better reproducibility.
    Annals of Nuclear Medicine 04/2013; · 1.41 Impact Factor
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    ABSTRACT: Septal penetration of high-energy photons affects quantitative results in imaging of (123)I-labeled tracers. We investigated acquisition protocols (collimator choice and energy window setting) and correction methods for estimating the heart-to-mediastinum (H/M) ratio in cardiac (123)I-metaiodobenzylguanidine (MIBG) imaging. METHODS: Four hours after (123)I-MIBG injection, 40 patients successively underwent planar anterior chest imaging with the medium-energy (ME) (ME method) and low-energy high-resolution (LEHR) (LEHR method) collimators. A 20% energy window was used for both collimators. Another 40 patients were imaged successively with the ME collimator and a 20% window (ME method), the low-medium-energy (LME) collimator and a 20% window (LME20 method), and the LME collimator and a 15% window (LME15 method). The H/M ratios obtained by the LEHR, LME20, and LME15 methods were corrected using their correlations with the H/M ratio obtained by the ME method (empiric correction). The (123)I-dual-window (IDW) correction was also applied to remove the influence of high-energy photons. RESULTS: Without correction, severe underestimation of the H/M ratio was shown for the LEHR method using the ME method as a standard, and this underestimation increased with increasing H/M ratios. Underestimation substantially decreased using the LME20 method and further using the LME15 method. Empiric correction reduced the error in the H/M ratio by the LEHR method, but the error was still evident. After empiric correction, the H/M ratios with the LME collimator were comparable to those with the ME collimator. The IDW correction only partially reduced underestimation by the LEHR method and caused a small overestimation for the LME15 method. CONCLUSION: The use of an LME collimator appears to be acceptable for cardiac (123)I-MIBG imaging as an alternative to an ME collimator, and the application of a 15% energy window is recommended when an LME collimator is used. Empiric correction is also expected to improve exchangeability between H/M ratios calculated with ME and LME collimators. Neither the use of an LEHR collimator nor the use of IDW correction is recommended.
    Journal of Nuclear Medicine 03/2013; · 5.77 Impact Factor
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    ABSTRACT: To evaluate the feasibility and usefulness of imipenem/cilastatin sodium (IPM/CS) as an embolic agent for intestinal bleeding from neoplasms. Seven patients who underwent 11 transarterial embolisations (TAEs) using IPM/CS as an embolic material for duodenal or small/large intestinal tumour bleeding from January 2004 to December 2011 were retrospectively evaluated. A mixture of IPM/CS and contrast medium was introduced through the microcatheter positioned at the feeding artery to the tumour until extravasation disappeared or stasis of blood flow to the tumour staining was observed. Haemostasis was obtained in all patients. Therefore, the technical success rate was 100%. Rebleeding was observed in four patients. All of them underwent repeat TAE using IPM/CS, and haemostasis was obtained successfully. No complication was identified following laboratory and clinical examinations. No haemorrhagic death occurred. Haemorrhagic parameters, including blood haemoglobin and the amount of blood transfusion, improved after TAE. The safety, feasibility, and effectiveness of TAE using IPM/CS as an embolic material for intestinal bleeding from neoplasms were suggested by this study. The mild embolic effect of IPM/CS may be adequate for oozing from tumours. Although rebleeding may occur after embolotherapy using IPM/CS, repeat embolisation is effective as treatment for rebleeding.
    SpringerPlus 01/2013; 2:344.
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    ABSTRACT: PURPOSE: To prospectively compare the navigator-echo triggering technique (navigator technique) and the conventional respiratory triggering technique using bellows (bellows technique) for free-breathing three-dimensional (3D) magnetic resonance cholangiopancreatography (MRCP) under clinical conditions. MATERIALS AND METHODS: Forty patients referred for evaluation of biliary or pancreatic diseases underwent 3D MRCP examination using both navigator and bellows techniques. Two independent radiologists visually evaluated the image quality of 12 segments of the pancreaticobiliary tree in a blinded manner. In addition, the clarity of the lesion was compared between the two techniques in a side-by-side manner. RESULT: MRCP images were successfully acquired using both techniques in all patients. No significant difference in acquisition time was found between the two techniques. The image quality was significantly better using the navigator technique than using the bellows technique for the following seven segments: the head, body, and tail of the pancreatic duct; right hepatic duct; anterior and posterior segments of the right hepatic duct; and cystic duct. The other segments (common hepatic and bile duct, left hepatic duct, medial and lateral segments of left hepatic duct, gallbladder) showed no significant difference. The clarity of lesion depiction was significantly better using the navigator technique than using the bellows technique. CONCLUSION: Respiratory-triggered 3D MRCP using the navigator technique was shown to be feasible in routine clinical practice. The navigator technique improved the image quality of free-breathing 3D MRCP compared with the bellows technique. The clarity of lesion visualization was also better using the navigator technique than using the bellows technique.
    Magnetic Resonance Imaging 10/2012; · 2.06 Impact Factor
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    ABSTRACT: PURPOSE: To assess the effect of motion artifact reduction on the diffusion-weighted magnetic resonance imaging (DWI-MRI) of the liver, we compared velocity-compensated DWI (VC-DWI) and VC-DWI combined with tetrahedral gradients (t-VC-DWI) to conventional DWI (c-DWI) in the assessment of apparent diffusion coefficients (ADCs) of the liver. MATERIALS AND METHODS: In 12 healthy volunteers, the liver was scanned with c-DWI, VC-DWI, and t-VC-DWI sequences. The signal-to-noise ratio (SNR) and ADC of the liver parenchyma were measured and compared among sequences. RESULTS: The image quality was visually better for t-VC-DWI than for the others. The SNR for t-VC-DWI was significantly higher than that for VC-DWI (P < 0.05) and comparable to that for c-DWI. ADCs in both hepatic lobes were significantly lower for t-VC-DWI than for c-DWI (P < 0.01). ADC in the left lobe was significantly lower for VC-DWI than for c-DWI (P < 0.01). Although ADC in the left lobe was significantly higher for c-DWI (P < 0.01), no significant differences in ADCs were found between the right and left lobes for VC-DWI and t-VC-DWI. CONCLUSION: The use of a t-VC-DWI sequence enables us to correct ADCs of the liver for artificial elevation due to cardiac motion, with preserved SNR. J. Magn. Reson. Imaging 2012;. © 2012 Wiley Periodicals, Inc.
    Journal of Magnetic Resonance Imaging 09/2012; · 2.57 Impact Factor
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    ABSTRACT: Gastric uptake of (67)Ga may be observed in patients with no obvious gastric lesions, as well as those with gastric malignancy. The aim of this study was to investigate whether the use of an effervescent agent aids in evaluating gastric (67)Ga uptake. Twenty patients having or suspected of having gastric uptake on whole-body (67)Ga scintigrams were studied. Anterior abdominal images were obtained at baseline and after the oral intake of the effervescent agent (gas contrast image). The presence or absence of malignant gastric uptake was judged visually using the baseline image or gas contrast image. The judgment was compared with the clinical diagnosis, and the clinical usefulness of the gas contrast technique was assessed. In all patients, successful distension of the stomach was indicated in the gas contrast image. Clinical assessment showed gastric lesions in six patients (gastric involvement of lymphoma in 3, primary gastric lymphoma in 2, and adenocarcinoma in 1). The gas contrast image yielded accurate judgments of malignant gastric uptake in all patients except one with adenocarcinoma. Imaging after gastric distension induced by the oral effervescent agent contributed to excluding malignant gastric uptake in eight patients and demonstrating malignant gastric uptake in four patients. Benign gastric uptake may complicate the assessment of gastric lesions in (67)Ga scintigraphy. Additional spot imaging after oral intake of an effervescent agent can aid in evaluating malignant gastric lesions through gastric distension.
    Annals of Nuclear Medicine 11/2011; 26(2):192-6. · 1.41 Impact Factor
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    ABSTRACT: PURPOSE Myocarditis or cardiac sarcoidosis are well known as major causes of non-ischemic heart failure. They are characterized microscopical or gross cell infiltration into the myocardium. Cardiac MRI is non-invasive method, and it can offer to make a diagnosis of infiltrative foci in organs. The purpose of this study was to compare MRI with and the pathological findings of the sample of myocardium. METHOD AND MATERIALS Serial thirty-six congestive heart failure patients (male, 23; female, 13) without ischemic heart desease, severe valve disease or congenital disease were enrolled in this study. Myocardial biopsy was done from epicardium in the left ventricle. The sample was stained with H.E., and evaluated infiltration foci microscopically. The specimens were classified into 3 categories; none, mild, or severe infiltration foci. MRI protocol including fast spin echo T2 weighed inverted recovery images (T2WI), and gadolinium delayed enhanced (DE) images were undergone. Positive findings of T2WI was defined as transmural high intensity in the left ventricle wall. RESULTS Six cases had severe infiltration foci in the myocardium microscopically. Severe cell infiltration foci in the cases were all detected by T2WI as transmural high intensity lesions. DE could detect them in five cases. Moreover, clear discrepancy in each 6 case was seen between T2WI and DE. The discrepancy was assumed that T2WI indicated edema in cell infiltration foci, while DE indicated myocardial damages or fibrosis in the left ventricle. CONCLUSION T2WI in cardiac MRI was a useful non-invasive method as a marker of infiltration in non-ischemic heart failure. CLINICAL RELEVANCE/APPLICATION MR T2 Weighed Imaging can detect the correct infiltration in hearts with myocarditis, and that will make treatment appropriate.
    Radiological Society of North America 2008 Scientific Assembly and Annual Meeting; 12/2008
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    ABSTRACT: For many years, patients with recurrent or distant metastatic cancer have been considered to be at the last stage of their lives because it was considered that the cancer had spread throughout the whole body. However, the development of methods for the early detection of recurrence or distant metastases allows the detection of limited site recurrence or single organ metastases, called oligometastases or oligo-recurrence. Additional local treatment for oligometastatic or oligo-recurrent lesions such as radiation therapy could be efficacious. The purpose of the current study was to evaluate radiation therapy for solitary osseous metastasis of breast cancer in terms of oligometastasis and oligo-recurrence. One hundred and thirteen breast cancer patients were treated with radiation therapy for osseous metastases at Kitasato University Hospital, Japan between January 1998 and March 2003. Out of them, seven patients had solitary osseous metastases with primary and other sites controlled. These patients were registered in the current study, three had lumber spine metastases, three pelvic and one thoracic spine. The median time between the initial treatment of the primary lesions and diagnosis of the osseous metastases was 44 months (range: 10-95 months). The median total radiation dose was 46 Gy (30-50 Gy; BED: biological effective dose, 39-60 Gy10). The median follow-up time was 40 months (range: 11-80 months). All the patients were alive at the last follow-up. Only one patient relapsed in terms of pain from the osseous metastasis. This patient was treated with 30 Gy (BED 39 Gy10) irradiation, the lowest total dose among the seven patients. Radiation therapy for solitary osseous metastasis might be efficacious and moreover, high dose could be useful for long-term pain relief of osseous metastasis.
    Anticancer research 01/2008; 28(6B):3929-31. · 1.71 Impact Factor
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    ABSTRACT: Locally advanced uterine cervical carcinoma (LAUCC) treated with chemoradiotherapy is considered to be the standard treatment regimen. However, no evidence of its efficacy and safety has been obtained from the Japanese population. Furthermore, the total dose of Japanese radiation therapy protocol is less than that of the USA which indicated that chemoradiotherapy for LAUCC is better than radiation therapy alone by phase III clinical trials. Thus, the current phase II study was designed to evaluate chemoradiotherapy with a lower radiation dose for LAUCC using weekly nedaplatin effectively and safely in the Japanese population. Nedaplatin is a platinum drug and no hydration is required to infuse patients because it is less toxic on renal function. If this phase II trial is successful, chemoradiotherapy for LAUCC in out-patient clinics could be possible. Patients registered in the current study were found to have LAUCC based on the following criteria i) pathologically proven squamous cell carcinoma or adenocarcinoma, ii) FIGO clinical Stage Ib, IIa, IIb with bulky tumor (diameter > 40 mm assessed by pelvic magnetic resonance imaging) or pelvic lymph node swelling (diameter > 10 mm assessed by pelvic computed tomography); iii) FIGO clinical Stage IIIa, IIIb and IVa with no paraaortic lymph node swelling (diameter > 10 mm) observed by abdominal computed tomography; iv) age: 20-75 years; v) performance status: 0-2. The treatment protocol was as follows: Radiation therapy in a combination of external beam radiation therapy (total dose: 50 Gy-52 Gy/25-27 fractions with central shielding after 30-32 Gy) with high-dose rate intracavitary irradiation (24-30 Gy/4-6 fractions to point A). Chemotherapy applied in the current study was weekly nedaplatin infused intravenously (30 mg/mm2/time, once a week, total 150 mg/mm2/5 weeks). Sample size in the current study was 45 LAUCC patients recruited for three years at a single institution. This protocol was permitted by the ethics committee of Kitasato University Hospital. Ten patients were registered in this study between June 2005 and March 2006. The median age was 57.5 years (range 36-73). PS0 was five and PS1 was five. As for clinical stage, nine were IIIb and only one was IIb. Nine patients were proven to have squamous cell carcinoma and one adenocarcinoma. The median maximum tumor diameter was 62.5 mm (range 30-100 mm). As for initial response, eight had CR and two had PR (100% response rate). As for hematological acute morbidity, three were grade 2, six were grade 3, and one was grade 4. This initial analysis of the phase II study confirmed that concurrent chemoradiotherapy using nedaplatin is safe and efficacious, thus we decided to undergo further studies.
    European journal of gynaecological oncology 01/2008; 29(3):222-4. · 0.58 Impact Factor
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    ABSTRACT: Intraperitoneal bleeding from ruptured ectopic varices is a rare and fatal complication in patients with portal hypertension. Although laparotomy with high mortality is performed, it is difficult to detect correct bleeding site and save the patient. This is probably the first case report of rupture from left gastric vein revealed by transjugular intrahepatic portosystemic shunt (TIPS). We propose the use of TIPS for diagnosing and treating intraperitoneal bleeding from ectopic varices.
    Abdominal Imaging 01/2008; 33(3):324-7. · 1.91 Impact Factor
  • American Journal of Roentgenology 06/2006; 186(5 Suppl):S241-3. · 2.90 Impact Factor
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    ABSTRACT: The purpose of this study was to investigate the utility of diffusion-weighted imaging (DWI) and the apparent diffusion coefficient (ADC) value in differentiating benign and malignant breast lesions and evaluating the detection accuracy of the cancer extension. We used DWI to obtain images of 191 benign and malignant lesions (24 benign, 167 malignant) before surgical excision. The ADC values of the benign and malignant lesions were compared, as were the values of noninvasive ductal carcinoma (NIDC) and invasive ductal carcinoma (IDC). We also evaluated the ADC map, which represents the distribution of ADC values, and compared it with the cancer extension. The mean ADC value of each type of lesion was as follows: malignant lesions, 1.22+/-0.31 x 10(-3) mm2/s; benign lesions, 1.67+/-0.54 x 10(-3) mm2/s; normal tissues, 2.09+/-0.27 x 10(-3) mm2/s. The mean ADC value of the malignant lesions was statistically lower than that of the benign lesions and normal breast tissues. The ADC value of IDC was statistically lower than that of NIDC. The sensitivity of the ADC value for malignant lesions with a threshold of less than 1.6 x 10(-3) mm2/s was 95% and the specificity was 46%. A full 75% of all malignant cases exhibited a near precise distribution of low ADC values on ADC maps to describe malignant lesions. The main causes of false negative and underestimation of cancer spread were susceptibility artifact because of bleeding and tumor structure. Major histologic types of false-positive lesions were intraductal papilloma and fibrocystic diseases. Fibrocystic diseases also resulted in overestimation of cancer extension. DWI has the potential in clinical appreciation to detect malignant breast tumors and support the evaluation of tumor extension. However, the benign proliferative change remains to be studied as it mimics the malignant phenomenon on the ADC map.
    Magnetic Resonance in Medical Sciences 02/2005; 4(1):35-42. · 0.75 Impact Factor
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    ABSTRACT: The authors used breast diffusion-weighted imaging (DWI) to diagnose breast cancer and identify cancer extension. Isotropic DWI was performed with EPI. The apparent diffusion coefficient (ADC) value was calculated and displayed on an ADC map. The authors compared between the distribution of low ADC values and pathologic cancer extension. The mean ADC value of breast cancer was 1.12 +/- 0.24 x 10(-3) mm/s, which was lower than that of normal breast tissue. The ADC value for invasive ductal carcinoma was lower than that of noninvasive ductal carcinoma. The sensitivity of the ADC value for breast cancer using a threshold of less than 1.6 x 10(-3) mm/s was 95%. Seventy-five percent of all cases showed precise distribution of low ADC value as cancer extension. The causes of underestimation were susceptibility artifact from bleeding and the limit of spatial resolution. Benign proliferative change showed a low ADC value. The authors conclude that DWI has a potential for clinical appreciation in detecting breast cancer.
    Journal of Computer Assisted Tomography 01/2005; 29(5):644-9. · 1.58 Impact Factor
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    ABSTRACT: We performed CT-angiography twice, first hip joint extension, followed by second flexion. Using vessel analysis software, we placed several points of interest at equal intervals on the center line of the iliac artery, from the bifurcation to the femoral artery inguinal portion, and recorded the their three-dimensional coordinates. We also marked the circumference, which passes by three points that add the respective next point and prior point to each reference point. This curvature (the inverse number of the radius) was utilized as the index that displays crookedness. This method was able to estimate quantitatively the grade of crookedness, and, by comparing an equidistant point from the bifurcation, to show the changes in grade at flexion of the hip joint.
    Nihon Igaku Hoshasen Gakkai zasshi. Nippon acta radiologica 08/2004; 64(5):307-9.
  • Endoscopy 04/1999; 31(3):S22. · 5.74 Impact Factor