Publications by authors named "Harumi Sakahara"

Significance: The water and lipid content of normal breast tissue showed mammary gland characteristics with less influence from the chest wall using six-wavelength time-domain diffuse optical spectroscopy (TD-DOS) in a reflectance geometry.

Aim: To determine the depth sensitivity of a six-wavelength TD-DOS system and evaluate whether the optical parameters in normal breast tissue can distinguish dense breasts from non-dense breasts.

Approach: Measurements were performed in normal breast tissue of 37 breast cancer patients.

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To evaluate the improvement of radiologist performance in detecting bone metastases at follow up low-dose computed tomography (CT) by using a temporal subtraction (TS) technique based on an advanced nonrigid image registration algorithm.Twelve patients with bone metastases (males, 5; females, 7; mean age, 64.8 ± 7.

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Purpose: 2D cine phase contrast (PC)-MRI is a standard velocimetry for the superior mesenteric artery (SMA); however, the optimal localization of the measurement plane has never been fully discussed previously. The purpose of this Institutional Review Board approved prospective and single arm study is to test whether flow velocimetry of the SMA with combined use of 2D cine PC-MRI and meal challenge is dependent on the localizations of the measurement planes and to seek optimal section for velocimetry.

Methods: Seven healthy volunteers underwent cardiac phase resolved ECG gated 2D cine PC-MRI pre- and 30 min post-meal challenge at three measurement planes: proximal, curved mid section and distal straight section of the SMA at 3T.

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Purpose: Evaluate in vivo hemodynamic and morphological biomarkers of intracranial aneurysms, using magnetic resonance fluid dynamics (MRFD) and MR-based patient specific computational fluid dynamics (CFD) in order to assess the risk of rupture.

Methods: Forty-eight intracranial aneurysms (10 ruptured, 38 unruptured) were scrutinized for six morphological and 10 hemodynamic biomarkers. Morphological biomarkers were calculated based on 3D time-of-flight magnetic resonance angiography (3D TOF MRA) in MRFD analysis.

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We measured total hemoglobin concentrations in breast tumors by near-infrared time-resolved spectroscopy. Muscles interfere with measurement when the probe is close to the chest wall. Since the target area of measurement depends on the distance between the light source and probe detector, we inferred that this issue could be solved by reducing the source-detector distance.

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We introduced a method for producing solid phantoms with various water-to-lipid ratios that can simulate the absorption, and to some extent the scattering characteristics of human breast tissue. We also achieved phantom stability for a minimum of one month by solidifying the emulsion phantoms. The characteristics of the phantoms were evaluated using the six-wavelength time-domain diffuse optical spectroscopy (TD-DOS) system we developed to measure water and lipid contents and hemoglobin concentration.

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Objective:: Mesenchymal chondrosarcoma (MCS) of the orbit is a rare and aggressive form of chondrosarcoma. The purpose of this study was to retrospectively identify the imaging features of mesenchymal chondrosarcoma of the orbit.

Methods:: This study included five patients with histologically confirmed MCS of the orbit who had undergone either CT, MRI, or both.

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The purpose of this study was to evaluate the effects of the thickness and depth of tumors on hemoglobin measurements in breast cancer by optical spectroscopy and to demonstrate tissue oxygen saturation (SO2) and reduced scattering coefficient (μs') in breast tissue and breast cancer in relation to the skin-to-chest wall distance. We examined 53 tumors from 44 patients. Total hemoglobin concentration (tHb), SO2, and μs' were measured by time-resolved spectroscopy (TRS).

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Mesenchymal chondrosarcoma of the orbit is an extremely rare and aggressive tumor. We report image findings of F-fluorodeoxyglucose (FDG) positron emission/computed tomography (PET/CT) in 2 cases, one primary case and one recurrent case. The F-FDG PET/CT images revealed high uptake with an SUVmax of 6.

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Purpose: To assess the performance of four-dimensional phase-contrast vastly undersampled isotropic projection reconstruction (4D PC-VIPR) at 3.0T in depicting intrarenal arteries compared with computed tomography angiography (CTA), and its correlation with arterial flowmetry in comparison with Doppler ultrasonography (DUS).

Materials And Methods: In our prospective single-arm study, subjects were 25 patients who underwent renal transplant-related surgery at our hospital between July 2011 and June 2015.

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Background: Optical imaging and spectroscopy using near-infrared light have great potential in the assessment of tumor vasculature. We previously measured hemoglobin concentrations in breast cancer using a near-infrared time-resolved spectroscopy system. The purpose of the present study was to evaluate the effect of the chest wall on the measurement of hemoglobin concentrations in normal breast tissue and cancer.

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Background: Recently, time-resolved 3D phase contrast magnetic resonance imaging (4D-flow) allows flow dynamics in patients with pulmonary arterial hypertension to be measured. Abnormal flow dynamics, such as vortex blood flow pattern in the pulmonary artery (PA), may reflect progression of pulmonary arterial hypertension (PAH). Some reports suggested that abnormal blood flow parameters including wall shear stress (WSS) could be markers of PAH.

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Background: An endoleak is a common complication of endovascular abdominal aortic aneurysm repair (EVAR), and it can be associated with aneurysmal growth. This pilot study used 4-dimensional flow-sensitive magnetic resonance imaging (4D-flow) to assess the hemodynamics of different types of endoleaks (I-IV).

Methods and results: Magnetic resonance angiography, 4D-flow, and computed tomography angiography (CTA) were performed in 31 patients after nitinol-based stent-graft deployment.

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Purpose: To examine how left ventricular (LV) volume and function affect flow dynamics by analyzing 3D intra-LV vortex features using 4D-Flow.

Materials And Methods: Twenty-one patients with preserved (LVEF > 60%) and 14 with impaired LV function (LVEF < 40%) underwent 4D-Flow (at 3T).

Results: In patients with preserved LV function, the intra-LV vortices developed in both the early and late diastolic phases.

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Unlabelled: Diffuse optical spectroscopic imaging (DOSI) is used as an indicator of tumor blood volume quantified by tissue hemoglobin concentrations. We aimed to determine whether early changes in tumor total hemoglobin (tHb) concentration can predict a pathologic complete response (pCR) to neoadjuvant chemotherapy in patients with operable breast cancer, and we compared the predictive value of pCR between DOSI and (18)F-FDG PET combined with CT.

Methods: Of the 100 patients enrolled, 84 patients were prospectively evaluated for primary objective analysis.

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Purpose: To measure T1 and T2 values of hepatic postmortem magnetic resonance (PMMR) imaging.

Materials And Methods: We performed hepatic PMMR imaging of 22 deceased adults (16 men, 6 women; mean age, 56.3 years) whose deaths were for reasons other than liver injury or disease at a mean of 27.

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Cryosurgery is a minimally invasive treatment for certain types of cancers. Argon-based cryosurgical devices are available at present, however a large compressed gas cylinder with the pressure of 300 atmospheres is needed. To overcome these drawbacks, we developed a new cryosurgical probe measuring about 50 cm in length with separate lumens inside for liquid and gaseous ethylene to be used as a thermosiphon and liquid nitrogen-cooled aluminum thermal storage blocks.

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Purpose: 1) To assess the usefulness of an elastic belt bracing the upper abdomen for reducing the miscalculated areas of the pancreas on 3.0T magnetic resonance elastography (MRE); 2) to test whether MRE can detect difference of stiffness between normal pancreas and the focal pancreatic diseases.

Materials And Methods: Using an initial eight normal volunteers, miscalculated areas were compared between MRE with the elastic belt and without the belt on 3.

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We performed 3-dimensional cine phase-contrast magnetic resonance-based computational fluid dynamics for a basilar artery that developed a sidewall aneurysm over a 25-month period. There was an area with high gradient oscillatory number in the location of the future aneurysm ostium and an area with high wall shear stress (WSS) and high spatial WSS gradient at the distal edge of the future aneurysm. These could be biomarkers for development of intracranial aneurysms.

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The common sites of breast cancer metastases include bones, lung, brain, and liver. Renal metastasis from the breast is rare. We report a case of breast cancer metastatic to the kidney with extension into the renal vein.

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Pseudo-continuous arterial spin labeling (PCASL) can measure tumor blood flow (TBF) reliably. We investigated meningioma TBF using PCASL and assessed for any correlation with histopathological microvascular density (MVD) and the World Health Organization (WHO) classification. Conventional MRI with contrast T1-weighted images and PCASL were acquired with a 3 T scanner before surgery in 25 consecutive patients with meningiomas.

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Background: The intra-left atrial (LA) blood flow from pulmonary veins (PVs) to the left ventricle (LV) changes under various conditions and might affect global cardiac function. By using phase-resolved 3-dimensional cine phase contrast magnetic resonance imaging (4D-Flow), the intra-LA vortex formation was visualized and the factors affecting the intra-LA flow dynamics were examined.

Methods And Results: Thirty-two patients with or without organic heart diseases underwent 4D-Flow and transthoracic echocardiography.

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Decreased absolute tumor blood flow (TBF) measured by arterial spin labeling perfusion imaging (ASL-PI) on 3-tesla magnetic resonance imaging demonstrated the reduced size and growth hormone (GH) secretion of a large GH-producing pituitary adenoma in a 32-year-old man in response to octreotide therapy. The study shows the usefulness of ASL-PI in providing a biomarker of the antiangiogenic effect of octreotide.

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Objective: The prognosis of apical hypertrophic cardiomyopathy (APH) has been benign, but apical myocardial injury has prognostic importance. We studied functional, morphological and electrocardiographical abnormalities in patients with APH and with apical aneurysm and sought to find parameters that relate to apical myocardial injury.

Study Design: a multicentre trans-sectional study.

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Background: New imaging modalities to assess the efficacy of drugs that have molecular targets remain under development. Here, we describe for the first time the use of time-resolved three-dimensional phase-contrast magnetic resonance imaging to monitor changes in blood supply to a tumor during sunitinib treatment in a patient with localized renal cell carcinoma.

Case Presentation: A 43-year-old Japanese woman with a tumor-bearing but functional single kidney presented at our hospital in July 2012.

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