Publications by authors named "Katsusuke Kyotani"

Introduction: Scarring and pain are postoperative complications in patients after head and neck cancer treatment; however, there is no effective treatment. These complications are affected by local blood flow disorders, and it is well known that the transcutaneous application of carbon dioxide (CO2) improves local blood flow. Previously, we have shown that the transcutaneous application of carbon dioxide causes absorption of CO2 and increase the oxygen (O2) pressure in the treated tissue; it is expected that the application of CO2 may reduce scarring and pain caused by cancer treatment.

View Article and Find Full Text PDF

Atrial fibrosis and inflammation play important roles in perpetuating and initiating atrial fibrillation (AF). Although the fibrotic area can be visualized as a delayed enhancement area on late gadolinium enhancement magnetic resonance imaging (LGE-MRI), atrial inflammation has not yet been visualized on any imaging modality. We describe the protocol for a feasibility study to visualize atrial inflammation on positron emission tomography/MRI (PET/MRI).

View Article and Find Full Text PDF

Background: Atrial inflammation plays an important role in initiating atrial fibrosis, which could perpetuate atrial fibrillation (AF). However, the method of visualization of atrial inflammation has not been established. We sought to investigate whether the intensive atrial inflammation caused by cryoballoon ablation (CBA) could be detected by positron emission tomography/ magnetic resonance imaging (PET/MRI) and whether the atrial inflammation could be associated with consequent fibrosis.

View Article and Find Full Text PDF

Background: A computer simulation model has demonstrated that atrial fibrillation (AF) driver can be attached to heterogeneous fibrosis assessed by late gadolinium enhancement magnetic resonance imaging (LGE-MRI). However, it has not been well elucidated in patients with persistent AF. The aim of this study was to investigate whether radiofrequency (RF) applications in the fragmented LGE area (FLA) could terminate AF or convert it to atrial tachycardia (AT) and improve the rhythm outcome.

View Article and Find Full Text PDF

Cancer cells optimize nutrient utilization to supply energetic and biosynthetic pathways. This metabolic process also includes redox maintenance and epigenetic regulation through nucleic acid and protein methylation, which enhance tumorigenicity and clinical resistance. However, less is known about how cancer cells exhibit metabolic flexibility to sustain cell growth and survival from nutrient starvation.

View Article and Find Full Text PDF

Background: Pulmonary vein isolation (PVI) lesions after cryoballoon ablation (CBA) are characterized as a wider and more continuous than that after conventional radiofrequency catheter ablation (RFCA) without the contact force (CF)-sensing technology. However, the impact on the lesion characteristics of ablation with a CF-sensing catheter has not been well discussed. We sought to assess the lesions using late-gadolinium enhancement magnetic resonance imaging (LGE-MRI) and to compare the differences between the two groups (CB group vs.

View Article and Find Full Text PDF

Background: Few studies have examined the usefulness of intraoperative magnetic resonance spectroscopy (iMRS) for identifying abnormal signals at the resection margin during glioma surgery. The aim of this study was to assess the value of iMRS for detecting proliferative remnants of glioma at the resection margin.

Methods: Fifteen patients with newly diagnosed glioma underwent single-voxel 3-T iMRS concurrently with intraoperative magnetic resonance imaging-assisted surgery.

View Article and Find Full Text PDF

Introduction: Pulmonary vein isolation (PVI) lesions after cryoballoon ablation (CBA) are wide and continuous, however, the distribution can depend on the pulmonary vein (PV) size. We sought to assess the relationship between the lesion distribution and PV size after CBA and hotballoon ablation (HBA).

Methods And Results: A total of 80 consecutive patients who underwent PVI were enrolled (40 with CBA).

View Article and Find Full Text PDF

Background: There has been no effective method to predict ischemic intolerance to temporary internal carotid artery (ICA) occlusion during carotid artery reconstruction. Pencil beam presaturation (BeamSAT) pulse suppresses the flow signal of the target vessel in magnetic resonance angiography (MRA). Applying this method, we constructed ICA-selective MRA images.

View Article and Find Full Text PDF

During liver computed tomography (CT), scanning is performed with the raised arm position and an inhalation technique. However, for liver magnetic resonance imaging (MRI), the arms are placed at the sides of the body and an exhalation technique is used. This study was aimed at evaluating the effect that the patient's arm position and respiration technique had on the ability to detect mammary glands in the scan range to discover unexpected mammary lesions during the liver MRI examination.

View Article and Find Full Text PDF

Background: Rhythm outcomes after the pulmonary vein isolation (PVI) using the cryoballoon (CB) are reported to be excellent. However, the lesions after CB ablation have not been well discussed. We sought to characterize and compare the lesion formation after CB ablation with that after radiofrequency (RF) ablation.

View Article and Find Full Text PDF

This study aimed to compare dosimetric parameters between non-optimized and optimized treatment planning (NOP and OP, respectively) of magnetic resonance imaging (MRI) -based intracavitary (IC) image-guided adaptive brachytherapy (IGABT) using the central shielding (CS) technique for cervical cancer. Fifty-three patients treated with external beam radiotherapy using CS and MRI-based IGABT with the IC approach alone were evaluated. The total high-risk clinical target volume (HR-CTV) D90 was aimed at >70 Gy equivalent dose in 2 Gy fractions (EQD2).

View Article and Find Full Text PDF

To obtain objective and concrete data by physically assessing the quality of breast magnetic resonance images based on the fat-suppression effect by the modified Dixon method (mDixon) and frequency-selective fat suppression (e-Thrive) using an original lipid-content breast phantom that could easily reveal the influence of non-uniform fat suppression in breast magnetic resonance imaging. The fat-suppression uniformity was approximately seven times superior when using mDixon compared with when using e-Thrive. mDixon appears to have a significant advantage.

View Article and Find Full Text PDF

Purpose: To directly compare fat suppression efficacy of Dixon, spectral attenuated inversion recovery (SPAIR) and short tau inversion recovery (STIR) techniques for a 3T MR system.

Materials And Methods: Nineteen consecutive patients (11 men, 8 women; mean age 67.9years) underwent chest MR imaging.

View Article and Find Full Text PDF

It is sometimes difficult to distinguish gliomas from other tumors on routine imaging. In this study, we assessed whether 3-T magnetic resonance spectroscopy (MRS) with LCModel software might be useful for discriminating glioma from other brain tumors, such as primary central nervous system lymphomas (PCNSLs) and metastatic tumors. A total of 104 cases of brain tumor (66 gliomas, 20 PCNSLs, 6 metastatic tumors, 12 other tumors) were preoperatively investigated with short echo time (35 ms) single-voxel 3-T MRS.

View Article and Find Full Text PDF

Purpose: To investigate the impact of three-dimensional (3D) T2-weighted turbo spin-echo imaging (TSE-T2WI) with tissue-specific variable refocusing flip angle (TS-VRFA) on image quality and prostate cancer (PCa) detection and extraprostatic extension (EPE) evaluation compared to 2D TSE-T2WI and conventional 3D TSE-T2WI with volume isotropic TSE acquisition (VISTA).

Materials And Methods: Image data sets of 40 patients who underwent 3-T MRI before prostatectomy, including multiplane 2D T2WI, 3D T2WI with TS-VRFA and VISTA, and diffusion-weighted images were independently evaluated by two radiologists. The detectability of PCa and EPE of each sequence was assessed using areas by the receiver operating characteristic curve (AUC) analysis.

View Article and Find Full Text PDF

Aims/introduction: Whereas some clinical studies have shown that excessive fat accumulation in the pancreas is associated with impairment of insulin secretion, others have not found such an association. H magnetic resonance spectroscopy allows quantitative fat analysis in various tissues including the pancreas. The pathological relevance of pancreatic fat content (PFC) in Japanese individuals remains unclear, however.

View Article and Find Full Text PDF

Background: Mutations in the isocitrate dehydrogenase 1 (IDH1) gene that are frequently observed in low-grade glioma are strongly associated with the accumulation of 2-hydroxyglutarate (2HG), which is a valuable diagnostic and prognostic biomarker of IDH1 mutant glioma. However, conventional MR spectroscopy (MRS)-based noninvasive detection of 2HG is challenging. In this study, we aimed to determine the additional value of other metabolites in predicting IDH1 mutations with conventional MRS.

View Article and Find Full Text PDF

Background: To evaluate more detailed information noninvasively through on diffusion and perfusion in prostate cancer (PCa) using triexponential analysis of diffusion-weighted imaging (DWI).

Methods: Sixty-three prostate cancer patients underwent preoperative 3.0 Tesla MRI including eight b-values DWI.

View Article and Find Full Text PDF

Purpose: After cranioplasty with a titanium mesh, radiofrequency (RF)-shielding images appear during magnetic resonance (MR) imaging. To clarify their influence, we evaluated the effect of mesh position, phase-encoding direction, and type of coil employed.

Materials And Methods: On a 1.

View Article and Find Full Text PDF

Purpose: Separate assessment of changes in blood oxygenation and blood volume is required in blood oxygen level-dependent (BOLD) imaging. We developed a calculated echo time (TE) imaging technique designed to minimize effects of blood oxygenation and to evaluate blood volume specifically.

Materials And Methods: Dynamic 3T multi-echo BOLD images of calf muscle were acquired from six healthy volunteers by use of a cuff-compression model.

View Article and Find Full Text PDF

Purpose: The role of early stage functional assessment of muscle blood flow response (MFR) by dynamic muscle blood oxygen level-dependent (BOLD) magnetic resonance (MR) imaging is unknown. We investigated the effect of smoking on vascular function according to MFR derived from dynamic muscle BOLD MR imaging during postocclusive reactive hyperemia in young smokers and nonsmokers.

Methods: Sixteen healthy male volunteers (8 smokers, 8 nonsmokers; mean age, 30.

View Article and Find Full Text PDF

The mechanistic target of rapamycin (mTOR) is hyperactivated in many types of cancer, rendering it a compelling drug target; however, the impact of mTOR inhibition on metabolic reprogramming in cancer is incompletely understood. Here, by integrating metabolic and functional studies in glioblastoma multiforme (GBM) cell lines, preclinical models, and clinical samples, we demonstrate that the compensatory upregulation of glutamine metabolism promotes resistance to mTOR kinase inhibitors. Metabolomic studies in GBM cells revealed that glutaminase (GLS) and glutamate levels are elevated following mTOR kinase inhibitor treatment.

View Article and Find Full Text PDF

To evaluate the details of myocardial dysfunction in dilated cardiomyopathy (DCM) patients using tagging images and the correlation of tagging imaging with tissue characteristics. Circumferential strain (Ecc) derived from tagging images was measured in 15 normal (NML) subjects (15 males; mean age 28.5 years) and 12 DCM patients (7 males; mean age 48.

View Article and Find Full Text PDF

Myocardial edema and inflammation play an important role in dilated cardiomyopathy (DCM). This pathologic condition can be identified noninvasively using cardiovascular magnetic resonance imaging (CMR). The purpose of this study was to determine the effectiveness of T2 values obtained with T2 mapping in the detection of edema in DCM patients, compared with that of conventional T2-weighted imaging (T2WI).

View Article and Find Full Text PDF

A PHP Error was encountered

Severity: Notice

Message: fwrite(): Write of 34 bytes failed with errno=28 No space left on device

Filename: drivers/Session_files_driver.php

Line Number: 272

Backtrace:

A PHP Error was encountered

Severity: Warning

Message: session_write_close(): Failed to write session data using user defined save handler. (session.save_path: /var/lib/php/sessions)

Filename: Unknown

Line Number: 0

Backtrace: