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PURPOSE Computed tomography (CT)-based attenuation correction (CTAC) in single-photon emission computed tomography (SPECT) is highly accurate, but it requires hybrid SPECT/CT instruments and additional radiation exposure. To obtain attenuation correction (AC) without the need for additional CT images, a deep learning method was used to generate pseudo-CT images has previously been reported, but it is limited because of cross-modality transformation, resulting in misalignment and modality-specific artifacts. This study aimed to develop a deep learning-based approach using non-attenuation-corrected (NAC) images and CTAC-based images for training to yield AC images in brain-perfusion SPECT. This study also investigated whether the proposed approach is superior to conventional Chang's AC (ChangAC). METHODS In total, 236 patients who underwent brain-perfusion SPECT were randomly divided into two groups: the training group (189 patients; 80%) and the test group (47 patients; 20%). Two models were constructed using Autoencoder (AutoencoderAC) and U-Net (U-NetAC), respectively. ChangAC, AutoencoderAC, and U-NetAC approaches were compared with CTAC using qualitative analysis (visual evaluation) and quantitative analysis (normalized mean squared error [NMSE] and the percentage error in each brain region). Statistical analyses were performed using the Wilcoxon signed-rank sum test and Bland-Altman analysis. RESULTS U-NetAC had the highest visual evaluation score. The NMSE results for the U-NetAC were the lowest, followed by AutoencoderAC and ChangAC (P

Staff are exposed to radiation in the scanning room when assisting with CT scans of patients requiring ventilatory support during procedures. We measured lens doses using a phantom during a high-energy trauma protocol. Dosimetry showed that the unprotected lens received 2.02 mGy on the right and 1.91 mGy on the left, which are not negligible doses. Respective exposures to the right and left lens were 53.6% and 55.1% when wearing 0.07 mm Pb protective glasses with side covers; 53.7% and 64.2% when wearing 0.7 mm Pb glasses without side covers when facing away from the patient couch; and 92.1% and 91.2% using protective shielding in the gantry. Since the face direction may change during assistance with CT imaging, it is desirable that the protective glasses have a shape with a side cover. The protective shielding had a major radiation reduction effect, although it is expensive to acquire, install, and maintain.

Purpose Using a pediatric head phantom constructed in our department, we examined a method to reduce exposure by using organ-effective modulation (OEM; Toshiba Medical Systems Corporation, Tochigi) to tilt the gantry during pediatric head computed tomography (CT) scanning. Method The radiation reduction and CT image standard deviation (SD) were measured at gantry angles at which the orbit was slightly irradiated, partially irradiated, and completely irradiated. The OEM incident surface dose reduction rate was measured using an automatic exposure control (AEC) phantom with a diameter of 6-18 cm. Results The lens surface dose reduction rate using OEM was 21.2%. When the gantry was tilted and the orbit was completely out of the scanning range, the rate of reduction was 47.8%. OEM incident surface dose reduction rates were 27.4% for a phantom diameter of 18 cm, 22.0% for that of 16 cm, 17.8% for that of 14 cm, 17.2% for that of 12 cm, 8.4% for that of 10 cm, and 0% for that of 8 cm and 6 cm. OEM effectiveness decreased with decreasing phantom diameter. The use of OEM increased the rate of change of SD by 1.25´ when the gantry inclination was 0°, 1.27´ when the gantry inclination was 10°, and 1.27´ when the gantry inclination was 20°in the 12 o'clock position. Conclusion The degree of reduction in exposure dose to the lens in pediatric head CT imaging was 47.8% by completely removing the lens from the irradiation range using gantry tilt and 21.2% by using OEM. The effect of OEM changed in proportion to tube current. The exposure reduction effect of the OEM decreases with decreasing head size, indicating its reduced effectiveness in head CT scans of smaller infants.

Study DesignRetrospective observational study.PurposeLumbar spinal stenosis (LSS) has traditionally been evaluated morphologically, there is a paucity of literature on quantitative assessment of LSS. The purpose of this study was to investigate whether intraspinal diffusion tensor imaging (DTI) parameters such as apparent diffusion coefficient (ADC) and fractional anisotropy (FA) are useful for assessing LSS.Overview of LiteratureQuantitative assessment of LSS is challenging.MethodsStudy participants comprised five healthy volunteers (mean age, 27.2 years) and 27 patients with LSS (mean age, 58.4 years) who were individually assessed using 3.0 Tesla magnetic resonance imaging. Intraspinal ADC and FA values of 10 intervertebral discs from healthy volunteers and 52 intervertebral discs from LSS patients were measured. Also, intraspinal canal area, Schizas classification (A: normal, B: mild stenosis, C: severe stenosis) and correlations with symptoms were investigated. Clinical symptoms were checked for the presence of low back pain (LBP), intermittent claudication (IMC), and bladder and bowel dysfunction (BBD).ResultsCompared to healthy individuals, LSS patients had significantly lower ADC (pppr=0.63, pp=−0.61, pppConclusionsIntraspinal DTI parameters such as ADC and FA values were associated with the Schizas classification, intraspinal canal area, and clinical symptoms, suggesting that ADC and FA may be useful for quantitative assessment of LSS.

To evaluate the feasibility of coronary vessel wall visualization using three-dimensional turbo spin-echo black blood imaging (3D-TSE) in children with Kawasaki disease.Nine patients (6 girls and 3 boys; mean age ± standard deviation, 5.6 ± 3.3 years; range, 1.4-10.3 years) were included. Coronary magnetic resonance angiography (MRA) with an axial slice orientation and 3D-TSE with axial and sagittal slice orientations (3D-TSE-axi and 3D-TSE-sag) were acquired for the whole heart. Coronary vessel walls were evaluated separately in aneurysm and normal-proximal regions. The internal diameter and wall thickness of the reformatted cross-sectional images were measured in both the regions. Reproducibility between MRA and 3D-TSE was evaluated via interclass correlation coefficients (ICCs) and Bland-Altman plots.In total, 164 points (aneurysmal regions, 73; normal-proximal regions, 64; normal-distal regions, 27) were evaluated. The ICC for 3D-TSE-axi was higher than that for 3D-TSE-sag (aneurysmal regions, ICC = 0.88 and 0.81; normal-proximal regions, ICC = 0.90 and 0.32, respectively). Bland-Altman plots of the internal diameter via MRA and 3D-TSE-axi showed a wide 95% limit of agreement (-0.13 to 2.89 mm) and significant fixed and proportional biases (P 0.001 and P = 0.002) in the aneurysmal regions. However, the 95% limit of agreement was narrow (-0.14 to 0.57 mm) in the normal-proximal regions. If 1 mm was set as the cut-off for a thickened wall, wall thickness via 3D-TSE-axi was found to be abnormal across many points (84.0% of aneurysmal regions; 18.4% of normal-proximal regions).3D-TSE imaging of the normal-proximal regions of the coronary vessel in individuals with Kawasaki disease was found to be feasible. However, in aneurysmal regions, larger aneurysmal diameters led to an increased bias between MRA and 3D-TSE.

Purpose In 2011, the International Commissionon Radiological Protection (ICRP) recommended reducing the threshold dose for the lens. Therefore, it is important to reduce the lens exposure dose in medical exposures. In a cranio-caudal (CC) view of mammography, the patient' s lens receives scattered radiation. In this study, we investigated scatter dose around the lens during mammography and reviewed the simple and easy protection methods of the lens. Methods Optically stimulated luminescence (OSL) dosimeters were placed in front of the device to obtain scattered radiation intensity distribution. The human phantom was placed in the same way as the CC positioning, and BR-12 phantoms with a thickness of 40 mm was placed on the FPD. Then, the scatter dose around the lens was measured using an OSL dosimeter. In order to confirm the change in the scatter radiation dose by the face guard (FG) and eyelid, we measured and compared under the same conditions the presence of FG and adipose tissue about 1 mm thick assuming the eyelid. Results Scatter radiation intensity decreased around the FG. When the FG was installed, the scatter dose was reduced about 33%, and when the adipose tissue was pasted on the OSL dosimeter, the scatter dose was reduced about 29%. Conclusion This study suggested that eye closure during mammography was effective in reducing lens exposure. In the future, we would like to expect further protective effects by increasing the thickness of FG and reviewing the materials.

Rationale and Objectives Changes in the geometry of the chest wall due to lung hyperinflation occur in COPD. However, the quantitative assessment of impaired lung motions and its association with the clinical characteristics of COPD patients are unclear. This study aimed to investigate the respiratory kinetics of COPD patients by dynamic MRI. Materials and Methods This study enrolled 22 COPD patients and 10 normal participants who underwent dynamic MRI and pulmonary function testing (PFT). Changes in the areas of the lung and mediastinum during respiration were compared between the COPD patients and the normal controls. Relationships between MRI, CT parameters, and clinical measures that included PFT results also were evaluated. Results Asynchronous movements and decreased diaphragmatic motion were found in COPD patients. COPD patients had a larger ratio of MRI-measured lung areas at expiration to inspiration, a smaller magnitude of the peak area change ratio, and a smaller mediastinal-thoracic area ratio than the normal participants. The lung area ratio was associated with FEV1/FVC, predicted RV%, and CT lung volume/predicted total lung capacity (pTLC). The lung area ratio of the right lower and left lower lungs was significantly correlated with emphysema of each lower lobe. The expiratory mediastinal-thoracic area ratio was associated with FEV1% predicted and RV/TLC. Conclusion Changes in the lung areas of COPD patients as shown on MRI reflected the severity of airflow limitation, hyperinflation, and the extent of emphysema. Dynamic MRI provides essential information about respiratory kinetics in COPD.

Objective: The aim was to compare the fractional anisotropy (FA) and apparent diffusion coefficient (ADC) values of the sciatic and femoral nerves in patients with unilateral osteoarthritis of the ...

Previous studies have reported the utility of diffusion tensor imaging (DTI) as an imaging biomarker for the severity of myelopathy and subsequent surgical outcome in patients with degenerative cervical myelopathy (DCM). We hypothesized that DTI may reflect neurological recovery following surgery. The purpose of this study was to evaluate the ability of DTI to assess the post-operative alteration of neural status in patients with DCM as well as to predict post-operative recovery. We enrolled 15 patients with DCM who underwent decompression surgery. The Japanese Orthopaedic Association (JOA) score was evaluated before and 1 year after surgery. The participants were examined using DTI on a 3.0 T magnetic resonance scanner before, and 1 year after surgery. Fractional anisotropy (FA) and mean diffusivity (MD) were assessed for both time points. The correlations between the pre- and post-operative FA and MD values and the pre- and post-operative JOA scores were analyzed. Although the JOA score improved significantly after surgery from 8.9 to 12.3, there was no significant change between the pre- and post-operative FA and MD values. The post-operative outcomes after 1 year moderately correlated with the pre-operative FA values (Spearman’s ρ = 0.55, p = 0.03 and Spearman’s ρ = 0.56, p = 0.03 for change and recovery rate of the JOA score, respectively). However, there was no correlation between the post-operative FA and post-operative JOA scores nor between MD and clinical outcomes. DTI cannot be utilized as a biomarker for post-operative alterations of neural status of the spinal cord; however, pre-operative DTI may be useful as a predictor of surgical outcomes.

Organ-effective modulation (OEM) is a mechanism to reduce radiation dose to selected organs on computed tomography (CT). The purpose of this study was to measure radiation dose to the breast in Asian patients undergoing chest CT and to clarify the degree of exposure reduction.We randomly selected 60 female patients undergoing non-contrast chest CT after breast cancer surgery. To measure radiation dose, an optically stimulated luminescence dosimeter had been attached directly to the gown over the nonoperated breast in 30 patients. Radiologists evaluated the image quality with and without OEM. In order to clarify the characteristics of OEM, the effects of angle and object size were measured using a phantom and an ionization chamber dosimeter.The OEM group received 9.1 ± 1.9 mGy and the non-OEM group received 10.7 ± 2.4 mGy. OEM reduced the exposure by 12.2% (P 0.01). OEM caused no reduction in diagnostic quality. In the phantom study, the results of the angle effect were 3.2%, 11.2%, 28.7%, 31.3, 25.9%, 14.9% and 6.0% dose reductions at -90, -60, -30, 0, 30, 60 and 90°, respectively. The effect of the subject thickness was 3.7%, 17.5%, 30.2%, 31.7%, and 34.1% at 16, 20, 24, 28 and 32 cm diameters, respectively.OEM is a useful mechanism for reducing radiation exposure to the breast without affecting diagnostic imaging quality. The reduction rate correlated negatively with body habitus.

Patients with cervical compression myelopathy (CCM) generally present bilateral neurological symptoms in their extremities. However, a substantial portion of patients with CCM exhibit laterality of neurological symptoms. The aim of this study was to assess the correlation between intrinsic structural damage and laterality of symptoms using spinal cord diffusion tensor imaging (DTI) of the corticospinal tract.We enrolled 10 healthy volunteers and 40 patients with CCM in this study. We evaluated motor function using the American Spinal Injury Association (ASIA) motor score for left and right extremities. For DTI acquisitions, a 3.0-T magnetic resonance imaging system with diffusion-weighted spin-echo sequence was used. Regions-of-interest in the lateral column tracts were determined. We determined the correlations between fractional anisotropy (FA) and ASIA motor scores. An FA asymmetry index was calculated using left and right regions-of-interest.Four patients exhibited laterality of symptoms in their extremities, for which left and right ASIA scores correlated moderately with FA in the left and right lateral columns, respectively (left: ρ = 0.64, P0.001; right: ρ = 0.67, P0.001). The area under the receiver-operator characteristic curve showed that the FA asymmetry index indicated laterality of symptoms.Using tract-specific DTI, we demonstrated that microstructural damages in the left and right corticospinal tracts correlated with corresponding neurological symptoms in the ipsilateral side and the FA asymmetry index could indicate laterality in neurological symptoms of patients with CCM.

ObjectiveTo investigate the relationship between the severities of symptom dimensions in obsessive-compulsive disorder (OCD) and white matter alterations.MethodsWe applied tract-based spatial statistics for diffusion tensor imaging (DTI) acquired by 3T magnetic resonance imaging. First, we compared fractional anisotropy (FA) between 20 OCD patients and 30 healthy controls (HC). Then, applying whole brain analysis, we searched the brain regions showing correlations between the severities of symptom dimensions assessed by Obsessive-Compulsive Inventory-Revised and FA in all participants. Finally, we calculated the correlations between the six symptom dimensions and multiple DTI measures [FA, axial diffusivity (AD), radial diffusivity (RD), mean diffusivity (MD)] in a region-of-interest (ROI) analysis and explored the differences between OCD patients and HC.ResultsThere were no between-group differences in FA or brain region correlations between the severities of symptom dimensions and FA in any of the participants. ROI analysis revealed negative correlations between checking severity and left inferior frontal gyrus white matter and left middle temporal gyrus white matter and a positive correlation between ordering severity and right precuneus in FA in OCD compared with HC. We also found negative correlations between ordering severity and right precuneus in RD, between obsessing severities and right supramarginal gyrus in AD and MD, and between hoarding severity and right insular gyrus in AD.ConclusionOur study supported the hypothesis that the severities of respective symptom dimensions are associated with different patterns of white matter alterations.

Study objectives Animal studies suggest a pivotal role of the hyoid bone in obstructive sleep apnea (OSA). We aimed to explore the role of the hyoid bone in humans by testing the hypotheses that muscle paralysis and lung volume (LV) changes displace the hyoid bone position particularly in people with obesity and/or OSA. Methods Fifty patients undergoing general anesthesia participated in this study (20 participants with nonobese, non-OSA; 8 people with nonobese OSA; and 22 people with obese OSA). Three lateral neck radiographs to assess the hyoid position (primary variable) and craniofacial structures were taken during wakefulness, complete muscle paralysis under general anesthesia, and LV increase under general anesthesia. LV was increased by negative extrathoracic pressure application and LV changes were measured with a spirometer. Analysis of covariance was used to identify statistical significance. Results Muscle paralysis under general anesthesia significantly displaced the hyoid bone posteriorly (95% CI: 1.7 to 4.6, 1.5 to 5.2, and 1.1 to 4.0 mm in nonobese non-OSA, nonobese OSA, and obese OSA groups, respectively), and this was more prominent in people with central obesity. LV increase significantly displaced the hyoid bone caudally in all groups (95% CI: 0.2 to 0.7, 0.02 to 0.6, and 0.2 to 0.6 mm/0.1 liter LV increase in nonobese non-OSA, nonobese OSA, and obese OSA groups, respectively). Waist-hip ratio was directly associated with the caudal displacement during LV increase. Conclusions The hyoid bone plays an important role in the pathophysiology of pharyngeal airway obstruction due to muscle paralysis and LV reduction, particularly in people with obesity. Clinical trial UMIN Clinical Trial Registry, https://upload.umin.ac.jp/cgi-open-bin/ctr/ctr_view.cgi?recptno=cR000022635&language=E, UMIN000019578.

Obsessive-compulsive disorder (OCD) is among the most debilitating psychiatric disorders. Comorbid autism spectrum disorder (ASD) or autistic traits may impair treatment response in OCD. To identify possible neurostructural deficits underlying autistic traits, we performed white matter tractography on diffusion tensor images (DTI) and assessed autistic trait severity using the Autism-Spectrum Quotient (AQ) in 33 OCD patients. Correlations between AQ and the DTI parameters, fractional anisotropy (FA), mean diffusivity (MD), axial diffusivity (AD), and radial diffusivity (RD) were examined in major white matter tracts that were suggested to be altered in previous OCD studies. We found a negative correlation between AQ and FA and positive correlations between AQ and MD, AD and RD in the left uncinate fasciculus using age, Beck Depression Inventory, Yale-Brown Obsessive-Compulsive Scale, intelligence quotient and medication as covariates. However, we could not detect the significant results between AQ and all DTI parameters when adding gender as a covariate. In addition, in the ASD comorbid group, FA in the left uncinate fasciculus was significantly lower than in the non-ASD comorbid group and MD and RD were significantly higher than in the non-ASD group. These results did not survive correction for multiple comparisons. In ASD, the socio-emotional dysfunction is suggested to be related to the alteration of white matter microstructure in uncinate fasciculus. Our results suggest that variations in white matter features of the left uncinate fasciculus might be partly explained by autistic traits encountered in OCD patients.

Recommended acquisition-parameters in achieving successful evaluation of coronary lumen patency surrounded by XIENCE of diameters b3.0 mm in 1st generation 320-slice CT. XIENCE Phantom Study Part 1 Nobusada Funabashi ⁎, Yasuaki Namihira , Ryosuke Irie , Yoshihide Fujimoto , Toshihiro Shoji , Hiroyuki Takaoka , Hironori Kondo , Kanako Atou , Joji Ota , Yoshitada Masuda , Takashi Uno , Yoshio Kobayashi a

Although abdominal aortic aneurysms (AAAs) occur mostly inferior to the renal artery, the mechanism of the development of AAA in relation to its specific location is not yet clearly understood. The objective of this study was to evaluate the hypothesis that even healthy volunteers may manifest specific flow characteristics of blood flow and alter wall shear or oscillatory shear stress in the areas where AAAs commonly develop. Eight healthy male volunteers were enrolled in this prospective study, aged from 24 to 27. Phase-contrast magnetic resonance imaging (MRI) was performed with electrocardiographic triggering. Flow-sensitive four-dimensional MR imaging of the abdominal aorta, with three-directional velocity encoding, including simple morphological image acquisition, was performed. Information on specific locations on the aortic wall was applied to the flow encodes to calculate wall shear stress (WSS) and oscillatory shear index (OSI). While time-framed WSS showed the highest peak of 1.14 ± 0.25 Pa in the juxtaposition of the renal artery, the WSS plateaued to 0.61 Pa at the anterior wall of the abdominal aorta. The OSI peaked distal to the renal arteries at the posterior wall of the abdominal aorta of 0.249 ± 0.148, and was constantly elevated in the whole abdominal aorta at more than 0.14. All subjects were found to have elevated OSI in regions where AAAs commonly occur. These findings indicate that areas of constant peaked oscillatory shear stress in the infra-renal aorta may be one of the factors that lead to morphological changes over time, even in healthy individuals.

Recently several authors have reported that diffusion tensor imaging (DTI) might provide a new understanding of sciatica. The purpose of this study was to investigate the clinical feasibility of DTI for the evaluation of lumbar spinal nerve of patients with sciatica associated with lumbar degenerative disorders. Thirty-four patients (25men, mean age63. 3years) with degenerated lumbar disease, 14 patients with lumbar spinal stenosis with foraminal stenosis, 12 with lumbar spinal stenosis without foraminal stenosis, five with lumbar disc herniation, two with discogenic low back pain, and one with spondylolysis who underwent 3.0T magnetic resonance (MR) imaging and surgical treatment were included in the present study. Fractional anisotropy (FA) was calculated from an FA map, and tractography was investigated. In asymptomatic nerves, tractography showed all L3-S1 spinal nerve roots clearly. Abnormalities of tractography were classified into three types by shape; "Disrupted", "Narrowing", and "Tapering". More abnormalities of tractography were found in patients with lumbar spinal stenosis, and especially in patients with foraminal stenosis. The disrupted type was the most common. The mean FA of entrapped symptomatic nerves was less than seen on the intact side. This study demonstrates that tractography shows abnormal findings for nerve roots in lumbar spinal degeneration and that FA decreases in symptomatic roots. DTI may offer not only morphological evaluation, but also quantitative evaluation. We believe that DTI can be used as a tool for the diagnosis of lumbar spinal degenerative disease.

OBJECTIVES Obsessive-compulsive disorder (OCD) is one of the most debilitating psychiatric disorders, with some speculating that a reason for difficulty in its treatment might be its coexistence with autism spectrum. We investigated the tendency for autistic spectrum disorders (ASD) in patients with OCD from a neuroimaging point of view using voxel-based morphometry. METHODS We acquired T1-weighted images from 20 patients with OCD and 30 healthy controls and investigated the difference in regional volume between the groups as well as the correlation between Autism-Spectrum Quotient (AQ) scores and regional cerebral volumes of patients with OCD. RESULTS Volumes in the bilateral middle frontal gyri were significantly decreased in patients with OCD compared to controls. Correlational analysis showed significant positive correlations between AQ scores and regional gray matter (GM) volumes in the left dorsolateral prefrontal cortex (DLPFC) and left amygdala. Furthermore, GM volumes of these regions were positively correlated with each other. CONCLUSIONS The positive correlation of ASD traits in patients with OCD with regional GM volumes in the left DLPFC and amygdala could reflect the heterogeneity of patient symptoms. Our results suggest that differences in GM volume might allow classification of patients with OCD for appropriate therapy based on their particular traits.

Background The aim was to clarify the normal fractional anisotropy (FA) and apparent diffusion coefficient (ADC) values of the sciatic and femoral nerves at the level of the hip joint and to visualize the neural tracts with diffusion tensor imaging (DTI). Methods Twenty-four healthy volunteers (12 men and 12 women, age 20–29 years) underwent DTI for visualization with tractography and quantification of FA and ADC values on a 3 Tesla MRI (b value = 800 s/mm2, motion probing gradient, 11 directions, time to repeat/echo time = 9000/72.6 ms, axial slice orientation, slice thickness = 3.0 mm with no inter-slice gap, field of view = 320 × 320 mm, 96 × 192 matrix, 75 slices, number of acquisitions = 4). Regions of interest in the sciatic nerve were defined at the femoral head, the S1 root, and the midpoint levels. The femoral nerve was evaluated at 3–4 cm proximal to the femoral head level. Results The tractography of the sciatic and femoral nerves were visualized in all participants. The mean FA values of the sciatic nerve were increased distally from the S1 root level, through the midpoint, and to the femoral head level (0.314, 0.446, 0.567, p = 0.001, respectively). The mean FA values of the femoral nerve were 0.565. The mean ADC values of the sciatic nerves were significantly lower in the S1 root level than in the midpoint and the femoral head level (1.481, 1.602, 1.591 × 10−3 × 10−3 mm2/s, p = 0.001, respectively). The ADC values of the femoral nerve were 1.439 × 10−3 mm2/s. FA and ADC values showed moderate to substantial inter- and intra-observer reliability without significant differences in gender or laterality. Conclusion Visualization and quantification of the sciatic and femoral nerves simultaneously around the hip joint were achieved in healthy young volunteers with DTI. Clinical application of DTI is expected to contribute to hip pain research.

To document the reliability of Abe's classification and to clarify the predictive factors for acetabular labral lesions in osteoarthritis of the hip with radial magnetic resonance (MR) imaging.Reliability trial for the classification of acetabular labral lesion was performed by six orthopedic surgeons, grading 20 radial MR images in a blinded fashion at an interval of 4-5 weeks. Radial MR images of 275 hips in 263 patients were prospectively analyzed to determine the relationship between acetabular labral lesions, their distribution, age, and the acetabular coverage.Cohen's quadratic weighted kappa of inter-observer reliability was 0.784 for the grade and 0.812 for the shape category. The weighted kappa of intra-observer reliability was 0.852 for the grade and 0.90 for the shape category. Multiple regression analysis revealed that both the grade and the shape were associated with age, acetabular coverage, and location of the labrum.Abe's classification of labral lesions was reliable for both the grade and shape categories. Aging, acetabular dysplasia, and the anterosuperior portion would be predictive factors for degeneration of the acetabular labrum using radial MR imaging.

Optical stent-sizes in evaluating patency of coronary lumen surrounded by XIENCE of actual diameters 2.21–2.85 mm in 1st-generation 320-slice-CT using Pulsating-Phantom XIENCE phantom study part 5 Nobusada Funabashi ⁎, Yasuaki Namihira , Ryosuke Irie , Yoshihide Fujimoto , Toshihiro Shoji , Hiroyuki Takaoka , Hironori Kondo , Kanako Atou , Joji Ota , Yoshitada Masuda , Takashi Uno , Yoshio Kobayashi a

The purpose of the present study was to evaluate the usefulness of coronal reformatted images obtained from 64-slice multi-detector computed tomography to assess the ablative margin (AM) in hepatocellular carcinoma (HCC) treated with radio frequency ablation (RFA). Ninety-five HCC nodules were analyzed in 66 HCC patients treated with RFA. Two radiologists and one hepatologist independently reviewed axial CT images with or without coronal reformatted images in HCC treated with RFA. Nodules were determined as AM-sufficient (≥5 mm) or AM-insufficient (

PURPOSE: The aim of this study was to assess the potential role of diffusion tensor imaging (DTI) as a predictor of surgical outcomes in patients with cervical compressive myelopathy (CCM). Surgical decompression is often recommended for symptomatic CCM. It is important to know the prognosis of surgical outcomes and to recommend appropriate timing for surgery. \nMETHODS: We enrolled 26 patients with CCM who underwent surgery. The Japanese Orthopaedic Association (JOA) score for cervical myelopathy was evaluated before and 6 months after surgery. Surgical outcomes were regarded as good if there was a change in JOA score of three points or more, or the recovery rate of JOA score was 50% or more. The patients were examined using a 3.0 T magnetic resonance system before surgery. Measured diffusion parameters were fractional anisotropy (FA) and mean diffusivity (MD). The correlations between DTI parameters and surgical outcomes were analyzed. \nRESULTS: Both change and recovery rate of JOA score moderately correlated with FA. Furthermore, the area under the receiver-operator characteristic curve based on FA for prognostic precision of surgical outcomes indicates that FA is a good predictive factor. The cut-off values of FA for predicting good surgical outcomes evaluated by change and recovery rate of JOA score were 0.65 and 0.57, respectively. Neither change nor recovery rate of JOA score correlated with MD. \nCONCLUSIONS: FA in spinal cord DTI can moderately predict surgical outcomes. DTI can serve as a supplementary tool for decision-making to guide surgical intervention in patients with CCM.

BACKGROUND AND PURPOSE: DTI can provide valuable structural information that may become an innovative tool in evaluating lumbar foraminal nerve root entrapment. The purpose of this study was to visualize the lumbar nerve roots and to measure their FA in healthy volunteers and patients with lumbar foraminal stenosis by using DTI and tractography with 3T MR imaging. MATERIALS AND METHODS: Eight patients with lumbar foraminal stenosis and 8 healthy volunteers underwent 3T MR imaging. In all subjects, DTI was performed with echo-planar imaging at a b-value of 800 s/mm2 and the lumbar nerve roots were visualized with tractography. Mean FA values in the lumbar nerve roots were quantified on DTI images. RESULTS: In all subjects, the lumbar nerve roots were clearly visualized with tractography. In all patients, tractography also showed abnormalities such as tract disruption, nerve narrowing, and indentation in their course through the foramen. Mean FA values were significantly lower in entrapped roots than in intact roots. CONCLUSIONS: We demonstrated that DTI and tractography of human lumbar nerves can visualize and quantitatively evaluate lumbar nerve entrapment with foraminal stenosis. We believe that DWI is a potential tool for the diagnosis of lumbar nerve entrapment.

Study design A retrospective observational study of healthy volunteers and patients with degenerative and infectious endplate abnormalities in the lumbar spine. Objectives Our purpose was to evaluate the usefulness of diffusion-weighted imaging (DWI) for the differentiation of degenerative and infectious endplate abnormalities using 1.5-T magnetic resonance imaging (MRI). Summary of background data DWI can provide valuable structural information about tissues that may be useful for clinical applications in differentiation between degenerative and infectious endplate abnormalities. Methods Sixteen consecutive patients with endplate abnormalities that was detected by MRI of the lumbar spine, and 15 healthy volunteers were studied. DWI was performed using whole-body imaging with background body signal suppression with a b value of 1000 s/mm2. Apparent diffusion coefficient values of normal and abnormal vertebral bone marrow were calculated. Results Twenty-nine vertebral abnormalities were found in 16 patients. Nine vertebral abnormalities in 5 patients were because of infections and 20 vertebral abnormalities in 11 patients were because of degenerative changes; 7 levels were classified as Modic type 1, 7 levels as type 2, and 6 levels as type 3. DWI showed hyperintensity in all patients with infection, similar to that used in positron emission tomography, but not in the intervertebral spaces of any patients with degenerative disease. Apparent diffusion coefficient values of infectious bone marrow were significantly higher than normal and degenerative bone marrow. Conclusion DWI is useful for differentiation of degenerative and infectious endplate abnormalities. Moreover, MRI is widely used clinically because of the lack of ionizing radiation, low cost, and fast imaging time as compared with positron emission tomography. Therefore, DWI has the potential to be used as a screening tool.

Diffusion-weighted imaging (DWI) can provide valuable structural information that may be useful for evaluating pathological changes of the lumbar nerve root. Diffusion-weighted magnetic resonance (MR) neurography has recently been introduced as an alternative way to visualize nerves, but to date, quantitative DWI and MR neurography have not been applied to evaluate the pathology of lumbar nerve roots.Our purpose was to visualize lumbar nerve roots and to analyze their morphology by MR neurography, and to measure the apparent diffusion coefficient (ADC) of lumbar nerve roots compressed by herniated disks using 1.5-T MR imaging. Ten consecutive patients (median age, 48.0 and range, 20-72 years) with monoradicular symptoms caused by a lumbar herniated disk and 14 healthy volunteers were studied. Regions of interests were placed on the lumbar roots at dorsal root ganglia (DRG) and distal spinal nerves on DWI to quantify mean ADC values. The spinal nerve roots were also visualized by MR neurography.In the patients, mean ADC values were significantly greater in the compressed DRG and distal spinal nerves than in intact nerves. MR neurography also showed abnormalities such as nerve swelling at and below the compression in the symptomatic nerve root. Increased ADC values were considered to be because of edema and Wallerian degeneration of compressed nerve roots.DWI is a potential tool for analysis of the pathophysiology of lumbar nerve roots compressed by herniated disks.

Multisector-reconstruction in 1st generation 320-slice CT at high pulsation-rates achieved accurate-evaluation of coronary-lumen patency after insertion of a XIENCE stent. XIENCE Phantom Study Part 4 Nobusada Funabashi ⁎, Yasuaki Namihira , Ryosuke Irie , Yoshihide Fujimoto , Toshihiro Shoji , Hiroyuki Takaoka , Hironori Kondo , Kanako Atou , Joji Ota , Yoshitada Masuda , Takashi Uno , Yoshio Kobayashi a

Study design A cross-sectional study. Objective The aim of this study was to quantify spinal cord dysfunction at the tract level in patients with cervical compressive myelopathy (CCM) using reduced field-of-view (rFOV) diffusion tensor imaging (DTI). Summary of background data Although magnetic resonance imaging (MRI) is the standard used for radiological evaluation of CCM, information acquired by MRI does not necessarily reflect the severity of spinal cord disorder. There is a growing interest in developing imaging methods to quantify spinal cord dysfunction. To acquire high-resolution DTI, a new scheme using rFOV has been proposed. Methods We enrolled 10 healthy volunteers and 20 patients with CCM in this study. The participants were studied using a 3.0-T MRI system. For DTI acquisitions, diffusion-weighted spin-echo rFOV single-shot echo-planar imaging was used. Regions-of-interest (ROI) for the lateral column (LC) and posterior column (PC) tracts were determined on the basis of a map of fractional anisotropy (FA) of the spinal cord and FA values were measured. The FA of patients with CCM was compared with that of healthy controls and correlated with Japanese Orthopaedic Association (JOA) score. Results In LC and PC tracts, FA values in patients with CCM were significantly lower than in healthy volunteers. Total JOA scores correlated moderately with FA in LC and PC tracts. JOA subscores for motor dysfunction of the lower extremities correlated strongly with FA in LC and PC tracts. Conclusion It is feasible to evaluate the cervical spinal cord at the tract level using rFOV DTI. Although FA values at the maximum compression level were not well correlated with total JOA scores, they were strongly correlated with JOA subscores for motor dysfunction of the lower extremities. Our findings suggest that FA reflects white matter dysfunction below the maximum compression level and FA can be used as an imaging biomarker of spinal cord dysfunction. Level of evidence 4.

Thoracic time-sequential MRI can be used to assess diaphragm motion pattern without exposing radiation to subject. Clinicians may employ the motion to evaluate the severeness of chronic obstructive pulmonary disease (COPD). This study proposed a novel method of diaphragm motion extraction method on time-sequential thoracic MRI in sagittal plane. Otsu’s threshold and active contour algorithm are used to obtain diaphragm boundary. An automatic diaphragm motion tracking and extraction of respiratory pattern are also performed based on the diaphragm boundary. A total of 1200 frames time-sequential MRI in sagittal plane was obtained for total of 15 subjects (8 healthy volunteers and 7 COPD patients). The proposed method successfully extracts diaphragm motion and respiratory patterns for both healthy volunteers and COPD patients. DOI: http://dx.doi.org/10.11591/telkomnika.v14i2.7375

We have developed a method called intersection profile method to construct a 4D-MRI (3D+time) from time-series of 2D-MRI. The basic idea is to find the best matching of the intersection profile from the time series of 2D-MRI in sagittal plane (navigator slice) and time series of 2D-MRI in coronal plane (data slice). In this study, we use 4D-MRI to semiautomatically extract the right diaphragm motion of 16 subjects (8 healthy subjects and 8 COPD patients). The diaphragm motion is then evaluated quantitatively by calculating the displacement of each subjects and normalized it. We also generate phase-length map to view and locate paradoxical motion of the COPD patients. The quantitative results of the normalized displacement shows that COPD patients tend to have smaller displacement compared to healthy subjects. The average normalized displacement of total 8 COPD patients is 9.4mm and the average of normalized displacement of 8 healthy volunteers is 15.3mm. The generated phase-length maps show that not all of the COPD patients have paradoxical motion, however if it has paradoxical motion, the phase-length map is able to locate where does it occur.

We investigated high resolution diffusion tensor imaging (DTI) of lumbar nerves with reduced field of view (rFOV) using 3 T MRI.DTI measured with rFOV was compared with conventional FOV (cFOV) 3.0 T MRI in 5 healthy volunteers and 10 patients with degenerative lumbar disorders. The intracanal, foramina and extraforamina of the L5 nerve were established as the regions of interest and fractional anisotropy (FA) values and apparent diffusion coefficient (ADC) values were measured. Image quality for tractography and FA maps and ADC maps, interindividual and intraindividual reliability of FA and ADC, and signal-to-noise (SNR) were studied.Both of image qualities with tractography, FA map and ADC map showed that lumbar nerves were more clearly imaged with the rFOV. Intraindividual reliability was higher with rFOV compared with the conventional method for ADC values, while interindividual reliability was higher for both FA values and ADC values with the rFOV method over the conventional method (p0.05). Significantly higher SNR was obtained with rFOV compared with cFOV in the spinal canal (p0.05).rFOV enabled clearer imaging of the lumbar nerve, allowing for more accurate measurement of FA and ADC values. Significantly higher SNR was obtained with rFOV compared with cFOV in the spinal canal. To our knowledge, this research showed for the first time the usefulness of rFOV in patients with degenerative lumbar disorders. High resolution DTI using rFOV may become useful in clinical applications because visualization of nerve entrapments and quantification of DTI parameters may allow more accurate diagnoses of lumbar nerve dysfunction. Advances in knowledge: Compared with traditional methods, rFOV allows for clear imaging of the lumbar nerve and enables accurate measurements of the FA and ADC values. High-resolution DTI with rFOV may be used to visualize nerve entrapments and allow for more accurate diagnosis of DTI parameter quantification with opportunities for clinical applications.

Background Alteration in shoulder kinematics has been suggested as one cause of symptoms in shoulders with rotator cuff tears (RCTs). However, only a few studies comparing symptomatic and asymptomatic RCTs using kinematic analysis have been performed. The purpose of this study was to compare 3-dimensional (3D) scapular and glenohumeral kinematics during scapular-plane abduction among symptomatic RCTs, asymptomatic RCTs, and healthy shoulders. Methods This study included 7 healthy shoulders in subjects with a mean age of 62 years, 5 symptomatic RCTs in subjects with a mean age of 70 years, and 7 asymptomatic RCTs in subjects with a mean age of 67 years. All shoulders with RCTs had medium-sized tears (1-3 cm in the coronal plane) that were confirmed with magnetic resonance imaging. Biplane fluoroscopic images during scapular-plane abduction were recorded, and computed tomography–derived 3D bone models were matched with the silhouettes of the bones on the fluoroscopic images using 3D/2-dimensional model-image registration techniques. Angular values of the scapula and glenohumeral kinematics were compared among the 3 groups. Results Posterior tilt of the scapula was significantly smaller in the symptomatic RCTs (3.1° ± 1.8°) than in healthy shoulders (10.4° ± 0.8°) (P = .049). The humerus of the symptomatic shoulders was less externally rotated relative to the scapula throughout the activity than the healthy shoulders and asymptomatic RCTs (P = .006 and P = .028 respectively). However, there were no kinematic differences between the asymptomatic RCTs and healthy shoulders. Conclusion Kinematic changes in symptomatic RCTs might be associated with development of symptoms. Improvement of these kinematic changes may be a key to successful conservative treatment for symptomatic RCTs.

Previously, we proposed a method for reconstructing 4D-MRI of thoracoabdominal organs that can visualize and quantify the three-dimensional dynamics of organs due to respiration. However, the data acquisition time of the method is long, say, 30 min. In this study, we assume an interleave acquisition of images with a smaller number of the encoding in the k-space to shorten the data acquisition time. We also propose to use a reconstruction technique named k-t SLR that utilizes sparse and low rank structures of the data matrix to avoid image degradation due to the small number of data acquisition. We performed a simulation experiment where we regarded 4D-MR images by our previous method as ideal images, generated down sampled data in k-space, and applied k-t SLR reconstruction to those data. We evaluated the resultant images from three viewpoints and confirmed that the combination of fast data collection with a small number of encoding and the subsequent k-t SLR reconstruction can produce high quality MR images.

We analyzed a statistical model of diaphragm motion using regular principal component analysis (PCA) and generalized N-dimensional PCA (GND-PCA). First, we generate 4D MRI of respiratory motion from 2D MRI using an intersection profile method. We then extract semiautomatically the diaphragm boundary from the 4D-MRI to get subject-specific diaphragm motion. In order to build a general statistical model of diaphragm motion, we normalize the diaphragm motion in time and spatial domains and evaluate the diaphragm motion model of 10 healthy subjects by applying regular PCA and GND-PCA. We also validate the results using the leave-one-out method. The results show that the first three principal components of regular PCA contain more than 98% of the total variation of diaphragm motion. However, validation using leave-one-out method gives up to 5.0 mm mean of error for right diaphragm motion and 3.8 mm mean of error for left diaphragm motion. Model analysis using GND-PCA provides about 1 mm margin of error and is able to reconstruct the diaphragm model by fewer samples.

Background Standard choledochal cyst (CC) operations involve dilated extrahepatic bile duct excision followed by biloenterostomy. However, biliary variants and associated intrahepatic bile duct (IHBD) stenoses or dilatations triggering postoperative sequelae require additional procedures. The usefulness of preoperative 3-dimensional magnetic resonance cholangiopancreatography (3D MRCP) and virtual cholangioscopy (VES) for observing biliary morphology and pancreaticobiliary maljunction (PBM) was evaluated. Methods In 16 pediatric CC patients (age range, 4 months to 9 years; median, 3 years), visualization of PBM and aberrant bile duct anatomy and IHBD morphology at the hepatic hilum (HH), umbilical portion (UP), and posterior branch (POST) were compared between 3D-MRCP and intraoperative cholangiography (IOC). VES and intraoperative cholangioscopy (IOS) findings were compared. Results HH, UP, and POST visualization rates were 100%, 94%, and 94%, respectively, by 3D-MRCP, and 100%, 69%, and 69%, respectively, by IOC. IHBD stenosis detection rates at each region were 38%, 13%, and 13%, respectively, by 3D-MRCP, and 25%, 0%, and 9%, respectively, by IOC. IHBD dilatation detection rates at each part were 75%, 47%, and 60%, respectively, by 3D-MRCP, and 88%, 82%, and 91%, respectively, by IOC. PBM was confirmed in 56% and 93% of cases on 3D-MRCP and IOC, respectively. Both 3D-MRCP and IOC showed biliary variants in 5 cases (31%). VES showed membranous strictures at HH, UP, and POST in 6, 2, and 2 cases, respectively, whereas IOS did so at HH in 4 cases and POST in 2. Conclusion Preoperative 3D-MRCP and VES accurately depict biliary morphology, allowing concrete operative planning in pediatric CC patients, complementing IOC and IOS.

We propose an intersection profile method for reconstructing a 4D-MRI of respiratory organ motion from time sequential images of 2D-MRI. In the proposed method, first, time sequential MR images in many coronal planes set to widely cover the lung region are acquired as the data slices. Second, the time sequential MR images in a proper sagittal plane are acquired as the navigator slice. 4D-MRI is reconstructed by extracting and combining a proper respiratory pattern from each data slice which is most similar to an adequately selected respiratory pattern in the navigator slice on the intersection between the navigation slice and each data slice. Successful visualization of the respiratory organ motion is demonstrated and the validation of reconstruction is also presented. Such a 4D-MRI has a great potential for many medical applications. In this paper, we further propose to construct a diaphragmatic function map from a 4D-MRI reconstructed by the intersection profile method to evaluate diaphragmatic motion quantitatively. Experimental results using three healthy volunteers and three patients are shown.

Diffusion-weighted imaging (DWI) can provide valuable structural information about tissues that may be useful for clinical applications in evaluating lumbar foraminal nerve root entrapment. Our purpose was to visualize the lumbar nerve root and to analyze its morphology, and to measure its apparent diffusion coefficient (ADC) in healthy volunteers and patients with lumbar foraminal stenosis using 1.5-T magnetic resonance imaging. Fourteen patients with lumbar foraminal stenosis and 14 healthy volunteers were studied. Regions of interest were placed at the fourth and fifth lumbar root at dorsal root ganglia and distal spinal nerves (at L4 and L5) and the first sacral root and distal spinal nerve (S1) on DWI to quantify mean ADC values. The anatomic parameters of the spinal nerve roots can also be determined by neurography. In patients, mean ADC values were significantly higher in entrapped roots and distal spinal nerve than in intact ones. Neurography also showed abnormalities such as nerve indentation, swelling and running transversely in their course through the foramen. In all patients, leg pain was ameliorated after selective decompression (n = 9) or nerve block (n = 5). We demonstrated the first use of DWI and neurography of human lumbar nerves to visualize and quantitatively evaluate lumbar nerve entrapment with foraminal stenosis. We believe that DWI is a potential tool for diagnosis of lumbar nerve entrapment.

In this study, the nuclear medicine staff wore one finger dosimeter placed at the base of the index finger of the working hand. When a physician injected radioisotope drugs, the finger dose was 22.4 microSv, that for radiological technologists handling (99m)Tc was 29.6 microSv/day (consultation period 20 days), that for a physician injecting (18)F-FDG-PET drugs was 51.3 microSv (right finger 53.9 microSv, left finger 47.2 microSv), that for pharmacists' assay of FDG was 31.5 microSv, and that for radiological technologists positioning patients was 1.9 microSv. The largest value (94.1 microSv) was observed in physicians in the case of aspiration of a delivered drug. The finger dosimeter provides an effective solution for radiation protection procedures and follow-up. All the above staff members are on rotation and do not constantly handle radioactivity throughout the year.

A medical compact cyclotron produces about 10(15) neutrons per day along with 100 GBq of (18)F. Therefore, it is important to establish radiation safety guidelines on residual radioactivity for routine operation, maintenance work, and decommissioning. Thus, we developed a simple method for measuring the thermal neutrons in a cyclotron room. In order to verify the feasibility of our proposed method, we measured the thermal neutron distribution around a cyclotron by using the activation of (23)Na in salt. We installed 78 salt dosimeters in the cyclotron room with a 50 cm mesh. The photopeak of (24)Na was measured, and the neutron flux distribution was estimated. Monitoring the neutron flux distribution in a cyclotron room appears to be useful for not only obtaining an accurate estimate of the distribution of induced radioactivity, but also optimizing the shield design for radiation safety in preparation for the decommissioning process.

We have previously proposed an intersection profile method for reconstructing four-dimensional (4-D) magnetic resonance imaging (MRI) consisting of one breathing cycle of the thoracoabdominal region. This method captures a set of temporal sequence images in a proper sagittal plane and sets of temporal sequence images in continuous coronal slices. The former set is used as a navigator slice and the latter sets are used as data slices. A 4-D MRI is reconstructed by synchronizing the respiratory pattern found in the navigator slice and the data slices. We propose a prospective method to reduce the acquisition time for data slices. During data slice acquisition, the synchronization process between the respiratory pattern found in the navigator slice and one data slice is monitored in real time. Data acquisition will be terminated and moved to the next data slice based on a threshold value. We used 14 data sets (seven patients with certain pulmonary disease and seven healthy volunteers) previously obtained for the original intersection profile method for a simulation using the proposed method to evaluate the time reduction and impact on image quality. Each of the data set was tested using three different threshold values and the acquisition time can be reduced up to 75%. Although the quantitative evaluation of image quality was slightly worse than that by the conventional method, the difference based on the visual inspection was subtle to human eyes.

Introduction It is difficult to correctly diagnose lumbar degenerated disease with foraminal stenosis using conventional X-ray imaging, CT, and MRI. This difficulty can sometimes result in failed back syndrome. Diffusion Tensor Imaging (DTI) was reported as a potential tool for the diagnosis for foraminal stenosis. The purpose of this study is to evaluate the efficacy of DTI for diagnosis of degenerated lumbar disease. Materials and Methods Total 27 patients (20 men, mean age, 68.5 years) with degenerated lumbar disease who underwent 3.0 T MRI and surgical treatment were included. DTI (tractography), fractional anisotropy (FA), and improvement in Japanese Orthopaedic Association (JOA) and visual analog scale (VAS) pain score were investigated. Results The diagnoses by conventional imaging were lumbar spinal stenosis without foraminal stenosis in 11 cases, with foraminal stenosis in 10 cases, lumbar disk herniation in 3 cases, spondylolisthesis in 2 cases, and discogenic low back pain in 1 case. We classified the patients into following four groups by the shape of the tractography; disruption, narrowing, tapering, and no abnormalities. The mean preoperative JOA and VAS score were 14 and 88, and postoperative score were 21 and 12, respectively. The JOA score was improved by 46%. Tractography of the ipsilateral side showed disruption, narrowing, and tapering, and a lower FA compared with the contralateral side. There was no significant correlation between FA and symptoms. Conclusion Although there is no significant correlation between DTI and postsurgical symptoms, DTI has the possibility of detecting lesions of nerve damage, and to be a new diagnostic tool for the degenerated lumbar disease. I confirm having declared any potential conflict of interest for all authors listed on this abstract Yes Disclosure of Interest None declared