Search

Objective: Magnetic resonance imaging (MRI) is commonly used to evaluate cervical spinal canal stenosis; however, some patients are ineligible for MRI. We aimed to assess the effect of deep learning reconstruction (DLR) in evaluating cervical spinal canal stenosis using computed tomography (CT) compared with hybrid iterative reconstruction (hybrid IR)., Methods: This retrospective study included 33 patients (16 male patients; mean age, 57.7 ± 18.4 years) who underwent cervical spine CT. Images were reconstructed using DLR and hybrid IR. In the quantitative analyses, noise was recorded by placing the regions of interest on the trapezius muscle. In the qualitative analyses, 2 radiologists evaluated the depiction of structures, image noise, overall image quality, and degree of cervical canal stenosis. We additionally evaluated the agreement between MRI and CT in 15 patients for whom preoperative cervical MRI was available., Results: Image noise was less with DLR than hybrid IR in the quantitative ( P ≤ 0.0395) and subjective analyses ( P ≤ 0.0023), and the depiction of most structures was improved ( P ≤ 0.0052), which resulted in better overall quality ( P ≤ 0.0118). Interobserver agreement in the assessment of spinal canal stenosis with DLR (0.7390; 95% confidence interval [CI], 0.7189-0.7592) was superior to that with hybrid IR (0.7038; 96% CI, 0.6846-0.7229). As for the agreement between MRI and CT, significant improvement was observed for 1 reader with DLR (0.7910; 96% CI, 0.7762-0.8057) than hybrid IR (0.7536; 96% CI, 0.7383-0.7688)., Conclusions: Deep learning reconstruction provided better quality cervical spine CT images in the evaluation of cervical spinal stenosis than hybrid IR., Competing Interests: The authors declare no conflict of interest., (Copyright © 2023 Wolters Kluwer Health, Inc. All rights reserved.)

This study aims to assess the diagnostic value of virtual monochromatic image (VMI) at low keV energy for early detection of small hepatocellular carcinoma (HCC) in hepatic arterial phase compared with low-tube voltage (80 kVp) CT generated from dual-energy CT (DE-CT). A total of 107 patients with 114 hypervascular HCCs (≤2 cm) underwent DE-CT, 140 kVp, blended 120 kVp, and 80 kVp images were generated, as well as 40 and 50 keV. CT numbers of HCCs and the standard deviation as image noise on psoas muscle were measured. The contrast-to-noise ratios (CNR) of HCC were compared among all techniques. Overall image quality and sensitivity for detecting HCC hypervascularity were qualitatively assessed by three readers. The mean CT numbers, CNR, and image noise were highest at 40 keV followed by 50 keV, 80 kVp, blended 120 kVp, and 140 kVp. Significant differences were found in all evaluating endpoints except for mean image noise of 50 keV and 80 kVp. Image quality of 40 keV was the lowest, but still it was considered acceptable for diagnostic purposes. The mean sensitivity for detecting lesion hypervascularity with 40 keV (92%) and 50 keV (84%) was higher than those with 80 kVp (56%). Low keV energy images were superior to 80 kVp in detecting hypervascularization of early HCC., Competing Interests: The authors have no funding and conflicts of interest to disclose., (Copyright © 2023 the Author(s). Published by Wolters Kluwer Health, Inc.)

Objective: This study aimed to investigate the impact of deep-learning reconstruction (DLR) on the detailed evaluation of solitary lung nodule using high-resolution computed tomography (HRCT) compared with hybrid iterative reconstruction (hybrid IR)., Methods: This retrospective study was approved by our institutional review board and included 68 consecutive patients (mean ± SD age, 70.1 ± 12.0 years; 37 men and 31 women) who underwent computed tomography between November 2021 and February 2022. High-resolution computed tomography images with a targeted field of view of the unilateral lung were reconstructed using filtered back projection, hybrid IR, and DLR, which is commercially available. Objective image noise was measured by placing the regions of interest on the skeletal muscle and recording the SD of the computed tomography attenuation. Subjective image analyses were performed by 2 blinded radiologists taking into consideration the subjective noise, artifacts, depictions of small structures and nodule rims, and the overall image quality. In subjective analyses, filtered back projection images were used as controls. Data were compared between DLR and hybrid IR using the paired t test and Wilcoxon signed-rank sum test., Results: Objective image noise in DLR (32.7 ± 4.2) was significantly reduced compared with hybrid IR (35.3 ± 4.4) ( P < 0.0001). According to both readers, significant improvements in subjective image noise, artifacts, depictions of small structures and nodule rims, and overall image quality were observed in images derived from DLR compared with those from hybrid IR ( P < 0.0001 for all)., Conclusions: Deep-learning reconstruction provides a better high-resolution computed tomography image with improved quality compared with hybrid IR., Competing Interests: The authors declare no conflict of interest., (Copyright © 2023 Wolters Kluwer Health, Inc. All rights reserved.)

To compare the quality and interobserver agreement in the evaluation of lumbar spinal stenosis (LSS) on computed tomography (CT) images between deep-learning reconstruction (DLR) and hybrid iterative reconstruction (hybrid IR). This retrospective study included 30 patients (age, 71.5 ± 12.5 years; 20 men) who underwent unenhanced lumbar CT. Axial and sagittal CT images were reconstructed using hybrid IR and DLR. In the quantitative analysis, a radiologist placed regions of interest within the aorta and recorded the standard deviation of the CT attenuation (i.e., quantitative image noise). In the qualitative analysis, 2 other blinded radiologists evaluated the subjective image noise, depictions of structures, overall image quality, and degree of LSS. The quantitative image noise in DLR (14.8 ± 1.9/14.2 ± 1.8 in axial/sagittal images) was significantly lower than that in hybrid IR (21.4 ± 4.4/20.6 ± 4.0) (P < .0001 for both, paired t test). Subjective image noise, depictions of structures, and overall image quality were significantly better with DLR than with hybrid IR (P < .006, Wilcoxon signed-rank test). Interobserver agreements in the evaluation of LSS (with 95% confidence interval) were 0.732 (0.712-0.751) and 0.794 (0.781-0.807) for hybrid IR and DLR, respectively. DLR provided images with improved quality and higher interobserver agreement in the evaluation of LSS in lumbar CT than hybrid IR., Competing Interests: The authors have no conflicts of interest to disclose., (Copyright © 2023 the Author(s). Published by Wolters Kluwer Health, Inc.)

Objective: This study aimed to test the usefulness of computer-aided detection (CAD) for the detection of brain metastasis (BM) on contrast-enhanced computed tomography., Methods: The test data set included whole-brain axial contrast-enhanced computed tomography images of 25 cases with 62 BMs and 5 cases without BM. Six radiologists from 3 institutions with 2 to 4 years of experience independently reviewed the cases, both in conditions with and without CAD assistance. Sensitivity, positive predictive value, number of false positives, and reading time were compared between the conditions using paired t tests. Subanalysis was also performed for groups of lesions divided according to size. A P value <0.05 was considered statistically significant., Results: With CAD, sensitivity significantly increased from 80.4% to 83.9% ( P = 0.04), whereas positive predictive value significantly decreased from 88.7% to 84.8% ( P = 0.03). Reading time with and without CAD was 112 and 107 seconds, respectively ( P = 0.38), and the number of false positives was 10.5 with CAD and 7.0 without CAD ( P = 0.053). Sensitivity significantly improved for 6- to 12-mm lesions, from 71.2% without CAD to 80.3% with CAD ( P = 0.02). The sensitivity of the CAD (95.2%) was significantly higher than that of any reader (with CAD: P = 0.01; without CAD: P = 0.005)., Conclusions: Computer-aided detection significantly improved BM detection sensitivity without prolonging reading time while marginally increased the false positives., Competing Interests: The authors declare no conflict of interest., (Copyright © 2022 Wolters Kluwer Health, Inc. All rights reserved.)

Abstract: Although differentiating benign and malignant thymic epithelial lesions is important to avoid unnecessary treatment and predict prognosis, it is challenging because of overlaps in the chest computed tomography (CT) findings. In this study, we investigated whether the diameter of the thymic vein and other CT findings could differentiate between benign (thymoma and thymic cysts) and malignant (thymic carcinoma, [TCa]) lesions.We conducted a retrospective study across two tertiary referral hospitals in Japan between November 2009 and June 2018. We included 12 patients with TCa, 34 patients with thymomas, and 17 patients with thymic cysts. We analyzed the receiver operating characteristic (ROC) curve to determine the best cut-off values and performed univariate and multivariate analyses of CT findings to distinguish TCa from other benign lesions. Post-hoc analysis was performed for the maximum short axis of the thymic vein using the Mann-Whitney U test, and the number of the maximum short axis of the thymic vein ≥ the cutoff was determined using the Fisher exact test with a family-wise error-correction using Bonferroni's method.ROC analysis showed that a maximum short axis of the thymic vein ≥2 mm was considerably more frequent in TCa than in the other lesions (P < .001 for both), with 83% sensitivity and 86% specificity. Univariate and multivariate analyses revealed the association with TCa of the number of the maximum short axis of the thymic vein ≥2 mm (P = .005, multivariate generalized linear model analysis), ill-defined margin (P = .001), and mediastinal lymphadenopathy (P < .001). Thymic vein diameter was in descendimg order of TCa > thymoma > thymic cysts with statistically significant differences between the groups (Ps < .05).Thymic vein diameter was significantly longer in TCa than in thymoma and thymic cysts. Measurement of the maximum short axis of the thymic vein could be a powerful diagnostic tool to differentiate TCa from thymoma and thymic cysts., Competing Interests: The authors have no funding and conflicts of interests to disclose., (Copyright © 2021 the Author(s). Published by Wolters Kluwer Health, Inc.)

Abstract: In this single-center retrospective study, we intended to evaluate the frequencies and characteristics of computed tomography findings of pancreatobiliary inflammation (PBI) in patients treated with lenvatinib and the relationship of these findings with treatment-planning changes.We included 78 patients (mean ± standard deviation, 69.8 ± 9.4 years, range: 39-84 years, 62 men) with hepatocellular carcinoma (n = 62) or thyroid carcinoma (n = 16) who received lenvatinib (June 2016-September 2020). Two radiologists interpreted the posttreatment computed tomography images and assessed the radiological findings of PBI (symptomatic pancreatitis, cholecystitis, or cholangitis). The PBI effect on treatment was statistically evaluated.PBI (pancreatitis, n = 1; cholecystitis, n = 7; and cholangitis, n = 2) was diagnosed in 11.5% (9/78) of the patients at a median of 35 days after treatment initiation; 6 of 9 patients discontinued treatment because of PBI. Three cases of cholecystitis and 1 of cholangitis were accompanied by gallstones, while the other 5 were acalculous. The treatment duration was significantly shorter in patients with PBI than in those without (median: 44 days vs. 201 days, P = .02). Overall, 9 of 69 patients without PBI showed asymptomatic gallbladder subserosal edema.Lenvatinib-induced PBI developed in 11.5% of patients, leading to a significantly shorter treatment duration. Approximately 55.6% of the PBI cases were acalculous. The recognition of this phenomenon would aid physicians during treatment planning in the future., Competing Interests: The authors have no funding and conflicts of interest to disclose., (Copyright © 2021 the Author(s). Published by Wolters Kluwer Health, Inc.)

Abstract: To evaluate the rib fracture detection performance in computed tomography (CT) images using a software based on a deep convolutional neural network (DCNN) and compare it with the rib fracture diagnostic performance of doctors.We included CT images from 39 patients with thoracic injuries who underwent CT scans. In these images, 256 rib fractures were detected by two radiologists. This result was defined as the gold standard. The performances of rib fracture detection by the software and two interns were compared via the McNemar test and the jackknife alternative free-response receiver operating characteristic (JAFROC) analysis.The sensitivity of the DCNN software was significantly higher than those of both Intern A (0.645 vs 0.313; P < .001) and Intern B (0.645 vs 0.258; P < .001). Based on the JAFROC analysis, the differences in the figure-of-merits between the results obtained via the DCNN software and those by Interns A and B were 0.057 (95% confidence interval: -0.081, 0.195) and 0.071 (-0.082, 0.224), respectively. As the non-inferiority margin was set to -0.10, the DCNN software is non-inferior to the rib fracture detection performed by both interns.In the detection of rib fractures, detection by the DCNN software could be an alternative to the interpretation performed by doctors who do not have intensive training experience in image interpretation., Competing Interests: The authors have no funding and conflicts of interest to disclose., (Copyright © 2021 the Author(s). Published by Wolters Kluwer Health, Inc.)

Objectives: The aims of this study were to develop an accelerated multiparametric magnetic resonance imaging method based on 3D-quantification using an interleaved Look-Locker acquisition sequence with a T2 preparation pulse (3D-QALAS) combined with compressed sensing (CS) and to evaluate the effect of CS on the quantitative mapping, tissue segmentation, and quality of synthetic images., Materials and Methods: A magnetic resonance imaging system phantom, containing multiple compartments with standardized T1, T2, and proton density (PD) values; 10 healthy volunteers; and 12 patients with multiple sclerosis were scanned using the 3D-QALAS sequence with and without CS and conventional contrast-weighted imaging. The scan times of 3D-QALAS with and without CS were 5:56 and 11:11, respectively. For healthy volunteers, brain volumetry and myelin estimation were performed based on the measured T1, T2, and PD. For patients with multiple sclerosis, the mean T1, T2, PD, and the amount of myelin in plaques and contralateral normal-appearing white matter (NAWM) were measured. Simple linear regression analysis and Bland-Altman analysis were performed for each metric obtained from the datasets with and without CS. To compare overall image quality and structural delineations on synthetic and conventional contrast-weighted images, case-control randomized reading sessions were performed by 2 neuroradiologists in a blinded manner., Results: The linearity of both phantom and volunteer measurements in T1, T2, and PD values obtained with and without CS was very strong (R2 = 0.9901-1.000). The tissue segmentation obtained with and without CS also had high linearity (R2 = 0.987-0.999). The quantitative tissue values of the plaques and NAWM obtained with CS showed high linearity with those without CS (R2 = 0.967-1.000). There were no significant differences in overall image quality between synthetic contrast-weighted images obtained with and without CS (P = 0.17-0.99)., Conclusions: Multiparametric imaging of the whole brain based on 3D-QALAS can be accelerated using CS while preserving tissue quantitative values, tissue segmentation, and quality of synthetic images., Competing Interests: Conflicts of interest and sources of funding: N.T. is an employee of GE Healthcare Japan. This work was supported by Japan Agency for Medical Research and Development under grant number JP19lk1010025h9902; JSPS KAKENHI grant numbers 19K17150, 19K17177, 18H02772, and 18K07692; Health, Labor and Welfare Policy Research Grants for Research on Region Medical; and a grant-in-aid for special research in subsidies for ordinary expenses of private schools from The Promotion and Mutual Aid Corporation for Private Schools of Japan; Brain/MINDS beyond program from Japan Agency for Medical Research and Development grant numbers JP19dm0307024 and JP19dm0307101., (Copyright © 2020 The Author(s). Published by Wolters Kluwer Health, Inc.)

Objective: Identify appropriate reconstruction modes of Forward-projected model-based Iterative Reconstruction SoluTion (FIRST) in temporal bone computed tomography (CT) and investigate the contribution of spatial resolution and noise to the visual assessment., Methods: Sixteen temporal bone CT images were reconstructed. Two blinded radiologists assessed 8 anatomical structures and classified the visual assessment. These visual scores were compared across reconstruction modes among each anatomical structure. Visual scores and contrast-to-noise ratio, noise power spectrum (NPS) at low (NPSLow) and high (NPSHigh) spatial frequencies, and 50% modulation transfer function relationships were evaluated., Results: Visual scores differed significantly for the stapedius muscle and osseous spiral lamina, with CARDIAC SHARP, BONE, and LUNG modes for the osseous spiral lamina scoring highest. Visual scores significantly positively correlated with NPSLow, NPSHigh, and 50% modulation transfer function but negatively with contrast-to-noise ratio., Conclusions: Modes providing higher spatial resolution and lower noise reduction showed an improved visual assessment of CT images reconstructed with FIRST., Competing Interests: This is a collaborative research with Canon Medical Systems Corporation. S.T. and R.T. are employees of Canon Medical Systems Corporation. E.M. and O.A. received honoraria (eg, lecture fee) and research funding from Canon Medical Systems Corporation. J.S. receives research funding from Canon Medical Systems Corporation. All other authors declare no conflict of interest., (Copyright © 2020 Wolters Kluwer Health, Inc. All rights reserved.)

To evaluate the utility of unenhanced postmortem computed tomography (PMCT) for the investigation of in-hospital nontraumatic death in children up to 3 years of age.This study included the cadavers of children who died from intrinsic diseases before 3 years of age. The major underlying disease and the main organ-disease systems associated with the immediate causes of death were determined by clinical evaluation, PMCT, and autopsy, which were used as a reference standard. The rates of concordance between the former two methods and autopsy were calculated for all cases.In total, 22 cadavers (12 male and 10 female; mean age, 6.1 ± 8.2 months) were included. The rates of concordance between clinical evaluation/PMCT and autopsy for diagnosis of the major underlying disease and main organ-disease systems associated with the immediate causes of death were 100%/36% (P = .0015) and 59%/41% (P = .37), respectively. In cases where the respiratory system was associated with the immediate cause of death, PMCT showed greater diagnostic sensitivity (90%) than did clinical evaluation (20%). In contrast, the diagnostic sensitivity of PMCT was lower than that of clinical evaluation in cases involving disorders of the cardiac system and multiple organ systems (0% vs 100% for both).The findings of this study suggest that the use of unenhanced PMCT with clinical evaluation can result in improved detection of the immediate cause of death in select cases of in-hospital nontraumatic death before 3 years of age.

Objectives: Quantitative synthetic magnetic resonance imaging (MRI) enables synthesis of various contrast-weighted images as well as simultaneous quantification of T1 and T2 relaxation times and proton density. However, to date, it has been challenging to generate magnetic resonance angiography (MRA) images with synthetic MRI. The purpose of this study was to develop a deep learning algorithm to generate MRA images based on 3D synthetic MRI raw data., Materials and Methods: Eleven healthy volunteers and 4 patients with intracranial aneurysms were included in this study. All participants underwent a time-of-flight (TOF) MRA sequence and a 3D-QALAS synthetic MRI sequence. The 3D-QALAS sequence acquires 5 raw images, which were used as the input for a deep learning network. The input was converted to its corresponding MRA images by a combination of a single-convolution and a U-net model with a 5-fold cross-validation, which were then compared with a simple linear combination model. Image quality was evaluated by calculating the peak signal-to-noise ratio (PSNR), structural similarity index measurements (SSIMs), and high frequency error norm (HFEN). These calculations were performed for deep learning MRA (DL-MRA) and linear combination MRA (linear-MR), relative to TOF-MRA, and compared with each other using a nonparametric Wilcoxon signed-rank test. Overall image quality and branch visualization, each scored on a 5-point Likert scale, were blindly and independently rated by 2 board-certified radiologists., Results: Deep learning MRA was successfully obtained in all subjects. The mean PSNR, SSIM, and HFEN of the DL-MRA were significantly higher, higher, and lower, respectively, than those of the linear-MRA (PSNR, 35.3 ± 0.5 vs 34.0 ± 0.5, P < 0.001; SSIM, 0.93 ± 0.02 vs 0.82 ± 0.02, P < 0.001; HFEN, 0.61 ± 0.08 vs 0.86 ± 0.05, P < 0.001). The overall image quality of the DL-MRA was comparable to that of TOF-MRA (4.2 ± 0.7 vs 4.4 ± 0.7, P = 0.99), and both types of images were superior to that of linear-MRA (1.5 ± 0.6, for both P < 0.001). No significant differences were identified between DL-MRA and TOF-MRA in the branch visibility of intracranial arteries, except for ophthalmic artery (1.2 ± 0.5 vs 2.3 ± 1.2, P < 0.001)., Conclusions: Magnetic resonance angiography generated by deep learning from 3D synthetic MRI data visualized major intracranial arteries as effectively as TOF-MRA, with inherently aligned quantitative maps and multiple contrast-weighted images. Our proposed algorithm may be useful as a screening tool for intracranial aneurysms without requiring additional scanning time.

Rationale: Budd-Chiari syndrome (BCS), which causes congestive hepatopathy and aggravates cirrhosis, is typically treated by interventional angioplasty to ameliorate blood flow. X-ray venography is useful for the evaluation of inferior vena cava (IVC) stenosis and determination of treatment timing, but it is invasive and thus unsuitable for repeated examinations. The development of a simple method for the prediction of IVC stenosis would reduce the burden on patients with BCS., Patient Concerns: We report here our experience of 2 patients with BCS who underwent percutaneous transluminal angioplasty (PTA). The first patient was a 39-year-old male who underwent PTA to expand his stenotic IVC. The second patient was a 19-year-old male who underwent PTA 3 times due to restenosis of his IVC., Diagnoses: Both patients were diagnosed with BCS with severe obstruction of the IVC., Interventions: We evaluated the hepatic vein (HV) waveform by Doppler ultrasonography and measured liver stiffness (LS) using transient elastography (TE) before and after PTA., Outcomes: In case 1, the phasic oscillation of the HV waveform recovered and the LS value decreased after PTA. Both improvements were maintained for ∼3 years, reflecting the long-term patency of the IVC. In case 2, the HV waveform and the LS value improved temporarily after PTA, but then deteriorated gradually. Monitoring of the HV waveform and LS value allowed retreatment prior to total occlusion of the IVC and abrogated the risk of intravascular needle puncture., Lessons: Monitoring of the HV waveform and the LS value enables safe management of patients with BCS who may require PTA.

Little is known regarding differences between model-based iterative reconstruction (MBIR) and hybrid iterative reconstruction (HIR) in temporal bone computed tomography (CT). This study compared the ability to depict microstructures in temporal bone in quarter-detector CT (QDCT) between MBIR and HIR.Sixty-two temporal bones in 31 consecutive adult patients who underwent QDCT were included. Reconstruction was performed with Forward projected model-based Iterative Reconstruction SoluTion (FIRST) BONE mild mode and Adaptive Iterative Dose Reduction 3D (AIDR3D) enhanced mild mode. Imaging quality was graded for 3 microstructures (spiral osseous lamina, tympanic membrane, and singular canal).Spiral osseous lamina was significantly well-delineated in the AIDR3D enhanced group, compared with the FIRST group. In nearly all cases with FIRST, spiral osseous lamina was poorly defined. Although there was no significant difference, depiction of the tympanic membrane and singular canal tended to be better with AIDR3D enhanced mode.Routine reconstruction for preoperative temporal bone CT should be performed with HIR, rather than MBIR.

To compare coronary artery luminal enhancement in coronary computed tomography angiography (CCTA) between ventral and dorsal region-of-interest (ROI) bolus tracking in the descending aorta.The records of 165 consecutive patients who underwent CCTA with non-helical acquisition from July 2017 to March 2018 were retrospectively examined. We performed 320-row CCTA with bolus tracking [scan triggered at 260 HU in the descending aorta] and 133 patients were finally included. ROI was set in the ventral and dorsal halves of the descending aorta in 68 and 65 patients, respectively.Contrast arrival time was significantly shorter in the dorsal group (ventral: 21.8 ± 0.372 s; dorsal: 20.7 ± 0.369; P = .0295). The mean density of the proximal and distal RCA was significantly higher in the ventral group (proximal: ventral, 428.1 ± 6.95 HU; dorsal, 405.5 ± 7.72 HU, P = .0318; distal: ventral, 418.0 ± 9.29 HU; dorsal, 393.2 ± 9.46 HU, P = .0133).Dorsal bolus tracking ROI in the descending thoracic aorta significantly reduced preparation time and RCA CT values.

Objectives: The aim of this study was to evaluate the linearity, bias, intrascanner repeatability, and interscanner reproducibility of quantitative values derived from a multidynamic multiecho (MDME) sequence for rapid simultaneous relaxometry., Materials and Methods: The NIST/ISMRM (National Institute of Standards and Technology/International Society for Magnetic Resonance in Medicine) phantom, containing spheres with standardized T1 and T2 relaxation times and proton density (PD), and 10 healthy volunteers, were scanned 10 times on different days and 2 times during the same session, using the MDME sequence, on three 3 T scanners from different vendors. For healthy volunteers, brain volumetry and myelin estimation were performed based on the measured T1, T2, and PD. The measured phantom values were compared with reference values; volunteer values were compared with their averages across 3 scanners., Results: The linearity of both phantom and volunteer measurements in T1, T2, and PD values was very strong (R = 0.973-1.000, 0.979-1.000, and 0.982-0.999, respectively) The highest intrascanner coefficients of variation (CVs) for T1, T2, and PD were 2.07%, 7.60%, and 12.86% for phantom data, and 1.33%, 0.89%, and 0.77% for volunteer data, respectively. The highest interscanner CVs of T1, T2, and PD were 10.86%, 15.27%, and 9.95% for phantom data, and 3.15%, 5.76%, and 3.21% for volunteer data, respectively. Variation of T1 and T2 tended to be larger at higher values outside the range of those typically observed in brain tissue. The highest intrascanner and interscanner CVs for brain tissue volumetry were 2.50% and 5.74%, respectively, for cerebrospinal fluid., Conclusions: Quantitative values derived from the MDME sequence are overall robust for brain relaxometry and volumetry on 3 T scanners from different vendors. Caution is warranted when applying MDME sequence on anatomies with relaxometry values outside the range of those typically observed in brain tissue.

Objectives: The aim of this study was to compare accuracy of measurement between virtual monochromatic imaging (VMI) in dual-energy computed tomography and conventional polychromatic 120-kVp computed tomographic scan in vascular models containing various densities of contrast material., Methods: We evaluated measured diameters of 12 models of vessels of 4 inner diameters containing high, intermediate, and low densities of contrast material using software automation., Results: Measurement errors with 70-keV VMI were significantly larger than or comparable to errors with 120-kVp scan for all models, and those with 50-keV VMI were significantly smaller than errors with 120-kVp scan for low-density models and larger for high-density models., Conclusions: Acquisition of images by VMI at low energy facilitates accurate measurement of diameters of poorly enhanced vessels with reduced iodine load but can increase measurement errors in other situations by decreasing spatial resolution, so VMI should be applied carefully to evaluate vessel diameter.

We sought to evaluate clinical outcomes and toxicities of radiation therapy (RT) alone compared to RT with concurrent chemotherapy (CCT) for nasopharyngeal carcinoma (NPC) treatment.We conducted a retrospective review of consecutive patients with biopsy-proven nonmetastatic NPC who underwent RT at our institution. From May 2001 to April 2015; 62 newly diagnosed NPC patients were treated with three-dimensional conformal radiotherapy (3D-CRT) or intensity-modulated radiotherapy (IMRT) with or without CCT. The patients were classified as follows: 8% stage I, 15% stage II, 32% stage III, and 45% stage IVA/IVB. A total of 76% of tumors were World Health Organization types II or III. Acute and late toxicities were graded according to the Common Terminology Criteria for Adverse Events version 3.0. Overall survival (OS), progression-free survival (PFS), locoregional progression-free survival (LRPFS), and distant metastasis-free survival (DMFS) were analyzed.The median follow-up period for living patients was 53 months. The median actual delivered dose was 70 Gy with a range of 28 to 70 Gy in fraction sizes of 2 Gy. The estimated 5-year OS, PFS, LRPFS, and DMFS rates were 72.7%, 59.8%, 77.9%, and 84.2%, respectively. The use of CCT was a predictive factor of significantly better OS and PFS, whereas stage IV was a significant predictor of poor OS and PFS. The most severe acute toxicities included Grade 3 mucositis in 56% and Grade 3 dermatitis in 8%. Subset analysis revealed that Grade 2 xerostomia was significantly lower in the IMRT (23%) group than in the 3D-CRT (52%) group (P = .02).RT yielded favorable outcomes. CCT was associated with longer PFS and OS than RT alone.

Objective: The aim of this study was to investigate the effects of single-scan and scan-pair intensity inhomogeneity correction methods on the repeatability of voxel-based morphometry (VBM) using images acquired with multiple magnetic resonance (MR) scanners., Methods: Three-dimensional T1-weighed MR images of the brain were obtained from 22 healthy participants using each of 5 MR scanners, yielding 110 images (5 scanners × 22 subjects) in total. Six patterns of intensity inhomogeneity corrections (no correction, single-scan corrections, and scan-pair correction, and their combinations) were applied in the VBM procedure to investigate the effect of the corrections on the repeatability of gray and white matter volume measurements., Results: Single-scan and scan-pair intensity inhomogeneity corrections significantly reduced the variance in spatially normalized gray and white matter volumes. However, combining the 2 methods did not significantly improve the repeatability when evaluated as whole brain., Conclusions: Single-scan and scan-pair intensity inhomogeneity corrections improved the repeatability of gray and white matter volumes obtained by multiple MR scanners and assessed by VBM.

Although delayed-time-point imaging is expected to improve the results of [F]-fluorodeoxyglucose (FDG)-positron emission tomography/computed tomography (PET/CT), how examinees will benefit from dual-time-point imaging versus initial-time-point imaging alone, remains unclear. This study investigated the role of delayed-time-point imaging in improving the results of abdominal and pelvic cancer screening using FDG-PET/CT.This retrospective review included 3131 screening results (average subject age: 55.5 years, range: 40-88 years). First, 2 nuclear medicine physicians tentatively evaluated whole-body initial-time-point PET/CT scans. Subsequently, delayed-time-point imaging of the abdomen and pelvis was performed approximately 150 min after FDG injection, followed by re-evaluation for necessary changes. All changed records were retrospectively reviewed and classified as either lesions that were found in initial-time-point images but were changed into negative by adding delayed scan or newly detected findings of suspected malignancy on delayed-time-point images; lesions suspected to be malignant were subjected to further pathologic review. Diagnostic performance according to sensitivity, specificity, accuracy, positive predictive value (PPV), and negative predictive value (NPV) were calculated and compared between initial-time-point and dual-time-point imaging.Fifty-four records were changed after addition of the delayed-time-point imaging. Of the 105 suspected malignancies on initial-time-point images, 10 were changed into negative following the delayed scan. In addition, 44 lesions were newly detected as suspected malignancies on delayed-time-point images. Thirty-six lesions were proven to be pathologically malignant. Of these, 26 were detected on initial-time-point images, and 8 lesions (gastrointestinal adenocarcinoma, 6; prostate adenocarcinoma, 2) were observed on delayed-time-point images. The sensitivity of dual-time-point imaging (58.6% [34/58]) was significantly higher than that of initial-time-point imaging only (44.8% [26/58]) (P = .005); however, specificity and accuracy of dual-time-point imaging (96.6% [2968/3073] and 95.9% [3002/3131], respectively) were significantly lower than those of initial-time-point imaging only (97.4% [2994/3073] and 96.5% [3020/3131], respectively) (P < .0001 and P = .013, respectively). There were no significant differences in PPV (initial-time-point imaging: 24.8% [26/105], dual-time-point imaging: 24.5% [34/139]) and NPV (98.9% [2994/3026] and 99.2% [2968/3073], respectively).The inclusion of delayed PET/CT in screening examinations facilitated the detection of pathologically malignant lesions, particularly in the gastrointestinal tract, while also detecting benign and false-negative lesions.

Conventional magnetic resonance images are usually evaluated using the image signal contrast between tissues and not based on their absolute signal intensities. Quantification of tissue parameters, such as relaxation rates and proton density, would provide an absolute scale; however, these methods have mainly been performed in a research setting. The development of rapid quantification, with scan times in the order of 6 minutes for full head coverage, has provided the prerequisites for clinical use. The aim of this review article was to introduce a specific quantification method and synthesis of contrast-weighted images based on the acquired absolute values, and to present automatic segmentation of brain tissues and measurement of myelin based on the quantitative values, along with application of these techniques to various brain diseases. The entire technique is referred to as "SyMRI" in this review. SyMRI has shown promising results in previous studies when used for multiple sclerosis, brain metastases, Sturge-Weber syndrome, idiopathic normal pressure hydrocephalus, meningitis, and postmortem imaging.

Total body irradiation is performed as a preconditioning regimen to inhibit graft-versus-host disease after bone marrow transplantation and to eradicate remaining tumor cells. However, these regimens result in delayed secondary sex characteristics and failure of ovarian function recovery, leading to amenorrhea and infertility. Herein, we report a case of an 11-year-old girl diagnosed with acute lymphocytic leukemia who received induction chemotherapy and prophylactic cranial irradiation. For bone marrow transplantation, she received total body irradiation of 12 Gy with uterine and ovarian shielding at 13 years of age. The patient remained in remission and menarche began at 14 years of age. At 23, she became pregnant and delivered a baby naturally with no abnormalities.

Objective: Magnetic resonance imaging (MRI) is the most popular follow-up study for patients who have undergone spinal surgery. However, the image quality often becomes poor because of artifacts from metal implants and/or from failed fat suppression, which obscure diagnosis. Iterative decomposition of water and fat with echo asymmetry and least-squares estimation (IDEAL) is a new fat suppression method that is less affected by inhomogeneity of the magnetic field. Here, we compared postsurgical spinal MRI with IDEAL versus chemical shift selective saturation (CHESS)., Methods: For 35 patients who had spinal surgery, we examined T2-weighted fast spin-echo sagittal images of the spine with both IDEAL and CHESS. Two radiologists evaluated the degrees of fat suppression and spinal canal projection from 0 (least/worst) to 2 (most/best)., Results: Fat suppression and spinal canal scores for IDEAL were statistically higher than those for CHESS (P < 0.05)., Conclusions: Iterative decomposition of water and fat with echo asymmetry and least-squares estimation is clinically useful for postoperative spinal MRI.

Purpose: To investigate the feasibility of dynamic susceptibility-weighted contrast material-enhanced (DSC) perfusion imaging with ferucarbotran at 3.0 T, and to assess the impact of the different characteristics of gadolinium (Gd)- and ferucarbotran-based agent in rCBV measurement under pathologic condition with BBB disruption., Materials and Methods: Nine patients with suspected meningioma (4 men and 5 women; age range, 27-79 years; mean age, 61.6 +/- 17.9 years) were eligible for the study. Approval was obtained from the institutional review board. All participants provided signed informed consent prior to the study. DSC perfusion images were acquired with a T2*-weighted echo-planar imaging sequence during the first pass of a standard-dose of Gd-based agent, and of 4, 8, or 16 micromol Fe/kg of ferucarbotran-based agent in 3 patients for each dose respectively. Pre- and postenhanced T1-weighted images were obtained in all., Results: Ferucarbotran decreased the signal intensity in both gray and white matter in a dose-dependent fashion. Differences regarding the DeltaSI between the 4 and 8 or 8 and 16 micromol Fe/kg groups were statistically significant (P < 0.05, 1-way analysis of variance, Tukey-Kramer method) in any region. No effect of leakage of ferucarbotran was demonstrated in the intensity-time curves or in the postenhanced T1-weighted images. Relative CBV in tumor area obtained with Gd was reduced to 37.6%-86.5% compared with that obtained with ferucarbotran., Conclusions: T2*-weighted DSC perfusion imaging with ferucarbotran is feasible at 3.0 T. Compared with Gd-based agent, larger particle size of ferucarbotran can diminish the effect of contrast leakage during the first pass under pathologic conditions with BBB disruption.

We report a patient with linear scleroderma en coup de sabre without neurological symptoms despite the presence of large white matter lesions. The patient underwent 3.0-T magnetic resonance (MR) examinations including diffusion tensor imaging, time-resolved contrast-enhanced MR angiography, susceptibility-weighted imaging, and proton MR spectroscopy. These imaging findings suggested increased vascular permeability and microbleeding without abnormalities of metabolites. Our observation is consistent with vasculopathy and may be helpful in the proper diagnosis and treatment of linear scleroderma en coup de sabre.

Objective: To assess corticospinal tract involvement in patients with amyotrophic lateral sclerosis (ALS) by correlating diffusion tensor imaging (DTI) measures with intra- and extracranial central motor conduction time (CMCT) and clinical features of the patients., Methods: We investigated 31 patients with ALS and 31 normal volunteers by DTI and measured fractional anisotropy (FA) within the corticospinal tracts and in the extramotor white matter. We measured CMCT for the first dorsal interosseous muscle and segmented it into cortical-brainstem (CTX-BS CT) and brainstem-cervical root (BS-CV CT) conduction times by magnetic brainstem stimulation at the foramen magnum level. Clinical status of each patient was evaluated with the ALS Functional Rating Scale-Revised (ALSFRS-R) and upper motor neuron (UMN) score devised for this study., Results: We found a significant decrease of mean FA in all regions of the corticospinal tracts in patients with ALS as compared with controls. We found that FA along the corticospinal tract decreased significantly with higher UMN scores. There was no significant correlation between FA and ALSFRS-R, to which both upper and lower motoneuron involvements contribute. FA showed a significant correlation with the intracranial part of the central motor conduction (CTX-BS CT) but not with the extracranial conduction time., Conclusions: Fractional anisotropy reflects functional abnormality of intracranial corticospinal tracts and can be used for objective evaluation of upper motor neuron impairment in amyotrophic lateral sclerosis.

Objective: To visualize the corticospinal tract (CST) in patients with arteriovenous malformations (AVMs) by using diffusion tensor tractography (DTT) and to confirm the clinical reliability of DTT in patients with AVMs., Methods: We performed DTT in 24 patients who had their AVMs near the CST. Tracts and AVMs were shown simultaneously, providing information on their spatial relationships. We also counted numbers of voxels in the DTT-CST at the level of the AVM., Results: DTT was visualized in 23 patients. In all 9 patients with hemiparesis, their DTT-CSTs were involved in the AVM or its surrounding lesion. Their volume of DTT-CST at the affected side was significantly decreased when compared with the contralateral side (P = 0.0469). All 14 patients whose DTT-CSTs were free from lesion had no hemiparesis., Conclusions: DTT was safe and clinically applicable in patients with AVMs. DTT is recommended when an AVM is located near the corticospinal tract.

Objective: To evaluate diffusion tensor imaging (DTI) based on periodically rotated overlapping parallel lines with enhanced reconstruction (PROPELLER) compared with DTI based on single-shot echo planar imaging (EPI)., Methods: Diffusion tensor data were acquired with PROPELLER (PROPELLER-DTI, 3 NEX), EPI (EPI-DTI2, 16 NEX) with the same acquisition time (11.4 minutes) and with EPI (EPI-DTI1, number of excitations = 4) with a shorter acquisition time (2.8 minutes). Regions of interest were set in the genu and splenium of the corpus callosum, as determined on T2-weighted fast spin echo images and fractional anisotropy (FA) maps, separately. Two neuroradiologists visually evaluated image distortion and quality in the supra- and infratentorial structures., Results: In the genu, standard deviation determined by respective FA maps was decreased in order of PROPELLER-DTI, EPI-DTI1, and EPI-DTI2. Both EPI-DTI sequences were quantitatively superior in the splenium, but PROPELLER-DTI was less distorted., Conclusion: Periodically rotated overlapping parallel lines with enhanced reconstruction-DTI could become a complementary tool when qualitatively evaluating seriously distorted structures.

Objective: To evaluate the crossing fiber trajectory through the corpus callosum using distortion-corrected diffusion tensor tractography in the human brain., Methods: After correcting distortion associated with large-diffusion gradients, T2-weighted echo planar images (EPIs) acquired from 10 right-handed healthy men were coregistered into T2-weighted fast spin echo images using linear through sixth-order nonlinear, 3-dimensional, polynomial warping functions. The optimal transformation parameters were also applied to the distortion-corrected diffusion-weighted EPIs. Diffusion tensor tractography through the corpus callosum was reconstructed, employing the "1 or 2 regions of interest" method., Results: Compared with the lines through the genu, those through the rostrum ran more inferiorly and seemed to enter the orbital gyrus. Those lines entering posterior temporal white matter (tapetum) crossed through the ventral portion of the splenium and were clearly distinguished from lines that reached parieto-occipital white matter (forceps major)., Conclusion: Diffusion tensor tractography is a feasible noninvasive tool to evaluate commissural fiber trajectory.

Schizophrenic and normal control subjects were examined using both H-magnetic resonance spectroscopy (MRS) and structural MR imaging, in order to accurately assess the partial volume within the spectroscopic volume of interest (VOI) in the anterior cingulate cortex. The gray matter volume within VOI correlated positively with the N-acetyl-aspartate (NAA) to choline (Cho) ratio in schizophrenics only, not in controls. Schizophrenic patients had a reduced NAA/Cho ratio and an elevated Cho/creatine ratio compared to controls after the partial volume effect was eliminated. There was a significant negative correlation between the NAA/Cho ratio and the severity of blunted affect symptom in schizophrenics. These results provide further support to the idea that the measures of H-MRS indicate not only neuronal loss but also neuronal dysfunction in schizophrenia.

Though diffusion-weighted MRI has been applied to various intracranial lesions, few reports had been presented about cerebral hamartomatous lesions in patients with neurofibromatosis type 1 (NF1). In this study, we report the interval changes of apparent diffusion coefficient (ADC) in a presumed hamartomatous lesion. In our case, the ADC increased slightly over a 3 year period. This diffusion property may provide specific insight into the etiology of cerebral hamartomatous lesions observed in NF1.

Selective neuronal death of the hippocampal CA1 area after mild ischemia is known as delayed neuronal death (DND). Progression of DND was evaluated using 7T MRI in gerbils. In the CA1, the T2 relaxation time started to increase on day 3 and was significantly higher on day 4 than that of the control gerbils. However, the apparent diffusion coefficient of water (ADC) was significantly lower on day 1 than in the control and continued to decline up to day 4. Changes in T2 coincided with loss of MAP2 immunoreactivity, while the ADC decrease preceded these changes. After 1 month, the ADC had returned to within the normal range, while T2 had decreased to below the control level. These results suggest that MRI is useful for monitoring DND.

Droloxifene, a new tamoxifen (TAM)-derived compound, has excellent antiestrogenic activity. This compound exhibits less endogenously estrogenic but higher antiestrogenic activity, with better tolerability than TAM in experimental models. Two phase II studies of droloxifene were performed in 47 Japanese institutions to assess the optimal dose. The first was a randomized comparative study using 20, 40, and 80 mg, respectively, once a day. The other was a pilot study using 120 mg once a day. The subjects of both studies were women with primary or recurrent advanced breast cancer, regardless of estrogen receptor status and menopausal status. Of 94 patients enrolled in the comparative study, 22, 26, and 23 were evaluable in the 20-, 40-, and 80-mg groups, respectively. Of the 71 evaluable patients, 14 (19.7%) were negative for estrogen receptor, and 36 (50.7%) had a previous history of TAM therapy. The response rate complete response + partial response (CR + PR) was 13.6% for 20 mg, 15.4% for 40 mg, and 17.4% for 80 mg. The rate of no change (NC) was 31.9%, 46.1%, and 47.8%, and that of progressive disease (PD) was 54.5%, 38.5% and 34.8%, respectively, in the 20-, 40-, and 80-mg groups. In the other study, 16 patients were enrolled in the pilot study with 120 mg of droloxifene, of whom 14 were evaluable. The response rate was slightly higher: four responders (28.6%) were assessed as CR + PR, six (42.9%) as NC, and four (28.6%) as PD. These results suggest that the response rate may be dose-dependent and that PD rates seem lower in the higher doses. No serious side effects were encountered, and droloxifene was well tolerated even in the higher doses. At present, a final randomized dose-finding study with 80 mg/day and 120 mg/day is being carried out.

The efficacy and toxicity of (2''R)-4'-O-tetrahydropyranyl adriamycin (THP) were assessed in the treatment of patients with advanced breast cancer by the Japan THP Study Group. Mean plasma levels of THP after single-dose administration revealed triexponential decay characterized by an initial half-life of 0.89 h. A higher concentration of THP was obtained in the metastatic lymph nodes than in the breast cancer tissue at 4 h after administration (4.01 vs. 1.17 micrograms/g). Whereas 1 complete (CR) and 12 partial response (PR) were observed in 56 evaluable patients after administration of THP alone (23.2%), 1 CR and 12 PR were observed in 37 evaluable patients who had combination therapy including THP (35.1%). Multivariate analysis of prognostic factor revealed that the site of metastases had the most valuable prognostic significance; second was irradiation in the previous treatment, and third was the disease-free interval. Life-table analysis adjusted with the Cox proportional hazard model revealed a similar survival curve of patients receiving THP-cyclophosphamide, adriamycin, and 5-fluorouracil (CAF) to that of those receiving CAF only in spite of the low incidence of toxicity in the THP therapy.