小澤 良之

OBJECTIVE: To directly compare coronary arterial stenosis evaluations by hybrid-type iterative reconstruction (IR), model-based IR (MBIR), deep learning reconstruction (DLR), and high-resolution deep learning reconstruction (HR-DLR) on coronary computed tomography angiography (CCTA) in both in vitro and in vivo studies. MATERIALS AND METHODS: For the in vitro study, a total of three-vessel tube phantoms with diameters of 3 mm, 4 mm, and 5 mm and with simulated non-calcified stepped stenosis plaques with degrees of 0%, 25%, 50%, and 75% stenosis were scanned with area-detector CT (ADCT) and ultra-high-resolution CT (UHR-CT). Then, ADCT data were reconstructed using all methods, although UHR-CT data were reconstructed with hybrid-type IR, MBIR, and DLR. For the in vivo study, patients who had undergone CCTA at ADCT were retrospectively selected, and each CCTA data set was reconstructed with all methods. To compare the image noise and measurement accuracy at each of the stenosis levels, image noise, and inner diameter were evaluated and statistically compared. To determine the effect of HR-DLR on CAD-RADS evaluation accuracy, the accuracy of CAD-RADS categorization of all CCTAs was compared by using McNemar's test. RESULTS: The image noise of HR-DLR was significantly lower than that of others on ADCT and UHR-CT (p < 0.0001). At a 50% and 75% stenosis level for each phantom, hybrid-type IR showed a significantly larger mean difference on ADCT than did others (p < 0.05). At in vivo study, 31 patients were included. Accuracy on HR-DLR was significantly higher than that on hybrid-type IR, MBIR, or DLR (p < 0.0001). CONCLUSION: HR-DLR is potentially superior for coronary arterial stenosis evaluations to hybrid-type IR, MBIR, or DLR shown on CCTA. KEY POINTS: Question How do coronary arterial stenosis evaluations by hybrid-type IR, MBIR, DLR, and HR-DLR compare to coronary CT angiography? Findings HR-DLR showed significantly lower image noise and more accurate coronary artery disease reporting and data system (CAD-RADS) evaluation than others. Clinical relevance HR-DLR is potentially superior to other reconstruction methods for coronary arterial stenosis evaluations, as demonstrated by coronary CT angiography results on ADCT and as shown in both in vitro and in vivo studies.

Hereby inviting young rising stars in chest radiology in Japan for contributing what they are working currently, we would like to show the potentials and directions of the near future research trends in the research field. I will provide a reflection on my own research topics. At the end, we also would like to discuss on how to choose the themes and topics of research: What to do or not to do? We strongly believe it will stimulate and help investigators in the field.

OBJECTIVE: The purpose of this study was to compare radiation dose reduction capability for accurate liver tumor measurements of a computer-aided volumetry (CADv) software for filtered back projection (FBP), hybrid-type iterative reconstruction (IR), mode-based iterative reconstruction (MBIR), and deep learning reconstruction (DLR) at a phantom study. METHODS: A commercially available anthropomorphic abdominal phantom was scanned five times with a 320-detector row CT at 600 mA, 400 mA, 200 mA, and 100 mA and reconstructed by four methods. Signal-to-noise ratios (SNRs) of all lesions within the arterial and portal-venous phase inserts were calculated, and SNR of the lesion phantom was compared with that of all reconstruction methods by means of Tukey's honestly significant difference (HSD) test. Then, tumor volume (V) of each nodule was automatically measured using commercially available CADv software. To compare dose reduction capability for each reconstruction method at both phases, mean differences between measured V and standard references were compared by Tukey's honestly significant difference test among the four different reconstruction methods on CT obtained at each of the four tube currents. RESULTS: With each of the tube currents, SNRs for MBIR and DLR were significantly higher than those for FBP and hybrid-type IR (p < 0.05). At the arterial phase, the mean difference in V for the CT protocol obtained at 600 or 100 mA and reconstructed with DLR was significantly smaller than that for others (p < 0.05). At the portal-venous phase, the mean differences in V for the CT protocol obtained at 100 mA and reconstructed with hybrid-type IR, MBIR, and DLR were significantly smaller than that for FBP (p < 0.05). CONCLUSIONS: Findings of our phantom study show that reconstruction method had influence on CADv merits for abdominal CT with not only standard but also reduced dose examinations and that DLR can potentially yield better image quality and CADv measurements than FBP, hybrid-type IR, or MBIR in this setting.

PURPOSE: The purpose of this study was to determine the capability of proton density with fat fraction (PD-FFQ) imaging to help assess hematopoietic ability and diagnose aplastic anemia in adults. METHODS: Between January 2021 and March 2023, patients diagnosed with aplastic anemia (AA: n = 14) or myelodysplastic syndrome (MDS: n = 14) were examined by whole-body PD-FFQ imaging, and 14 of 126 age and gender matched patients who had undergone the same PD-FFQ imaging were selected as control group. All proton density fat fraction (PDFF) index evaluations were then performed by using regions of interest (ROIs). Pearson's correlation was used to determine the relationship between blood test results and each quantitative index, and ROC-based positive test and discrimination analyses to compare capability to differentiate the AA from the non-AA group. Finally, sensitivity, specificity and accuracy of all quantitative indexes were compared by means of McNemar's test. RESULTS: Mean PDFF, standard deviation (SD) and percentage of coefficient of variation (%CV) for vertebrae showed significant correlation with blood test results (-0.52 ≤ r ≤ -0.34, p < 0.05). Specificity (SP) and accuracy (AC) of %CV of PDFF in vertebrae were significantly higher than those of mean PDFF in vertebrae and the posterior superior iliac spine (SP: p = 0.0002, AC: p = 0.0001) and SD of PDFF in vertebrae (SP: p = 0.008, AC: p = 0.008). Moreover, AC of SD of PDFF in vertebrae was significantly higher than that of mean PDFF in vertebrae and the posterior superior iliac spine (p = 0.03). CONCLUSION: Whole-body PD-FFQ imaging is useful for hematopoietic ability assessment and diagnosis of aplastic anemia in adults.

BACKGROUND: We aimed to determine the capabilities of compressed sensing (CS) and deep learning reconstruction (DLR) with those of conventional parallel imaging (PI) for improving image quality while reducing examination time on female pelvic 1.5-T magnetic resonance imaging (MRI). METHODS: Fifty-two consecutive female patients with various pelvic diseases underwent MRI with T1- and T2-weighted sequences using CS and PI. All CS data was reconstructed with and without DLR. Signal-to-noise ratio (SNR) of muscle and contrast-to-noise ratio (CNR) between fat tissue and iliac muscle on T1-weighted images (T1WI) and between myometrium and straight muscle on T2-weighted images (T2WI) were determined through region-of-interest measurements. Overall image quality (OIQ) and diagnostic confidence level (DCL) were evaluated on 5-point scales. SNRs and CNRs were compared using Tukey's test, and qualitative indexes using the Wilcoxon signed-rank test. RESULTS: SNRs of T1WI and T2WI obtained using CS with DLR were higher than those using CS without DLR or conventional PI (p < 0.010). CNRs of T1WI and T2WI obtained using CS with DLR were higher than those using CS without DLR or conventional PI (p < 0.003). OIQ of T1WI and T2WI obtained using CS with DLR were higher than that using CS without DLR or conventional PI (p < 0.001). DCL of T2WI obtained using CS with DLR was higher than that using conventional PI or CS without DLR (p < 0.001). CONCLUSION: CS with DLR provided better image quality and shorter examination time than those obtainable with PI for female pelvic 1.5-T MRI. RELEVANCE STATEMENT: CS with DLR can be considered effective for attaining better image quality and shorter examination time for female pelvic MRI at 1.5 T compared with those obtainable with PI. KEY POINTS: Patients underwent MRI with T1- and T2-weighted sequences using CS and PI. All CS data was reconstructed with and without DLR. CS with DLR allowed for examination times significantly shorter than those of PI and provided significantly higher signal- and CNRs, as well as OIQ.

The high frequency of productive cough in idiopathic pulmonary fibrosis (IPF) impacts quality of life. Reduced normal lung volume is linked to cough severity, predicting poorer outcomes. Insights could enhance IPF management and patient wellbeing. https://bit.ly/4bPOCzC.

BACKGROUND: Patients with idiopathic pulmonary fibrosis (IPF) often experience sarcopenia and malnutrition. However, this has not been fully examined through longitudinal surveys. This study investigated whether sarcopenia and malnutrition were associated with 1-year outcomes in IPF. METHODS: We evaluated sarcopenia and nutritional status in 64 outpatients with IPF. We assessed the time-to-event for respiratory-related hospitalizations or deaths 12 months after enrollment. Sarcopenia was diagnosed by the criteria of the Asian Working Group for Sarcopenia, 2019. Nutritional status was assessed by serum transthyretin and the Geriatric Nutritional Risk Index (GNRI). RESULTS: The average age was 73.6 ± 7.9 years, and the percent predicted forced vital capacity (FVC) was 81.9 ± 15.7%. Of the 64 patients, 24 (37.5%) had sarcopenia. The median serum transthyretin level and mean GNRI were 23.8 mg/dL and 102, respectively. Eleven patients (17.2%) experienced respiratory-related hospitalization or death within the first year. Cox regression analysis showed that the % predicted diffusion capacity for carbon monoxide, lowest oxygen saturation in the 6-min walk test, serum transthyretin level, and GNRI were significant predictors of 1-year outcomes. The Kaplan-Meier method, which divided the patients into two groups based on a transthyretin level of 22.6 mg/dL, showed a significant difference (P < 0.001, log-rank test). Sarcopenia and the percent predicted FVC did not predict the 1-year outcomes. CONCLUSIONS: This pilot study represents the first longitudinal survey assessing patients with IPF for sarcopenia and malnutrition. Serum transthyretin levels may predict respiratory-related hospitalization or death within 1 year in patients with IPF.

BACKGROUND: Dupilumab exerts clinical effects, including improved sinus opacification, olfactory function, and quality of life, in patients with severe chronic rhinosinusitis with nasal polyps (CRSwNP). Meanwhile, only a few studies have reported its effects on nasal airway resistance and olfactory function, particularly in the Japanese population. Predictors of response remain unclear. OBJECTIVE: In this prospective, observational study, we assessed the comprehensive efficacy and therapeutic response to dupilumab in severe CRSwNP patients with comorbid asthma. METHODS: In 16 adult severe CRSwNP patients with comorbid asthma, the efficacy of 48-week dupilumab treatment, including olfactory function measured by a T&T olfactometer, nasal airway resistance measured by rhinomanometry, nasal polyp score, Lund-Mackay computed tomography score (LMS), and 22-item Sinonasal Outcome Test (SNOT-22), was assessed. Regarding asthma, the annualized rate of exacerbations, 7-item Asthma Control Questionnaire (ACQ-7), and spirometry were assessed. Treatment responsiveness was analyzed. RESULTS: With 48-week dupilumab treatment, olfactory function, nasal airway resistance, nasal polyp score, LMS, and SNOT-22 scores improved significantly. Regarding comorbid asthma, the rate of exacerbations decreased, and ACQ-7 scores and lung function improved significantly. According to the European Position Paper on Rhinosinusitis and Nasal Polyps 2022/European Forum for Research and Education in Allergy and Airway Diseases criteria, 15 patients (94%) were moderate-to-excellent responders at 48 weeks of treatment. Patients with higher SNOT-22 scores, ACQ-7 scores, rates of asthma exacerbation in the previous year, and blood eosinophil counts benefited more from treatment. CONCLUSION: Dupilumab improved upper and lower airway outcomes especially in severe CRSwNP patients with comorbid, poorly controlled asthma.

BACKGROUND: Diffusion-weighted images (DWI) obtained by echo-planar imaging (EPI) are frequently degraded by susceptibility artifacts. It has been suggested that DWI obtained by fast advanced spin-echo (FASE) or reconstructed with deep learning reconstruction (DLR) could be useful for image quality improvements. The purpose of this investigation using in vitro and in vivo studies was to determine the influence of sequence difference and of DLR for DWI on image quality, apparent diffusion coefficient (ADC) evaluation, and differentiation of malignant from benign head and neck tumors. METHODS: For the in vitro study, a DWI phantom was scanned by FASE and EPI sequences and reconstructed with and without DLR. Each ADC within the phantom for each DWI was then assessed and correlated for each measured ADC and standard value by Spearman's rank correlation analysis. For the in vivo study, DWIs obtained by EPI and FASE sequences were also obtained for head and neck tumor patients. Signal-to-noise ratio (SNR) and ADC were then determined based on ROI measurements, while SNR of tumors and ADC were compared between all DWI data sets by means of Tukey's Honest Significant Difference test. RESULTS: For the in vitro study, all correlations between measured ADC and standard reference were significant and excellent (0.92 ≤ ρ ≤ 0.99, p < 0.0001). For the in vivo study, the SNR of FASE with DLR was significantly higher than that of FASE without DLR (p = 0.02), while ADC values for benign and malignant tumors showed significant differences between each sequence with and without DLR (p < 0.05). CONCLUSION: In comparison with EPI sequence, FASE sequence and DLR can improve image quality and distortion of DWIs without significantly influencing ADC measurements or differentiation capability of malignant from benign head and neck tumors.

BACKGROUND: Dupilumab has clinical effects in patients with moderate-to-severe asthma. When considering interleukin (IL)-4 and IL-13 signaling, effects of dupilumab on airway mucus hypersecretion and airway remodeling are expected, but they have been reported in only a few short-term studies. Its efficacy for airway hyperresponsiveness (AHR) remains unknown. We comprehensively assessed the efficacy of dupilumab, especially for subjective and objective measures of airway mucus hypersecretion and airway dimensions in moderate-to-severe asthmatic patients. METHODS: In 28 adult patients with moderate-to-severe uncontrolled asthma, the comprehensive efficacy of 48-week dupilumab treatment, including the Cough and Sputum Assessment Questionnaire (CASA-Q), radiological mucus scores and airway dimensions on computed tomography (CT), was assessed prospectively. Treatment responsiveness to dupilumab was analyzed. RESULTS: With 48-week dupilumab treatment, all four cough and sputum domain scores of CASA-Q improved significantly. Radiological mucus scores and airway wall thickening on CT were significantly decreased. The decreases in mucus scores were significantly associated with improvements in Asthma Control Questionnaire scores, Asthma Quality of Life Questionnaire (AQLQ) overall scores, airway obstruction, and airway type 2 inflammation. When defined by > 0.5 improvement in AQLQ overall scores, 18 patients (64%) were identified as responders. CONCLUSIONS: Dupilumab reversed subjective and objective measures of airway mucus hypersecretion and some aspects of airway remodeling in patients with moderate-to-severe uncontrolled asthma.

PURPOSE: The purpose of this study was to determine the utility of compressed sensing (CS) with deep learning reconstruction (DLR) for improving spatial resolution, image quality and focal liver lesion detection on high-resolution contrast-enhanced T1-weighted imaging (HR-CE-T1WI) obtained by CS with DLR as compared with conventional CE-T1WI with parallel imaging (PI). METHODS: Seventy-seven participants with focal liver lesions underwent conventional CE-T1WI with PI and HR-CE-T1WI, surgical resection, transarterial chemoembolization, and radiofrequency ablation, followed by histopathological or >2-year follow-up examinations in our hospital. Signal-to-noise ratios (SNRs) of liver, spleen and kidney were calculated for each patient, after which each SNR was compared by means of paired t-test. To compare focal lesion detection capabilities of the two methods, a 5-point visual scoring system was adopted for a per lesion basis analysis. Jackknife free-response receiver operating characteristic (JAFROC) analysis was then performed, while sensitivity and false positive rates (/data set) for consensus assessment of the two methods were also compared by using McNemar's test or the signed rank test. RESULTS: Each SNR of HR-CE-T1WI was significantly higher than that of conventional CE-T1WI with PI (p < 0.05). Sensitivities for consensus assessment showed that HR-CE-MRI had significantly higher sensitivity than conventional CE-T1WI with PI (p = 0.004). Moreover, there were significantly fewer FP/cases for HR-CE-T1WI than for conventional CE-T1WI with PI (p = 0.04). CONCLUSION: CS with DLR are useful for improving spatial resolution, image quality and focal liver lesion detection capability of Gd-EOB-DTPA enhanced 3D T1WI without any need for longer breath-holding time.

PURPOSE: The purpose of this in vivo study was to determine the effect of reverse encoding direction (RDC) on apparent diffusion coefficient (ADC) measurements and its efficacy for improving image quality and diagnostic performance for differentiating malignant from benign tumors on head and neck diffusion-weighted imaging (DWI). METHODS: Forty-eight patients with head and neck tumors underwent DWI with and without RDC and pathological examinations. Their tumors were then divided into two groups: malignant (n = 21) and benign (n = 27). To determine the utility of RDC for DWI, the difference in the deformation ratio (DR) between DWI and T2-weighted images of each tumor was determined for each tumor area. To compare ADC measurement accuracy of DWIs with and without RDC for each patient, ADC values for tumors and spinal cord were determined by using ROI measurements. To compare DR and ADC between two methods, Student's t-tests were performed. Then, ADC values were compared between malignant and benign tumors by Student's t-test on each DWI. Finally, sensitivity, specificity and accuracy were compared by means of McNemar's test. RESULTS: DR of DWI with RDC was significantly smaller than that without RDC (p < 0.0001). There were significant differences in ADC between malignant and benign lesions on each DWI (p < 0.05). However, there were no significant difference of diagnostic accuracy between the two DWIs (p > 0.05). CONCLUSION: RDC can improve image quality and distortion of DWI and may have potential for more accurate ADC evaluation and differentiation of malignant from benign head and neck tumors.

Lesions in the middle and posterior mediastinum are relatively rare, but there are some useful radiological clues that can be used to diagnose them precisely. It is useful to determine the affected mediastinal compartment and the locations of the main thoracic nerves on medical images for diagnosing such mediastinal lesions. Neurogenic tumors can occur in the middle mediastinum, although they generally arise as posterior mediastinal tumors. Based on the above considerations, we review various characteristic imaging findings of middle and posterior mediastinal lesions, and their differential diagnoses.

Background: It is difficult to detect a common trunk of the left pulmonary vein (PV) preoperatively, which may cause intraoperative accidental complications. The purpose of this study is to establish a simple and reliable method of detecting a common trunk in preoperative computed tomography (CT) images. Methods: A total of 428 patients who underwent thin-section CT preoperatively for left lung cancer at 4 institutions were reviewed. The characteristic findings of a common trunk in the axial view were considered by confirming the preoperative CT findings of cases that had been verified to have a common trunk based on intraoperative findings. The CT images were reviewed independently by two evaluators. Results: We found that the distance between the mediastinal side of the left lower bronchus and the junction of two left PVs was extremely short in the cases with a common trunk in the axial view. In a typical case, the axial section of the bronchus is close to the junction. Of the 416 patients that were evaluable among the 428 total patients, 26 (6.3%) were diagnosed as having a common trunk by both evaluators, and the diagnosis was coincident in 413 patients (99.2%). We were able to evaluate the surgical videos of 16 of the 26 patients, and a common trunk was confirmed in 15 patients (94%). Conclusions: We established a simple and reliable method of detecting a common trunk of the left PV in the axial view on chest CT that was routinely performed prior to lung cancer surgery.

<sec><title>Background</title> In adrenal vein sampling, selecting the right adrenal vein is technically difficult and it is important to evaluate the right adrenal vein anatomy before adrenal vein sampling. The advanced monoenergetic reconstruction technique has recently become available and we hypothesized that this technique may be useful. </sec><sec><title>Purpose</title> To evaluate the usefulness of the advanced monoenergetic reconstruction technique in dual-energy computed tomography (CT; advanced monoenergetic images) for evaluation of vascular anatomy before adrenal vein sampling. </sec><sec><title>Material and Methods</title> Twenty-one patients underwent three-phase (20, 30, and 70 s) contrast-enhanced CT before adrenal vein sampling. Advanced monoenergetic images were reconstructed at 40 keV and analyzed objectively and subjectively in comparison with the standard 120-kVp images. As objective evaluation, the signal-to-noise ratio and contrast-to-noise ratio of the right adrenal vein were assessed. As subjective evaluation, two radiologists assessed the delineation of the right adrenal vein using a 5-point Likert scale (1 = poor, 5 = excellent). Furthermore, the technical success rate of adrenal vein sampling and procedure time were also evaluated. </sec><sec><title>Results</title> There was no difference in the signal-to-noise ratio between the two groups. The contrast-to-noise ratios of the right adrenal vein of advanced monoenergetic images were higher than those of the standard images ( P &lt; 0.05). The Likert scores of advanced monoenergetic images were higher than those of the standard images ( P &lt; 0.05). The technical success rate of adrenal vein sampling was 95% (20/21) and the median of procedure time was 103 min (range = 59–197 min). </sec><sec><title>Conclusion</title> Advanced monoenergetic imaging appears to be useful in the delineation of the right adrenal vein before adrenal vein sampling. </sec>

BACKGROUND: Eosinophilic nasal polyps (NPs) are associated with the presence of asthma in chronic rhinosinusitis (CRS) patients. Serum periostin has been considered a relevant biomarker for unified airway diseases. OBJECTIVE: To determine the utility of biomarkers including serum periostin that reflects reduction of exacerbations of comorbid asthma in CRS patients. METHODS: We prospectively recruited 56 CRS patients who were subjected to undergo endoscopic sinus surgery (ESS) (20 with asthma) between October 2015 and December 2017 and followed them for 1 year after ESS. Blood eosinophil count, serum periostin, and fractional nitric oxide (FeNO) were measured at enrollment. How these type 2-driven biomarkers reflect comorbid asthma was determined using receiver operating characteristic (ROC) analysis. The frequency of asthma exacerbations during 1 year was counted both before and after ESS. Associations between preoperative biomarkers including eosinophils in NPs and asthma exacerbations were evaluated. RESULTS: Blood eosinophil count, FeNO, and serum periostin levels were significantly higher in CRS patients with asthma than in those without (p < 0.01 for all) and discriminated comorbid asthma among CRS patients (p < 0.05; AUC > 0.80 for all). The increased preoperative serum periostin correlated with lower absolute number of postoperative exacerbations (ρ = -0.49, p = 0.03) and its relative reduction after ESS (ρ = 0.53, p = 0.03) in asthmatic patients. Increased eosinophils in NPs were also associated with reduced asthma exacerbations. CONCLUSION: Preoperative increased serum periostin and eosinophils in NPs are associated with the preventive effect of ESS for asthma exacerbations in CRS patients comorbid with asthma.

A 6-year-old girl was admitted to our hospital due to discharging the strobila of a tapeworm (Diphyllobothrium nihonkaiense) from her anus. Before excreting the tapeworm completely with anthelmintics, ultrasonography was performed. The tapeworm was shown as a slightly high echoic strand-like lesion on ultrasonography in the terminal ileum. In this strand-like lesion, some high echoic spots were detected. This finding was considered as a characteristic of Diphylloborthriasis.

70歳男性。舌背部の結節と咳を主訴とした。胸膜炎の既往があり、喫煙を48年間(20本/日)継続していた。CTで多発肺腫瘍、縦隔・肺門部、左腋窩・左鎖骨上窩リンパ節の腫大を認めた。舌病変の生検、肺野病変の気管支鏡下生検で左上葉原発性肺腺癌(EGFR遺伝子変異が陽性)と舌転移の診断を得た。FDG-PET/CTによる全身検索で左内深頸リンパ節、右顎下リンパ節、L3椎体に集積を認めた。また、左上葉S3に25×20×28mmを最大とし、両肺に多発する結節を認め、集積亢進を伴っていた。造影MRIによる全身検索では舌背部、両側大脳、小脳に結節を認めた。以上より、左上葉原発性肺腺癌cT1N3M1c、Stage IVと診断した。分子標的薬EGFR-TKI(エルロチニブ150mg/日)の投与を開始し、15日後に舌腫瘍、肺腫瘍および脳転移巣が縮小した。

© 2018, Iranian Journal of Radiology. Background: CT angiography (CTA) was routinely performed for carotid artery disease, but the plaque characterization based on measurement of density may be inaccurate, influenced by adjacent calcification and contrast agent. Remodeling ratio was one of the additional new objective indexes for plaque characterization. On coronary CTA, the utility of histogram analysis was reported in a few studies. Objectives: The purpose of this study was to evaluate the diagnostic value of histogram analysis of carotid artery plaque density and positive remodeling on CTA for the diagnosis of pathologically proven complicated carotid artery plaques. Patients and Methods: We retrospectively evaluated 29 patients with atherosclerotic carotid artery stenosis treated by carotid endarterectomy. On CTA, the boundaries of non-calcified plaques were manually traced at the site of the greatest stenosis. In addition to the mean plaque density, the percentage of pixels (PP) with a density of less than 30 Hounsfield units (HU) (PP < 30) was calculated using the histogram analysis. We calculated the remodeling ratio by dividing the cross-sectional artery area at the greatest stenosis by normal reference-segment artery area. These results of CTA analysis were compared with the results of histological analysis based on the American heart association criteria. Results: Histologically, 13 of the 29 patients had complicated plaques. PP < 30 and the remodeling ratio were higher in patients with complicated plaques than in those with uncomplicated plaques (P = 0.023 and 0.002, respectively). Whereas, the mean plaque density did not differ between the two groups (P = 0.062). Correlation between PP < 30 and the remodeling ratio was stronger than the correlation between PP < 30 and the mean density (Spearman’s rs = 0.76 vs. 0.65, respectively). Conclusion: Histogram analysis of the carotid artery plaque density may be more useful for the evaluation of atherosclerosis on CTA compared with the conventional analysis of plaque densities, and the combined analysis of histogram analysis and the remodeling ratio may help to predict future stroke events.

PURPOSE: To evaluate the efficacy and safety of transcatheter arterial embolization (TAE) for renal angiomyolipoma (AML) using a micro-balloon catheter and a mixture of ethanol and lipiodol. MATERIALS AND METHODS: Twelve consecutive patients with 15 AMLs, 9 females and 3 males, with a median age of 44 years (range, 11-81), underwent this procedure between 2011 and 2016. In all procedures, a micro-balloon catheter was advanced to the feeding artery of the AML and TAE was performed with a mixture of ethanol and lipiodol under balloon inflation. We reviewed medical records and images, and evaluated the technical success rate, clinical success rate, and complications. Technical success was defined as completion of TAE using the micro-balloon catheter and the mixture of ethanol and lipiodol. Clinical success was defined as reduction of tumor size on CT, which was performed before and after TAE. RESULTS: In 14 of 15 AMLs, the micro-balloon catheter could be advanced to the feeding artery, and TAE was performed successfully. Thus, the technical success rate was 93%. Among these 14 AMLs of 11 patients, 13 AMLs of 10 patients could be followed and tumor shrinkage was confirmed in all. Thus, the clinical success rate was 100%. Four patients had mild symptoms after TAE; the minor complication rate was 33% (4/12), and the major complication rate was 0%. CONCLUSION: TAE for renal AML using the micro-balloon catheter and mixture of ethanol and lipiodol appears to be effective and safe.

Purpose Recently, it has been recognized that pathologically proven progressive supranuclear palsy (PSP) cases are classified into various clinical subtypes with non-uniform symptoms and imaging findings. This article reviews essential imaging findings, general information, and advanced magnetic resonance imaging (MRI) techniques for PSP and presents these MRI findings of pathologically proven typical and atypical PSP cases for educational purposes. Methods With the review of literatures, notably including atypical pathologically proven PSP cases, MRI and clinical information of 15 pathologically proven typical and atypical PSP cases were retrospectively evaluated. Results In addition to typical symptoms, PSP patients can exhibit atypical symptoms including levodopa-responsive parkinsonism, pure akinesia, non-fluent aphasia, corticobasal syndrome, and predominant cerebellar ataxia. As well as clinical symptoms, the degree of midbrain atrophy, a well-known imaging hallmark, is not consistent in atypical PSP cases. This fact has important implications for the limitation of midbrain atrophy as a diagnostic imaging biomarker of PSP pathology. Additional evaluation of other imaging findings including various regional atrophies of the globus pallidus, frontal lobe, cerebral peduncle, and superior cerebellar peduncle is essential for the diagnosis of atypical PSP cases. Conculsion It is necessary for radiologists to recognize the wide clinical and radiological spectra of typical and atypical PSP cases.

Background: Preoperative evaluation of invasion to the adjacent organs is important for the thymic epithelial tumors on CT. The purpose of our study was to evaluate the utility of electrocardiography (ECG)-gated CT for assessing thymic epithelial tumors with regard to the motion artifacts produced and the preoperative diagnostic accuracy of the technique. Material/Methods: Forty thymic epithelial tumors (36 thymomas and 4 thymic carcinomas) were examined with ECGgated contrast-enhanced CT using a dual source scanner. The scan delay after the contrast media injection was 30 s for the non-ECG-gated CT and 100 s for the ECG-gated CT. Two radiologists blindly evaluated both the non-ECG-gated and ECG-gated CT images for motion artifacts and determined whether the tumors had invaded adjacent structures (mediastinal fat, superior vena cava, brachiocephalic veins, aorta, pulmonary artery, pericardium, or lungs) on each image. Motion artifacts were evaluated using a 3-grade scale. Surgical and pathological findings were used as a reference standard for tumor invasion. Results: Motion artifacts were significantly reduced for all structures by ECG gating (p=0.0089 for the lungs and p&lt 0.0001 for the other structures). Non-ECG-gated CT and ECG-gated CT demonstrated 79% and 95% accuracy, respectively, during assessments of pericardial invasion (p=0.03). Conclusions: ECG-gated CT reduced the severity of motion artifacts and might be useful for preoperative assessment whether thymic epithelial tumors have invaded adjacent structures.

PURPOSE: We evaluated the ability of dual source CT (DSCT) with ECG-triggered high-pitch spiral acquisition (Flash Spiral Cardio mode) to depict the morphological features of ventricles in pediatric patients with congenital heart defects (CHD). MATERIALS AND METHODS: Between July 2013 and April 2015, 78 pediatric patients with CHD (median age 4 months) were examined using DSCT with the Flash Spiral Cardio mode. The types of ventricular abnormalities were ventricular septal defect (VSD) in 42 (the malaligned type in 11, perimembranous type in 23, supracristal type in 2, atrioventricular type in 2, and muscular type in 4), single ventricle (SV) in 11, and congenital corrected transposition of the great arteries (ccTGA) in 4. We evaluated the accuracy of the diagnosis of the VSD type. In cases of SV and ccTGA, we assessed the detectability of the anatomical features of both ventricles for a diagnosis of ventricular situs. RESULTS: DSCT confirmed the diagnoses for all VSDs. The type of defect was precisely diagnosed for all patients. The anatomical features of both ventricles were also depicted and ventricular situs of SV and ccTGA was correctly diagnosed. CONCLUSION: The results suggest that DSCT has the ability to clearly depict the configuration of ventricles.

Background: Preoperative transcatheter arterial embolization for hypervascular bone and soft tissue tumors plays an important role in reducing intraoperative blood loss (IBL). Purpose: To evaluate the use of a gelatin sponge in preoperative transcatheter arterial embolization for hypervascular bone and soft tissue tumors in the pelvis or extremities. Material and Methods: Thirty-seven patients (21 men, 16 women median age, 61 years age range, 23-79 years) underwent preoperative transcatheter arterial embolization between April 2004 and January 2015. Medical records and images were reviewed, and the technical success rate, clinical success rate, and complications were evaluated. Technical success was defined as a devascularization rate of 75% or higher, and clinical success was defined as intraoperative blood loss (IBL) &lt 1500 mL in cases undergoing surgery within 3 days of transarterial embolization and &lt 3000 mL in cases operated 4 or more days later. Results: Tumor sizes were in the range of 2.0-13.0 cm (median, 5.0 cm). The devascularization rate was decreased by &gt 75% at follow-up angiography in all cases, and the technical success rate was 100 % (37/37). The median IBL was 491 mL (range, 30-3800 mL), and the clinical success rate was 89% (33/37). The minor complication of local pain was observed in 13 out of 37 cases (35%) during or after embolization, but was controllable by an analgesic. Conclusion: Preoperative transarterial embolization using a gelatin sponge appears to be feasible and safe, and may contribute to decreasing IBL.

Objective: Laparoscopic transverse colectomy is challenging owing to technical difficulties in identifying an adequate dissection plane, ligating and dissecting lymph nodes around the middle colic vessels. One of the reasons for the technical difficulties is the complex relationship between the middle colic vein (MCV) and its tributary. So, defining the venous anatomy around the MCV before laparoscopic surgery seems important to avoid massive bleeding. The purpose of this study was to evaluate the depiction rate and variation of the MCV and its tributaries on three-dimensional CT angiography (3DCTA). Methods: This study included 331 patients (203 males and 128 females) scheduled for laparoscopic surgery between June 2010 and April 2012. Most of the patients had gastric or colorectal cancer. Patients who needed emergency surgeries for obstruction or perforation were excluded. 3DCTA with an i.v. contrast medium was performed immediately following the administration of effervescent granules or room air insufflation. We assessed variations of the MCV tributaries using transaxial, multiplanar reconstructed images and volume-rendering images. Results: The MCV could be identified in all patients. The MCVs drained into the superior mesenteric vein in 62.5% of patients, gastrocolic trunk of Henle in 29.3% of patients, inferior mesenteric vein in 4.8% of patients, splenic vein in 2.7% of patients and jejunal vein in 0.6% of patients. Conclusion: 3DCTA is useful in evaluating the anatomic variants of the MCV in pre-operative planning for laparoscopic surgery. Advances in knowledge: Use of 3DCTA for the recognition of the anatomic complexity around the MCV and its tributary plays an important role in pre-operative planning for optimal patient outcome.

PURPOSE: We examined whether the shortened breath-hold 3-dimensional volumetric interpolated breath-hold examination (3D-VIBE) sequence for high acceleration factor (AF) using the controlled aliasing in parallel imaging results in higher acceleration (CAIPIRINHA) could substitute for the conventional sequence using generalized autocalibrating partially parallel acquisition (GRAPPA) in patients undergoing routine gadoxetic acid-enhanced liver MRI. MATERIALS AND METHODS: Thirty patients with clinically suspected focal liver lesions were scanned using 3D-VIBE sequences with GRAPPA with AF = 2 and AF = 4 and CAIPIRINHA with AF = 4 (acquisition times: 21, 14, and 12 s, respectively) during the hepatobiliary phase. Visual evaluations using a 3- or 5-point scale and signal-to-noise ratio (SNR) analysis were performed for the 3 sequences. RESULTS: For CAIPIRINHA with AF = 4, there was significantly less image noise in both visual evaluation and SNR analysis and fewer parallel imaging artifacts than for GRAPPA with AF = 4 (P < 0.0005); it was equal to GRAPPA with AF = 2 and had fewer motion artifacts than GRAPPA with AF = 2 and 4 (P < 0.0012). The liver edge sharpness and hepatic vessel clarity, lesion conspicuity, and overall image quality were rated significantly higher with CAIPIRINHA with AF = 4 than GRAPPA with AF = 2 and AF = 4 (P < 0.009). For GRAPPA with AF = 4, lesion conspicuity and overall image quality were rated significantly lower than for GRAPPA with AF = 2 (P < 0.012). CONCLUSION: The shortened breath-hold 3D-VIBE sequence using the new CAIPIRINHA technique with a high AF of 4 was superior to the conventional GRAPPA sequence. The shortened breath-hold sequence using GRAPPA with a high AF of 4 worsened the image quality and lesion conspicuity.

Background: Lower tube voltage has advantages for CT angiography, such as improved contrast Objective: To evaluate the image quality of low-voltage (70 kV) CT for congenital heart disease and the ability of sinogram-affirmed iterative reconstruction to improve image quality. Materials and methods: Forty-six children with congenital heart disease (median age: 109 days) were examined using dual-source CT. Scans were performed at 80 kV and 70 kV in 21 and 25 children, respectively. A nonionic iodinated contrast medium (300 mg I/ml) was used for the 80-kV protocol. The contrast medium was diluted to 75% (225 mgI/mL) with saline for the 70-kV protocol. Image noise was measured in the two protocols for each group by extracting the standard deviations of a region of interest placed on the descending aorta. We then determined whether sinogram-affirmed iterative reconstruction reduced the image noise at 70 kV. Results: There was more noise at 70 kV than at 80 kV (29 ± 12 vs 20 ± 4.8 P &lt 0.01). Sinogram-affirmed iterative reconstruction with grade 4 strength settings improved the noise (20 ± 5.9 P &lt 0.01) for the 70-kV group. Conclusion: Sinogram-affirmed iterative reconstruction improved the image quality of CT in congenital heart disease.

OBJECTIVE: Although a correct diagnosis is important for appropriate management, accurately differentiating between multiple system atrophy with predominant parkinsonism (MSA-P) and Parkinson's disease (PD) is often difficult because of similarities in the early-stage symptoms. The aim of this study was to evaluate the diagnostic value of cerebral perfusion single photon emission computed tomography (SPECT) and voxel-based analysis for diagnosing MSA-P patients. METHODS: Thirty-eight subjects (9 with early-stage MSA-P, 11 with PD, and 18 controls) were included in this study. Z-scores suggestive of hypoperfusion were calculated between patients and controls using statistical parametric mapping (SPM) 8 and easy Z-score imaging system (eZIS) programs. A voxel-based stereotactic extraction estimation (vbSEE) program was performed to determine the target volumes of interest (VOIs) in the putamen, pons, and cerebellum, and quantify Z-scores as "extent" (the rate of voxels with a Z-score >2.0 in these VOIs) and "severity" (average Z-scores in these VOIs). These parameters were used as the determinant in receiver operating characteristic (ROC) analyses. RESULTS: The extent and severity of the cerebellar VOIs were higher in MSA-P patients than in PD patients. In ROC analyses, the extent and severity of the cerebellar VOI exhibited the highest areas under the curves of 0.86 and 0.84, and accuracies of 90 and 90 %, respectively. CONCLUSIONS: The diagnostic value of significant cerebellar hypoperfusion was the highest for differentiating MSA-P from PD. This voxel-based analysis of cerebral perfusion SPECT using the SPM8, eZIS, and vbSEE programs is useful for clinically diagnosing MSA-P.

Objective: The application of bronchial artery embolization (BAE) using N-butyl-2-cyanoacrylate (NBCA) for haemoptysis was recently reported to be useful. A triple co-axial (triaxial) system consisting of a 4-Fr catheter, 2.7-Fr microcatheter and 1.9-Fr no-taper microcatheter has been developed. The aim of the present study was to evaluate the usefulness of the triaxial system in BAE using NBCA. Methods: 12 patients with haemoptysis, 8 males and 4 femaleswith amedian age of 64 years (range, 49-88 years), underwent BAE between August 2012 and October 2014. Medical records and images were reviewed, and the technical success rate, clinical success rate, haemoptysisfree rate and complications were evaluated. Technical success was defined as the complete cessation of the target artery as confirmed by digital subtraction angiography, whereas clinical success was defined as the cessation of haemoptysis within 24 h of BAE. Recurrent haemoptysis was defined as a total of &gt 30 ml of bleeding per day. Results: The target artery was embolized successfully in all patients, and the technical success rate was 100% (12/12). The cessation of haemoptysis was achieved in 11 out of 12 patients within 24h, and thus, the clinical success rate was 92% (11/12). The 6-, 12- and 24-month haemoptysis-free rates were 89%, 89% and 76%, respectively. No patients exhibited any signs of complications such as spinal ischaemia. Conclusion: BAE using the triaxial system and NBCA appears to be a useful and safe procedure for haemoptysis. Advances in knowledge: The triaxial system contributes to safe and effective BAE using NBCA.

Materials and Methods This procedure was performed on 161 lesions in 154 patients (75 men and 79 women median age, 62 years age range 23-89 years). Medical records and images were reviewed, and the technical success rate, surgical success rate and complications were evaluated. Technical success was defined as successful hookwire marking at the target site without marker dropping before VATS. Surgical success was defined as negative surgical margins on pathological examination after VATS. Purpose The aim of this study was to evaluate the technical and clinical efficacy and safety of CT-guided hookwire marking before video-assisted thoracoscopic surgery (VATS) for small pulmonary lesions. Results There were 97 nodules and 64 ground-glass opacities, and their mean size was 9.8 mm (range 2-34). The technical success rate was 97.5% (157/161). In three of the four failed cases, another hookwire marker was placed, and in the remaining case, VATS was performed without a marker. The surgical success rate was 98.1% (158/161). In the three failed cases, the margin was positive, so lung lobectomy was performed in one case, and the other two cases were observed carefully. Complication rates were as follows: pneumothorax, 37.9% (61/161) focal intrapulmonary haemorrhage, 34.8% (58/139) haemoptysis, 0.6% (1/161) haemothorax, 0% (0/161) air embolism, 0.6% (1/161) dissemination, 0% (0/161) and death, 0% (0/161). Conclusion CT-guided hookwire marking appears to be useful for VATS, but the procedure may, although rarely, cause severe complications such as air embolism.