High-risk imaging characteristics in left ventricular apex for the life-threatening arrhythmic events in Japanese hypertrophic cardiomyopathy patients.

Left ventricular (LV) apical aneurysm is known to be associated with the life-threatening arrhythmic events in hypertrophic cardiomyopathy (HCM). However, the current 2014 ESC guideline has not included apical aneurysm as a major risk factor for sudden cardiac death and 2018 JCS guideline includes it only as a modulator, while it has been included as a new major risk marker in 2020 AHA/ACC guideline. Therefore, we sought to identify high-risk imaging characteristics in LV apex which is associated with a higher occurrence of ventricular tachycardia/fibrillation (VT/VF). In 99 consecutive Japanese HCM patients (median age, 65 years; 59 males) undergoing implantable cardioverter-defibrillator (ICD) implantation for primary prevention following cardiac magnetic resonance including late gadolinium enhancement (LGE), the occurrence of appropriate ICD interventions for VT/VF was evaluated for 6.2 (median) years after ICD implantation. Overall, appropriate ICD interventions occurred in 43% with annual rates of 7.0% for appropriate interventions. Kaplan-Meier analysis demonstrated that the presence of LV apical aneurysm was significantly associated with a higher occurrence of appropriate interventions (annual rates 18.9% vs. 6.4%, P = 0.013). Similarly, patients with high LV mid-to-apex pressure gradient (annual rates 14.9% vs. 6.2%, P = 0.022) and presence of apical LGE (annual rates 10.9% vs. 4.0%, P = 0.001) experienced appropriate interventions more frequently. An aneurysm, high-pressure gradient, and LGE in an apex are associated with VT/VF. These characteristics in apex should be kept in mind when implanting ICD in Japanese HCM patients as a primary prevention.

Clinical validity of non-contrast-enhanced VI-RADS: prospective study using 3-T MRI with high-gradient magnetic field.

OBJECTIVES: To develop a modified Vesical Imaging Reporting and Data System (VI-RADS) without dynamic contrast-enhanced imaging (DCEI), termed "non-contrast-enhanced VI-RADS (NCE-VI-RADS)", and to assess the additive impact of denoising deep learning reconstruction (dDLR) on NCE-VI-RADS. METHODS: From January 2019 through December 2020, 163 participants who underwent high-gradient 3-T MRI of the bladder were prospectively enrolled. In total, 108 participants with pathologically confirmed bladder cancer by transurethral resection were analyzed. Tumors were evaluated based on VI-RADS (scores 1-5) by two readers independently: an experienced radiologist (reader 1) and a senior radiology resident (reader 2). Conventional VI-RADS assessment included all three imaging types (T2-weighted imaging [T2WI], diffusion-weighted imaging [DWI], and dynamic contrast-enhanced imaging [DCEI]). Also evaluated were NCE-VI-RADS comprising only non-contrast-enhanced imaging types (T2WI and DWI), and "NCE-VI-RADS with dDLR" comprising T2WI processed with dDLR and DWI. All systems were assessed using receiver-operating characteristic curve analysis and simple and/or weighted κ statistics. RESULTS: Muscle invasion was identified in 23/108 participants (21%). Area under the curve (AUC) values for diagnosing muscle invasion were as follows: conventional VI-RADS, 0.94 and 0.91; NCE-VI-RADS, 0.93 and 0.91; and "NCE-VI-RADS with dDLR", 0.96 and 0.93, for readers 1 and 2, respectively. Simple κ statistics indicated substantial agreement for NCE-VI-RADS and almost perfect agreement for conventional VI-RADS and "NCE-VI-RADS with dDLR" between the two readers. CONCLUSION: NCE-VI-RADS achieved predictive accuracy for muscle invasion comparable to that of conventional VI-RADS. Additional use of dDLR improved the diagnostic accuracy of NCE-VI-RADS. KEY POINTS: • Non-contrast-enhanced Vesical Imaging Reporting and Data System (NCE-VI-RADS) was developed to avoid risk related to gadolinium-based contrast agent administration. • NCE-VI-RADS had predictive accuracy for muscle invasion comparable to that of conventional VI-RADS. • The additional use of denoising deep learning reconstruction (dDLR) might further improve the diagnostic accuracy of NCE-VI-RADS.

Prospective Validation of Vesical Imaging-Reporting and Data System Using a Next-Generation Magnetic Resonance Imaging Scanner-Is Denoising Deep Learning Reconstruction Useful?

PURPOSE: The Vesical Imaging Reporting and Data System (VI-RADS) was launched in 2018 to standardize reporting of magnetic resonance imaging for bladder cancer. This study aimed to prospectively validate VI-RADS using a next-generation magnetic resonance imaging scanner and to investigate the usefulness of denoising deep learning reconstruction. MATERIALS AND METHODS: We prospectively enrolled 98 patients who underwent bladder multiparametric magnetic resonance imaging using a next-generation magnetic resonance imaging scanner before transurethral resection of bladder tumor. Tumors were categorized according to VI-RADS, and we ultimately analyzed 68 patients with pathologically confirmed urothelial bladder cancer. We used receiving operating characteristic curve analyses to assess the predictive accuracy of VI-RADS for muscle invasion. Sensitivity, specificity, positive/negative predictive value, accuracy and area under the curve were calculated for different VI-RADS score cutoffs. RESULTS: Muscle invasion was detected in the transurethral resection of bladder tumor specimens of 18 patients (26%). The optimal cutoff value of the VI-RADS score was determined as ≥4 based on the receiver operating curve analyses. The accuracy of diagnosing muscle invasion using a cutoff of VI-RADS ≥4 was 94% (AUC 0.92). Additionally, we assessed the utility of denoising deep learning reconstruction. Combination with denoising deep learning reconstruction significantly improved the AUC of category by T2-weighted imaging, and of the 4 patients who were misdiagnosed by the final VI-RADS score 3 were correctly diagnosed by T2-weighted imaging+denoising deep learning reconstruction. CONCLUSIONS: In this prospective validation study with a next-generation magnetic resonance imaging scanner, VI-RADS showed high predictive accuracy for muscle invasion in patients with bladder cancer before transurethral resection of bladder tumor. Combining T2-weighted imaging with denoising deep learning reconstruction might further improve the diagnostic accuracy of VI-RADS.

Effect of Ultra High-Resolution Computed Tomography and Model-Based Iterative Reconstruction on Detectability of Simulated Submillimeter Artery.

OBJECTIVE: To evaluate the effect of ultra high-resolution computed tomography (UHRCT) and model-based iterative reconstruction (MBIR) on the detectability of simulated submillimeter artery. METHODS: A small vessel phantom ranging from 0.4 to 2.0 mm in diameter and edge phantoms of low to high attenuation values were scanned by UHRCT (super-high-resolution mode and normal-resolution-mode) and conventional CT, and data were reconstructed by MBIR and filtered back projection (FBP). Vessel detectability was assessed subjectively and the effective size at which 50% of response was achieved (ES50 [mm]) was calculated. Modulation transfer function (MTF) was calculated by an edge spread function method. RESULTS: ES50 of super high-resolution mode (0.36 mm for MBIR and 0.50 mm for FBP) was significantly smaller than those of normal-resolution mode (P < 0.01). In the MTF analysis, the MTF of MBIR improved as the edge phantom attenuation increased, whereas that of FBP was stable. CONCLUSIONS: Both UHRCT and MBIR are effective for the detectability of simulated submillimeter artery.

Additive prognostic significance of ejection fraction for ESC risk model in hypertrophic cardiomyopathy patients.

The European Society of Cardiology (ESC) clinical risk model is reported in predicting sudden death of hypertrophic cardiomyopathy (HCM). We examined the validity of this model and investigated the significance of ejection fraction (EF) in predicting the prognosis using ESC risk model in HCM patients. 305 HCM patients (198 males) were followed (median follow-up 4.8 years) for life-threatening arrhythmic events (sudden death, aborted sudden death, sustained VT/VF, appropriate ICD intervention for VT/VF) and were divided using ESC risk model into low- (Group L), intermediate- (Group I) and high- (Group H) risk groups. There was a significant difference in the events rate among the 3 groups (L, 0.9%/year; I, 3.9%/year; H, 6.8%/year; log-rank p < 0.001) in all study patients. Reduced EF (<50%) was identified in 27 (8.9%) cases. There was a significant difference in the events rate among the 3 groups in patients with reduced EF (L, 2.4%/year; I, 4.9%/year; H, 16.1%/year; log-rank p = 0.025). There was a significant difference in the events rate among 2 groups in patients stratified as Group H (preserved EF, 3.1%/year vs. reduced EF, 16.1%/year; log-rank p = 0.041). ESC risk model precisely predicts life-threatening events in patients with HCM. Adding EF to ESC risk model are useful for further risk stratification of life-threatening arrhythmic events.

High Signal Intensity on T2-Weighted Cardiovascular Magnetic Resonance Imaging Predicts Life-Threatening Arrhythmic Events in Hypertrophic Cardiomyopathy Patients.

BACKGROUND: The prognostic value of high signal intensity on T2-weighted cardiovascular magnetic resonance imaging (T2 high signal) in hypertrophic cardiomyopathy (HCM) patients in a single-center cohort was investigated.Methods and Results:A total of 237 HCM patients (median age, 62 years; 143 male) underwent T2-weighted, cine and late gadolinium enhancement (LGE) imaging, and were followed (median duration, 3.4 years) for life-threatening arrhythmic events. The clinical and magnetic resonance imaging characteristics were extracted, and predictors of life-threatening arrhythmic events were assessed on multivariate analysis. LGE was present in 180 patients (75.9%). Median LGE score was 3 in a left ventricle 17-segment model. T2 high signal was present in 49 patients (20.7%). The annual events rate was significantly higher in patients with extensive LGE (score ≥4) than in those without (3.0%/year vs. 0.5%/year, P=0.011). On multivariate analysis, extensive LGE (hazard ratio, 5.650; 95% CI: 1.263-25.000, P=0.024) as an independent predictor for life-threatening arrhythmic events. In patients with extensive LGE, the annual events rate was significantly higher in patients with T2 high signal than in those without (5.8%/year vs. 0.9%/year, P=0.008). CONCLUSIONS: Extensive LGE was an independent predictor of life-threatening arrhythmic events in HCM patients. Furthermore, T2 high signal is useful for the risk stratification of serious arrhythmic events in patients with extensive LGE.

Preliminary Results: Can Dual-Energy Computed Tomography Help Distinguish Cardiogenic Pulmonary Edema and Acute Interstitial Lung Disease?

OBJECTIVE: We compared iodine concentration in pulmonary ground-glass opacity on iodine density images of contrast-enhanced chest dual-energy computed tomography (DECT) between patients with cardiogenic pulmonary edema (CPE) and acute interstitial lung disease (AILD). METHODS: Five of 12 patients who underwent contrast-enhanced chest DECT to exclude pulmonary embolism were clinically diagnosed with CPE and 7, with AILD. We compared the mean CT value on monochromatic images at 65 keV and iodine concentration on iodine density images between the affected and normal areas. RESULTS: The mean iodine concentrations were comparable between the affected and normal areas (P = 0.3048) in patients with CPE and were significantly higher in the affected than in the normal areas in those with AILD (P < 0.0001). CONCLUSIONS: Measurement of iodine concentration in pulmonary ground-glass opacity of contrast-enhanced chest DECT has the potential to help distinguish CPE and AILD.

Prognostic value of cardiovascular magnetic resonance imaging for life-threatening arrhythmia detected by implantable cardioverter-defibrillator in Japanese patients with hypertrophic cardiomyopathy.

Implantable cardioverter-defibrillator (ICD) is effective to prevent sudden death in HCM patients. We reviewed ICD records to analyze the relation between life-threatening arrhythmia and late gadolinium enhancement (LGE) on cardiovascular magnetic resonance (CMR) in Japanese hypertrophic cardiomyopathy (HCM) patients. In 102 consecutive patients (median age 63 years, 63 males) implanted with an ICD after CMR with gadolinium enhancement (median follow-up 2.8 years), the outcome of life-threatening arrhythmic events (appropriate ICD interventions for ventricular tachycardia or ventricular fibrillation) was examined. Appropriate interventions rate were 10.3% per year for secondary prevention and 7.4% per year for primary prevention. The annualized ICD-related complication rate was 3.7%. 43/91 patients (47%) implanted ICD for primary prevention had maximum wall thickness ≥20 mm plus LGE in ≥4 of 17 left ventricular segments (cut-off value obtained from ROC curve); the appropriate ICD intervention rate was significantly higher in this group than in other patients group (annualized event rate, 11.1 vs. 4.6%; log-rank P = 0.038). A combination of myocardial hypertrophy and LGE is a useful outcome predictive factor for life-threatening ventricular arrhythmia in Japanese HCM patients.

Planimetry of the Orifice Area in Aortic Valve Stenosis Using Phase-Contrast Cardiac Magnetic Resonance Imaging.

Manual planimetry is a well-established method using transesophageal echocardiography (TEE) to assess the severity of aortic stenosis (AS). TEE, however, is a less than optimal approach in patients with calcified valves. Even when using cine-cardiac magnetic resonance (CMR), it is often difficult to evaluate the true border of the aortic orifice because of jet turbulence. With phase-contrast sequences of CMR, high flow signals at the aortic orifice can be clearly visualized, even in cases with severe calcification and jet turbulence. Therefore, the aims of the present study were to compare the utility of CMR using phase-contrast imaging with TEE and cine-CMR for the performance of planimetry of the aortic valve. The study cohort consisted of 30 consecutive patients with moderate or severe aortic valve stenosis documented by TEE who had undergone phase-contrast and cine-CMR for the evaluation of AS. Manual planimetry of the area of high flow signal was traced over the phase-contrast images at systolic peak, when the aortic valve is maximally opened. The results showed that the aortic valvular area (AVA) value derived from TEE correlated better with phase-contrast planimetry (r2 = 0.84, P < 0.05) than cine-mode planimetry (r2 = 0.57, P < 0.05). Bland-Altman plots indicated that the variation of measuring AVA was greater using the cine-mode method than the phase-contrast method. In conclusion, phase-contrast CMR offers a tool for evaluating the severity of aortic valve stenosis noninvasively. Phase-contrast CMR has the potential to become a routine clinical option as an alternative to TEE, at least in selected cases.

Extent of Late Gadolinium Enhancement on Cardiac Magnetic Resonance Imaging in Japanese Hypertrophic Cardiomyopathy Patients.

BACKGROUND: In addition to the presence of late gadolinium enhancement (LGE) on cardiovascular magnetic resonance (CMR), the extent of LGE is considered clinically important in hypertrophic cardiomyopathy (HCM). We evaluated the extent of LGE on CMR in a large series of Japanese HCM patients. METHODS AND RESULTS: CMR was performed in 317 HCM patients (147 male). The extent of LGE was scored as the sum of LGE-positive segments in a left ventricle (LV) 17-segment model. LGE was present in 246 patients (77.6%). LGE was detected in 3.5±3.1 segments on average. When the patients were divided according to maximum wall thickness (mild, <20 mm; moderate, 20-29 mm; severe, ≥30 mm), median LGE score increased as wall thickness increased (mild, 2 vs. moderate, 4 vs. severe, 5; P=0.000). When the patients were divided according to ejection fraction (EF) (reduced, <50%; low-normal, 50-65%; normal, >65%), median LGE score increased as EF decreased (reduced, 7 vs. low-normal, 4 vs. normal, 2; P=0.000). On multivariate analysis, reduced EF (OR, 0.947, P=0.015), pressure gradient <30 mmHg (OR, 0.359, P=0.000) and increased maximum wall thickness (OR, 1.236, P=0.000) were independent factors associated with extensive LGE. CONCLUSIONS: Progression of LGE was related to increased wall thickness, decreased contractility, and reduced intraventricular pressure gradient.

Whole-Body Clinical Applications of Digital Tomosynthesis.

With flat-panel detector mammography, radiography, and fluoroscopy systems, digital tomosynthesis (DT) has been recently introduced as an advanced clinical application that removes overlying structures, enhances local tissue separation, and provides depth information about structures of interest by providing high-quality tomographic images. DT images are generated from projection image data, typically using filtered back-projection or iterative reconstruction. These low-dose x-ray projection images are easily and swiftly acquired over a range of angles during a single linear or arc sweep of the x-ray tube assembly. DT is advantageous in a variety of clinical contexts, including breast, chest, head and neck, orthopedic, emergency, and abdominal imaging. Specifically, compared with conventional mammography, radiography, and fluoroscopy, as a result of reduced tissue overlap DT can improve detection of breast cancer, pulmonary nodules, sinonasal mucosal thickening, and bone fractures and delineation of complex anatomic structures such as the ostiomeatal unit, atlantoaxial joint, carpal and tarsal bones, and pancreatobiliary and gastrointestinal tracts. Compared with computed tomography, DT offers reduced radiation exposure, better in-plane resolution to improve assessment of fine bony changes, and less metallic artifact, improving postoperative evaluation of patients with metallic prostheses and osteosynthesis materials. With more flexible patient positioning, DT is also useful for functional, weight-bearing, and stress tests. To optimize patient management, a comprehensive understanding of the clinical applications and limitations of whole-body DT applications is important for improvement of diagnostic quality, workflow, and cost-effectiveness. Online supplemental material is available for this article. (©)RSNA, 2016.

Dual-Energy Spectral CT: Various Clinical Vascular Applications.

Single-source dual-energy (DE) computed tomography (CT) with fast switching of tube voltage allows projection-based image reconstruction, substantial reduction of beam-hardening effects, reconstruction of accurate monochromatic images and material decomposition images (MDIs), and detailing of material composition by using x-ray spectral information. In vascular applications, DE CT is expected to overcome limitations of standard single-energy CT angiography, including patient exposure to nephrotoxic contrast medium and carcinogenic radiation, insufficient contrast vascular enhancement, interference from metallic and beam-hardening artifacts and severe vessel calcification, and limited tissue characterization and perfusion assessment. Acquisition of low-energy monochromatic images and iodine/water MDIs can reasonably reduce contrast agent dose and improve vessel enhancement. Acquisition of virtual noncontrast images, such as water/iodine MDIs, can reduce overall radiation exposure by replacing true noncontrast CT in each examination. Acquisition of monochromatic images by using metal artifact reduction software or acquisition of iodine/water MDIs can reduce metal artifacts with preserved or increased vessel contrast, and subtraction of monochromatic images between two energy levels can subtract coils composed of dense metallic materials. Acquisition of iodine/calcium (ie, hydroxyapatite) MDIs permits subtraction of vessel calcification and improves vessel lumen delineation. Sensitive detection of lipid-rich plaque can be achieved by using fat/water MDIs, the spectral Hounsfield unit curve (energy level vs CT attenuation), and a histogram of effective atomic numbers included in an image. Various MDIs are useful for accurate differentiation among materials with high attenuation values, including contrast medium, calcification, and fresh hematoma. Iodine/water MDIs are used to assess organ perfusion, such as in the lungs and myocardium. Understanding these DE CT techniques enhances the value of CT for vascular applications. (©)RSNA, 2016.

Current and Novel Imaging Techniques in Coronary CT.

Multidetector coronary computed tomography (CT), which is widely performed to assess coronary artery disease noninvasively and accurately, provides excellent image quality. Use of electrocardiography (ECG)-controlled tube current modulation and low tube voltage can reduce patient exposure to nephrotoxic contrast media and carcinogenic radiation when using standard coronary CT with a retrospective ECG-gated helical scan. Various imaging techniques are expected to overcome the limitations of standard coronary CT, which also include insufficient spatial and temporal resolution, beam-hardening artifacts, limited coronary plaque characterization, and an inability to allow functional assessment of coronary stenosis. Use of a step-and-shoot scan, iterative reconstruction, and a high-pitch dual-source helical scan can further reduce radiation dose. Dual-energy CT can improve contrast medium enhancement and reasonably reduce the contrast dose when combined with noise reduction with the use of iterative reconstruction. High-definition CT can improve spatial resolution and diagnostic evaluation of small or peripheral coronary vessels and coronary stents. Dual-source CT and a motion correction algorithm can improve temporal resolution and reduce coronary motion artifacts. Whole-heart coverage with 320-detector CT and an intelligent boundary registration algorithm can eliminate stair-step artifacts. By decreasing beam hardening and enabling material decomposition, dual-energy CT is expected to remove or reduce the depiction of coronary calcification to improve intraluminal evaluation of calcified vessels and to provide detailed analysis of coronary plaque components and accurate qualitative and quantitative assessment of myocardial perfusion. Fractional flow reserve derived from coronary CT is a state-of-the-art noninvasive technique for accurately identifying myocardial ischemia beyond coronary CT. Understanding these techniques is important to enhance the value of coronary CT for assessment of coronary artery disease.

Diameter measurement of vascular model on CT angiography using model-based iterative reconstruction: effect of tube current on accuracy.

OBJECTIVE: The purpose of this study was to evaluate the effect of tube current on the accuracy of vascular diameter measurements on CT angiography using model-based iterative reconstruction (MBIR). MATERIALS AND METHODS: We constructed a physical phantom composed of nine vascular models of three wall thicknesses filled with contrast material of three densities and scanned the phantom using a 64-MDCT unit with tube currents of 80, 40, 20, and 10 mA. We reconstructed raw data using MBIR and filtered back projection (FBP) algorithms and examined image sharpness by edge rise distance using four tube currents in each of the two reconstruction methods. We measured the mean inner diameter for each model for each set of image data using MBIR with the four tube currents (80, 40, 20, and 10 mA) and FBP with tube current of 80 mA. RESULTS: Sharpness decreased as tube current decreased using MBIR (p < 0.0001) but did not differ significantly among the four tube currents using FBP (p = 0.0506). Sharpness using MBIR with 10 mA tube current was comparable to or significantly worse than that with FBP. The measurement error using MBIR tended to increase as tube current decreased. The measurement errors using MBIR with 10 mA tube current were comparable to or significantly larger than those using FBP for eight of the nine vascular models. CONCLUSION: By decreasing spatial resolution, MBIR with lower tube current can enhance errors in measurement of vascular diameter and should be applied carefully in evaluating vessel diameter.

Prognostic value of late gadolinium enhancement on cardiac magnetic resonance imaging in Japanese hypertrophic cardiomyopathy patients.

BACKGROUND: The prognostic value of late gadolinium enhancement (LGE) on contrast-enhanced cardiovascular magnetic resonance (CMR) in Japanese hypertrophic cardiomyopathy (HCM) patients in a large, single-center cohort was investigated. METHODS AND RESULTS: A total of 345 HCM patients (mean age, 59±17 years; 214 male) underwent CMR with gadolinium enhancement, and were followed (mean duration, 21.8 months) for cardiovascular events. Patients were divided into event-positive and event-negative groups. The clinical and CMR characteristics were compared between the 2 groups, and predictors of cardiovascular events assessed on multivariate analysis. LGE was positive in 252 patients (73%). The annual cardiovascular events rate was significantly higher in patients with LGE than in those without (6.2%/year vs. 0.6%/year, P=0.003). On multivariate analysis, LGE (hazard ratio [HR], 7.436; 95% confidence interval [CI]: 1.001-55.228, P=0.050), increased myocardial mass index (HR, 1.013; 95% CI: 1.002-1.023, P=0.018), reduced left ventricular ejection fraction (HR, 0.965; 95% CI: 0.945-0.985, P=0.001), and atrial fibrillation (HR, 2.257; 95% CI: 1.024-4.976, P=0.043) were significantly associated with cardiovascular events. CONCLUSIONS: The presence of LGE, increased myocardial mass index, reduced left ventricular ejection fraction and atrial fibrillation were independent predictors of adverse prognosis in Japanese HCM patients.

CT of the pancreas: comparison of image quality and pancreatic duct depiction among model-based iterative, adaptive statistical iterative, and filtered back projection reconstruction techniques.

The purpose of this study is to compare CT images of the pancreas reconstructed with model-based iterative reconstruction (MBIR), adaptive statistical iterative reconstruction (ASiR), and filtered back projection (FBP) techniques for image quality and pancreatic duct (PD) depiction. Data from 40 patients with contrast-enhanced abdominal CT [CTDIvol: 10.3 ± 3.0 (mGy)] during the late arterial phase were reconstructed with FBP, 40% ASiR-FBP blending, and MBIR. Two radiologists assessed the depiction of the main PD, image noise, and overall image quality using 5-point scale independently. Objective CT value and noise were measured in the pancreatic parenchyma, and the contrast-to-noise ratio (CNR) of the PD was calculated. The Friedman test and post-hoc multiple comparisons with Bonferroni test following one-way ANOVA were used for qualitative and quantitative assessment, respectively. For the subjective assessment, scores for MBIR were significantly higher than those for FBP and 40% ASiR (all P < 0.001). No significant differences in CT values of the pancreatic parenchyma were noted among FBP, 40% ASiR, and MBIR images (P > 0.05). Objective image noise was significantly lower and CNR of the PD was higher with MBIR than with FBP and 40% ASiR (all P < 0.05). Our results suggest that pancreatic CT images reconstructed with MBIR have lower image noise, better image quality, and higher conspicuity and CNR of the PD compared with FBP and ASiR.

Renal arteriovenous malformation treated using glue embolization under inflow and outflow control by balloon occlusion.

A 45-year-old female presented with gross hematuria. Right renal arteriovenous malformation on abdominal contrast-enhanced computed tomography necessitated urgent transcatheter arterial embolization. Right renal digital subtraction angiography revealed a single tortuous and dilated vessel converging to an aneurysmal dilated vein. To selectively embolize the malformation, we closed the arterial side with a microballoon and attempted glue embolization; filling occurred unexpectedly early, and another balloon on the vein side helped control the renal vein blood flow. Glue embolization was performed without adverse events. Glue embolization for high-flow arteriovenous malformation under balloon occlusion-mediated inflow and outflow control can effectively and safely embolize complete target vessels.

Comparison of the diagnostic and prognostic abilities of flexible laryngoscopy and dynamic digital radiography for vocal cord paralysis: A prospective observational study.

BACKGROUND: Although flexible laryngoscopy (FL) is the reference modality for diagnosing vocal cord paralysis (VCP), FL involves patient discomfort and insertion intolerance. Dynamic digital radiography (DDR) with high spatial and temporal resolution is easier to use and less invasive when evaluating VCP. METHODS: Seventy-eight patients underwent FL and DDR before and after neck surgery. Qualitative and quantitative vocal cord movement (VCM) evaluations were conducted. Patients with postoperative VCP were followed-up regularly. RESULTS: DDR exhibited diagnostic performance with 67% sensitivity and 100% specificity. The cutoff for VCM was 2.4 mm, with DDR exhibiting 100% sensitivity and 78% specificity. All cords with transient VCP had positive VCM at both 3 weeks and 2 months. Additionally, 50% and 75% of cords with permanent VCP had negative VCM at 3 weeks and 2 months, respectively. CONCLUSIONS: DDR is promising for the diagnosis of postoperative VCP and early prediction of permanent postoperative VCP.

Vascular diameter measurement in CT angiography: comparison of model-based iterative reconstruction and standard filtered back projection algorithms in vitro.

OBJECTIVE: The purpose of this study was to evaluate the performance of model-based iterative reconstruction (MBIR) in measurement of the inner diameter of models of blood vessels and compare performance between MBIR and a standard filtered back projection (FBP) algorithm. MATERIALS AND METHODS: Vascular models with wall thicknesses of 0.5, 1.0, and 1.5 mm were scanned with a 64-MDCT unit and densities of contrast material yielding 275, 396, and 542 HU. Images were reconstructed images by MBIR and FBP, and the mean diameter of each model vessel was measured by software automation. Twenty separate measurements were repeated for each vessel, and variance among the repeated measures was analyzed for determination of measurement error. For all nine model vessels, CT attenuation profiles were compared along a line passing through the luminal center on axial images reconstructed with FBP and MBIR, and the 10-90% edge rise distances at the boundary between the vascular wall and the lumen were evaluated. RESULTS: For images reconstructed with FBP, measurement errors were smallest for models with 1.5-mm wall thickness, except those filled with 275-HU contrast material, and errors grew as the density of the contrast material decreased. Measurement errors with MBIR were comparable to or less than those with FBP. In CT attenuation profiles of images reconstructed with MBIR, the 10-90% edge rise distances at the boundary between the lumen and vascular wall were relatively short for each vascular model compared with those of the profile curves of FBP images. CONCLUSION: MBIR is better than standard FBP for reducing reconstruction blur and improving the accuracy of diameter measurement at CT angiography.