The Feasibility of Deep Learning-Based Reconstruction for Low-Tube-Voltage CT Angiography for Transcatheter Aortic Valve Implantation.

OBJECTIVE: The purpose of this study is to evaluate the efficacy of deep learning reconstruction (DLR) on low-tube-voltage computed tomographic angiography (CTA) for transcatheter aortic valve implantation (TAVI). METHODS: We enrolled 30 patients who underwent TAVI-CT on a 320-row CT scanner. Electrocardiogram-gated coronary CTA (CCTA) was performed at 100 kV, followed by nongated aortoiliac CTA at 80 kV using a single bolus of contrast material. We used hybrid-iterative reconstruction (HIR), model-based IR (MBIR), and DLR to reconstruct these images. The contrast-to-noise ratios (CNRs) were calculated. Five-point scales were used for the overall image quality analysis. The diameter of the aortic annulus was measured in each reconstructed image, and we compared the interobserver and intraobserver agreements. RESULTS: In the CCTA, the CNR and image quality score for DLR were significantly higher than those for HIR and MBIR ( P < 0.01). In the aortoiliac CTA, the CNR for DLR was significantly higher than that for HIR ( P < 0.01) and significantly lower than that for MBIR ( P ≤ 0.02). The image quality score for DLR was significantly higher than that for HIR ( P < 0.01). No significant differences were observed between the image quality scores for DLR and MBIR. The measured aortic annulus diameter had high interobserver and intraobserver agreement regardless of the reconstruction method (all intraclass correlation coefficients, >0.89). CONCLUSIONS: In low tube voltage TAVI-CT, DLR provides higher image quality than HIR, and DLR provides higher image quality than MBIR in CCTA and is visually comparable to MBIR in aortoiliac CTA.

Refined scan protocol for the evaluation of pulmonary perfusion standardized image quality and reduced radiation dose in dynamic chest radiography.

PURPOSE: Dynamic chest radiography (DCR) is a novel imaging technique used to noninvasively evaluate pulmonary perfusion. However, the standard DCR protocol, which is roughly adapted to the patient's body size, occasionally causes over- or underexposure, which could influence clinical evaluation. Therefore, we proposed a refined protocol by increasing the number of patient body mass index (BMI) categories from three to seven groups and verified its usefulness by comparing the image sensitivity indicators (S-values) and entrance surface doses (ESDs) of the conventional protocol with those of our refined protocol. METHODS: This retrospective observational study included 388 datasets (standing position, 224; supine position, 164) for the conventional protocol (December 2019-April 2021) and 336 datasets (standing position, 233; supine position, 103) for the refined protocol (June-November 2021). The conventional protocol (BMI-3 protocol) divided the patients into three BMI groups (BMI < 17, 17≤BMI < 25, and BMI ≥ 25 kg/m2 ), whereas the refined protocol (BMI-7 protocol) divided the patients into seven BMI groups (BMI < 17, 17 ≤ BMI < 20, 20 ≤ BMI < 23, 23 ≤ BMI < 26, 26 ≤ BMI < 29, 29 ≤ BMI < 32, and BMI ≥ 32 kg/m2 ). The coefficients of variation (CVs) for the S-values and ESDs acquired using the two protocols were compared. RESULTS: The CVs of the S-values in the BMI-7 protocol group were significantly lower than those in the BMI-3 protocol group for the standing (28.8% vs. 16.7%; p < 0.01) and supine (24.5% vs. 17.7%; p < 0.01) positions. The ESDs of patients scanned using the BMI-7 protocol were significantly lower than those scanned using the BMI-3 protocol in the standing (1.3 vs. 1.1 mGy; p < 0.01) and supine positions (2.5 vs. 1.6 mGy; p < 0.01), although the mean BMI of the two groups were similar. CONCLUSION: We introduced the BMI-7 protocol and demonstrated its standardized image quality and reduced radiation exposure in patients undergoing DCR.

Efficacy of Dynamic Chest Radiography for Chronic Thromboembolic Pulmonary Hypertension.

Background While current guidelines require lung ventilation-perfusion (V/Q) scanning as the first step to diagnose chronic pulmonary embolism in pulmonary hypertension (PH), its use may be limited by low availability and/or exposure to ionizing radiation. Purpose To compare the performance of dynamic chest radiography (DCR) and lung V/Q scanning for detection of chronic thromboembolic PH (CTEPH). Materials and Methods Patients with PH who underwent DCR and V/Q scanning in the supine position from December 2019 to July 2021 were retrospectively screened. The diagnosis of CTEPH was confirmed with right heart catheterization and invasive pulmonary angiography. Observer tests were conducted to evaluate the diagnostic accuracy of DCR and V/Q scanning. The lungs were divided into six areas (upper, middle, and lower for both) in the anteroposterior image, and the number of lung areas with thromboembolic perfusion defects was scored. Diagnostic performance was compared between DCR and V/Q scanning using the area under the receiver operating characteristic curve. Agreement between the interpretation of DCR and that of V/Q scanning was assessed using the Cohen kappa coefficient and percent agreement. Results A total of 50 patients with PH were analyzed: 29 with CTEPH (mean age, 64 years ± 15 [SD]; 19 women) and 21 without CTEPH (mean age, 61 years ± 22; 14 women). The sensitivity, specificity, and accuracy of DCR were 97%, 86%, and 92%, respectively, and those of V/Q scanning were 100%, 86%, and 94%, respectively. Areas under the receiver operating characteristic curve for DCR and V/Q scanning were 0.92 (95% CI: 0.79, 0.97) and 0.93 (95% CI: 0.78, 0.98). Agreement between the consensus interpretation of DCR and that of V/Q scanning was substantial (κ = 0.79 [95% CI: 0.61, 0.96], percent agreement = 0.9 [95% CI: 0.79, 0.95]). Conclusion Dynamic chest radiography had similar efficacy to ventilation-perfusion scanning in the detection of chronic thromboembolic pulmonary hypertension. © RSNA, 2022 Online supplemental material is available for this article. See also the editorial by Wandtke and Koproth-Joslin in this issue.

Rotational head acceleration and traumatic brain injury in combat sports: a systematic review.

BACKGROUND: Traumatic brain injury (TBI) in combat sports is relatively common, and rotational acceleration (RA) is a strong biomechanical predictor of TBI. This review summarizes RA values generated from head impacts in combat sport and puts them in the context of present evidence regarding TBI thresholds. SOURCES OF DATA: PubMed, EMBASE, Web of Science, Cochrane Library and Scopus were searched from inception to 31st December 2021. Twenty-two studies presenting RA data from head impacts across boxing, taekwondo, judo, wrestling and MMA were included. The AXIS tool was used to assess the quality of studies. AREAS OF AGREEMENT: RA was greater following direct head strikes compared to being thrown or taken down. RA from throws and takedowns was mostly below reported injury thresholds. Injury thresholds must not be used in the absence of clinical assessment when TBI is suspected. Athletes displaying signs or symptoms of TBI must be removed from play and medically evaluated immediately. AREAS OF CONTROVERSY: Methodological heterogeneity made it difficult to develop sport-specific conclusions. The role of headgear in certain striking sports remains contentious. GROWING POINTS: RA can be used to suggest and assess the effect of safety changes in combat sports. Gradual loading of training activities based on RA may be considered when planning sessions. Governing bodies must continue to work to minimize RA generated from head impacts. AREAS TIMELY FOR DEVELOPING RESEARCH: Prospective research collecting real-time RA data is required to further understanding of TBI in combat sports.

Right Ventricular Extracellular Volume with Dual-Layer Spectral Detector CT: Value in Chronic Thromboembolic Pulmonary Hypertension.

Background Right ventricular (RV) extracellular volumes (ECVs), as a surrogate for histologic fibrosis, have not been sufficiently investigated. Purpose To evaluate and compare RV and left ventricular (LV) ECVs obtained with dual-layer spectral detector CT (DLCT) in chronic thromboembolic pulmonary hypertension (CTEPH) and investigate the clinical importance of RV ECV. Materials and Methods Retrospective analysis was performed on data from 31 patients with CTEPH (17 were not treated with pulmonary endarterectomy [PEA] or balloon pulmonary angioplasty [BPA] and 14 were) and eight control subjects who underwent myocardial delayed enhancement (MDE) DLCT from January 2019 to June 2020. The ECVs in the RV and LV walls were calculated by using iodine density as derived from spectral data pertaining to MDE. Statistical analyses were performed with one-way repeated analysis of variance with the Tukey post hoc test or the Kruskal-Wallis test with the Steel-Dwass test and linear regression analysis. Results The PEA- and BPA-naive group showed significantly higher ECVs than the PEA- or BPA-treated group and control group in the septum (28.2% ± 2.9 vs 24.3% ± 3.6, P = .005), anterior right ventricular insertion point (RVIP) (32.9% ± 4.6 vs 25.3% ± 3.6, P < .001), posterior RVIP (35.2% ± 5.2 vs 27.3% ± 4.2, P < .001), mean RVIP (34.0% ± 4.2 vs 26.3% ± 3.4, P < .001), RV free wall (29.5% ± 3.3 vs 25.9% ± 4.1, P = .036), and mean RV wall (29.1% ± 3.0 vs 26.1% ± 3.1, P = .029). There were no significant differences between the PEA- or BPA-treated group and control subjects in these segments (septum, P = .93; anterior RVIP, P = .38; posterior RVIP, P = .52; mean RVIP, P = .36; RV free wall, P = .97; and mean RV, P = .33). There were significant correlations between ECV and mean pulmonary artery pressure (PAP) or brain natriuretic peptide (BNP) in the mean RVIP (mean PAP: R = 0.66, P < .001; BNP: R = 0.44, P = .014) and the mean RV (mean PAP: R = 0.49, P = .005; BNP: R = 0.44, P = .013). Conclusion Right ventricular and right ventricular insertion point extracellular volumes could be noninvasive surrogate markers of disease severity and reverse tissue remodeling in chronic thromboembolic pulmonary hypertension. © RSNA, 2021 Online supplemental material is available for this article. See also the editorial by Sandfort and Bluemke in this issue.

Characterization of parotid gland tumors: added value of permeability MR imaging to DWI and DCE-MRI.

OBJECTIVES: To determine added value of permeability MRI in parotid tumor characterization to T2-weighted imaging (T2WI), semi-quantitative analysis of time-intensity curve (TIC), and intra-voxel incoherent motion diffusion-weighted imaging (IVIM-DWI). METHODS: This retrospective study was approved by the institutional review board, and the informed consent was waived. Sixty-one parotid tumors in 61 patients were examined using T2WI, IVIM-DWI, and permeability MRI. TIC patterns were categorized as persistent, washout, or plateau. Signal intensity ratio of lesion-to-muscle on T2WI, apparent diffusion coefficients (ADCs), D and f values from IVIM-DWI, and Ktrans, kep, Ve, and Vp values from permeability MRI were measured. Multiple comparisons were applied to determine whether any differences among 4 histopathologic types (pleomorphic adenomas, Warthin's tumors, other benign tumors, and malignant tumors) existed. Diagnostic accuracy was compared before and after modification diagnosis referring to permeability MRI. In a validation study, 60 parotid tumors in 60 patients were examined. RESULTS: ADC and D values of malignant tumors were significantly lower than those of benign tumors other than Warthin's tumors, but higher than those of Warthin's tumors. kep and Vp values of Warthin's tumors were significantly higher than those of malignant tumors. Multivariate analyses showed that TIC pattern, D, and kep values were suitable parameters. McNemar's test showed a significant increase of sensitivity (11/12, 92%) and specificity (46/49, 94%) with adding kep. The validation study yielded high sensitivity (14/16, 88%) and specificity (41/44, 93%). CONCLUSION: Permeability MRI offers added value to IVIM-MRI and semi-quantitative TIC analysis of DCE-MRI in characterization of parotid tumors KEY POINTS: • Permeability MR imaging offers added value in the characterization of parotid gland tumors in combination with semi-quantitative TIC analysis and IVIM analyses with D parameter. • The combination of TIC pattern, D, and kep might facilitate accurate characterization of parotid gland tumor, thereby avoiding unnecessary surgery for benign tumors or delayed treatment for malignant tumors. • A combination of permeability and diffusion MR imaging can be used to guide the selection of an appropriate biopsy site.

Low Radiation Dose and High Image Quality of 320-Row Coronary Computed Tomography Angiography Using a Small Dose of Contrast Medium and Refined Scan Timing Prediction.

OBJECTIVE: The aim of the study was to investigate the feasibility of coronary computed tomography (CT) angiography with a low kilovoltage peak scan and a refined scan timing prediction using a small contrast medium (CM) dose. METHODS: In protocol A, 120-kVp scanning and a standard CM dose were used. The scan timing was fixed. In protocol B, 80 kVp and a 60% CM dose were used. The scan timing was determined according to the interval from the CM arrival to the peak time in the ascending aorta. We measured the CT number and recorded the radiation dose. RESULTS: Higher CT numbers were observed in the left circumflex (proximal, P = 0.0235; middle, P = 0.0007; distal, P < 0.0001) in protocol B compared with protocol A. The radiation dose in protocol B was significantly lower than in protocol A (2.2 ± 0.9 vs 4.3 ± 1.7 mSv). CONCLUSIONS: Low-contrast, low-radiation dose, high-image quality coronary CT angiography can be performed with low kilovoltage peak scanning and a refined scan timing prediction.

Correction to: Development of a new phantom simulating extracellular space of tumor cell growth and cell edema for diffusion-weighted magnetic resonance imaging.

The original version of this article unfortunately contained a mistake. Second column of "Cell edema" should read as.

The reproducibility of measurements using a standardization phantom for the evaluation of fractional anisotropy (FA) derived from diffusion tensor imaging (DTI).

OBJECTIVES: It is necessary to standardize the examination procedure and diagnostic criteria of diffusion tensor imaging (DTI). Thus, the purpose of this study was to examine the reproducibility of measurements using a standardization phantom composed of different fibre materials with different fibre densities (FDs) for the evaluation of fractional anisotropy (FA) derived from DTI. MATERIALS AND METHODS: Two types of fibre materials wrapped in heat-shrinkable tubes were used as fibre phantoms. We designed fibre phantoms with three different FDs of each fibre material. The standardization phantom was examined using DTI protocol six times a day, and each examination session was repeated once a month for 7 consecutive months. Fibre tracking was performed by setting regions of interest in the FA map, and FA was measured in each fibre phantom. Coefficients of variation (CVs) were used to evaluate the inter-examination reproducibility of FA values. Furthermore, Bland-Altman plots were used to evaluate the intra-operator reproducibility of FA measurements. RESULTS: All CVs for each fibre phantom were within 2% throughout the 7-month study of repeated DTI sessions. The high intra-operator reproducibility of the FA measurement was confirmed. DISCUSSION: High reproducibility of measurements using a standardization phantom for the evaluation of FA was achieved.

Development of a new phantom simulating extracellular space of tumor cell growth and cell edema for diffusion-weighted magnetic resonance imaging.

OBJECTIVE: A phantom for diffusion-weighted imaging is required to standardize quantitative evaluation. The objectives were to develop a phantom simulating various cell densities and to evaluate repeatability. MATERIALS AND METHODS: The acrylic fine particles with three different diameters were used to simulate human cells. Four-degree cell density components were developed by adjusting the volume of 10-µm particles (5, 20, 35, and 50% volume, respectively). Two-degree components to simulate cell edema were also developed by adjusting the diameter without changing number (17% and 40% volume, respectively). Spearman's rank correlation coefficient was used to find a significant correlation between apparent diffusion coefficient (ADC) and particle density. Coefficient of variation (CV) for ADC was calculated for each component for 6 months. A p value < 0.05 represented a statistically significance. RESULTS: Each component (particle ratio of 5, 17, 20, 35, 40, and 50% volume, respectively) presented ADC values of 1.42, 1.30, 1.30, 1.12, 1.09, and 0.89 (× 10-3 mm2/s), respectively. A negative correlation (r = - 0.986, p < 0.05) was observed between ADC values and particle ratio. CV for ADC was less than 5%. DISCUSSION: A phantom simulating the diffusion restriction correlating with cell density and size could be developed.

Clinical usefulness of right ventricular 3D area strain in the assessment of treatment effects of balloon pulmonary angioplasty in chronic thromboembolic pulmonary hypertension: comparison with 2D feature-tracking MRI.

OBJECTIVES: To evaluate the usefulness of right ventricular (RV) area strain analysis via cardiac MRI (CMRI) as a tool for assessing the treatment effects of balloon pulmonary angioplasty (BPA) in inoperable chronic thromboembolic pulmonary hypertension (CTEPH), RV area strain was compared to two-dimensional (2D) strain with feature-tracking MRI (FTMRI) before and after BPA. METHODS: We retrospectively analyzed 21 CTEPH patients who underwent BPA. End-systolic global area strain (GAS), longitudinal strain (LS), circumferential strain (CS), and radial strain (RS) were measured before and after BPA. Changes in GAS and RV ejection fraction (RVEF) values after BPA were defined as ΔGAS and ΔRVEF. Receiver operating characteristic (ROC) analyses were performed to determine the optimal cutoff of the strain at after BPA for detection of improved patients with decreased mean pulmonary artery pressure (mPAP) less than 30 mmHg and increased RVEF more than 50%. RESULTS: ROC analysis revealed the optimal cutoffs of strains (GAS, LS, CS, and RS) for identifying improved patients with mPAP < 30 mmHg (cutoff (%) = - 41.2, - 13.8, - 16.7, and 14.4: area under the curve, 0.75, 0.56, 0.65, and 0.75) and patients with RVEF > 50% (cutoff (%) = - 37.2, - 29.5, - 2.9, and 14.4: area under the curve, 0.81, 0.60, 0.56, and 0.56). CONCLUSIONS: Area strain analysis via CMRI may be a more useful tool for assessing the treatment effects of BPA in patients with CTEPH than 2D strains with FTMRI. KEY POINTS: • Area strain values can detect improvement of right ventricular (RV) pressure and function after balloon pulmonary angioplasty (BPA) equally or more accurately than two-dimensional strains. • Area strain analysis is a useful analytical method that reflects improvements in complex RV myocardial deformation by BPA. • Area strain analysis is a robust method with reproducibility equivalent to that of 2D strain analysis.

Evaluation of humeral head cartilage using magnetic resonance imaging T1 rho mapping for patients with small-to-medium rotator cuff tears: A pilot study.

BACKGROUND: It is unclear whether smaller rotator cuff tears cause cartilage degeneration. This study was designed to detect early humeral head cartilage degeneration in patients with small-to-medium cuff tears using magnetic-resonance-imaging T1 rho mapping. METHODS: Five male and 5 female volunteers without shoulder symptoms (control group) and 5 male and 5 female patients with small-to-medium (<3 cm) rotator cuff tears underwent 3.0-T magnetic resonance imaging of a single shoulder. T1 rho values of the humeral head cartilage were measured and analyzed. RESULTS: The total mean T1 rho value was 40.4 ± 3.4 ms for the control group and 45.0 ± 5.3 ms for the patient group. In the control group, the T1 rho values in the inferior articular cartilage were significantly higher than those in the superior and middle articular cartilage. In the patient group, there was no significant difference between all regions. A comparison between the patient and control groups showed that the mean T1 rho values in the superior-to-middle articular cartilage were significantly higher for the patient group than for the control group. However, in the inferior articular cartilage, there was no significant difference between both groups. CONCLUSIONS: This study showed the possibility of early cartilage degenerative changes in the superior-to-middle humeral head articular cartilage of patients with small-to-medium rotator cuff tears.

Prediction of Therapeutic Effect of Chemotherapy for NSCLC Using Dual-Input Perfusion CT Analysis: Comparison among Bevacizumab Treatment, Two-Agent Platinum-based Therapy without Bevacizumab, and Other Non-Bevacizumab Treatment Groups.

Purpose To determine whether dual-input perfusion computed tomography (CT) can predict therapeutic response and prognosis in patients who underwent chemotherapy for non-small cell lung cancer (NSCLC). Materials and Methods The institutional review board approved this study and informed consent was obtained. Sixty-six patients with stage III or IV NSCLC (42 men, 24 women; mean age, 63.4 years) who underwent chemotherapy were enrolled. Patients were separated into three groups: those who received chemotherapy with bevacizumab (BV) (n = 20), those who received two-agent platinum-based therapy without BV (n = 25), and those who received other non-BV treatment (n = 21). Before treatment, pulmonary artery perfusion (PAP) and bronchial artery perfusion (BAP) of the tumors were calculated. Predictors of tumor reduction after two courses of chemotherapy and prognosis were identified by using univariate and multivariate analyses. Covariates included were age, sex, patient's performance status, baseline maximum diameter of the tumor, clinical stage, pretreatment PAP, and pretreatment BAP. For multivariate analyses, multiple linear regression analysis for tumor reduction rate and Cox proportional hazards model for prognosis were performed, respectively. Results Pretreatment BAP was independently correlated with tumor reduction rate after two courses of chemotherapy in the BV treatment group (P = .006). Pretreatment BAP was significantly associated with a highly cumulative risk of death (P = .006) and disease progression after chemotherapy (P = .015) in the BV treatment group. Pretreatment PAP and clinical parameters were not significant predictors of therapeutic effect or prognosis in three treatment groups. Conclusion Pretreatment BAP derived from dual-input perfusion CT seems to be a promising tool to help predict responses to chemotherapy with BV in patients with NSCLC. © RSNA, 2017.

Comparison of intravoxel incoherent motion diffusion-weighted imaging between turbo spin-echo and echo-planar imaging of the head and neck.

OBJECTIVES: To compare image quality, apparent diffusion coefficient (ADC), and intravoxel incoherent motion (IVIM)-derived parameters between turbo spin-echo (TSE)-diffusion-weighted imaging (DWI) and echo-planar imaging (EPI)-DWI of the head and neck. METHODS: Fourteen volunteers underwent head and neck imaging using TSE-DWI and EPI-DWI. Distortion ratio (DR), signal-to-noise ratio (SNR), contrast-to-noise ratio (CNR), ADC and IVIM-derived parameters were compared between the two techniques. Bland-Altman analysis was performed to analyse reproducibility between the quantitative parameters of TSE-DWI and EPI-DWI. RESULTS: DR of TSE-DWI was significantly smaller than that of EPI-DWI. SNR and CNR of TSE-DWI were significantly higher than those of EPI-DWI. ADC and IVIM-derived parameters of TSE-DWI showed higher values than those of EPI-DWI, although the difference was not significant. Bland-Altman analysis showed wide limits of agreement between the two sequences. CONCLUSION: TSE-DWI can produce better image quality than EPI-DWI, while TSE-DWI possibly exhibits different values of quantitative parameters. Therefore, TSE-DWI could be a good alternative to EPI-DWI for patients sensitive to distortion. However, it is not recommended to use both TSE-DWI and EPI-DWI on follow-up. KEY POINTS: • Head and neck DWI is especially sensitive to magnetic inhomogeneity. • The distortion of images was less with TSE-DWI than with EPI-DWI. • TSE-DWI can possibly exhibit higher ADC and IVIM-derived parameters than EPI-DWI. • Bland-Altman analysis showed unacceptable LoA in quantitative analysis between TSE-DWI and EPI-DWI. • It is not recommended to use both TSE-DWI and EPI-DWI for follow-up.

One-stop shop assessment for atrial septal defect closure using 256-slice coronary CT angiography.

OBJECTIVES: To investigate the feasibility and accuracy of measurement of the pulmonary to systemic blood flow ratio (Qp/Qs) and defect and rim sizes in secundum atrial septal defects (ASDs) using 256-slice CT, compared to the reference transoesophageal echocardiography (TEE) and right heart catheterization (RHC) measurements. METHODS: Twenty-three consecutive adult patients with secundum ASDs who underwent retrospective ECG-gated coronary CT angiography (CCTA), TEE and RHC were enrolled in this study. Right ventricular (RV) and left ventricular (LV) stroke volumes (SV) were calculated by biventricular volumetry of CCTA. Qp/Qs-CT was defined as RVSV/LVSV. The sizes of the defect and rim were measured by multi-planar reconstruction CT images. Correlations between Qp/Qs-CT and Qp/Qs-RHC and between the defect diameter obtained by CT and TEE were analyzed by Pearson's coefficient analysis. Rim sizes by CT and TEE were compared by paired t-test. RESULTS: Qp/Qs-CT was significantly correlated with Qp/Qs-RHC (r = 0.83, p < 0.0001), and the defect diameter by CT was significantly correlated with that by TEE (r = 0.95, p < 0.0001). There was no significant difference between CT and TEE in measurements of rim size. CONCLUSIONS: 256-slice CCTA allows measuring Qp/Qs and size of defects and rims in patients with secundum ASDs, accomplishing pretreatment evaluation non-invasively and comprehensively. KEY POINTS: • Quantification of left-to-right shunting can be performed reliably and accurately by CT. • The sizes of defects and rims can be measured accurately using 256-slice CT. • 256-slice CT permits pretreatment evaluation of ASD non-invasively and comprehensively.

Geometrical characteristics of aortic root and left ventricular dysfunction in aortic stenosis: quantification of 256-slice coronary CT angiography.

The purpose of this study is to analyze the geometrical characteristics of aortic root and left ventricular (LV) function in aortic stenosis (AS) using 256-slice coronary-computed tomography angiography (CCTA). Retrospective ECG-gated 256-slice CCTA data from 32 patients with tricuspid AS scheduled for aortic valve replacement, and 11 controls were analyzed. Aortic root geometry was measured using multiplanar reconstruction CT images. CCTA data set was transformed into 100 phases/cycle using motion coherence image processing. Systolic shortening (SS, mm/ms) and diastolic relaxation (DR, mm/ms2) in the circumferential and longitudinal directions on time curves of myocardial length were calculated, and were used as estimates of geometric LV function. Comparison of parameters was analyzed by Mann-Whitney U test. Receiver-operating-characteristic (ROC) analysis was performed to determine the optimal cutoff of parameters for differentiating AS patients. Height of the right coronary cusp was significantly lower for AS patients than controls (11.4 ± 2.4 vs. 13.9 ± 2.0 mm/m2, p < 0.005). Vertical-longitudinal SS was significantly lower for AS patients than for controls (1.7 ± 0.8 vs. 2.7 ± 0.7 mm/ms/m2, p < 0.001). ROC analysis revealed optimal height of the right coronary cusp of 12.4 mm/m2 and vertical-longitudinal SS of 2.4 mm/ms/m2 for differentiating AS patients from controls, with C statistics of 0.82 and 0.85. In AS patients, ROC analysis revealed optimal vertical-longitudinal DR of 0.05 mm/ms2/m2 for predicting patients with stroke volume index <35 ml with C statistics of 0.93. Quantification of CCTA demonstrates that AS is characterized by small coronary cusps as aortic root remodeling and vertical-longitudinal LV dysfunction related to restrictive physiology.

Detectability of BI-RADS category 3 or higher breast lesions and reading time on mammography: comparison between 5-MP and 8-MP LCD monitors.

Background Five-megapixel (MP) displays are recommended as soft copy devices for digital mammogram. An 8-MP liquid crystal display (LCD) (two 4-MP displays within one display) might offer the advantage of being able to view biplane mammography more easily than the dual planes of 5-MP LCDs. Purpose To compare detectability of Breast Imaging Reporting and Data System (BI-RADS) category 3 or higher lesions and reading time on mammography between 5- MP and 8-MP LCDs. Material and Methods The mammograms of 240 breasts of 120 patients including 60 breasts with BI-RADS category 3 or higher lesions and 180 breasts with normal or category 2 lesions were enrolled. All bilateral mammograms were displayed on bifacial 5-MP LCDs or an 8-MP LCD (two 4-MP displays within one display). Six radiologists assessed 240 breasts on each display. The observations were analyzed using receiver operating characteristic (ROC) analysis. A jack-knife method was used for statistical analysis. We employed a paired t-test to determine whether any significant differences existed in the reading time between two different displays. A P value < 0.05 was considered significant. Results The mean areas under the ROC curve obtained using 5-MP and 8-MP LCDs were 0.925 and 0.915, respectively, and there was no significant difference ( P = 0.46). There was also no significant difference in the reading time between two types of displays (57.8 min. vs. 51.5 min, P = 0.39). Conclusion The detectability of BI-RADS category 3 or higher lesions and reading time using an 8-MP LCD were comparable to those using a 5-MP LCD.

Clinical impact of left ventricular eccentricity index using cardiac MRI in assessment of right ventricular hemodynamics and myocardial fibrosis in congenital heart disease.

OBJECTIVES: To investigate the utility of eccentricity index (EI) using cardiac cine MRI for the assessment of right ventricular (RV) hemodynamics in congenital heart disease (CHD). METHODS: Fifty-five patients with CHD (32 women; mean age, 40.7 ± 20.9 years) underwent both cardiac MRI and right heart catheterization. EI was defined as the ratio of the distance between the anterior-posterior wall and the septal-lateral wall measured in the short-axis of mid-ventricular cine MRI. Correlations between EIs and RV hemodynamic parameters were analyzed. EIs were compared between patients with and without late gadolinium enhancement (LGE). RESULTS: A strong correlation between mean pulmonary artery pressure (PAP) and systolic EI (r = 0.81, p < 0.0001) and a moderate negative correlation between diastolic EI and RV ejection fraction (EF) (r = -0.62, p < 0.0001) were observed. Receiver operating characteristic analysis revealed optimal EI thresholds for detecting patients with mean PAP ≥40 mmHg with C-statistics of 0.90 and patients with RVEF <40 % with C-statistics of 0.78. Systolic EIs were significantly greater for patients with LGE (1.45 ± 0.05) than for those without LGE (1.15 ± 0.07; p < 0.001). CONCLUSIONS: EI offers a simple, comprehensive index that can predict pulmonary hypertension and RV dysfunction in CHD. KEY POINTS: • EI offers a simple and comprehensive index of RV hemodynamics. • EI could predict pulmonary hypertension and RV dysfunction. • Left ventricular deformation expressed as high EI is related to myocardial fibrosis.