A fast and reproducible method to estimate left atrial volume using cardiac computed tomography.

PURPOSE: The purpose of this study was to do better than the simple maximal axial area (MAreaax) and to validate simple, fast and robust orthogonal methods for determining the left atrium volume (LAV) with cardiac CT (CCT). MATERIAL AND METHODS: A total of 60 patients who underwent CTT were retrospectively included. There were 30 men and 30 women with a mean age of 59±12 (SD) years (range: 27-80 years), using four methods to assess LAV beyond the MAreaax: two orthogonal methods requiring the measurements of axial, coronal and sagittal planes of 3 diameters LAV3diam or 3 area LAV3Areas; Area-length biplane method LAVbiplane; and volumetric method LAVvolumetric using a semi-automated tool that served as the reference standard. The orthogonal methods were applied on contrast-enhanced (IV+) and unenhanced (IV-) CCT images. Comparisons were performed using Pearson correlation test (r) and Bland-Altman analysis. Inter- and intra-observer variability were assessed using intraclass correlation coefficient (ICC) with a two-way mixed-effects model. RESULTS: On IV+ CCT, LAVbiplane, LAV3diam-IV+, LAV3Areas-IV+ underestimated LAV (-15±1.99mL; -21±1.37mL; -15±1.98mL; all P<0.001). LAV3diam-IV+, LAV3Areas-IV+ better correlated with reference standard (r=0.97 and 0.98) than LAVbiplane (r=0.79) as well as MAreaax (r=0.90). Estimating LAV on IV- further showed high correlation against the reference (r=0.93 and 0.95 for LAV3diam-IV- and LAV3Areass-IV-, respectively). Intra- and inter-observer ICC increased from LAVvolumetric (2.43% and 3.09%); LAV3Areas-IV+ (3.04 and 3.30%); LAV3Areas-IV-(3.34 and 4.23%), LAV3diam-IV+ (3.36 and 5.11%); LAV3diam-IV- (5.16 and 6.90%); to LAVbiplane (9.65 and 10.28%). CONCLUSIONS: Better than MAreaax, orthogonal methods using either diameter or surface are fast and reproducible methods to assess LAV on CCT when performed with or without intravenous administration of contrast material.

Neopulmonary Outflow Tract Obstruction Assessment by 4D Flow MRI in Adults With Transposition of the Great Arteries After Arterial Switch Operation.

BACKGROUND: The main complication in adult patients with transposition of the great arteries (TGA) treated by an arterial switch operation (ASO) is neopulmonary outflow tract stenosis (NPOTS). However, pulmonary flow velocity measurements cannot always be performed with transthoracic echocardiography (TTE) due to complex anatomical features. 4D flow MRI allows detection, quantification, and location of the obstruction site along the NPOTS. PURPOSE AND HYPOTHESIS: To investigate the accuracy of 4D flow for the diagnosis of NPOTS in adults with TGA corrected by ASO. STUDY TYPE: Prospective. POPULATION: Thirty-three adult patients with TGA treated by ASO (19 men, mean age 25.5 years old). FIELD STRENGTH/SEQUENCE: Accelerated 4D flow research sequence at 3T. ASSESSMENT: Maximum NPOTS velocities on TTE and 4D flow MRI done the same day. STATISTICAL TESTS: Pearson correlation coefficient, paired t-test, and Bland-Altman analysis were used to investigate the relationship between TTE and MRI data. RESULTS: In 16 patients (48.5%), evaluation of NPOTS anatomy was not obtained by TTE, while it was always possible by 4D flow. Peak flow velocity (PV) measurements in Doppler and 4D flow were highly correlated (r = 0.78; P < 0.001). PV >350 cm.s-1 was detected in only one patient (3%) by TTE vs. five patients (15%) by 4D flow. Moreover, a high correlation was found between PV and the right ventricle (RV) mass index to body surface area when using 4D flow (r = 0.63; P < 0.001). The location of NPOTS was determined in all patients using 4D flow and concerned the main pulmonary artery in 42%. DATA CONCLUSION: Compared to TTE, 4D flow MRI provides better sensitivity to detect and locate NPOTS in patients with TGA treated by ASO. 4D flow PV measurements in NPOTS were well correlated with TTE PV and RV mass. LEVEL OF EVIDENCE: 1 Technical Efficacy: Stage 2 J. Magn. Reson. Imaging 2020;51:1699-1705.

Emerging clinical applications of computed tomography.

X-ray computed tomography (CT) has recently been experiencing remarkable growth as a result of technological advances and new clinical applications. This paper reviews the essential physics of X-ray CT and its major components. Also reviewed are recent promising applications of CT, ie, CT-guided procedures, CT-based thermometry, photon-counting technology, hybrid PET-CT, use of ultrafast-high pitch scanners, and potential use of dual-energy CT for material differentiations. These promising solutions and a better knowledge of their potentialities should allow CT to be used in a safe and effective manner in several clinical applications.

Magnetic resonance comparison of left-right heart volumetric and functional parameters in thalassemia major and thalassemia intermedia patients.

OBJECTIVES: To evaluate a population of asymptomatic thalassemia major (TM) and thalassemia intermedia (TI) patients using cardiovascular magnetic resonance (CMR). We supposed that TI group could be differentiated from the TM group based on T2(∗) and that the TI group could demonstrate higher cardiac output. METHODS: A retrospective analysis of 242 patients with TM and TI was performed (132 males, 110 females; mean age 39.6 ± 8 years; 186 TM, 56 TI). Iron load was assessed by T2(∗) measurements; volumetric functions were analyzed using steady-state-free precession sequences. RESULTS: Significant difference in left-right heart performance was observed between TM with iron overload and TI patients and between TM with iron overload and TM without iron overload (P < 0.05); no significant differences were observed between TM without iron overload and TI patients. A significant correlation was observed between T2(∗) and ejection fraction of right ventricle- (RV-) ejection fraction of left ventricle (LV); an inverse correlation was present among T2(∗) values and end-diastolic volume of LV, end-systolic volume of LV, stroke volume of LV, end-diastolic volume of RV, end-systolic volume of RV, and stroke volume of RV. CONCLUSIONS: CMR is a leading approach for cardiac risk evaluation of TM and TI patients.

Dark blood versus bright blood T2 acquisition in cardiovascular magnetic resonance (CMR) for thalassaemia major (TM) patients: evaluation of feasibility, reproducibility and image quality.

OBJECTIVES: To compare the effectiveness of dark blood (DB) versus bright blood (BB) sequences. To assess the intra and inter-observer variability and inter-study reproducibility between BB versus DB. To evaluate image quality level in the two sequences. METHODS: In a setting of 138 patients we performed CMR using cardiac gated Gradient-multiecho single breath-hold BB and DB sequences in the middle ventricular septum. Each acquisition was repeated during the same exam. Truncation method was used to account for background noise. Image quality (IQ) was assessed using a 5 point grading scale and image analysis was conducted by 2 experienced observers. RESULTS: Compared with the conventional BB acquisition, the coefficient of correlation and significance of the DB technique was superior for intra-observer reproducibility (p<0.001), inter-observer reproducibility (p<0.001) and inter-study reproducibility (p<0.001). The variability is also lower for DB sequences for T2* values <14 ms. Assessment of artifacts showed a superior score for DB versus BB scans (4 versus 3, p<0.001). CONCLUSIONS: Improvement in terms of inter observer and inter study variability using DB sequences was obtained. The greatest disparity between them was seen in inter-study reproducibility and higher IQ in DB was seen. Study demonstrates better performance of DB imaging compared to BB in presence of comparable effectiveness.

Relationship among diffusion tensor imaging, EEG activity, and cognitive status in mild cognitive impairment and Alzheimer's disease patients.

Magnetic resonance (MR) diffusion tensor imaging (DTI) can detect microstructural alterations by means of fractional anisotropy (FA) in patients with dementia, also in relation to cognitive status. The present study aimed at investigating the possible relation among white matter damage in DTI, quantitative electroencephalography (EEG) spectral power, and cognitive status in Alzheimer's disease (AD) and mild cognitive impairment (MCI) patients. Forty-seven subjects (8 moderate AD, 18 mild AD, 12 MCI, and 9 healthy controls) underwent brain MR, neuropsychological evaluation, and resting EEG recording. A progressive increase of EEG delta and theta spectral power was observed from controls to patients, mainly in more anterior areas, with a parallel widespread decrease of beta power. Moreover, a progressive decrease of FA from controls to patients in frontal areas and in the corpus callosum (genu) was observed. Correlation analyses indicated convergence among EEG rhythms changes, DTI values, and cognitive status mainly over anterior areas. The decrease of FA values and EEG spectral power changes might represent markers of neurodegenerative dysfunction, possibly preceding macrostructural atrophy.

Relationship between myocardial T2 values and cardiac volumetric and functional parameters in ß-thalassemia patients evaluated by cardiac magnetic resonance in association with serum ferritin levels.

PURPOSE: Myocardial T2 cardiovascular magnetic resonance provides a rapid and reproducible assessment of cardiac iron load in thalassemia patients. Although cardiac involvement is mainly characterized by left ventricular dysfunction caused by iron overload, little is known about right ventricular function. The aim of this study was to assess the relationship between T2 value in myocardium and left-right ventricular volumetric and functional parameters and to evaluate the existing associations between left-right ventricles volumetric and functional parameter, myocardial T2 values and blood ferritin levels. MATERIALS AND METHODS: A retrospective analysis of 208 patients with ß-thalassemia major and thalassemia intermedia was performed (109 males and 99 females; mean age 37.7 ± 13 years; 143 thalassemia major, 65 thalassemia intermedia). Myocardial iron load was assessed by T2 measurements, and volumetric functions were analyzed using the steady state free precession sequence. RESULTS: A significant correlation was observed between EFLV and T2 (p=0.0001), EFRV and T2 (p=0.0279). An inverse correlation was present between DVLV and T2 (p=0.0468), SVLV and T2 (p=0.0003), SVRV and T2 (p=0.0001). There was no significant correlation between cardiac T2 and LV-RV mass indices. A significant correlation was observed between T2 and serum ferritin levels (p<0.001) and between EFLV and serum ferritin (p<0.05). CONCLUSION: Myocardial iron load assessed by T2 cardiac magnetic resonance is associated with deterioration in left-right ventricular function; this is more evident when T2 values fall below 14 ms. CMR appears to be a promising approach for cardiac risk evaluation in TM patients.