The use of cardiac computed tomography angiography in the assessment of percutaneous left atrial appendage closure - Review and experts recommendations endorsed by the Société française d'imagerie cardiaque et vasculaire diagnostique et interventionnelle.

Atrial fibrillation is the most common cause of arrhythmia which is responsible for over 15% of ischemic strokes, most of these being secondary to migration of a left atrial appendage (LAA) thrombus. In patient with contraindication to anticoagulant therapy, percutaneous closure system placement may be indicated. Cardiac computed tomography (CT) angiography plays a central role in the initial assessment as well as in the follow-up. The purpose of the pre-implantation cardiac CT angiography is to evaluate the anatomy of the LAA in order to select the most suitable prosthesis and check for any contraindication to device implantation. Image analysis is divided into four steps that include analysis of the approach; search for a thrombus in the LAA; investigation of the anatomy of the LAA (morphology of the LAA, dimensions of the LAA and choice of device) and cardiac and thoracic assessments. Follow-up involves CT examination to check for correct placement of the device and to detect any complications. On the basis of the results of currently available published research, a panel of experts has issued recommendations regarding cardiac CT angiography prior to percutaneous LAA closure device placement, which were further endorsed by the Société française d'imagerie cardiaque et vasculaire diagnostique et interventionnelle (SFICV).

Magnetic Resonance Imaging Assessment of Kidney Oxygenation and Perfusion During Sickle Cell Vaso-occlusive Crises.

BACKGROUND: Our understanding of the pathophysiologic processes underlying sickle cell nephropathy remains incomplete. We performed a pilot study to investigate the potential value of magnetic resonance imaging (MRI) for the assessment of kidney oxygenation and detection of potential changes to tissue perfusion and cellular integrity during a vaso-occlusive crisis. STUDY DESIGN: A case-control study. SETTING & PARTICIPANTS: 10 homozygous patients with sickle cell disease (SCD), without kidney disease (based on estimated glomerular filtration rate and albuminuria), underwent renal MRI during a vaso-occlusive crisis episode. The imaging data obtained were compared with those for a second MRI performed at steady state (median, 56 [IQR, 37-72] days after the vaso-occlusive crisis MRI). The control group consisted of 10 apparently healthy individuals. MEASUREMENTS: Deoxyhemoglobin level assessed by R2* value was calculated using the blood oxygen level-dependent technique. The intravoxel incoherent motion diffusion-weighted imaging technique was used to calculate D, D*, and F parameters. RESULTS: Median medullary R2* values on steady-state MRI were significantly higher for patients with SCD than for controls (P=0.01) and did not change significantly during the vaso-occlusive crisis. No significant differences in median cortical R2* values were observed. Both cellular integrity (D) and local perfusion (D* and F) were significantly altered in medullary and cortical areas during vaso-occlusive crises in comparison to steady state in patients with SCD. These parameters did not differ significantly between patients with SCD assessed at steady state and the control group. LIMITATIONS: Small sample size, estimation of glomerular filtration rate according to CKD-EPI creatinine equation without adjustment for race. CONCLUSIONS: Deoxyhemoglobin levels in the medullary area are higher in patients with SCD, during vaso-occlusive crises and at steady state, than in controls. Alterations to the tissue perfusion and cellular integrity of renal parenchyma are a common finding during vaso-occlusive crises that provide additional evidence that a vaso-occlusive crisis may be associated with subclinical kidney injury detectable on MRI.

Is multidetector computed tomography a suitable alternative to MR imaging for the assessment of myocardial necrosis after alcohol septal ablation?

BACKGROUND: To compare magnetic resonance (MR) imaging and multidetector computed tomography (MDCT) for the assessment of myocardial infarction (MI) after alcohol septal ablation (ASA). METHODS: Ten patients (mean age, 60 years ± 16) were examined with both MDCT and 1.5-T MR imaging performed 10 minutes after injection, within 3 days after ASA. Half of them had a temporary pacemaker (PM) during MDCT examination. Global image quality (IQ) and localization of MI were noticed on both MDCT and MR images. Volumes of MI, contrast-to-noise ratios (CNR) and signal-to-noise ratios (SNR) were also calculated. ASA effectiveness was evaluated by echocardiography immediately and 3 months after procedure. RESULTS: Global IQ was considered adequate for both procedures. In 8 patients, MI reached the basal part of the septum on both MDCT and MR images. The 2 remaining patients exhibited sparing of the basal septum on MDCT and MR images. Volumes of MI were within the same range with the 2 techniques (MDCT: 22.1 ± 8.8 mL; MR imaging: 23.8 ± 9.4 mL) and correlated well each other (R(2)=0.85, p<0.002). The 2 patients with sparing of the basal interventricular septum had persistent gradient on echocardiography 3 months after ASA, suggesting failure of the procedure. The volumes of MI didn't correlate with the reduction of pressure gradient on echocardiography 3 months after ASA (R(2)=0.02, p<0.05). CONCLUSIONS: Evaluation of post ASA MI is feasible with MDCT by comparison with MR imaging. MDCT might serve as an alternative imaging method in case of PM implantation.

Multiple myeloma treatment response assessment with whole-body dynamic contrast-enhanced MR imaging.

PURPOSE: To compare posttreatment bone marrow changes at whole-body dynamic contrast material-enhanced magnetic resonance (MR) imaging with clinical response in patients with multiple myeloma (MM) and to determine if this technique can be used to assess treatment response in patients with MM. MATERIALS AND METHODS: This study was approved by an institutional review board; all patients gave informed written consent. Thirty patients (21 men, nine women; mean age, 58 years +/- 10 [standard deviation]) underwent whole-body dynamic contrast-enhanced MR imaging before treatment, after induction chemotherapy (n = 30), and after autologous stem cell transplantation (ASCT) (n = 20). Maximal percentages of bone marrow (BME(max)) and focal lesion (FLE(max)) enhancement were assessed at each MR imaging examination. Clinical responses were determined on the basis of international uniform response criteria. Posttreatment changes in BME(max)and FLE(max)were compared with clinical response to therapy by using the Mann-Whitney U test. Receiver operating characteristic (ROC) analysis of posttreatment BME(max)was used to identify poor responders. RESULTS: Eleven of 30 patients were good responders to induction chemotherapy; 16 of 20 patients were good responders to ASCT. After induction chemotherapy, mean BME(max)differed between good and poor responders (94.3% vs 138.4%, respectively; P = .02). With the exclusion of results from six examinations with focal lesions in which a poor clinical response was classified but BME(max)had normalized, a posttreatment BME(max)of more than 96.8% had 100% sensitivity for the identification of poor responders (specificity, 76.9%; area under the ROC curve, 0.90; P = .0001). Mean FLE(max)after induction chemotherapy did not differ between good and poor responders. Mean timing (ie, the number of postcontrast dynamic acquisitions where FLE(max)was observed) was significantly delayed in good responders compared with poor responders (4.7 vs 2.9, P < .0001). Post-ASCT MR imaging results correctly depicted all four clinically good responders whose disease subsequently progressed. CONCLUSION: With quantitative analysis of BME(max)and the timing of FLE(max), whole-body dynamic contrast-enhanced MR imaging can be used to assess treatment response in patients with MM.