[SARS-COV-2 myocarditis. An update]. / Myocardite et maladie à COVID-19 : où en est-on ?

The outbreak of the SARS-CoV-2 virus responsible for the COVID-19 disease has given rise to a new disease whose boundaries are still to be discovered. While the first data suggested a purely respiratory infection, the most recent publications highlight a large pleomorphism of the disease, responsible for multiple organ damage, of which cardiac injury seems to be the most represented. This cardiac injury can present as acute myocarditis. Our aim was to discuss the pathophysiological rationale underlying the existence of SARS-CoV-2 myocarditis and to analyze the literature data regarding the diagnosis and treatment of this particular entity.

Usefulness of T2 ratio in the diagnosis and prognosis of cardiac amyloidosis using cardiac MR imaging.

PURPOSE: To detect if a difference of T2 ratio, defined as the signal intensity (SI) of the myocardium divided by the SI of the skeletal muscle on T2-weigthed cardiac magnetic resonance (CMR) imaging, exists between patients with systemic amyloidosis, by comparison to control subjects. To determine if a relationship exists between T2 ratio and the overall mortality. MATERIALS AND METHODS: CMR imaging examinations of 73 consecutive patients (48 men, 25 women; mean age, 63 years±15[SD]) with amyloidosis and suspicion of CA and 27 control subjects were retrospectively analyzed after institutional review board approval. Final diagnosis of CA was retained in case of histological confirmation of CA, typical pattern of CA on imaging and/or positivity of 99Technetium-hydroxymethylene diphosphonate scintigraphy. Patients were divided in 2 groups according to the presence or the absence of CA. T2 ratios were calculated in patients with and those without CA and in control subjects with using analysis of variance. Prognostic value of T2 ratio was studied with a Kaplan-Meier curve. RESULTS: Thirty-five patients (51%) had CA and 33 (49%) were free from CA. T2 ratio was lower in patients with CA (1.18±0.29) than in patients without cardiac involvement (1.37±0.35) (P=0.03) and control subjects (1.45±0.24) (P=0.004). A T2 ratio of 1.36 was the best threshold value for predicting CA with a sensitivity of 63% and a specificity of 73%. Kaplan-Meier analysis showed a significant relationship between a shortened overall survival and a T2 ratio<1.36. CONCLUSION: Patients with CA exhibit lower T2 ratio on CMR imaging by comparison with patients free of CA and control subjects.

Post-procedure bleeding in interventional radiology.

Following interventional radiology procedures, bleeding can occur in 0.5 to 4% of the cases. Risk factors are related to the patient, to the procedure, and to the end organ. Bleeding is treated usually by interventional radiologists and consists mainly of embolization. Bleeding complications are preventable: before the procedure by checking hemostasis, during the procedure by ensuring the accurate puncture site (with ultrasound or fluoroscopy guidance) or by treating the puncture path using gelatin sponge, curaspon(®), biological glue or thermocoagulation, and after the procedure by carefully monitoring the patients.

Ruptured visceral artery aneurysms.

Visceral artery aneurysms are rare but their estimated mortality due to rupture ranges between 25 and 70%. Treatment of visceral artery aneurysm rupture is usually managed by interventional radiology. Specific embolization techniques depend on the location, affected organ, locoregional arterial anatomy, and interventional radiologist skill. The success rate following treatment by interventional radiology is greater than 90%. The main complication is recanalization of the aneurysm, showing the importance of post-therapeutic monitoring, which should preferably be performed using MR imaging.

Is it possible to do without the study of myocardial perfusion in 2013?

The analysis of myocardial perfusion is a key step in the cardiac MRI examination. In routine work, this exploration carried out at rest is based on the qualitative first pass study of gadolinium with an ECG-triggered saturation recovery bFFE sequence. In view of recent knowledge, the analysis of the myocardial perfusion under vasodilator stress may be carried out by scintigraphy or MRI, the latter benefiting from the absence of exposure to ionizing rays and a lower cost. Besides coronary disease, the perfusion sequence provides a rich semiology to compare with the clinics and the data from other sequences. Arterial Spin Labeling (ASL) is an alternative technique used in the animal to quantify myocardial perfusion.

Estimation of tissue contractility from cardiac cine-MRI using a biomechanical heart model.

The objective of this paper is to propose and assess an estimation procedure-based on data assimilation principles-well suited to obtain some regional values of key biophysical parameters in a beating heart model, using actual Cine-MR images. The motivation is twofold: (1) to provide an automatic tool for personalizing the characteristics of a cardiac model in order to achieve predictivity in patient-specific modeling and (2) to obtain some useful information for diagnosis purposes in the estimated quantities themselves. In order to assess the global methodology, we specifically devised an animal experiment in which a controlled infarct was produced and data acquired before and after infarction, with an estimation of regional tissue contractility-a key parameter directly affected by the pathology-performed for every measured stage. After performing a preliminary assessment of our proposed methodology using synthetic data, we then demonstrate a full-scale application by first estimating contractility values associated with 6 regions based on the AHA subdivision, before running a more detailed estimation using the actual AHA segments. The estimation results are assessed by comparison with the medical knowledge of the specific infarct, and with late enhancement MR images. We discuss their accuracy at the various subdivision levels, in the light of the inherent modeling limitations and of the intrinsic information contents featured in the data.

[Evaluation of noninvasive diagnostic criteria for hepatocellular carcinoma on pretransplant MRI (2010): correlation between MR imaging features and histological features on liver specimen]. / Évaluation des critères diagnostiques non invasifs du carcinome hépatocellulaire sur IRM pré-greffe hépatique (2010) : corrélations IRM - anatomopathologiques sur explants hépatiques.

PURPOSE: To validate the 2010 diagnostic criteria from the American Association for the Study of Liver Diseases (AASLD) for hepatocellular carcinoma (HCC) on MRI using the surgical liver specimen as a gold standard. PATIENTS AND METHODS: A total of 21 liver transplant recipients were retrospectively included. Each underwent surgery because of HCC between January 2007 and January 2008. Pre-transplant MRI was performed on a 1.5 Tesla MR unit. The T1W and T2W signal and kinetic contrast enhancement were correlated for each lesion with the surgical specimen. Lesion diameters between MRI and specimen were compared (Spearman). A multivariate model was created (R statistics software package) to predict the presence and grade of tumor differentiation (WHO, Edmonson Steiner). RESULTS: A total of 71 nodules were detected at histology, including 54 HCC (mean size: 25.3mm) compared to 68 on MRI. There was moderate agreement (r=0.58, P<0.001) between the maximum lesion diameters measured on MRI and at histology. Wash-out on MRI provided an accuracy of 75 % for the detection of HCC (sensitivity=75 %, specificity=76 %). Adding T2W hyperintensity to the AASLD criteria increased the sensitivity of MRI from 70.3 % to 77.7 % for the diagnosis of HCC and from 67.6 % to 79 % for nodules less than 20mm in diameter, without affecting specificity. On multivariate analysis, wash out as a single variable was significantly associated with a diagnosis of HCC (P<0.01, odds ratio 12.0, CI 95 % [2.6-55.5]). T1W hyperintensity (P=0.04, odds ratio 5.4) and loss of signal on opposed-phase images (P=0.02, odds ratio 9.2) were predictive of good differentiation. CONCLUSION: On MRI, the AASLD criteria or presence of wash out within a liver nodule in patients with underlying chronic hepatocellular disease are suggestive of tumoral transformation. The addition of T2W hyperintensity to the AASLD criteria increases the detection of HCC, especially nodules smaller than 20mm.

[Cardiac MRI: technical considerations]. / Les conditions techniques d'utilisation de l'IRM cardiaque.

Establishing a clinical cardiovascular magnetic resonance imaging (MRI) program needs a dedicated technical surroundings as well as a specific and expert staff. These guidelines based either on proofs or on expert consensus are stated in order to help the physicians to reach or maintain the competence required for clinical use of cardiovascular MRI. After the general safety statements, the guidelines are focused on hardware and software requirements, the MRI sequences and views, the post-acquisition analysis, and the staff. Specific safety concerns are then approached, more particularly stress testing MRI.

Assessment of calf muscle contraction by diffusion tensor imaging.

The goal of this study was to assess the changes of water diffusion during contraction and elongation of calf muscles using diffusion tensor (DT) MRI in normal volunteers. Twenty volunteers (mean age, 29+/-4 years) underwent DT MRI examination of the right calf. Echo planar imaging sequence was performed at rest, during dorsal flexion and during plantar flexion. The three eigenvalues (lambda1, lambda2, and lambda3), apparent diffusion coefficient (ADC) and fractional anisotropy (FA) of the diffusion tensor were calculated for medial gastrocnemius (mGM) and tibialis anterior (TA). A fiber tractography was performed on both muscles. Non-parametric Wilcoxon and Mann Whitney tests were used for statistical evaluation. At rest, lambda1, lambda2 and ADC of mGM were higher than their counterparts of TA (P<0.01). During dorsal flexion, the three eigenvalues and ADC of TA significantly increased (P<0.05) as their counterparts of mGM slightly decreased (P=NS). Opposite variations were detected during plantar flexion of the foot. Visual analysis evidenced a relationship between 3D representations of MRI fibers and physiological state of muscles. Contraction of calf muscles produces changes in DT parameters, which are related to the physiological state of the muscle.

[Persistent sciatic artery: possible false negative imaging]. / Artère sciatique persistante: possibles faux-négatifs de l'imagerie.

Persistent sciatic artery is a rare congenital malformation due to the lack of regression of the dorsal arterial axis of the embryo that can be revealed by serious complications. We report a case of bilateral persistent sciatic artery revealed by subacute distal ischemia. This case illustrates the possibility of false negative imaging and the importance of ruling out this diagnosis in case of recurrent and apparently idiopathic distal embolism.

[Evaluation of left ventricular function: echocardiography, MRI or CT?]. / Evaluation de la fonction ventriculaire gauche: échocardiographie, IRM ou scanner?

The objective of this article is to clarify the advantages and limits of echocardiography, MRI, and CT for the determination of left ventricular (LV) function, emphasising the importance of evaluating global ventricular function. MRI is the reference technique, owing to its precision, reproducibility, and innocuous nature. However, echography is performed much more frequently because it is more widely available and easier to carry out. It is our reference technique in everyday practice. More recently, synchronised multi-slice tomodensitometry has provided dynamic reconstructed images of the left ventricle throughout the cardiac cycle, offering a succession of short axis views covering the entire volume of the ventricle. These acquisitions, in addition to non-invasive coronary angiography, allow the LV ejection fraction to be determined. With MRI, study of the LV function does not require any contrast medium to be injected and makes use of effective semi-automatic segmentation programs.

[Endovascular stent grafting for chronic proximal thoracic aortic pseudoaneurysm]. / Faux anévrysme chronique de l'aorte thoracique descendante proximale: traitement endovasculaire percutané.

Chronic descending aortic pseudoaneurysm generally result from traumatic and can spontaneously progress to rupture. We report the case of a 70-year-old patient presenting a chronic pseudoaneurysm of the thoracic aorta treated by endovascular stent-grafting. The patient underwent imaging evaluation for endoluminal repair: thoracic aorta was evaluated by contrast-enhanced CT scan and supra-aortic and iliac vessels were evaluated by MRI-imaging. Stent-graft was deployed under fluoroscopic guidance across the aneurysmal defect. The left sub-clavian artery was covered, but no ischemic symptoms appeared and transposition of the left sub-clavian artery was not necessary. Clinical and radiological follow-up at 6 and 30 months showed total exclusion and thrombosis of the pseudoaneurysm. Chronic pseudoaneurysm of the thoracic aorta do benefit from endoluminal repair, which is adapted to patients with high surgical risk.

[Imaging of salivary lithiasis]. / Imagerie des lithiases salivaires.

Lithiasis is the most common disease of salivary glands after mumps. The purpose of this review is to analyze the respective role of the different available imaging techniques for the diagnosis of lithiasis and related complications since the treatment of salivary lithiasis has evolved with the emergence of minimally invasive and non surgical techniques. In spite of its limitations, US represents an excellent first line imaging technique because it is non-invasive and widely available. Non contrast helical CT with multiplanar reconstructions seems to be the gold standard for the diagnosis of lithiasis, especially when small and poorly calcified since these may not be visible on standard radiographs. CT allows accurate characterization of the number and position of lithiasis. MR Sialography is increasingly replacing the more invasive conventional sialography for the non invasive visualization of the ductal system of major salivary glands even though conventional sialography has a higher spatial resolution.

[Noninvasive coronary artery imaging: CT and MR]. / Imagerie non invasive des artères coronaires: TDM et IRM.

The advent of helical multidetector CT has significantly modified several traditional clinical approaches to cardiovascular diagnosis. The current availability of rapid image acquisition has provided the basis for investigating direct imaging in real time of cardiac structures using CT. Application of thin-section submillimetric image acquisitions to three-dimensional (3D) reconstruction algorithms produces 3D data sets from which images of the coronary arteries may be obtained in any anatomic plane. The advantage of the submillimetric isotropic spatial resolution is partly offset by reduced temporal resolution as well as reduced contrast resolution compared to MRI. This lack in contrast sensitivity prevents accurate perfusion imaging and restricts the clinical use to coronary artery imaging. Moreover, the large amount of iodinated contrast medium injected has potential nephrotoxic effects, which can be deleterious if coronary artery angiography must to be performed. On the other hand, MRI has less spatial resolution, and acquisitions must be performed in the plane of each coronary artery because of reduced volume coverage. Both techniques play a role in the non-invasive assessment of coronary artery disease, by providing complementary information already useful in a growing number of clinical situations.

Proliferative myositis in a patient with AIDS.

We report a case of proliferative myositis in the right biceps of a 56-year-old man with acquired immune deficiency syndrome (AIDS). Imaging methods included sonography, computed tomography and magnetic resonance imaging. The diagnosis was made by a core-cut biopsy and fine needle aspiration biopsy with immunohistochemical analysis. The lesion disappeared after 2 months without treatment. It is particularly important to determine whether intramuscular masses arising in patients with AIDS are due to an infectious or malignant process.

[Complications of myocardial infarction]. / Complications de l'infarctus du myocarde.

Most acute complications of myocardial infarction do not need emergency imaging, since they often result in death prior to hospital admission: ventricular fibrillation and tachycardia, papillary muscle or septal rupture, fissuration and tamponade. Imaging can play a role at distance of the acute phase (papillary muscle dysfunction, false aneurysm, development of a mural thrombus associated to left ventricular apical dyskinesis, with potential embolic complications).