Safety and efficacy of reperfusion therapies in acute ischemic stroke related to left ventricular thrombus: A retrospective cohort study.

BACKGROUND: Left ventricular thrombus (LVT) is a source of cardiogenic embolic stroke. Conflicting data exist in the literature regarding the utilization of intravenous thrombolysis (IVT) at the acute phase of stroke in presence of LVT. We sought to assess the efficacy and safety of reperfusion therapies (IVT and/or thrombectomy) in patients with LVT. METHODS: We retrospectively analyzed patients with acute ischemic stroke and proven LVT and divided them in two groups: an intervention group with patients treated by reperfusion therapies and a control group with untreated patients. RESULTS: Between 2009 and 2021, 3890 patients were treated by reperfusion therapies in the Lyon stroke center, 33 of whom (0.9%) had LVT. We identified 27 control patients. There were more embolic recurrences at six months in the intervention group than in the control group (nine recurrences versus three, P=0.03, OR=13.56, 95% CI [1.5;195]). Only two early embolic recurrences (< 24h) occurred, both in the IVT group. There was a 4.8-fold decrease in the median NIHSS score between baseline and 24h follow-up in the intervention group (P<0.0001), and the two groups exhibited similar six-month mortality. At stroke onset, cardiopathy was known in 70% of patients, while LVT was known in 30%. CONCLUSION: Acute reperfusion therapies seem to be effective in the context of stroke in patients with LVT. However, further studies are needed to support the hypothesis that stroke recurrence might be related to the use of IVT.

Early Detection of Underlying Cavernomas in Patients with Spontaneous Acute Intracerebral Hematomas.

BACKGROUND AND PURPOSE: Early identification of the etiology of spontaneous acute intracerebral hemorrhage is essential for appropriate management. This study aimed to develop an imaging model to identify cavernoma-related hematomas. MATERIALS AND METHODS: Patients 1-55 years of age with acute (≤7 days) spontaneous intracerebral hemorrhage were included. Two neuroradiologists reviewed CT and MR imaging data and assessed the characteristics of hematomas, including their shape (spherical/ovoid or not), their regular or irregular margins, and associated abnormalities including extralesional hemorrhage and peripheral rim enhancement. Imaging findings were correlated with etiology. The study population was randomly split to provide a training sample (50%) and a validation sample (50%). From the training sample, univariate and multivariate logistic regression was performed to identify factors predictive of cavernomas, and a decision tree was built. Its performance was assessed using the validation sample. RESULTS: Four hundred seventy-eight patients were included, of whom 85 had hemorrhagic cavernomas. In multivariate analysis, cavernoma-related hematomas were associated with spherical/ovoid shape (P < .001), regular margins (P = .009), absence of extralesional hemorrhage (P = .01), and absence of peripheral rim enhancement (P = .002). These criteria were included in the decision tree model. The validation sample (n = 239) had the following performance: diagnostic accuracy of 96.1% (95% CI, 92.2%-98.4%), sensitivity of 97.95% (95% CI, 95.8%-98.9%), specificity of 89.5% (95% CI, 75.2%-97.0%), positive predictive value of 97.7% (95% CI, 94.3%-99.1%), and negative predictive value of 94.4% (95% CI, 81.0%-98.5%). CONCLUSIONS: An imaging model including ovoid/spherical shape, regular margins, absence of extralesional hemorrhage, and absence of peripheral rim enhancement accurately identifies cavernoma-related acute spontaneous cerebral hematomas in young patients.

FLAIR Vascular Hyperintensities as a Surrogate of Collaterals in Acute Stroke: DWI Matters.

BACKGROUND AND PURPOSE: FLAIR vascular hyperintensities are thought to represent leptomeningeal collaterals in acute ischemic stroke. However, whether all-FLAIR vascular hyperintensities or FLAIR vascular hyperintensities-DWI mismatch, ie, FLAIR vascular hyperintensities beyond the DWI lesion, best reflects collaterals remains debated. We aimed to compare the value of FLAIR vascular hyperintensities-DWI mismatch versus all-FLAIR vascular hyperintensities for collateral assessment using PWI-derived collateral flow maps as a reference. MATERIALS AND METHODS: We retrospectively reviewed the registries of 6 large stroke centers and included all patients with acute stroke with anterior circulation large-vessel occlusion who underwent MR imaging with PWI before thrombectomy. Collateral status was graded from 1 to 4 on PWI-derived collateral flow maps and dichotomized into good (grades 3-4) and poor (grades 1-2). The extent of all-FLAIR vascular hyperintensities and FLAIR vascular hyperintensities-DWI mismatch was assessed on the 7 cortical ASPECTS regions, ranging from 0 (absence) to 7 (extensive), and associations with good collaterals were compared using receiver operating characteristic curves. RESULTS: Of the 209 included patients, 133 (64%) and 76 (36%) had good and poor collaterals, respectively. All-FLAIR vascular hyperintensity extent was similar between collateral groups (P = .76). Conversely, FLAIR vascular hyperintensities-DWI mismatch extent was significantly higher in patients with good compared with poor collaterals (P < .001). The area under the curve was 0.80 (95% CI, 0.74-0.87) for FLAIR vascular hyperintensities-DWI mismatch and 0.52 (95% CI, 0.44-0.60) for all-FLAIR vascular hyperintensities (P < .001 for the comparison), to predict good collaterals. Variables independently associated with good collaterals were smaller DWI lesion volume (P < .001) and larger FLAIR vascular hyperintensities-DWI mismatch (P = .02). CONCLUSIONS: In acute ischemic stroke with large-vessel occlusion, the extent of FLAIR vascular hyperintensities does not reliably reflect collateral status unless one accounts for DWI.

Comparison of magnetic resonance angiography techniques to brain digital subtraction arteriography in the setting of mechanical thrombectomy: A non-inferiority study.

INTRODUCTION: We performed a non-inferiority study comparing magnetic resonance angiography (MRA) techniques including contrast-enhanced (CE) and time-of-flight (TOF) with brain digital subtraction arteriography (DSA) in localizing occlusion sites in acute ischemic stroke (AIS) with a prespecified inferiority margin taking into account thrombus migration. MATERIALS AND METHODS: HIBISCUS-STROKE (CoHort of Patients to Identify Biological and Imaging markerS of CardiovascUlar Outcomes in Stroke) includes large-vessel-occlusion (LVO) AIS treated with mechanical thrombectomy (MT) following brain magnetic resonance imaging (MRI) including both CE-MRA and TOF-MRA. Locations of arterial occlusions were assessed independently for both MRA techniques and compared to brain DSA findings. Number of patients needed was 48 patients to exclude a difference of more than 20%. Discrepancy factors were assessed using univariate general linear models analysis. RESULTS: The study included 151 patients with a mean age of 67.6±15.9years. In all included patients, TOF-MRA and CE-MRA detected arterial occlusions, which were confirmed by brain DSA. For CE-MRA, 38 (25.17%) patients had discordant findings compared with brain DSA and 50 patients (33.11%) with TOF-MRA. The discordance factors were identical for both MRA techniques namely, tandem occlusions (OR=1.29, P=0.004 for CE-MRA and OR=1.61, P<0.001 for TOF-MRA), proximal internal carotid artery occlusions (OR=1.30, P=0.002 for CE-MRA and OR=1.47, P<0.001 for TOF-MRA) and time from MRI to MT (OR=1.01, P=0.01 for CE-MRA and OR=1.01, P=0.02 for TOF-MRA). CONCLUSION: Both MRA techniques are inferior to brain DSA in localizing arterial occlusions in LVO-AIS patients despite addressing the migratory nature of the thrombus.

Multifocal arterial wall contrast - enhancement in ischemic stroke: A mirror of systemic inflammatory response in acute stroke.

PURPOSE: Intracranial plaque gadolinium enhancement revealed by high-resolution MRI imaging (HR MRI) is considered as a marker of plaque inflammation, a contributing factor of plaque unstability. The aim of the present study was to assess the distribution of gadolinium enhancement in intracranial atherosclerosis. METHODS: Single center analysis of ischemic stroke patients with intracranial atherosclerotic stenosis of M1 or M2 segments of middle cerebral artery, or terminal internal carotid artery (ICA) based on CT-angio or MR-angio. High-resolution MRI imaging (HRMRI) was performed within 6 first weeks following the index event, with 3DT2 BB (black-blood) and 3D T1 BB MR sequences pre and post-contrast administration. RESULTS: We identified 8 patients with 14 plaques, 4 were deemed non-culprit and 10 culprit. All culprit plaques (10/10 plaques) and 3 out of 4 non-culprit plaques showed a gadolinium enhancement. CONCLUSION: At the acute/subacute stage of stroke, a gadolinium enhancement may affect multiple asymptomatic intracranial plaques and may reflect a global inflammatory state.

Combined analysis of MGMT methylation and dynamic-susceptibility-contrast MRI for the distinction between early and pseudo-progression in glioblastoma patients.

INTRODUCTION: Currently, no single diagnostic modality allows the distinction between early progression (EP) and pseudo-progression (Psp) in glioblastoma patients. Herein we aimed to identify the characteristics associated with EP and Psp, and to analyze their diagnostic value alone and in combination. MATERIAL AND METHODS: We reviewed the clinical, conventional magnetic resonance imaging (MRI), and molecular characteristics (MGMT promoter methylation, IDH mutation, and EGFR amplification) of glioblastoma patients who presented an EP (n=59) or a Psp (n=24) within six months after temozolomide radiochemotherapy. We analyzed relative cerebral blood volume (rCBV) and relative vessel permeability on K2 maps (rK2) in a subset of 33 patients using dynamic-susceptibility-contrast MRI. RESULTS: In univariate analysis, EP was associated with neurological deterioration, higher doses of dexamethasone, appearance of a new enhanced lesion, subependymal enhancement, higher rCBV and rK2 values. Psp occurred earlier after radiotherapy completion and was associated with IDH1 R132H mutation, and MGMT methylation. In multivariate analysis, rCBV, rK2, and MGMT methylation status were independently associated with EP and Psp. All patients with a methylated MGMT promoter and a low rCBV (<1.75) were classified as Psp while all patients with an unmethylated MGMT promoter and a high rCBV (≥1.75) were classified as EP. Among patients with discordant MGMT methylation and rCBV characteristics, higher rK2 values tended to be associated with EP. CONCLUSION: Combined analysis of MGMT methylation, rCBV and vessel permeability on K2 maps seems helpful to distinguish EP from Psp. A prospective study is warranted to confirm these results.

Imagery of pineal tumors.

Pineal tumors are rare and include a large variety of entities. Germ cell tumors are relatively frequent and often secreting lesions. Pineal parenchymal tumors include pineocytomas, pineal parenchymal tumor of intermediate differentiation, pineoblastomas and papillary tumors of the pineal region. Other lesions including astrocytomas and meningiomas as well as congenital malformations i.e. benign cysts, lipomas, epidermoid and dermoid cysts, which can also arise from the pineal region. Imagery is often non-specific but detailed analysis of the images compared with the hormone profile can narrow the spectrum of possible diagnosis.

Evaluation of image quality of DWIBS versus DWI sequences in thoracic MRI at 3T.

PURPOSE: To compare diffusion weighted imaging with background suppression (DWIBS) sequence with classic spectral diffusion sequence (DWI) with and without respiratory gating in mediastinal lymph node analysis at 3T. MATERIALS AND METHODS: 26 patients scheduled for mediastinoscopic lymph node analysis, prospectively undergone a thoracic 3T MRI with DWIBS (FatSat=STIR; TR/TE=6674.1/44.7ms; IR=260 ms) and DWI sequences (FatSat=SPIR; TR/TE=1291/59.6 ms) (b=0-400-800 s/mm2) with and without (free breathing) respiratory gating. Images at b=800 were analyzed by two radiologists. They performed qualitative analysis of fat-sat homogeneity and motion artifacts, rated from 0 to 4, and quantitative evaluation by studying signal to background (STB) of lymph nodes. RESULTS: Quality of fat suppression was significantly higher for DWIBS than for DWI both for free-breathing (score 3.48±0.65 vs. 1.76±0.96, p<0.0001) and respiratory-gated scans (3.17±0.77 vs. 1.72±0.73, p=0.0001). Similarly, artifacts were reduced with DWIBS (3.16±0.47 vs. 1.76±0.59, p<0.0001; 3.0±0.73 vs. 2.04±0.53, p=0.0001). Quantitative analysis showed higher STB with DWIBS (3.26±1.83 vs. 0.98±0.44, p<0.0001; 3.56±, 2.09 vs. 0.92±0.59, p<0.0001). Gating did not improve image quality and STB on DWIBS (p>0.05). CONCLUSION: In thoracic MRI, ungated DWIBS sequence improves fat-sat homogeneity, reduces motion artifacts and increases STB of lymph nodes. Respiratory gating does not improve DWIBS image quality.

Grading of small hepatocellular carcinomas (≤2 cm): correlation between histology, T2 and diffusion-weighted imaging.

OBJECTIVE: To evaluate the capacity of diffusion-weighted imaging (DWI) to determine the histological grade of small-sized hepatocellular carcinomas (HCCs) in liver cirrhosis in comparison with T2 weighted imaging. METHODS: 51 cirrhotic patients with 63 histologically proven HCCs ≤2 cm underwent abdominal MRI, including DWI (b-values 50, 400 and 800 s mm(-2)) and T2 weighted sequences. HCCs were classified into well-differentiated HCCs (n = 37) and moderately differentiated HCCs (n = 26). Relative contrast ratios (RCRs) between the lesions and the surrounding liver were performed and compared between the two groups for T2 weighted images, each b-value and apparent diffusion coefficients (ADCs). A receiver operating characteristic (ROC) analysis was performed to compare RCRs in T2 and diffusion-weighted images. RESULTS: We found significant differences in RCRs between well-differentiated vs moderately differentiated HCCs for b = 50, 400 and 800 s mm(-2) and T2 weighted images (1.35 ± 0.36 vs 1.86 ± 0.62; 1.35 ± 0.38 vs 1.82 ± 0.60; 1.27 ± 0.30 vs 1.74 ± 0.53; 1.14 ± 0.18 vs 1.43 ± 0.28, respectively; p < 0.001), whereas no significant differences were observed in ADC and ADC RCR (1.05 ± 0.19 vs 0.99 ± 0.15 and 1.1 ± 0.22 vs 1.09 ± 0.23; p = 0.16 and p = 0.82, respectively). No significant difference was found in the areas under the ROC curve for RCRs of T2 weighted images and every DWI b-value (p = 0.18). CONCLUSION: The RCR measurement performed in DWI 50, 400 and 800 b-values and T2 demonstrated a significant difference between well-differentiated and moderately differentiated small-sized HCCs. Furthermore, no difference was shown by using either ADC or ADC RCR. ADVANCES IN KNOWLEDGE: DWI with RCR measurement may be a valuable tool for non-invasively predicting the histological grade of small HCCs.

Whole-body MRI with diffusion-weighted sequences compared with 18 FDG PET-CT, CT and superficial lymph node ultrasonography in the staging of advanced cutaneous melanoma: a prospective study.

OBJECTIVES: The aim of our study was to compare the diagnostic performances of non-radiating whole-body magnetic resonance imaging (wbMRI), either volumetric, with Volumetric interpolated breath-hold examination (VIBE) or metabolic, with diffusion-weighted sequences (wbMRI), with classical irradiating techniques such as PET-CT, CT and with lymph node ultrasonography (US) for the staging of advanced melanoma. PATIENTS AND METHODS: Thirty-seven melanoma AJCC stage IV patients were prospectively included. All images were independently interpreted without prior knowledge of the results of studies performed with concurrent techniques, and all imaging techniques were scheduled within a mean interval of 7 days. The overall and site-specific diagnosis performances of each imaging modality were studied, as well as the interest of combined MRI VIBE and diffusion sequences. RESULTS: The number of visceral or lymph node metastases spotted was, respectively, 218, with 125 metastases for wbMRI, 191/103 for PET-CT, 209/115 for CT and 33/13 for lymph node US. No statistically significant difference (P < 0.05) of overall diagnostic performances between wbMRI (Se 84%, Sp 87.1%, PPV 89.8%, NPV 80.2%) and PET-CT (Se 79.8%, Sp 93.1%, PPV 93.2%, NPV 79.4%) was observed. No statistically significant difference was found between wbMRI and PET-CT with two channels for CT with respect to different metastatic sites. Compared with the CT, wbMRI had significantly better overall specificity (P = 0.0011) and PPV (P = 0.02). For lung exploration, sensitivity of wbMRI (51.6%) was inferior to CT (71.4%). To detect superficial metastatic lymph nodes, wbMRI and US both showed high diagnostic accuracy with no statistically significant difference. Intra-observer agreement was almost perfect for all imaging modalities considering the overall staging. Inter-observer agreement for wbMRI and diffusion alone was almost perfect except for bone and lymphatic sites. Overall diagnostic performance of diffusion alone was significantly inferior to those of combined VIBE and diffusion sequences. CONCLUSIONS: Whole-body MRI, using diffusion weighted sequences, was a reliable non-radiating imaging for staging of melanoma and offers the same diagnostic performances than combined CT, PET-CT and lymph node US.

Synchrotron radiation X-ray phase micro-computed tomography as a new method to detect iron oxide nanoparticles in the brain.

PURPOSE: The purpose of this study was to introduce synchrotron radiation X-ray phase computed tomography (SR-PCT) as a new method of visualizing ultrasmall superparamagnetic particles of iron oxide (USPIO) distribution into the brains of mice with neuroinflammation. PROCEDURES: The sensitivity of the technique was assessed by performing back-to-back SR-PCT and magnetic resonance imaging (MRI) in mice stereotaxically injected with a range of USPIO concentrations. Eight mice with cerebral ischemia were then intravenously injected with USPIOs and imaged back-to-back with MRI and SR-PCT. RESULTS: SR-PCT proved sensitive enough to detect iron in nanomolar quantities. In stroke-induced animals, SR-PCT showed hyperintense areas in the regions of MR signal loss and immunostaining for macrophages. SR-PCT, moreover, identified brain anatomy as clearly as histology, without the need for sectioning or staining, with an examination time of 44 min per brain at an isotropic spatial resolution of 8 µm. CONCLUSION: SR-PCT has potential for cellular imaging in intact brain, with unequaled neuroanatomy.

Superinfection of focal liver lesions after bile duct procedures.

OBJECTIVES: Pyogenic liver abscess is a rare condition in the general population. The source of infection is most often biliary, and more rarely gastrointestinal via the portal tract, or even hematogenic. Other than in special contexts (scarring after radiofrequency ablation), focal liver lesions are not a usual risk factor for hepatic abscesses in patients with a history of bile duct procedures (sphincterotomy, biliary stenting, biliary enteric anastomosis). MATERIALS AND METHOD - RESULTS: We report four cases of focal liver lesions (two patients with benign lesions of the biliary cyst type and two other patients with lesions due to pancreatic cancer) complicated by a superinfection in patients with a history of bile duct procedures. There were no predisposing factors other than a context of cancer or diabetes. CONCLUSION: Superinfection of a focal liver lesion should be considered when there is a suggestive clinical picture and a change in the appearance of the lesion in patients with a history of bile duct procedures in a context of cancer or diabetes.

[Diagnosis of cardiac amyloidosis using magnetic resonance imaging: a new reliable, non-invasive technique to be validated]. / Diagnostic de l'amylose cardiaque par imagerie par résonnance magnétique nucléaire : une nouvelle méthode fiable, non invasive, en cours de validation.

INTRODUCTION: Amyloidosis is characterised by extracellular tissue deposition of insoluble fibrillar protein in various organs. Cardiac involvement is associated with the worse prognosis and the main cause of death. It needs a prompt diagnosis, which could be sometimes difficult to obtain. Endomyocardial biopsy remains the gold standard diagnostic technique, but recent studies on cardiac magnetic resonance imaging (MRI) indicate that this imaging procedure may be useful to the diagnosis of amyloidosis. CASE REPORTS: We report three patients with systemic amyloidosis who underwent cardiac MRI for the diagnosis or the follow-up of their disease. In addition to poorly specific signs of restrictive cardiomyopathy, cardiac MRI showed, after gadolinium enhancement that was considered characteristic of amyloidosis. CONCLUSION: Cardiac MRI is a useful diagnostic tool in cardiac amyloidosis, as it was shown in recent studies. Compared to endomyocardial biopsy it is a non-invasive technique that is now more readily accessible and that seems to have an acceptable specificity.

Imaging inflammation in stroke using magnetic resonance imaging.

Stroke is the third leading cause of death, after myocardial infarction and cancer, and the leading cause of permanent disability in Western countries. Although anti-inflammatory drugs have shown very promising results in preclinical rodent studies, they appeared to be ineffective against stroke in clinical trials. In this context, non-invasive detection of inflammatory cells after brain ischemia could be helpful (i) to select patients who may benefit from anti-inflammatory treatment, and/or (ii) to target an adequate individualized therapeutic time window. Magnetic resonance imaging (MRI) coupled with injection of iron oxide nanoparticles, a contrast agent taken up by macrophages ex vivo and in vivo, appears to be a promising tool for this purpose. This review focuses on the use of this technique to image inflammation in pre-clinical and clinical studies of stroke. Despite current limitations, MRI of inflammation may become an important tool for the investigation of novel ischemic stroke therapeutics targeting inflammation.

Quantitative effects of cell internalization of two types of ultrasmall superparamagnetic iron oxide nanoparticles at 4.7 T and 7 T.

PURPOSE: MRI coupled with the intravenous injection of ultrasmall superparamagnetic particles of iron oxides (USPIOs) is a promising tool for the study of neuroinflammation. Quantification of the approximate number of magnetically labelled macrophages may provide an effective and efficient method for monitoring inflammatory cells. The purpose of the present study was to characterise the relaxation properties of macrophages labelled with two types of USPIOs, at 4.7 T and 7 T. METHODS: USPIO-labelled bone-marrow-derived macrophage phantoms were compared with phantoms of free dispersed USPIOs with the same global iron concentration, using multi-parametric (T1, T2 and T2) quantitative MRI. The same protocol was then evaluated in living mice after intracerebral injection of iron-labelled macrophages vs free iron oxide. RESULTS: A linear relationship was observed among R1, R2 and R2 values and iron concentration in vitro at 4.7 T and at 7 T. At a given field, T1 and T2 relaxivities of both types of USPIOs decreased following internalisation into macrophages, while T2 relaxivities increased. CONCLUSION: There was fair overall agreement between the theoretical number of injected cells and the number estimated from T2 quantification and in vitro calibration curves, supporting the validity of the present in vitro calibration curves for in vivo investigation.

Persistent left superior vena cava with absent right superior vena cava: a difficult cardiac pacemaker implantation.

An absent right superior vena cava associated with a persistent left superior vena cava (PLSVC) is a rare and generally asymptomatic congenital malformation. It is usually discovered incidentally during a pacemaker (PM) implantation. We report here a successful PM implantation using a left subclavian approach through the coronari sinus via a PLSVC, with a 2-year follow-up showing a still appropriate function of the device. We discuss the clinical usefulness of peripheral phlebography in the operating room for delineating precisely the venous anatomy, as well as the role of shaped stylets and active fixation leads to overcome technical difficulties.