Long-term clinical and ultrasound follow-up after transient perivascular inflammation of the carotid artery (TIPIC) syndrome: a multicenter study.

BACKGROUND: The present study aimed to describe the clinical and ultrasound (US) long-term follow-up of patients with transient perivascular inflammation of the carotid artery (TIPIC) syndrome and the risk of recurrence. METHODS: We enrolled patients with a definitive diagnosis of TIPIC syndrome who were included in a retrospective multicenter study. These patients were recontacted at least six months after the first TIPIC episode for a clinical and imaging follow-up. Each patient underwent a clinical evaluation through a tailored questionnaire as well as US imaging. RESULTS: Twenty-eight patients were enrolled with a median follow-up of 58.7 months (interquartile range = 8-121). Nineteen out of the 28 patients (67.8%) had residual pain, eight (28.6%) had experienced a clinical recurrence and 12 (42.9%) had a thickening of the carotid wall on US. No patients had neurological complication or other associated diseases. CONCLUSIONS: Patients with TIPIC syndrome have often residual pain and recurrence in about one quarter of cases but the long-term follow-up is in favor a benign self-limited pathology.Trial registration: ClinicalTrials.gov (identifier NCT03804112).

Co-registration with subtraction and color-coding or fusion improves the detection of new and growing lesions on follow-up MRI examination of patients with multiple sclerosis.

PURPOSE: The purpose of this study was to compare the performance of three magnetic resonance imaging (MRI) reading methods in the follow-up of patients with multiple sclerosis (MS). MATERIALS AND METHODS: This retrospective study included patients with MS who underwent two brain follow-up MRI examinations with three-dimensional fluid-attenuated inversion recovery (FLAIR) sequences between September 2016 and December 2019. Two neuroradiology residents independently reviewed FLAIR images using three post-processing methods including conventional reading (CR), co-registration fusion (CF), and co-registration subtraction with color-coding (CS), while being blinded to all data but FLAIR images. The presence and number of new, growing, or shrinking lesions were compared between reading methods. The reading time, reading confidence, and inter- and intra-observer agreements were also assessed. An expert neuroradiologist established the standard of reference. Statistical analyses were corrected for multiple testing. RESULTS: A total of 198 patients with MS were included. There were 130 women and 68 men, with a mean age of 41 ± 12 (standard deviation) years (age range: 21-79 years). Using CS and CF, more patients were detected with new lesions compared to CR (93/198 [47%] and 79/198 [40%] vs. 54/198 [27%], respectively; P < 0.01). The median number of new hyperintense FLAIR lesions detected was significantly greater using CS and CF compared to CR (2 [Q1, Q3: 0, 6] and 1 [Q1, Q3: 0, 3] vs. 0 [Q1, Q3: 0, 1], respectively; P < 0.001). The mean reading time was significantly shorter using CS and CF compared to CR (P < 0.001), with higher confidence in readings and higher inter- and intra-observer agreements. CONCLUSION: Post-processing tools such as CS and CF substantially improve the accuracy of follow-up MRI examinations in patients with MS while reducing reading time and increasing readers' confidence and reproducibility.

Contrast-Enhanced 3D Spin Echo T1-Weighted Sequence Outperforms 3D Gradient Echo T1-Weighted Sequence for the Detection of Multiple Sclerosis Lesions on 3.0 T Brain MRI.

BACKGROUND: Using reliable contrast-enhanced T1 sequences is crucial to detect enhancing brain lesions for multiple sclerosis (MS) at the time of diagnosis and over follow-up. Contrast-enhanced 3D gradient-recalled echo (GRE) T1-weighted imaging (WI) and 3D turbo spin echo (TSE) T1-WI are both available for clinical practice and have never been compared within the context of this diagnosis. PURPOSE: The aim of this study was to compare contrast-enhanced 3D GRE T1-WI and 3D TSE T1-WI for the detection of enhancing lesions in the brains of MS patients. METHODS: This single-center prospective study enrolled patients with MS who underwent a 3.0 T brain MRI from August 2017 to April 2021 for follow-up. Contrast-enhanced 3D GRE T1-WI and 3D TSE T1-WI were acquired in randomized order. Two independent radiologists blinded to all data reported all contrast-enhanced lesions in each sequence. Their readings were compared with a reference standard established by a third expert neuroradiologist. Interobserver agreement, contrast ratio, and contrast-to-noise ratio were calculated for both sequences. RESULTS: A total of 158 MS patients were included (mean age, 40 ± 11 years; 95 women). Significantly more patients had at least 1 contrast-enhanced lesion on 3D TSE T1-WI than on 3D GRE T1-WI for both readers (61/158 [38.6%] vs 48/158 [30.4%] and 60/158 [38.6%] vs 47/158 [29.7%], P < 0.001). Significantly more contrast-enhanced lesions per patient were detected on 3D TSE T1-WI (mean 2.47 vs 1.56 and 2.56 vs 1.39, respectively, P < 0.001). Interobserver agreement was excellent for both sequences, κ = 0.96 (confidence interval [CI], 0.91-1.00) for 3D TSE T1-WI and 0.92 (CI, 0.86-0.99) for 3D GRE T1-WI. Contrast ratio and contrast-to-noise ratio were significantly higher on 3D TSE T1-WI (0.84 vs 0.53, P < 0.001, and 87.9 vs 57.8, P = 0.03, respectively). CONCLUSIONS: At 3.0 T, contrast-enhanced 3D TSE-T1-WI supports the detection of significantly more enhancing lesions than 3D GRE T1-WI and should therefore be used for MS patients requiring contrast-enhanced examination.

Imaging of Cerebral Venous Thrombosis.

Cerebral venous thrombosis is a rare cause of stroke. Imaging is essential for diagnosis. Although digital subtraction angiography is still considered by many to be the gold standard, it no longer plays a significant role in the diagnosis of cerebral venous thrombosis. MRI, which allows for imaging the parenchyma, vessels and clots, and CT are the reference techniques. CT is useful in case of contraindication to MRI. After presenting the radio-anatomy for MRI, we present the different MRI and CT acquisitions, their pitfalls and their limitations in the diagnosis of cerebral venous thrombosis.

Epidemiology and Management of Cerebral Venous Thrombosis during the COVID-19 Pandemic.

Cerebral venous thrombosis (CVT) is a rare type of stroke that may cause an intracranial hypertension syndrome as well as focal neurological deficits due to venous infarcts. MRI with venography is the method of choice for diagnosis, and treatment with anticoagulants should be promptly started. CVT incidence has increased in COVID-19-infected patients due to a hypercoagulability state and endothelial inflammation. CVT following COVID-19 vaccination could be related to vaccine-induced immune thrombotic thrombocytopenia (VITT), a rare but severe complication that should be promptly identified because of its high mortality rate. Platelet count, D-dimer and PF4 antibodies should be dosed. Treatment with non-heparin anticoagulants and immunoglobulin could improve recuperation. Development of headache associated with seizures, impaired consciousness or focal signs should raise immediate suspicion of CVT. In patients who received a COVID-19 adenovirus-vector vaccine presenting thromboembolic events, VITT should be suspected and rapidly treated. Nevertheless, vaccination benefits clearly outweigh risks and should be continued.

Transient perivascular inflammation of the carotid artery (TIPIC) syndrome.

Background: The Transient Perivascular Inflammation of the Carotid artery (TIPIC) syndrome is presumably a very rare disease characterized by a local transient inflammation of the tissue around the carotid artery. Its pathophysiology remains unknown. We performed an updated study of TIPIC syndrome cases in the setting of a multinational collaborative study. Methods: This study was conducted as an observational multinational retrospective individual patient level cohort study. Information from all known cases diagnosed with TIPIC syndrome in the literature (2005-2020) was collected after a semi-structured literature search of PubMed and Web of Science. We also collected unpublished information of patients from French, Swiss, and Italian vascular medicine or radiology departments. Results: A total of 72 patients were included and served for data analysis: 42 (58.3%) were women; the mean age was 47.9 (SD=11.4) years. Symptoms were unilateral in 92% of patients and 81.4% required pain killers. At baseline, irrespective of the imaging method used, the median thickness of the carotid lesions was 5 (Q1-Q3: 4-7; range: 2-11) mm and the median length of the lesion was 20 (Q1-Q3: 10-30; range: 3-50) mm. We found a positive linear correlation between thickness and length. At follow-up, the thickness of the carotid lesions decreased to a median of 2 (Q1-Q3: 1-3; range: 0-6) mm; the length decreased to a median 10 (Q1-Q3: 5-15; range: 0-41) mm. A linear correlation between baseline and follow-up values was observed for both thickness and length measurements. Symptoms disappeared after a median of 14 (Q1-Q3: 10-15) days. Thirteen patients experienced a recurrence after a median follow-up of 6 (Q1-Q3: 2-12) months. Conclusions: The present analysis elucidates clinical and sonographic characteristics of TIPIC syndrome, indicating the benign nature of this condition. A future international registry will study the long-term course of the disease.

Validation of a multimodal algorithm for diagnosing giant cell arteritis with imaging.

PURPOSE: The purpose of this study was to identify which combination of imaging modalities should be used to obtain the best diagnostic performance for the non-invasive diagnosis of giant cell arteritis (GCA). MATERIALS AND METHODS: This IRB-approved prospective single-center study enrolled participants presenting with a suspected diagnosis of GCA from December 2014 to October 2017. Participants underwent high-resolution 3T magnetic resonance imaging (MRI), temporal and extra-cranial arteries ultrasound and retinal angiography (RA), prior to temporal artery biopsy (TAB). Diagnostic accuracy of each imaging modality alone, then a combination of several imaging modalities, was evaluated. Several algorithms were constructed to test optimal combinations using McNemar test. RESULTS: Forty-five participants (24 women, 21 men) with mean age of 75.4 ± 16 (SD) years (range: 59-94 years) were enrolled; of these 43/45 (96%) had ophthalmological symptoms. Diagnosis of GCA was confirmed in 25/45 (56%) patients. Sensitivity and specificity of MRI, ultrasound and RA alone were 100% (25/25; 95% CI: 86-100) and 86% (19/22; 95% CI: 65-97), 88% (22/25; 95% CI: 69-97) and 84% (16/19; 95% CI: 60-97), 94% (15/16; 95% CI: 70-100) and 74% (14/19; 95% CI: 49-91), respectively. Sensitivity, specificity, positive predictive and negative predictive values ranged from 95 to 100% (95% CI: 77-100), 67 to 100% (95% CI: 38-100), 81 to 100% (95% CI: 61-100) and 91 to 100% (95% CI: 59-100) when combining several imaging tests, respectively. The diagnostic algorithm with the overall best diagnostic performance was the one starting with MRI, followed either by ultrasound or RA, yielding 100% sensitivity (22/22; 95% CI: 85-100%) 100% (15/15; 95% CI: 78-100) and 100% accuracy (37/37; 95% CI: 91-100). CONCLUSION: The use of MRI as the first imaging examination followed by either ultrasound or RA reaches high degrees of performance for the diagnosis of GCA and is recommended in daily practice.

3D-Fast Gray Matter Acquisition with Phase Sensitive Inversion Recovery Magnetic Resonance Imaging at 3 Tesla: Application for detection of spinal cord lesions in patients with multiple sclerosis.

BACKGROUND AND PURPOSE: To compare 3D-Fast Gray Matter Acquisition with Phase Sensitive Inversion Recovery (3D-FGAPSIR) with conventional 3D-Short-Tau Inversion Recovery (3D-STIR) and sagittal T1-and T2-weighted MRI dataset at 3 Tesla when detecting MS spinal cord lesions. MATERIAL AND METHODS: This prospective single-center study was approved by an institutional review board and enrolled participants from December 2016 to August 2018. Two neuroradiologists blinded to all data, individually analyzed the 3D-FGAPSIR and the conventional datasets separately and in random order. Discrepancies were resolved by consensus by a third neuroradiologist. The primary judgment criterion was the number of MS spinal cord lesions. Secondary judgment criteria included lesion enhancement, lesion delineation, reader-reported confidence and lesion-to-cord-contrast-ratio. A Wilcoxon's test was used to compare the two datasets. RESULTS: 51 participants were included. 3D-FGAPSIR detected significantly more lesions than the conventional dataset (344 versus 171 respectively, p<0.001). Two participants had no detected lesion on the conventional dataset, whereas 3D-FGAPSIR detected at least one lesion. 3/51 participants had a single enhancing lesion detected by both datasets. Lesion delineation and reader-reported confidence were significantly higher with 3D-FGAPSIR: 4.5 (IQR 1) versus 2 (IQR 0.5), p<0.0001 and 4.5 (IQR 1) versus 2.5 (IQR 0.5), p<0.0001. Lesion-to-cord-contrast-ratio was significantly higher using 3D-FGAPSIR as opposed to 3D-STIR and T2: 1.4 (IQR 0,3) versus 0.4 (IQR 0,1) and 0.3 (IQR 0,1)(p = 0.04). Correlations with clinical data and inter- and intra-observer agreements were higher with 3D-FGAPSIR. CONCLUSION: 3D-FGAPSIR improved overall MS spinal cord lesion detection as compared to conventional set and detected all enhancing lesions.

Improved detection and characterization of arterial occlusion in acute ischemic stroke using contrast enhanced MRA.

BACKGROUND AND PURPOSE: To compare the accuracy and utility of contrast enhanced magnetic resonance angiography (MRA) (CEMRA) to Time of Flight MRA (TOF MRA) during detection and evaluation of occlusions on patients diagnosed with acute ischemic stroke (AIS). METHODS: This single-center study was approved by our local institutional research ethics board. From August 2014 to July 2016, 131 consecutive adult patients with confirmed AIS were included. Detection of an arterial occlusion and its characterization were evaluated independently with CEMRA or TOF MRA by two blinded neuroradiologists, then by consensus using all available MR sequences. A Cohen's Kappa coefficient (κ) and intra-class correlation coefficients (ICC) were used to compare the two techniques. RESULTS: There was substantial concordance in the detection of arterial occlusion between CEMRA and TOF MRA (κ = 0.75). TOF MRA was more likely to show an arterial occlusion than CEMRA (63 versus 52 patients respectively). There were 13 and 1 false positive arterial occlusion with TOF MRA and CEMRA respectively, and 1 false negative with TOF MRA. There was excellent concordance between the location of arterial occlusions and CEMRA and TOF MRA [κ = 0.89 (0.72-0.97)]. CEMRA was significantly more likely to allow measurement of the thrombus than was TOF MRA [38 (75%) versus 14 (22%)] (P < 0.0001). CONCLUSIONS: Our study showed that CEMRA imaging detected arterial occlusions better than TOF MRA in AIS patients and more precisely such that thrombus length and location could be known, which improves the patient's management and care.

Brief Report: Impact of ART Classes on the Increasing Risk of Cerebral Small-Vessel Disease in Middle-Aged, Well-Controlled, cART-Treated, HIV-Infected Individuals.

BACKGROUND: Cerebral small-vessel disease (CSVD) is a chronic disease accounting for one-third of strokes and the second etiology of dementia. Despite sustained immunovirological control, CSVD prevalence is doubled in middle-aged persons living with HIV (PLHIVs), even after adjustment for traditional cardiovascular risk factors. We aimed to investigate whether exposure to any antiretroviral drug class could be associated with an increasing risk of CSVD. METHODS: The MicroBREAK-2 case-control study (NCT02210130) enrolled PLHIVs aged 50 years and older, treated with combined antiretroviral therapy for ≥5 years, with plasma HIV load controlled for ≥12 months. Cases were PLHIVs with radiologically defined CSVD, and controls were CSVD-free PLHIVs matched for age (±5 years), sex, and year of HIV diagnosis (±5 years). Multivariable conditional logistic regression analyses focused on cumulative exposure to nucleoside reverse transcriptase inhibitors, non-nucleoside reverse transcriptase inhibitors, protease inhibitors and/or exposure to integrase inhibitors (yes or no), adjusted for hypertension, CD4 nadir, current CD4/CD8 ratio, and HIV transmission group. RESULTS: Between May 2014 and April 2017, 77 cases and 77 controls (85.7% males) were recruited. PLHIVs' median age was 57.6 years, and median HIV diagnosis year was 1992. The increasing risk of CSVD was not associated with exposure to any ART class. CONCLUSION: No deleterious effect of ART class exposure on the risk of CSVD was found for middle-aged treated PLHIVs.

Quality-based pharmacokinetic model selection on DCE-MRI for characterizing orbital lesions.

BACKGROUND: Although several studies have evaluated dynamic contrast-enhanced (DCE) MRI in the orbit, showing its utility when detecting and diagnosing orbital lesions, none have evaluated the pharmacokinetic models. PURPOSE: To provide a quality-based pharmacokinetic model selection for characterizing orbital lesions using DCE-MRI at 3.0T. STUDY TYPE: Prospective. POPULATION: From December 2015 to April 2017, 151 patients with an orbital lesion underwent MRI prior to surgery, including a high temporal resolution DCE sequence, divided into one training and one test dataset with 100 and 51 patients, respectively. FIELD STRENGTH/SEQUENCE: 3T/DCE. ASSESSMENT: Six different pharmacokinetic models were tested. STATISTICAL TESTS: Univariate and multivariate analyses were performed using Wilcoxon-2-sample tests and a logistic regression to compare parameters between malignant and benign tumors for each pharmacokinetic model for the whole cohort. Receiver operating characteristic (ROC) curve analyses were performed on the training dataset to determine area under curve (AUC) and optimal cutoff values for each pharmacokinetic model, then validated on the test dataset to calculate sensitivity, specificity, and accuracy. RESULTS: Regardless of the model, tissue blood flow and tissue blood volume values were significantly higher in malignant vs. benign lesions: 103.8-195.1 vs. 65-113.8, P [<10-4 -2.10-4 ] and 21.3-36.9 vs. 15.6-33.6, P [<10-4 -0.03] respectively. Extracellular volume fraction and permeability-surface area product or transfer constant appeared to be less relevant: 17.3-27.5 vs. 22.8-28.2, P [0.01-0.7], 1.7-4.9, P [0.2-0.9] and 9.5-38.8 vs. 8.1-22.8, P [<10-4 -0.6], respectively. ROC curves showed no significant differences in AUC between the different models. The two-compartment exchange (2CX) model ranked first for quality. DATA CONCLUSION: DCE MRI pharmacokinetic model-derived parameters appeared to be useful for discriminating benign from malignant orbital lesions. The 2CX model provided the best quality of modeling and should be recommended. Perfusion-related DCE parameters appeared to be significantly more relevant to the diagnostic process. Level of Evidence 1 Technical Efficacy: Stage 2 J. Magn. Reson. Imaging 2019;50:1514-1525.

Gray-level discretization impacts reproducible MRI radiomics texture features.

OBJECTIVES: To assess the influence of gray-level discretization on inter- and intra-observer reproducibility of texture radiomics features on clinical MR images. MATERIALS AND METHODS: We studied two independent MRI datasets of 74 lacrymal gland tumors and 30 breast lesions from two different centers. Two pairs of readers performed three two-dimensional delineations for each dataset. Texture features were extracted using two radiomics softwares (Pyradiomics and an in-house software). Reproducible features were selected using a combination of intra-class correlation coefficient (ICC) and concordance and coherence coefficient (CCC) with 0.8 and 0.9 as thresholds, respectively. We tested six absolute and eight relative gray-level discretization methods and analyzed the distribution and highest number of reproducible features obtained for each discretization. We also analyzed the number of reproducible features extracted from computer simulated delineations representative of inter-observer variability. RESULTS: The gray-level discretization method had a direct impact on texture feature reproducibility, independent of observers, software or method of delineation (simulated vs. human). The absolute discretization consistently provided statistically significantly more reproducible features than the relative discretization. Varying the bin number of relative discretization led to statistically significantly more variable results than varying the bin size of absolute discretization. CONCLUSIONS: When considering inter-observer reproducible results of MRI texture radiomics features, an absolute discretization should be favored to allow the extraction of the highest number of potential candidates for new imaging biomarkers. Whichever the chosen method, it should be systematically documented to allow replicability of results.

Magnetic resonance post-contrast vascular hyperintensities at 3 T: a new highly sensitive sign of vascular occlusion in acute ischaemic stroke.

BACKGROUND: Magnetic resonance imaging (MRI) is the diagnostic cornerstone for precisely identifying acute ischaemic strokes and locating vascular occlusions, especially since mechanical thrombectomy has become a reference treatment. We observed that a post-contrast three-dimensional turbo-spin-echo T1-weighted sequence showed striking post-contrast vascular hyperintensities (PCVH) in ischaemic territories. We aimed to evaluate the prevalence and the meaning of this finding. METHODS: This retrospective single centre study included 130 consecutive patients admitted for acute ischaemic stroke with a 3-T MRI performed in the first 12 h of symptom onset from September 2014 through September 2016. Two neuroradiologists blinded to clinical data analysed the first MRI assessments. The association between PCVH and clinical, radiological and follow-up findings was assessed, as well as inter- and intra-observer agreements. RESULTS: Of 130 patients, 105 (81%) had PCVH in the ischaemic territory. PCVH were associated with the presence of thrombus on susceptibility weighted imaging (p < 0.0001) and vascular occlusions on MR angiography (p < 0.0001). All patients with a visible thrombus had PCVH closely surrounding the clot. PCVH were associated with higher initial (p < 0.01) and follow-up (p < 0.01) National Institutes of Health Stroke Scale score, and higher mRS score (p < 0.05). Thrombectomy was the reference treatment for all patients with arterial occlusions. Inter- and intra-observer agreements for the detection of PCVH were excellent (κ = 0.95 and κ = 0.91, respectively). CONCLUSIONS: PCVH during acute strokes are a striking sensitive and reproducible tool for diagnosing and locating vascular occlusions. It may help triage patients who can benefit from thrombectomy. KEY POINTS: • Post-contrast vascular hyperintensities (PCVH) are a sensitive MR finding in acute stroke • PCVH are strongly associated with the presence and location of arterial occlusions • Inter- and intra-observer agreements for the detection of PCVH are excellent • PCVH are visible even in the case of significant motion artefacts • PCVH may help triage patients who can benefit from mechanical thrombectomy.

Silent Cerebral Small-Vessel Disease Is Twice as Prevalent in Middle-Aged Individuals With Well-Controlled, Combination Antiretroviral Therapy-Treated Human Immunodeficiency Virus (HIV) Than in HIV-Uninfected Individuals.

Background: Silent cerebral small-vessel disease (CSVD) is defined as white matter hyperintensities, silent brain infarction, or microbleeds. CSVD is responsible for future vascular events, cognitive impairment, frailty, and shorter survival. CSVD prevalence among middle-aged people living with well-controlled human immunodeficiency virus (HIV) infection (PLHIV) is unknown. Methods: The French National Agency for Research on AIDS and Viral Hepatitis (ANRS) EP51 Microvascular Brain Retina and Kidney Study (MicroBREAK; NCT02082574) is a cross-sectional study with prospective enrollment of treated PLHIV, ≥50 years old with viral load controlled for ≥12 months, and frequency age- and sex-matched HIV-uninfected controls (HUCs). It was designed to estimate CSVD prevalence on 3T magnetic resonance imaging (3D fluid-attenuated inversion recovery, transversal T2-weighted gradient-echo imaging and diffusion-weighted imaging), as diagnosed by 2 blinded neuroradiologists. A logistic regression model was used to assess the impact of HIV on CSVD after adjustment for traditional risk factors. Results: Between June 2013 and May 2016, 456 PLHIV and 154 HUCs were recruited. Median age was 56 and 58 years, respectively (P = .001), among whom 84.9% and 77.3%, respectively (P = .030), were men. CSVD was detected in 51.5% of PLHIV and 36.4% of HUCs with an adjusted odds ratio (aOR) of 2.3. The HIV impact differed according to age, with aOR values of 5.3, 3.7, and 1.0 for age groups <54, 54-60, and >60 years, respectively (P = .022). Older age, hypertension, and lower CD4 cell count nadir were independently associated with a higher risk of CSVD among PLHIV. Conclusions: HIV is an independent risk factor for CSVD. Despite sustained immunovirological control, the CSVD prevalence was twice as high among middle-aged PLHIV than HUCs. Clinical Trials Registration: NCT02082574.

Repeatability of apparent diffusion coefficient and intravoxel incoherent motion parameters at 3.0 Tesla in orbital lesions.

OBJECTIVES: To evaluate repeatability of intravoxel incoherent motion (IVIM) diffusion-weighted imaging (DWI) parameters in the orbit. METHODS: From December 2015 to March 2016, 22 patients were scanned twice using an IVIM sequence with 15b values (0-2,000 s/mm2) at 3.0T. Two readers independently delineated regions of interest in an orbital mass and in different intra-orbital and extra-orbital structures. Short-term test-retest repeatability and inter-observer agreement were assessed using the intra-class correlation coefficient (ICC), the coefficient of variation (CV) and Bland-Altman limits of agreements (BA-LA). RESULTS: Test-retest repeatability of IVIM parameters in the orbital mass was satisfactory for ADC and D (mean CV 12% and 14%, ICC 95% and 93%), poor for f and D*(means CV 43% and 110%, ICC 90% and 65%). Inter-observer repeatability agreement was almost perfect in the orbital mass for all the IVIM parameters (ICC = 95%, 93%, 94% and 90% for ADC, D, f and D*, respectively). CONCLUSIONS: IVIM appeared to be a robust tool to measure D in orbital lesions with good repeatability, but this approach showed a poor repeatability of f and D*. KEY POINTS: • IVIM technique is feasible in the orbit. • IVIM has a good-acceptable repeatability of D (CV range 12-25 %). • IVIM interobserver repeatability agreement is excellent (ICC range 90-95 %). • f or D* provide higher test-retest and interobserver variabilities.

Study of the posterior communicating arteries of the circle of willis in idiopathic sudden sensorineural hearing loss.

OBJECTIVES: To evaluate the incidence of non-functioning posterior communicating arteries (PCoA) of the circle of Willis in patients presenting with idiopathic sudden sensorineural hearing loss (SSHL). BACKGROUND: Pathogenesis of SSHL remains unclear despite several theories. A strong association between non-functioning PCoA of the circle of Willis and SSHL has been recently suggested, supporting the theory of vascular disorders. SETTING: Tertiary referral center. PATIENTS AND METHODS: Ultrasonographic Doppler flow measurements of the vertebrobasilar system were performed prospectively in 27 consecutive patients with idiopathic SSHL and in 27 healthy subjects. RESULTS: A non-functioning PCoA was found in 4 patients with idiopathic SSHL and in 4 cases in the control group. CONCLUSION: The results of our study did not show any association between non-functioning PCoA of the circle of Willis and idiopathic SSHL, contrasting with previous data. We do not recommend adding routine transcranial Doppler ultrasonography in the test-battery for SSHL.

Hemostatic closure device after carotid puncture for stent and coil placement in an intracranial aneurysm: technical note.

A 71-year-old female patient presented with a wide-necked carotid cavernous aneurysm for which stent and coil placement was planned. Arterial tortuosity required direct puncture of the common carotid artery for access. The procedure was performed while the patient was receiving antiplatelet and anticoagulative therapy. To avoid potentially hazardous and prolonged carotid compression, a closure device (Angio-Seal) was used at the end of the procedure. The postoperative period was clinically uneventful. Sonographic and angiographic follow-up of the carotid artery were performed.