Functional connectivity of the amygdala subnuclei in various mood states of bipolar disorder.

Amygdala functional dysconnectivity lies at the heart of the pathophysiology of bipolar disorder (BD). Recent preclinical studies suggest that the amygdala is a heterogeneous group of nuclei, whose specific connectivity could drive positive or negative emotional valence. We investigated functional connectivity (FC) changes within these circuits emerging from each amygdala's subdivision in 127 patients with BD in different mood states and 131 healthy controls (HC), who underwent resting-state functional MRI. FC was evaluated between lateral and medial nuclei of amygdalae, and key subcortical regions of the emotion processing network: anterior and posterior parts of the hippocampus, and core and shell parts of the nucleus accumbens. FC was compared across groups, and subgroups of patients depending on their mood states, using linear mixed models. We also tested correlations between FC and depression (MADRS) and mania (YMRS) scores. We found no difference between the whole sample of BD patients vs. HC but a significant correlation between MADRS and right lateral amygdala /right anterior hippocampus, right lateral amygdala/right posterior hippocampus and right lateral amygdala/left anterior hippocampus FC (r = -0.44, r = -0.32, r = -0.27, respectively, all pFDR<0.05). Subgroup analysis revealed decreased right lateral amygdala/right anterior hippocampus and right lateral amygdala/right posterior hippocampus FC in depressed vs. non-depressed patients and increased left medial amygdala/shell part of the left nucleus accumbens FC in manic vs non-manic patients. These results demonstrate that acute mood states in BD concur with FC changes in individual nuclei of the amygdala implicated in distinct emotional valence processing. Overall, our data highlight the importance to consider the amygdala subnuclei separately when studying its FC patterns including patients in distinct homogeneous mood states.

High diagnostic accuracy of T2FLAIR at 3 T in the detection of optic nerve head edema in acute optic neuritis.

OBJECTIVES: Optic nerve head edema (ONHE) detected by fundoscopy is observed in one-third of patients presenting optic neuritis (ON). While ONHE is an important semiological feature, the correlation between ONHE and optic nerve head MRI abnormalities (ONHMA), sometimes called "optic nerve head swelling," remains unknown. Our study aimed to assess the diagnostic accuracy of T2 fluid-attenuated inversion recovery (FLAIR) MRI sequence in detecting ONHE in patients with acute ON. METHODS: In the present single-center study, data were extracted from two prospective cohort studies that consecutively included adults with a first episode of acute ON treated between 2015 and 2020. Two experienced readers blinded to study data independently analyzed imaging. A senior neuroradiologist resolved any discrepancies. The primary judgment criterion of ONHMA was assessed as optic nerve head high signal intensity on gadolinium-enhanced T2FLAIR MRI sequence. Its diagnostic accuracy was evaluated with both the gold standard of ONHE on fundus photography (FP) and peripapillary retinal nerve fiber layer thickening on optic coherence tomography (OCT). RESULTS: A total of 102 patients were included, providing 110 affected and 94 unaffected optic nerves. Agreement was high between the different modalities: 92% between MRI and FP (k = 0.77, 95% CI: 0.67-0.88) and 93% between MRI and OCT (k = 0.77, 95% CI: 0.67-0.87). MRI sensitivity was 0.84 (95% CI: 0.70-0.93) and specificity was 0.94 (95% CI: 0.89-0.97) when compared with the FP. CONCLUSION: Optic nerve head high T2FLAIR signal intensity corresponds indeed to the optic nerve head edema diagnosed by the ophthalmologists. MRI is a sensitive tool for detecting ONHE in patients presenting acute ON. CLINICAL RELEVANCE STATEMENT: In patients with optic neuritis the high T2FLAIR (fluid-attenuated inversion recovery) signal intensity of the optic nerve head corresponds indeed to optic nerve head edema, which is a useful feature in optic neuritis etiological evaluation and treatment. KEY POINTS: Optic nerve head edema is a prominent clinical feature of acute optic neuritis and is usually diagnosed during dilated or non-dilated eye fundus examination. Agreement was high between magnetic resonance imaging, fundus photography, and optical coherence tomography. Optic nerve head high T2 fluid attenuation inversion recovery signal intensity is a promising detection tool for optic nerve head edema in patients presenting acute optic neuritis.

Reproducibility and accuracy of vessel wall MRI in diagnosing giant cell arteritis: a study with readers of varying expertise.

OBJECTIVE: To evaluate the reproducibility of vessel wall magnetic resonance imaging (VW-MRI) in diagnosing giant cell arteritis (GCA) among groups of radiologists with varying levels of expertise. METHODS: This institutional review board-approved retrospective single-center study recruited patients with suspected GCA between December 2014 and September 2021. Patients underwent 3 -T VW-MRI before temporal artery biopsy. Ten radiologists with varying levels of expertise, blinded to all data, evaluated several intracranial and extracranial arteries to assess GCA diagnosis. Interobserver reproducibility and diagnostic performance were evaluated. RESULTS: Fifty patients (27 women and 23 men) with a mean age of 75.9 ± 9 years were included. Thirty-one of 50 (62%) had a final diagnosis of GCA.VW-MRI had an almost perfect reproducibility among expert readers (kappa = 0.93; 95% CI 0.77-1) and substantial reproducibility among all readers, junior and non-expert senior readers (kappa = 0.7; 95% CI 0.66-0.73; kappa = 0.67 95% CI 0.59-0.74; kappa = 0.65; 95% CI 0.43-0.88 respectively) when diagnosing GCA. Substantial interobserver agreement was observed for the frontal branch of superficial temporal artery. Moderate interobserver agreement was observed for the superficial temporal artery and its parietal branch, as well as ophthalmic arteries in all groups of readers. Sensitivity, specificity, positive predictive value, negative predictive value, and accuracy varied depending on the group of readers. CONCLUSION: VW-MRI is a reproducible and accurate imaging modality for detecting GCA, even among less-experienced readers. This study advocates for the use of VW-MRI when diagnosing GCA even in less-experienced centers. CLINICAL RELEVANCE STATEMENT: VW-MRI is a reproducible and accurate imaging modality for detecting GCA, even among less-experienced readers, and it could be used as a first-line diagnostic tool for GCA in centers with limited expertise in GCA diagnosis. KEY POINTS: • Vessel wall magnetic resonance imaging (VW-MRI) is a reproducible and accurate imaging modality for detecting giant cell arteritis (GCA) in both extracranial and intracranial arteries. • The reproducibility of vessel wall magnetic resonance imaging for giant cell arteritis diagnosis was high among expert readers and moderate among less-experienced readers. • The use of vessel wall magnetic resonance imaging for giant cell arteritis diagnosis can be recommended even in centers with less-experienced readers.

A signature of structural MRI features at 3 Tesla allows an accurate characterization of orbital cavernous venous malformation.

OBJECTIVES: To differentiate OCVM from other orbital lesions using structural MRI. METHODS: This IRB-approved a historical-prospective cohort single-center analysis of a prospective cohort that included consecutive adult patients presenting with an orbital lesion undergoing a 3T MRI before surgery from December 2015 to May 2021. Two readers blinded to all data read all MRIs assessing structural MRI characteristics. A univariate analysis followed by a stepwise multivariate analysis identified structural MRI features showing the highest sensitivity and specificity when diagnosing OCVM. RESULTS: One hundred ninety-one patients with 30/191 (16%) OCVM and 161/191 (84%) other orbital lesions were included. OCVM were significantly more likely to present with a higher signal intensity than that of the cortex on T2WI: 26/29 (89.7%) versus 28/160 (17.5%), p < 0.001, or with a chemical shift artifact (CSA): 26/29 (89.7%) versus 16/155 (10.3%), p < 0.001, or to present with a single starting point of enhancement, as compared to other orbital lesions: 18/29 (62.1%) versus 4/159 (2.5%), p = 0.001. The step-wise analysis identified 2 signatures increasing performances. Signature 1 combined a higher signal intensity than that of the cortex on T2WI and a CSA. Signature 2 included these two features and the presence of a single starting point of enhancement. Sensitivity, specificity, and accuracy were 0.83, 0.94, and 0.92 for signature 1 and 0.97, 0.93, and 0.93 for signature 2, respectively. CONCLUSION: Structural MRI yields high sensitivity and specificity when diagnosing OCVM. KEY POINTS: • Structural MRI shows high sensitivity and specificity when diagnosing orbital cavernous venous malformation. • We identified two signatures combining structural MRI features which might be used easily in routine clinical practice. • The combination of higher signal intensity of the lesion as compared to the cortex on T2WI and of a chemical shift artifact yields a sensitivity and specificity of 0.83 and 0.94 for the diagnosis of orbital cavernous venous malformation, respectively.

Orbital magnetic resonance imaging of giant cell arteritis with ocular manifestations: a systematic review and individual participant data meta-analysis.

OBJECTIVES: We conducted a systematic review and individual participant data meta-analysis of publications reporting the ophthalmologic presentation, clinical exam, and orbital MRI findings in patients with giant cell arteritis and ocular manifestations. METHODS: PubMed and Cochrane databases were searched up to January 16, 2022. Publications reporting patient-level data on patients with ophthalmologic symptoms, imaged with orbital MRI, and diagnosed with biopsy-proven giant cell arteritis were included. Demographics, clinical symptoms, exam, lab, imaging, and outcomes data were extracted. The methodological quality and completeness of reporting of case reports were assessed. RESULTS: Thirty-two studies were included comprising 51 patients (females = 24; median age, 76 years). Vision loss (78%) and headache (45%) were commonly reported visual and cranial symptoms. Ophthalmologic presentation was unilateral (41%) or bilateral (59%). Fundus examination most commonly showed disc edema (64%) and pallor (49%). Average visual acuity was very poor (2.28 logMAR ± 2.18). Diagnoses included anterior (61%) and posterior (16%) ischemic optic neuropathy, central retinal artery occlusion (8%), and orbital infarction syndrome (2%). On MRI, enhancement of the optic nerve sheath (53%), intraconal fat (25%), and optic nerve/chiasm (14%) was most prevalent. Among patients with monocular visual symptoms, 38% showed pathologic enhancement in the asymptomatic orbit. Six of seven cases reported imaging resolution after treatment on follow-up MRIs. CONCLUSIONS: Vision loss, pallid disc edema, and optic nerve sheath enhancement are the most common clinical, fundoscopic, and imaging findings reported in patients diagnosed with giant cell arteritis with ocular manifestations, respectively. MRI may detect subclinical inflammation and ischemia in the asymptomatic eye and may be an adjunct diagnostic tool. CLINICAL RELEVANCE STATEMENT: Brain and orbital MRIs may have diagnostic and prognostic roles in patients with suspected giant cell arteritis who present with ophthalmic symptoms.

Leptomeningeal enhancement on post-contrast FLAIR images for early diagnosis of Susac syndrome.

BACKGROUND: Leptomeningeal enhancement (LME) is a key feature of Susac syndrome (SuS) but is only occasionally depicted on post-contrast T1-weighted images (T1-WI). OBJECTIVE: As post-contrast fluid-attenuated inversion recovery (FLAIR) may be more sensitive, our aim was to assess LME in SuS on this sequence. METHODS: From 2010 to 2020, 20 patients with definite SuS diagnosis were retrospectively enrolled in this multicentre study. Two radiologists independently assessed the number of LME on post-contrast FLAIR and T1-WI acquisitions performed before any treatment. A chi-square test was used to compare both sequences and the interrater agreement was calculated. RESULTS: Thirty-five magnetic resonance imagings (MRIs) were performed before treatment, including 19 post-contrast FLAIR images in 17 patients and 25 post-contrast T1-WI in 19 patients. In terms of patients, LME was observed on all post-contrast FLAIR, contrary to post-contrast T1-WI (17/17 (100%) vs. 15/19 (79%), p < 0.05). In terms of sequences, LME was observed on all post-contrast FLAIR, contrary to post-contrast T1-WI (19/19 (100%) vs. 16/25 (64%), p < 0.005). LME was disseminated at both supratentorial (19/19) and infratentorial (18/19) levels on post-contrast FLAIR, contrary to post-contrast T1-WI (3/25 and 9/25, respectively). Interrater agreement was excellent for post-contrast FLAIR (κ = 0.95) but only moderate for post-contrast T1-WI (κ = 0.61). CONCLUSION: LME was always observed and easily visible on post-contrast FLAIR images prior to SuS treatment. In association with other MRI features, it is highly indicative of SuS.

Early diffusion-weighted MRI at 3 Tesla detects ischemic changes of the optic nerve in anterior ischemic optic neuropathy.

OBJECTIVES: To assess the impact of timing from visual symptoms' onset to diffusion-weighted (DW) 3 T MRI completion to detect ischemic changes of the optic disc and optic nerve in AION patients. METHODS: This IRB-approved retrospective single-center study included 3 T MRI data from 126 patients with AION and 111 controls with optic neuritis treated between January 2015 and May 2020. Two radiologists blinded to all data individually analyzed imaging. A senior neuroradiologist resolved any discrepancies by consensus. The primary judgment criterion was the restricted diffusion of the optic disc and/or the optic nerve assessed subjectively on the ADC maps. ADC values were also measured. Spearman rank correlations were used to examine the relationships between timing from visual symptoms' onset to MRI completion and both the restricted diffusion and the ADC values. RESULTS: One hundred twenty-six patients (47/126 [37.3%] women and 79/126 [62.7%] men, mean age 69.1 ± 13.7 years) with AION were included. Restricted diffusion of the optic disc in AION eyes was more frequent in the early MRI group than in the late MRI group: 35/49 (71.4%) eyes versus 3/83 (3.6%) eyes, p < 0.001. ADC values of the pathological optic discs and optic nerves were lower in the early MRI group than in the late MRI group: 0.61 [0.52-0.94] × 10-3 mm2/s versus 1.28 [1.01-1.44] × 10-3 mm2/s, p < 0.001, and 0.74 [0.61-0.88] × 10-3 mm2/s versus 0.89 [0.72-1.10] × 10-3 mm2/s, p < 0.001, respectively. CONCLUSIONS: DWI MRI showed good diagnostic performance to detect AION when performed early after the onset of visual symptoms. KEY POINTS: • Restricted diffusion of the optic disc in eyes affected by AION was significantly more likely to be observed in patients who had undergone MRI within 5 days after onset of visual symptoms. • ADC values of the pathological optic discs and optic nerves were significantly lower in patients who had undergone MRI within 5 days after onset of visual symptoms of AION: 0.61 × 10-3 mm2/s versus 1.28 × 10-3 mm2/s, p < 0.001, and 0.74 × 10-3 mm2/s versus 0.89 × 10-3 mm2/s, p < 0.001, respectively. • The optimal threshold for timing from visual symptoms' onset to MRI completion to detect restricted diffusion of the optic disc and/or optic nerve was 5 days, with an AUC of 0.88 (CI95%: 0.82-0.94).

Use of Retinal Angiography and MRI in the Diagnosis of Giant Cell Arteritis With Early Ophthalmic Manifestations.

BACKGROUND: Giant cell arteritis (GCA) is a vasculitis often revealed by visual signs. Diagnosis is challenging and urgent. Retinal angiography (RA) and MRI allow effective diagnosis. We compared those and proposed an imaging-based approach to diagnose GCA in ophthalmological practice. METHODS: We conducted a retrospective study based on the data collected from patients suspected to have GCA on ophthalmological findings. Fluorescein (FA) and indocyanine green (ICG) RAs and MRI were performed and compared with final diagnosis. RESULTS: Among the 41 patients included, 25 were diagnosed with GCA. Sensitivities and specificities of FA and ICG were not different. MRI showed a higher sensitivity and specificity. The approach consisting in performing RA followed by MRI provided a better accuracy. CONCLUSION: Our study shows that RA can be supplemented by MRI in a specialized center to provide the most accurate diagnosis in GCA revealed by visual signs.

Intravoxel incoherent motion (IVIM) 3 T MRI for orbital lesion characterization.

OBJECTIVES: To determine the diagnostic accuracy of MRI intravoxel incoherent motion (IVIM) when characterizing orbital lesions, which is challenging due to a wide range of locations and histologic types. METHODS: This IRB-approved prospective single-center study enrolled participants presenting with an orbital lesion undergoing a 3-T MRI prior to surgery from December 2015 to July 2019. An IVIM sequence with 15 b values ranging from 0 to 2000 s/mm2 was performed. Two neuroradiologists, blinded to clinical data, individually analyzed morphological MRIs. They drew one region of interest inside each orbital lesion, providing apparent diffusion coefficient (ADC), true diffusion coefficient (D), perfusion fraction (f), and pseudodiffusion coefficient (D*) values. T test, Mann-Whitney U test, and receiver operating characteristic curve analyses were performed to discriminate between orbital lesions and to determine the diagnostic accuracy of the IVIM parameters. RESULTS: One hundred fifty-six participants (84 women and 72 men, mean age 54.4 ± 17.5 years) with 167 orbital lesions (98/167 [59%] benign lesions including 54 orbital inflammations and 69/167 [41%] malignant lesions including 32 lymphomas) were included in the study. ADC and D were significantly lower in malignant than in benign lesions: 0.8 × 10-3 mm2/s [0.45] versus 1.04 × 10-3 mm2/s [0.33], p < 0.001, and 0.75 × 10-3 mm2/s [0.40] versus 0.98 × 10-3 mm2/s [0.42], p < 0.001, respectively. D* was significantly higher in malignant lesions than in benign ones: 12.8 × 10-3 mm2/s [20.17] versus 7.52 × 10-3 mm2/s [7.57], p = 0.005. Area under curve was of 0.73, 0.74, 0.72, and 0.81 for ADC, D, D*, and a combination of D, f, and D*, respectively. CONCLUSIONS: Our study showed that IVIM might help better characterize orbital lesions. KEY POINTS: • Intravoxel incoherent motion (IVIM) helps clinicians to assess patients with orbital lesions. • Intravoxel incoherent motion (IVIM) helps clinicians to characterize orbital lymphoma versus orbital inflammation. • Management of patients becomes more appropriate.

Dixon-T2WI magnetic resonance imaging at 3 tesla outperforms conventional imaging for thyroid eye disease.

OBJECTIVES: To determine the diagnostic performances of a single Dixon-T2-weighted imaging (WI) sequence compared to a conventional protocol including T1-, T2-, and fat-suppressed T2-weighted MRI at 3 T when assessing thyroid eye disease (TED). MATERIALS AND METHODS: This IRB-approved prospective single-center study enrolled participants presenting with confirmed TED from April 2015 to October 2019. They underwent an MRI, including a conventional protocol and a Dixon-T2WI sequence. Two neuroradiologists, blinded to all data, read both datasets independently and randomly. They assessed the presence of extraocular muscle (EOM) inflammation, enlargement, fatty degeneration, or fibrosis as well as the presence of artifacts. The Wilcoxon signed-rank test was used. RESULTS: Two hundred six participants were enrolled (135/206 [66%] women, 71/206 [34%] men, age 52.3 ± 13.2 years). Dixon-T2WI was significantly more likely to detect at least one inflamed EOM as compared to the conventional set (248/412 [60%] versus 228/412 [55%] eyes; (p = 0.02). Dixon-T2WI was more sensitive and specific than the conventional set for assessing muscular inflammation (100% versus 94.7% and 71.2% versus 68.5%, respectively). Dixon-T2WI was significantly less likely to show major or minor artifacts as compared to fat-suppressed T2WI (20/412 [5%] versus 109/412 [27%] eyes, p < 0.001, and 175/412 [42%] versus 257/412 [62%] eyes, p < 0.001). Confidence was significantly higher with Dixon-T2WI than with the conventional set (2.35 versus 2.24, p = 0.003). CONCLUSION: Dixon-T2WI showed higher sensitivity and specificity and showed fewer artifacts than a conventional protocol when assessing thyroid eye disease, in addition to higher self-reported confidence. KEY POINTS: • Dixon-T2WI has better sensitivity and specificity than a conventional protocol for assessing inflamed extraocular muscles in patients with thyroid eye disease. • Dixon-T2WI shows significantly fewer artifacts than fat-suppressed T2WI. • Dixon-T2WI is faster and is associated with significantly higher self-reported reader confidence as compared to a conventional protocol when assessing inflammatory extraocular muscles.

High-resolution MRI demonstrates signal abnormalities of the 3rd cranial nerve in giant cell arteritis patients with 3rd cranial nerve impairment.

OBJECTIVE: To determine the sensitivity and specificity of high-resolution (HR) MRI for detecting signal abnormalities of cranial nerves (CN) in giant cell arteritis (GCA) patients presenting with diplopia. METHODS: This IRB-approved retrospective single-center study included GCA patients who underwent 3-T HR MRI from December 2014 to January 2020. Two radiologists, blinded to all data, individually assessed for the presence of enhancement of the 3rd, 4th, and/or 6th CN on post-contrast HR imaging and high signal intensity on HR T2-WI, for signal abnormalities of extraocular muscles and the brainstem, and for inflammatory changes of the ophthalmic and extracranial arteries. A Fisher's exact test was used to compare patients with or without diplopia. RESULTS: In total, 64 patients (42/64 (66%) women and 22/64 (34%) men, mean age 76.3 ± 8 years) were included. Of the 64 patients, 14 (21.9%) presented with diplopia. Third CN enhancement was detected in 7/8 (87.5%) patients with 3rd CN impairment, as compared to no patients with 4th or 6th CN impairment or to patients without diplopia (p < 0.001). Third CN abnormal high signal intensity on HR T2-WI was detected in 4/5 patients (80%) with 3rd CN impairment versus none of other patients (p < 0.001). Sensitivity, specificity, positive predictive value, and negative predictive value for detecting 3rd CN signal abnormalities were of 0.88, 1, 1, and 0.99 and 0.8, 1, 1, and 0.98 for post-contrast HR imaging and HR T2-WI, respectively. CONCLUSIONS: HR MRI had excellent diagnostic sensitivity and specificity when detecting signal abnormalities of the 3rd CN in GCA patients presenting with 3rd CN impairment. KEY POINTS: • Third cranial nerve enhancement was detected in all patients with 3rd cranial nerve impairment except for one with transient diplopia. • The "check mark sign" might be useful to identify 3rd cranial nerve signal abnormalities in the orbital apex. • No signal abnormalities of the 4th or 6th cranial nerves could be detected on high-resolution MRI.

Vascular origin in acute transient visual disturbance: A prospective study.

BACKGROUND AND PURPOSE: This study was undertaken to validate a clinical score of vascular origin in patients with acute transient visual disturbances (TVDs) without diplopia. METHODS: We conducted a prospective study in an ophthalmology emergency department and a transient ischemic attack (TIA) clinic. Patients underwent clinical evaluation including a tailored questionnaire, brain, vascular, and ophthalmologic investigations, and 3-month follow-up. TVDs were classified according to vascular or nonvascular origin by three independent experts based on all clinical, cerebrovascular, and ophthalmologic investigations, but blind to the questionnaire results. A clinical score was derived based on clinical variables independently associated with a vascular origin, and was externally validated in an independent cohort. RESULTS: An ischemic origin of TVD was found in 45% (67/149) of patients in the derivation cohort. Age and six questions were independently associated with an ischemic origin. A nine-point score (≥70 years old = 2; monocular visual loss = 2; black or white vision = 1; single episode = 1; lack of headache = 2; diffuse, constricted, altitudinal, or lateralized visual loss pattern on drawings = 1) showed good discriminative power in identifying ischemic origin (c-statistic = 0.82) and was replicated in the validation cohort (n = 130, 25% of ischemic origin, c-statistic = 0.75). With a score ≥ 4, sensitivity was 85% (95% confidence interval = 68-95) and specificity was 52% (95% confidence interval = 41-62). In both cohorts, ophthalmologic evaluation found a vascular cause in 4% and was noncontributive in 85%. After 3 months, no patients had a stroke, TIA, or retinal infarct. CONCLUSIONS: Our score may assist in predicting a vascular origin of TVD. Ophthalmologic evaluation, when not readily available, should not delay the neurovascular evaluation.

Increased diagnostic accuracy of giant cell arteritis using three-dimensional fat-saturated contrast-enhanced vessel-wall magnetic resonance imaging at 3 T.

OBJECTIVES: To compare the diagnostic accuracy of 3D versus 2D contrast-enhanced vessel-wall (CE-VW) MRI of extracranial and intracranial arteries in the diagnosis of GCA. METHODS: This prospective two-center study was approved by a national research ethics board and enrolled participants from December 2014 to October 2017. A protocol including both a 2D and a 3D CE-VW MRI at 3 T was performed in all patients. Two neuroradiologists, blinded to clinical data, individually analyzed separately and in random order 2D and 3D sequences in the axial plane only or with reformatting. The primary judgment criterion was the presence of GCA-related inflammatory changes of extracranial arteries. Secondary judgment criteria included inflammatory changes of intracranial arteries and the presence of artifacts. A McNemar's test was used to compare 2D to 3D CE-VW MRIs. RESULTS: Seventy-nine participants were included in the study (42 men and 37 women, mean age 75 (± 9.5 years)). Fifty-one had a final diagnosis of GCA. Reformatted 3D CE-VW was significantly more sensitive than axial-only 3D CE-VW or 2D CE-VW when showing inflammatory change of extracranial arteries: 41/51(80%) versus 37/51 (73%) (p = 0.046) and 35/50 (70%) (p = 0.03). Reformatted 3D CE-VW was significantly more specific than 2D CE-VW: 27/27 (100%) versus 22/26 (85%) (p = 0.04). 3D CE-VW showed higher sensitivity than 2D CE-VW when detecting inflammatory changes of intracranial arteries: 10/51(20%) versus 4/50(8%), p = 0.01. Interobserver agreement was excellent for both 2D and 3D CE-VW MRI: κ = 0.84 and 0.82 respectively. CONCLUSIONS: 3D CE-VW MRI supported more accurate diagnoses of GCA than 2D CE-VW. KEY POINTS: • 3D contrast-enhanced vessel-wall magnetic resonance imaging is a high accuracy, non-invasive diagnostic tool used to diagnose giant cell arteritis. • 3D contrast-enhanced vessel-wall imaging is feasible for clinicians to complete within a relatively short time, allowing immediate assessment of extra and intracranial arteries. • 3D contrast-enhanced vessel-wall magnetic resonance imaging might be considered a diagnostic tool when intracranial manifestation of GCA is suspected.

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.

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.

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.

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.

Remote brain microhaemorrhages may predict haematoma in glioma patients treated with radiation therapy.

OBJECTIVES: To evaluate the prevalence of cerebral remote microhaemorrhages (RMH) and remote haematomas (RH) using magnetic resonance susceptibility-weighted imaging (SWI) among patients treated for gliomas during follow-up. METHODS: We conducted a retrospective single centre longitudinal study on 58 consecutive patients treated for gliomas from January 2009 through December 2010. Our institutional review board approved this study. We evaluated the presence and number of RMH and RH found outside the brain tumour on follow-up MR imaging. We performed univariate and bivariate analyses to identify predictors for RMH and RH and Kaplan-Meier survival analysis techniques. RESULTS: Twenty-five (43%) and four patients (7%) developed at least one RMH or RH, respectively, during follow-up. The risk was significantly higher for patients who received radiation therapy (49% and 8% versus 0%) (p = 0.02). The risk of developing RH was significantly higher in patients with at least one RMH and a high burden of RMH. The mean age of those presenting with at least one RMH or RH was significantly lower. CONCLUSIONS: RMH were common in adult survivors of gliomas who received radiation therapy and may predict the onset of RH during follow-up, mainly in younger patients. KEY POINTS: • Brain RMH and RH are significantly more likely to occur after RT. • RMH occur in almost half of the patients treated with RT. • RMH and RH are significantly more frequent in younger patients. • RH occur only in patients with RMH.

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.