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.

Evaluation of a uniplanar pupil expansion ring in small-pupil cataract surgery: a feasibility study.

PURPOSE: The aim of this study was to evaluate the effectiveness of a disposable uniplanar pupil expansion device in small-pupil cataract surgery. METHODS: This is a feasibility study carried out at the Rothschild Foundation, Paris, France. Patients undergoing routine cataract surgery with a dilated pupil size < 6 mm, and who agreed to participate in the study were included. The trial enrolled 25 patients, of whom 21 proceeded to cataract surgery using the pupil expansion device to be evaluated. The pupil diameter was measured at defined stages during the cataract surgery, which was performed by a single surgeon, in a single center setting. The 1st generation Bhattacharjee pupil expansion ring was used if the preoperative pupil size was < 6 mm. Intraoperative and postoperative adverse events were recorded. RESULTS: Pupil size immediately after the Bhattacharjee ring implantation was ≥ 6 mm for 15 eyes (71.4%). The mean dilated pupil size before ring insertion was 4.5 ± 0.8 mm (range 2.5-5.8 mm), and the mean pupil size after ring insertion was 6.1 ± 0.3 mm (range 5.9-6.8 mm). Mean pupil size following removal of the ring was 4.2 ± 0.8 mm (range 2.5-5.4 mm). Two adverse events occurred during the surgeries: 1 Bhattacharjee ring broke prior to implantation, and 1 implanted Bhattacharjee ring was unstable and removed before the end of the surgery. No postoperative adverse event was recorded. CONCLUSIONS: The Bhattacharjee ring is an effective pupil expansion device, which facilitates stable pupil expansion during cataract surgery. This study was registered as a clinical trial at clinicaltrials.gov under the number NCT02434588.

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.

Diffusion-Weighted-Imaging infarct volume measurement tools show discrepancies leading to diverging thrombectomy decisions.

BACKGROUND AND PURPOSE: Recent clinical trials demonstrated the benefit of thrombectomy beyond 6h based on the automated measurement of infarct volume exclusively with the RAPID software. We aimed to compare eight tools commonly used for the measurement of infarct volume and see whether they would lead to similar thrombectomy decisions based on the Diffusion-weighted-imaging or computerized-tomography-perfusion Assessment with clinical mismatch in the triage of Wake-up and late-presenting strokes undergoing Neurointervention with Trevo (DAWN) trial imaging inclusion criteria. MATERIALS AND METHODS: The diffusion-weighted-imaging (DWI) infarct volume of 36 patients was measured with 3 automated tools (including RAPID) and 5 non-automated tools. The agreement for the measurements of DWI infarct volume and the resulting thrombectomy decisions were assessed with intraclass correlation coefficient (ICC) and Fleiss' Kappa (K) statistics. RESULTS: The correlation for the measurement of DWI infarct volume between all 9 tools was excellent (ICC>0.8). After dichotomization, agreement was substantial for any of the cut-points used in DAWN trial. Discrepancies involving at least one of the tools for thrombectomy decisions based on DAWN criteria occurred in one third of cases. Compared with RAPID, the use of any other tool for treatment decision based on DAWN criteria would have led to contradictory decisions in 6% to 19% of cases. CONCLUSION: There are several currently available tools for the measurement of DWI infarct volume with excellent correlation. Despite the high agreement demonstrated in our study, frequent discrepancies between measurements in some dichotomized configurations led to frequent diverging thrombectomy decisions when applying DAWN criteria.

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.

Teaching robotic rectal cancer surgery at your workplace: does the presence of visiting surgeons in the operating room have a detrimental effect on outcomes?

BACKGROUND: Surgery demonstration (SD) is considered to be a mainstay of surgical education, but controversy exists concerning the patient's safety. Indeed, the presence of visiting surgeons is a source of distraction and may have an impact on surgeon's performance. This study's objective was to evaluate possible differences in outcomes between robotic sphincter-saving rectal cancer surgery (RRCS) performed during routine surgical practice versus in the presence of visiting surgeons in the operating room (OR) with direct access to the surgeon. METHODS: Retrospective case-matched studies were conducted from a prospectively collected database. 114 patients (38 with the presence of visiting surgeons) who underwent RRCS between January 2013 and September 2018 were included. Patients were matched in a 1:2 basis after propensity score analysis using five criteria: gender, body mass index, preoperative chemoradiation, type of mesorectum excision, and synchronous liver metastasis. RESULTS: There was no difference between the two groups with regard to mean operating time, estimated blood loss, conversion, and hospital stay. Also, overall (44% vs. 40%; P = 0.6), major morbidity (26% vs. 19%; P = 0.5), and unplanned reoperation (17% vs. 15%; P = 1.0) rates were not statistically different. No difference was noted with regard to the quality of mesorectum excision, or positive rate of circumferential and distal longitudinal resection margins. The mean number of harvested lymph nodes (17 vs. 14.5; P = 0.04) was lower in the SD group and the number of patients with < 12 harvested lymph nodes (31% vs. 16%; P = 0.09) was greater after SD although it did not reach statistical significance. No differences were observed in disease-free or overall survival. CONCLUSIONS: The presence of visiting surgeons in the OR seems not to interfere in the quality of rectal resection and does not compromise patient's short-term outcome and survival. However, mild differences in the extent of lymphadenectomy were observed and the surgeons performing SD may be aware of this.

Minimally invasive versus open right hepatectomy: comparative study with propensity score matching analysis.

BACKGROUND: Minimally invasive liver resections (MILRs) have been increasingly performed in recent years. However, the majority of MILRs are actually minor or limited resections of peripheral lesions. Due to the technical complexity major hepatectomies remain challenging for minimally invasive surgery. The aim of this study was to compare the short and long-term outcomes of patients undergoing minimally invasive right hepatectomies (MIRHs) with contemporary patients undergoing open right hepatectomies (ORHs) METHODS: Consecutive patients submitted to anatomic right hepatectomies between January 2013 and December 2018 in two tertiary referral centers were studied. Study groups were compared on an intention-to-treat basis after propensity score matching (PSM). Overall survival (OS) analyses were performed for the entire cohort and specific etiologies subgroups RESULTS: During study period 178 right hepatectomies were performed. After matching, 37 patients were included in MIRH group and 60 in ORH group. The groups were homogenous for all baseline characteristics. MIRHs had significant lower blood loss (400 ml vs. 500 ml, P = 0.01), lower rate of minor complications (13.5% vs. 35%, P = 0.03) and larger resection margins (10 mm vs. 5 mm, P = 0.03) when compared to ORHs. Additionally, a non-significant decrease in hospital stay (ORH 9 days vs. MIRH 7 days, P = 0.09) was observed. No differences regarding the use of Pringle's maneuver, operative time, overall morbidity or perioperative mortality were observed. OS was similar between the groups (P = 0.13). Similarly, no difference in OS was found in subgroups of patients with primary liver tumors (P = 0.09) and liver metastasis (P = 0.80). CONCLUSIONS: MIRHs are feasible and safe in experienced hands. Minimally invasive approach was associated with less blood loss, a significant reduction in minor perioperative complications, and did not negatively affect long-term outcomes.

Early Detection of Anal High-Grade Squamous Intraepithelial Lesion: Do We Have an Impact on Progression to Invasive Anal Carcinoma?

OBJECTIVE: Anal high-grade squamous intraepithelial lesion (HSIL) may precede invasive cancer and can be detected clinically or during high-resolution anoscopy (HRA). The aims of this study were to compare the characteristics of HSIL discovered by HRA or in a surgical specimen without clinically visible lesion when diagnosed versus macroscopic HSIL when first diagnosed and then to compare their progression to invasive cancer. PATIENTS AND METHODS: Clinical records of all patients with at least one HSIL lesion confirmed by histology and evaluated by HRA in a single center between September 1, 2009, and April 30, 2017, were retrospectively reviewed. The center's histological anal cancer data base was questioned in December 2017 to identify all cases. RESULTS: During a median (interquartile range) follow-up of 19.1 (5.6-40.2) months, 12 (2.9%) anal cancers were diagnosed in patients with a diagnosis of HSIL. Period of time between the first diagnosis of anal lesion and the cancer was 28.8 months (interquartile range = 15.4-65.6), and 11 (92%) of 12 were diagnosed as superficially invasive squamous cell carcinoma or T1N0M0. The rate of progression to anal cancer differed significantly between patients with macroscopic HSIL at diagnosis (5.4%) and patients with microscopic HSIL diagnosed during HRA (0.9%) (p = .01). CONCLUSIONS: Patients with macroscopic histologically proven HSIL at first diagnosis of anal intraepithelial lesion have a significantly higher risk of anal cancer compared with patients with microscopic lesions diagnosed during HRA, but the duration between the first diagnosis of HSIL and cancer does not differ between the 2 groups.

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.

Predictors of Parenchymal Hematoma After Mechanical Thrombectomy: A Multicenter Study

Background and Purpose: Parenchymal hematoma (PH) is a rare but dreadful complication of acute ischemic stroke with unclear underlying mechanisms. We aimed to study the incidence and predictors of PH after mechanical thrombectomy. Methods: Data from a prospective observational multicenter registry was screened to identify acute ischemic stroke patients with an anterior circulation large vessel occlusion who underwent mechanical thrombectomy. Clinical, imaging, and procedural characteristics were used for the analysis, including brain imaging systematically performed at 24 hours. PH occurrence was assessed according to ECASS (European Collaborative Acute Stroke Study) criteria. Univariate and multivariable analyses were performed to identify predictors of PH. Results: A total of 1316 patients were included in the study. PH occurred in 153 out of 1316 patients (11.6%) and was associated with a lower rate of favorable outcome and increased mortality. On multivariable analysis, age (per 1 year increase, odds ratio [OR], 1.01; 95% CI, 1.00­1.03; P=0.05), current smoking (OR, 2.02; 95% CI, 1.32­3.09; P<0.01), admission Alberta Stroke Program Early CT Score (per a decrease of 1 point, OR, 1.70; 95% CI, 1.18­2.44; P<0.01), general anesthesia (OR, 1.98; 95% CI, 1.36­2.90; P<0.001), angiographic poor collaterals (OR, 2.13; 95% CI, 1.36­3.33; P<0.001) and embolization in new territory (OR, 2.94; 95% CI, 1.70­5.10; P<0.001) were identified as independent predictors of PH. Conclusions: PH occurred at a rate of 11.6% after mechanical thrombectomy, with high morbidity and mortality. Our study identified clinical, radiological, and procedural predictors of PH occurrence that can serve as the focus of future periprocedural management studies with the aim of reducing its occurrence.

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.

Proposed achievable levels of dose and impact of dose-reduction systems for thrombectomy in acute ischemic stroke: an international, multicentric, retrospective study in 1096 patients.

BACKGROUND: International dose reference levels are lacking for mechanical thrombectomy in acute ischemic stroke patients with large vessel occlusions. We studied whether radiation dose-reduction systems (RDS) could effectively reduce exposure and propose achievable levels. MATERIALS AND METHODS: We retrospectively included consecutive patients treated with thrombectomy on a biplane angiography system (BP) in five international, high-volume centers between January 2014 and May 2017. Institutional Review Board approvals were obtained. Technical, procedural, and clinical characteristics were assessed. Efficacy, safety, radiation dose, and contrast load were compared between angiography systems with and without RDS. Multivariate analyses were adjusted according to Bonferroni's correction. Proposed international achievable cutoff levels were set at the 75th percentile. RESULTS: Out of the 1096 thrombectomized patients, 520 (47%) were treated on a BP equipped with RDS. After multivariate analysis, RDS significantly reduced dose-area product (DAP) (91 vs 140 Gy cm2, relative effect 0.74 (CI 0.66; 0.83), 35% decrease, p < 0.001) and air kerma (0.46 vs 0.97 Gy, relative effect 0.63 (CI 0.56; 0.71), 53% decrease, p < 0.001) with 75th percentile levels of 148 Gy cm2 and 0.73 Gy, respectively. There was no difference in contrast load, rates of successful recanalization, complications, or clinical outcome. CONCLUSION: Radiation dose-reduction systems can reduce DAP and air kerma by a third and a half, respectively, without affecting thrombectomy efficacy or safety. The respective thresholds of 148 Gy cm2 and 0.73 Gy represent achievable levels that may serve to optimize current and future radiation exposure in the setting of acute ischemic stroke treatment. As technology evolves, we expect these values to decrease. KEY POINTS: • Internationally validated achievable levels may help caregivers and health authorities better assess and reduce radiation exposure of both ischemic stroke patients and treating staff during thrombectomy procedures. • Radiation dose-reduction systems can reduce DAP and air kerma by a third and a half, respectively, without affecting thrombectomy efficacy or safety in the setting of acute ischemic stroke due to large vessel occlusion.

DWI-ASPECTS (Diffusion-Weighted Imaging-Alberta Stroke Program Early Computed Tomography Scores) and DWI-FLAIR (Diffusion-Weighted Imaging-Fluid Attenuated Inversion Recovery) Mismatch in Thrombectomy Candidates: An Intrarater and Interrater Agreement Study.

BACKGROUND AND PURPOSE: We aimed to study the intrarater and interrater agreement of clinicians attributing DWI-ASPECTS (Diffusion-Weighted Imaging-Alberta Stroke Program Early Computed Tomography Scores) and DWI-FLAIR (Diffusion-Weighted Imaging-Fluid Attenuated Inversion Recovery) mismatch in patients with acute ischemic stroke referred for mechanical thrombectomy. METHODS: Eighteen raters independently scored anonymized magnetic resonance imaging scans of 30 participants from a multicentre thrombectomy trial, in 2 different reading sessions. Agreement was measured using Fleiss κ and Cohen κ statistics. RESULTS: Interrater agreement for DWI-ASPECTS was slight (κ=0.17 [0.14-0.21]). Four raters (22.2%) had a substantial (or higher) intrarater agreement. Dichotomization of the DWI-ASPECTS (0-5 versus 6-10 or 0-6 versus 7-10) increased the interrater agreement to a substantial level (κ=0.62 [0.48-0.75] and 0.68 [0.55-0.79], respectively) and more raters reached a substantial (or higher) intrarater agreement (17/18 raters [94.4%]). Interrater agreement for DWI-FLAIR mismatch was moderate (κ=0.43 [0.33-0.57]); 11 raters (61.1%) reached a substantial (or higher) intrarater agreement. CONCLUSIONS: Agreement between clinicians assessing DWI-ASPECTS and DWI-FLAIR mismatch may not be sufficient to make repeatable clinical decisions in mechanical thrombectomy. The dichotomization of the DWI-ASPECTS (0-5 versus 0-6 or 0-6 versus 7-10) improved interrater and intrarater agreement, however, its relevance for patients selection for mechanical thrombectomy needs to be validated in a randomized trial.

Assessment of axial rotation movement in cervical dystonia using cone-beam computed tomography.

BACKGROUND: Cervical dystonia is a neurological disorder characterized by involuntary muscle contractions and abnormal postures of the head and neck. Botulinum neurotoxin injection is the first-line treatment. Imaging determination of the cervical segments involved (lower or upper according to the torticollis-torticaput [COL-CAP] Classification) is an aid in determining the muscles to be injected. We aimed to clarify the impact of dystonia on posture and rotational movement of cervical vertebrae in the transverse plane. METHODS: A comparative study was conducted in a movement disorders department. Ten people with cervical dystonia and 10 matched healthy subjects (without cervical dystonia) were recruited. 3-D images of posture and cervical range of motion in axial rotation in the sitting position were recorded by using a cone-beam CT scanner. Range of rotational motion of the upper cervical spine from the occipital bone to fourth cervical vertebra was measured and compared between the two groups. FINDINGS: The head posture analysis showed that the total cervical spine position was more significantly distant from the neutral position for people with dystonia than healthy subjects (p = 0.007). The rotational range of motion of the cervical spine was significantly lower in cervical dystonia participants than in healthy subjects for the total (p = 0.026) and for upper cervical spine (p = 0.004). INTERPRETATION: We demonstrated, by means of cone-beam CT, that the disorganization of movements due to cervical dystonia affected the upper cervical spine and mostly the atlantoaxial joint. The involvement of rotator muscles at this cervical level should be considered more in treatments.

Generalization of ocular myasthenia gravis 10 years after onset.

BACKGROUND: Generalization of ocular myasthenia gravis (OMG) represents a pejorative evolution, and no validated generalization-prevention strategy exists. The study aimed to determine the percentage of patients with OMG generalization and identify factors predictive of it to establish a prediction score. METHODS: This retrospective, observational study included 151 patients diagnosed with OMG after an initial work-up in our institution. The outcome measure was time to MG generalization. The explanatory variables were age at onset (> 55 years), sex, first-year anti-acetylcholine-receptor antibody-positivity, repetitive nerve stimulation showing electromyogram decrement and corticosteroid use. Kaplan-Meier estimations of the probability of risk of generalization, and descriptive and multivariate Cox model analyses were computed. A nomogram combining explanatory variables was used to establish a score to predict the probability of OMG generalization. RESULTS: Among 183 patients' charts identified, 151 had confirmed OMG. Their median follow-up was 5.7 years. Estimations (95% CI) of OMG-generalization risk at 1, 3 and 10 years post-symptom onset, respectively, were: 13.0% (7.3-18.2), 25.1% (17.5-32.0) and 37.8% (27.2-45.2). The p-value-based multivariate analysis associated generalization with female sex, electromyogram decrement and first-year anti-acetylcholine-receptor antibody positivity, and Akaike information criterion-based analysis retained those three parameters and corticosteroid use. A nomogram was built and validated with an optimism-corrected C-statistic of 0.68, and calibration plots showed good fit. CONCLUSIONS: Our population's percentage of OMG generalization is in line with recent publications. Using the identified prognostic factors, the nomogram provided a score to predict the probable risk of generalization in our cohort.

Diagnostic accuracy of Quantitative Colour Doppler Flow imaging in distinguishing Persistent Fetal Vasculature from Retinal Detachment.

PURPOSE: Distinguishing posterior persistent fetal vasculature (PFV) from retinal detachment (RD) may be very challenging clinically and ultrasonographically, as they share common morphological features. However, it is crucial, considering their substantially distinct management and treatment. We aimed to assess the relevance of quantitative colour Doppler flow imaging to distinguish PFV from RD in children. METHODS: This retrospective bi-centre study included 66 children (30 females and 36 males, mean age: 244 ± 257 days) with a clinically suspected diagnosis of RD or posterior PFV. All children underwent systematic and standardized conventional ultrasonography and colour Doppler flow imaging under general anaesthesia with a qualitative and quantitative analysis of the retrolental tissue's vascularization. Peak systolic velocity, end-diastolic velocity and resistive index were recorded for analysis. Whenever available, surgical findings were deemed gold standard for diagnosis. A Mann-Whitney U-test was used to compare quantitative colour Doppler flow imaging data. RESULTS: Peak systolic velocity and end-diastolic velocity were significantly lower in children with PFV versus RD: 2.7 (IQR: 0.5) versus 5.1 (IQR: 2.8), p < 0.001, and 0.0 (IQR: 0.0) versus 2.0 (IQR: 1.2), p < 0.001, respectively. Resistive index was significantly higher in children with PFV versus RD: 1 (IQR: 0) versus 0.6 (IQR: 0.1), p < 0.001. Area under curves (AUCs) were of 0.94, 0.99 and 1, respectively. No differences between PFV and RD were observed on structural ultrasound or qualitative analysis of colour Doppler. CONCLUSION: Quantitative colour Doppler flow imaging has an excellent accuracy in distinguishing PFV from RD in children. It may help to improve management and treatment.