Varicella Zoster Associated Vasculopathy and Retinitis with Natalizumab Use in Multiple Sclerosis.

Natalizumab (Tysabri®, NTZ) is a monoclonal autoantibody approved for treatment of relapsing-remitting multiple sclerosis. NTZ inhibits leukocyte migration across the blood-brain barrier, preventing autoreactive cells from inciting an inflammatory immune response. This immunosuppression is highly efficacious in attenuating the risk of relapse of disease, but has been associated with opportunistic central nervous system (CNS) infections, most notably progressive multifocal leukoencephalopathy. Varicella-zoster and herpes simplex viruses have also been associated with NTZ, inciting a spectrum of disease, including encephalitis, meningitis, and acute retinal necrosis. While rare, these infections can result in devastating outcomes even when promptly identified and treated.   We present a case of combined CNS varicella zoster vasculitis and acute retinal necrosis in a 57-year-old woman maintained on monthly Natalizumab therapy, who presented with headache and visual field deficits.

Use of Large Language Models to Predict Neuroimaging.

PURPOSE: Large language models (LLMs) have demonstrated a level of competency within the medical field. The aim of this study was to explore the ability of LLMs to predict the best neuroradiologic imaging modality given specific clinical presentations. In addition, the authors seek to determine if LLMs can outperform an experienced neuroradiologist in this regard. METHODS: ChatGPT and Glass AI, a health care-based LLM by Glass Health, were used. ChatGPT was prompted to rank the three best neuroimaging modalities while taking the best responses from Glass AI and the neuroradiologist. The responses were compared with the ACR Appropriateness Criteria for 147 conditions. Clinical scenarios were passed into each LLM twice to account for stochasticity. Each output was scored out of 3 on the basis of the criteria. Partial scores were given for nonspecific answers. RESULTS: ChatGPT and Glass AI scored 1.75 and 1.83, respectively, with no statistically significant difference. The neuroradiologist scored 2.20, significantly outperforming both LLMs. ChatGPT was also found to be the more inconsistent of the two LLMs, with the score difference between both outputs being statistically significant. Additionally, scores between different ranks output by ChatGPT were statistically significant. CONCLUSIONS: LLMs perform well in selecting appropriate neuroradiologic imaging procedures when prompted with specific clinical scenarios. ChatGPT performed the same as Glass AI, suggesting that with medical text training, ChatGPT could significantly improve its function in this application. LLMs did not outperform an experienced neuroradiologist, indicating the need for continued improvement in the medical context.

The evaluation of the swallow tail sign in patients with parkinsonism and gait disorders.

BACKGROUND: Swallow tail sign (STS), which represents nigrosome-1 in the substantia nigra on 3 Tesla (T) susceptibility-weighted imaging (SWI), has attracted attention as a promising magnetic resonance imaging (MRI) biomarker for idiopathic Parkinson's disease (iPD). Some reports have shown high sensitivity and specificity-both above 94%-for distinguishing iPD from healthy controls. However, abnormal STS has been observed in many neurodegenerative parkinsonisms and even in multiple sclerosis. METHODS: All patients with parkinsonism who had 3 T MRI were included in a retrospective chart review from a single movement disorders clinic. All subjects were evaluated by a single movement disorder specialist, using Movement Disorders Society diagnostic criteria and American Academy of Neurology consensus guidelines for diagnoses. All MRIs were interpreted by a single neuroradiologist who was blinded to the diagnosis. RESULTS: Twenty patients were included in the study. Twelve had abnormal STS: iPD (n = 2), probable multiple system atrophy (n = 3), vascular parkinsonism (n = 1), psychogenic gait disorder (n = 1), neuroleptic parkinsonism (n = 2), cervical dystonia (n = 1), static encephalopathy (n = 1) and gait disorder of unknown etiology (n = 1). Eight had normal STS: iPD (n = 1), probable progressive supranuclear palsy (n = 1), vascular parkinsonism (n = 2), transient parkinsonism of unknown etiology (n = 2), valproic acid induced parkinsonism (n = 1), and essential tremor with parkinsonism (n = 1). 123I-Ioflupane SPECT dopamine transporter (DaT) scan results were available on seven subjects; four subjects had incongruency between DaT and MRI. CONCLUSION: Our results suggest that the abnormal STS is not, in isolation, a reliable biomarker of idiopathic Parkinson's disease.

Long-term outcomes of anterior cruciate ligament reconstruction surgery: 2020 OREF clinical research award paper.

ACL injuries place the knee at risk for post-traumatic osteoarthritis (PTOA) despite surgical anterior cruciate ligament (ACL) reconstruction. One parameter thought to affect PTOA risk is the initial graft tension. This randomized controlled trial (RCT) was designed to compare outcomes between two graft tensioning protocols that bracket the range commonly used. At 7 years postsurgery, we determined that most outcomes between the two tension groups were not significantly different, that they were inferior to an uninjured matched control group, and that PTOA was progressing in both groups relative to controls. The trial database was also leveraged to gain insight into mechanisms of PTOA following ACL injury. We determined that the inflammatory response at the time of injury undermines one of the joint's lubricating mechanisms. We learned that patients continue to protect their surgical knee 5 years postinjury compared to controls during a jump-pivot activity. We also established that presurgical knee function and mental health were correlated with symptomatic PTOA at 7 years, that there were specific anatomical factors associated with poor outcomes, and that there were no changes in outcomes due to tunnel widening in patients receiving hamstring tendon autografts. We also validated a magnetic resonance imaging technique to noninvasively assess graft strength. In conclusion, the RCT determined that initial graft tensioning does not have a major influence on 7-year outcomes. Therefore, surgeons can reconstruct the ACL using a graft tensioning protocol that is within the window of the two graft tensioning techniques evaluated in this RCT.

Posterior reversible encephalopathy syndrome (PRES): Another imaging manifestation of COVID-19.

Neuroimaging manifestations of COVID-19 are being reported with increasing frequency with recent reports of associated atypical leukoencephalopathies. We add to this literature by describing a COVID-19 + patient who demonstrated imaging findings typical for posterior reversible encephalopathy syndrome (PRES). The inflammatory syndrome associated with novel corona virus infection has shown markedly increased levels of cytokines and inflammatory markers. This has also been described in a proposed mechanism for PRES, where elevated inflammatory markers result in endothelial injury causing interstitial fluid extravasation typical of PRES. We expect that other cases of PRES will be observed in this population given the scope of the Covid-19 pandemic.

Rethinking Thrombolysis in Cerebral Infarction 2b: Which Thrombolysis in Cerebral Infarction Scales Best Define Near Complete Recanalization in the Modern Thrombectomy Era?

BACKGROUND AND PURPOSE: Within the thrombolysis in cerebral infarction (TICI) classification, TICI 2b has been historically considered successful recanalization. Recent studies have suggested that TICI 3 and a proposed TICI 2c should be separately reported from TICI 2b, in both the original (>66% reperfusion) and modified (>50% reperfusion) definitions, because of differences in clinical outcomes with greater reperfusion. The purpose of this study was to evaluate differences in early neurological improvement and independence at 90 days using the original TICI, modified TICI, and modified TICI with 2c scales. METHODS: A retrospective review of 129 consecutive patients with middle cerebral artery, M1 segment or intracranial internal carotid artery occlusions. Patient angiograms were graded by 2 experienced readers by percentage recanalization. This was then categorized into original TICI, modified TICI (mTICI), and mTICI with TICI 2c (mTICI 2c) grading scales. Comparison of baseline demographics, early neurological improvement, and independence at 90 days was performed. RESULTS: A significant difference in early neurological improvement was observed between 2b and 3 (P=0.032), as well as between 2b and 2c (P=0.028) under the mTICI 2c grading scale. Similarly, a significant difference in functional independence was observed between 2b and 3 (P=0.037), as well as between 2b and 2c (P=0.047) under the mTICI 2c scale. The difference in early neurological improvement or functional independence between 2b and 3 for the original TICI and mTICI scales was not significant. When combining the 2c and 3 groups under the mTICI 2c scale, there were significant differences between 2b and 2c/3 in regards to both early neurological improvement (P=0.011) and independence (P=0.018). CONCLUSIONS: Using a TICI grading system that includes an additional category beyond TICI 2b allows for refined prediction of early neurological improvement and functional independence.

Effect of Matching or Overconstraining Knee Laxity During Anterior Cruciate Ligament Reconstruction on Knee Osteoarthritis and Clinical Outcomes: A Randomized Controlled Trial With 84-Month Follow-up.

BACKGROUND: The "initial graft tension" applied at the time of graft fixation during anterior cruciate ligament (ACL) reconstruction surgery modulates joint contact mechanics, which in turn may promote posttraumatic osteoarthritis (OA). PURPOSE/HYPOTHESES: The study objectives were to compare clinical, functional, patient-reported, and OA imaging outcomes between 2 different initial laxity-based graft tension cohorts and a matched uninjured control group as well as to evaluate the effects of laxity-based graft tension on OA development at 84-month follow-up. The 2 laxity-based tension protocols were (1) to restore normal anteroposterior (AP) laxity at the time of surgery relative to the contralateral uninjured knee (low-tension group) or (2) to overconstrain AP laxity by 2 mm relative to the contralateral uninjured knee (high-tension group). The hypotheses were that (1) the high-tension group would have improved outcomes and decreased OA compared with the low-tension group after 84 months, and (2) the outcomes for the high-tension group would be equivalent to those for an age-, sex-, race-, and activity-matched group of control participants with uninjured knees. STUDY DESIGN: Randomized controlled trial; Level of evidence, 1. METHODS: Patients had their ACLs reconstructed with either a bone-patellar tendon-bone or 4-stranded hamstring autograft, and outcomes were compared with a matched control group. Outcomes were evaluated preoperatively and at 60 and 84 months postoperatively and included clinical (KT-1000 arthrometer AP laxity measurement and International Knee Documentation Committee [IKDC] examination score), functional (1-legged hop for distance and knee extensor torque), patient-reported (Knee injury and Osteoarthritis Outcome Score [KOOS], Short Form-36 [SF-36], and patient satisfaction survey), and OA imaging (measurement of joint space width [JSW], Osteoarthritis Research Society International [OARSI] radiographic score, and Whole-Organ Magnetic Resonance Imaging Score [WORMS]) components. Repeated-measures analyses of variance were used to evaluate differences in outcomes between the treatment groups and the control group. RESULTS: There were significant differences between the 2 tension groups in 1 of 5 KOOS subscales (sports and recreation; P = .04) and 2 of 8 SF-36 subscales (vitality, mental health; P < .04) at 84 and 60 months, respectively. Both tension groups scored significantly worse than the control group in the IKDC examination (P < .001), 1-legged hop (P ≤ .017), KOOS quality of life and symptoms subscales (P < .03), and OARSI radiographic score (P ≤ .02) at 84 months. The low-tension group performed significantly worse than the control group on the KOOS pain subscale (P = .03), SF-36 general health and social functioning (P < .04), OARSI radiographic score (P < .001), and WORMS (P = .001), while the high-tension group had statistically different results than the control group in AP knee laxity (P < .001), radiographic JSW (P = .003), and OARSI radiographic score (P = .02) as well as significantly more subsequent knee injuries (P = .02) at 84 months. CONCLUSION: The results do not support the hypotheses that the high-tension group would have improved outcomes when compared with the low-tension group after 84 months of healing or that the outcomes for the high-tension group would be equivalent to those for the matched control group. While there were minor differences in patient-reported outcomes between the 2 laxity-based tension groups, all other outcomes were similar. REGISTRATION: NCT00434837.

In utero diagnosis of caudal regression syndrome.

We present a case of caudal regression syndrome (CRS), a relatively uncommon defect of the lower spine accompanied by a wide range of developmental abnormalities. CRS is closely associated with pregestational diabetes and is nearly 200 times more prevalent in infants of diabetic mothers (1, 2). We report a case of prenatally suspected CRS in a fetus of a nondiabetic mother and discuss how the initial neurological abnormalities found on imaging correlate with the postnatal clinical deficits.

MRI volume and signal intensity of ACL graft predict clinical, functional, and patient-oriented outcome measures after ACL reconstruction.

BACKGROUND: Clinical, functional, and patient-oriented outcomes are commonly used to evaluate the efficacy of treatments after anterior cruciate ligament (ACL) injury; however, these evaluation techniques do not directly measure the biomechanical changes that occur with healing. PURPOSE: To determine if the magnetic resonance (MR) image-derived parameters of graft volume and signal intensity (SI), which have been used to predict the biomechanical (ie, structural) properties of the graft in animal models, correlate with commonly used clinical (anteroposterior [AP] knee laxity), functional (1-legged hop), and patient-oriented outcome measures (Knee Injury and Osteoarthritis Outcome Score [KOOS]) in patients 3 and 5 years after ACL reconstruction. STUDY DESIGN: Cohort study (diagnosis); Level of evidence, 3. METHODS: Based on a subset of participants enrolled in an ongoing ACL reconstruction clinical trial, AP knee laxity, 1-legged hop test, and KOOS were assessed at 3- and 5-year follow-up. Three-dimensional, T1-weighted MR images were collected at each visit. Both the volume and median SI of the healing graft were determined and used as predictors in a multiple regression linear model to predict the traditional outcome measures. RESULTS: Graft volume combined with median SI in a multiple linear regression model predicted 1-legged hop test at both the 3- and 5-year follow-up visits (R(2) = 0.40, P = .008 and R(2) = 0.62, P = .003, respectively). Similar results were found at the 5-year follow-up for the KOOS quality of life (R(2) = 0.49, P = .012), sport/function (R(2) = 0.37, P = .048), pain (R(2) = 0.46, P = .017), and symptoms (R(2) = 0.45, P = .021) subscores, although these variables were not significant at 3 years. The multiple linear regression model for AP knee laxity at 5-year follow-up approached significance (R(2) = 0.36, P = .088). CONCLUSION: The MR parameters (volume and median SI) used to predict ex vivo biomechanical properties of the graft in an animal model have the ability to predict clinical or in vivo outcome measures in patients at 3- and 5-year follow-up. CLINICAL RELEVANCE: Results from this study may enhance clinical evaluation of graft health by relating the MR parameters of volume and median SI to traditional outcome measures and could potentially aid researchers in determining the appropriate timing for athletes to return to sport.

The effect of initial graft tension after anterior cruciate ligament reconstruction: a randomized clinical trial with 36-month follow-up.

BACKGROUND: The initial graft tension applied at the time of anterior cruciate ligament (ACL) reconstruction alters joint contact and may influence cartilage health. The objective was to compare outcomes between 2 commonly used "laxity-based" initial graft tension protocols. HYPOTHESES: (1) The high-tension group would have less knee laxity, improved clinical and patient-oriented outcomes, and less cartilage damage than would the low-tension group after 36 months of healing. (2) The outcomes of the high-tension group would be equivalent to those of a matched control group. STUDY DESIGN: Randomized controlled trial; Level of evidence, 1. METHODS: Ninety patients with isolated unilateral ACL injuries were randomized to undergo ACL reconstruction using 1 of 2 initial graft tension protocols: (1) autografts tensioned to restore normal anterior-posterior (AP) laxity at the time of surgery (ie, low tension; n = 46) and (2) autografts tensioned to overconstrain AP laxity by 2 mm (ie, high tension; n = 44). Sixty matched healthy patients formed the control group. Outcomes were assessed preoperatively, intraoperatively, and at 6, 12, and 36 months after surgery. RESULTS: No significant differences were found between the 2 initial graft tension protocols for any of the outcome measures at 36 months. However, there were differences when comparing the 2 treatment groups to the control group. On average, AP laxity was 2 mm greater in the ACL-reconstructed groups than in the control group (P < .007). International Knee Documentation Committee (IKDC) knee evaluation scores, peak isokinetic knee extension torques, and 4 of 5 Knee Osteoarthritis Outcome Scores (KOOS) were significantly worse than the control group (P < .001, P < .027, and P < .05, respectively). Short Form-36 Health Survey (SF-36) scores and reinjury rates were similar between groups at 36 months. Although there were significant changes in radiography and magnetic resonance imaging present in the ACL-reconstructed knees of both treatment groups, the magnitude was relatively small and likely clinically insignificant at 36 months. CONCLUSION: Both laxity-based initial graft tension protocols produced similar outcomes without fully restoring joint function or patient-oriented outcomes (KOOS) when compared with the control group. There was minimal evidence of cartilage damage 36 months after surgery.

Quantitative magnetic resonance imaging detects changes in meniscal volume in vivo after partial meniscectomy.

BACKGROUND: Quantifying changes in meniscal volume in vivo before and after partial meniscectomy (PM) could help elucidate the mechanisms involved in osteoarthritis development after meniscal injury and its surgical treatment. Purpose/ HYPOTHESIS: To determine whether quantitative magnetic resonance imaging (qMRI) can detect the immediate reduction in meniscal volume created by PM, while ruling out changes in unresected structures. We hypothesized that qMRI would be reliable for determining meniscal volume within the repeated images of unresected menisci. Additionally, we expected no significant difference in volume between the uninjured menisci of the injured knees and the same menisci of the uninjured knees. STUDY DESIGN: Cohort study (Diagnosis); Level of evidence, 2. METHODS: Ten subjects with meniscal tears were evaluated with 3-T MRI before and after arthroscopic PM. Manual segmentation was used to create models of the menisci and to determine the preoperative and postoperative meniscal volumes for each subject. The responsiveness and reliability of qMRI for determining meniscal volume in vivo were evaluated using these measurements. We expected a decrease in volume of the resected menisci, but not in the uninjured menisci, after surgery. RESULTS: The mean preoperative volume of the injured menisci was significantly greater than the mean postoperative volume (2896 +/- 277 vs 2480 +/- 277 mm(3); P = .000). There was no significant difference between the mean preoperative and postoperative volumes of the uninjured menisci (2687 +/- 256 vs 2694 +/- 256 mm(3); P = 1.000). CONCLUSION: Manual segmentation demonstrated a significant reduction in the volume of the surgically resected menisci after PM, but no significant change in the volume of unresected meniscal tissue, indicating that the manual segmentation method is responsive. CLINICAL RELEVANCE: This approach offers a novel, reliable method to study the relationship between the volume of meniscal tissue removed during PM and subsequent patient outcomes during long-term clinical studies.

Acute retrobulbar optic neuritis and macular detachment associated with morning glory optic disc anomaly.

A 31-year-old woman with morning glory optic disc anomaly (MGDA) developed acute retrobulbar optic neuritis and a bullous macular detachment. MRI demonstrated truncation of the perineural space of the affected optic nerve as well as focal optic nerve enhancement. Optical coherence tomography (OCT) showed retinoschisis associated with the macular detachment. The MRI and OCT findings support the vitreous as the source of the subretinal fluid. This is the first reported case of optic neuritis in MGDA.

Diffusion-weighted MRI of peripheral zone prostate cancer: comparison of tumor apparent diffusion coefficient with Gleason score and percentage of tumor on core biopsy.

OBJECTIVE: The objective of our study was to determine the relationship between the apparent diffusion coefficient (ADC) value on diffusion-weighted imaging (DWI) and Gleason score of prostate cancer and percentage of tumor involvement on prostate core biopsy. MATERIALS AND METHODS: We performed a retrospective study of 57 patients with biopsy-proven prostate cancer who underwent endorectal MRI with DWI between July 2007 and March 2008. Regions of interest (ROIs) were drawn on ADC maps at sites of visible tumor on DW images and ADC maps. A hierarchic mixed linear model was used to compare the ADC value of prostate cancer with the Gleason score and the percentage of tumor on core biopsy. RESULTS: Eighty-one sites of biopsy-proven prostate cancer were visible on DW images and ADC maps. The least-squares mean ADC for disease with a Gleason score of 6 was 0.860 x 10(-3) mm(2)/s (standard error of the mean [SEM], 0.036); Gleason score of 7, 0.702 x 10(-3) mm(2)/s (SEM, 0.030); Gleason score of 8, 0.672 x 10(-3) mm(2)/s (SEM, 0.057); and Gleason score of 9, 0.686 x 10(-3) mm(2)/s (SEM, 0.067). Differences between the mean ADC values for a prostate tumor with a Gleason score of 6 and one with a Gleason score of 7 (p = 0.0096) and for a prostate tumor with a Gleason score of 6 and one with a Gleason score of 8 (p = 0.0460) were significant. Comparison between the ADC and percentage of tumor on core biopsy showed a mean ADC decrease of 0.006 (range, 0.004-0.008 x 10(-3) mm(2)/s) for every 1% increase in tumor in the core biopsy specimen. CONCLUSION: DWI may help differentiate between low-risk (Gleason score, 6) and intermediate-risk (Gleason score, 7) prostate cancer and between low-risk (Gleason score, 6) and high-risk (Gleason score > 7) prostate cancer. There is an inverse relationship between the ADC and the percentage of tumor involvement on prostate core biopsies.

Assessment of bone perfusion with contrast-enhanced magnetic resonance imaging.

Osteoarthritis and avascular necrosis are common clinical entities with unknown origins. Recently, vascular changes were implicated in the pathogenesis of both conditions. This article discusses the use of novel noninvasive imaging techniques as a means of assessing bone perfusion and quantifying differences seen in osteoarthritis and avascular necrosis. Review of our human data suggests that the MRI contrast dye is retained for longer periods of time, suggesting decreased perfusion out of regions of osteoarthritis and avascular necrosis. Use of such a noninvasive measure of assessing bone perfusion could be useful in the diagnosis, prevention, and treatment of not only osteoarthritis and avascular necrosis but also other entities that affect the musculoskeletal system.

Imaging signs of posterior glenohumeral instability.

OBJECTIVE: The purpose of this article is to review mechanisms of injury leading to posterior glenohumeral instability and the correlated imaging findings on CT and MRI. CONCLUSION: In patients with suspected posterior glenohumeral instability, imaging of the affected shoulder can show abnormalities of the bone, labrum, and joint capsule. Accurate detection and characterization of these lesions aid in both diagnosis and management.