Does Gadolinium Deposition Lead to Metabolite Alteration in the Dentate Nucleus? An MRS Study in Patients with MS.

BACKGROUND AND PURPOSE: Repeat contrast-enhanced MR imaging exposes patients with relapsing-remitting MS to frequent administration of gadolinium-based contrast agents. We aimed to investigate the potential metabolite and neurochemical alterations of visible gadolinium deposition on unenhanced T1WI in the dentate nucleus using MRS. MATERIALS AND METHODS: This prospective study was conducted in a referral university hospital from January 2020 to July 2021. The inclusion criteria for case and control groups were as follows: 1) case: patients with relapsing-remitting MS, visible gadolinium deposition in the dentate nucleus (ribbon sign), >5 contrast-enhanced MR images obtained; 2) control 1: patients with relapsing-remitting MS without visible gadolinium deposition in the dentate nucleus, >5 contrast-enhanced MR images obtained; 3) control 2: patients with relapsing-remitting MS without visible gadolinium deposition in the dentate nucleus, <5 contrast-enhanced-MR images obtained; and 4) control 3: adult healthy individuals, with no contrast-enhanced MR imaging. Dentate nucleus and pontine single-voxel 12 × 12 × 12 MRS were analyzed using short TEs. RESULTS: Forty participants (10 per group; 27 [67.5%] female; mean age, 35.6 [SD, 9.6] years) were enrolled. We did not detect any significant alteration in the levels of NAA and choline between the studied groups. The mean concentrations of mIns were 2.7 (SD, 0.73) (case), 1.5 (SD, 0.8) (control 1), 2.4 (SD, 1.2) (control 2), and 1.7 (SD, 1.2) (control 3) (P = .04). The mean concentration of Cr and mIns (P = .04) and the relative metabolic concentration (dentate nucleus/pons) of lipid 1.3/Cr (P = .04) were significantly higher in the case-group than in healthy individuals (controls 1-3). Further analyses compared the case group with cumulative control 1 and 2 groups and showed a significant increase in lactate (P = .02), lactate/Cr (P = .04), and Cr (dentate nucleus/pons) (P = .03) in the case group. CONCLUSIONS: Although elevated concentrations of Cr, lactate, mIns, and lipid in the dentate nucleus of the case group indicate a metabolic disturbance, NAA and choline levels were normal, implying no definite neuronal damage.

Value of Emergent Neurovascular Imaging for "Seat Belt Injury": A Multi-institutional Study.

BACKGROUND AND PURPOSE: Screening for blunt cerebrovascular injury in patients after motor vehicle collision (MVC) solely based on the presence of cervical seat belt sign has been debated in the literature without consensus. Our aim was to assess the value of emergent neurovascular imaging in patients after an MVC who present with a seat belt sign through a large-scale multi-institutional study. MATERIALS AND METHODS: The electronic medical records of patients admitted to the emergency department with CTA/MRAs performed with an indication of seat belt injury of the neck were retrospectively reviewed at 5 participating institutions. Logistic regression analysis was used to determine the association among age, sex, and additional trauma-related findings with blunt cerebrovascular injury. RESULTS: Five hundred thirty-five adult and 32 pediatric patients from June 2003 until March 2020 were identified. CTA findings were positive in 12/567 (2.1%) patients for the presence of blunt cerebrovascular injury of the vertebral (n = 8) or internal carotid artery (n = 4) in the setting of acute trauma with the seat belt sign. Nine of 12 patients had symptoms, signs, or risk factors for cervical blunt cerebrovascular injury other than the seat belt sign. The remaining 3 patients (3/567, 0.5%) had Biffl grades I-II vascular injury with no neurologic sequelae. The presence of at least 1 additional traumatic finding or the development of a new neurologic deficit was significantly associated with the presence of blunt cerebrovascular injury among adult patients, with a risk ratio of 11.7 (P = .001). No children had blunt cerebrovascular injury. CONCLUSIONS: The risk of vascular injury in the presence of the cervical seat belt sign is small, and most patients diagnosed with blunt cerebrovascular injury have other associated findings. Therefore, CTA based solely on this sign has limited value (3/567 = a 0.5% positivity rate). We suggest that in the absence of other clinical findings, the seat belt sign does not independently justify neck CTA in patients after trauma.

Radiologically Isolated Syndrome: A Review for Neuroradiologists.

Radiologically isolated syndrome refers to an entity in which white matter lesions fulfilling the criteria for multiple sclerosis occur in individuals without a history of a clinical demyelinating attack or alternative etiology. Since its introduction in 2009, the diagnostic criteria of radiologically isolated syndrome and its clinical relevance have been widely debated by neurologists and radiologists. The aim of the present study was to review the following: 1) historical evolution of radiologically isolated syndrome criteria, 2) clinical and imaging findings in adults and children with radiologically isolated syndrome, 3) imaging features of patients with radiologically isolated syndrome at high risk for conversion to MS, and 4) challenges and controversies for work-up, management, and therapeutic interventions of patients with radiologically isolated syndrome.

Parental Leave and Neuroradiology Fellowships.

BACKGROUND AND PURPOSE: A uniform policy on parental leave in radiology training programs is lacking. Although previous publications have addressed the status of parental leave policy among radiology residency programs, the state of parental leave in radiology fellowships has not been addressed to date. Our aim was to determine the state of parental leave policies in American neuroradiology fellowship programs. MATERIALS AND METHODS: An Internet survey was sent to the directors of neuroradiology fellowship programs listed on the Accreditation Council for Graduate Medical Education Web site (n = 87) in January 2020. The questionnaire assessed the policies of the fellowship programs and Program Directors' attitudes toward maternal and paternal leave. Four reminders were sent during the 3 weeks before closing data collection. RESULTS: The response rate was 76% (66/87). Ninety-four percent (62/66) of program directors claimed to have a maternal leave policy, of which 51/62 (82%) were written and 53/62 (85%) were paid. Additionally, 77% (51/66) had a policy for paternal leave, of which 80% (41/51) were written and 76% (39/51) were paid. The average length of paid leave was 6.7 ± 3.25 weeks for new mothers and 2.9 ± 2 weeks for new fathers. Unpaid leave was mostly based on the Family and Medical Leave Act. Fellows were responsible for making up call duties during the parental leave in 47% of the programs. Radiation exposure was restricted in 89% of the programs during pregnancy. Policies addressed breast feeding and untraditional parenthood in just 41% of the responding programs. Most program directors supported the development of a unified national policy on maternal (83%) and paternal (79%) leave. CONCLUSIONS: Most neuroradiology fellowship programs have explicit maternal and paternal leave policies that grant paid leave to trainees. Some also offer unpaid leave, mostly through Family and Medical Leave Act guidelines. A uniform policy derived from the Accreditation Council for Graduate Medical Education and/or American Board of Radiology would be useful and overwhelmingly accepted.

Redundant Neurovascular Imaging: Who Is to Blame and What Is the Value?

BACKGROUND AND PURPOSE: Excessive use of neurovascular imaging studies such as Doppler ultrasound, CTA, MRA, and DSA adds cost to the evaluation of patients with new neurologic deficits. We sought to determine to what extent redundant neurovascular imaging is generated by radiologists' recommendations and the agreement rates among modalities in this setting. MATERIALS AND METHODS: The radiology reports of 300 consecutive patients admitted for acute stroke to determine the frequency of the following: 1) >1 neurovascular study performed, 2) recommendation for another study, 3) recommendation made by the radiologist, and 4) agreement rates among these redundant neurovascular imaging studies. RESULTS: Among the 300 consecutive patients, 125 had redundant neurovascular imaging, accounting for 144 redundant studies. These included 75/125 redundant neurovascular imaging studies after MRA, 48/125 after CTA, and 2/125 after Doppler ultrasound. The radiologist recommended another vascular study in 22/125 (17.6%) patients; the rest of the recommendations were made by clinicians. The second study agreed with the first in 54.6% (12/22) of cases recommended by radiologists and 73.8% (76/103) recommended by clinicians (P value = .06). CTA agreed with MRA, carotid Doppler ultrasound, and DSA in 66.7%, 66.7%, and 55.6%, respectively. MRA agreed with Doppler ultrasound and DSA in 78.3% and 66.7%, respectively. CONCLUSIONS: Of cases with redundant neurovascular imaging, most were generated by clinicians, but radiologists recommended redundant neurovascular imaging in 17.6% of patients; 81.8% occurred following MRA. Overall, most secondary studies (68.8%) confirmed the findings of the first study. Such low-value, same-result redundant neurovascular imaging was more common when clinicians ordered the studies (73.8%) than when radiologists ordered them (54.6%).

Bias in Neuroradiology Peer Review: Impact of a "Ding" on "Dinging" Others.

BACKGROUND AND PURPOSE: The validity of radiology peer review requires an unbiased assessment of studies in an environment that values the process. We assessed radiologists' behavior reviewing colleagues' reports. We hypothesized that when a radiologist receives a discrepant peer review, he is more likely to submit a discrepant review about another radiologist. MATERIALS AND METHODS: We analyzed the anonymous peer review submissions of 13 neuroradiologists in semimonthly blocks of time from 2016 to 2018. We defined a discrepant review as any one of the following: 1) detection miss, clinically significant; 2) detection miss, clinically not significant; 3) interpretation miss, clinically significant; or 4) interpretation miss, clinically not significant. We used random-effects Poisson regression analysis to determine whether a neuroradiologist was more likely to submit a discrepant report during the semimonthly block in which he or she received one versus the semimonthly block thereafter. RESULTS: Four hundred sixty-eight discrepant peer review reports were submitted; 161 were submitted in the same semimonthly block of receipt of a discrepant report and 325 were not. Receiving a discrepant report had a positive effect on submitting discrepant reports: an expected relative increase of 14% (95% CI, 8%-21%). Notably, receiving a clinically not significant discrepant report (coefficient = 0.13; 95% CI, 0.05-0.22) significantly and positively correlated with submitting a discrepant report within the same time block, but this was not true of clinically significant reports. CONCLUSIONS: The receipt of a clinically not significant discrepant report leads to a greater likelihood of submitting a discrepant report. The motivation for such an increase should be explored for potential bias.

Gadolinium and Multiple Sclerosis: Vessels, Barriers of the Brain, and Glymphatics.

The pathogenesis of multiple sclerosis is characterized by a cascade of pathobiologic events, ranging from focal lymphocytic infiltration and microglia activation to demyelination and axonal degeneration. MS has several of the hallmarks of an inflammatory autoimmune disorder, including breakdown of the BBB. Gadolinium-enhanced MR imaging is currently the reference standard to detect active inflammatory lesions in MS. Knowledge of the patterns and mechanisms of contrast enhancement is vital to limit the radiologic differential diagnosis in the staging and evaluation of MS lesion activity. The aim of this review was the following: 1) to outline the pathophysiology of the effect of lymphocyte-driven inflammation in MS, 2) to describe the effects of gadolinium on the BBB and glymphatic system, and 3) to describe gadolinium enhancement patterns and artifacts that can mimic lesions in MS.

The Top 20 Most Prolific Authors in the American Journal of Neuroradiology: What Is Their Impact?

BACKGROUND AND PURPOSE: Many articles that are relevant to patient care but published in radiology journals may escape notice by clinicians. We sought to determine how often the 20 most prolific American Journal of Neuroradiology (AJNR) authors from 2013 to 2017 published in clinical journals and the extent to which their articles were disseminated into the clinical literature. MATERIALS AND METHODS: We counted all authors' first- or senior-authored articles in the AJNR from 2013 to 2017 to identify the 20 most prolific authors in AJNR. We searched for these 20 authors' total articles from 2013 to 2017 to determine which were published in radiology or clinical journals and the number of citations received from radiology and clinical journals. Authors were sorted into quartiles according to these metrics, and other descriptive statistics were performed. RESULTS: The top 20 AJNR authors contributed to 1463 articles during 5 years, including 711 (48.6%) in radiology and 752 (51.4%) in clinical journals. These articles were cited 15,857 times, including 4659 (29.3%) by articles in radiology journals. The more prolific authors published in clinical journals more often (Spearman ρ = 0.65, P = .002) and were cited more (ρ = 0.42, P = .07). Articles published in clinical journals were cited more often (mean, 12.3 clinical, 9.3 radiology general versus 8.7 in AJNR), and whether published in radiology or clinical journals, they were cited more frequently by clinical journals. CONCLUSIONS: Regardless of where it is published, radiology research is disseminating into the clinical realm. Radiology articles published in clinical journals are cited more often than those published in radiology journals.

Perspectives on Neuroradiology Medical Expert Testimony: Fact and Fiction.

There are numerous misconceptions about serving as a medical malpractice expert witness. By maintaining an objective perspective based in the unbiased interpretation of the images provided (for both sides of the conflict), one can best serve society as a whole. Most cases for which a neuroradiology expert is recruited are the following: 1) not with the radiologist as a defendant, 2) resolved without court testimony, and 3) short-lived if frivolous. One can learn much about medicine, our nonradiology colleagues, and the litigation process by participating as an expert witness.

Who's Contributing Most to American Neuroscience Journals: American or Foreign Authors?

BACKGROUND AND PURPOSE: With globalization, the contributions of authors from abroad to the American published literature has increased. We sought to determine the changes with time in the proportional contributions of American and non-American authors in the American neurosciences literature. We hypothesized the following: 1) During the past 21 years, manuscript contributions of American institutions have proportionally decreased in neuroradiology, more than in neurosurgery or neurology; 2) contributions of Asian institutions have affected neuroradiology more than neurosurgery and neurology; and 3) American articles garner more citations. MATERIALS AND METHODS: We reviewed the May issues of 2 of the highest impact American-based neurology, neurosurgery, and neuroradiology journals published from 1997 to 2017. We counted the number of articles published by nation based on the institution of origin. We looked at trends across time and compared neurology, neurosurgery, and neuroradiology journals. We also gathered data on the number of citations of each article by nationality. RESULTS: We reviewed 3025 articles. There was a significantly lower ratio of American to non-American authorship in neuroradiology versus neurology/neurosurgery journals (odds ratio = 0.70; 95% confidence interval, 0.60-0.82). There was a significantly decreasing trend in American authorship across the 21 years in neuroradiology. Of the countries outside the United States, Japan contributed most for neuroradiology and neurosurgery journals, and the UK, for neurology. American-authored articles were cited, on average, 1.25 times more frequently than non-American-authored articles. CONCLUSIONS: Non-American contributions have impacted neuroradiology more than other clinical neuroscience fields with Asian authorship showing the greatest impact. That impact is growing, and the causes are manifold. Nonetheless American-authored articles are cited more.

Revenue Increase following 2017 Multiple Procedures Payment Reduction Modification: Differential Impact on Neuroradiology-Report from an Academic Medical Center.

BACKGROUND AND PURPOSE: The Centers for Medicare and Medicaid Services imposed a 25% professional component multiple procedure payment reduction for the professional component of advanced diagnostic imaging modalities in January 2012. In 2017, the Centers for Medicare and Medicaid Services rolled back the multiple procedure payment reduction to 5% for subsequent imaging. To evaluate the effect of this change, we analyzed 5 months of Centers for Medicare and Medicaid Services procedures at Johns Hopkins Medical Institution. MATERIALS AND METHODS: We analyzed the procedure codes and reimbursement rate for studies performed between January 1 and May 31, 2017. Patients with Medicare insurance who had multiple diagnostic procedures in a day were selected. Per the Centers for Medicare and Medicaid Services guidelines, procedures with the highest price were considered fully reimbursed and subsequent studies were marked for differences between 25% (2013-2016) and 5% reduction (2017). RESULTS: We included 8787 patients with 22,236 procedures (mean, 2.53 studies/day). CT, MR imaging, and ultrasound scans composed 75.9%, 21.5%, and 2.6% of all studies, with 61.2%, 54.9%, and 85.4% of the procedures of each technique subject to multiple procedure payment reduction, respectively. The projected reimbursement for these studies was $1,666,437, which translated to a $179,782 (12.1%) increase in revenue comparing 25%-versus-5% multiple procedure payment reduction rates for 5 months: $128,542 for CT, $47,802 for MR imaging, and $3439 for ultrasound. The annual overall prorated increase in revenue would be $431,476. The impact was maximal for neuroradiology. CONCLUSIONS: With the recent favorable adjustment in multiple procedure payment reduction regulations, CT-heavy subspecialties like neuroradiology benefit the most with revenue increases. Different practice settings might experience revenue increases to a different extent, depending on the procedure and payer mix.

Syringohydromyelia in Patients with Chiari I Malformation: A Retrospective Analysis.

BACKGROUND AND PURPOSE: The association of syringohydromyelia with Chiari I malformation has a wide range, between 23% and 80% of cases in the current literature. In our experience, this range might be overestimated compared with our observations in clinical practice. Because there is an impact of Chiari I malformation-associated syringohydromyelia on morbidity and surgical intervention, its diagnosis is critical in this patient population. Identifying related variables on the basis of imaging would also help identify those patients at risk of syrinx formation during their course of disease. MATERIALS AND METHODS: We performed a retrospective analysis of the MR imaging studies of 108 consecutive cases of Chiari I malformation. A multitude of factors associated with syrinx formation were investigated, including demographic, morphometric, osseous, and dynamic CSF flow evaluation. RESULTS: Thirty-nine of 108 (36.1%) patients with Chiari I malformation had syringohydromyelia. On the basis of receiver operating characteristic curve analysis, a skull base angle (nasion-sella-basion) of 135° was found to be a statistically significant classifier of patients with Chiari I malformation with or without syringohydromyelia. Craniocervical junction osseous anomalies (OR = 4.3, P = .001) and a skull base angle of >135° (OR = 4.8, P = .0006) were most predictive of syrinx formation. Pediatric patients (younger than 18 years of age) who developed syringohydromyelia were more likely to have associated skull base osseous anomalies than older individuals (P = .01). CONCLUSIONS: Our findings support evidence of the role of foramen magnum blockage from osseous factors in the development of syringohydromyelia in patients with Chiari I malformation.

Pretreatment ADC Values Predict Response to Radiosurgery in Vestibular Schwannomas.

BACKGROUND AND PURPOSE: The response rate of vestibular schwannomas to radiation therapy is variable, and there are surgical options available in the event of treatment failure. The aim of this study was to determine whether pre- and posttreatment ADC values can predict the tumor response to radiation therapy. MATERIALS AND METHODS: From a data base of 162 patients with vestibular schwannomas who underwent radiation therapy with gamma knife, CyberKnife, or fractionated stereotactic radiation therapy as the first-line therapy between January 2003 and December 2013, we found 20 patients who had pretreatment ADC values. There were 108 patients (including these 20) had serial MR images that included DWI allowing calculated ADC values from 2-132 months after radiation therapy. Two reviewers measured the mean, minimum, and maximum ADC values from elliptical ROIs that included tumor tissue only. Treatment responders were defined as those with a tumor total volume shrinkage of 20% or more after radiation therapy. RESULTS: The pretreatment mean minimum ADC for nonresponders was 986.7 × 10-6 mm2/s (range, 844-1230 × 10-6 mm2/s) and it was 669.2 × 10-6 mm2/s (range, 345-883 × 10-6 mm2/s) for responders. This difference was statistically significant (P < .001). Using a minimum ADC value of 800 × 10-6 mm2/s led to the correct classification of 18/20 patients based on pretreatment ADC values. The intraclass correlation between reviewers was 0.61. No posttreatment ADC values predicted response. CONCLUSIONS: Pretreatment ADC values of vestibular schwannomas are lower in responders than nonresponders. Using a minimum ADC value of 800 × 10-6 mm2/s correctly classified 90% of cases.