Wood, Christopher P.

ABSTRACTPURPOSEInvestigate the relative frequency of nonlesional versus lesional hypertrophic olivary degeneration (HOD) and potential explanations for nonlesional HOD.METHODSOur radiology report database was queried for “HOD” in all head MRI reports between 7/1/2002 and 7/1/2013 and identified 138 patients. Specific absence of HOD or cases with lesions within the dento‐rubro‐olivary pathway (DROP) or extending into the inferior olivary nuclei (ION) were excluded (22 in total). For included patients, 19 locations with the anatomic potential to connect to the ION or DROP were reviewed and grouped into embryological categories, along with the use of the drug metronidazole.RESULTSA total of 51 of 116 (44%) HOD patients did not have a causative lesion in the DROP. The 27/51 (53%) of these patients had progressive ataxia with palatal tremor (PAPT). The 28/51 (55%) patients had one or more lesions outside of the DROP and one of these 28 patients used metronidazole. The remaining 23/51 (45%; 19% of total HOD cohort) patients had no additional lesions in the brain and 6 of these 23 patients did not have a clinical diagnosis of PAPT.CONCLUSIONForty‐four percent of patients with HOD did not demonstrate an MRI‐identifiable lesion in the DROP, and 45% of those patients did not have identifiable brain lesions outside of the DROP. Thus, nearly a fifth of HOD cases may be truly idiopathic. A majority of patients without a DROP lesion had bilateral HOD and two‐thirds were male.

ABSTRACTBACKGROUND AND PURPOSERequests for after‐hours emergent spine MR imaging seem to be increasing. We sought to review the trend in after hours spine MRI utilization at our institution and to determine how these results impacted therapeutic intervention.METHODSFollowing Institutional Review Board approval, reports from 179 after hours spinal MRI's performed over the past 13 years were obtained and the relevant electronic medical records were reviewed.RESULTSEmergent after hours spine MRI utilization increased from 7 per year to 23 over 13 years. Fifty‐eight percent (104/179) had significant findings. Twenty‐nine percent (52/179) of all patients imaged underwent surgery to treat pathologies identified on MR. Surgery was performed in only 2% (4/179) of these patients within 3 hours and 6% (10/179) within 6 hours of MRI completion. Five percent (8/179) had findings that were treated with radiation therapy and in 78% of these it was performed within 6–12 hours. Of those in whom steroids or antibiotics were initiated, 41% and 50% were treated within 3 hours of MR scanning, respectively.DISCUSSIONClinical use of emergent after hours spine MRI is steadily increasing at our institution. While MR imaging often discerned significant pathologies, performing these emergent studies rarely resulted in immediate surgical or radiotherapeutic intervention.

IntroductionAbandoned cardiovascular implantable electronic device (CIED) leads remain a contraindication to magnetic resonance imaging (MRI) studies, largely due to in vitro data showing endocardial heating secondary to the radiofrequency field. We tested the hypothesis that abandoned CIED leads do not pose an increased risk of clinical harm for patients undergoing MRI.MethodsThis single‐center retrospective study examined the outcomes of patients who had device generators removed before MRI, rendering the device leads abandoned. Information was gathered through chart review. Data collected included lead model, pacing threshold before MRI, anatomic region examined, threshold data after generator reimplantation, and clinical patient outcome.ResultsPatients (n = 19, 11 men and eight women) ranged in age from 19 to 85 at the time of MRI. There was a mean of 1.63 abandoned leads at the time of imaging; none of the leads were MRI conditional. Of the three implantable cardioverter defibrillator (ICD) leads, two of three were dual coil. Most (31/35) of the scans performed were of the central nervous system, including head and spinal imaging. There were no adverse events associated with MRI in any of these patients with abandoned leads within 7 days of the scan. No lead malfunctions or clinically significant change in pacing thresholds were noted with generator reimplantation.ConclusionThe use of MRI in patients with abandoned cardiac device leads appears feasible when performed under careful monitoring, with no adverse events, although the experience is small. MRI did not affect the function of leads that were subsequently reconnected to a cardiac device.

ABSTRACTBACKGROUND AND PURPOSEHypertrophic olivary degeneration (HOD) is an uncommon type of transneuronal degeneration. Case reports and case series described in the literature provide a foundation of our current knowledge of HOD. These reports have described HOD most frequently to be unilateral and occurring in association with lesions in the dentato‐rubro‐olivary pathway. Our purpose was to evaluate the rate of bilateral versus unilateral HOD in a large case series.METHODSA retrospective review was performed to identify patients in which the phrase “hypertrophic olivary degeneration” occurred in the radiology report. A diagnosis of HOD was confirmed on imaging if there was focal hyperintensity on T2‐weighted images confined to either or both inferior olivary nuclei.RESULTSA total of 102 patients had findings consistent with HOD. Of these, 76% had findings bilaterally. In 44%, a lesion could not be identified to explain HOD. Bilateral HOD was common in both lesional and nonlesional group, though more common in the nonlesional group.CONCLUSIONThis study demonstrates that HOD is frequently bilateral. In slightly over 50% of patients with HOD, a lesion can be identified. In just under 50% patients with HOD, a lesion could not be identified and in these cases HOD was present bilaterally in the majority.

ABSTRACTTwo valuable confirmatory MRI findings of acute spinal cord infarct are highlighted and discussed: concomitant vertebral body infarct and ventral cauda equina nerve root enhancement.

OBJECTIVE:To assess the magnetic resonance imaging (MRI) safety of titanium middle ear prostheses at 3.0 tesla (T).STUDY DESIGN AND SETTING:Titanium middle ear prostheses from 3 commercial vendors were examined for magnetic field interactions at 3 T. Initially, ex vivo studies were performed to test for rotational motion and forward displacement (translational motion) of the prostheses in a static magnetic field. If movement was observed during this screening study, then the prosthesis was tested to determine the translational or rotational force acting upon the prosthesis. In addition to testing for prosthesis displacement, temperature changes of the prostheses were measured to assess for radiofrequency heating during imaging.RESULTS:Twenty‐one of the 24 titanium prostheses tested revealed no movement when tested in the 3 T static magnetic field. Three prostheses revealed minimal movement during the screening study. A translational force test (string test) was performed upon these 3 prostheses, and the measured angle of displacement was used to determine the force. This calculated force acting upon each prosthesis was essentially zero. Therefore, we conclude that the magnetic field interaction is negligible. A positive control with a ferromagnetic stainless steel prosthesis demonstrated obvious displacement during the screening study, as well as deflection of the prosthesis by 90° in the translational force test. Last, heating of the titanium prostheses did not occur in the 7 models tested.CONCLUSIONS:Middle ear prostheses made from titanium are safe, neither deflecting nor heating during magnetic resonance examinations conducted at 3 T. EBM rating: C‐1.