Carr, Carrie M.

Background: Gadolinium-enhanced T1-weighted magnetic resonance imaging (MRI) (T1WI) is the conventional imaging technique of choice to detect vestibular schwannoma (VS) recurrence or regrowth, despite suboptimal specificity secondary to enhancing postoperative changes. Furthermore, recent concerns regarding the accumulation of gadolinium in body tissues have led for a call to reduce the number of contrast-enhanced examinations. The objective of the current study is to evaluate the diagnostic accuracy of high-resolution noncontrast (three-dimensional [3D] T2) MRI relative to gadolinium-enhanced T1WI in the detection of VS recurrence after resection. Methods: Following Institutional Review Board approval, 13 consecutive postoperative patients with VS recurrence or regrowth were identified from a prospectively maintained clinical database in which recurrence was determined by progression on serial postoperative MRI examination. Three blinded neuroradiologists retrospectively evaluated a total of 41 postoperative MRI examinations from these patients using only gadolinium-enhanced T1WI and 3D T2 MRI for recurrence or regrowth. Interobserver agreement, differences in detection between the two sequences, and the sensitivity and specificity of 3D T2 MRI were assessed. Results: Fifteen of the 41 postoperative MRIs demonstrated progression, as determined by examiner consensus on the gadolinium-enhanced T1WI. Agreement, measured using Krippendorff's alpha, was 0.82 for the 3D T2 images and 0.83 for the contrast-enhanced T1WI. All the three examiners demonstrated no difference in the detection of progression between the two sequences (McNemar's test p values 0.69 for examiner 1, 0.63 for examiner 2, and 0.99 for examiner 3). The sensitivity of 3D T2 was 0.78 (CI 0.60–0.96), while the specificity was 0.94 (CI 0.86–1.00). Conclusion: Noncontrast high-resolution 3D T2 MRI seems sufficient to assess for recurrence or regrowth after VS resection. The results of this study have implications for reducing cost, time, and adverse events associated with gadolinium administration in this population requiring serial follow-up examinations. These promising, yet preliminary findings warrant confirmation with a larger prospective cohort of patients.

Abstract Background. Transforaminal epidural steroid injections (TFESI) have demonstrated efficacy and effectiveness in treatment of radicular pain. Despite little evidence of efficacy/effectiveness, interlaminar epidural steroid injections (ILESI) are advocated by some as primary therapy for radicular pain due to purported greater safety. Objective. To assess immediate and delayed adverse event rates of TFESI and ILESI injections at three academic medical centers utilizing International Spine Intervention Society practice guidelines. Methods. Quality assurance databases from a Radiology and two physical medicine and rehabilitation (PM&R) practices were interrogated. Medical records were reviewed, verifying immediate and delayed adverse events. Results. There were no immediate major adverse events of neurologic injury or hemorrhage in 16,638 consecutive procedures in all spine segments (14,956 TFESI; 1,682 ILESI). Vasovagal reactions occurred in 1.2% of procedures, more frequently ( P = 0.004) in TFESI (1.3%) than ILESI (0.5%). Dural punctures occurred in 0.06% of procedures, more commonly after ILESI (0.2% vs 0.04%, P = 0.006). Delayed follow up on PM&R patients (92.5% and 78.5, next business day) and radiology patients (63.1%, 2 weeks) identified no major adverse events of neurologic injury, hemorrhage, or infection. There were no significant differences in delayed minor adverse event rates. Central steroid response (sleeplessness, flushing, nonpositional headache) was seen in 2.6% of both TFESI and ILESI patients. 2.1% of TFESI and 1.8% of ILESI patients reported increased pain. No long-term sequelae were seen from any immediate or delayed minor adverse event. Conclusions. Both transforaminal and ILESI are safely performed with low immediate and delayed adverse event rates when informed by evidence-based procedural guidelines. By demonstrating comparable safety, this study suggests that the choice between ILESI and TFESIs can be based on documented efficacy and effectiveness and not driven by safety concerns.

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 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.