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Diagnostic Accuracy of Magnetic Resonance Imaging Using Unenhanced Techniques for Detection of Recurrent Vestibular Schwannomas Jamie Williams MD, Carrie Carr MD, Laurence Eckel MD, John Lane MD ASNR 54th Annual Meeting May 2016 eP-85 ©2016 MFMER | slide-1 Disclosures • None ©2016 MFMER | slide-2 Purpose Background: Vestibular schwannomas • Benign, slowing growing tumor arising from 8th cranial nerve • Varied patterns of growth after diagnosis: • 40-50% show no growth • 40-50% demonstrate growth • <10% demonstrate regression • Management strategies: • Active surveillance vs. • Surgery, with goal to resect tumor and salvage facial nerve Nikolopoulos et al. (2010) ©2016 MFMER | slide-3 Purpose Background: Post-operative surveillance • Poor correlation between tumor growth and symptoms • Approximately 6% 3-year recurrence rate after resection • Increased risk of recurrence: subtotal resection, nodular enhancement on initial postoperative MRI • On average, recurrent growth is approximately 2.3 mm/year • MRI with gadolinium-enhanced T1 weightedimaging (T1WI) is current gold standard for recurrence Rosenberg (2000) Carlson et al. (2012) ©2016 MFMER | slide-4 Purpose Background: Gadolinium-enhanced MRI • Duration and cost of gadoliniumenhanced MRIs are greater than noncontrast MRIs • Recent evidence of gadolinium deposition in neuronal tissue after intravenous exposure to gadolinium-based contrast agents results • Dose-dependence relationship • Clinical significance unknown McDonald et al. (2015) ©2016 MFMER | slide-5 Purpose Background: Noncontrast, high resolution MRI (3D T2/T2*) • High signal-to-noise ratio per unit of time • Abele et al. (2009) demonstrated high accuracy, specificity, and sensitivity of 3D T2/T2* in detection of small internal auditory canal lesions Schleffler & Lehnhardt (2003) Abele et al. (2009) ©2016 MFMER | slide-6 Purpose Objectives • Evaluate the diagnostic accuracy of noncontrast, high resolution MRI (3D T2/T2*) for the detection of vestibular schwannoma growth following surgical resection • Potential with 3D T2/T2* to: • Reduce time and cost of scanning • Avoid patient exposure to gadolinium (and therefore gadolinium tissue deposition) ©2016 MFMER | slide-7 Material and Methods Retrospective Chart Review • Data abstracted from electronic medical record • Included patients who underwent resection Jan. 2001 to Jan. 2011: • Experienced recurrence during follow-up thru January 2015 (N=13) • Received 3D T2/T2* and contrast enhanced MRI after resection (n=41) ©2016 MFMER | slide-8 Material and Methods Summary of Cases Number of patients Total number of follow-up MRIs examined 13 41 Age at treatment, yr, mean (range) 50 (21-86) Sex, no. Female Male Pre-treatment tumor size, mm, mean (range) 9 4 19 (6-40) Side of tumor, no. Right Left Year of initial surgery, range Type of initial resection, no. Gross Total Resection Near Total Resection Subtotal Resection Number of follow-up MRIs per patient, mean (range) Year of follow-up MRIs 6 7 2002-2011 4 1 8 3.2 (1-6) 2005-2014 Underwent 2nd treatment with gamma knife during follow-up Yes No 7 6 ©2016 MFMER | slide-9 Material and Methods Retrospective Review of Follow-up MRIs • Three blinded CAQ neuroradiologists retrospectively reviewed all follow-up MRIs: • Only axial 3D T2/T2* images • Only axial gadolinium-enhanced thin-section T1-weighted images (PostGad T1WI) • For each, respective images from initial postsurgical MRI was provided for comparison • Asked to assess for presence or absence of tumor progression ©2016 MFMER | slide-10 Material and Methods Example of Retrospective Review Initial Postop MRI 3D T2/T2* PostGad T1WI Surveillance MRI vs. vs. +/Progression? +/Progression? Neuroradiologist ©2016 MFMER | slide-11 Material and Methods Data Analysis • Evaluated agreement between examiners within each sequence • For each examiner, determined whether progression was detected more frequently with one sequence versus the other ©2016 MFMER | slide-12 Results Examiner Agreement Sequence Krippendorff’s alpha 3D T2/T2* 0.815 PostGad T1WI 0.826 • Krippendorff’s angle • Ranges between –infinity and 1 • 1= Perfect agreement • ≥0.800 typically accepted as high agreement Therefore, high agreement between the examiners on both sequences ©2016 MFMER | slide-13 Results Examiner 1 Post Gad No progression Post Gad Progression Total 3D T2/T2* No progression 24 4 28 3D T2/T2* Progression 2 11 13 Total 26 15 41 McNemar’s test p-value = 0.69 Examiner 1: No difference in detection of progression between the sequences. ©2016 MFMER | slide-14 Results Examiner 2 Post Gad No progression Post Gad Progression Total 3D T2/T2* No progression 27 3 30 3D T2/T2* Progression 1 10 11 Total 28 13 41 McNemar’s test p-value = 0.63 Examiner 1: No difference in detection of progression between the sequences. ©2016 MFMER | slide-15 Results Examiner 3 Post Gad No progression Post Gad Progression Total 3D T2/T2* No progression 22 3 30 3D T2/T2* Progression 2 14 11 Total 24 17 41 McNemar’s test p-value = 0.99 Examiner 1: No difference in detection of progression between the sequences. ©2016 MFMER | slide-16 Results Interesting Case 1: Progression detected earlier on PostGad T1WI Initial Postop MRI 3D T2/T2* PostGad T1WI First Surveillance MRI Sequential Follow-up MRI All 3 examiners: No Progression All 3 examiners: Progression On the sequential follow-up MRI, all 3 examiners reported, on both sequences, that there had been progression since initial postoperative MRI ©2016 MFMER | slide-17 Results Interesting Case 2: Progression detected earlier on bSSFP Initial Postop MRI 3D T2/T2* PostGad T1WI Follow-up MRI Sequential Follow-up MRI All 3 examiners: Progression All 3 examiners: No Progression On the sequential follow-up MRI, 2/3 examiners on the 3D T2/T2* and 3/3 examiners on the PostGad T1WI reported that there had been progression since the initial preoperative MRI ©2016 MFMER | slide-18 Results Interesting Case 3: Subtle progression detected on both sequences Initial Postop MRI 3D T2/T2* PostGad T1WI Follow-up MRI All 3 examiners: Progression All 3 examiners: Progression Although the progression was subtle, 3/3 examiners detected it on both sequences. ©2016 MFMER | slide-19 Discussion Limitations • Retrospective • Many patients in this study had their surveillance MRIs performed locally • Variable image quality secondary to various scanners and protocols • Variable frequency of follow-up MRIs • Some MRIs had to be excluded from the study due to lack of 3D T2/T2* technique • Early follow-up MRIs (prior to 2005) • Some examinations from outside institutions ©2016 MFMER | slide-20 Conclusions • No substantial difference in the diagnostic accuracy between high resolution, noncontrast MRI (3D T2/T2*) and gadolinium-enhanced T1-weighted MRI for the detection of recurrent vestibular schwannomas ©2016 MFMER | slide-21 References Adele TA, Besachio DA, Quigley RK, et al. Diagnostic accuracy of screening MR imaging using unenhanced axial CISS and coronal T2WI for detection of small internal auditory canal lesions. AJNR Am J Neuroradiol 2014 July17. [Epub ahead of print] Carlson ML, Van Abel KM, Driscoll CL, et al. Magnetic resonance imaging surveillance following vestibular schwannoma resection. Larnygoscope 2012;122:378-388 McDonald RJ, McDonald JS, Kallmes DF, et al. Intracranial gadolinium deposition after contrast-enhanced MR imaging. Radiology 2015; 275(3):772-782 Nikolopoulos TP, Fortnum H, O’Donoghue G, Baguley D. Acoustic neuroma growth: a systemic review of the evidence. Oto Neurotol 2010;31:478-485 Rosenbeerg SI. Natural history of acoustic neuromas. Laryngoscope 2000;110;497-508 Scheffler K and Lehnhardt S. Principles and applications of balanced SSFP techniques. Eur Radiol 2003;13:24092418 ©2016 MFMER | slide-22 Thank you for your time and attention. Please address correspondence to Jamie Williams MD, Department of Radiology Mayo Clinic Rochester, email [email protected] ©2016 MFMER | slide-23