ASNR 53rd Annual Meeting, Chicago, April 25-30, 2015 EP-144 Pediatric brain MRI: Is axial T2-weighted imaging enough for a diagnosis? Matthias W. Wagner ¹, Marinos Kontzialis ¹, Daniel Seeburg ¹, Steven E. Stern 2, Alexander Oshmyansky 1,2, Andrea Poretti ¹, Thierry A.G.M. Huisman ¹ ¹Section of Pediatric Neuroradiology, Division of Pediatric Radiology, Russell H. Morgan Department of Radiology and Radiological Science, The Johns Hopkins University School of Medicine, Baltimore, MD, USA; ²School of Mathematical Sciences, Faculty of Science and Engineering, Queensland University of Technology, Brisbane, QLD, Australia ASNR 53rd Annual Meeting, Chicago, April 25-30, 2015

Disclosure We have nothing to disclose No relevant financial relations interfering with the presentation

Introduction ↑ financial constraints in health care  need for rapid imaging protocols Our experience: T2w images most helpful in children: ↑ water content of pediatric brain ↑ signal/noise + contrast/noise ratio ↑ anatomical resolution + ↑ high sensitivity for many pediatric brain diseases Consequently: T2w images  ↑ potential for an initial screening tool in pediatric neuroradiology

Purpose To determine the sensitivity and specificity of axial T2 weighted images in the evaluation of pediatric brain MRI studies versus Axial T2 Full study

Inclusion criteria Age at MRI < 18 years Consecutively acquired head MRIs at the Johns Hopkins Hospital only Studies with final diagnoses confirmed by neuroimaging, laboratory tests, genetic analysis, and/or pathology

Methods 1 Evaluation of axial T2 weighted images alone  first diagnosis noted Without time lapse: Evaluation of the full study  second diagnosis noted Diagnoses noted as “normal” or “abnormal” Calculation of sensitivity and specificity for abnormal studies

Methods 2 Standard of reference: final report of neuroradiology attendings as available in the PACS Three readers with different levels of experience Reader 1: 20 years pediatric neuroradiology Reader 2: neuroradiology fellow Reader 3: 4th year radiology resident Readers were blinded for clinical diagnoses and study indication 161 children (6 children scanned twice)  167 studies per reader

Results 1 Mean age of children: 7.44 ± 5.71 years Standard of reference: 91 studies “abnormal” 76 studies “normal”  Normal study: absence of any pathology except sinus / mastoid effusion

Results 2 <0.001 All readers T2 Full study p-Value Specificity 92.1% 90.4% 0.343 Sensitivity 83.2% 92.3% <0.001 NPV 82.0% 90.7% PPV 92.7% 92.0%

Results 3 Individually T2 Full study p-Value 0.041 0.013 0.003 Reader 1 (20 years) Specificity 92.1% 93.4% 1.00 Sensitivity 87.9% 94.5% 0.041 NPV 86.4% PPV 93.0% Reader 2 (2 years) 84.6% 0.013 83.3% 92.8% Reader 3 (4th year resident) 85.5% 0.131 76.9% 89.0% 0.003 86.7% 88.0%

Results 4 3 groups of false negative studies: Group 1: lack of an additional plane Sagittal: Chiari 1 / hypoplastic corpus callosum Group 2: lack of additional sequences DWI: acute stroke SWI/T2*: blood products Group 3: limited reader experience

False negatives on axial T2 Group 1: additional plane Chiari malformation type 1 Axial T2w “Unremarkable” Sagittal T1w Tonsillar herniation

False negatives on axial T2 Group 2: additional sequences Hemorrhagic diffuse axonal injury Axial T2w Unremarkable Axial T2*w Hypointense lesions

False negatives on axial T2 Group 3: reader experience Axial T2w: moyamoya disease Axial T2w: systemic lupus with cerebral atrophy

Results 5 Classification of 14 clinical indications in 2 groups: Group 1: acute clinical findings  potentially immediate consequences for patient care Group 2: non-acute clinical indications 4 false negative diagnoses in Group 1 (acute stroke, diffuse axonal injury, intraaxial hemorrhage) 2 non-acute clinical indications without misread on axial T2-screening (including >1 study): Question of malformation Follow-up for hypoxic-ischemic encephalopathy (HIE)

Studies divided by indication Number of studies False negative studies on axial T2 only Reader 1 Reader 2 Reader 3 Group 1: Acute clinical indication 19 1. Question of stroke 8 1 2. Question of tumor 7 3. Trauma 4 3 2 Group 2: Non-acute clinical indication 148 4. Non-acute neurological findings 34 5. Tumor follow-up 26 6. Seizure correlate 7. Question of malformation 18 8. Malformation follow-up 9. Phakomatosis follow-up 12 10. Developmental delay 11 11. HIE follow-up 12. Infectious disease follow-up 13. Question of phakomatosis 14. Stroke follow-up

Conclusion 1 1a. Axial T2-weighted images alone can identify abnormal studies with high reliability 1b. High level of experience further increases sensitivity and specificity

Conclusion 2 2a. False negative results make introduction of solitary axial T2-screening currently unfeasible 2b. Additional DWI + SWI sequences to a 3D- T2w sequence: ↑ imaging time, but still faster than standard protocols  possible new screening tool in children with neurologic symptoms (as alternative to CT)