1. 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

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

3. 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

4. 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

5. 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

6. 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

7. 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

8. 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

9. 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%

10. 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%

11. 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

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

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

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

15. 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)

16. 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

17. 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

18. 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)