OC17: Quantitative and qualitative vermis and posterior fossa evaluation by magnetic resonance imaging in fetuses with suspected abnormal findings by ultrasound examination

Abstract

Oral communication abstracts consensus by the ultrasound readers and MR readers, respectively. Consensus was significantly more likely when VM was isolated than when other anomalies were present (P < 0.0001). There were 80 cases (153 disagreements) and 94 cases (223 disagreements) without consensus on the ultrasound and MR readings, respectively. There were 30 and 29 disagreements on ultrasound and MR regarding major findings either being present or absent. There was no effect on agreement when comparing cases with consensus/decision to call VM, or no clinical difference due to disagreements vs. all other disagreements with respect to BPD, HC, GA by ultrasound or GA by dates. There was a significant difference in these groups when comparing ventricular size; fetuses with larger ventricles were more likely to have clinically important disagreements. Comparing the prospective seven readings, there were 83/196 (42%) cases with complete agreement. Comparing the consensus ultrasound opinion to the consensus MR opinion there were 135/196 (69%) cases with complete agreement. There were 32/196 (16%) cases of diagnosis disagreement. Conclusions: Disagreements regarding major findings on prenatal ultrasound and MR are common in fetuses with VM. Individual training may contribute to these disagreements. This variability should be taken into account when counseling patients with fetuses with VM.

Biometric assessments of the posterior fossa by fetal MRI: A systematic review

“…A total of 804 studies were initially screened and 59 publications were included in the final systematic review 4,5,7,15‐69 (Figure 1) (Table S1). Separate publications with duplicated data from those included were assessed 51,70‐80 …”

“…The latter was shown to be positively correlated elsewhere however 18,39,51 . In total, 15 measurements and six angles (such as TVA) were unaffected by GA. Studies comparing CM depth, lateral ventricle transverse diameter, CSOA, and inferior vermian distance (craniocaudal) with GA have been inconsistent in their findings 15,18,19,21,25,26,28,39,44,51,52,54,61,63 …”

“…Six studies looked at a diverse group of PFAs 4,7,26,39,47,68 and compared these to controls. PFAs reported included abnormalities of the cerebellum, vermis, brainstem and cisterna magna, and cysts.…”

“…The use of qualitative assessments alone of the PF in fetal MRI should no longer be common practice – qualitative assessments are not completely accurate, 7 and quantitative measurements can be combined with qualitative for a more thorough assessment 20,26,37,50,62,86 The development of centile calculators 54 should make the use of quantitative measures easier. We demonstrate here the variety of measurements currently used globally, without each adding to the diagnostic picture – consistency in use is needed to standardise the evaluation of images.…”