Impact of rater experience and referral question on detecting magnetic resonance imaging features of idiopathic intracranial hypertension

Abstract

Background and purposeIn idiopathic intracranial hypertension (IIH), magnetic resonance imaging (MRI) features are promising diagnostic markers, but the impact of rater experience and the specific referral question is unknown.MethodsFrom the Vienna Idiopathic Intracranial Hypertension database, patients were included with definitive IIH and routine cranial MRI performed during diagnostic work‐up. Frequencies of partial empty sella (ES), optic nerve sheath distension (ONSD), optic nerve tortuosity (ONT), posterior globe flattening (PGF) and transverse sinus stenosis (TSS) were compared in three settings: (i) real‐world rating, (ii) junior neuroradiologist without special IIH training and (iii) senior neuroradiologist with experience in IIH imaging (gold standard).ResultsMagnetic resonance imaging scans of 84 IIH patients (88% female, mean age 33.5 years) were evaluated. By gold standard, ONSD was the most frequent (64.3%) followed by TSS (60.0%), ONT (46.4%), ES (44.4%) and PGF (23.8%). Compared to the gold standard, IIH features were described significantly less frequently in routine MRI reports (ONSD 28.6%, ONT 13.1%, PGF 4.8%, TSS 42.9%, p < 0.01 respectively) except for ES (42.9%, p = 0.9). A specific referral question regarding IIH increased detection rates in routine reports, but rates remained significantly lower than by gold standard. In contrast, a rating by a neuroradiologist without special training produced significantly higher frequencies of ONSD (81.0%, p < 0.01) and ONT (60.7%, p < 0.01) but not of ES (47.6%), PGF (29.8%) and TSS (68.1%).ConclusionsIdiopathic intracranial hypertension MRI features are underestimated in routine MRI reports and partly overcalled by less experienced neuroradiologists, driven by features less well known or methodologically difficult. Reevaluation of MRI scans by an experienced rater (and to a lesser degree a specific referral question) improves diagnostic accuracy.

The additive value of complementing diagnostic idiopathic intracranial hypertension criteria by MRI – an external validation study

“…With respect to 100% accuracy of the updated criteria in patients without IIH, this is particularly encouraging as the rate of IIH misdiagnosis is high and incidental findings of neuroimaging signs are reported in up to 49% of patients undergoing brain MRI without clinical suspicion of IIH [ 5 , 7 ]. On the other hand, MRI signs of IIH are often underestimated and partly overcalled by less experienced neuroradiologists in clinical routine, which is likely due to insufficient training but also imperfect definitions of MRI signs [ 12 ]. Hence, a high level of precision is required, which precludes the use of isolated elevated OP or one to two neuroimaging signs as diagnostic for IIH.…”