Objectives: This study aimed to investigate the accuracy of conventional Sagittal Turbo
spin Echo T2-weighted (Sag TSE-T2W), variable flip angle 3D TSE (VFA-3D-TSE) and high-resolution
3D heavily T2W (HR-3D-HT2W) sequences in the diagnosis of primary aqueductal stenosis
(PAS) and Superior Medullary Velum Stenosis (SMV-S), and the effect of stenosis localization on
Methods: Seventy-seven patients were included in the study. The diagnosis accuracy of the
HR-3D-HT2W, Sag TSE-T2W and VFA-3D-TSE sequences, was classified into three grades by
two experienced neuroradiologists: grade 0 (the sequence has no diagnostic ability), grade 1 (the sequence
diagnoses stenosis but does not show focal stenosis itself or membrane formation), and
grade 2 (the sequence makes a definitive diagnosis of stenosis and shows focal stenosis itself or
membrane formation). Stenosis localizations were divided into three as Cerebral Aquaduct (CA),
Superior Medullary Velum (SMV) and SMV+CA. In the statistical analysis, the grades of the sequences
were compared without making a differentiation based on localization. Then, the effect of
localization on diagnosis was determined by comparing the grades for individual localizations.
Results: In the sequence comparison, grade 0 was not detected in the VFA-3D-TSE and HR-3DHT2W
sequences, and these sequences diagnosed all cases. On the other hand, 25.4% of grade 0
was detected with the Sag TSE-T2W sequence (P<0.05). Grade 1 was detected by VFA-3D-TSE in
23% of the cases, while grade 1 (12.5%) was detected by HRH-3D-T2W in only one case, and the
difference was statistically significant (P<0.05). When the sequences were examined according to
localizations, the rate of grade 0 in the Sag TSE-T2W sequence was statistically significantly higher
for the SMV localization (33.3%) compared to CA (66.7%) and SMV+CA (0%) (P<0.05). Localization
had no effect on diagnosis using the other sequences.
Conclusion: In our study, we found that the VFA-3D-TSE and HR-3D-HT2W sequences were successful
in the diagnosis of PAS and SMV-S contrary to the Sag TSE-T2W sequence and especially
SMV localization decreases the diagnostic accuracy of Sag TSE-T2W sequence.