gms | German Medical Science

Objective: We previously proved that changes of TVD in MRI scans are a reliable mirror of changes of the lateral ventricles. Since the third ventricle is easily accessible in more than 90% of children and adults using ultrasound via the transtemporal bone window, US assessment of TVD would be most helpful in clinical routine care of patients with hydrocephalus This study aims to investigate whether there is a good correlation between US and MRI based TVD and if both methods measure the same value.

Methods: This prospective study includes 52 patients aged newborn to 18 years. Diagnoses encompassed hydrocephalus (50%), tumor (13.5%) and various other pathologies (36.5%). TVD was measured by transtemporal window using a phased-array 1-4 MHz transducer with patient in supine position. Mean TVD was created out of 3 measurements. This was compared to TVD on T1 weighted axial MRI of the brain which were simultaneously (usually within 24 hours) aquired.

Results: Overall mean values for TVD were 6.44 ± 5.27 and 6.29 ± 4.94 mm for ultrasound and MRI, respectively. There was a strong positive correlation between TVD measured on MRI compared to ultrasound (r= 0.982, p< 0.01). Bland and Altman analysis of the two methods showed a mean bias of 0.15 mm with limits of agreement of -1.37 and 1.67 mm. 98% of the values were within the limits of agreement.

Conclusion: US and MRI based measurements of TVD are well comparable, but US TVD is in mean about 0.15 mm larger than MRI TVD, most likely due to a more angulated assessment. When considering this offset, ultrasound TVD can be used for follow-up evaluations of ventricular width in neurosurgery instead of MRI scans.