Abstract
Introduction In a retrospective magnetic resonance imaging (MRI)-based study, we showed that changes
of the third ventricle diameter (TVD) are a reliable mirror of changes of the entire
ventricular system. The third ventricle is easily accessible in more than 90% of children
and adults using ultrasound (US) via the transtemporal bone-window; thus it can be
assessed quickly and free of radiation. In order to use transtemporal US determination
of TVD instead of MRI/CT in clinical practice, it is important to know if there is
a correlation and bias between both methods, which is addressed in this study.
Materials and Method This prospective study investigates 122 children (newborn–18 years). Diagnoses encompassed
hydrocephalus (50%), tumors (14.8%), and other intracranial pathologies (35.2%). US-based
TVD was measured via the transtemporal bone-window using a phased array 1 to 4MHz
transducer. Results were compared with TVD measured on simultaneously acquired axial
T1-weighted axial MRI or computed tomography (CT) scans.
Results Overall mean values for TVD were 6.56 ± 5.84 and 6.47 ± 5.64 mm for US and MRI, respectively.
There was an outstanding correlation between TVD measured by MRI and US (r = 0.991, p < 0.01). Bland–Altman analysis showed a mean bias of 0.096 mm with limits of agreement
of –0.99 and 1.18 mm.
Conclusion US- and MRI-based TVD measurements correlate excellently and measure almost identical
TVD values. US-based TVD is in mean ∼0.096 mm larger than MRI-based TVD due to a more
angulated measurement plane. US is equal to the gold-standard MRI, a fact, opening
new avenues for US-based TVD as a first-line assessment tool of ventricular width.
Keywords
ventricular system - third ventricle diameter - US- and MRI-based TVD - hydrocephalus
- TVD
