Changes of third ventricle diameter (TVD) mirror changes of the entire ventricular system at acute shunt failure and after shunt revision in pediatric hydrocephalus

The Sonographic Motion Quantification of the Third Ventricle Wall in Occlusive Hydrocephalus: A Dynamic Diagnostic Method

This study aimed to devise a dynamic method to diagnose occlusive hydrocephalus by transcranial ultrasound. By using transcranial B-mode ultrasound and speckle tracking software, we registered cardiac-related pulsations of the lateral walls of the third ventricle. We determined the measurement location with the least variance in 24 participants using a mixed-effect model. In six patients, we used this optimized measuring procedure to obtain deformation curves before and after surgical therapy of occlusive (i.e., obstructive) internal hydrocephalus. Speckle tracking points at the lateral change of contrast delineating the wall of the third ventricle at the level of the thalami accounted for the least variance in normal subjects. Using this refined method, all normal participants showed transient lateral distension of the third ventricle. In all patients, the deformation curves before surgery clearly differed from the normal collective and showed mostly a transient reduction of ventricle diameter. In two hydrocephalus patients with operative restoration of normal cerebrospinal fluid (CSF) pathways, the curves after surgery resembled the normal collective. The complete remission of those changes in some patients suggested restoration of near-normal CSF dynamics.

Ultrasound-guided initial diagnosis and follow-up of pediatric idiopathic intracranial hypertension

BACKGROUND

Idiopathic intracranial hypertension in children often presents with non-specific symptoms found in conditions such as hydrocephalus. For definite diagnosis, invasive intracranial pressure measurement is usually required. Ultrasound (US) of the optic nerve sheath diameter provides a non-invasive method to assess intracranial pressure. Transtemporal US allows imaging of the third ventricle and thus assessment for hydrocephalus.

OBJECTIVE

To investigate whether the combination of US optic nerve sheath and third ventricle diameter can be used as a screening tool in pediatric idiopathic intracranial hypertension to indicate elevated intracranial pressure and exclude hydrocephalus as an underlying pathology. Further, to analyze whether both parameters can be used to monitor treatment outcome.

MATERIALS AND METHODS

We prospectively included 36 children with idiopathic intracranial hypertension and 32 controls. Using a 12-Mhz linear transducer and a 1-4-Mhz phased-array transducer, respectively, optic nerve sheath and third ventricle diameters were determined initially and during the course of treatment.

RESULTS

In patients, the mean optic nerve sheath diameter was significantly larger (6.45±0.65 mm, controls: 4.96±0.32 mm) and the mean third ventricle diameter (1.69±0.65 mm, controls: 2.99±1.31 mm) was significantly smaller compared to the control group, P<0.001. Optimal cut-off values were 5.55 mm for the optic nerve sheath and 1.83 mm for the third ventricle diameter.

CONCLUSIONS

The combined use of US optic nerve sheath and third ventricle diameter is an ideal non-invasive screening tool in pediatric idiopathic intracranial hypertension to indicate elevated intracranial pressure while ruling out hydrocephalus. Treatment can effectively be monitored by repeated US, which also reliably indicates relapse.