Intraparenchymal ventricular diverticula in chronic obstructive hydrocephalus: prevalence, imaging features and evolution.

BACKGROUND: Intraparenchymal cavities communicating with the ventricles may appear in patients with chronic obstructive hydrocephalus despite no identifiable surgerical, vascular or traumatic causes. The rate, features, pathogenesis, evolution and clinical impact of intraparenchymal diverticula have not been outlined, yet. METHODS: Brain MRIs of 130 patients (mean age: 11.3 years; age range: 0-67; 60 females) with chronic obstructive hydrocephalus were analyzed. The pathogenesis, neurosurgical treatment, ventricle size, signs of transependymal reabsorption and septum pellucidum integrity of the hydrocephalus were recorded. Subarachnoid outpouching of the ventricles, post-hemorrhagic parenchymal cavities, paths of ventricular shunting and cavities not communicating with the ventricles were excluded. Of patients with intraparenchymal diverticula, all previous available CT and MRI scans were evaluated. RESULTS: Eight patients (6.2 %, mean age: 18.7 years; age range: 2-42) harbored 11 intraparenchymal diverticula sprouting from the temporal (6), occipital (3) or frontal (2) horns of the lateral ventricles. Intraparenchymal diverticula were more frequent in males (p = 0.04) and older patients (18.7 ± 12.7 vs 11.3 ± 9.8 years, p = 0.04). Their presence or evolution (mean neuroradiological follow-up 3.6 years; range: 0-8) showed a trend of association with hydrocephalus severity (bifrontal index) and did not correlate with the surgical treatment. In three patients the diverticula progressed during follow-up. One patient presented with hemiparesis consistent with the intraparenchymal lesion and improved after ventricular shunting. A DTI study revealed that the cortico-spinal tract was partly included in the septum between the ventricle and the intraparenchymal diverticulum. CONCLUSIONS: Clinicians dealing with chronic severe obstructive hydrocephalus should be aware of ventricular intraparenchymal diverticulation. Studies aiming at clarifying their pathogenesis and proper management are warranted.

Herniation of cerebellar tonsils in acromegaly: prevalence, pathogenesis and clinical impact.

Herniation of cerebellar tonsils (CTH) might occur in acromegaly patients and improve after acromegaly treatment. Our study investigated CTH prevalence in acromegaly, its relationship with clinical, laboratory and neuroimaging findings and its possible pathogenesis and clinical impact. 150 acromegaly patients (median-age 56 years, age-range 21-88, 83 females) underwent brain magnetic resonance imaging (MRI). Clinical data, laboratory and pituitary adenoma imaging findings were recorded. CTH, posterior cranial fossa area, tentorial angle, clivus, supraocciput and Twining's line length were measured in acromegaly patients and controls, who included MRI of 115 consecutive subjects with headache or transient neurological deficits (control group-1) and 24 symptomatic classic Chiari 1 malformation patients (control group-2). Acromegaly patients were interviewed for symptoms known to be related with CTH. 22/150 acromegaly patients (15 %) and 8/115 control group-1 subjects presented with CTH (p = 0.04). In acromegaly patients, CTH correlated positively with younger age and inversely with GH-receptor antagonist treatment. Control group-2 had a shorter clivus than CTH acromegaly patients (40.4 ± 3.2 mm vs 42.5 ± 3.3 mm, p < 0.05), while posterior fossa measures did not differ among acromegaly subgroups (with and without CTH) and control group-1. Headache and vision problems were more frequent in CTH acromegaly patients (p < 0.05); two acromegaly patients presented with imaging and neurological signs of syringomyelia. Despite no signs of posterior fossa underdevelopment or cranial constriction, CTH is more frequent in acromegaly patients and seems to contribute to some disabling neurological symptoms.