Tentorial Venous Anatomy: Variation in the Healthy Population

BACKGROUND AND PURPOSE

A new transtentorial venous system consisting of medial, intermediate, and lateral tentorial veins, connecting infra- and supratentorial compartments, was recently shown in 2 cadaver dissections and 2 patient scans. We sought to characterize the venous patterns within the tentorium and their relation to measures of skull development in a cohort of healthy adults.

MATERIALS AND METHODS

We retrospectively reviewed tentorial venous anatomy of the head using CTA/CTV performed for routine care or research purposes in 238 patients. Included studies had adequate contrast opacification of venous structures and a section thickness of ≤2 mm; we excluded cases with space-occupying lesions and vascular pathologies. Tentorial angle, dural sinus configurations, and measures of skull base development were assessed as predictors of tentorial venous anatomy variation via Cramér V association, the binary encoded Pearson correlation, and nearest-point algorithm with the Euclidean distance metric for clustering.

RESULTS

Tentorial vein development was related to the ringed configuration of the tentorial sinuses (P < .005). There were 3 configurations. Groups 1A and 1B (n = 50/238) had ringed configuration, while group 2 did not (n = 188/238). Group 1A (n = 38/50) had a medialized ringed configuration, and group 1B had a lateralized ringed configuration (n = 12/50). Measurements of skull base development were predictive of these groups. The ringed configuration of group 1 was related to the presence of a split confluens, which correlated with a decreased internal auditory canal-petroclival fissure angle. Configuration 1A was related to the degree of petrous apex pneumatization (P value = .010).

CONCLUSIONS

Variations in the transtentorial venous system directly correlate with cranial development.

Tumefactive demyelinating lesions

We studied 21 cases of pathologically confirmed tumefactive demyelinating lesions and reviewed the spectrum of tumefactive demyelinating lesions in the literature. Radiological features and clinical data were reviewed to characterize the lesions as consistent with a known demyelinating disease, most notably multiple sclerosis. Atypical clinical or radiological features (other than tumefaction) were noted. Most lesions were part of a clinical and/or radiological picture consistent with multiple sclerosis. No case strongly suggestive of variants or related diseases, such as Schilder's disease or Balo's concentric sclerosis, were found. There was one case suggestive of acute disseminated encephalomyelitis. Features which help distinguish the lesions from tumour are discussed.

Meningioangiomatosis: clinical, radiologic, and histopathologic correlation

Meningioangiomatosis (MA) is a rare, benign, hamartomatous lesion of the leptomeninges; MA has been considered to be a forme fruste of neurofibromatosis. A review of pathology records for patients with MA who were seen between 1970 and 1989 at the authors' institutions revealed four patients (three male and one female; aged 2.5-21.0 years; mean, 10.8 years) with a history of seizures but without the stigmata or family history of neurofibromatosis. Three patients had undergone either computed tomographic (CT) or magnetic resonance (MR) imaging studies. All patients had undergone craniotomies to obtain tissue for pathologic analysis; a peripheral, leptomeningeal lesion was found in all four patients. At CT in two patients, the lesions were most consistent with calcification. At T2-weighted MR imaging in one patient, the lesion demonstrated a hyperintense periphery with associated edema of the white matter. Histopathologic examination demonstrated characteristic features of MA--cortical meningovascular fibroblastic proliferation and leptomeningeal calcification. The accurate diagnosis of MA is important since MA is a benign, surgically correctable cause of seizures.

The multiloculated renal mass: considerations and differential features

1. Many diverse disease processes may result in a multiloculated renal mass. 2. The term "multilocular cyst" is purely descriptive and should not be used as a specific diagnosis. 3. The management of this diverse group of diseases is controversial. There is insufficient information concerning the accuracy of percutaneous biopsy to permit one to base management decisions on such a biopsy in most of these masses. The cystic diseases (septated cyst, localized cystic disease, segmental multicystic kidney) should be managed conservatively. Most cases of arteriovenous communication are readily diagnosed angiographically and managed by vascular occlusive techniques or by surgery. The remaining multiloculated renal masses usually require surgical removal for histologic diagnosis or definitive therapy or both.