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Background: Bochdalek's flower basket (Bfb) is the distal part of the horizontal segment of the fourth ventricle's choroid plexus protruding through the lateral aperture (foramen of Luschka). The microsurgical anatomy of the cerebellopontine angle, fourth ventricle and its inner choroid plexus is well described in the literature, but only one radiological study has investigated the Bfb so far. The goal of the present study was to give an extensive morphometric analysis of the Bfb for the first time and discuss the surgically relevant anatomical aspects. Method: Forty-two formalin-fixed human brains (84 cerebellopontine angles) were involved in this study. Photomicrographs with scale bars were taken in every step of dissection to perform further measurements with Fiji software. The lengths and widths of the Bfb, rhomboid lip and lateral aperture of the fourth ventricle as well as the related neurovascular and arachnoid structures were measured. The areas of two sides were compared with paired t-tests using R software. Significance level was set at p < 0.05. Results: Protruding choroid plexus was present in 77 cases (91.66%). In 6 cases (7.14%), the Bfb was totally covered by the rhomboid lip, and in one case (1.19%), it was absent. The mean width of the Bfb was 6.618 mm (2-14 mm), the mean height 5.658 mm (1.5-14 mm) and mean area 25.80 mm (3.07-109.83 mm). There was no statistically significant difference between the two sides ( p = 0.1744). The Bfb was in contact with 20 AICAs (23.80%), 6 PICAs (7.14%) and 39 vestibulocochlear nerves (46.42%). Arachnoid trabecules, connecting the lower cranial nerves to the Bfb or rhomboid lip, were found in 57 cases (67.85%). Conclusions: The Bfb is an important landmark during various surgical procedures. Detailed morphology, dimensions and relations to the surrounding neurovascular structures are described in this study. These data are essential for surgeons operating in this region. [ABSTRACT FROM AUTHOR]

Standard magnetic resonance imaging (MRI) does not depict the true extent of tumour cell invasion in gliomas. We investigated the feasibility of advanced imaging methods, i.e. diffusion tensor imaging (DTI), fibre tracking and O-(2-[18F]-fluoroethyl)- L-tyrosine (18F-FET) PET, for the detection of tumour invasion into white matter structures not visible in routine MRI. DTI and fibre tracking was performed on ten patients with gliomas, WHO grades II-IV. Five patients experienced preoperative sensorimotor deficits. The ratio of fractional anisotropy (FA) between the ipsilateral and contralateral pyramidal tract was calculated. Twenty-one stereotactic biopsies from five patients were histopathologically evaluated for the absolute numbers and percentages of tumour cells. 18F-FET PET scans were performed and the bilateral ratio [ipsilateral-to-contralateral ratio (ICR)] of 18F-FET-uptake was calculated for both cross-sections of pyramidal tracts and biopsy sites. The FA ratio within the pyramidal tract was lower in patients with sensorimotor deficits (0.61–1.06) compared with the FA ratio in patients without sensorimotor deficits (0.92–1.06). In patients with preoperative sensorimotor deficits, we found a significantly ( p = 0.028) higher ICR of 18F-FET uptake (1.01–1.59) than in patients without any deficits (0.96–1.08). The ICR of 18F-FET-uptake showed a strong correlation ( r = 0.696, p = 0.001) with the absolute number of tumour cells and a moderate correlation ( r = 0.535, p = 0.012) with the percentage of tumour cells. Our data show an association between preoperative sensorimotor deficits, increased 18F-FET uptake and decreased FA ratio in the pyramidal tract. We demonstrated a correlation between tumour invasion and 18F-FET uptake. These findings may help to distinguish between edema versus tumour-associated neurological deficits and could prevent the destruction of important structures, like the pyramidal tract, during tumour operations by allowing more precise preoperative planning. [ABSTRACT FROM AUTHOR]

A letter to the editor is presented in response to an article on peripheral trigemino-cardiac reflex that was published in the May 26, 2009 issue.