PubMed Health⌕ Search

Biomedical subjects

D N Richardson

Publications and source records attributed to D N Richardson.

6 recordsLinked to original sources
PubMed1991

Focal high signal on MR scans of the midbrain caused by enlarged perivascular spaces: MR-pathologic correlation.

Punctate and linear foci of abnormal signal were observed near the substantia nigra in the midbrains of 32 (20%) of 157 patients undergoing high-resolution MR imaging of the brainstem. The lesions were most easily seen on long TR/long TE images, where they were of high signal intensity. Their location was consistently in the lower mesencephalon near the junction of the substantia nigra and cerebral peduncle. Unilateral lesions were observed in 18 cases, while bilateral lesions were noted in 14. A review of anatomic specimens revealed the constant presence of penetrating branches of the collicular or accessory collicular arteries in this location. Enlarged perivascular spaces around these vessels were frequently seen in the specimens and probably account for punctate and linear foci observed on high-resolution MR images of the midbrain.

Adult↗
PubMed1989

Meningiomas: MR and histopathologic features.

The magnetic resonance (MR) appearances of 40 biopsy-proved meningiomas were blindly evaluated and correlated with their predominant histologic pattern--fibroblastic, transitional, syncytial, angioblastic, or mixed. T1-weighted images were not particularly useful in discriminating pathologic subtype, because most tumors were isointense with or hypointense to cortex regardless of histologic type. Signal intensity and features on T2-weighted images strongly correlated with histopathologic findings in over 75% of cases, however. Meningiomas markedly hypointense to cortex on T2-weighted images (seven of 40 cases) were composed predominantly of fibroblastic or transitional elements, while markedly hyperintense meningiomas (14 of 40 cases) demonstrated predominance of syncytial or angioblastic elements. Consideration of secondary features visible at MR imaging (degree of edema, cyst formation, presence of calcium aggregates) led to a more specific histologic prediction in over half of the remaining isointense tumors. The varied MR appearance of meningiomas has a clear histologic basis, and crude prediction of pathologic subtype is possible in over three-fourths of cases.

Brain Neoplasms↗
PubMed1988

The history of Nolvadex.

The research programme leading to the discovery of Nolvadex (tamoxifen, ICI 46474) (2; R1 = Me, X = Et), the anti-oestrogen used widely in the treatment of breast cancer, is described by the chemist involved in the discovery.

Animals↗
PubMedDate not supplied

Dilated intercavernous sinuses: an MR sign of carotid-cavernous and carotid-dural fistulas.

Dilated venous channels traversing the sella and connecting the two cavernous sinuses were seen on contrast-enhanced MR images in four patients with angiographically proved carotid fistulas. The anatomy and variations of these so-called intercavernous sinuses are discussed and are demonstrated in Latex-injected anatomic specimens. Direct visualization of the intercavernous sinuses on contrast-enhanced MR images may serve as an ancillary sign for the diagnosis of carotid-cavernous or carotid-dural fistulas near the sella.

Adult↗