Wilfrido M. Sy

Protracted Yet Variable Major Pulmonary Artery Compression in Sarcoidosis

A case of thoracic sarcoidosis showing diffuse mediastinal lymphadenopathy was followed for a 6-month period with serial chest radiographs, perfusion lung scans, and pulmonary angiograms. Significant extrinsic pressure upon major pulmonary arteries from large lymph nodes of sarcoidosis was seen to cause marked restriction in pulmonary parenchymal perfusion on both scanning and angiography.

Scintigraphic features of superior vena caval obstruction due to substernal non-toxic goitre

Four men with clinical features of superior vena caval syndrome due to large substernal non-toxic multinodular goitre have undergone radionuclide superior vena caval studies. In all cases the dynamic scintigraphs showed a characteristic thyroidal configuration attributed to the definition of stretched thyroidal veins and their tributaries. Radiocontrast studies of two patients demonstrated the characteristic thyroid configuration. A radionuclide superior venacavogram taken post-thyroid lobectomy in one case showed the features had reverted to normal.

Collateral pathways in superior vena caval obstruction as seen on gamma images

The collateral pathways, known from contrast studies to take over the drainage of blood from the various parts of the body when the superior vena cava or its major tributaries are occluded because of disease, can easily be demonstrated with equal clarity (except for the vertebral plexus pathway) by radionuclides. The failure to delineate the vertebral plexus pathway is felt to lie in the close anatomical relationship between the vertebral plexus and the vertebrae, which cause attenuation of the emerging photons. Because of the existing anastomotic channels and their anatomical direction, location and distribution of the individual collateral pathways are individually identifiable. The site/level, extent, degree, and probable duration of occlusion directly affect the degree and extent of the collaterals that subsequently develop. In 20 of 49 abnormal radionuclide superior venacavograms, incidental but abnormal imaging features not ascribable to caval obstruction or syndrome were noted. These included persistent left superior vena cava, aortic aneurysm, pericardial effusion, and disparity in pulmonary perfusion.

Rim and "Doughnut" Signs, and Variants: Review and Reappraisal

The “rim” and doughnut” signs on brain imaging are reappraised. The two signs are distinct, distinguishable and imply diagnostic significance above what is generally realized. The “rim” sign is more commonly associated with subdural and epidural collections, while the “doughnut” sign is indicative of more spherical intracerebral lesions such as tumors, hematomas, abscesses or infarcts. Twelve additional cases resulting from various cerebral disease manifesting either of the two signs or their variants are presented. Examples of the variants of each sign are given and discussed.