Biomedical subjects
Publications and source records attributed to K Koral.
We present a case of extracranial craniopharyngioma simulating a sphenoid sinus mucocele in a 12-year-old female who presented with progressive subacute left-sided visual disturbance. Although infrasellar craniopharyngioma is a rare entity, the presence of foci of calcification within the lesion is a useful finding for diagnosis.
Basal encephaloceles are the least common form of encephalocele. Due to the critical position of the bony defect, visual and endocrinological abnormalities are frequently associated with basal encephaloceles. There is significant confusion in the classification of basal encephaloceles, particularly among trans-sphenoidal, sphenoethmoidal and intrasphenoidal subtypes. Two cases of basal encephaloceles are presented (one trans-sphenoidal and one sphenoethmoidal), along with a review of the literature. The relationship between the basal encephaloceles and endocrinological abnormalities is also emphasized.
We report on a rare case of desmoid tumor in a 40-year-old man with low back pain and cough. There was no history of previous surgery or trauma. MR imaging revealed a posterior mediastinal mass extending into the abdominal cavity.
This paper applies and evaluates an automatic mutual information-based registration algorithm across a broad spectrum of multimodal volume data sets. The algorithm requires little or no pre-processing, minimal user input and easily implements either affine, i.e. linear or thin-plate spline (TPS) warped registrations. We have evaluated the algorithm in phantom studies as well as in selected cases where few other algorithms could perform as well, if at all, to demonstrate the value of this new method. Pairs of multimodal gray-scale volume data sets were registered by iteratively changing registration parameters to maximize mutual information. Quantitative registration errors were assessed in registrations of a thorax phantom using PET/CT and in the National Library of Medicine's Visible Male using MRI T2-/T1-weighted acquisitions. Registrations of diverse clinical data sets were demonstrated including rotate-translate mapping of PET/MRI brain scans with significant missing data, full affine mapping of thoracic PET/CT and rotate-translate mapping of abdominal SPECT/CT. A five-point thin-plate spline (TPS) warped registration of thoracic PET/CT is also demonstrated. The registration algorithm converged in times ranging between 3.5 and 31 min for affine clinical registrations and 57 min for TPS warping. Mean error vector lengths for rotate-translate registrations were measured to be subvoxel in phantoms. More importantly the rotate-translate algorithm performs well even with missing data. The demonstrated clinical fusions are qualitatively excellent at all levels. We conclude that such automatic, rapid, robust algorithms significantly increase the likelihood that multimodality registrations will be routinely used to aid clinical diagnoses and post-therapeutic assessment in the near future.
This study aimed to determine the inherent error of the left ventricular volume measurement from the gated equilibrium blood pool scintigram utilizing the count-based technique. The study population consisted of 26 patients who had undergone biplane contrast ventriculography. The patients were imaged with a parallel-hole collimator in the left anterior oblique position showing the septum to best advantage. A reference blood sample was counted and radionuclide volumes calculated without correction for attenuation. Attenuation corrected volumes were derived with the factor 1/e-mud, where d = distance from skin marker to center of the left ventricle in the orthogonal left posterior oblique view and mu = linear attenuation coefficient. A series of mu values from 0.08 to 0.15 cm-1 was evaluated. There was a trend toward improvement in the r value and lowering of the SEE with attenuation correction. The tightest 95% confidence limits achieved for an end-diastolic 150-ml ventricle were +/- 44 ml, and for an end-systolic 75-ml ventricle +/- 32 ml. In view of the magnitude of inherent error, the count-based volume measurement may be more suitable for group analyses and in cases in which an individual patient serves as his own control.
Invasive pulmonary aspergillosis (IPA) is usually a condition of the immunocompromised patients. The organism has a tendency to invade pulmonary blood vessels. Extension of a pulmonary parenchymal lesion to involve the mediastinal great vessels is very rare. This is the first case where the extension of IPA to the aortic arch and the formation of a pseudoaneurysm were demonstrated on serial CT scans.