Biomedical subjects
Publications and source records attributed to R Kier.
At the sites of previously documented lung metastases from bladder carcinoma, computed tomography identified lung cavities that were virtually imperceptible by plain radiographs. Such thin-walled cavities, which developed following chemotherapy, have not been previously described in patients with bladder carcinoma.
A case of malignant teratoma of the thyroid gland is presented. Computed tomography identified an inhomogeneous mass with dense calcifications involving the thyroid gland and compressing the upper airway. Enlarged, peripherally enhancing lymph nodes in the neck and mediastinum suggested its malignant etiology.
In patients with severe renal insufficiency, the high iodine doses used for intravenous contrast medium enhanced CT can lead to renal injury. To minimize renal toxicity in one such patient, dynamic contrast enhanced CT was performed during right common carotid arterial infusion of 17 ml of 30% diatrizoate meglumine solution. Intense homogeneous contrast enhancement of an otherwise isodense mass permitted a diagnosis of meningioma, with excellent definition of tumor extent.
The use of magnetic resonance (MR) to preoperatively evaluate patients with primary hyperparathyroidism was assessed using a 1.5 T system and surface coil reception. Twenty-five patients with primary hyperparathyroidism were studied before surgical exploration. Axial images, 5 mm thick, were obtained from the thyroid cartilage to the sternal notch. Both T1-weighted [short repetition time (TR), short echo time (TE)] and T2-weighted (long TR, long TE) spin echo sequences were performed in most cases. Parathyroid adenomas typically demonstrated greater signal than surrounding tissues on T2-weighted sequences, yet demonstrated signal intensity that was less than or equal to normal thyroid tissue on T1-weighted sequences. Using these criteria, MR correctly identified 17 of 20 surgically proven parathyroid adenomas in the neck. Magnetic resonance appeared less sensitive in two patients with parathyroid hyperplasia, identifying only one of six hyperplastic glands. We conclude that MR with surface coils provides high contrast, anatomic delineation of the neck and is useful for preoperative localization of parathyroid tumors.
Two patients with sports-related knee injuries underwent magnetic resonance (MR) imaging, which demonstrated intracapsular fractures and effusions with a signal pattern characteristic of lipohemarthrosis. Four distinct signal bands were identified: superior band representing floating fat, a central band containing serum, an inferior band of dependent red blood cells, and a thin band representing chemical shift artifact at the interface of serum and floating fat.
The 10 major ligaments and nine major tendons of the ankle were evaluated in 17 ankle MR studies to determine the incidence of visualization of each structure in each of the three orthogonal planes. High-resolution technique was used, with 3 mm slice thickness and an in-plane resolution of 0.6 mm. Of the 19 ligaments and tendons evaluated, 18 demonstrated more than 70% frequency of visualization in at least one imaging plane. However, seven ligaments and three tendons demonstrated 0% visualization in at least one of the three orthogonal planes. Seven ligaments showed more than 70% visualization in only one plane (three coronal, two axial, two sagittal). Only the Achilles tendon and anterior tibial tendon demonstrated 100% visualization in all three planes. We conclude that all three orthogonal planes are essential to achieve optimal visualization of all of the major ligaments and tendons of the ankle. For specific evaluation of selected ligaments or tendons, only one or two planes may be required.
We compared the ability of MRI and CT to detect and characterize abdominal visceral injury. Seven patients with contrast-enhanced abdominal CT interpreted as showing definite (five patients) or possible (two) solid organ injury following blunt abdominal trauma were referred for abdominal MRI with a mean interval of 3 days between modalities. T1-weighted and T2-weighted spin echo sequences were obtained in all patients. Gradient-recalled echo (GRE) sequences (22-25/12-13/60 degrees flip angle) were obtained in five cases. Both CT and MR allowed detection of complex splenic lacerations in two patients and complex hepatic injuries in three other patients. A sixth patient had subtle periportal hypodensity noted on CT which was not detected prospectively on MRI. One patient had a right adrenal hematoma detected on MRI but not on CT. Relative lesion conspicuity and extent were judged equal on CT and T2-weighted imaging. The T1-weighted and GRE imaging were judged inferior to CT. We conclude that MRI offers no significant advantage over CT for the routine evaluation of acute abdominal trauma.