C. Leon Partain

Preoperative assessment of myometrial invasion of endometrial adenocarcinoma by sonography (US) and magnetic resonance imaging (MRI)

The presence and/or depth of myometrial invasion of endometrial adenocarcinoma has important prognostic and therapeutic implications. Fifteen patients with histologically proven endometrial cancer underwent preoperative evaluation with sonography (US) and magnetic resonance imaging (MRI) to assess depth of invasion. Using criteria of greater than or equal to 50% of myometrial wall involvement as representing deep invasion, and less than 50% as superficial invasion, US was more accurate than MRI in five cases; in three MRI was more accurate than US; both MRI and US were equally accurate in four; neither was accurate in three. Polypoid lesions caused the greatest number of false positive reports of deep invasion with both MRI and US. Preliminary results indicate that US and MRI have promise as preoperative tests to assess the extent of myometrial invasion.

Magnetic resonance imaging of the breast: Functional T1 and three-dimensional imaging

Thirty-two patients with breast abnormalities and 10 normal volunteers were examined with magnetic resonance imaging (MRI) utilizing a 0.5-Tesla superconducting magnet imaging system. Sagittal, coronal, and transverse breast imaging with the 50-cm body coil and with a specialized 16×8 cm breast coil allowed the evaluation of a single breast. Soft-tissue contrast was clearly apparent using proton density-weighted. T1 weighted, calculated T1 images. In addition, the feasibility and potential clinical utility of three-dimensional color imaging was evaluated using computer-based interactive algorithms for edge detection of the breast and for abnormal structures within the breast. MR scan data were correlated with conventional xeromammography, ultrasound, clinical, data, and pathological specimens. In vivo and in vitro breast imaging was evaluated in a feasibility study. It was concluded that MR imaging is a most sensitive modality for the identification of breast lesions, especially when the adjacent normal tissue is primarily fat. There does appear to be significant overlap in soft-tissue contrast when the adjacent breast parenchymal tissue is fibrocystic in nature. The T1 parameter may be a relatively specific measure for identifying a malignant breast mass.

Gated magnetic resonance imaging of acute myocardial ischemia in dogs: Application of multiecho techniques and contrast enhancement with Gd DTPA

ECG gated magnetic resonance images were obtained in six canines prior to and immediately following occlusion of either the LAD or circumflex coronary artery using a surgically placed snare. Multiecho and single-echo acquisition techniques were utilized 0.25 mmol/kg Gd DTPA was injected as an IV bolus 1 hr following coronary artery ligation. In two animals, the region of ischemic myocardium was clearly visualized on multiecho technique without the use of intravenous contrast. The ischemic zone could be best identified on images with a long TE of 120 msec. Contrast enhancement with Gd DTPA enabled visualization of the ischemic myocardium in all six canines. Administration of Gd DTPA, a perfusion agent, improved both detectability and definition of the myocardial lesions.

Primary glioma: diagnosis with magnetic resonance imaging

Seventeen patients with surgically documented primary glial-origin brain tumors were evaluated by magnetic resonance imaging and high-resolution computed tomography. The exclusion of CT ring-enhancing lesions directed the focus of this study toward lower grade tumors that were more difficult to diagnose. The computed tomography abnormalities were often subtle and included areas of low attenuation, mass effect, and focal enhancement. Spin-echo sequences with both heavy T1 and T2 weighting were utilized. Prolonged T1 and T2 values were observed in all tumors. The T2-weighted spin-echo 1000/120 sequence was the most sensitive in tumor detection and was positive in all cases. Magnetic resonance imaging was superior to computed tomography in tumor detection, tumor localization, assessment of tumor extent, and determination of associated changes, ie, brain stem encroachment. All the magnetic resonance sequences used showed an increase in severity of imaging changes with increasing tumor grade. The T2-weighted sequence showed progressive margin irregularity, whereas the T1-weighted (inversion recovery) sequence showed increasing severity of internal tissue changes. The superior resolution of these changes by magnetic resonance imaging may have implications for better assessment of tumor grade in the future than is currently possible with computed tomography.

Clinical Impact of Picture Archiving and Communication Systems: Evaluation of a Prototype System

Opinion surveys were gathered before and 6 months after installation of a prototype picture archiving and communication system (PACS) (PACS/1, Siemens Medical Systems, Iselin, NJ). Median turnaround times and the percent of delayed or missing reports were calculated for 1,026 baseline and 8,438 follow-up studies at 6 months. Neuroradiological (neuro) computed tomography (CT) used PACS, while neuro magnetic resonance (MR), body CT, and body MR served as controls. The opinion surveys showed improved service in all categories, including those not directly affected by PACS. PACS images favorably impressed 86% of respondents, but most considered the system too slow, unreliable, and the storage capacity too low. A majority of 81% recommended against purchase of PACS now. There was an overall increase in the median report turnaround time for both neuro CT and the controls. Neuro CT showed a 41% decrease in delayed or missing reports, but controls also showed similar decreases. The effects of this prototype PACS on turnaround time or on report delivery could not be distinguished from section-wide changes in CT and MR services. Future improvements in PACS should vigorously address increased speed, reliability, and storage capacity.

Techniques of non-orthogonal magnetic resonance imaging and its clinical application

A technique to obtain non-orthogonal magnetic resonance (MR) images in the body has been developed using a simple three-dimensional model (3-DM). Images were obtained with multiple non-orthogonal planes, without subjecting patients to uncomfortable oblique positions. Eighty-two patients were studied using non-orthogonal planes. Euler angle determinations (EAD) were developed for different anatomical locations as well as for multiple clinical situations. One or all three Euler angles were changed using the EAD to define any plane of orientation relative to reference orthogonal frame. In a series of 12 patients for postoperative evaluation of Mustard and Senning procedure, the demonstration of anastomotic site was superior with angled coronal planes when compared to the routine coronal views in 83% of the studies. With the use of EAD, acquisition time for non-orthogonal planes can be reduced. 3-DM aids in the understanding of the Euler angles and leads to multiple non-orthogonal planes.

Nuclear Magnetic Resonance (NMR) Imaging: Potential Impact On Medical Diagnosis And Digital Data Communications

Nuclear magnetic resonance is a phenomenon which allows the generation of high quality medical images including the traditional transverse, coronal, and sagittal perspectives, while utilizing no ionizing radiation and without any known adverse biological effect. In addition, NNR imaging and diagnostic techniques allow the generation of basic chemical/pathophysiological measurements which have great promise to enhance the accuracy of medical diagnosis by providing more specific diagnostic information.