Brain death in the neonate: assessment with P-31 MR spectroscopy.
Explore the source record for details and available documents.
Brain↗
Biomedical subjects
M R Terk
Publications and source records attributed to M R Terk.
Halfscan: clinical applications in MR imaging.
A series of phantom experiments was performed to evaluate the effects of half-Fourier scanning, also known as Halfscan, on signal-to-noise and in-plane resolution. Resolution was not demonstrably effected with the available phantoms and signal-to-noise was seen to vary as the square root of time independent of the implementation of Halfscan. Evaluation of the Halfscan technique was made using data from 240 patients. The technique was found to "salvage" examination in an estimated 70% of uncooperative patients where motion artifact or other patient concerns would have precluded clinically useful studies. Halfscan was also combined with other techniques such as increased number of signal acquisitions, prolonged repetition times and three-dimensional Fourier transform technique.
Artifacts↗
Primary lymphoma of the cervix: MRI findings with gadolinium.
MRI evaluation of primary cervical lymphoma has not been reported. We report such a case of primary cervical lymphoma, a lesion well seen and well delineated from normal tissue by MRI. Although primary lymphoma of the cervix is a rare entity, the disease does exist and can be well demonstrated by MRI. We evaluated the MR appearance of this lesion with both nonenhanced and gadolinium-enhanced imaging.
Adult↗
Magnetic resonance imaging of nasopharyngeal and paranasal sinus melanoma.
Malignant melanoma of the nasopharynx and paranasal sinuses is relatively rare. We retrospectively reviewed the magnetic resonance appearance of five cases and correlated this with the histopathological appearance. In all cases, the magnetic resonance (MR) images clearly demonstrated the precise anatomic extent of the tumor and were sensitive in assessing intracranial extension and invasion into surrounding structures, including the skull base. Three cases were reviewed for histopathological evidence of melanin, hemosiderin, and acute hemorrhage. One case was reviewed for melanin and hemorrhage only. The findings in this series suggest that melanoma of the nasopharynx and paranasal sinuses have extremely variable amounts of paramagnetic substances, both melanin and products of hemorrhage. T1 shortening appears to be more often a reflection of the paramagnetic effects associated with products of hemorrhage rather than the presence of melanin.
Acute Disease↗
MRI of the brachial plexus: a review of 51 cases.
We present a magnetic resonance imaging (MRI) study in 51 patients where the brachial plexus was evaluated. Using a 1.5 T clinical imaging system, we obtained T1-weighted sequences, and double-echo (intermediate- and T2-weighted) spin-echo images. The coronal plane was imaged in all examinations and was supplemented by images in the sagittal and/or axial planes. Twenty cases had proven pathological brachial plexus involvement, whereas, in 31 cases, no brachial plexus involvement was present. In 4 cases, the MRI findings were not in agreement with the final diagnosis found in the charts.
Brachial Plexus↗
The impact on treatment planning of MRI of the spine in patients suspected of vertebral metastasis: an efficacy study.
The objective of this study was to determine the efficacy of spinal MRI in suspected spinal metastasis. The effect of spinal MRI on treatment planning choices (radiation, chemotherapy, steroids, or surgery) in 130 patients with suspected spinal metastatic involvement was evaluated. In a retrospective group of 100 patients, 47 (47%) had therapy changes associated with MR findings. Forty out of 78 (51%) of patients presenting with symptoms (back pain, weakness, paresthesia, or sphincter dysfunction) had MR associated therapy choices. Seven out of 22 (32%) of patients without spinal symptoms had therapy changes. Twelve out of 30 (40%) of patients evaluated prospectively had therapy choices directed by MR findings. Overall, 59 out of 130 (45%) of patients had therapy choices associated with findings in spinal MRI. MRI results influenced the addition or modification of radiation therapy treatment in 33% of the patients suspected of metastatic disease to the spine.
Adult↗
Magnetic resonance angiography in neck masses.
Carotid MR angiography has primarily been used to evaluate for stenotic lesions. We performed 2D time of flight MR angiography in 25 patients with palpable neck masses. There were 23 masses confirmed histologically. Two of the masses represented abnormal carotid arteries. Carotid deviation was seen in 23 of 25 (92%) of patients. Widening of the carotid bifurcation was identified in seven patients, including four carotid body tumors, one inflammatory mass, one benign salivary gland tumor, and one schwannoma. Increased vascularity was identified in one carotid body tumor and in one metastatic papillary carcinoma of the thyroid. MR angiography may be useful to demonstrate flow within vessels and represents a familiar imaging display for surgical planning. Splaying of the carotid bifurcation is useful in demonstrating carotid space lesions.
Adolescent↗
MR findings in patients with acute tibial plateau fractures.
OBJECTIVE: The purpose of this study was to demonstrate the MRI findings associated with acute tibial plateau fractures. MATERIALS AND METHODS: MR scans of 29 patients with acute tibial plateau fractures were analyzed retrospectively. The images were evaluated for the presence of injuries involving the menisci, cruciate and collateral ligaments. The presence of a lipohemarthrosis or a simple joint effusion was also noted. The tibial plateau fractures were classified according to the scheme devised by Schatzker. RESULTS: Evidence of internal derangement of the knee was found in 28 (97%) patients. Tibial collateral ligament (55%) injuries and lateral meniscus (45%) tears were noted most frequently. Medial meniscus tears were seen in 21% and fibular collateral ligament injuries were diagnosed in 34%. Forty-one percent had anterior cruciate ligament injuries while the posterior cruciate ligament was injured in 28%. Twelve (41%) patients demonstrated the characteristic MRI features of a lipohemarthrosis. Simple joint effusions were found in the remaining 17 (59%) patients. CONCLUSION: MR imaging in patients with acute tibial plateau fractures commonly demonstrates associated ligamentous and meniscal injuries. By imaging in multiple planes, MRI can aid in the accurate characterization of tibial plateau fracture patterns and severity.
Adult↗
SPIR MRI in spinal diseases.
We report on our experience with the fat suppression technique of spectral presaturation with inversion recovery MR in imaging certain spinal disorders. This technique may assist in demonstrating or excluding the presence of fat within a lesion (such as lipoma, dermoid, teratoma) or within a normal structure (i.e., vertebral body or epidural space). The method can also be used to suppress normal fat (such as marrow or epidural fat) thus increasing the conspicuity of adjacent high signal intensity lesions seen on T1-weighted images (such as blood and contrast-enhancing tumors or inflammatory lesions).
Abscess↗
Dual oblique MR method for imaging the sciatic nerve.
We present an alternative imaging technique for evaluation of the sacral plexus and sciatic nerve. Images were obtained in the oblique coronal, oblique sagittal, and oblique axial planes using the piriformis muscle as the initial reference point. Evaluation of the sciatic nerve is optimized by the multiplanar capability of MRI.
Adolescent↗
MRI of destructive achilles tendon rupture associated with skin ulceration.
We present a case series of the MR findings of destructive tears of the Achilles tendon secondary to overlying soft tissue ulcerations.
Achilles Tendon↗
The application of magnetic resonance techniques to the evaluation of the patient with sickle-cell disease.
Sickle-cell anemia presents unique challenges to the clinician who wishes to obtain important data regarding anatomic lesions and metabolic states without subjecting the patient to additional risks involving the imaging techniques. Two applications-magnetic resonance angiography and magnetic resonance spectroscopy-are described in this review.
Anemia, Sickle Cell↗
Magnetic resonance imaging applications to cardiac diagnosis.
Applications of MRI to cardiac diagnosis have improved and expanded. Thus, while MRI was initially useful for demonstrating cardiac anatomy, congenital malformations, thrombi, and masses, current techniques can demonstrate cardiac function, including evaluation of valvular disease and cardiac shunts along with cardiac flow quantitation. Further refinements have led to the demonstration of coronary artery anatomy. In the future, a comprehensive cardiovascular evaluation may be available with MRI.
Cardiac Output↗
Method for assessing cardiac function using magnetic resonance imaging.
The authors sought to define a method to use magnetic resonance (MR) to assess cardiac function by obtaining short-axis images of the left ventricle (LV) in humans. Sagittal and axial scout1H MR images were used in the protocol. The long axis of the LV was defined in both planes using the mitral valve and left ventricular apex as references. Based on this double angulation, the acquisition planes were created for a series of parallel short-axis images extending from the base to the apex of the left ventricular cavity. Cardiac images acquired with a fast-field echo technique, six slices with 16-20 phases per RR interval, were analyzed, representing the initial 75-80% of the cardiac cycle. For each slice, the endocardial border of the left ventricular chamber was manually traced. Using Simpson's rule, the total LV volume at a given phase was determined, considering the traced area, thickness, and position in three-dimensional space of each of the six constituent slices. The calculated volumes were plotted against time, and the stroke volume, ejection fraction, and cardiac output were determined. These parameters are clinically significant indices of cardiac function. Accurate and useful estimates of LV function can be obtained using MRI according to this protocol.
Cardiac Output↗