Nongated cardiac magnetic resonance imaging: preliminary experience at 0.12 T.

Nongated cardiac magnetic resonance imaging (MRI) has been reported previously to be inadequate for obtaining diagnostic information. This study explored the role of pulse sequence in the degradation of the nongated cardiac image. Images of diagnostic quality were obtained by using single spin-echo sequences with a very short echo time (10-20 msec TE) on a 0.

Potential problems with selective pulses in NMR imaging systems.

Most nuclear magnetic resonance (NMR) imaging systems require pulses whose frequency spectrum is shaped so as to selectively excite a given plane in the presence of a magnetic field gradient. We demonstrate by both computer simulation and experiment that linear Fourier transform theory is not a reliable guide to the uniformity of flip angle in the slice. We show by simulation that the nonuniformity can have serious implications for the measurement of relaxation time T1 if selective 180 degrees pulses are used; the exact results depend also on the details of data analysis and criteria for adjusting the rephasing gradients.

Nuclear magnetic resonance imaging in gynecology.

Nuclear magnetic resonance proton imaging is a new imaging technique that holds promise for gynecologic diagnosis. Without the use of ionizing radiation, it provides images with excellent definition of the major pelvic organs. The extent and nature of disease are well demonstrated.

Focal renal masses: magnetic resonance imaging.

Thirty patients with focal renal masses were evaluated on a .12-Tesla resistive magnetic resonance unit using partial saturation and spin echo pulse sequences. A short repetition time (TR = 143 ms) was employed for partial saturation images and a spin echo was present in each case (TE = 10 ms).

MR imaging of the mediastinum: a retrospective comparison with computed tomography.

Magnetic resonance (MR) imaging of the mediastinum was performed with a 0.12 T resistive magnet and compared with the results of CT. On T1 weighted images with partial saturation technique, soft tissue masses, lymphadenopathy, lipomatosis, and vascular anatomy were comparable with MR and CT imaging in 19 of 30 patients (63.

Surface coil magnetic resonance imaging.

A surface coil is used as a receiver in a crossed-coil arrangement with a conventional circumferential transmitter coil in a magnetic resonance imaging system. The improved signal-to-noise ratio for objects close to the coil, compared with a conventional circumferential saddle-shaped receiver coil, permits higher resolution imaging of relatively superficial structures such as the orbit, neck, chest wall, and lumbar spine.

Osteomalacia and osteitis fibrosa in a man ingesting aluminum hydroxide antacid.

A 53-year-old man with a history of long-term aluminum hydroxide antacid ingestion reported diffuse bone pain and multiple stress fractures over a two-year period. An undecalcified transiliac bone biopsy specimen revealed osteomalacia with osteitis fibrosa; plasma parathyroid hormone and cyclic AMP levels were normal. Following withdrawal of antacids and treatment with calcium and phosphorus, an initially elevated plasma, 1,25-dihydroxyvitamin D level fell to within the normal range, accompanied by decreased bone pain, healed stress fractures, and increased axial bone mineral content as determined by computed tomography of lumbar trabecular bone.

Orientation of magnetic resonance images.

The author reports on the recommendations of the ACR Subcommittee on MR Terminology regarding the orientation of MR images.

Coronal nuclear magnetic resonance (NMR) imaging of the abdomen at 0.5 tesla.

Coronal nuclear magnetic resonance (NMR) abdominal imaging was performed on a normal volunteer. The scan technique and anatomic features are described. Coronal abdominal scanning optimizes vascular imaging in the abdomen and is helpful in defining the anatomic relationships of a variety of structures.

Relaxation times and NMR signals.

The strength of signals in magnetic resonance imaging (and the resulting image contrast) depends not just on the number density of the nuclei being detected, but also on the relaxation times, T1 and T2. The relationship of signal strength to relaxation time depends on the particular choice of pulse sequences used to produce the signals. The effects of the T1 relaxation time on signal strength are discussed for the commonly used imaging techniques "partial saturation" and "inversion recovery.

Functional imaging of the liver. New information from dynamic CT.

In order to assess their potential usefulness in conjunction with dynamic CT scans of the liver, functional images of several variables related to blood flow were created from dynamic CT scans of 15 patients with a variety of liver diseases. Seven of the patients received intra-arterial and intravenous boluses of contrast; the other eight received intravenous boluses alone. Intra-arterial contrast injections yielded superior functional images, but useful functional images could also be created from studies with intravenous boluses.

NMR imaging of the abdomen at 0.12 T: initial clinical experience with a resistive magnet.

Forty-five patients with a variety of abdominal abnormalities and five normal volunteers were imaged on a 0.12 T resistive nuclear magnetic resonance system. Scans were obtained with saturation-recovery technique and short repetition times.

NMR imaging of the chest at 0.12 T: initial clinical experience with a resistive magnet.

The chests of 40 subjects were imaged with an experimental nuclear magnetic resonance (NMR) imager operating at a magnetic field of 0.12 T. There were six normal volunteers and 34 patients with abnormalities affecting different areas, including the chest wall, pleura, hila, mediastinum, and lung parenchyma, and including benign and malignant processes.

The role of single and double-contrast radiography in the diagnosis of reflux esophagitis.

Sixty-seven patients with endoscopically proved esophagitis and 25 patients who had no esophageal disease were examined by double-contrast esophagography, followed by a single-contrast examination. The radiographs were evaluated separately and as a combined examination technique by three independent radiologists in a blind analysis. The respective sensitivities were 77% for the single-contrast examination, 80% for the double-contrast examination, and 88% for the combined examination method with no significant statistical difference (P = 0.

Three-dimensional display of nuclear magnetic resonance (NMR) cardiovascular images.

A set of contiguous nuclear magnetic resonance images of the thorax of a living dog was used to create various types of three-dimensional display of the myocardium and great vessels. These structures can be displayed separately or together as transparent or opaque surfaces and can be shown as rotating three-dimensional figures.