Present clinical status of magnetic resonance imaging.

Magnetic resonance imaging has achieved clinical importance and has become the primary tool in the investigation of head, spinal cord, pelvis, cancellous bone, pericardium (with gating), gallbladder, lymph node masses, and very soon, in the evaluation of joints. In many areas, particularly with respiratory and ECG gating, this method promises to replace all other imaging modalities with the precision of information obtained. Today the exceptions are the alimentary tube and its mesentery, between the esophagus and rectum, and the peripheral lung.

Radiologists and informed-consent lawsuits.

A national survey on informed-consent lawsuits that resulted from studies using contrast material revealed that 123 (8%) of 1,513 radiologists surveyed or others in their groups had been involved in informed-consent lawsuits. In response to a detailed follow-up questionnaire, 67 radiologists anonymously provided additional information regarding their lawsuits, which most often involved excretory urography (37%) or angiography (38%), with death or neurologic impairment the most common patient injuries. As a result of these lawsuits, many radiologists provide more detailed information to patients.

Magnetic resonance imaging: absence of in vitro cytogenetic damage.

Human lymphocytes and Chinese hamster ovary (CHO) cells in culture were exposed for 12 1/2 hours to a magnetic resonance imaging apparatus with a 2.35-Tesla magnet and 100-MHz radio frequency emission. The cells were examined for cytogenetic damage manifested either as chromosome aberrations or sister chromatid exchanges (SCEs), which constitute very sensitive measures of genetic and cellular damage.

Diverging gastro-esophageal folds: an useful sign for detecting small hiatal hernias in the erect position.

Upright, double contrast films of the gastro-esophageal junction were reviewed in 30 patients with hiatal hernias and 30 normal controls. Patients with hiatal hernias demonstrated gastro-esophageal folds that converged above the diaphragm and diverged at or beneath the diaphragm on double contrast films of the esophagus. In the normal situation these folds were found to converge at or beneath the diaphragm.

Informed consent for intravenous contrast-enhanced radiography: a national survey of practice and opinion.

A detailed questionnaire regarding the obtaining of patient consent for the administration of intravenous contrast agents was sent to 3845 radiologists in those hospitals across the United States having more than 100 beds. The results represent the current community practice and opinion of the 1547 radiologists (40%) who answered. They showed that 66% of respondents obtained no type of informed consent before injecting intravenous contrast agents.

Gastrointestinal Kaposi's sarcoma in AIDS: radiographic manifestations.

About one-third of all patients with the acquired immunodeficiency syndrome (AIDS) have Kaposi's sarcoma. Gastrointestinal involvement has been noted in 50% of homosexual men with cutaneous Kaposi's sarcoma and AIDS. We report the abnormalities on barium studies of nine homosexual men from the San Francisco bay area who have AIDS and documented gastrointestinal Kaposi's sarcoma.

The clinical role of magnetic resonance imaging.

The development of magnetic resonance imaging ( MRI ) is in an exponential phase and holds unbelievably exciting possibilities for the future of diagnostic medicine. It has many advantages and very few disadvantages compared to other imaging modalities. MRI is rapidly becoming the preferred method for the study of most organs.

Barrett Esophagus.

The authors take a conservative stand on the relationship of Barrett esophagus to adenocarcinoma of the esophagus. They indicate the need for a definitive, large, cooperative, prospective study of all patients who have symptoms and many volunteers who had mild symptoms of esophageal reflux to prove or disprove that relationship.

The effect of secretin on colonic mucin secretion rate in the dog.

A method of quantitation of mucin using chondroitin sulfate A as a standard has been modified and applied to timed mucin collections from surgically created isolated colonic fistulas in 8 dogs. 25 experiments were conducted in which the effect of secretin was tested in 5. The mucin assay is precise and showed increased colonic mucin secretin in response to secretin.

High-resolution magnetic resonance imaging. Technical concepts and their implementation.

In magnetic resonance (MR) imaging manipulating spatial resolution, contrast resolution, and imaging time separately results in improvement in some parameters without degradation of others. The authors have found that MR imaging of the head with a repetition time TR = 2.0 seconds produces images with high signal-to-noise levels and excellent sensitivity to demyelinating disease and brain water content.

Combined use of double- and single-contrast barium enema in the evaluation of suspected colonic disease.

Although controversy has surrounded the use of single- and double-contrast barium enemas for many years, a growing opinion exists that these studies are complementary, each possessing advantages in different clinical settings. We have found that when interpretation of double-contrast studies is difficult because suspected abnormalities are subtle or because technical quality of examinations is less than ideal, single-contrast enemas can be helpful. We have been able to obtain high-quality single-contrast studies using low-viscosity, low-density barium suspensions administered immediately following evacuation after initial air contrast evaluation.

Hepatic tumors: magnetic resonance and CT appearance.

The magnetic resonance (MR) features of primary and metastatic hepatic tumors were analyzed and compared with CT findings in 28 patients. MR images were obtained on a 0.35-Tesla superconducting magnet using a variety of spin echo and inversion recovery imaging techniques.

Clinical nuclear magnetic resonance imaging of the body.

NMR promises great advances in diagnosis and has delivered so much already that it is expected that in the future it will replace many applications of the currently used imaging modalities. Although x-ray computed tomography is continuing to advance in speed of scanning and resolving power, NMR will most likely soon eliminate its use in many studies of the central nervous system and also in many other areas of the body. The promise of combining topical spectroscopy with imaging is also exciting and should provide further information about metabolic processes of various organs.

Nuclear magnetic resonance imaging characteristics of gallstones in vitro.

The nuclear magnetic resonance (NMR) imaging characteristics of gallstones of various composition from 36 patients were studied in vitro using a spin-echo imaging technique. The majority of gallstones (83%) produced no measurable NMR signal despite having a mean water content of 12% and a mean cholesterol content of 61%. Six (17%) of the stones had a weak but measurable signal in the center of the stone, which was thought to represent signal from water in clefts or pores within the stones.

Nuclear magnetic resonance imaging clinical experience in San Francisco.

NMR is a new extremely promising imaging modality that combines the advantages of X-ray computed tomography by giving high resolution tomograms, of ultrasound by allowing imaging in any desired plane without the dangers from ionizing radiation and nuclear medicine by offering information about physiology and metabolic processes. These advantages are not combined with any of the drawbacks of the other modalities, and are due to the ability of NMR to provide information from four imaging parameters: 1) H density; 2) T1--the spin lattice relaxation parameters; 3) T2--the spin-spin relaxation parameter; and 4) information about proton motion. NMR is already a useful clinical tool in the study of brain, cord, mediastinum, pelvis, and is promising in the study of heart, kidneys, adrenals, liver, pancreas, and spleen.

Work in progress: nuclear magnetic resonance imaging of the gallbladder.

A preliminary study of the relation between food intake and intensity of gallbladder bile on nuclear magnetic resonance (NMR) images was made. Twelve subjects (seven volunteers, five patients) were imaged following a minimum of 14 hours of fasting. Six of seven volunteers were reimaged one hour after stimulation by either a fatty meal or an alcoholic beverage.

Hepatic portal venous gas: a benign finding in a patient with ulcerative colitis.

Hepatic portal vein gas (HPVG) usually occurs in conjunction with an abdominal catastrophe such as bowel infarction or necrotizing enterocolitis. We describe this finding after air contrast barium enema in a patient with stable chronic ulcerative colitis who had no symptoms, morbidity, or sequelae, and discuss the diagnostic and therapeutic implications of HPVG.

Nuclear magnetic resonance imaging of mammary adenocarcinomas in the rat.

A study of 24 rats implanted in the hind leg with mammary adenocarcinomas and five sham-implanted rats, followed from the second to the eight week postimplantation, showed nuclear magnetic resonance imaging capable of detecting all the tumors without yielding any false-positives in the control rats. The T1 relaxation time of tumors overlapped that of muscle, and the T2 times overlapped fat, but the combination was unique when comparing tumors to muscle and fat. Necrotic regions of the tumor and the bladder contents tended to have very long T1 and T2 relaxation times.