Ionic versus nonionic contrast media: a prospective study of the effect of rapid bolus injection on nausea and anaphylactoid reactions.

PURPOSE: The purpose of our study was to evaluate the effect of bolus infusion of contrast medium (ionic versus nonionic) on the incidence of nausea and anaphylactoid reactions. METHOD: We prospectively studied 1,827 patients who had bolus enhanced body CT scans and divided them into four groups: 725 patients received higher osmolality contrast medium (HOCM) at the slower bolus rate of 1-2.5 ml/s (SLOW-HOCM group); 650 patients were in the FAST-HOCM group and received the same ionic contrast medium at 4-5 ml/s; 250 patients received lower osmolality contrast medium (LOCM) at 1-2.5 ml/s, forming the SLOW-LOCM group; and 202 patients in the FAST-LOCM group got the same nonionic agent at 4-5 ml/s. RESULTS: We found no significant difference in the rate of nausea among the first three groups: SLOW-HOCM (3.9%), FAST-HOCM (4.9%), and SLOW-LOCM (3.2%). A statistically significant lower incidence of nausea (0.5%) was found in the FAST-LOCM group. Anaphylactoid reactions were significantly more common in both groups who received HOCM (8.3 and 9.1%) compared with the groups who received LOCM (2.0 and 2.5%). CONCLUSION: The bolus injection of warmed ionic contrast medium at a rate of 1-2.5 ml/s causes no significant increase in nausea compared with similar infusion rates of nonionic agents. For CT protocols that require infusion rates of 4-5 ml/s, the use of a nonionic agent is associated with a significantly reduced prevalence of nausea. The prevalence of anaphylactoid reactions is not affected by the rate of injection.

Evaluation of laminin peptide fragments labeled with indium-111 for the potential imaging of malignant tumors.

The laminin peptide fragments GYIGSR-NH2 and CDPGYIGSR-NH2 are known to bind to a 67-kDa laminin receptor. This receptors is understood to be expressed at higher than normal levels in malignant tumor cells, particularly those of breast and colon carcinomas. Peptides DTPA-GYIGSR-NH2 (1), DTPA-(GYIGSR-NH2)2 (2), DTPA-CDPGYIGSR-NH2 (3), DTPA-(CDPGYIGSR-NH2)2 (4), and negative control DTPA-GAGAGA-NH2 (5) were prepared by solid-phase peptide synthesis. All five DTPA-conjugated peptides were subsequently radiolabeled with 111In and their tissue distribution evaluated in mice bearing C3H tumors. 111In-3 and 111In-4 showed the highest specific tumor localization. These preliminary data support further study of radiolabeled petide fragments for the potential detection of malignant tumors of the breast and other organs.

Radiopharmaceuticals as orphan drugs.

Rare diseases and conditions are defined as diseases or conditions that affect less than 200,000 individuals in the United States. Because of the limited population suffering from any given rare disorder, there is little economic motivation for the development of drug products for its diagnosis or treatment. Also, frequently these rare diseases are misdiagnosed or undiagnosed due to a lack of familiarity with their symptoms and course. Thus, these rare disorders are commonly referred to as orphan diseases or conditions. To address this problem, legislation has been enacted that provides for incentives for the development of drug products for rare diseases or conditions (i.e., orphan drug products). Nuclear medicine scientists can take advantage of these incentives in the development of orphan radiopharmaceuticals for the treatment or diagnosis of rare diseases or conditions. Nuclear medicine physicians should know where information on orphan diseases and orphan radiopharmaceuticals can be obtained to maximize the care of their patients.

Dosage of gadoteridol and adverse reactions relative to gadopentetate.

Compliance with an institution's dosage guidelines for gadoteridol was determined, and adverse reactions to gadoteridol and gadopentetate were compared. Departmental policy in March 1993 set the standard dose of gadoteridol at 0.1 mmol/kg. A dose of 0.05 mmol/kg was set for patients with suspected acoustic neurinomas or pituitary microadenomas. Guidelines allowing a high dose of 0.2 or 0.3 mmol/kg were also established for specific indications involving suspected metastatic disease or inadequate contrast enhancement at the standard dose. Data on gadoteridol use were collected concurrently from May 1993 to January 1994 and included the dose, the indication for the dose, and any adverse reactions. Safety data for patients who had received gadopentetate between June 1988 and March 1990 were also collected and reviewed. The subjects in this retrospective analysis represented the same broad population as those involved in the concurrent evaluation of gadoteridol use. The frequency and types of adverse events in the two groups were compared. During the gadoteridol-review period, 8377 patients underwent magnetic resonance imaging studies; 3558 (42.5%) of them received gadoteridol. Of the 3558 doses given, 3375 (94.9%) were 0.1 mmol/kg (the standard dose). Compliance with the guidelines for nonstandard doses was 90% for the 0.3-mmol/kg dose, 74% for the 0.2-mmol/kg dose, and 39% for the 0.05-mmol/kg dose. There were 101 adverse reactions to gadoteridol in 75 (2.1%) of the 3558 recipients. The reactions were mild to moderate and self-limiting. Records for 4892 gadopentetate recipients were analyzed. There were adverse reactions in 62 patients (1.3%). Again, most reactions were mild to moderate. The use of gadoteridol at a medical center generally complied with institutional guidelines. Gadoteridol was well tolerated whether given in standard or high doses. The frequencies and types of adverse reactions to gadoteridol and gadopentetate were similar.

Pharmacist-managed monitoring of adverse reactions to contrast media.

A pharmacist-managed program for reporting, treating, and monitoring adverse drug reactions (ADRs) to contrast media is described. The radiology pharmacist at a 1000-bed multihospital medical center worked with the radiology department to revise departmental policies and procedures for reporting ADRs to contrast media. Under the revision, an ADR report must be completed and forwarded to the pharmacy department and radiology pharmacist for review. In the radiology department itself, ADRs must be documented in the computerized radiology information system in two fields, the patient's radiology file and the radiology study report. The radiology pharmacist developed guidelines for preventing and treating ADRs to contrast media. Boxes containing drugs specifically indicated for the treatment of these ADRs were distributed throughout the radiology department. The radiology pharmacist prepares a quality improvement report each quarter. ADRs documented in the patient's radiology file and in the radiology study report are compared with the total number of ADRs reported. The incidence of ADRs is determined and compared with that for previous quarters and with published data. The treatment of each reaction is evaluated for compliance with the guidelines, the need for follow-up, and any unusual problems. Between July 1991 and December 1992, ADR documentation in the radiology file and in the radiology study report increased substantially in several divisions of the radiology department. The rates of ADRs to contrast media remained fairly constant and paralleled published rates. Compliance with the treatment guidelines was excellent. Pharmacist involvement led to improved reporting of adverse reactions to contrast media in a radiology department and to greater awareness of measures for treating and preventing them.

Acute reactions to intravascular contrast media: types, risk factors, recognition, and specific treatment.

Acute, potentially life-threatening systemic reactions to contrast media are less frequent with lower osmolality, nonionic contrast agents, but they are not totally eliminated. Severe reactions remain a reality in all radiology departments. Typical reactions to contrast media include nausea and/or vomiting, scattered to extensive urticaria, bronchospastic reaction, hypotension (isolated) with compensating tachycardia, anaphylactoid reaction, vagal reaction, cardiovascular collapse, convulsion, and seizure. For each type of reaction, rapid recognition and initiation of specific corrective therapy enhance response and minimize side effects of drugs. Specific drugs for treating each reaction type are reviewed, including recommended dose, contraindications, and alternative choices. An approach to the high-risk patient and prevention of acute systemic reactions is discussed and pretreatment protocols are outlined.

Diagnostic interventions in nuclear medicine.

Diagnostic interventions in nuclear medicine may be defined as the coadministration of a nonradioactive drug or application of a physical stimulus or physiologic maneuver to enhance the diagnostic utility of a nuclear medicine test. The rationale for each interventional maneuver follows from the physiology or metabolism of the particular organ or organ system under evaluation. Diagnostic inference is drawn from the pattern of change in the biodistribution of the tracer in response to the intervention-induced change in metabolism or function. In current practice, the most commonly performed interventional maneuvers are aimed at studies of the heart, genitourinary system, hepatobiliary system, and gastrointestinal tract. The single most commonly performed interventional study in the United States is the stress Thallium-201 myocardial perfusion scan aimed at the diagnosis of coronary artery disease. The stress portion of the study is accomplished with dynamic leg exercise on a treadmill and is aimed at increasing myocardial oxygen demands. Areas of myocardium distal to hemodynamically significant lesions in the coronary arteries become ischemic at peak stress due to the inability of the stenotic vessel to respond to the oxygen demand/blood flow needs of the myocardium. Ischemic areas are readily recognized as photopenic defects on scans obtained immediately after exercise, with "normalization" upon delayed imaging. Diuresis renography is aimed at the differential diagnosis of hydroureteronephrosis. By challenging the urinary tract collecting structures with an augmented urine flow, dilated, unobstructed systems can be differentiated from systems with significant mechanical obstruction. Obstructed systems have a low ability to respond even after effective diuresis, resulting in a characteristic prolonged retention of the radiotracer. Hepatobiliary interventions are most commonly employed in the clinical setting of suspected acute cholecystitis. Administering a cholecystogogue before a hepatobiliary tracer promotes visualization of the gallbladder by causing it to go through a contraction/filling cycle in which the filling phase occurs during maximum exposure to the radionuclide. This maneuver can convert a false positive study that suggests the presence of acute cholecystitis to a true negative study. Other gastrointestinal interventions are aimed at enhancing the detection of gastroesophageal reflux and gastrointestinal bleeding. Many new interventions have been developed that are currently aimed at research problems rather than clinical problems.(ABSTRACT TRUNCATED AT 400 WORDS)

African American adolescents: adaptational processes and socioeconomic diversity in behavioural outcomes.

The study was concerned with determining the relationship of economic diversity to stress reactivity. Parental ratings of competence and behavioural problems were obtained for very young adolescents following a long-term and highly acute stress: the Atlanta youth murders. Intellectual and identity-formation data obtained both before and after the crisis were analyzed with the parental ratings of youth competence and behavioural problems. Consistent socioeconomic status (SES) links between the manifestation of behavioural problems and the display of competencies were obtained; lower income (LI) youths manifested more problems and fewer competencies. The findings were more pronounced for LI males. Personal identity was a significant predictor of school competence. School self-esteem was a predictor of academic performance. The manifestation of behavioural problems was significantly predicted by cognitive performance variables. The findings are discussed in terms of variations in adaptational strategies mediated by socioeconomic status and psychological factors.

Portal hypertension workup by DSA.

To provide information for preoperative planning, combined, selective intravenous (IV) and intraarterial (IA) digital subtraction angiography (DSA) studies were performed on 42 portal hypertension patients scheduled for portal systemic shunt procedures. Selective IV-DSA was performed to demonstrate the hepatic venous system, left renal vein, and inferior vena cava. Portal venous anatomy, direction of flow, and portal systemic collaterals were evaluated by selective IA-DSA. In addition, selective IA-DSA was performed postoperatively on 8 patients to assess shunt patency. Technically adequate DSA studies, suitable for surgical planning or postoperative assessment, were obtained in all of the 50 patients examined. Patient or internal organ motion was not a limiting factor in any study. Such use of DSA represents an efficacious, safe, and cost-effective alternative to conventional film-screen angiography for the evaluation of patients with portal hypertension.

Failure of technetium-99m sulfur colloid uptake by the femoral head. Aseptic necrosis or normal variation?

The hips of 79 asymptomatic patients having Tc-99m sulfur colloid liver/spleen scans were imaged. Patients were not studied if they had a disease associated with nonvisualization of the femoral heads. The first group consisted of 47 consecutive patients who were imaged in a neutral position. Eighteen right and 18 (38.3%) left hips showed no activity. The second group consisted of 32 consecutive patients who were imaged in an internally rotated position. Seven (21.9%) right and nine (28.1%) left hips showed no activity. This study concludes that failure of uptake of Tc-99m sulfur colloid by the femoral head is seen in a sufficiently large group of patients to limit its use in diagnosing aseptic necrosis.

Evaluation of intravascular low-osmolality contrast agents.

The chemistry of low-osmolality contrast agents is reviewed, the effects of these agents on vascular and organ physiology are compared with the effects of conventional ionic contrast media, and guidelines for intravascular use of the low-osmolality agents in selected high-risk patients are presented. Three low-osmolality contrast agents, the nonionic media iohexol (Omnipaque, Winthrop-Breon) and iopamidol (Isovue, Squibb) and the dimeric medium ioxaglate meglumine-sodium (Hexabrix, Mallinckrodt) have recently been introduced into the contrast-media market. Compared with conventional ionic contrast media, these new agents demonstrate approximately one third of the osmolality per given iodine concentration (degree of roentgenographic opacification). Therefore, the risks of hyperosmolarity-induced reactions to contrast media are lower with the new agents. The low-osmolality agents may be associated with a reduced incidence of contrast-media-induced hypersensitivity reactions. Because of their lower osmolality, these agents produce less vessel dilation, vascular endothelial damage, and associated pain and discomfort than equi-iodine concentrations of the conventional ionic media. They also demonstrate a reduction in the incidence and severity of contrast-media-induced renal vasoconstriction and proteinuria, hemodynamic alterations, negative chronotropic effects, depression of myocardial contractility, and neurotoxicity in the presence of an altered blood-brain barrier. These low-osmolality agents produce fewer undesirable physiological effects than conventional contrast agents, but the cost of the new products can be more than 10 times as great. Therefore, the new products should be used selectively in patients known to be at increased risk for reactions to intravascular contrast media. A scoring system was developed to permit rapid recognition of documented single or multiple risk factors and subsequent determination of whether to administer a low-osmolality agent.

Developing marketing pamphlets for diagnostic radiology services.

The marketing of professional services requires an approach that differs from that utilized in the conventional marketing of products and services. This article describes the considerations that were involved in the development and implementation of marketing pamphlets for diagnostic radiology services.

Product selection criteria for intravascular ionic contrast media.

The chemistry, clinical use, pharmacokinetics, adverse reactions, dosages, and formulary recommendations for intravascular ionic contrast media routinely used in radiologic procedures are reviewed. The meglumine, sodium, or combined meglumine-sodium salts of triiodinated benzoic acid derivatives, diatrizoic and iothalamic acid, are commonly used as intravascular ionic contrast media for radiographic visualization of blood vessels and the urinary tract. Meglumine salts of iodoxamate and iodipamide are used for intravenous cholangiography. The iodine in the contrast medium is responsible for the absorption of x-rays and the resulting opacification of the organ system or other area under investigation. Adverse reactions to intravascular ionic contrast media broadly include hypersensitivity and chemotoxic reactions. The incidence of major life-threatening hypersensitivity reactions, such as severe hypotension, cardiac arrhythmias or arrest, pulmonary or laryngeal edema, and convulsions, is estimated at 0.01-0.1% of the population receiving these agents. Dose- and concentration-dependent chemotoxic reactions result from the direct effects of the contrast medium on the blood vessels or organs being perfused. The meglumine salts of diatrizoic acid and iothalamic acid are less toxic in the cerebral circulation than sodium salts; hence, diatrizoate meglumine or iothalamate meglumine are recommended for cerebral angiography. In coronary angiographic examinations, combined meglumine and sodium (6.6 parts meglumine to 1 part sodium) formulations of diatrizoate are recommended because they consist predominantly of the meglumine salt with minimal but adequate amounts of sodium to prevent ventricular fibrillation. Predominantly meglumine salts of diatrizoic and iothalamic acid are also used for peripheral angiography, computerized tomography, and digital subtraction angiography. The dosages of ionic contrast media vary considerably depending on the nature of the radiological examination, the respective technique employed, and the age and condition of the patient. The cost differences between diatrizoate and iothalamate media are typically minimal. Formulary recommendations regarding the appropriate chemical nature of these media are based on the reported adverse reactions with these agents.