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Biomedical subjects

V M Runge

Publications and source records attributed to V M Runge.

At least 55 records · Page 3Linked to original sources
PubMed1995

Comparison of gadolinium Cy2DOTA, a new hepatobiliary agent, and gadolinium HP-DO3A, an extracellular agent, in healthy liver and metastatic disease.

RATIONALE AND OBJECTIVES: A new gadolinium (Gd) chelate with preferential hepatobiliary uptake, Gd Cy2DOTA, was compared in two animal species with Gd HP-DO3A (gadoteridol), a clinically approved contrast agent with extracellular distribution. Liver enhancement was evaluated for these two contrast agents using magnetic resonance imaging, whereas an experimental model of metastatic disease was used to evaluate the agents' efficacy for liver-lesion delineation. METHODS: The two agents were compared in four healthy Rhesus monkeys (eight studies) and five New Zealand White rabbits with implanted VX-2 liver tumors (ten studies). The contrast dose was 0.1 mmol/kg, with the agents given in random order and at least 72 hours between contrast injections. Breathhold T1-weighted spin echo scans were obtained at 1.5 tesla (T) before and after contrast was administered. Postcontrast scans were obtained 1 to 90 minutes after injection in the monkeys and 1 to 240 minutes after injection in the rabbits. RESULTS: Prolonged hepatic enhancement, superior in degree to that with Gd HP-DO3A, was noted in both monkeys and rabbits after injection of Gd Cy2DOTA. Two minutes after contrast, liver SI was 1.94 +/- 0.05 with Gd Cy2DOTA compared with 1.51 +/- 0.05 with Gd HP-DO3A in monkeys. Sixty minutes after contrast, liver SI was 1.60 +/- 0.09 compared with 1.20 +/- 0.02. The difference between agents was significant at all times from 2 to 60 minutes after contrast injection (P < 0.01). Excretion of contrast into the gall bladder was observed in both animal species with Gd Cy2DOTA but not with Gd HP-DO3A. The maximum improvement in lesion conspicuity (rabbit) occurred 45 minutes after injection of Gd Cy2DOTA and 5 minutes after injection of Gd HP-DO3A. Sixty minutes after injection, liver-lesion contrast was 246 +/- 61 with Gd Cy2DOTA and 106 +/- 28 with Gd HP-DO3A, with a significant difference (P < 0.02). CONCLUSIONS: Gd Cy2DOTA provides greater enhancement of the liver parenchyma on immediate and delayed magnetic resonance scans than does Gd HP-DO3A. On delayed scans, Gd Cy2DOTA provides superior delineation of metastatic liver lesions.

Adenocarcinoma↗
PubMed1995

Magnetization transfer and high-dose contrast in early brain infection on magnetic resonance.

RATIONALE AND OBJECTIVES: The authors studied the effect of contrast dose, use of magnetization transfer (MT), and temporal delay on the visualization of contrast enhancement with gadoteridol (Gd HP-DO3A) in a canine brain abscess model. METHODS: Alpha streptococcus brain abscesses were studied in five dogs at 1.5 tesla (T) 1 and 5 days after implantation. Scans were performed 1, 11, and 21 minutes after contrast was administered, using an initial dose of 0.1 mmol/kg. A supplemental contrast injection of 0.2 mmol/kg was given (for a cumulative dose of 0.3 mmol/kg), with scans repeated at 31, 41, and 51 minutes. RESULTS: Lesion conspicuity on day 1 was greater at high-contrast doses (0.3 mmol/kg) compared with standard doses (0.1 mmol/kg), regardless of whether imaging was performed without (0.89 +/- 0.02 compared with 0.26 +/- 0.08) or with (0.97 +/- 0.04 compared with 0.28 +/- 0.06) MT. High-dose, MT, and a delay after contrast was injected all produced a statistically significant improvement. On blinded review of films obtained 11 and 14 minutes after injection, enhancement of the lesion could not be identified with certainty in two of five dogs at a dose of 0.1 mmol/kg, regardless of whether MT was used. Enhancement was seen consistently in all lesions at 0.3 mmol/kg. On day 5, results were comparable, with greater absolute enhancement. CONCLUSIONS: In early brain infection, high-contrast doses (0.3 mmol/kg), MT, and a moderate delay after injection all improve visualization of lesion enhancement.

Animals↗
PubMed1995

Detectability of early brain meningitis with magnetic resonance imaging.

RATIONALE AND OBJECTIVES: The ability of high-field (1.5 T) magnetic resonance imaging (MRI) to detect early brain meningitis was evaluated in a canine model. Contrast dose, timing postinjection, and imaging technique (specifically the use of magnetization transfer) were assessed. METHODS: Imaging of five canines was performed at 1.5 T 24 hours after injection of Cowans staphylococcus into the cisterna magna. Two control animals also were imaged using the same protocol, with one animal receiving a cisternal injection of nutrient broth only and the other no injection. Contrast doses of 0.1, 0.3, and 0.8 mmol/kg gadoteridol (Gd HP-DO3A or Pro-Hance) were compared. Scans were performed at 2, 12, and 22 minutes after an initial injection of 0.1 mmol/kg. At each time point, paired T1-weighted scans with and without magnetization transfer (MT) were acquired. Thirty minutes after the initial injection of contrast, a supplemental dose of 0.2 mmol/kg was given (for a cumulative dose of 0.3 mmol/kg). Scans were then repeated at 2, 12, and 22 minutes after this dose was administered. A second supplemental contrast injection of 0.5 mmol/kg (for a cumulative dose of 0.8 mmol/kg) was given at 70 minutes, and immediate postinjection scans with and without MT were acquired. RESULTS: In the animals receiving a cisternal injection of bacteria, the degree of meningeal enhancement was greatest at 0.8 mmol/kg, intermediate at 0.3 mmol/kg, and least at 0.1 mmol/kg. These conclusions were constant whether imaging was performed with or without MT. Scans in control studies did not demonstrate abnormal meningeal enhancement. High-contrast dose, MT, and acquisition of immediate postcontrast scans all resulted in statistically significant improvement. On masked film review, abnormal meningeal enhancement was noted in only 2 of 5 experimental dogs at a dose of 0.1 mmol/kg (regardless of the use of MT) compared with all animals at a dose of 0.3 mmol/kg. In 18 of 37 dogs (paired scans with and without MT), when abnormal enhancement was noted, the use of MT improved the visualization of abnormal meningeal enhancement. CONCLUSIONS: In early brain meningitis, high-contrast dose (0.3 mmol/kg), MT, and scanning immediately after injection improve detection of abnormal meningeal enhancement, thus facilitating the diagnosis of meningitis. Of these factors, contrast dose is the most important.

Animals↗
PubMed1995

Hepatic MR imaging with ferumoxides: a multicenter clinical trial of the safety and efficacy in the detection of focal hepatic lesions.

PURPOSE: To assess the safety and diagnostic efficacy of intravenous ferumoxides, a superparamagnetic iron oxide, for depiction of focal hepatic lesions on magnetic resonance (MR) images. MATERIALS AND METHODS: This open-label study included 208 patients with known or suspected focal hepatic lesions. MR images were obtained before and 45 minutes to 4 hours after intravenous infusion of ferumoxides (10 mumol/kg). The effect of ferumoxides on signal intensity of the liver was assessed with quantitative analysis. Safety was evaluated with patient monitoring and laboratory measurements. RESULTS: Mean lesion-to-liver contrast-to-noise ratio on T2-weighted images was 9.1 on unenhanced images and 12.7 on enhanced images. Signal intensity of normal liver on enhanced images decreased to 37% of that on unenhanced images. In blinded image evaluations, additional lesions were identified on 27% of enhanced images. No serious adverse events occurred. CONCLUSION: Ferumoxides is a safe and efficacious contrast agent for the detection of focal liver lesions on T2-weighted images.

Contrast Media↗
PubMed1995

Gadoteridol-enhanced MR imaging of malignant hepatic tumors: effects of triple versus standard doses on lesion-liver contrast.

OBJECTIVE: The purpose of this study was to compare liver signal-to-noise ratio (SNR), lesion SNR, and lesion-liver contrast-to-noise-ratio (CNR) in patients with malignant liver lesions after the administration of a standard dose (0.1 mmol/kg of body weight) or a triple dose (0.3 mmol/kg) of a gadolinium chelate (gadoteridol). We hypothesized that the higher dose would produce a higher lesion-liver CNR and therefore increase the conspicuity of hepatic lesions. MATERIALS AND METHODS: A total of 85 patients with malignant hepatic masses (61 metastases, 22 hepatocellular carcinomas, and two lymphomas) proved by histologic or follow-up studies underwent MR imaging at 1.5 T. T1-weighted spin-echo imaging and gradient-echo imaging were done before and within 1 min after (gradient echo) as well as 5 (spin echo) and 15 (spin echo) min after the injection of 0.1 or 0.3 mmol of gadoteridol per kg, randomized before the start of the study (39 patients received the standard dose, and 46 received the triple dose). The signal intensities of the liver and lesions and the SD of background noise were measured by use of regions of interest to calculate the SNR of the liver and malignant lesions and the lesion-liver CNR. RESULTS: The lesion-liver CNR was increased significantly at 5 and 15 min after the administration of gadoteridol. No significant differences in the liver SNR, lesion SNR, and lesion-liver CNR (after 1 min: standard dose, -5 +/- 8, and triple dose, -4 +/- 14; after 5 min: standard dose, -1 +/- 5, and triple dose, 2 +/- 8; and after 15 min: standard dose, 1 +/- 5, and triple dose, 6 +/- 20) were found between the doses at all time points. CONCLUSION: Triple-dose gadoteridol does not improve the lesion-liver contrast of malignant hepatic lesions over that provided by the standard dose and is not warranted for liver MR imaging.

Adult↗
PubMed1995

Basic principles of MR contrast.

The use of intravenous contrast media is well established in magnetic resonance (MR) for improved diagnosis. MR differs from other imaging modalities in the complexity of signal and contrast dependence, with the method of measurement having great impact on tissue contrast. Unlike computed tomography, in which contrast depends solely on x-ray density, the signal intensity on MR is determined by differences in spin density, T1 and T2 relaxation times, diffusion, perfusion, and magnetic susceptibility. The only contrast agents in widespread clinical use at this time are paramagnetic metal ion chelates. These compounds influence tissue contrast by enhancing T1 and T2 relaxation. The effectiveness of any one agent is dependent on a number of basic parameters, including concentration, number of coordination sites, magnetic moment, distance between the ion and water protons, and correlation times. An understanding of general contrast mechanisms, principles of contrast agent design, and basic MR imaging techniques is important for proper clinical implementation and medical diagnosis.

Central Nervous System Diseases↗
PubMed1995

The use of MR contrast in neoplastic disease of the brain.

Magnetic resonance imaging (MRI) is the modality of choice in the evaluation of patients with actual or suspected intracranial neoplasms. MRI has many advantages over alternative modalities. It provides increased sensitivity, permits multiplanar image display, is noninvasive, and has no associated ionizing radiation. MR contrast adds significantly to the evaluation of patients with suspected intracranial neoplasms. It further increases sensitivity to lesion detection, it more clearly defines tumor extent, and it facilitates the differentiation of tumor from normal adjacent structures. In virtually every instance, MR contrast enhances lesion conspicuity. In some cases, these neoplasms would be seen only with difficulty or not at all without the benefit of contrast enhancement. Thus, in the appropriate patient population, MR contrast enables more time-efficient and cost-effective diagnoses.

Brain↗
PubMed1995

The use of MR contrast in nonneoplastic disease of the brain.

The clinical utility of intravenous contrast administration in nonneoplastic disease of the brain is well established. Although primarily providing improved diagnostic specificity, contrast use can also improve lesion detection. Applications are discussed in infection, vascular disorders, diseases of white matter, and trauma. On the basis of prospective studies, contrast use is advocated in all patient examinations in which there is a high clinical suspicion for intracranial disease. The role of high-dose contrast administration, with agents such as gadoteridol (Gd HP-DO3A), is just now being explored in nonneoplastic disease. Basic research suggests efficacy for high dose in disease states with partial or early blood-brain barrier disruption. Gadolinium chelates play as important a role in the evaluation of nonneoplastic disease of the brain as do iodinated agents in computed tomography. Contrast administration facilitates time-efficient and cost-effective diagnosis.

Brain↗
PubMed1995

The use of MR contrast agents in the evaluation of disease of the spine.

In the last decade, magnetic resonance (MR) of the spine has become the imaging modality of choice, superseding both computed tomography (CT) and myelography, for the evaluation of a broad spectrum of disease entities. The capability for multiplanar imaging, the use of nonionizing radiation, and the ability to obtain a myelographic-like image (without intrathecal contrast injection) all provide distinct advantages. This article reviews the current applications of intravenous contrast media in MR for evaluation of the spine and its contents. In many instances, contrast enhancement plays a valuable role in developmental disease, trauma (e.g., disk herniation, both before and after surgery), infection, vascular disease, neoplasia, degenerative disease (e.g., neurogenic claudication), and demyelinative processes (e.g., multiple sclerosis).

Contrast Media↗
PubMed1995

Update: safety, new applications, new MR agents.

In the last decade, i.v. contrast media use in magnetic resonance imaging (MRI) of the central nervous system has become well established. Three agents are currently available in the United States: gadopentetate dimeglumine (Magnevist), gadodiamide (Omniscan), and gadoteridol (ProHance). At a dose of 0.1 mmol/kg, for which all three agents are approved, the contrast effect is equivalent. The agents differ on the basis of stability in vivo, osmolality, and charge. A single agent (ProHance) is approved for high-dose administration (0.3 mmol/kg). The basis of this approval is due in part to the high stability of the agent and thus lower potential for toxicity from long-term heavy metal deposition. Clinical experience, combined with new developments in MR technology, continue to expand applications for these agents. Improved detection of metastatic disease to the brain has been demonstrated in multiple clinical trials with high-dose contrast administration. High dose may also play an important role in brain infection and infarction, providing improved recognition of blood-brain barrier disruption and thus disease activity. First-pass studies make possible the evaluation of regional cerebral blood volume with high intrinsic spatial resolution. The availability of new instrumentation, together with the use of high contrast dose, have improved the quality and clinical utility of these studies. Research is ongoing in the development of new agents, both with greater tissue selectivity and improved safety profile. Chelates of dysprosium, in addition to gadolinium, are receiving attention for potential clinical application in first-pass imaging.

Animals↗
PubMed1994

Magnetic resonance imaging of an experimental model of intracranial metastatic disease. A study of lesion detectability.

RATIONALE AND OBJECTIVES: The detectability of brain metastases was evaluated in a rabbit model, with attention to magnetic resonance contrast dose and timing of image acquisition after injection of contrast medium. METHODS: Five New Zealand white rabbits were studied at 1.5 T 6 to 7 days and 11 to 12 days after surgical implantation of an adenocarcinoma tumor nidus. T1- and T2-weighted spin-echo images (0.9 x 0.9 x 2 mm3 voxel size) were obtained before administration of contrast medium. T1-weighted images were repeated 5, 15, and 30 minutes after intravenous injection of 0.1 mmol/kg gadoteridol. At 40 minutes, a supplemental dose of 0.2 mmol/kg (0.3 mmol/kg cumulative dose) was administered, with T1-weighted images repeated at 5, 15, and 30 minutes after the second injection. RESULTS: Six to 7 days after tumor implantation, lesion enhancement (percent change, with normalization to baseline and equilibrium values) was 42 +/- 9% at 5 minutes, 48 +/- 9% at 15 minutes, and 42 +/- 10% at 30 minutes after administration of 0.1 mmol/kg gadoteridol. After administration of 0.3 mmol/kg gadoteridol, lesion enhancement was 111 +/- 13% at 5 minutes, 116 +/- 8% at 15 minutes, and 100% at 30 minutes. On film review, 2 of 5 lesions were not detectable at 6 to 7 days after tumor implantation with 0.1 mmol/kg gadoteridol. Administration of 0.3 mmol/kg gadoteridol provided for lesion identification in each instance. Eleven to 12 days after tumor implantation, one lesion was not detectable with 0.1 mmol/kg gadoteridol. Administration of 0.3 mmol/kg gadoteridol again provided for lesion identification in all cases. Mean lesion enhancement increased from 39 +/- 15% to 104 +/- 10%. CONCLUSIONS: The administration of 0.3 mmol/kg gadoteridol (high dose) compared with 0.1 mmol/kg gadoteridol (conventional dose) improves metastatic lesion detectability in the brain. The lesions identified only at high dose were confirmed by histopathology. Smaller lesions were not detected at a dose of 0.1 mmol/kg.

Adenocarcinoma↗
PubMed1994

Initial clinical experience with dextran-coated superparamagnetic iron oxide for detection of lymph node metastases in patients with head and neck cancer.

PURPOSE: To investigate the efficacy of magnetic resonance (MR) imaging with dextran-coated superparamagnetic iron oxide in the differentiation of metastatic and benign nodes in patients with head and neck cancer. MATERIALS AND METHODS: MR imaging was performed before and after intravenous administration of iron oxide in 12 patients. Ninety-one pathologically proved nodes were visually analyzed, and 66 lymph nodes were quantitatively analyzed by measuring signal intensity in visually selected regions of interest. RESULTS: Forty of 42 histologically proved metastatic nodes and 41 of 49 benign nodes were detected, yielding 95% sensitivity and 84% specificity. The signal intensity ratio of benign nodes was substantially lower than that of metastatic nodes, indicating better differentiation of metastatic and benign nodes. Furthermore, 13 of 14 normal-sized nodes were detected. CONCLUSION: MR imaging with iron oxide can enable specific differentiation of metastatic and benign nodes in patients with head and neck cancer. This agent may potentially enhance the detection of metastatic lymph nodes and deserves further investigation.

Adult↗
PubMed1994

Hepatic metastases and cavernous hemangiomas: distinction with standard- and triple-dose gadoteridol-enhanced MR imaging.

PURPOSE: To determine if hepatic metastases can be distinguished from cavernous hemangiomas by pattern analysis of magnetic resonance (MR) images obtained prior to and following administration of gadoteridol at standard (0.1 mmol/kg) and triple (0.3 mmol/kg) doses. MATERIALS AND METHODS: Ninety-five patients with proved hepatic metastases (n = 71) or cavernous hemangiomas (n = 24) underwent MR imaging at 16 different institutions. T2-weighted spin-echo and T1-weighted images were obtained before and after gadoteridol administration. Two independent blinded reviewers rated individual features of benignancy versus malignancy on a five-point confidence scale. RESULTS: The most useful diagnostic features, with 100% specificity, were nodular enhancement for hemangiomas and rim enhancement for metastases. Confident (definitely benign or definitely malignant) diagnoses were rendered in 80 of 95 cases (84%), with an accuracy of a confident diagnosis of 96%. CONCLUSION: The pattern of enhancement on T1-weighted images is highly accurate for distinction between hemangiomas and metastases in images obtained with both doses.

Contrast Media↗
PubMed1994

Visualization of blood-brain barrier disruption on MR images of cats with acute cerebral infarction: value of administering a high dose of contrast material.

OBJECTIVE: The detection of blood-brain barrier disruption in patients with cerebral infarction by means of contrast-enhanced MR images improves the specificity of diagnosis, enables lesion dating, and on occasion improves lesion detection. Accordingly, we performed a study to determine the extent of visualization of disruption of the blood-brain barrier on contrast-enhanced MR images, with specific attention to contrast dose, in a cat model of acute cerebral infarction. We used doses of 0.1 and 0.3 mmol/kg of a gadolinium chelate, gadoteridol, which is characterized by extracellular distribution and renal excretion, and was approved by the Food and Drug Administration for clinical use at these doses. MATERIALS AND METHODS: Blood flow in the middle cerebral artery was occluded unilaterally in seven cats for 1 hr, followed by 4 hr of reperfusion. T2- and T1-weighted MR images were obtained before the injection of contrast material. After injection, the time course of enhancement was observed for 1 hr by repeated sequential acquisition of T1-weighted images. Five cats received an initial injection of 0.1 mmol/kg of contrast material, supplemented 33 min later by 0.2 mmol/kg (cumulative dose, 0.3 mmol/kg). Two cats received a single injection of contrast material, either 0.1 or 0.3 mmol/kg. The images were reviewed in a prospective fashion by a single observer, who was blinded to the dose of contrast material and the timing of image acquisition, in order to detect abnormal contrast enhancement. Changes in single intensity were quantified by region-of-interest measurements. RESULTS: Enhancement at 4 and 13 min, respectively, after injection of contrast material was 25 +/- 10% and 38 +/- 7% with 0.1 mmol/kg, vs 80 +/- 12% and 100 +/- 15% with 0.3 mmol/kg (n = 5). The difference between doses was statistically significant (p < .002) for all time points. Abnormal contrast enhancement was visible in three of six cats that received 0.1 mmol/kg and in all cats that received 0.3 mmol/kg. By 13 min after injection, enhancement had peaked with a dose of 0.1 mmol/kg and was within 20% of maximum with a dose of 0.3 mmol/kg. CONCLUSION: Detection of disruption of the blood-brain barrier in acute cerebral infarction in cats is improved when high doses (0.3 mmol/kg) of contrast material are used. Disruption may not be visualized when 0.1 mmol/kg, the currently accepted standard dose, is used.

Animals↗
PubMed1994

Delineation of gliomas with various doses of MR contrast material.

PURPOSE: To examine the effects of different gadolinium doses on the delineation of gliomas, particularly the demonstration of abnormal enhancement on T1-weighted images extending beyond the zone of apparent signal abnormality on corresponding T2-weighted images. METHODS: During phase II clinical trials of gadoteridol, 23 patients with pathologically proved gliomas were studied by MR with various doses of gadoteridol, ranging from 0.05 to 0.3 mmol/kg. RESULTS: All of the gliomas were readily detected by T2-weighted images. Twelve of 23 patients demonstrated enhancement on T1-weighted images extending beyond the zone of apparent signal abnormality demonstrated on T2-weighted images. These findings were seen in none of the six patients (0%) studied at 0.05 mmol/kg, one of five patients (20%) studied at 0.1 mmol/kg, four of five patients (80%) studied at 0.2 mmol/kg, and seven of seven patients (100%) studied at 0.3 mmol/kg. CONCLUSIONS: The detection of symptomatic gliomas does not require a contrast agent because they are generally large and readily demonstrated on T2-weighted images. However, the area of postcontrast enhancement of gliomas seems to be greater with higher doses of contrast agent. The cause of the abnormal enhancement extending beyond the zone of apparent signal abnormality on T2-weighted images seen in this limited study is unknown and probably represents tumor infiltration. The frequency of detection of such findings appears to be proportional to the dose of contrast material used.

Brain↗
PubMed1994

Phase III multicenter trial of high-dose gadoteridol in MR evaluation of brain metastases.

PURPOSE: To assess the efficacy and safety profile of high-dose (0.3 mmol/kg cumulative dose) gadoteridol in patients with suspected central nervous system metastatic disease. METHODS: We studied 67 patients using an incremental-dose technique. Patient monitoring included a medical history, physical examination, vital signs, and extensive laboratory tests within 24 hours before and after the MR examination. Precontrast T1- and T2-weighted spin-echo studies were performed, followed by intravenous injection of 0.1 mmol/kg of gadoteridol. T1-weighted images were acquired immediately after and at 10 and 20 minutes after injection. At 30 minutes an additional 0.2 mmol/kg of gadoteridol was administered (0.3-mmol/kg cumulative dose), and T1-weighted images were acquired. Cases demonstrating abnormal MR findings were assessed for efficacy by unblinded and blinded reviewers and were analyzed quantitatively. RESULTS: Three adverse effects in two patients were considered to be related to gadoteridol administration. No adverse effects were serious; all self-resolved. Forty-nine cases showed abnormal MR findings and were included in the efficacy analysis. A significantly greater number of lesions was seen on the high-dose as opposed to the standard-dose images. Blinded and unblinded readers identified 5 and 8 patients, respectively, with solitary lesions on standard-dose examination and multiple lesions on high-dose examination. Two patients who had normal standard-dose findings had lesions identified on high-dose studies. Quantitative analysis of 133 lesions in 45 patients demonstrated significant increases in lesion signal intensity on high-dose studies when compared with standard-dose studies. CONCLUSION: Gadoteridol can be safely administered up to a cumulative dose of 0.3 mmol/kg. High-dose contrast studies provide improved lesion detectability and additional diagnostic information over studies performed in the same patients with a 0.1-mmol/kg dose and aid in patient diagnosis and treatment. High-dose gadoteridol study may facilitate the care of patients with suspected central nervous system metastasis.

Adolescent↗
PubMed1994

Magnetic resonance contrast agents in neuroimaging. New agents and applications.

Of the four gadolinium chelates in clinical use worldwide, only three are available in the United States: gadoteridol, gadodiamide, and gadopentetate dimeglumine. Although gadopentetate dimeglumine is still administered in many clinical practices, a consequence of being the first agent developed (1988) and until recently the only agent available, gadoteridol demonstrates a higher index of safety--at least on theoretical grounds. With linear chelates such as gadopentetate dimeglumine and gadodiamide, greater release of free gadolinium ion occurs in vivo owing to lower thermodynamic and kinetic stability. The concern with respect to demetallation and resultant increased chronic deposition of gadolinium ion in marrow and liver is greater with gadodiamide. Drug safety appears not to be an issue at high dose for gadoteridol, the only agent approved in this regards. The safety of the other chelates at high dose has yet to be established. The nonionic character of the two newer agents (gadoteridol and gadodiamide) is not of great importance in current clinical practice, in which most examinations are still performed with a dose of 0.1 mmol/kg given as a slow infusion. The non-ionic nature of the newer MR contrast agents may become clinically important in the future, with more common application of bolus injection and high dose. High contrast dose (0.3 mmol/kg) is advocated in routine MR clinical practice for the evaluation of intracranial metastatic disease. Only with prior evidence for multiple metastases and in patients for whom the detection of additional lesions would not influence therapy can the use of standard dose (0.1 mmol/kg) be justified.(ABSTRACT TRUNCATED AT 250 WORDS)

Brain↗