Optimization of contrast dosage for gadobenate dimeglumine-enhanced high-resolution whole-body 3D magnetic resonance angiography

Effects of Height and Blood Volume on Venous Enhancement After Gadolinium-Based Contrast Administration in MR Venography: A Paradigm Challenge and Implications for Clinical Imaging

OBJECTIVE

The purpose of this study was to analyze quantitative and qualitative effects of estimated blood volume on venous enhancement in patients undergoing cerebral MR venography (MRV) with standard weight-based dosing of a gadolinium-based contrast agent.

MATERIALS AND METHODS

Fifty-two patients with normal 1.5-T cerebral MRV findings and contemporaneous height and weight measurements were included. Estimated blood volume was calculated with the Nadler formula for blood volume. Standard weight-based cerebral MRV was performed after administration of gadobenate dimeglumine (0.1 mmol/kg up to 20 mL). Venous enhancement within the superior sagittal sinus, right jugular bulb, and left jugular bulb was measured. Patients were dichotomized on the basis of administration of less than versus a maximum weight-based gadolinium-based contrast dose of 20 mL. Venographic quality was assigned by two neuroradiologists. Correlational and multiple linear regression analyses were performed.

RESULTS

Among patients receiving less than the maximum 20 mL of gadolinium, no significant correlations were observed between weight and vascular enhancement (p > 0.05). Significant correlations between height and enhancement were observed in the superior sagittal sinus and left jugular bulb. This finding suggests that differences in estimated blood volume driven by height remain unaccounted for (p < 0.05). With the 20-mL maximal dose, a significant inverse relation was noted between estimated blood volume and contrast enhancement of all vascular segments (p < 0.05). Within all vascular segments, significant correlations were observed between enhancement and user-defined quality scores (p < 0.05). This finding suggests that optimized dosing may affect reader confidence.

CONCLUSION

Standard weight-based dosing for cerebral MRV insufficiently accounts for differences in circulating blood volume. An expanded biometric dosing paradigm leveraging readily attainable subject data may mitigate unintended variations in enhancement affecting venography and other clinical imaging modalities.

Cardiovascular whole-body MRI

Cardiovascular diseases still rank number one in mortality statistics in the industrialized world. In these countries the five most common causes of death are associated to atherosclerotic changes of the arterial vasculature. Due to its often long lasting treatment and the possible loss of ability to work atherosclerotic disease constitutes an economic factor which should not be disregarded. Thus screening for atherosclerotic disease seems to be reasonable because as known the potential to influence atherosclerotic changes is higher in an early stage of the disease. Not in every case it is possible to cure the disease but sometimes progression can be controlled and decelerated. Imaging of the arterial vasculature was limited to invasive procedures associated with ionizing radiation for a long time. Non-invasive exams like the "ankle-brachial-index" (ABI) can indicate the presence of PAOD, an exact localization of the pathologic changes is only possible with imaging methods. For cardiac imaging likewise the only non-invasive exams have been ECG and auscultation. Certainly echocardiography is an excellent technique to access cardiac function but it depends very much on both, the examining physician and the patient. MRI constitutes a non-invasive imaging modality without ionizing radiation offering excellent reproducible image quality.

[Whole body MRI--diagnostic strategy of the future?]

Whole body magnetic resonance imaging (MRI) opens new opportunities in diagnostic radiology as systemic disease entities can be examined with high sensitivity. This can lead to a change of paradigm, so that not only organ-related but rather disease-specific MRI examination protocols can be applied which focus on the underlying pathophysiology of the disease. Whole body MRI has already been successfully used for several oncological and non-oncological indications. In addition, whole body MRI has broadened the discussion regarding its use for secondary prevention. Compared to computed tomography, MRI does not use radiation. Although whole body MRI is still in an early stage, the enormous medical and economical potential can be envisioned.

First-Pass Whole-Body Magnetic Resonance Angiography (MRA) Using the Blood-Pool Contrast Medium Gadofosveset Trisodium

OBJECTIVES

To evaluate gadofosveset trisodium for first-pass magnetic resonance angiography (MRA) in the setting of whole-body MRA (WB-MRA).

MATERIALS AND METHODS

Forty patients were examined using either 10 mL gadofosveset trisodium (n = 20) or 30 mL gadopentetate dimeglumine (n = 20), followed by arterial-phase imaging of 4 consecutive anatomic regions. Signal intensity was measured in 2 vessels per region. Relative contrast values (RC) were calculated. Arterial contrast, venous overlay, and image quality were rated by 2 radiologists. The Mann-Whitney U test was used to test for significance.

RESULTS

Compared with gadopentetate dimeglumine, gadofosveset trisodium enhanced imaging revealed higher RC values in 2 vessel regions, with the differences being significant in 3 of 4 vessel segments. Gadofosveset trisodium revealed lower RC values in 2 regions with significant differences in 2 segments. Qualitative evaluation revealed higher ratings for gadofosveset trisodium regarding all 3 criteria with significant differences in 2 regions.

CONCLUSIONS

Gadofosveset trisodium serves well for first-pass imaging in WB-MRA.

Multistation Whole-Body High-Spatial-Resolution MR Angiography Using a 32-Channel MR System

OBJECTIVE

The objective of our study was to investigate a multistation whole-body MR angiography (MRA) protocol using a 32-channel MR system with multicoil technology in a population of patients with suspected peripheral vascular disease (PVD).

SUBJECTS AND METHODS

Fifty consecutive patients with suspected PVD (31 men, 19 women; age range, 46-91 years) underwent multistation whole-body contrast-enhanced MR angiography (CE-MRA) on a 32-channel 1.5-T MR system equipped with multicoil technology. A two-step contrast injection protocol was used: After the first injection, images of the most proximal station (station I, head and neck) were acquired, followed by the most distal station (station IV, calves). Images of the intermediate two stations (station II, chest and abdomen; station III, pelvis and thighs) were acquired during the second injection. Conventional catheter angiography was performed for symptomatic vascular regions in 30 patients. The image quality of the arterial segments and the presence and degree of the arterial stenosis were evaluated by two radiologists. The interobserver variability was calculated by kappa statistics, and comparative analysis between CE-MRA and catheter angiography was performed by means of the Spearman's rank correlation coefficient.

RESULTS

Most of the vascular segments (1,912/1,976 [97%]) were visualized on wholebody CE-MRA with diagnostic image quality. Significant arterial disease (> or = 50%) was detected in 167 (observer 1) and 177 (observer 2) segments with excellent interobserver agreement (kappa = 0.84). There was a significant correlation between CE-MRA and conventional angiography for the degree of stenosis (R = 0.92 and 0.89 for observers 1 and 2, respectively). The sensitivity and specificity of CE-MRA for the detection of arterial stenoses 50% or greater were 92% and 96% for observer 1 and 93% and 97% for observer 2, respectively, compared with those of conventional angiography.

CONCLUSION

Using a multichannel radiofrequency system with multicoil technology, the whole-body CE-MRA approach outlined in this article is able to provide high-spatial-resolution data sets with high diagnostic image quality for evaluation of arterial occlusive disease in most vascular territories.

Gadobenate dimeglumine-enhanced MR angiography: Diagnostic performance of four doses for detection and grading of carotid, renal, and aorto-iliac stenoses compared to digital subtraction angiography

PURPOSE

To determine the diagnostic performance of contrast-enhanced MR angiography (CE-MRA) with four doses of gadobenate dimeglumine for detection of significant steno-occlusive disease of the carotid, renal, and pelvic vasculature.

MATERIALS AND METHODS

Eighty-four patients with suspected disease of the renal (n = 16), pelvic (n = 41), or carotid (n = 27) arteries underwent CE-MRA (3D-spoiled gradient-echo sequences) at 1.5T. CE-MRA was performed with gadobenate dimeglumine at 0.025, 0.05, 0.1, or 0.2 mmol/kg (23, 24, 19, and 18 patients, respectively) administered at 2 mL/sec. Accuracy, sensitivity, specificity, and positive and negative predictive values (PPV and NPV, respectively) for detection of significant disease (>50% stenosis or occlusion for renal/pelvic arteries; >70% stenosis or occlusion for carotid arteries) was determined by three fully blinded, independent radiologists using conventional digital subtraction angiography (DSA) as reference standard. All comparisons were tested statistically (ANOVA, chi-square, and Mantel-Haenszel tests as appropriate) and reader agreement (kappa) was assessed.

RESULTS

Values for accuracy, sensitivity, specificity, PPV, and NPV on CE-MRA were consistently higher for 0.1 mmol/kg gadobenate dimeglumine (accuracy = 95.2-97.3%, sensitivity = 84.2% (all readers), specificity = 96.9-99.2%, PPV = 80.0-94.1%, NPV = 97.6-97.7%). The greater accuracy of the 0.1 mmol/kg dose was significant (P < 0.01, all readers) compared to all other dose groups. Agreement between the three readers was good for all dose groups (kappa >/=0.58), with the highest percent agreement (85.7%) noted for the 0.1 mmol/kg dose.

CONCLUSION

Significantly better diagnostic performance on CE-MRA of the renal, pelvic, and carotid arteries is achieved with a gadobenate dimeglumine dose of 0.1 mmol/kg bodyweight.

Total-body 3D magnetic resonance angiography influences the management of patients with peripheral arterial occlusive disease

High-resolution total-body 3D MR angiography (MRA) has recently become available, revealing additional clinically relevant disease in patients with peripheral arterial occlusive disease (PAOD). However, the actual impact of total-body MRA on patient management in patients with PAOD has not been investigated so far. Two hundred forty-nine consecutive patients with angiographically proven PAOD were prospectively examined by means of contrast-enhanced total-body 3D MRA on a 1.5-T MR scanner. All correlative imaging studies performed within 60 days of total-body MRA were included in the efficacy analysis. Additional clinically relevant disease (luminal narrowing >50%, aneurysmal changes or dissections) was found in 73 segments (52 patients), including the renal arteries (36 segments), carotid arteries (28 segments), subclavian arteries (four segments) and abdominal aortic aneurysms (AAA) (five segments). Of the 73 segments, 36 were deemed necessary for further investigation by means of focused MRA examinations; the diagnosis was confirmed in all cases. Within the 60-day follow-up period, interventional or surgical therapy outside the peripheral arterial tree was performed in nine patients (11 segments), including carotid endatherectomy and renal artery angioplasty. The outlined total-body 3D MRA approach permits a comprehensive evaluation of the arterial system in patients with atherosclerosis and does indeed have an impact on patient management in patients with PAOD.

Three-dimensional contrast-enhanced MR angiography of the thoraco-abdominal vessels

With the strategies presented in this article,relevant disease involving the thoraco-abdominal vessels can be well depicted by 3D CEMRA. Aneurysms, dissections, occlusions, congenital lesions, and anatomic anomalies are readily assessed. Time-resolved MRA provides supplemental information in shunts, dissections, aneurysms, and AVMs. Velocity-encoded imaging may help fur-ther characterize lesions and may provide useful functional information to grade and monitor the progression of stenotic disease. 3.0T imaging and recent development in multicoil RF technology will further improve the performance of 3D CEMRAin terms of temporal and spatial resolution.

Myocardial infarct: depiction with contrast-enhanced MR imaging--comparison of gadopentetate and gadobenate

Institutional review board approval and patient written informed consent were obtained. On two separate occasions, 24 hours apart, contrast-enhanced cardiac magnetic resonance (MR) imaging was performed prospectively at 1, 3, 5, 10, and 20 minutes after injection of gadopentetate dimeglumine and gadobenate dimeglumine in 15 patients (11 men, four women) with history of myocardial infarction. Both agents allowed detection of infarcted myocardium. T1 values at all times were significantly (P < .05) lower for gadobenate, compared with values for gadopentetate, in both infarcted and noninfarcted myocardium. At 1 minute after administration of both agents, T1 values in left ventricular cavity (LVC) were not different; at 3-20 minutes after injection, values were significantly (P < .05) lower for gadobenate. Differences between contrast-to-noise ratio (CNR) values of infarcted and noninfarcted myocardium were significantly higher on gadobenate-enhanced images (P < .05). CNR values between infarcted myocardium and LVC were significantly higher on gadopentetate-enhanced images (P < .05). Gadopentetate might permit better delineation of infarcts, especially subendocardial infarcts.

Whole-body MR angiography using a novel 32-receiving-channel MR system with surface coil technology: first clinical experience

PURPOSE

To demonstrate the feasibility of detecting atherosclerotic vascular disease using an innovative magnetic resonance angiography (MRA) protocol in combination with a dedicated whole-body MR scanner with new surface coil technology.

MATERIALS AND METHODS

A total of 10 volunteers and eight patients with peripheral arterial occlusive disease (PAOD) were examined at 1.5 T. Conventional digital subtraction angiography (DSA) of the symptomatic region was available as a reference standard in all eight patients. Depending on subjects' size, four to five three-dimensional data sets were acquired using an adapted injection protocol. Images were assessed independently by two readers for vascular pathology. Additionally, signal-to-noise ratios (SNRs) and contrast-to-noise ratios (CNRs) were measured.

RESULTS

Whole-body MRA yielded excellent sensitivity and specificity of more than 95% for both readers with high interobserver agreement (k = 0.93). Surface coil signal reception rendered a high SNR (mean 151.28 +/- 54.04) and CNR (mean 120.75 +/- 46.47). Despite lower SNR and CNR of the cranial and cervical vessels, a two-step injection protocol exhibited less venous superposition and therefore proved to be superior compared to single-bolus injection.

CONCLUSION

Our approach provides accurate noninvasive high-resolution imaging of systemic atherosclerotic disease, covering the arterial vasculature from intracranial arteries to distal runoff vessels. The recently introduced MR scanner and coil technology is feasible to significantly increase the performance of whole-body MRA.

[Cardiovascular whole-body MRI: possibilities and limitations in prevention]

Cardiovascular disease is a major challenge to the healthcare with increasing prevalence in western societies. Hence, early detection of cardiovascular pathologies and preventative strategies will experience growing relevance in the future. Magnetic resonance imaging (MRI) nowadays allows a comprehensive analysis of the cardiovascular system. By combining separate examinations of brain, arterial vasculature, and heart the technique permits early detection of pathological changes with high diagnostic accuracy void of adverse events. Such a protocol has been proven feasible and technically robust and can be performed within 45 min. Inherent limitations are low spatial resolution of whole-body MR angiography and lack of functional stress testing of the heart. However, while being suitable as a fast and comprehensive imaging technique for cardiovascular screening purposes, medical consequences and socioeconomic relevance must further be elucidated.

Angiografia por ressonância magnética: aspectos técnicos de um método de estudo vascular não-invasivo

As primeiras técnicas de angiografia por ressonância magnética (angio-RM) utilizavam seqüências sensíveis ao fluxo sanguíneo para estabelecimento do contraste vascular. Há três técnicas fundamentadas neste princípio: contraste de fase ("phase-contrast"), TOF ("time-of-flight") e as técnicas de sangue escuro ("black blood"). Estas seqüências, de aquisição demorada, são mais suscetíveis a artefatos de movimento, perda de sinal em áreas de estenoses ou turbilhonamento de fluxo, e apresentam ainda baixa sensibilidade à detecção do fluxo lento. O uso do contraste paramagnético para estudos angiográficos pela ressonância magnética ofereceu um método simples, rápido e de excelente detalhamento vascular, baseando o contraste da imagem no realce do sinal vascular em oposição à supressão dos demais tecidos. Metodologias modernas que priorizam a obtenção do espaço k central, responsável pelo contraste da imagem, e o aperfeiçoamento das técnicas de planejamento do intervalo temporal para aquisição dos dados foram fatores fundamentais para o aprimoramento técnico da angio-RM. O papel atual da angio-RM como ferramenta diagnóstica merece destaque na avaliação de anomalias anatômicas, estenoses, oclusões e complicações vasculares pós-cirúrgicas, principalmente nos casos de transplantes de órgãos. Suas principais vantagens estão na não utilização do contraste iodado ou radiação ionizante, rapidez e fácil execução, mínima invasividade e possibilidade de avaliar complementarmente o parênquima de órgãos adjacentes de interesse diagnóstico.

Gadobenate dimeglumine (MultiHance®) for magnetic resonance angiography: review of literature

Although limited in number, reports describing the use of Gd-BOPTA for 3D CE-MRA reveal that this agent is safe, well tolerated and effective for CE-MRA at doses up to 0.3 mmol/kg bodyweight. The use of Gd-BOPTA leads to additional diagnostically relevant information comparable to that attainable with conventional DSA and superior to that on non-enhanced MRA in most arterial territories. In studies in which Gd-BOPTA is compared at equal dose with other gadolinium-based MR contrast agents, Gd-BOPTA has consistently shown significantly better quantitative and qualitative performance. Thus, Gd-BOPTA can be considered to have a very favorable risk/benefit ratio for MRA. In summary, it is likely the documented superiority of Gd-BOPTA for MR angiography will lead to its broad usage for this indication wherever the agent becomes available.

Gadobenate dimeglumine-enhanced magnetic resonance angiography of the pelvic arteries

RATIONALE AND OBJECTIVES

To evaluate 4 doses of gadobenate dimeglumine (Gd-BOPTA) for contrast-enhanced magnetic resonance angiography (CE-MRA) of the pelvic arteries and to compare CE-MRA with unenhanced time-of-flight MRA (2D-TOF-MRA).

METHODS

A multicenter Phase II dose-finding study was performed in 136 patients with Gd-BOPTA doses of 0.025, 0.05, 0.1, and 0.2 mmol/kg bodyweight. Evaluation of CE-MRA images and comparison with 2D-TOF-MRA images was performed onsite and by 2 blinded offsite reviewers in terms of subjective image quality, number of lesions detected, and confidence in lesion characterization.

RESULTS

Significant (P < 0.05) improvements over unenhanced findings were observed for CE-MRA at all dose levels. For reviewer 1 and the onsite investigators, the overall image quality increased up to a dose of 0.1 mmol/kg and then plateaued. For reviewer 2, increased image quality was noted up to a dose of 0.2 mmol/kg. Significant (P < 0.005) increases in diagnostic confidence on CE-MRA versus unenhanced MRA was observed for all dose groups by reviewer 1 and the onsite investigators and for the 0.1 and 0.2 mmol/kg dose groups by reviewer 2. No serious adverse events were recorded that were attributable to the study drug and no trends in laboratory parameters, vital signs, or electrocardiogram recordings were observed.

CONCLUSIONS

Gadobenate dimeglumine-enhanced MRA is safe and significantly more effective than unenhanced 2D-TOF-MRA for imaging the pelvic arteries. A dose of 0.1 mmol/kg appears the most appropriate dose for subsequent Phase III clinical evaluation.

Contrast-enhanced MR angiography of the run-off vasculature: intraindividual comparison of gadobenate dimeglumine with gadopentetate dimeglumine

PURPOSE

To compare intraindividually gadobenate dimeglumine (Gd-BOPTA) with gadopentetate dimeglumine (Gd-DTPA) for multi-station MR Angiography of the run-off vessels.

MATERIALS AND METHODS

Twenty-one randomized healthy volunteers received either Gd-BOPTA or Gd-DTPA as a first injection and then the other agent as a second injection after a minimum interval of 6 days. Each agent was administered at a dose of 0.1 mmol/kg bodyweight followed by a 25-mL saline flush at a single constant flow rate of 0.8 mL/second. Images were acquired sequentially at the level of the pelvis, thigh, and calf using a fast three-dimensional (3D) gradient echo sequence. Source, subtracted source, maximum intensity projection (MIP), and subtracted MIP image sets from each examination were evaluated quantitatively and qualitatively on a segmental basis involving nine vascular segments.

RESULTS

Significantly (P < 0.05) higher signal-to-noise and contrast-to-noise ratios were noted for Gd-BOPTA compared to Gd-DTPA, with the more pronounced differences evident in the more distal vessels. Qualitative assessmentrevealed no differences in the abdominal vasculature, a preference for Gd-BOPTA in the pelvic vasculature, and markedly better performance for Gd-BOPTA in the femoral and tibial vasculature. Summation of individual diagnostic quality scores for each segment revealed a significantly (P = 0.0001) better performance for Gd-BOPTA compared to Gd-DTPA.

CONCLUSION

Greater vascular enhancement of the run-off vasculature is obtained after Gd-BOPTA, particularly in the smaller more distal vessels. Enhancement differences are not merely dose dependent, but may be due to different vascular enhancement characteristics of the agents.

Using a 1 M Gd-chelate (gadobutrol) for total-body three-dimensional MR angiography: preliminary experience

PURPOSE

To determine whether higher concentrated gadolinium chelates are advantageous for the recently introduced concept of total-body magnetic resonance angiography (MRA), allowing whole-body coverage, extending from the carotid arteries to the runoff vessels, in merely 72 seconds.

MATERIALS AND METHODS

Total-body three-dimensional (3D) MRA using a 1 M Gd-chelate (gadobutrol, Gadovist, Schering, Berlin, Germany) at a dosage of 0.2 mmol/kg body-weight (biphasic injection protocol: 1.3 mL/second and 0.7 mL/second) was performed on three healthy volunteers and ten consecutive patients with DSA-documented peripheral vascular disease. Separated by at least 72 hours, the three healthy volunteers also underwent the same MRA-protocol, using gadopentetate dimeglumine in equimolar dosages.

RESULTS

Compared to equimolar dosages, mean signal-to-noise ratio (SNR) and contrast-to-noise ratio (CNR) values in the three volunteers were significantly higher (up to 32.5% for the arteries of the thighs and calves) using gadobutrol. In the ten patients, gadobutrol-based total-body MRA accurately assessed significant stenoses (luminal narrowing > 50%) with sensitivities and specificities of 96.2% (95% CI 0.83-0.97) and 95.7% (95% CI 0.84-0.96), respectively, compared to digital subtraction angiography.

CONCLUSION

The MRA image quality for total-body MRA provided by the administration of gadobutrol is superior to that obtained following administration of an identical dose of gadopentetate dimeglumine, and therefore shows promise for use as a comprehensive single exam assessing the entire arterial system for the presence of atherosclerotic disease manifestations.

Detection of atherosclerosis: systemic imaging for systemic disease with whole-body three-dimensional MR angiography--initial experience

In 100 consecutive patients with peripheral vascular disease whole-body three-dimensional magnetic resonance (MR) angiography was performed by using the rolling table platform system with a 1.5-T MR unit and five three-dimensional MR angiographic data sets during 72 seconds (0.2 mol per kilogram of body weight of gadobenate dimeglumine). Apart from the proved peripheral vascular disease, additional clinically relevant disease was found in 33 segments in 25 patients as follows: renal arterial narrowing (n = 15), carotid arterial stenosis (n = 12), subclavian arterial stenosis (n = 2), and abdominal aortic aneurysms (n = 4). Confirmatory studies performed in 11 patients in this study revealed no false-positive or false-negative findings at examination.

Intraindividual comparison of gadopentetate dimeglumine, gadobenate dimeglumine, and gadobutrol for pelvic 3D magnetic resonance angiography

RATIONALE AND OBJECTIVES

To compare the effect on image quality of a 1.0 mol/L gadolinium chelate with that of two 0.5 mol/L gadolinium compounds.

MATERIALS AND METHODS

Five healthy volunteers underwent a mono-station 3D MRA exam (Siemens SONATA, Erlangen, Germany) four times using four separate gadolinium preparations. All subjects first received a fixed volume of undiluted gadobutrol (1 mol/L), which corresponded to a dose between 0.1 and 0.15 mmol/kg body weight. This gadobutrol dosage was then diluted with saline into twice the volume and administered as a bolus at twice the injection rate. For Gd-DTPA and Gd BOPTA, because these contrast agents are 0.5 mol/L preparations, the volume and flow rate were doubled to match diluted gadobutrol volume and concentration. Quantitative and qualitative analysis of the angiographic data sets was performed on nine arterial segments.

RESULTS

Image quality was rated diagnostic for all image data sets without statistically significant differences between any of the compounds (P > 0.3). Quantitative measurements of Gd BOPTA (SNR: 81.15; CNR: 68.91) and both standard and diluted forms of gadobutrol (SNR: 84.33; CNR: 71.62; SNR(diluted): 79,23; CNR(diluted): 66.26) yielded significantly higher results (P < 0.02) in comparison with Gd-DTPA (SNR: 49.55; CNR: 38.24). The difference between either form of gadobutrol and Gd BOPTA was not shown to be statistically significant (P > 0.3), whereas both the SNR and CNR of standard gadobutrol were significantly higher than diluted gadobutrol.

CONCLUSION

Gadobutrol- and Gd BOPTA-MRA exams lead to improved delineation of the pelvic arterial morphology compared with MRA exams performed with Gd-DTPA.

Assessment of gadobenate dimeglumine for magnetic resonance angiography: phase I studies

RATIONALE AND OBJECTIVES

To assess the vascular contrasting properties of a new MR contrast agent (gadobenate dimeglumine [Gd-BOPTA]), which presents higher relaxivity because of reversible, weak protein interaction, and, to compare these properties with a standard gadolinium agent.

MATERIALS AND METHODS

Two phase I trials compared intraindividually: (A) the vascular contrasting properties of Gd-BOPTA at three doses (0.0125, 0.05, and 0.2 mmol/kg body weight) and two flow rates (0.5 and 2.0 mL/s) in 10 volunteers; and (B) 0.1 mmol/kg body weight doses of Gd-BOPTA and Gd-DTPA at 2.0 mL/s using a modified magnetic resonance angiography (MRA) sequence with a temporal resolution of 1 s/f. Quantitative (ROI analysis) and fully blinded qualitative (reader review) assessment of images was performed.

RESULTS

A dose of 0.2 mmol/kg resulted in higher maximum intensities, longer median peak widths, and larger areas under the curve than did the lower doses (0.0125 mmol/kg and 0.05 mmol/kg). In the intraindividual comparison, Gd-BOPTA demonstrated significantly better vascular enhancement characteristics in terms of signal peak duration (p < 0.05), maximum signal intensity (p < 0.05), and area under the enhancement curve (p < 0.01). The multireader assessment for overall vascular contrast preferred Gd-BOPTA at p < 0.03.

CONCLUSIONS

Gd-BOPTA was shown to exhibit preferential and different vascular enhancement properties as compared with Gd-DTPA for MRA.