Intra-individual, randomised comparison of the MRI contrast agents gadobutrol versus gadoteridol in patients with primary and secondary brain tumours, evaluated in a blinded read

Evolving Characteristics of Gadolinium-Based Contrast Agents for MR Imaging: A Systematic Review of the Importance of Relaxivity

Gadolinium-based contrast agents (GBCAs) are widely and routinely used to enhance the diagnostic performance of magnetic resonance imaging and magnetic resonance angiography examinations. T1 relaxivity (r1) is the measure of their ability to increase signal intensity in tissues and blood on T1-weighted images at a given dose. Pharmaceutical companies have invested in the design and development of GBCAs with higher and higher T1 relaxivity values, and "high relaxivity" is a claim frequently used to promote GBCAs, with no clear definition of what "high relaxivity" means, or general concurrence about its clinical benefit. To understand whether higher relaxivity values translate into a material clinical benefit, well-designed, and properly powered clinical studies are necessary, while mere in vitro measurements may be misleading. This systematic review of relevant peer-reviewed literature provides high-quality clinical evidence showing that a difference in relaxivity of at least 40% between two GBCAs results in superior diagnostic efficacy for the higher-relaxivity agent when this is used at the same equimolar gadolinium dose as the lower-relaxivity agent, or similar imaging performance when used at a lower dose. Either outcome clearly implies a relevant clinical benefit. LEVEL OF EVIDENCE: 2 TECHNICAL EFFICACY: Stage 3.

The feasibility of half-dose contrast-enhanced scanning of brain tumours at 5.0 T: a preliminary study

PURPOSE

This study investigated and compared the effects of Gd enhancement on brain tumours with a half-dose of contrast medium at 5.0 T and with a full dose at 3.0 T.

METHODS

Twelve subjects diagnosed with brain tumours were included in this study and underwent MRI after contrast agent injection at 3.0 T (full dose) or 5.0 T (half dose) with a 3D T1-weighted gradient echo sequence. The postcontrast images were compared by two independent neuroradiologists in terms of the signal-to-noise ratio (SNR), contrast-to-noise ratio (CNR) and subjective image quality score on a ten-point Likert scale. Quantitative indices and subjective quality ratings were compared with paired Student's t tests, and interreader agreement was assessed with the intraclass correlation coefficient (ICC).

RESULTS

A total of 16 enhanced tumour lesions were detected. The SNR was significantly greater at 5.0 T than at 3.0 T in grey matter, white matter and enhanced lesions (p < 0.001). The CNR was also significantly greater at 5.0 T than at 3.0 T for grey matter/tumour lesions, white matter/tumour lesions, and grey matter/white matter (p < 0.001). Subjective evaluation revealed that the internal structure and outline of the tumour lesions were more clearly displayed with a half-dose at 5.0 T (Likert scale 8.1 ± 0.3 at 3.0 T, 8.9 ± 0.3 at 5.0 T, p < 0.001), and the effects of enhancement in the lesions were comparable to those with a full dose at 3.0 T (7.8 ± 0.3 at 3.0 T, 8.7 ± 0.4 at 5.0 T, p < 0.001). All subjective scores were good to excellent at both 5.0 T and 3.0 T.

CONCLUSION

Both quantitative and subjective evaluation parameters suggested that half-dose enhanced scanning via 5.0 T MRI might be feasible for meeting clinical diagnostic requirements, as the image quality remains optimal. Enhanced scanning at 5.0 T with a half-dose of contrast agents might benefit patients with conditions that require less intravenous contrast agent, such as renal dysfunction.

The TRUTH confirmed: validation of an intraindividual comparison of gadobutrol and gadoteridol for imaging of glioblastoma using quantitative enhancement analysis

BACKGROUND

Previous intraindividual comparative studies evaluating gadobutrol and gadoteridol for contrast-enhanced magnetic resonance imaging (MRI) of brain tumours have relied on subjective image assessment, potentially leading to misleading conclusions. We used artificial intelligence algorithms to objectively compare the enhancement achieved with these contrast agents in glioblastoma patients.

METHODS

Twenty-seven patients from a prior study who received identical doses of 0.1 mmol/kg gadobutrol and gadoteridol (with appropriate washout in between) were evaluated. Quantitative enhancement (QE) maps of the normalised enhancement of voxels, derived from computations based on the comparison of contrast-enhanced T1-weighted images relative to the harmonised intensity on unenhanced T1-weighted images, were compared. Bland-Altman analysis, linear regression analysis and Pearson correlation coefficient (r) determination were performed to compare net QE and per-region of interest (per-ROI) average QE (net QE divided by the number of voxels).

RESULTS

No significant differences were observed for comparisons performed on net QE (mean difference -24.37 ± 620.8, p = 0.840, r = 0.989) or per-ROI average QE (0.0043 ± 0.0218, p = 0.313, r = 0.958). Bland-Altman analysis revealed better per-ROI average QE for gadoteridol-enhanced MRI in 19/27 (70.4%) patients although the mean difference (0.0043) was close to zero indicating high concordance and the absence of fixed bias.

CONCLUSIONS

The enhancement of glioblastoma achieved with gadoteridol and gadobutrol at 0.1 mmol/kg bodyweight is similar indicating that these agents have similar contrast efficacy and can be used interchangeably, confirming the results of a prior double-blind, randomised, intraindividual, crossover study.

Comparison of Dynamic Contrast-Enhancement Parameters between Gadobutrol and Gadoterate Meglumine in Posttreatment Glioma: A Prospective Intraindividual Study

BACKGROUND AND PURPOSE

Differences in molecular properties between one-molar and half-molar gadolinium-based contrast agents are thought to affect parameters obtained from dynamic contrast-enhanced imaging. The aim of our study was to investigate differences in dynamic contrast-enhanced parameters between one-molar nonionic gadobutrol and half-molar ionic gadoterate meglumine in patients with posttreatment glioma.

MATERIALS AND METHODS

This prospective study enrolled 32 patients who underwent 2 20-minute dynamic contrast-enhanced examinations, one with gadobutrol and one with gadoterate meglumine. The model-free parameter of area under the signal intensity curve from 30 to 1100 seconds and the Tofts model-based pharmacokinetic parameters were calculated and compared intraindividually using paired t tests. Patients were further divided into progression (n = 12) and stable (n = 20) groups, which were compared using Student t tests.

RESULTS

Gadobutrol and gadoterate meglumine did not show any significant differences in the area under the signal intensity curve or pharmacokinetic parameters of K ^trans, V_e, V_p, or K_ep (all P > .05). Gadobutrol showed a significantly higher mean wash-in rate (0.83 ± 0.64 versus 0.29 ± 0.63, P = .013) and a significantly lower mean washout rate (0.001 ± 0.0001 versus 0.002 ± 0.002, P = .02) than gadoterate meglumine. Trends toward higher area under the curve, K ^trans, V_e, V_p, wash-in, and washout rates and lower K_ep were observed in the progression group in comparison with the treatment-related-change group, regardless of the contrast agent used.

CONCLUSIONS

Model-free and pharmacokinetic parameters did not show any significant differences between the 2 gadolinium-based contrast agents, except for a higher wash-in rate with gadobutrol and a higher washout rate with gadoterate meglumine, supporting the interchangeable use of gadolinium-based contrast agents for dynamic contrast-enhanced imaging in patients with posttreatment glioma.

Diagnostic efficacy and safety of gadoteridol compared to gadobutrol and gadoteric acid in a large sample of CNS MRI studies at 1.5T

PURPOSE

To evaluate safety and diagnostic accuracy of gadoteridol vs. other macrocyclic gadolinium-based contrast agents (GBCAs) in a large cohort of consecutive and non-selected patients referred for CE-MRI of the CNS.

MATERIAL AND METHODS

Between November 2017 and March 2018, we prospectively enrolled a consecutive cohort of patients referred for neuroradiological CE-MRI (1.5T MRI). Image quality and adverse events were assessed. Diagnostic performance was determined for a subgroup of patients with truth standard findings available. Comparison was made between patients receiving gadoteridol and patients receiving other macrocyclic GBCAs. Inter-reader agreement (kappa) between two expert neuroradiologists was calculated for the diagnosis of malignancy.

RESULTS

Overall, 460 patients (220M/240F; mean age 54±16 years) were enrolled of which 230 received gadoteridol (Group 1) and 230 either gadoteric acid or gadobutrol [n=83 (36.1%) and n=147 (63.9%), respectively; Group 2]. Image quality was rated as good or excellent in both groups. The sensitivity, specificity and diagnostic accuracy for determination of malignancy was 88.2%, 96.5% and 95.4%, respectively, for Group 1 and 93.7%, 97.4% and 96.9%, respectively, for Group 2, with no significant differences between groups (P>0.75) for any determination. Inter-reader agreement for the identification of malignancy was excellent [K=0.877 (95%CI: 0.758-0.995) and K=0.818 (95%CI: 0.663-0.972) for groups 1 and 2, respectively; P=0.0913]. Adverse events occurred in 5 of 460 (1.09%) patients overall, with no significant difference (P=0.972) between groups.

CONCLUSION

Gadoteridol was safe and guaranteed good image quality without significant differences when compared to gadobutrol and gadoteric acid in a wide range of CNS pathologies.

Inter-individual Comparison of Gadobutrol and Gadoteridol Tissue Time-intensity Profiles for Dynamic Susceptibility Contrast Perfusion MR Imaging

Purpose:

Gadobutrol is a gadolinium-based contrast material (GBCM) with a high concentration of gadolinium and high relaxivity. Our purpose was to evaluate the signal intensity profiles in brain tissue for the bolus width and degree of signal change after bolus injection using an echo planar dynamic susceptibility contrast (DSC) sequence. We compared gadobutrol to gadoteridol using various injection speeds and saline flush volumes.

Methods:

We studied 97 patients who underwent brain MRI. Datasets for perfusion studies were acquired using a 3T scanner with an echo planar imaging (EPI) sequence. The injection protocols were set up with combinations of injection speed and saline flush volume for both gadobutrol and gadoteridol. The full width at half maximum (FWHM) and the maximum signal change ratio (SCR_max ) of the time intensity curves were measured.

Results:

The FWHM did not show a statistically significant difference according to injection speed, flush volume, or type of GBCM. The SCR_max showed a greater change with a faster injection speed, larger saline flush, and gadobutrol administration. The difference between gadobutrol and gadoteridol became smaller with a faster injection speed and a larger saline flush.

Conclusion:

The maximum signal drop was larger with gadobutrol when the injection speed was slow and the saline flush was small. Thus, gadobutrol may be useful to obtain a better profile for DSC perfusion MRI in conditions requiring a slower injection speed and/or a smaller volume of saline flush.

Comparison of normal facial nerve enhancement at 3T MRI using gadobutrol and gadopentetate dimeglumine

Background and purpose The facial nerve is unique among cranial nerves in demonstrating normal enhancement of particular segments. The effect of varying T1 relaxivities of gadolinium-based contrast agents on facial nerve enhancement is unclear. In this study, we assess differences in normal facial nerve enhancement with two different gadolinium-based contrast agents, gadobutrol and gadopentetate dimeglumine. In addition, we evaluate differences in facial nerve enhancement with spin-echo (SE) T1 versus 3D inversion recovery prepared fast spoiled gradient-echo (FSPGR) post-contrast sequences. Methods A total of 140 facial nerves in 70 individuals were evaluated (70 with gadobutrol and 70 with gadopentetate dimeglumine) by two blinded reviewers. Differences in enhancement of facial nerve segments between the two agents were analyzed. Differences in enhancement between SE T1 and FSPGR imaging were also evaluated. Results There was no significant difference in facial nerve enhancement between gadobutrol and gadopentetate dimeglumine. Enhancement was commonly observed in the geniculate, tympanic and mastoid segments (98%-100%) with either contrast agent; enhancement was less common in the labyrinthine segments (9%-14%) and lateral canalicular segment (2%-5%). There was a smaller enhancing proportion of labyrinthine and tympanic segments with FSPGR as compared to SE T1 images with gadobutrol. Conclusion There is no significant difference in overall enhancement of the facial nerve between gadobutrol and gadopentetate dimeglumine. Mild enhancement of the lateral canalicular portion of the facial nerve may be a normal finding. With FSPGR sequence, there is lesser perceived enhancement of the labyrinthine and tympanic segments of the facial nerve with gadobutrol.

25 Years of Contrast-Enhanced MRI: Developments, Current Challenges and Future Perspectives

In 1988, the first contrast agent specifically designed for magnetic resonance imaging (MRI), gadopentetate dimeglumine (Magnevist(®)), became available for clinical use. Since then, a plethora of studies have investigated the potential of MRI contrast agents for diagnostic imaging across the body, including the central nervous system, heart and circulation, breast, lungs, the gastrointestinal, genitourinary, musculoskeletal and lymphatic systems, and even the skin. Today, after 25 years of contrast-enhanced (CE-) MRI in clinical practice, the utility of this diagnostic imaging modality has expanded beyond initial expectations to become an essential tool for disease diagnosis and management worldwide. CE-MRI continues to evolve, with new techniques, advanced technologies, and novel contrast agents bringing exciting opportunities for more sensitive, targeted imaging and improved patient management, along with associated clinical challenges. This review aims to provide an overview on the history of MRI and contrast media development, to highlight certain key advances in the clinical development of CE-MRI, to outline current technical trends and clinical challenges, and to suggest some important future perspectives.

FUNDING

Bayer HealthCare.

The Benefits of High Relaxivity for Brain Tumor Imaging: Results of a Multicenter Intraindividual Crossover Comparison of Gadobenate Dimeglumine with Gadoterate Meglumine (The BENEFIT Study)

BACKGROUND AND PURPOSE

Gadobenate dimeglumine (MultiHance) has higher r1 relaxivity than gadoterate meglumine (Dotarem) which may permit the use of lower doses for MR imaging applications. Our aim was to compare 0.1- and 0.05-mmol/kg body weight gadobenate with 0.1-mmol/kg body weight gadoterate for MR imaging assessment of brain tumors.

MATERIALS AND METHODS

We performed crossover, intraindividual comparison of 0.1-mmol/kg gadobenate with 0.1-mmol/kg gadoterate (Arm 1) and 0.05-mmol/kg gadobenate with 0.1-mmol/kg gadoterate (Arm 2). Adult patients with suspected or known brain tumors were randomized to Arm 1 (70 patients) or Arm 2 (107 patients) and underwent 2 identical examinations at 1.5 T. The agents were injected in randomized-sequence order, and the 2 examinations were separated by 2-14 days. MR imaging scanners, imaging sequences (T1-weighted spin-echo and T1-weighted high-resolution gradient-echo), and acquisition timing were identical for the 2 examinations. Three blinded readers evaluated images for diagnostic information (degree of definition of lesion extent, lesion border delineation, visualization of lesion internal morphology, contrast enhancement) and quantitatively for percentage lesion enhancement and lesion-to-background ratio. Safety assessments were performed.

RESULTS

In Arm 1, a highly significant superiority (P < .002) of 0.1-mmol/kg gadobenate was demonstrated by all readers for all end points. In Arm 2, no significant differences (P > .1) were observed for any reader and any end point, with the exception of percentage enhancement for reader 2 (P < .05) in favor of 0.05-mmol/kg gadobenate. Study agent-related adverse events were reported by 2/169 (1.2%) patients after gadobenate and by 5/175 (2.9%) patients after gadoterate.

CONCLUSIONS

Significantly superior morphologic information and contrast enhancement are demonstrated on brain MR imaging with 0.1-mmol/kg gadobenate compared with 0.1-mmol/kg gadoterate. No meaningful differences were recorded between 0.05-mmol/kg gadobenate and 0.1-mmol/kg gadoterate.

MRI in multiple sclerosis: an intra-individual, randomized and multicentric comparison of gadobutrol with gadoterate meglumine at 3 T

OBJECTIVES

To compare contrast effects of gadobutrol with gadoterate meglumine for brain MRI in multiple sclerosis (MS) in a multicentre, randomized, prospective, intraindividual study at 3 T.

METHODS

Institutional review board approval was obtained. Patients with known or suspected active MS lesions were included. Two identical MRIs were performed using randomized contrast agent order. Four post-contrast T1 sequences were acquired (start time points 0, 3, 6 and 9 min). If no enhancing lesion was present in first MRI, second MRI was cancelled. Quantitative (number and signal intensity of enhancing lesions) and qualitative parameters (time points of first and all lesions enhancing; subjective preference regarding contrast enhancement and lesion delineation; global preference) were evaluated blinded.

RESULTS

Seventy-four patients (male, 26; mean age, 35 years) were enrolled in three centres. In 45 patients enhancing lesions were found. Number of enhancing lesions increased over time for both contrast agents without significant difference (median 2 for both). Lesions signal intensity was significantly higher for gadobutrol (p < 0.05 at time points 3, 6 and 9 min). Subjective preference rating showed non-significant tendency in favour of gadobutrol.

CONCLUSION

Both gadobutrol and gadoterate meglumine can be used for imaging of acute inflammatory MS lesions. However, gadobutrol generates higher lesion SI.

KEY POINTS

Contrast-enhanced MRI plays a key role in the management of multiple sclerosis. Different gadolinium-based contrast agents are available. Number of visibly enhancing lesions increases over time after contrast injection. Gadobutrol and gadoterate meglumine do not differ in number of visible lesions. Gadobutrol generates higher signal intensity than gadoterate meglumine.

Are there differences between macrocyclic gadolinium contrast agents for brain tumor imaging? Results of a multicenter intraindividual crossover comparison of gadobutrol with gadoteridol (the TRUTH study)

BACKGROUND AND PURPOSE

Gadobutrol (Gadavist) and gadoteridol (ProHance) have similar macrocyclic molecular structures, but gadobutrol is formulated at a 2-fold higher (1 mol/L versus 0.5 mol/L) concentration. We sought to determine whether this difference impacts morphologic contrast-enhanced MR imaging.

MATERIALS AND METHODS

Two hundred twenty-nine adult patients with suspected or known brain tumors underwent two 1.5T MR imaging examinations with gadoteridol or gadobutrol administered in randomized order at a dose of 0.1 mmol/kg of body weight. Imaging sequences and T1 postinjection timing were identical for both examinations. Three blinded readers evaluated images qualitatively and quantitatively for lesion detection and for accuracy in characterization of histologically confirmed brain tumors. Data were analyzed by using the Wilcoxon signed rank test, the McNemar test, and a mixed model.

RESULTS

Two hundred nine patients successfully completed both examinations. No reader noted a significant qualitative or quantitative difference in lesion enhancement, extent, delineation, or internal morphology (P values = .69-1.00). One hundred thirty-nine patients had at least 1 histologically confirmed brain lesion. Two readers found no difference in the detection of patients with lesions (133/139 versus 135/139, P = .317; 137/139 versus 136/139, P = .564), while 1 reader found minimal differences in favor of gadoteridol (136/139 versus 132/139, P = .046). Similar findings were noted for the number of lesions detected and characterization of tumors (malignant/benign). Three-reader agreement for characterization was similar for gadobutrol (66.4% [κ = 0.43]) versus gadoteridol (70.3% [κ = 0.45]). There were no significant differences in the incidence of adverse events (P = .199).

CONCLUSIONS

Gadoteridol and gadobutrol at 0.1 mmol/kg of body weight provide similar information for visualization and diagnosis of brain lesions. The 2-fold higher gadolinium concentration of gadobutrol provides no benefit for routine morphologic imaging.

Gadolinium contrast agents for CNS imaging: current concepts and clinical evidence

SUMMARY

The aim of this article was to review the properties of the various gadolinium-based contrast agents used for CNS imaging along with the clinical evidence and published data that highlight the impact these different properties can have on diagnostic performance. In addition, approaches to optimizing image acquisition that take into account the different properties of specific gadolinium-based contrast agents and an extensive review of the safety profiles of the various agents are presented.