No Cases of Nephrogenic Systemic Fibrosis after Administration of Gadoxetic Acid

MRI contrast agents and retention in the brain: review of contemporary knowledge and recommendations to the future

Gadolinium-based contrast agents (GBCA) were introduced with high expectations for favorable efficacy, low nephrotoxicity, and minimal allergic-like reactions. Nephrogenic systemic fibrosis and proven gadolinium retention in the body including the brain has led to the restriction of linear GBCAs and a more prudent approach regarding GBCA indication and dosing. In this review, we present the chemical, physical, and clinical aspects of this topic and aim to provide an equanimous and comprehensive summary of contemporary knowledge with a perspective of the future. In the first part of the review, we present various elements and compounds that may serve as MRI contrast agents. Several GBCAs are further discussed with consideration of their relaxivity, chelate structure, and stability. Gadolinium retention in the brain is explored including correlation with the presence of metalloprotein ferritin in the same regions where visible hyperintensity on unenhanced T1-weighted imaging occurs. Proven interaction between ferritin and gadolinium released from GBCAs is introduced and discussed, as well as the interaction of other elements with ferritin; and manganese in patients with impaired liver function or calcium in Fahr disease. We further present the concept that only high-molecular-weight forms of gadolinium can likely visibly change signal intensity on unenhanced T1-weighted imaging. Clinical data are also presented with respect to potential neurological manifestations originating from the deep-brain nuclei. Finally, new contrast agents with relatively high relaxivity and stability are introduced. CRITICAL RELEVANCE STATEMENT: GBCA may accumulate in the brain, especially in ferritin-rich areas; however, no adverse neurological manifestations have been detected in relation to gadolinium retention. KEY POINTS: Gadolinium currently serves as the basis for MRI contrast agents used clinically. No adverse neurological manifestations have been detected in relation to gadolinium retention. Future contrast agents must advance chelate stability and relativity, facilitating lower doses.

MR Angiography of Pulmonary Vasculature

Pulmonary MR angiography (MRA) is a useful alternative to computed tomographic angiography (CTA) for the study of the pulmonary vasculature. For pulmonary hypertension and partial anomalous pulmonary venous return, a cardiac MR imaging and the pulmonary MRA are useful for flow quantification and planning treatment. For the diagnosis of pulmonary embolism (PE), MRA-PE has been shown to have non-inferior outcomes at 6 months when compared with CTA-PE. Over the last 15 years, pulmonary MRA has become a routine and reliable examination for the workup of pulmonary hypertension and the primary diagnosis of PE at the University of Wisconsin.

Abbreviated MRI with second shot arterial phase for HCC evaluation: modified version of LI-RADS and recall reduction strategy

OBJECTIVES

To evaluate the feasibility of simulated abbreviated MRI (AMRI) with second shot arterial phase (SSAP) for HCC surveillance and diagnosis.

METHODS

A total of 129 consecutive patients (age, 58.8 ± 11.4 years; male, 71.3%) underwent gadoxetic acid-enhanced MRI using a modified injection protocol for HCC evaluation from July 2017 to February 2018. The modified injection protocol consisted of routine dynamic imaging (6 mL) and SSAP imaging (4 mL). Two radiologists independently reviewed two AMRI sets: AMRI without SSAP (surveillance set) and AMRI with SSAP (diagnosis set). A modified version of the Liver Imaging Reporting and Data System (LI-RADS) for the diagnosis set was devised by referring to contrast-enhanced ultrasound LI-RADS.

RESULTS

Sixty-seven patients with HCC and 62 patients without HCC were included. In the surveillance set, sensitivity and specificity for the detection of patients with HCC were 95.5% and 96.8%, and 94.0% and 96.8% in reviewers 1 and 2, respectively. In the diagnosis set, the scores of most HCCs (76/78, 97.4%) were consistent between LI-RADS of full-protocol and modified LI-RADS of AMRI with SSAP protocol. When the HCC surveillance and diagnosis strategy was changed from strategy 1 (AMRI without SSAP) to strategy 2 (AMRI with SSAP), the recall rate significantly decreased from 52.7 to 3.9% (p < 0.001).

CONCLUSIONS

The modified LI-RADS score of the AMRI with SSAP protocol showed high agreement with the LI-RADS score of the full protocol. The HCC surveillance and diagnosis strategy using the AMRI with SSAP protocol reduced the recall rate. These results may enable to diagnose HCC simultaneously with surveillance.

KEY POINTS

• A modified version of LI-RADS was devised for the diagnostic algorithm using AMRI with the second shot arterial phase (SSAP) by referring to CEUS LI-RADS. • The modified LI-RADS scores using AMRI with SSAP showed a high concordance rate with the conventional LI-RADS score using full-protocol MRI. • The recall rate significantly decreased when the HCC surveillance and diagnosis strategy was changed from strategy 1 (AMRI without SSAP; surveillance then recall test) to strategy 2 (AMRI with SSAP; simultaneous surveillance and diagnosis).

Gadolinium-Based Contrast Agents: Updates and Answers to Typical Questions Regarding Gadolinium Use

Gadolinium-based contrast agents have expanded the diagnostic usefulness and capability of magnetic resonance imaging. Despite their highly favorable safety profile, these agents have been associated with nephrogenic systemic fibrosis in a small number of patients who have advanced kidney disease. Recently, trace amounts of gadolinium deposition in the brain and other organs have been reported after contrast exposure, even in patients with normal renal function. In this review, we provide a brief overview of recent updates and discuss typical clinical situations related to the use of gadolinium-based contrast agents.

Risk of nephrogenic systemic fibrosis (NSF) in oncology patients receiving gadoxetic acid and updated risk of estimate of NSF in patients receiving gadoxetic acid with moderate and severe renal impairment

OBJECTIVES

Gadoxetic acid (GA) is a half-biliary excreted gadolinium-based contrast agent (GBCA) administered at lower dose than gadobenic acid with similar ionic structure. Gadobenic acid is considered low-risk for nephrogenic systemic fibrosis (NSF) in patients with impaired renal function; however, safety of GA is unclear. The objective of this study was to determine the incidence of NSF in oncology patients undergoing GA-enhanced MRI and to update the risk estimate of NSF in patients receiving GA with severe renal impairment.

MATERIALS AND METHODS

We retrospectively identified GA-enhanced MRI performed for treatment planning in confirmed cancer patients between March 2011 and December 2020. Serum creatinine values within 180 days of GA administration were retrieved and estimated glomerular filtration rate (eGFR) calculated. The eGFR value nearest to each MRI examination was used. The search result was linked to a prospectively maintained registry of reported cases of NSF. An updated literature review was conducted to identify published cases of NSF related to GA administration in patients with severe renal impairment (eGFR < 30 mL/min/1.73 m² or on dialysis) and the incidence of NSF with 95% confidence intervals (CI) was determined combining published data with our results.

RESULTS

192 oncology patients underwent GA-enhanced MRI, mean age was 65.6 ± 11.8 years with 73 women. The mean eGFR was 89.6 ± 33.0 mL/min/1.73 m². There were 33 patients with moderate (eGFR 30-60 mL/min/1.73 m²) and 1 patient with severe (eGFR < 30 mL/min/1.73 m²) renal impairment. There were no reported cases of NSF. Updated literature review including our results identified 340 patients with severe renal impairment or on dialysis with zero cases of NSF (0/340; 95% confidence intervals 0% and 0.9%).

CONCLUSION

No cases of NSF were documented in this study related to gadoxetic acid use in oncology patients, including those with moderate and severe renal impairment. Recent data indicate use of gadoxetic acid in patients with renal impairment can be considered low-risk.

Gadoxetate Disodium-Enhanced Imaging of Gradenigo Syndrome in End-Stage Renal Disease

ABSTRACT

A 65-year-old man with end-stage renal disease on peritoneal dialysis was admitted for new onset binocular double vision, failure to thrive, and debilitating right-sided headaches. Medical history was significant for tympanomastoidectomy for polymicrobial mastoiditis and treatment with IV antibiotics. MRI brain without contrast was read by radiology initially as showing expected postsurgical changes; however, given patient's history of mastoiditis infection, there was a high clinical suspicion for Gradenigo syndrome. MRI brain was repeated with gadoxetate contrast to minimize the risk of nephrogenic systemic fibrosis (NSF) in a patient with severe renal disease and this revealed an intracranial empyema involving both the trigeminal and abducens nerves confirming the diagnosis of Gradenigo syndrome. This case presented a diagnostic challenge because of suboptimal visualization on initial nonenhanced MRI. Gadoxetate was chosen because of its unique properties including high hepatobiliary excretion making it a safer form of gadolinium-based contrast agent that may not have the potential to precipitate NSF.

Risk of nephrogenic systemic fibrosis in patients with impaired renal function undergoing fixed-dose gadoxetic acid-enhanced magnetic resonance imaging

PURPOSE

To assess the risk of nephrogenic systemic fibrosis (NSF) in patients with renal impairment undergoing gadoxetic acid-enhanced magnetic resonance imaging.

METHODS

This retrospective study included patients who had an estimated glomerular filtration rate (eGFR) below 60 mL/min per 1.73 m² or had undergone dialysis around the time of gadoxetic acid exposure from January 2010 to November 2019. All patients received at least one intravenous injection of gadoxetic acid at a fixed dose of 2.5 mmol. The primary endpoint was the development of NSF after exposure to gadoxetic acid based on Girardi's clinicopathological scoring system.

RESULTS

A total of 204 patients with renal impairment received 424 injections of gadoxetic acid, of which 131 and 54 had an eGFR of 30-59 and < 30 mL/min per 1.73 m², respectively, and 19 had undergone hemodialysis. Eighty-two patients received multiple injections, with 23 receiving five or more injections. The dose of each exposure ranged from 0.02 to 0.07 mmol/kg and the cumulative doses ranged from 0.02 to 0.45 mmol/kg. Thirty-three patients had concomitant Child-Pugh class B or C cirrhosis. No NSF was detected during follow-up (median 20 months; range 6 days to 111 months). The upper bound of the 95% confidence interval for NSF risk was 2.2% and 1.1% per patient and examination, respectively.

CONCLUSION

No NSF was detected in this study. However, it is premature to ascertain the risk of NSF using gadoxetic acid in patients with renal impairment and further studies are warranted.