Splenic T1-mapping: a novel quantitative method for assessing adenosine stress adequacy for cardiovascular magnetic resonance.

Abstract

BACKGROUND:

Perfusion cardiovascular magnetic resonance (CMR) performed with inadequate adenosine stress leads to false-negative results and suboptimal clinical management. The recently proposed marker of adequate stress, the "splenic switch-off" sign, detects splenic blood flow attenuation during stress perfusion (spleen appears dark), but can only be assessed after gadolinium first-pass, when it is too late to optimize the stress response. Reduction in splenic blood volume during adenosine stress is expected to shorten native splenic T1, which may predict splenic switch-off without the need for gadolinium.

METHODS:

Two-hundred and twelve subjects underwent adenosine stress CMR: 1.5 T (n = 104; 75 patients, 29 healthy controls); 3 T (n = 108; 86 patients, 22 healthy controls). Native T1spleen was assessed using heart-rate-independent ShMOLLI prototype sequence at rest and during adenosine stress (140 μg/kg/min, 4 min, IV) in 3 short-axis slices (basal, mid-ventricular, apical). This was compared with changes in peak splenic perfusion signal intensity (ΔSIspleen) and the "splenic switch-off" sign on conventional stress/rest gadolinium perfusion imaging. T1spleen values were obtained blinded to perfusion ΔSIspleen, both were derived using regions of interest carefully placed to avoid artefacts and partial-volume effects.

RESULTS:

Normal resting splenic T1 values were 1102 ± 66 ms (1.5 T) and 1352 ± 114 ms (3 T), slightly higher than in patients (1083 ± 59 ms, p = 0.04; 1295 ± 105 ms, p = 0.01, respectively). T1spleen decreased significantly during adenosine stress (mean ΔT1spleen ~ -40 ms), independent of field strength, age, gender, and cardiovascular diseases. While ΔT1spleen correlated strongly with ΔSIspleen (rho = 0.70, p < 0.0001); neither indices showed significant correlations with conventional hemodynamic markers (rate pressure product) during stress. By ROC analysis, a ΔT1spleen threshold of ≥ -30 ms during stress predicted the "splenic switch-off" sign (AUC 0.90, p < 0.0001) with sensitivity (90%), specificity (88%), accuracy (90%), PPV (98%), NPV (42%).

CONCLUSIONS:

Adenosine stress and rest splenic T1-mapping is a novel method for assessing stress responses, independent of conventional hemodynamic parameters. It enables prediction of the visual "splenic switch-off" sign without the need for gadolinium, and correlates well to changes in splenic signal intensity during stress/rest perfusion imaging. ΔT1spleen holds promise to facilitate optimization of stress responses before gadolinium first-pass perfusion CMR.

• Authors: Alexander Liu, Rohan S Wijesurendra, Rina Ariga, Masliza Mahmod, Eylem Levelt, Andreas Greiser, Mario Petrou, George Krasopoulos, John C Forfar, Rajesh K Kharbanda, Keith M Channon, Stefan Neubauer, Stefan K Piechnik, Vanessa M Ferreira
• Journal: Journal of cardiovascular magnetic resonance : official journal of the Society for Cardiovascular Magnetic Resonance (J Cardiovasc Magn Reson) Vol. 19 Issue 1 Pg. 1 (Jan 13 2017) ISSN: 1532-429X [Electronic] England
• PMID: 28081721 (Publication Type: Journal Article)

Chemical References

• Contrast Media
• Vasodilator Agents
• Gadolinium
• Adenosine

Topics

• Adenosine (administration & dosage)
• Adult
• Aged
• Area Under Curve
• Case-Control Studies
• Contrast Media (administration & dosage)
• Coronary Circulation
• False Negative Reactions
• Female
• Gadolinium (administration & dosage)
• Heart Diseases (diagnostic imaging, physiopathology)
• Heart Rate
• Hemodynamics
• Humans
• Magnetic Resonance Imaging
• Male
• Middle Aged
• Myocardial Perfusion Imaging (methods)
• Predictive Value of Tests
• ROC Curve
• Reproducibility of Results
• Splanchnic Circulation
• Spleen (blood supply, diagnostic imaging)
• Vasodilator Agents (administration & dosage)