Effects of thermal denaturation on the longitudinal relaxation time (T1) of water protons in protein solutions: Study of the factors determining the T1 of water protons

Correction for the Article “MRI-Guided Electrophysiology Intervention” by Henry R. Halperin and Aravindan Kolandaivelu

“…46 T1 changes may be related to tissue heating, protein denaturation, and changes in intracellular and extracellular free water distribution during and following ablation. [45][46][47] Similar stability of imaging characteristics were reported from 30 minutes to 12 hours following ablation, though the lesion contrast by T1-weighted imaging appears to be less than for T2-weighted im- aging. 46 Gadolinium delayed enhancement CMR (DECMR) can provide better visualization of RF ablation lesions compared with non-contrast imaging techniques ( Figure 6).…”

Characterization of acute and subacute radiofrequency ablation lesions with nonenhanced magnetic resonance imaging

“…Ablations appeared as homogenous areas of increased signal intensity, which correlated well with the pathological lesion size and did not significantly change during the follow-up duration of 12 hours. The increased signal intensity in T1-weighted images likely reflects changes in the T1-relaxation parameters due to configuration changes of the denaturized proteins in the necrotic areas [1] as well as the heat-induced formation of methemoglobin from deoxyhemoglobin. [4] However, CNR was decreased in comparison to the T2-weighted images and image quality was less consistent between individual experiments.…”

“…As the increased signal intensity is likely due to denaturized protein within the ablation lesion, this may more accurately describe the truly necrotic area of the RF lesion. [1] This difference of the imaging protocols was also reflected in the transmurality and gap measurements and resulted in either a high sensitivity or specificity, respectively. This raises the intriguing question, if specific MRI protocols might be able to differentiate different histological properties of the myocardium (such as reversible edema vs. permanent necrosis), providing a potential tool to evaluate the procedural success and enabling a future application of "MR histology".…”

“…[6] Correspondingly, we observed in the T1 protocols that those areas appeared as islets of less signal intensity. As the higher T1 signal of the RF lesion is likely due to the denaturized proteins in the ablated area, [1] fluid filled cavities would be expected to display little or less T1 signal.…”

MRI for electrophysiology

“…They also characterized noncontrast T1-weighted imaging of ablation lesions. Altered ablation lesion T1 may be related to tissue heating, protein denaturation, and changes in intracellular and extracellular water distribution during and following ablation [39][40][41]. Stability of lesion characteristics was noted from 30 minutes to 12 hours after ablation for both T2-and T1-weighted imaging techniques, permitting comparison of multiple ablation lesions placed at different times over the course of a procedure.…”