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Identifying MRI markers associated with early response following laser ablation for neurological disorders: preliminary findings.

Tiwari P, Danish S, Madabhushi A - PLoS ONE (2014)

Bottom Line: Although highly promising, the long-term effects of laser ablation as a viable treatment option for neurological disorders have yet to be rigorously studied and quantified.In this work, we present a quantitative framework for monitoring per-voxel thermal-induced changes post-LITT over time on multi parametric MRI.On a cohort of six GBM studies we found that (a) it may be important for the initial treatment-related changes to subside to more reliably capture MRI markers relating to tumor recurrence, and (b) T1w MRI and T2-GRE may better differentiate changes that may correspond to tumor recurrence from patients with no recurrence, as compared to T2w-MRI, and FLAIR.

View Article: PubMed Central - PubMed

Affiliation: Department of Biomedical Engineering, Case Western Reserve University, Cleveland, Ohio, United States of America.

ABSTRACT
There is a renewed interest in MR-guided laser interstitial thermal therapy (LITT) as a minimally invasive alternative to craniotomy for local treatment of various brain tumors and epilepsy. LITT allows for focused delivery of laser energy monitored in real time by MRI, for precise ablation of the lesion. Although highly promising, the long-term effects of laser ablation as a viable treatment option for neurological disorders have yet to be rigorously studied and quantified. In this work, we present a quantitative framework for monitoring per-voxel thermal-induced changes post-LITT over time on multi parametric MRI. We demonstrate that voxel-by-voxel quantification of MRI markers over time can enable a careful and accurate (a) characterization of early LITT-related changes (if and when they are exaggerated and when they subside), and (b) identification and monitoring of MRI markers that potentially allow for better quantification of response to LITT therapy. The framework was evaluated on two distinct cohorts of patients (GBM, epilepsy), who were monitored post-LITT at regular time-intervals via multi-parametric MRI. On a cohort of six GBM studies we found that (a) it may be important for the initial treatment-related changes to subside to more reliably capture MRI markers relating to tumor recurrence, and (b) T1w MRI and T2-GRE may better differentiate changes that may correspond to tumor recurrence from patients with no recurrence, as compared to T2w-MRI, and FLAIR. Similarly, our preliminary analysis of four epilepsy studies suggests that (a) early LITT changes (attributed to swelling, edema) appear to subside within 4-weeks post-LITT, and (b) ADC may be more reflective of early treatment changes (up to 1 month), while T1w may be more reflective of early delayed treatment changes (1 month, 3 months), while T2-w and T2-FLAIR appeared to be more sensitive to late treatment related changes (6-months post-LITT) compared to the other MRI protocols under evaluation.

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Flowchart showing different modules for each of the three objectives, where (a) illustrates the methods for objective 1 to obtain a temporal MRI profile of differences plotted with respect to baseline, while (b) illustrates the methods for objective 2 involving studying when early treatment changes subside by plotting differences in MRI markers at subsequent time-points.Fig. 2(c) illustrates the methods for objective 3 involving developing a fused multi parametric MRI signature by computing a weighted combination of MRI protocols at different time-points.
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pone-0114293-g002: Flowchart showing different modules for each of the three objectives, where (a) illustrates the methods for objective 1 to obtain a temporal MRI profile of differences plotted with respect to baseline, while (b) illustrates the methods for objective 2 involving studying when early treatment changes subside by plotting differences in MRI markers at subsequent time-points.Fig. 2(c) illustrates the methods for objective 3 involving developing a fused multi parametric MRI signature by computing a weighted combination of MRI protocols at different time-points.

Mentions: In this work, we address these challenges by developing a quantitative framework (Fig. 2) that encapsulates the appropriate intensity standardization, image co-registration, and quantification modules to accurately capture localized per-voxel treatment changes between pre-, and post-LITT, and weight them to create a multi-parametric MRI map that potentially can better capture treatment related changes than any of the individual MRI protocols. Below we summarize each of the different modules of the presented quantitative framework.


Identifying MRI markers associated with early response following laser ablation for neurological disorders: preliminary findings.

Tiwari P, Danish S, Madabhushi A - PLoS ONE (2014)

Flowchart showing different modules for each of the three objectives, where (a) illustrates the methods for objective 1 to obtain a temporal MRI profile of differences plotted with respect to baseline, while (b) illustrates the methods for objective 2 involving studying when early treatment changes subside by plotting differences in MRI markers at subsequent time-points.Fig. 2(c) illustrates the methods for objective 3 involving developing a fused multi parametric MRI signature by computing a weighted combination of MRI protocols at different time-points.
© Copyright Policy
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4263602&req=5

pone-0114293-g002: Flowchart showing different modules for each of the three objectives, where (a) illustrates the methods for objective 1 to obtain a temporal MRI profile of differences plotted with respect to baseline, while (b) illustrates the methods for objective 2 involving studying when early treatment changes subside by plotting differences in MRI markers at subsequent time-points.Fig. 2(c) illustrates the methods for objective 3 involving developing a fused multi parametric MRI signature by computing a weighted combination of MRI protocols at different time-points.
Mentions: In this work, we address these challenges by developing a quantitative framework (Fig. 2) that encapsulates the appropriate intensity standardization, image co-registration, and quantification modules to accurately capture localized per-voxel treatment changes between pre-, and post-LITT, and weight them to create a multi-parametric MRI map that potentially can better capture treatment related changes than any of the individual MRI protocols. Below we summarize each of the different modules of the presented quantitative framework.

Bottom Line: Although highly promising, the long-term effects of laser ablation as a viable treatment option for neurological disorders have yet to be rigorously studied and quantified.In this work, we present a quantitative framework for monitoring per-voxel thermal-induced changes post-LITT over time on multi parametric MRI.On a cohort of six GBM studies we found that (a) it may be important for the initial treatment-related changes to subside to more reliably capture MRI markers relating to tumor recurrence, and (b) T1w MRI and T2-GRE may better differentiate changes that may correspond to tumor recurrence from patients with no recurrence, as compared to T2w-MRI, and FLAIR.

View Article: PubMed Central - PubMed

Affiliation: Department of Biomedical Engineering, Case Western Reserve University, Cleveland, Ohio, United States of America.

ABSTRACT
There is a renewed interest in MR-guided laser interstitial thermal therapy (LITT) as a minimally invasive alternative to craniotomy for local treatment of various brain tumors and epilepsy. LITT allows for focused delivery of laser energy monitored in real time by MRI, for precise ablation of the lesion. Although highly promising, the long-term effects of laser ablation as a viable treatment option for neurological disorders have yet to be rigorously studied and quantified. In this work, we present a quantitative framework for monitoring per-voxel thermal-induced changes post-LITT over time on multi parametric MRI. We demonstrate that voxel-by-voxel quantification of MRI markers over time can enable a careful and accurate (a) characterization of early LITT-related changes (if and when they are exaggerated and when they subside), and (b) identification and monitoring of MRI markers that potentially allow for better quantification of response to LITT therapy. The framework was evaluated on two distinct cohorts of patients (GBM, epilepsy), who were monitored post-LITT at regular time-intervals via multi-parametric MRI. On a cohort of six GBM studies we found that (a) it may be important for the initial treatment-related changes to subside to more reliably capture MRI markers relating to tumor recurrence, and (b) T1w MRI and T2-GRE may better differentiate changes that may correspond to tumor recurrence from patients with no recurrence, as compared to T2w-MRI, and FLAIR. Similarly, our preliminary analysis of four epilepsy studies suggests that (a) early LITT changes (attributed to swelling, edema) appear to subside within 4-weeks post-LITT, and (b) ADC may be more reflective of early treatment changes (up to 1 month), while T1w may be more reflective of early delayed treatment changes (1 month, 3 months), while T2-w and T2-FLAIR appeared to be more sensitive to late treatment related changes (6-months post-LITT) compared to the other MRI protocols under evaluation.

Show MeSH
Related in: MedlinePlus