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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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Temporal profiles showing changes in MRI markers over time for (a) T1w MRI, (b) T2w MRI, (c) T2-GRE, (d) FLAIR, (e) volumetric changes on T1w MRI, and (f) fused multi-parametric MRI for a GBM patient identified as responder (shown in green), against a GBM patient identified as a non-responder (shown in red) to the LITT treatment.Note that multi-parametric MRI profile provide a better distinction across the two classes as compared to individual T1w, T2w, and T2-GRE temporal profiles, and shows similar trends as obtained via volumetric analysis post-LITT.
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pone-0114293-g008: Temporal profiles showing changes in MRI markers over time for (a) T1w MRI, (b) T2w MRI, (c) T2-GRE, (d) FLAIR, (e) volumetric changes on T1w MRI, and (f) fused multi-parametric MRI for a GBM patient identified as responder (shown in green), against a GBM patient identified as a non-responder (shown in red) to the LITT treatment.Note that multi-parametric MRI profile provide a better distinction across the two classes as compared to individual T1w, T2w, and T2-GRE temporal profiles, and shows similar trends as obtained via volumetric analysis post-LITT.

Mentions: Fig. 8 shows temporal profiles computed for T1w MRI (a), T2w MRI (b), T2-GRE (c), and T2-FLAIR (d) respectively, for a GBM patient identified to have successful treatment, no recurrence at the time of evaluation, (shown in green), against a GBM patient identified to have tumor recurrence (shown in red) to the LITT treatment. The trends of changes across the two classes suggest that, (a) MR changes for successful treatment become steady after a brief spike (due to edema and swelling) as against the patients with tumor recurrence where the trends are not consistent, and (b) 16-week (4-month post-LITT) time-point for T1w, T2w, and T2-GRE MRI, appears to show a better distinction between successful treatment (no signs of recurrence) and tumor recurrence than T2-FLAIR. For each of these protocols (T1w, T2w and GRE), changes in imaging markers for successful treatment become steady after 4-months, expect for tumor recurrence, where the difference intensities start to spike.


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

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

Temporal profiles showing changes in MRI markers over time for (a) T1w MRI, (b) T2w MRI, (c) T2-GRE, (d) FLAIR, (e) volumetric changes on T1w MRI, and (f) fused multi-parametric MRI for a GBM patient identified as responder (shown in green), against a GBM patient identified as a non-responder (shown in red) to the LITT treatment.Note that multi-parametric MRI profile provide a better distinction across the two classes as compared to individual T1w, T2w, and T2-GRE temporal profiles, and shows similar trends as obtained via volumetric analysis post-LITT.
© Copyright Policy
Related In: Results  -  Collection

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

pone-0114293-g008: Temporal profiles showing changes in MRI markers over time for (a) T1w MRI, (b) T2w MRI, (c) T2-GRE, (d) FLAIR, (e) volumetric changes on T1w MRI, and (f) fused multi-parametric MRI for a GBM patient identified as responder (shown in green), against a GBM patient identified as a non-responder (shown in red) to the LITT treatment.Note that multi-parametric MRI profile provide a better distinction across the two classes as compared to individual T1w, T2w, and T2-GRE temporal profiles, and shows similar trends as obtained via volumetric analysis post-LITT.
Mentions: Fig. 8 shows temporal profiles computed for T1w MRI (a), T2w MRI (b), T2-GRE (c), and T2-FLAIR (d) respectively, for a GBM patient identified to have successful treatment, no recurrence at the time of evaluation, (shown in green), against a GBM patient identified to have tumor recurrence (shown in red) to the LITT treatment. The trends of changes across the two classes suggest that, (a) MR changes for successful treatment become steady after a brief spike (due to edema and swelling) as against the patients with tumor recurrence where the trends are not consistent, and (b) 16-week (4-month post-LITT) time-point for T1w, T2w, and T2-GRE MRI, appears to show a better distinction between successful treatment (no signs of recurrence) and tumor recurrence than T2-FLAIR. For each of these protocols (T1w, T2w and GRE), changes in imaging markers for successful treatment become steady after 4-months, expect for tumor recurrence, where the difference intensities start to spike.

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