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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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Contributions of each of the MR protocols (normalized between 0 and 1) in (a) capturing treatment changes post-LITT at 24-hour, 1-month, 3-month, and 6-month time periods for epilepsy, and (b) differentiating successful treatment and tumor recurrence at 24- hour, 2-month, 4-month, 6-month, 9-month, and 11-month post-LITT for GBM studies.Fig. 9(a) illustrates that T1w MRI and T2-GRE were most discriminative in distinguishing patients with successful treatment and tumor recurrence across all time-points, as compared to T2w MRI, and FLAIR. Similarly, Fig. 9(b) suggest that ADC was identified as being most reflective of early treatment changes (up to 3-months), while T1w was found to be more reflective of early delayed treatment changes (1-month, 3-months) compared to the other protocols under evaluation.
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pone-0114293-g009: Contributions of each of the MR protocols (normalized between 0 and 1) in (a) capturing treatment changes post-LITT at 24-hour, 1-month, 3-month, and 6-month time periods for epilepsy, and (b) differentiating successful treatment and tumor recurrence at 24- hour, 2-month, 4-month, 6-month, 9-month, and 11-month post-LITT for GBM studies.Fig. 9(a) illustrates that T1w MRI and T2-GRE were most discriminative in distinguishing patients with successful treatment and tumor recurrence across all time-points, as compared to T2w MRI, and FLAIR. Similarly, Fig. 9(b) suggest that ADC was identified as being most reflective of early treatment changes (up to 3-months), while T1w was found to be more reflective of early delayed treatment changes (1-month, 3-months) compared to the other protocols under evaluation.

Mentions: Fig. 9(a) illustrates the contributions of each of the protocols, based on the voting scheme, described in the Methods Section for the epilepsy cohort. The weights of the individual MRI markers were normalized between 0 and 1 over the two studies for different time points. The top 25 profiles with highest mean intensity differences for and lowest mean intensity differences for , , were identified (based on the trends observed in Fig. 5(j)), and the protocols that most commonly occurred over the top 25 weight profiles were identified as candidate MR markers.


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

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

Contributions of each of the MR protocols (normalized between 0 and 1) in (a) capturing treatment changes post-LITT at 24-hour, 1-month, 3-month, and 6-month time periods for epilepsy, and (b) differentiating successful treatment and tumor recurrence at 24- hour, 2-month, 4-month, 6-month, 9-month, and 11-month post-LITT for GBM studies.Fig. 9(a) illustrates that T1w MRI and T2-GRE were most discriminative in distinguishing patients with successful treatment and tumor recurrence across all time-points, as compared to T2w MRI, and FLAIR. Similarly, Fig. 9(b) suggest that ADC was identified as being most reflective of early treatment changes (up to 3-months), while T1w was found to be more reflective of early delayed treatment changes (1-month, 3-months) compared to the other protocols under evaluation.
© Copyright Policy
Related In: Results  -  Collection

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

pone-0114293-g009: Contributions of each of the MR protocols (normalized between 0 and 1) in (a) capturing treatment changes post-LITT at 24-hour, 1-month, 3-month, and 6-month time periods for epilepsy, and (b) differentiating successful treatment and tumor recurrence at 24- hour, 2-month, 4-month, 6-month, 9-month, and 11-month post-LITT for GBM studies.Fig. 9(a) illustrates that T1w MRI and T2-GRE were most discriminative in distinguishing patients with successful treatment and tumor recurrence across all time-points, as compared to T2w MRI, and FLAIR. Similarly, Fig. 9(b) suggest that ADC was identified as being most reflective of early treatment changes (up to 3-months), while T1w was found to be more reflective of early delayed treatment changes (1-month, 3-months) compared to the other protocols under evaluation.
Mentions: Fig. 9(a) illustrates the contributions of each of the protocols, based on the voting scheme, described in the Methods Section for the epilepsy cohort. The weights of the individual MRI markers were normalized between 0 and 1 over the two studies for different time points. The top 25 profiles with highest mean intensity differences for and lowest mean intensity differences for , , were identified (based on the trends observed in Fig. 5(j)), and the protocols that most commonly occurred over the top 25 weight profiles were identified as candidate MR markers.

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