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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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Original T2-w MRI images for (a) 24-hour, (b) 1-month, (c) 3-month, and (d) 6 month post-LITT.(e) , (f) , and (g) , corresponding to difference maps for T2-w MRI computed across subsequent time-points , , , and . Fig. 7(h) shows temporal profiles of every MR protocol ,  reflecting the changes in MR markers at subsequent time-points.
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pone-0114293-g007: Original T2-w MRI images for (a) 24-hour, (b) 1-month, (c) 3-month, and (d) 6 month post-LITT.(e) , (f) , and (g) , corresponding to difference maps for T2-w MRI computed across subsequent time-points , , , and . Fig. 7(h) shows temporal profiles of every MR protocol , reflecting the changes in MR markers at subsequent time-points.

Mentions: Fig. 7 shows difference maps obtained across multiple time-points for the T2-w MRI protocol for an epilepsy study. Figs. 7 (a)–(d) show the original T2-w MRI slices containing the ablation zone for 24-hours, 1-month, 3-months, and 6-months respectively, while the corresponding difference maps, , , and are shown in Figs. 7 (e), (f), and (g) respectively. Temporal profiles for every protocol, T1w, T2w, GRE, FLAIR, and ADC are shown in different colors in Fig. 7(h), obtained by plotting the mean intensity value at every time-point. Note how the changes are more prominent between as compared to , and . This appears to suggest that most of the early LITT effects such as edema, and swelling for epilepsy treatment occur and subside within the first one month.


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

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

Original T2-w MRI images for (a) 24-hour, (b) 1-month, (c) 3-month, and (d) 6 month post-LITT.(e) , (f) , and (g) , corresponding to difference maps for T2-w MRI computed across subsequent time-points , , , and . Fig. 7(h) shows temporal profiles of every MR protocol ,  reflecting the changes in MR markers at subsequent time-points.
© Copyright Policy
Related In: Results  -  Collection

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

pone-0114293-g007: Original T2-w MRI images for (a) 24-hour, (b) 1-month, (c) 3-month, and (d) 6 month post-LITT.(e) , (f) , and (g) , corresponding to difference maps for T2-w MRI computed across subsequent time-points , , , and . Fig. 7(h) shows temporal profiles of every MR protocol , reflecting the changes in MR markers at subsequent time-points.
Mentions: Fig. 7 shows difference maps obtained across multiple time-points for the T2-w MRI protocol for an epilepsy study. Figs. 7 (a)–(d) show the original T2-w MRI slices containing the ablation zone for 24-hours, 1-month, 3-months, and 6-months respectively, while the corresponding difference maps, , , and are shown in Figs. 7 (e), (f), and (g) respectively. Temporal profiles for every protocol, T1w, T2w, GRE, FLAIR, and ADC are shown in different colors in Fig. 7(h), obtained by plotting the mean intensity value at every time-point. Note how the changes are more prominent between as compared to , and . This appears to suggest that most of the early LITT effects such as edema, and swelling for epilepsy treatment occur and subside within the first one month.

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