Limits...
Quantifying Post- Laser Ablation Prostate Therapy Changes on MRI via a Domain-Specific Biomechanical Model: Preliminary Findings.

Toth R, Sperling D, Madabhushi A - PLoS ONE (2016)

Bottom Line: It combines the aggressive benefits of radiation treatment (destroying cancer cells) without the harmful side effects (due to its precise localization).Our results suggest that our new methodology is able to capture and quantify the degree of laser-induced changes to the prostate.The quantitative measurements reflecting of the deformation changes can be used to track treatment response over time.

View Article: PubMed Central - PubMed

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

ABSTRACT
Focal laser ablation destroys cancerous cells via thermal destruction of tissue by a laser. Heat is absorbed, causing thermal necrosis of the target region. It combines the aggressive benefits of radiation treatment (destroying cancer cells) without the harmful side effects (due to its precise localization). MRI is typically used pre-treatment to determine the targeted area, and post-treatment to determine efficacy by detecting necrotic tissue, or tumor recurrence. However, no system exists to quantitatively evaluate the post-treatment effects on the morphology and structure via MRI. To quantify these changes, the pre- and post-treatment MR images must first be spatially aligned. The goal is to quantify (a) laser-induced shape-based changes, and (b) changes in MRI parameters post-treatment. The shape-based changes may be correlated with treatment efficacy, and the quantitative effects of laser treatment over time is currently poorly understood. This work attempts to model changes in gland morphology following laser treatment due to (1) patient alignment, (2) changes due to surrounding organs such as the bladder and rectum, and (3) changes due to the treatment itself. To isolate the treatment-induced shape-based changes, the changes from (1) and (2) are first modeled and removed using a finite element model (FEM). A FEM models the physical properties of tissue. The use of a physical biomechanical model is important since a stated goal of this work is to determine the physical shape-based changes to the prostate from the treatment, and therefore only physical real deformations are to be allowed. A second FEM is then used to isolate the physical, shape-based, treatment-induced changes. We applied and evaluated our model in capturing the laser induced changes to the prostate morphology on eight patients with 3.0 Tesla, T2-weighted MRI, acquired approximately six months following treatment. Our results suggest the laser treatment causes a decrease in prostate volume, which appears to manifest predominantly at the site of ablation. After spatially aligning the images, changes to MRI intensity values are clearly visible at the site of ablation. Our results suggest that our new methodology is able to capture and quantify the degree of laser-induced changes to the prostate. The quantitative measurements reflecting of the deformation changes can be used to track treatment response over time.

Show MeSH

Related in: MedlinePlus

Illustration of the focal laser ablation needle locations on T2-w MRI during the procedure for two different patients ((a), (c)).After registration, the difference between the MRI intensity values (as a relative percent change) are shown as colored values in ((b)) and 3D ((d)), where cool blue colors represent regions corresponding to small differences (0%), while hot red colors represent regions of large differences (11%) in MRI intensity values. Most of the hot colors are correlated with the needle locations (shown as orange arrows).
© Copyright Policy
Related In: Results  -  Collection

License
getmorefigures.php?uid=PMC4835053&req=5

pone.0150016.g006: Illustration of the focal laser ablation needle locations on T2-w MRI during the procedure for two different patients ((a), (c)).After registration, the difference between the MRI intensity values (as a relative percent change) are shown as colored values in ((b)) and 3D ((d)), where cool blue colors represent regions corresponding to small differences (0%), while hot red colors represent regions of large differences (11%) in MRI intensity values. Most of the hot colors are correlated with the needle locations (shown as orange arrows).

Mentions: Fig 6(a) and 6(b) show MRI scans both during and after the laser treatment, respectively. The laser needle during the procedure at the site of ablation is clearly visible in Fig 6(a). The changes in MRI intensity values following the FEM based registration are shown as a colored heatmap in Fig 6(d). Hot colors represent areas of large changes in MRI intensity values and cooler colors represent areas of small changes. The same representations are shown for a second patient in Fig 6(c) and 6(d). This particular patient had two sites of ablation, both shown by the MRI images during treatment in Fig 6(c).


Quantifying Post- Laser Ablation Prostate Therapy Changes on MRI via a Domain-Specific Biomechanical Model: Preliminary Findings.

Toth R, Sperling D, Madabhushi A - PLoS ONE (2016)

Illustration of the focal laser ablation needle locations on T2-w MRI during the procedure for two different patients ((a), (c)).After registration, the difference between the MRI intensity values (as a relative percent change) are shown as colored values in ((b)) and 3D ((d)), where cool blue colors represent regions corresponding to small differences (0%), while hot red colors represent regions of large differences (11%) in MRI intensity values. Most of the hot colors are correlated with the needle locations (shown as orange arrows).
© Copyright Policy
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4835053&req=5

pone.0150016.g006: Illustration of the focal laser ablation needle locations on T2-w MRI during the procedure for two different patients ((a), (c)).After registration, the difference between the MRI intensity values (as a relative percent change) are shown as colored values in ((b)) and 3D ((d)), where cool blue colors represent regions corresponding to small differences (0%), while hot red colors represent regions of large differences (11%) in MRI intensity values. Most of the hot colors are correlated with the needle locations (shown as orange arrows).
Mentions: Fig 6(a) and 6(b) show MRI scans both during and after the laser treatment, respectively. The laser needle during the procedure at the site of ablation is clearly visible in Fig 6(a). The changes in MRI intensity values following the FEM based registration are shown as a colored heatmap in Fig 6(d). Hot colors represent areas of large changes in MRI intensity values and cooler colors represent areas of small changes. The same representations are shown for a second patient in Fig 6(c) and 6(d). This particular patient had two sites of ablation, both shown by the MRI images during treatment in Fig 6(c).

Bottom Line: It combines the aggressive benefits of radiation treatment (destroying cancer cells) without the harmful side effects (due to its precise localization).Our results suggest that our new methodology is able to capture and quantify the degree of laser-induced changes to the prostate.The quantitative measurements reflecting of the deformation changes can be used to track treatment response over time.

View Article: PubMed Central - PubMed

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

ABSTRACT
Focal laser ablation destroys cancerous cells via thermal destruction of tissue by a laser. Heat is absorbed, causing thermal necrosis of the target region. It combines the aggressive benefits of radiation treatment (destroying cancer cells) without the harmful side effects (due to its precise localization). MRI is typically used pre-treatment to determine the targeted area, and post-treatment to determine efficacy by detecting necrotic tissue, or tumor recurrence. However, no system exists to quantitatively evaluate the post-treatment effects on the morphology and structure via MRI. To quantify these changes, the pre- and post-treatment MR images must first be spatially aligned. The goal is to quantify (a) laser-induced shape-based changes, and (b) changes in MRI parameters post-treatment. The shape-based changes may be correlated with treatment efficacy, and the quantitative effects of laser treatment over time is currently poorly understood. This work attempts to model changes in gland morphology following laser treatment due to (1) patient alignment, (2) changes due to surrounding organs such as the bladder and rectum, and (3) changes due to the treatment itself. To isolate the treatment-induced shape-based changes, the changes from (1) and (2) are first modeled and removed using a finite element model (FEM). A FEM models the physical properties of tissue. The use of a physical biomechanical model is important since a stated goal of this work is to determine the physical shape-based changes to the prostate from the treatment, and therefore only physical real deformations are to be allowed. A second FEM is then used to isolate the physical, shape-based, treatment-induced changes. We applied and evaluated our model in capturing the laser induced changes to the prostate morphology on eight patients with 3.0 Tesla, T2-weighted MRI, acquired approximately six months following treatment. Our results suggest the laser treatment causes a decrease in prostate volume, which appears to manifest predominantly at the site of ablation. After spatially aligning the images, changes to MRI intensity values are clearly visible at the site of ablation. Our results suggest that our new methodology is able to capture and quantify the degree of laser-induced changes to the prostate. The quantitative measurements reflecting of the deformation changes can be used to track treatment response over time.

Show MeSH
Related in: MedlinePlus