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Image Fusion for Radiosurgery, Neurosurgery and Hypofractionated Radiotherapy.

Inoue HK, Nakajima A, Sato H, Noda SE, Saitoh J, Suzuki Y - Cureus (2015)

Bottom Line: All images are fused and registered on thin sliced CT sections and exactly demarcated targets are planned for treatment.Follow-up images are also able to register on this CT.Exact target changes, including volume, are possible in this fusion system.

View Article: PubMed Central - HTML - PubMed

Affiliation: Dept of Neurosurgery and Radiation Oncology, Institute of Neural Organization and Cyber Center, Kanto Neurosurgical Hospital.

ABSTRACT
Precise target detection is essential for radiosurgery, neurosurgery and hypofractionated radiotherapy because treatment results and complication rates are related to accuracy of the target definition. In skull base tumors and tumors around the optic pathways, exact anatomical evaluation of cranial nerves are important to avoid adverse effects on these structures close to lesions. Three-dimensional analyses of structures obtained with MR heavy T2-images and image fusion with CT thin-sliced sections are desirable to evaluate fine structures during radiosurgery and microsurgery. In vascular lesions, angiography is most important for evaluations of whole structures from feeder to drainer, shunt, blood flow and risk factors of bleeding. However, exact sites and surrounding structures in the brain are not shown on angiography. True image fusions of angiography, MR images and CT on axial planes are ideal for precise target definition. In malignant tumors, especially recurrent head and neck tumors, biologically active areas of recurrent tumors are main targets of radiosurgery. PET scan is useful for quantitative evaluation of recurrences. However, the examination is not always available at the time of radiosurgery. Image fusion of MR diffusion images with CT is always available during radiosurgery and useful for the detection of recurrent lesions. All images are fused and registered on thin sliced CT sections and exactly demarcated targets are planned for treatment. Follow-up images are also able to register on this CT. Exact target changes, including volume, are possible in this fusion system. The purpose of this review is to describe the usefulness of image fusion for 1) skull base, 2) vascular, 3) recurrent target detection, and 4) follow-up analyses in radiosurgery, neurosurgery and hypofractionated radiotherapy.

No MeSH data available.


Related in: MedlinePlus

MR to CT image fusion registration.Image fusion of point-based registration (A) and intensity-based registration (B). MR heavy T2-images fused to thin-sliced CT axial sections using point-based and Gd-enhanced MR images using intensity-based registration. Before (left) and after image fusion (right).
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FIG3: MR to CT image fusion registration.Image fusion of point-based registration (A) and intensity-based registration (B). MR heavy T2-images fused to thin-sliced CT axial sections using point-based and Gd-enhanced MR images using intensity-based registration. Before (left) and after image fusion (right).

Mentions: Image fusion to CT 0.6-1 mm slices is performed using all transported MR images (Gd-enhanced T1-images, proton density, heavy T2-images, etc.) and angiographic images on the MultiPlan system (Accuray, Inc., Sunnyvale, CA, USA). The methods used for image fusion are 1) point-based registration, 2) intensity-based registration, and 3) manual registration (correction). Point-based registration involves determining the 3-D coordinates of corresponding points in the two images and computing the transformation that best aligns these points. Intensity-based registration involves calculating a transformation between two images using a measure of alignment based only on the values of the pixels or voxels in the images [9]. In practice, three to four anatomical points, such as the union or bifurcation of arteries identical on each CT and MR image, are used in the point-based registration (Figure 3A). Data regarding the body surface are used in intensity-based registration (Figure 3B). Manual correction is used after automatic fusion to adjust target points on all images to these on CT slices.


Image Fusion for Radiosurgery, Neurosurgery and Hypofractionated Radiotherapy.

Inoue HK, Nakajima A, Sato H, Noda SE, Saitoh J, Suzuki Y - Cureus (2015)

MR to CT image fusion registration.Image fusion of point-based registration (A) and intensity-based registration (B). MR heavy T2-images fused to thin-sliced CT axial sections using point-based and Gd-enhanced MR images using intensity-based registration. Before (left) and after image fusion (right).
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4494462&req=5

FIG3: MR to CT image fusion registration.Image fusion of point-based registration (A) and intensity-based registration (B). MR heavy T2-images fused to thin-sliced CT axial sections using point-based and Gd-enhanced MR images using intensity-based registration. Before (left) and after image fusion (right).
Mentions: Image fusion to CT 0.6-1 mm slices is performed using all transported MR images (Gd-enhanced T1-images, proton density, heavy T2-images, etc.) and angiographic images on the MultiPlan system (Accuray, Inc., Sunnyvale, CA, USA). The methods used for image fusion are 1) point-based registration, 2) intensity-based registration, and 3) manual registration (correction). Point-based registration involves determining the 3-D coordinates of corresponding points in the two images and computing the transformation that best aligns these points. Intensity-based registration involves calculating a transformation between two images using a measure of alignment based only on the values of the pixels or voxels in the images [9]. In practice, three to four anatomical points, such as the union or bifurcation of arteries identical on each CT and MR image, are used in the point-based registration (Figure 3A). Data regarding the body surface are used in intensity-based registration (Figure 3B). Manual correction is used after automatic fusion to adjust target points on all images to these on CT slices.

Bottom Line: All images are fused and registered on thin sliced CT sections and exactly demarcated targets are planned for treatment.Follow-up images are also able to register on this CT.Exact target changes, including volume, are possible in this fusion system.

View Article: PubMed Central - HTML - PubMed

Affiliation: Dept of Neurosurgery and Radiation Oncology, Institute of Neural Organization and Cyber Center, Kanto Neurosurgical Hospital.

ABSTRACT
Precise target detection is essential for radiosurgery, neurosurgery and hypofractionated radiotherapy because treatment results and complication rates are related to accuracy of the target definition. In skull base tumors and tumors around the optic pathways, exact anatomical evaluation of cranial nerves are important to avoid adverse effects on these structures close to lesions. Three-dimensional analyses of structures obtained with MR heavy T2-images and image fusion with CT thin-sliced sections are desirable to evaluate fine structures during radiosurgery and microsurgery. In vascular lesions, angiography is most important for evaluations of whole structures from feeder to drainer, shunt, blood flow and risk factors of bleeding. However, exact sites and surrounding structures in the brain are not shown on angiography. True image fusions of angiography, MR images and CT on axial planes are ideal for precise target definition. In malignant tumors, especially recurrent head and neck tumors, biologically active areas of recurrent tumors are main targets of radiosurgery. PET scan is useful for quantitative evaluation of recurrences. However, the examination is not always available at the time of radiosurgery. Image fusion of MR diffusion images with CT is always available during radiosurgery and useful for the detection of recurrent lesions. All images are fused and registered on thin sliced CT sections and exactly demarcated targets are planned for treatment. Follow-up images are also able to register on this CT. Exact target changes, including volume, are possible in this fusion system. The purpose of this review is to describe the usefulness of image fusion for 1) skull base, 2) vascular, 3) recurrent target detection, and 4) follow-up analyses in radiosurgery, neurosurgery and hypofractionated radiotherapy.

No MeSH data available.


Related in: MedlinePlus