Uday Krishna, A S (2012) Magnetic Resonance Spectroscopy (MRS) based target volume delineation of High Grade Glomas. Masters thesis, Christian Medical College, Vellore.
|
Text
200901112uday_krishna.pdf Download (2MB) | Preview |
Abstract
PURPOSE: The primary objective is to assess the changes in the radiation target volume by addition of Magnetic Resonance Spectroscopy when compared to Computerised Tomography (CT)-Magnetic Resonance Imaging (MRI) alone in treatment planning of High Grade Gliomas (HGG). The secondary objective of this study is to examine the feasibility of incorporating Magnetic Resonance Spectroscopy imaging into the routine treatment planning process. METHOD: A study was conducted to assess target volume changes of high grade gliomas by addition of MRSI to routine CT-MRI based volume delineation. Out of 22 glioma patients that were enrolled in the study, 10 patients who met the inclusion and exclusion criteria underwent preoperative and post operative imaging with MRI and MRSI. Target volumes of GTV & PTV were drawn on CT-MRI co-registered images according to the RTOG protocol and later MRSI based risk volumes were drawn on the T2 FLAIR images of MRI used for planning. Three risk volumes were identified that included High risk area defined by Choline- NAA Index (CNI) of more than 3, Intermediate risk area defined by CNI 1.5-3 plus Choline Creatine Index (CCI) >1.5. Low risk area was defined by regions of CNI<1.5. Low risk area was grown unifromly by a margin of 5 mm and this was named as PTV-MRS. Comparison was made between GTV defined by T1 MRI, T2 MRI, and GTV defined by high risk area and intermediate risk area Similarly PTV defined by MRI and MRS was compared. RESULTS AND CONCLUSIONS: 1. PTV defined by MRS was 57% less than that of PTV MRI. This could result in reduction in normal tissue irradiation leading to decreased NT toxicity and facilitate delivery of required doses to the target. 2. T2W MRI defined GTV was more by 40% on an average from MRS (intermediate risk area) defined GTV and the range from 12% -76%. It is possible that a significant amount of normal tissue being irradiated in target volume defined by MRI. 3. When T2W FLAIR is used in defining GTV, volume of GTV defined by MRI that was beyond MRS was about 61.58 cc which indicated the amount of normal brain in the irradiated volume. MRS defined GTV was about 7.32 cc beyond the T2W FLAIR volume which is the active disease not addressed by MRI alone. Though there is disjoint volumes, when a margin of 2.5 cm is given on MRI this disjoint volume gets covered in the PTV. Wilcoxon sign rank test was performed and found that there was statistical significance between GTV and PTV volumes generated by MRI and MRS. However large number of patients are needed to confirm the above findings and for implementation of MRSI into routine planning process.
| Item Type: | Thesis (Masters) |
|---|---|
| Additional Information: | Reg.No.20103753 |
| Uncontrolled Keywords: | High Grade Glioma, Magnetic resonance spectroscopy, Computerised tomography, Magnetic Resonance imaging. |
| Subjects: | MEDICAL > Paediatrics |
| Depositing User: | Subramani R |
| Date Deposited: | 14 Sep 2020 03:49 |
| Last Modified: | 14 Sep 2020 09:00 |
| URI: | http://repository-tnmgrmu.ac.in/id/eprint/13130 |
Actions (login required)
 |
View Item |
