open access

Vol 22, No 3 (2017)
Original research articles
Published online: 2017-05-01
Submitted: 2016-06-28
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CT- and MRI-based gross target volume comparison in vestibular schwannomas

Bhudevi Soubhagya Kulkarni, Harjot Bajwa, Mukka Chandrashekhar, Sunil Dutt Sharma, Rohith Singareddy, Dileep Gudipudi, Shabbir Ahmad, Alok Kumar, N.V.N. Madusudan Sresty, Alluri Krishnam Raju
DOI: 10.1016/j.rpor.2017.02.002
·
Rep Pract Oncol Radiother 2017;22(3):201-208.

open access

Vol 22, No 3 (2017)
Original research articles
Published online: 2017-05-01
Submitted: 2016-06-28

Abstract

Aim

This study represents an enumeration and comparison of gross target volumes (GTV) as delineated independently on contrast-enhanced computed tomography (CT) and T1 and T2 weighted magnetic resonance imaging (MRI) in vestibular schwannomas (VS).

Background

Multiple imaging in radiotherapy improves target localization.

Methods and materials

42 patients of VS were considered for this prospective study with one patient showing bilateral tumor. The GTV was delineated separately on CT and MRI. Difference in volumes were estimated individually for all the 43 lesions and similarity was studied between CT and T1 and T2 weighted MRI.

Results

The male to female ratio for VS was found to be 1:1.3. The tumor was right sided in 34.9% and left sided in 65.1%. Tumor volumes (TV) on CT image sets were ranging from 0.251[[ce:hsp sp="0.25"/]]cc to 27.27[[ce:hsp sp="0.25"/]]cc. The TV for CT, MRI T1 and T2 weighted were 5.15[[ce:hsp sp="0.25"/]]±[[ce:hsp sp="0.25"/]]5.2[[ce:hsp sp="0.25"/]]cc, 5.8[[ce:hsp sp="0.25"/]]±[[ce:hsp sp="0.25"/]]6.23[[ce:hsp sp="0.25"/]]cc, and 5.9[[ce:hsp sp="0.25"/]]±[[ce:hsp sp="0.25"/]]6.13[[ce:hsp sp="0.25"/]]cc, respectively. Compared to MRI, CT underestimated the volumes. The mean dice coefficient between CT versus T1 and CT versus T2 was estimated to be 68.85[[ce:hsp sp="0.25"/]]±[[ce:hsp sp="0.25"/]]18.3 and 66.68[[ce:hsp sp="0.25"/]]±[[ce:hsp sp="0.25"/]]20.3, respectively. The percentage of volume difference between CT and MRI (%VD: mean[[ce:hsp sp="0.25"/]]±[[ce:hsp sp="0.25"/]]SD for T1; 28.84[[ce:hsp sp="0.25"/]]±[[ce:hsp sp="0.25"/]]15.0, T2; 35.74[[ce:hsp sp="0.25"/]]±[[ce:hsp sp="0.25"/]]16.3) and volume error (%VE: T1; 18.77[[ce:hsp sp="0.25"/]]±[[ce:hsp sp="0.25"/]]10.1, T2; 23.17[[ce:hsp sp="0.25"/]]±[[ce:hsp sp="0.25"/]]13.93) were found to be significant, taking the CT volumes as the baseline.

Conclusions

MRI with multiple sequences should be incorporated for tumor volume delineation and they provide a clear boundary between the tumor and normal tissue with critical structures nearby.

Abstract

Aim

This study represents an enumeration and comparison of gross target volumes (GTV) as delineated independently on contrast-enhanced computed tomography (CT) and T1 and T2 weighted magnetic resonance imaging (MRI) in vestibular schwannomas (VS).

Background

Multiple imaging in radiotherapy improves target localization.

Methods and materials

42 patients of VS were considered for this prospective study with one patient showing bilateral tumor. The GTV was delineated separately on CT and MRI. Difference in volumes were estimated individually for all the 43 lesions and similarity was studied between CT and T1 and T2 weighted MRI.

Results

The male to female ratio for VS was found to be 1:1.3. The tumor was right sided in 34.9% and left sided in 65.1%. Tumor volumes (TV) on CT image sets were ranging from 0.251[[ce:hsp sp="0.25"/]]cc to 27.27[[ce:hsp sp="0.25"/]]cc. The TV for CT, MRI T1 and T2 weighted were 5.15[[ce:hsp sp="0.25"/]]±[[ce:hsp sp="0.25"/]]5.2[[ce:hsp sp="0.25"/]]cc, 5.8[[ce:hsp sp="0.25"/]]±[[ce:hsp sp="0.25"/]]6.23[[ce:hsp sp="0.25"/]]cc, and 5.9[[ce:hsp sp="0.25"/]]±[[ce:hsp sp="0.25"/]]6.13[[ce:hsp sp="0.25"/]]cc, respectively. Compared to MRI, CT underestimated the volumes. The mean dice coefficient between CT versus T1 and CT versus T2 was estimated to be 68.85[[ce:hsp sp="0.25"/]]±[[ce:hsp sp="0.25"/]]18.3 and 66.68[[ce:hsp sp="0.25"/]]±[[ce:hsp sp="0.25"/]]20.3, respectively. The percentage of volume difference between CT and MRI (%VD: mean[[ce:hsp sp="0.25"/]]±[[ce:hsp sp="0.25"/]]SD for T1; 28.84[[ce:hsp sp="0.25"/]]±[[ce:hsp sp="0.25"/]]15.0, T2; 35.74[[ce:hsp sp="0.25"/]]±[[ce:hsp sp="0.25"/]]16.3) and volume error (%VE: T1; 18.77[[ce:hsp sp="0.25"/]]±[[ce:hsp sp="0.25"/]]10.1, T2; 23.17[[ce:hsp sp="0.25"/]]±[[ce:hsp sp="0.25"/]]13.93) were found to be significant, taking the CT volumes as the baseline.

Conclusions

MRI with multiple sequences should be incorporated for tumor volume delineation and they provide a clear boundary between the tumor and normal tissue with critical structures nearby.

Get Citation

Keywords

Vestibular schwannomas (VS); Computed tomography (CT); T1 weighted and T2 weighted; Magnetic resonance imaging (MRI)

About this article
Title

CT- and MRI-based gross target volume comparison in vestibular schwannomas

Journal

Reports of Practical Oncology and Radiotherapy

Issue

Vol 22, No 3 (2017)

Pages

201-208

Published online

2017-05-01

DOI

10.1016/j.rpor.2017.02.002

Bibliographic record

Rep Pract Oncol Radiother 2017;22(3):201-208.

Keywords

Vestibular schwannomas (VS)
Computed tomography (CT)
T1 weighted and T2 weighted
Magnetic resonance imaging (MRI)

Authors

Bhudevi Soubhagya Kulkarni
Harjot Bajwa
Mukka Chandrashekhar
Sunil Dutt Sharma
Rohith Singareddy
Dileep Gudipudi
Shabbir Ahmad
Alok Kumar
N.V.N. Madusudan Sresty
Alluri Krishnam Raju

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