Comparison of Tumor Volume Between PET and MRI in Cervical Cancer With Hybrid PET/MR

2014 ◽  
Vol 24 (4) ◽  
pp. 744-750 ◽  
Author(s):  
Shaomin Zhang ◽  
Jun Xin ◽  
Qiyong Guo ◽  
Jietao Ma ◽  
Quanmei Ma ◽  
...  

ObjectiveThis study aimed to compare the tumor volume between magnetic resonance imaging–defined gross tumor volume (MR-GTV) and positron emission tomography–defined GTV (PET-GTV) in cervical cancer with hybrid PET/MR.Materials and MethodsTwenty-seven patients with cervical cancer underwent PET/MR pelvic examination before radiotherapy. The MR-GTV was manually outlined on T2-weighted MR images. The PET-GTV was autocontoured on PET images using a 40% maximum standardized uptake value threshold. Results were analyzed by Pearson analysis, Bland-Altman plot, and 1-way analysis of variance.ResultsMagnetic resonance imaging–GTV significantly correlated with PET-GTV (r2 = 0.797, P < 0.001). The Bland-Altman plot showed a bad agreement between MR-GTV and PET-GTV. The PET-GTV underestimated the MR-GTV in 23 of 27 tumors. Patients were divided into the following 3 groups according to MR-GTV: less than 14 mL (n = 6), 14 to 62 mL (n = 12), and 62 mL or more (n = 9). The mean (SD) MR-GTV, PET-GTV, ratio, and overlap between MR-GTV and PET-GTV for the less than 14 mL cohort were 9.6 (2.6) mL, 16.7 (10.1) mL, 0.77 (0.40), and 0.47 (0.20), respectively. The PET-GTV overestimated MR-GTV in 4 of the 6 lesions by a mean (SD) of 11.1 (9.4) mL. Among the 14 to 62 mL cohort, the mean (SD) MR-GTV, PET-GTV, ratio, and overlap were 38.6 (14.5) mL, 24.9 (8.6 mL), 1.54 (0.25), and 0.87 (0.08), respectively. The PET-GTV underestimated MR-GTV for 12 tumors by a mean (SD) of 13.7 (8.4) mL. In the 62 mL or more cohort, the mean (SD) MR-GTV, PET-GTV, ratio, and overlap were 85.9 (25.8) mL, 54.3 (14.1) mL, 1.61 (0.35), and 0.87 (0.09), respectively. The PET-GTV underestimated MR-GTV 9 tumors by a mean (SD) of 31.6 (19.5) mL. The ratio and overlap differences were statistically significant among groups (F = 14.619, P < 0.001; F = 25.134, P < 0.001).ConclusionsTumor volume discrepancies were observed between MR-GTV and PET-GTV for cervical cancer. With an increasing tumor volume, there was an increase in the difference between MR-GTV and PET-GTV. In addition, larger tumors had a higher degree of overlap compared with small tumors.

2022 ◽  
Vol 15 ◽  
Author(s):  
Artur Agaronyan ◽  
Raeyan Syed ◽  
Ryan Kim ◽  
Chao-Hsiung Hsu ◽  
Scott A. Love ◽  
...  

The olive baboon (Papio anubis) is phylogenetically proximal to humans. Investigation into the baboon brain has shed light on the function and organization of the human brain, as well as on the mechanistic insights of neurological disorders such as Alzheimer’s and Parkinson’s. Non-invasive brain imaging, including positron emission tomography (PET) and magnetic resonance imaging (MRI), are the primary outcome measures frequently used in baboon studies. PET functional imaging has long been used to study cerebral metabolic processes, though it lacks clear and reliable anatomical information. In contrast, MRI provides a clear definition of soft tissue with high resolution and contrast to distinguish brain pathology and anatomy, but lacks specific markers of neuroreceptors and/or neurometabolites. There is a need to create a brain atlas that combines the anatomical and functional/neurochemical data independently available from MRI and PET. For this purpose, a three-dimensional atlas of the olive baboon brain was developed to enable multimodal imaging analysis. The atlas was created on a population-representative template encompassing 89 baboon brains. The atlas defines 24 brain regions, including the thalamus, cerebral cortex, putamen, corpus callosum, and insula. The atlas was evaluated with four MRI images and 20 PET images employing the radiotracers for [11C]benzamide, [11C]metergoline, [18F]FAHA, and [11C]rolipram, with and without structural aids like [18F]flurodeoxyglycose images. The atlas-based analysis pipeline includes automated segmentation, registration, quantification of region volume, the volume of distribution, and standardized uptake value. Results showed that, in comparison to PET analysis utilizing the “gold standard” manual quantification by neuroscientists, the performance of the atlas-based analysis was at &gt;80 and &gt;70% agreement for MRI and PET, respectively. The atlas can serve as a foundation for further refinement, and incorporation into a high-throughput workflow of baboon PET and MRI data. The new atlas is freely available on the Figshare online repository (https://doi.org/10.6084/m9.figshare.16663339), and the template images are available from neuroImaging tools &amp; resources collaboratory (NITRC) (https://www.nitrc.org/projects/haiko89/).


2011 ◽  
Vol 18 (4) ◽  
pp. 139-146
Author(s):  
Vaida ATSTUPĖNAITĖ ◽  
Algidas BASEVIČIUS ◽  
Adrijus KRIMELIS ◽  
Artūras INČIŪRA ◽  
Daiva VAITKIENĖ

Background. Diffusion-weighted magnetic resonance imaging (DW–MRI) has been employed in the diagnostics of malignant tumors of abdomen and pelvis relatively recently. Nowadays, there exists a particular interest in adaptation DW–MRI for assessing the response of tumors to chemoradiaton therapy. The aim of our study was to compare the mean value of the apparent diffusion coefficient (ADC) in a healthy cervix, cancer-affected cervix and a cervix after chemoradiation therapy, as well as to identify the ADC range typical of cervical cancer. Materials and methods. The study enrolled 108 female patients who underwent pelvic MRI in the Lithuanian University of Health Sciences Kaunas Clinics Hospital in 2008–2010. The study group consisted of 65 patients in whom cervical cancer had been clinically suspected and confirmed by biopsy before MRI examination. All these patients underwent pelvic MRI twice: before the chemoradiation therapy and 6 months after the therapy. The control group consisted of 43 patients in whom cervical cancer had been not suspected and MRI was performed because of other pelvic diseases. Results. The mean ADC value of the study group (0.658 ± 0.118 × 10–3 mm2/s) was lower than of the control group (1.171 ± 0.143 × 10–3 mm2/s) (t = 20.315, p = 0.03). The ADC threshold value of 0.945 × 10–3 mm2/s was defined, differentiating the cancer-affected cervical tissue from the normal. The mean ADC value of the patients who responded to chemoradiation therapy (1.111 ± 0.138 × 10–3 mm2/s) increased and in those who did not respond it remained lower (0.733 ± 0.073 × 10–3 mm2/s) (t = 9.518, p = 0.04). The ADC threshold value of 0.830 × 10–3 mm2/s was defined, differentiating the residual tumor tissue from the healthy cervical tissue after chemoradiation therapy. Conclusions. The ADC value in the case of cervical cancer was significantly lower than in the non-affected cervical tissue. The ADC value increases after effective chemoradiation therapy and becomes closer to the coefficient value of non-affected cervical tissue, but still remains lower. The 0.945 × 10–3 mm2/s ADC threshold was detected while differentiating between cancer-affected and normal cervical tissues, while the ADC threshold was 0.830 × 10–3 mm2/s when differentiating between residual tumor tissue and healthy cervical tissue after chemoradiation therapy at a high sensitivity and specificity. Keywords: diffusion-weighted magnetic resonance imaging, apparent diffusion coefficient, cervical cancer, chemoradiation therapy


2014 ◽  
Vol 24 (4) ◽  
pp. 751-757 ◽  
Author(s):  
Yuki Himoto ◽  
Koji Fujimoto ◽  
Aki Kido ◽  
Noriomi Matsumura ◽  
Tsukasa Baba ◽  
...  

ObjectivesThe purpose of this study was to quantitatively evaluate 3 types of magnetic resonance imaging (MRI) parameters in parallel for the early prediction of neoadjuvant chemotherapy (NACT) effectiveness in cervical cancer—tumor volume parameters, diffusion parameters, and perfusion parameters.Materials and MethodsWe prospectively evaluated 13 patients with International Federation of Gynecology and Obstetrics stage IB to IIB cervical squamous cell carcinoma who underwent 3 serial MRI studies, that is, pretreatment, post–first course NACT, and post–second course NACT followed by radical hysterectomy. We obtained tumor volume parameters, diffusion parameters, and dynamic contrast material–enhanced perfusion parameters quantitatively from pretreatment MRI and post–first course MRI. The correlation of these parameters and the eventual tumor volume regression rate (TVRR) obtained from pretreatment MRI and post–second course MRI before surgery were investigated, statistically based on the Pearson correlation coefficient.ResultsThirteen patients had a total of 39 scans. Early TVRR (r= 0.844;P< 0.001), the fractional volume of the tissue extracellular extravascular space (Ve,r= 0.648;P< 0.05), and the change of Ve during the first course of NACT (r= −0.638;P< 0.05) correlated with eventual TVRR.ConclusionsEarly TVRR, Ve, and the change of Ve could be useful predictors for the treatment effectiveness of NACT. These parameters could help to modify strategy in the early stage of NACT and to choose individualized treatment to avoid the delay of radical treatment, even when NACT is ineffective.


2003 ◽  
Vol 26 (5) ◽  
pp. e163-e168 ◽  
Author(s):  
Kailash Narayan ◽  
Allan McKenzie ◽  
Richard Fisher ◽  
Beatrice Susil ◽  
Tom Jobling ◽  
...  

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