Diffusion volume (DV) measurement in endometrial and cervical cancer: A new MRI parameter in the evaluation of the tumor grading and the risk classification
Keywords: Mri, Dwi, Adc Maps, Diffusion Volume, Cervical Cancer, Endometrial Cancer, Adult, Aged, Segmentation, Cancer Classification, Cancer Grading, Cancer Risk, Cancer Staging, Diffusion Weighted Imaging, Endometrium Cancer, Female, High Risk Population, Histopathology, Human, Kruskal Wallis Test, Major Clinical Study, Nuclear Magnetic Resonance Imaging, Priority Journal, Receiver Operating Characteristic, Uterine Cervix Cancer, Analysis Of Variance, Diffusion Magnetic Resonance Imaging Methods, Endometrial Neoplasms Pathology, Image Interpretation, Computer-Assisted, Middle Aged, Neoplasm Grading, Observer Variation, Sensitivity And Specificity, Tumor Burden, Uterine Cervical Neoplasms Pathology, Article, Automation, Computer Assisted Diagnosis, Endometrium Tumor, Procedures, Tumor Volume, Uterine Cervix Tumor
Affiliations: *** IBB - CNR ***
IBB CNR, Napoli, Italy
Dipartimento di Scienze Biomediche Avanzate, Sezione di Radiologia, Università di Napoli “Federico II”, Napoli, Italy
IRCCS CROB, Rionero in Vulture, Italy
IRCCS SDN, Napoli, Italy
References: Not available.
Diffusion volume (DV) measurement in endometrial and cervical cancer: A new MRI parameter in the evaluation of the tumor grading and the risk classification
Highlights
•
The DV includes all the voxels within a tumor with ADC values below a threshold.
•
The DV selects higher cellular density voxels indicating the active tumor burden.
•
The DV of cervical and endometrial cancer allows stratification of G-grade and risk groups.
•
The DV works better than the ADC values and T2 volume in the above stratification.
•
The intra- and inter-observer variability of DV is excellent.
Abstract
Purpose
A new MRI parameter representative of active tumor burden is proposed: diffusion volume (DV), defined as the sum of all the voxels within a tumor with apparent diffusion coefficient (ADC) values within a specific range. The aims of the study were: (a) to calculate DV on ADC maps in patients with cervical/endometrial cancer; (b) to correlate DV with histological grade (G) and risk classification; (c) to evaluate intra/inter-observer agreement of DV calculation.
Materials and methods
Fifty-three patients with endometrial (
n
= 28) and cervical (
n
= 25) cancers underwent pelvic MRI with DWI sequences. Both endometrial and cervical tumors were classified on the basis of G (G1/G2/G3) and FIGO staging (low/medium/high-risk).
A semi-automated segmentation procedure was used to calculate the DV. A freehand closed ROI outlined the whole visible tumor on the most representative slice of ADC maps defined as the slice with the maximum diameter of the solid neoplastic component. Successively, two thresholds were generated on the basis of the mean and standard deviation (SD) of the ADC values: lower threshold (LT = “mean minus three SD”) and higher threshold (HT = “mean plus one SD”). The closed ROI was expanded in 3D, including all the contiguous voxels with ADC values in the range LT-HT × 10–3 mm
2
/s.
A Kruskal–Wallis test was used to assess the differences in DV among G and risk groups.
Intra-/inter-observer variability for DV measurement was analyzed according to the method of Bland and Altman and the intraclass-correlation–coefficient (ICC).
Results
DV values were significantly different among G and risk groups in both endometrial (
p
< 0.05) and cervical cancers (
p
≤ 0.01). For endometrial cancer, DV of G1 (mean ± sd: 2.81 ± 3.21 cc) neoplasms were significantly lower than G2 (9.44 ± 9.58 cc) and G3 (11.96 ± 8.0 cc) ones; moreover, DV of low risk cancers (5.23 ± 8.0 cc) were significantly lower than medium (7.28 ± 4.3 cc) and high risk (14.7 ± 9.9 cc) ones. For cervical cancer, DV of G1 (0.31 ± 0.13 cc) neoplasms was significantly lower than G3 (40.68 ± 45.65 cc) ones; moreover, DV of low risk neoplasms (6.98 ± 8.08 cc) was significantly lower than medium (21.7 ± 17.13 cc) and high risk (62.9 ± 51.12 cc) ones and DV of medium risk neoplasms was significantly lower than high risk ones.
The intra-/inter-observer variability for DV measurement showed an excellent correlation for both cancers (ICC ≥ 0.86).
Conclusions
DV is an accurate index for the assessment of G and risk classification of cervical/endometrial cancers with low intra-/inter-observer variability.
Diffusion volume (DV) measurement in endometrial and cervical cancer: A new MRI parameter in the evaluation of the tumor grading and the risk classification
Diffusion volume (DV) measurement in endometrial and cervical cancer: A new MRI parameter in the evaluation of the tumor grading and the risk classification