Cervical cancer is a major cause of morbidity and mortality worldwide in spite of advances in screening and prevention. The oncologic challenges include early detection, appropriate treatment, and interventions to control the disease. The 2018 FIGO committee has encouraged the use of advanced imaging modalities, including MR imaging, to increase the accuracy of staging and help guide treatment, radiation treatment planning/monitoring, and detection of recurrence [4].
Extensive literature is found supporting the role of MRI in the pretreatment evaluation of patients with cervical cancer. MRI provided detailed findings being an advanced multi-planar multi-parametric modality that made staging and consequently management much easier procedure in a way that overweighs its high cost [7,8,9,10].
On contrast enhanced MRI, cervical cancer presents high signal relative to the low signal of the cervical stroma. Typically, cervical tumors enhance avidly in the early dynamic phase compared to the slight enhancement of the normal cervical epithelium and stroma, permitting distinction of recurrent tumors from radiation fibrosis [11].
In the present study, heterogeneous contrast enhancement was found in 57% of cases. Each of the DWI and DCE-MRI sequences when added to the non-contrast MRI sequences in the estimation of cancer cervix had elicited the same sensitivity value (100%), specificity (50%), and accuracy (97%).
Malignant cervical tissue demonstrates restricted diffusion and hence reduced ADC values when compared to normal tissue. DWI and ADC maps allow differentiation of benign from malignant zones of cervix with high sensitivity and specificity [12].
The current study, DWI-MRI showed sensitivity 100%, specificity 50%, accuracy 97%, PPV 97%, and NPV 100%, compared to DCE-MRI which reported sensitivity 100%, specificity 50%, accuracy 97%, PPV 97%, and NPV 100%. The low percentage of the specificity in this study was due to the low number of the true negative patients. This is in accordance to Chen et al. [13] who found that the sensitivity and specificity of DW-MRI for tumor detection were 100% and 84.8%, respectively.
The current study results are similar to the study carried out by Kuang et al. [14] that included 75 cervical carcinoma and 47 benign cervical lesions (25 cervical leiomyoma, 22 cervical polyps). In their results, DWI-MRI was significantly better than routine MRI and revealed high accuracy (0.95); the diagnostic performance was not significantly different between DWI-MRI and DCE-MRI. In their study, DWI-MRI displayed 95% sensitivity, 96% specificity, 95% accuracy, 97% PPV, and 92% NPV compared to DCE-MRI that displayed sensitivity 96%, specificity 96%, accuracy 96%, PPV 97%, and NPV 94%.
In the present study, the mean ADC value for malignant lesions was 0.82 × 10−3 ± 0.1 SD mm2/s), while the mean ADC value in the control group was 1.56 × 10–3 mm2/s). The ADC value of 1.07 × 10−3 mm2/s was the cut off between benign and malignant cervical lesion by sensitivity 97%, specificity 95.5%, and P value < 0.001. A combination of increased extracellular tortuosity and the ratio of intra- to extracellular water fraction may be the best biological explanation for the decreased ADCs in the cancer tissues [15].
Kuang et al. [14] found that the mean ADC values for cervical carcinoma were 0.916 × 10−3 ± 0.15 SD mm2/s, for cervical leiomyoma 1.396 × 10−3 ± 0.15 SD mm2/s and for cervical polyp (1.426 × 10−3 ± 0.11 SD mm2/s. There were significant differences between the ADC values of cervical cancer and those of benign cervical lesions (leiomyoma and cervical polyps) at both ADC maps (P < 0.001); however, there was no significant difference between cervical leiomyoma and cervical polyps at both ADC maps.
Atstupėnaitė et al. [16] included 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 following therapy. They found that 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), with P value (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 tissue.
Nakmura et al. [17] studied 80 cervical cancer patients who underwent pelvic MRI within the 2 to 4 weeks before radical hysterectomy. They reported that the mean ADC value was (0.852 × 10−3 mm2/s). They also found that well differentiated tumors had higher ADC values than poorly differentiated tumors (1.2 × 10−3 mm2/s vs. 1.1 × 10−3 mm2/s) (P = 0.01).
In this study, we reported no significant difference in ADC between different histological subtypes. ADC mean of keratinized squamous cell carcinoma (K.SCC) was 0.84 × 10−3 mm2/s while that of non-keratinized squamous cell carcinoma (NK.SCC) was 0.76 × 10−3 mm2/s and ADC mean of papillary adenocarcinoma was 0.87 × 10−3 mm2/s. Similar results had been observed in the study done by Payne et al. [18] who reported lower ADCs in cases with cancer cervix compared to normal cervix with no significant difference in ADC values between different histological subtypes.