|ECR 2019 / C-2393||
|Magnetic resonance of cervical cancer: relevance of T2-weighted imaging and apparent diffusion coefficient in predicting parametrial invasion|
Aims and objectives
Uterine cervical cancer is the most common gynecologic malignancy and the second most common cancer in women worldwide in terms of incidence and mortality [1, 2]. Cervical carcinoma is staged in accordance with revised Classification of the International Federation of Gynecology and Obstetrics (FIGO) of 2009 Table 1 that recommends performing computed tomography (CT) and/or Magnetic Resonance imaging (MRI), when available. The use of imaging is now complimentary to the clinical examination to assess important prognostic factors such as tumor size, parametrial extension and pelvic side wall invasion, adjacent organ invasion and evaluation of lymph node metastases [2, 3].
CT has limited use in local staging, but it is able to well delineate enlarged lymph nodes, hydronephrosis and distant metastases and moreover permits a complete whole body staging in single exam and simultaneous intra venous contrast media administration. MRI, because of its optimal soft-tissue contrast resolution, is able to clearly define both the local extent of primary tumor and metastatic spread in the pelvis delineating tumor size, parametrial and pelvic sidewall invasion, bladder or rectal infiltration and lymph nodes metastases [1,3].
Especially, the prognostic importance of parametrial invasion (PMI) is well known because it is associated with lymph node metastasis and disease free-survival. Patients without PMI can be treated with less aggressive treatments, while those with PMI undergo chemo radiotherapy or require adjuvant therapy after surgery .
Evaluation of PMI is difficult at clinical examination, depending on the extent of tumor invasion, with studies reporting variable accuracy of 29%-53%. In comparison, MRI is able to depict PMI with 70-97% accuracy - according to the size of the tumor - , 69% sensitivity and 93-97% specificity .
The intactness of the cervical stromal rim on T2-weighted imaging (T2WI), known as the “hypointense rim sign”, has shown excellent negative predictive value of 94-100%, enabling identification of patients who are suitable for radical surgery, which is contraindicated in patient with PMI [1,4]. With disruption of the stromal ring without definite parametrial mass, there may be microscopic invasion understaged by MRI (false-negative findings). Linear stranding around the cervical mass is suggestive of PMI but may be due as well to peritumoral inflammatory tissue and can be a limit of MRI leading to an over-stage of the cervical pathology (false-positive findings) [1,5,6].
In addition to T2WI, the apparent diffusion coefficient (ADC) mapping derived from diffusion-weighted imaging (DWI) on MRI seems to be a very promising emerging technique in the evaluation of cervical cancer. Up to date, just a few recent studies have demonstrated the association between ADC and PMI in cervical cancer, showing that ADC value is significantly lower in cervical cancer with PMI than in cervical cancer without PMI [4,7,8].
The purpose of our study was to evaluate diagnostic value of T2WI and ADC in predicting the presence or absence of PMI in patients with uterine cervical cancer.
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