Role of MRI in diagnosing the primary site of origin in indeterminate cases of uterocervical carcinomas: a systematic review and meta-analysis

Abstract

Objective: To perform a literature review assessing role of MRI in predicting origin of indeterminate uterocervical carcinomas with emphasis on sequences and imaging parameters. Methods: Electronic literature search of PubMed was performed from its inception until May 2020 and PICO model used for study selection; population was female patients with known/clinical suspicion of uterocervical cancer, intervention was MRI, comparison was by histopathology and outcome was differentiation between primary endometrial and cervical cancers. Results: Eight out of 9 reviewed articles reinforced role of MRI in uterocervical primary determination. T2 and Dynamic contrast were the most popular sequences determining tumor location, morphology, enhancement, and invasion patterns. Role of DWI and MR spectroscopy has been evaluated by even fewer studies with significant differences found in both apparent diffusion coefficient values and metabolite spectra. The four studies eligible for meta-analysis showed a pooled sensitivity of 88.4% (95% confidence interval 70.6 to 96.1%) and a pooled specificity of 39.5% (95% confidence interval 4.2 to 90.6%). Conclusions: MRI plays a pivotal role in uterocervical primary determination with both conventional and newer sequences assessing important morphometric and functional parameters. Socioeconomic impact of both primaries, different management guidelines and paucity of existing studies warrants further research. Prospective multicenter trials will help bridge this gap. Meanwhile, individual patient database meta-analysis can help corroborate existing data. Advances in knowledge: MRI with its classical and functional sequences helps in differentiation of the uterine ‘cancer gray zone’ which is imperative as both primary endometrial and cervical tumors have different management protocols.

Preliminary Application of Magnetization Transfer Imaging in the Study of Normal Uterus and Uterine Lesions

“…Adenocarcinoma originates from endometrial cells with abundant glandular structures and has the ability to secrete mucins ( 28 ), potentially leading to higher MTR values. A systematic review and meta-analysis ( 10 ) confirmed that the pooled sensitivity and specificity for MRI in predicting origin of indeterminate uterocervical cancers were 0.884 and 0.395, respectively. Of which, T2WI and DCE-MRI were the most popular sequences, and DWI sequence and apparent diffusion coefficient values were also valuable.…”

“…Tissue contrast mechanism of conventional MRI is relying on density, T1 and T2 relaxation properties of free water protons, and diffusion properties of water molecules ( 19 ). It has a high sensitivity in detecting pathological tissue, but pathological specificity is poor ( 10 ). Except for leiomyoma and adenomyosis, almost all common uterine lesions show low signal intensity on T1WI and high signal intensity on T2WI ( 9 ).…”

“…Conventional T2-weighted imaging (T2WI) and some functional MRI sequences such as diffusion-weighted imaging (DWI) and dynamic contrast-enhanced MRI (DCE-MRI) have been widely explored for diagnosing uterine diseases ( 9 ). However, because of coexisting multiple lesions, extensive lesions, metratrophia, and other factors, the accuracy of MRI in identifying different primary uterine lesions needs further improvement, especially for cancers involving both cervix and the lower uterine segment, leading to ambiguous diagnosis of endometrial and cervical cancer ( 10 ). Because both of them showed high signal on T2WI, obvious high signal on DWI, and mild enhancement on contrast-enhanced MRI (CE-MRI) ( 11 ).…”