DIAGNOSTIC ACCURACY OF CONTRAST ENHANCED MRI IN DETECTION OF VASCULAR INVASION BY LIMB SARCOMAS: EXPERIENCE FROM A TERTIARY CARE CANCER HOSPITAL.

Abstract

Introduction:

Vascular invasion by primary soft tissue or bony sarcomas is rare yet very important feature in terms of management decisions. MRI is considered modality of choice in most of the musculoskeletal tumors because of its capability to better delineate anatomy, extent of intraosseous and intramuscular tumor involvement and tumoral relationship with adjacent neurovascular bundles. In the past years, vascular invasion was evaluated by angiography was considered as imaging modality of choice. However, since the past decade, contrast enhanced MRI is largely replacing the angiography as imaging modality as it is cheaper, non-invasive and does not use ionizing radiations and reduced imaging time.

Purpose: To evaluate the diagnostic accuracy of contrast-enhanced MRI in the detection of vascular invasion in cases of bone and soft tissue sarcomas of limbs taking surgical findings as gold standard.

Materials and Methods: After the approval from the ethical review board, reterospective study was performed from the period of 1^st January 2018 to 30^th June 2018 using the database of Shaukat Khanum Memorial Cancer Hospital and Research Center. Patients with biopsy-proven sarcoma of bone or soft tissues of limbs were taken and their pre-operative MRI scans were re-evaluated for the MRI features of vascular invasion. Findings of MRI will then be correlated with surgical findings and will be labelled as positive or negative on the basis of per-operative presence or absence of vascular invasion.

Results:

A total of 50 sarcoma patients were included in this study. Out of these 50 patients, vascular encasement by tumor was reported in 7 cases (14%) on baseline MRI; while 8 patients (16%) had vascular encasement on surgery. 1 case (2%) was reported as positive for vascular encasement on MRI but was negative on surgery (false positive). 2 cases (4%) were reported to be negative for vascular encasement on MRI but were positive on surgery (false negative). 40 cases (80%) showed no vascular involvement on both MRI and on surgery. Pearson chi-square p-value was calculated to be 0.000 which confirms the significance of the results). The sensitivity of MRI in detecting vascular invasion was calculated to be 77.78%, specificity was 97.56% and diagnostic accuracy was 94.00%

Conclusion:

Contrast enhanced MRI proved to be reliable and an accurate imaging modality in the evaluation of sarcomas and is highly sensitive and specific in the evaluation of neurovascular encasement.

Keywords: Sarcoma, vascular invasion, MRI.