Role of Non invasive Imaging in Characterisation of Soft Tissue Vascular Anomalies: Comparison of Ultrasound with Contrast Enhanced Magnetic Resonance Imaging

Abstract

Introduction: Soft tissue vascular anomalies present a diagnostic challenge. In these anomalies, imaging is crucial for therapeutic planning and improvement of prognosis. Ultrasound (US) and Contrast-Enhanced Magnetic Resonance Imaging (CEMRI) are both widely utilised and are valuable imaging modalities, both having distinct advantages and limitations in evaluation of such lesions. Aim: To evaluate soft tissue vascular anomalies using US and CEMRI and assess their agreement in characterisation of these lesions. Materials and Methods: The prospective study included 75 patients with vascular anomalies evaluated by means of US and CEMRI: 71 underwent both US and MRI, three underwent US alone, and one patient underwent MRI alone. Patients of all ages were included. Lesions were characterised based on imaging findings and vascular perfusion characteristics. Histopathological evaluation was done in all patients. Receiver Operating Characteristic (ROC) analysis was used for differentiating data. The agreement of US and CEMRI with histopathological diagnosis were assessed using kappa statistics. Results: Among the soft tissue vascular anomalies, 17 were haemangiomas, 55 were vascular malformations and 3 were other vascular tumours. Majority of the lesions were venous malformations (n=26; 34.66%). A cut-off value of 17.5 cm/sec of peak venous velocity using Colour Doppler showed 100% sensitivity in differentiating Arterio-Venous Malformations (AVM) from haemangiomas using ROC curves. Agreement expressed as kappa was 0.884 (95% CI 0.794-0.973) for US and 0.923 (95% CI 0.850-0.996) for CEMRI demonstrating near perfect agreement with histopathology in both. Conclusion: The findings of this study indicate that both US and CEMRI are accurate in detection and characterisation of soft tissue vascular anomalies showing comparable level of agreement. US may be the preferred imaging modality as it is widely available, relatively inexpensive and non invasive. Contrast enhanced MRI may be reserved as a complementary technique in cases wherein lesion categorisation or extent is ambiguous during diagnosis.