Schistosoma mansoni: magnetic resonance analysis of liver fibrosis according to WHO patterns for ultrasound assessment of schistosomiasis-related morbidity

Abstract

For the last two decades, ultrasound (US) has been considered a surrogate for the gold standard in the evaluation of liver fibrosis in schistosomiasis. The use of magnetic resonance imaging (MRI) is not yet standardised for diagnosing and grading liver schistosomal fibrosis. The aim of this paper was to analyse MRI using an adaptation of World Health Organization (WHO) patterns for US assessment of schistosomiasis-related morbidity. US and MRI were independently performed in 60 patients (42.1 ± 13.4 years old), including 37 men and 23 women with schistosomiasis. Liver involvement appraised by US and MRI was classified according to the WHO protocol from patterns A-F. Agreement between image methods was evaluated by kappa index (k). The correlation between US and MRI was poor using WHO patterns [k = 0.14; confidence interval (CI) 0.02; 0.26]. Even after grouping image patterns as "A-D", "Dc-E" and "Ec-F", the correlation between US and MRI remained weak (k = 0.39; CI 0.21; 0.58). The magnetic resonance adaptation used in our study did not confirm US classification of WHO patterns for liver fibrosis

Revisiting the concept of hepatosplenic schistosomiasis and its challenges using traditional and new tools

“…It uses strong magnetic fi elds and non-ionizing radiation in the radio frequency range, in contrast to CT scans and traditional X-rays, which both use ionizing radiation. Contrast agents may be injected intravenously to enhance the appearance of blood vessels, tumors or infl ammation [36][37][38][39][40][41][42][43] . …”

“…The World Health Organization (WHO) grading of liver fi brosis by US should be reevaluated and used carefully in the defi nition of the severity of hepatosplenic schistosomiasis. Papers published using the WHO classifi cation should also be revised 37,38,41 . The characteristic periportal fi brosis (diagnosed by US, MRI or histology) associated with evidence of portal hypertension (large spleen, esophageal varices and collateral vessels) should be suffi cient to defi ne disease severity and indicate surgical intervention, as necessary.…”

A avaliação ultrassonográfica da esquistossomose mansônica

“…On the other hand, the study has found the low sensitivity of the method for detecting periportal fibrosis in patients with hepatosplenic schistosomiasis mansoni from endemic regions and possibly resulting from milder disease presentations, maybe indicating the limited capacity of US to detect earlier stages of periportal fibrosis. Some studies have demonstrated a low intermethod agreement between US and MRI (considered as the most effective noninvasive method in the assessment of periportal fibrosis) in the evaluation of mild degrees of periportal fibrosis (14,15) , justifying the results observed by Fernandes et al…”

Liver ultrasound elastography for the evaluation of periportal fibrosis in schistosomiasis mansoni: A cross-sectional study

“…US scan has become the most consolidated tool for evaluation of PPF in endemic areas because it shows practical usefulness, satisfactory interobserver agreement, and enables data comparison on international scale [6][7][8]21]. Despite the widespread use of US for diagnosing and monitoring changes caused by PPF, its use has some limitations, since it is a subjective method and requires physician expertise to apply the WHO Niamey-Belo Horizonte protocol.…”

“…Among the 358 patients included, 222 (62.0%) were women, with a median age of 54 (ranging 18-92) years. 6 The diagnosis of schistosomiasis mansoni infection was based on clinical history of contact with fresh water sources from endemic areas, reports of prior treatment with praziquantel, along with US findings of PPF. Patients were classified into two groups according to the PPF patterns using Niamey's classification: 86 patients with mild PPF (pattern C) and 272 patients with significant PPF (patterns D, E and F).…”