Background. Cystic Fibrosis (CF) is the most common fatal genetic multisystem disorder. With increased life expectancy CF liver disease (CFLD) is now recognized as a major cause of morbidity and mortality. Sensitivity of current diagnostic tests (clinical examination and biochemistry) is insufficient to allow early detection of CFLD. The aim of this study is to assess the ability of a novel US protocol (Stuart Ultrasound Scoring System (SUSS)) for early diagnosis of CFLD.
Methods. The SUSS protocol includes evaluation of liver edge and texture, size of spleen, portal tracts and hepatic vein waveform. These parameters were scored either as normal (1) or abnormal (2). In addition, the liver was categorized according to the general appearance as normal (A), bright or echogenic (B) and granular (C). A normal score is A5, and any other score is abnormal. SUSS was correlated to blood tests and Aspartate transaminase to platelets ratio index (APRI score).
Results: The protocol was studied in two centers. The initial study was performed on 241 CF patients (group A) and validation of the protocol on 79 patients (group B). Seventy percent of group A and only 41 percent of group B had elevated liver enzymes. In both cohorts the SUSS score in patients with no CFLD was pathological in higher rates than expected (64% group A and 36% group B). When comparing the patients with the normal US scores and the abnormal US scores ALT, AST and GGTP was significantly higher in the abnormal score group, but only slightly higher than normal (medians of 32 vs 38 p=0.002, 20 vs 29 p=0.02, 16 vs 28, p=0.001, accordingly).
Summary and Conclusions: SUSS score is able to detect a patient with structural liver abnormalities which may be due to early CFLD. These patients had normal liver enzymes and were not regarded as having CFLD. Early detection may lead to improved treatment and prognosis. Further evaluation of this scoring system and long term follow-up is warranted.
