ABSTRACT
BACKGROUND: The claw sign is advocated as a discriminant of renal versus non-renal origin of tumours. The accuracy of the claw sign on magnetic resonance imaging (MRI) is unknown and is potentially hindered by the inferior spatial resolution and the larger tumour sizes at presentation in developing countries. OBJECTIVES: To define and evaluate the claw sign in differentiating renal from non-renal retroperitoneal masses in children undergoing MRI. METHODS: A definition of the claw sign was proposed. Magnetic resonance imaging studies, clinical and laboratory records of 53 children were reviewed to test the diagnostic accuracy, inter- and intra-observer reliability. Three tumour-mass interface characteristics, inherent to the claw sign, were tested: (1) a smooth tapering kidney edge blending continuously with the tumour, (2) absence of infolding of the kidney and (3) an obtuse superficial angle. RESULTS: The sensitivity, specificity, negative predictive value and positive predictive values of the claw sign were 97%, 74%, 83% and 94%. The Cohen's kappa values for intra-rater reliability were 0.72 (95% confidence interval 0.54-0.86) for the first reader and 0.83 (0.66-1.00) for the second reader. The Cohen's kappa values for inter-rater reliability were 0.67 (0.50-0.85) and 0.65 (0.44-0.86) for the second reading respectively (p < 0.0001). CONCLUSION: The three tumour-mass interface characteristics investigated are all important characteristics of the claw sign. Intra- and inter-rater reliability is moderate to strong for all characteristics and overall impression of the claw sign. The claw sign is therefore sensitive in the accurate placement of an intra-renal mass but lacks specificity.
ABSTRACT
BACKGROUND: The relevance of clinical data included in blunt trauma referrals for abdominal computed tomography (CT) is not known. OBJECTIVES: To analyse the clinical details provided on free-text request forms for abdominal CT following blunt trauma and assess their association with imaging evidence of intra-abdominal injury. METHOD: A single-institution, retrospective study of abdominal CT scans was performed for blunt trauma between 01 January and 31 March 2018. Computed tomography request forms were reviewed with their corresponding CT images. Clinical details provided and scan findings were captured systematically. The relationship between individual clinical features and CT evidence of abdominal injury was tested using one-way cross tabulation and Fisher's exact test. RESULTS: One hundred thirty-nine studies met inclusion criteria. A wide range of clinical details was communicated. Only clinical abdominal examination findings (p = 0.05), macroscopic haematuria (p < 0.01), pelvic fracture or hip dislocation (p = 0.04) and positive focused assessment with sonography in trauma (p < 0.01) demonstrated an associated trend with abdominal injury. CONCLUSION: Key abdominal examination and basic imaging findings remain essential clinical details for the appropriate evaluation of CT abdomen requests in the setting of blunt trauma. Methods to improve consistent communication of relevant clinical details are likely to be of value.
