The role of contrast-enhanced computed tomography to detect renal stones.

PURPOSE: To investigate the detectability of renal stones in corticomedullary and nephrographic phases on contrast-enhanced computed tomography (CT). METHODS: All consecutive patients between January 2012 and February 2016 undergoing CT of the kidneys according to our department's standard four-phase protocol and having at least one stone in the NC-phase (NCP) were included. Fifty patients with altogether 136 stones were eligible. Two radiologists in consensus evaluated the NCP from each examination and documented the number, location, and size of stones. Three abdominal radiologists blinded to the findings of the NCP reviewed independently the corticomedullary and nephrographic phases on two different occasions. They reported the number and location of stones in each kidney. For the inter-observer agreement the intra-class correlation coefficient (ICC) was estimated. The detection rate of renal stones was calculated for the three radiologists and compared between the two contrast-enhanced phases and the results were analyzed with concern to the size of the stones. RESULTS: The ICC was 0.86. There was no statistically significant difference between corticomedullary and nephrographic phases (p = 0.94). The detection rate for stones measuring 3-5 mm was 82-88% and 98% for stones ≥ 6 mm. CONCLUSION: The detectability of renal stones ≥ 6 mm on contrast-enhanced CT is extremely high. This means that stones with a higher risk of not passing spontaneously can be safely diagnosed.

Evaluation of a diagnostic algorithm for Heparin-Induced Thrombocytopenia.

INTRODUCTION: Heparin-Induced Thrombocytopenia (HIT) is a rare but serious immune-mediated complication of heparin treatment. HIT is characterized by an acute, transient prothrombotic state combined with thrombocytopenia and is caused by platelet-activating IgG antibodies that bind to complexes of heparin and platelet factor 4. The diagnosis of HIT relies on clinical presentation and the demonstration of HIT antibodies. One approach to improve the efficacy of laboratory analysis is to use a diagnostic algorithm. AIM: To evaluate one diagnostic algorithm for HIT where the 4 T's clinical risk score is combined with immunochemical and/or functional assays. MATERIALS AND METHODS: The quality of the diagnostic algorithm was retrospectively evaluated in 101 patients with suspected HIT. Laboratory results obtained from the diagnostic algorithm were compared to Heparin-Induced Platelet Aggregation (HIPA) and clinico-pathological evaluation of patients' medical records. RESULTS: We found that the algorithm had a diagnostic efficacy of 94%, with specificity of 94% and sensitivity 94%. Positive likelihood ratio (LR+) was 16.0, and the negative likelihood ratio (LR-) 15.5. The efficacy of PaGIA (n=95) was 0.46, and IgG-specific HPF4-abELISA (n=54) was 0.87. CONCLUSIONS: The diagnostic algorithm for HIT is sufficiently accurate and leads to in overall faster results and decreased cost of analysis. The weakest link of the algorithm is the risk of miscalculated 4T's scores, which is inevitably exacerbated by the insufficient experience most clinicians have with HIT. This highlights the importance of clear instructions from the laboratory and coagulation clinic.