Incidence of contrast-induced nephropathy after a computed tomography scan.

BACKGROUND AND AIMS: The term contrast-induced nephropathy is used to describe acute deterioration of renal function after the intravenous administration of iodinated contrast material. We aimed to estimate the incidence of contrast-induced nephropathy and to analyze the evolution of different biomarkers of renal function in patients who underwent computed tomography with intravenous contrast administration after premedication with oral hydration and N-acetylcysteine. MATERIAL AND METHODS: This prospective observational study included 112 patients with chronic renal failure (glomerular filtration rate (GFR) 30ml-60ml/min/1.73m2) scheduled for computed tomography with intravenous iodinated contrast material. We recorded demographic variables, dose of contrast material, diabetes mellitus, hypertension, and serum hemoglobin. We measured serum creatinine and GFR after premedication and after the CT examination. We summarized variables as means, standard deviations, and percentages. We used the Wilcoxon and Mann-Whitney tests to compare pre- and post-CT values and Pearson's r to analyze correlations. RESULTS: Incidence acute kidney injury: 0.9%; 95%CI: 0.36-1.4. Mean difference between pre- and post-CT creatinine: 0.04; 95%CI: 0.002-0.09, p<0.004. Mean difference between pre- and post-CT GFR: -3.06; 95%CI: -4.66 to -1.47), p<0.001. CONCLUSIONS: The incidence of contrast-induced nephropathy in patients with chronic renal failure and GFR 30ml-60ml/min/1.73m2 is low. The biomarkers of renal function analyzed improve in patients who receive premedication and the minimum dose of contrast material.

Value of doppler ultrasonography in the study of hemodialysis peripheral vascular access dysfunction.

OBJECTIVE: The main objectives of this study were to evaluate the sensitivity and specificity of duplex Doppler ultrasonography in the study of hemodialysis peripheral vascular access dysfunction and to analyze the resistance index and flow in the afferent artery. MATERIAL AND METHODS: We prospectively studied 178 patients with 178 peripheral vascular accesses that were dysfunctional in at least three consecutive hemodialysis sessions. Patients underwent duplex Doppler ultrasonography and clinical and laboratory follow-up for three months (provided angiography findings were negative). We calculated the sensitivity, specificity, predictive values, and coefficients of probability. We studied the morphology of the afferent artery, the arteriovenous anastomosis, and the efferent vein, and we measured the resistance index and the flow of the afferent artery, the diameter of the anastomosis, and the flow and peak systolic velocity in the efferent vein. RESULTS: The final sample consisted of 159 patients. The sensitivity, specificity, positive and negative predictive values, and positive and negative coefficients of probability were 0,98 (95% CI: 0,88-1.00), 0,74 (95% CI: 0,66-0,81), 0,96, 0,82, 3.7, and 0,03, respectively. The resistance index was less than 0,5 in 78.5% of the peripheral vascular accesses with normal function and greater than 0,5 in 86.1% of the dysfunctional peripheral vascular accesses. We found aneurysms in 19 of the native peripheral vascular accesses and pseudoaneurysms in 7 of the prosthetic grafts. Inverted flow was seen in 57 peripheral vascular accesses. CONCLUSION: Duplex Doppler ultrasonography is an efficacious method for detecting and characterizing stenosis and thrombosis in peripheral vascular accesses, and it provides information about the morphology and hemodynamics.

The usefulness of ultrasonography in the diagnosis of carpal tunnel syndrome.

This study assessed the use of ultrasound in the diagnosis of carpal tunnel syndrome and to determine the best ultrasound criterion for diagnosis. Forty wrists of 27 patients with surgically proven moderate and severe carpal tunnel syndrome and 30 wrists of 15 controls were examined. Measurements of the cross-sectional area and the anteroposterior diameter of the median nerve at the inlet and outlet of the carpal tunnel were obtained. Patients also underwent electrophysiological evaluation. Median nerve ultrasonographic measurements were significantly higher in patients. The cross-sectional area of the median nerve at the tunnel inlet was found to be the most useful diagnostic criterion. The optimal cut-off value was 6.5 mm2 (sensitivity 89.5%, specificity 93%). Ultrasound parameters failed to correlate with the electrophysiological findings. The usefulness of ultrasonography in the diagnosis of carpal tunnel syndrome is discussed.

Ultrasonographic and magnetic resonance images of rotator cuff lesions compared with arthroscopy or open surgery findings.

Our purpose was to compare the accuracy of ultrasonography (US) and magnetic resonance (MR) in the diagnosis of rotator cuff injuries (focusing on supraspinatus tears) using arthroscopy or open surgery findings. Using US and MR, we studied all painful shoulders seen during 1998 in our orthopaedic unit. Diagnosis was confirmed in 61 cases. The diagnosis of full thickness rotator cuff tear was highly specific on both imaging techniques (100% for US and 97.1% for MR) but was not as sensitive on US (57.7%) as on MR (80.8%). The diagnosis of partial tear was acceptably specific (67.9% for US and 75.5% for MR) but was not sensitive (overall, 12.5% for US vs 50% for MR). The specificity of a US diagnosis of a tear allows us to recommend surgery, thus making it a good imaging technique for the initial study of painful shoulders. The low sensitivity makes it necessary to undertake an additional MR study. If the MR also discovers no pathology, the sensitivity based on the US and MR images (92.7%) can be sufficient to avoid a false-negative diagnosis.

[Color duplex Doppler ultrasonography in the evaluation of the risk of esophageal varices bleeding in cirrhotic patients]. / Ultrasonografía Doppler dúplex color en la valoración del riesgo de sangrado por varices esofágicas en pacientes cirróticos.

The risk of variceal bleeding (VB) in patients with cirrhosis and esophageal varices may be determined by the portal pressure gradient. The value of Color Duplex Doppler Ultrasonography (CDDU) in the identification of patients at risk for variceal bleeding has been discussed in the literature. In patients with esophageal varices at risk for bleeding, CDDU did not detect patients who presented variceal bleeding during a mean follow-up of 7 months. However, patients with a low Congestion Index (< 0.05) and a mean upper portal vein velocity of > 9 were at lower risk for variceal bleeding. The Congestion Index was higher in patients with bleeding during the follow-up (0.09 vs. 0.057 (p = 0.03) and the mean portal vein velocity was lower in these patients (10.7 vs. 14).