Ultrasound grading of thyroid nodules using the BTA U-scoring guidelines - Is there evidence of intra-and interobserver variability?

INTRODUCTION: U-score ultrasound classification (graded U1-U5) is widely used to grade thyroid nodules based on benign and malignant sonographic features. It is well established that ultrasound is an operator-dependent imaging modality and thus more susceptible to subjective variances between operators when using imaging-based scoring systems. We aimed to assess whether there is any intra- or interobserver variability when U-scoring thyroid nodules and whether previous thyroid ultrasound experience has an effect on this variability. METHODS: A total of 14 ultrasound operators were identified (five experienced thyroid operators, five with intermediate experience and four with no experience) and were asked to U-score images from 20 thyroid cases shown as a single projection, with and without Doppler flow. The cases were subsequently rescored by the 14 operators after six weeks. The first and second round U-scores for the three operator groups were then analysed using Fleiss' kappa to assess interobserver variability and Cochran's Q test to determine any intraobserver variability. RESULTS: We found no significant interobserver variability on combined assessment of all operators with fair agreement in round 1 (Fleiss' kappa = 0.30, p <0.0001) and slight agreement in round 2 (Fleiss' kappa = 0.19, p < 0.0001). Cochran's Q test revealed no significant intraobserver variability in all 14 operators between round 1 and round 2 (all p>0.05). CONCLUSIONS: We found no statistically significant inter- or intraobserver variability in the U-scoring of thyroid nodules between all participants reinforcing the validity of this scoring method in clinical practice, allaying concerns regarding potential subjective biases in reporting.

Lumbar spine fusion and stabilization: hardware, techniques, and imaging appearances.

Stabilization and fusion of the lumbar spine may be performed by using various anterior and posterior surgical techniques and a wide range of devices, including screws, spinal wires, artificial ligaments, vertebral cages, and artificial disks. Because spinal procedures are increasingly common, such devices are seen more and more often in everyday radiologic practice. For evaluation of the postoperative spine, radiography is the modality most commonly used. Computed tomography and magnetic resonance (MR) imaging may be useful alternatives, but MR imaging of the postoperative spine is vulnerable to metal-induced artifacts. For an accurate postoperative assessment of spinal instrumentation and of any complications, it is important that radiologists be familiar with the normal imaging appearances of the lumbar spine after stabilization, fusion, and disk replacement with various techniques and devices.

Management of renal tumors by image-guided radiofrequency ablation: experience in 105 tumors.

AIMS: In this article we present our experience with radiofrequency ablation (RFA) in the treatment of 105 renal tumors. MATERIALS AND METHODS: RFA was performed on 105 renal tumors in 97 patients, with a mean tumor size of 32 mm (11-68 mm). The mean patient age was 71.7 years (range, 36-89 years). The ablations were carried out under ultrasound (n = 43) or CT (n = 62) guidance. Imaging follow-up was by contrast-enhanced CT within 10 days and then at 6-monthly intervals. Multivariate analysis was performed to determine variables associated with procedural outcome. RESULTS: Eighty-three tumors were completely treated at a single sitting (79%). Twelve of the remaining tumors were successfully re-treated and a clinical decision was made not to re-treat seven patients. A patient with a small residual crescent of tumor is under follow-up and may require further treatment. In another patient, re-treatment was abandoned due to complicating pneumothorax and difficult access. One patient is awaiting further re-treatment. The overall technical success rate was 90.5%. Multivariate analysis revealed tumor size to be the only significant variable affecting procedural outcome. (p = 0.007, Pearson chi(2)) Five patients had complications. There have been no local recurrences. CONCLUSION: Our experience to date suggests that RFA is a safe and effective, minimally invasive treatment for small renal tumors.

Intrahepatic arterioportal shunting and anomalous venous drainage: understanding the CT features in the liver.

The increased use of high-contrast volume, arterial-phase studies of the liver has demonstrated the frequent occurrence of arterioportal shunts within both the cirrhotic and non-cirrhotic liver. This article sets out to explain the underlying microcirculatory mechanisms behind these commonly encountered altered perfusion states. Similarly, well-recognised portal perfusion defects occur around the perifalciform and perihilar liver and are largely caused by anomalous venous drainage via the paraumbilical and parabiliary venous systems. The underlying anatomy will be discussed and illustrated. These vascular anomalies are all caused by or result in diminished portal perfusion and are often manifest in the setting of portal venous thrombosis. The evolving concept of zonal re-perfusion following portal vein thrombosis will be discussed.