Evaluation of dual-energy and perfusion CT parameters for diagnosing solitary pulmonary nodules.

BACKGROUND: To evaluate the correlation and accuracy of dual-energy CT (DECT) (70/Sn150) and low-dose volume perfusion CT (VPCT) parameters for the diagnosis of solitary pulmonary nodules (SPN). METHODS: A total of 15 patients with benign SPN (mean age 56 ± 7 years) and 34 patients with malignant SPN and clinical indication for surgery (mean age 58 ± 6 years) were enrolled from July 2017 to September 2019 at a single institution. All the patients underwent low-dose VPCT with a scan volume of 114 mm on the z-axis and a venous phase enhancement DECT (70/150 Sn) scan just before surgery on the same day. All CT findings were studied in comparison with the pathological results after surgery. Perfusion and dual-energy CT parameters such as blood flow (BF), blood volume (BV), mean transit time (MTT), flow extraction product (FED), pulmonary nodule enhancement peak (PPnod) and iodine concentration (IC) were evaluated as well as t-test, chi-square test, Pearson correlation analysis, and ROC curve analysis to determine the significance of study parameters. RESULTS: The effective radiation dosage of the VPCT and DECT scans were 4.67 ± 0.26 mSv and 0.32 ± 0.10 mSv, respectively. Significant correlations were found between iodine concentration from DECT and VPCT parameters (r = 0.376-0.533, p < 0.05). The sensitivity and specificity of IC to differentiate the SPN were 86.67% and 72.73%, which was slightly lower than that of BV (94.44%, 73.33%), FED (88.89%, 80.00%) and PPnod (94.44%, 80.00%). CONCLUSIONS: VPCT scans have low radiation dosage achieved by shortening the z-axis scan range for assessment of SPN. IC from DECT is significantly correlated with VPCT parameters, and VPCT parameters have better diagnostic performance for SPN than DECT parameters.

Ultrasound-guided fine-needle aspiration for solid thyroid nodules larger than 10 mm: correlation between sonographic characteristics at the needle tip and nondiagnostic results.

The objective of this study was to investigate the effect of the ultrasonographic (US) characteristics and ultrasound elastography (UE) patterns on the probability of a nondiagnostic result when performing ultrasound-guided fine-needle aspiration (UG-FNA) cytological sampling of solid thyroid nodules larger than 10 mm, to determine the efficacy of needle tip localization in UG-FNA. We retrospectively reviewed the cytological results of 710 samples from 355 patients. We compared the US characteristics and UE patterns between nodules with nondiagnostic and diagnostic results, using univariate and multivariate analyses. Among the 710 samples, 81 samples (11.4 %) from 41 patients had nondiagnostic results. According to multivariate analysis, the combinations of hypoechogenicity with avascularity [odds ratio (OR) = 2.42; 95 % confidence interval (CI) 1.37-3.72; p < 0.05], hypoechogenicity with the "hard pattern" (OR = 2.12; 95 % CI 1.58-4.59; p < 0.05), and hypoechogenicity with avascularity and the hard pattern (OR = 2.61; 95 % CI 1.40-5.21; p < 0.05) were risk factors that increased the incidence of nondiagnostic results in UG-FNA. UG-FNA was more likely to yield nondiagnostic results when the needle tip sampling region displayed hypoechogenicity and avascularity in US and the hard pattern in UE.

Conventional ultrasonography and real time ultrasound elastography in the differential diagnosis of degenerating cystic thyroid nodules mimicking malignancy and papillary thyroid carcinomas.

BACKGROUND: To evaluate the diagnostic utility of conventional ultrasonography and real time ultrasound elastography in differentiating degenerating cystic thyroid nodules mimicking malignancy from papillary thyroid carcinoma. METHODS: We retrospectively analyzed conventional ultrasonographic and elastographic characteristics of 19 degenerating cystic thyroid nodules mimicking malignancy in 19 patients, with 30 surgically confirmed PTCs as controls. Based on size, the nodules had been grouped into less than 10mm (group A) and greater than 10 mm (group B). We evaluated conventional parameters and elasticity pattern. Color-scaled elastograms were graded as to stiffness of nodules using an elasticity pattern from I (soft) to IV (stiff). RESULTS: Degenerating cystic thyroid nodules were similar to PTCs in conventional ultrasonographic findings, but the former frequently showed oval to round in shape (group A, 69.2% vs 18.8%, P=0.017; group B, 66.7% vs 7.14%, P=0.017) and punctuate hyperechoic foci (group A, 61.5% vs 0, P<0.001; group B, 50% vs 0, P<0.001). On real time ultrasound elastography, 7 of 13 degenerating cystic thyroid nodules in group A were pattern I, 5 were pattern II, 1 was pattern III. One degenerating cystic thyroid nodule in group B was pattern II, 5 were pattern III. The area under the curve for elastography was 0.98 in group A (sensitivity 92.3%, specificity 100%, P = 0.002), and 0.88 in group B (sensitivity 16.7%, specificity 100%, P = 0.014). CONCLUSIONS: As a dependable imaging technique, elastography helps increase the performance in differential diagnosis of degenerating cystic thyroid nodule and malignancy.