Malignancy Risk Stratification of Thyroid Nodules According to Echotexture and Degree of Hypoechogenicity: A Multicenter Validation Study

Purpose Various risk stratification systems show some discrepancies in the ultrasound (US) lexicon of nodule echotexture and hypoechogenicity. This study aimed to determine the malignancy risk of thyroid nodules according to their echotexture and degree of hypoechogenicity in a multicenter dataset.Methods From June to September 2015, 5,601 thyroid nodules (≥ 1.0 cm) in 4,989 consecutive patients who underwent thyroid US and with a final diagnoses from 26 institutions were evaluated. Thyroid nodules were stratified according to the US echotexture (homogeneous vs. heterogeneous) and degree of hypoechogenicity (mild, moderate, or marked). We then calculated malignancy risk and compared four subgroups stratified with nodule composition and presence of suspicious features.Results Heterogeneous hypoechoic nodules showed a significantly higher malignancy risk than heterogeneous isoechoic nodules (P ≤ 0.017) except in partially cystic nodules. There was no significant difference in malignancy risk between homogeneous vs. heterogeneous hypoechoic nodules (P ≥ 0.086) and between homogeneous vs. heterogeneous iso- or hyperechoic nodules (P ≥ 0.05) except in partially cystic nodules without suspicious features. The malignancy risks of both homogeneous and heterogeneous iso- or hyperechoic nodules were low to intermediate, depending on the presence of suspicious features. Regarding the degree of hypoechogenicity, there was no significant difference in malignancy risk between markedly and moderately hypoechoic nodules in all subgroups (P ≥ 0.48). Marked or moderately hypoechoic nodules showed a significantly higher risk than mild hypoechoic (P ≤ 0.016) and iso- or hyperechoic (P < .001) nodules. Conclusions The predominant echogenicity effectively stratifies the malignancy risk of nodules with heterogeneous echotexture. For malignancy risk stratification, the degree of nodules’ hypoechogenicity could be grouped as mild vs. moderate to marked hypoechogenicity.

Multicenter Validation of Individual Preoperative Motor Outcome Prediction for Deep Brain Stimulation in Parkinson’s Disease

Background: Subthalamic nucleus deep brain stimulation (STN DBS) is an established therapy for Parkinson’s disease (PD) patients suffering from motor response fluctuations despite optimal medical treatment, or severe dopaminergic side effects. Despite careful clinical selection and surgical procedures, some patients do not benefit from STN DBS. Preoperative prediction models are suggested to better predict individual motor response after STN DBS. We validate a preregistered model, DBS-PREDICT, in an external multicenter validation cohort. Methods: DBS-PREDICT considered eleven, solely preoperative, clinical characteristics and applied a logistic regression to differentiate between weak and strong motor responders. Weak motor response was defined as no clinically relevant improvement on the Unified Parkinson’s Disease Rating Scale (UPDRS) II, III, or IV, 1 year after surgery, defined as, respectively, 3, 5, and 3 points or more. Lower UPDRS III and IV scores and higher age at disease onset contributed most to weak response predictions. Individual predictions were compared with actual clinical outcomes. Results: 322 PD patients treated with STN DBS from 6 different centers were included. DBS-PREDICT differentiated between weak and strong motor responders with an area under the receiver operator curve of 0.76 and an accuracy up to 77%. Conclusion: Proving generalizability and feasibility of preoperative STN DBS outcome prediction in an external multicenter cohort is an important step in creating clinical impact in DBS with data-driven tools. Future prospective studies are required to overcome several inherent practical and statistical limitations of including clinical decision support systems in DBS care.