Improved Carotid Stenosis Quantification on Novel 4D/3D-Doppler Ultrasonography Indexing to the Common Carotid Artery.

PURPOSE: The accuracy of internal carotid artery stenosis (ICAS) quantification depends on the method of stenosis measurement, impacting therapeutic decisions and outcomes. The NASCET method references the stenotic to the distal ICAS lumen, the ECST method to the local outer and the common carotid artery (CC) method to the CC diameter. Direct morphometric stenosis measurement with four-dimensionally guided three-dimensional ultrasonography (4D/3DC-US) demonstrated good validity for the commonly used NASCET method. The NASCET definition has clinically relevant drawbacks. Our purpose was to investigate the validity of the ECST and CC methods. MATERIALS AND METHODS: 4D/3DC-US percent-stenosis measures of 103 stenoses (80 patients) were compared to quantitative catheter angiography and duplex ultrasonography (DUS) in a blinded fashion. RESULTS: The 4D/3DC-US versus angiography intermethod standard deviation of differences (SDD, n = 103) was lower for the CC method (5.7 %) compared to the NASCET (8.1 %, p < 0.001) and ECST methods (9.1 %, p < 0.001). Additionally, it was lower than the NASCET angiography interrater SDD of 52 stenoses (SDD 7.2 %, p = 0.047) and non-inferior for the ECST method (p = 0.065). Interobserver analysis of equivalent grading methods showed no differences for the SDDs between angiography and 4D/3DC-US observers (p > 0.076). Binary comparison to angiography showed equal Kappa values > 0.7 and an accuracy ≥ 85 % for the NASCET and CC methods, higher than for the ECST method. The binary accuracy of ICAS grading did not differ from DUS for all methods. CONCLUSION: The new 4D/3DC-US CC method is an accurate and well reproducible alternative to the NASCET and ECST methods and offers potential for clinical application.

Accuracy of Carotid Artery Stenosis Quantification with 4-D-Supported 3-D Power-Doppler versus Color-Doppler and 2-D Blood Velocity-Based Duplex Ultrasonography.

Assessment of the severity of internal carotid artery stenosis is relevant to therapeutic decisions. Direct measurement of stenosis in static three-dimensionally rendered ultrasonographic color-Doppler images after an orientation with 4-D gray-scale views (4D/3D-C-US) was recently observed to be metrically non-inferior to angiography. In the study described here, power-Doppler (Christian Doppler was a physicist) ultrasonography (4D/3D-P-US) was prospectively compared with angiography, 4D/3D-C-US and 2-D duplex ultrasonography (DUS) in a similar fashion using blinded observers. Percentage stenosis was measured in 36 patients. Continuous percentage stenosis measures (standard deviation of difference and concordance correlation coefficient) between angiography and 4D/3D-P-US did not differ from the results between angiography observers (p > 0.05). Dichotomous diagnosis with 4D/3D-P-US resulted in κ values similar to the inter-rater agreement of angiography and the inter-method agreement of 4D/3D-C-US and DUS compared with angiography. Binary accuracy did not differ between 4D/3D-P-US, 4D/3D-C-US and DUS (p > 0.5). In conclusion, stenosis grading using 4D/3D-P-US exhibited non-inferior inter-method agreement with angiography at good accuracies, similar to 4D/3D-C-US and DUS.

Biometric and mobile gait analysis for early diagnosis and therapy monitoring in Parkinson's disease.

Parkinson's disease (PD) is the most frequent neurodegenerative movement disorder. Early diagnosis and effective therapy monitoring is an important prerequisite to treat patients and reduce health care costs. Objective and non-invasive assessment strategies are an urgent need in order to achieve this goal. In this study we apply a mobile, lightweight and easy applicable sensor based gait analysis system to measure gait patterns in PD and to distinguish mild and severe impairment of gait. Examinations of 16 healthy controls, 14 PD patients in an early stage, and 13 PD patients in an intermediate stage were included. Subjects performed standardized gait tests while wearing sport shoes equipped with inertial sensors (gyroscopes and accelerometers). Signals were recorded wirelessly, features were extracted, and distinct subpopulations classified using different classification algorithms. The presented system is able to classify patients and controls (for early diagnosis) with a sensitivity of 88% and a specificity of 86%. In addition it is possible to distinguish mild from severe gait impairment (for therapy monitoring) with 100% sensitivity and 100% specificity. This system may be able to objectively classify PD gait patterns providing important and complementary information for patients, caregivers and therapists.