![]() Despite developments in the automation of TCD operation, inter-rater variability is an obstacle that will persist while human involvement is required. 10 These findings further underscore the importance of precise TCD exam execution. was a significant difference in sensitivity of TCD measurements by trained operators (100%) compared to untrained operators (40%). 10, 11, 22 For example, a comparison of mCBFV measurements between an expert and untrained sonographer revealed a large and significant difference in these values (-26.0☒7.4 cm/s, p<0.001). Inter-rater agreement of mCBFV measurements between two human operators has been studied previously, with varying levels of agreement depending on the level of training and experience. The findings of this work align well with previous investigations of variability in TCD measurements between expert sonographers. For each scan region j, we consider the signal pairs ( m C B F V r t c d j, m C B F V r v t j) and ( S Q A r t c d j, S Q A r v t j) for which we report the mean accuracy ratio (MAR) and Bland-Altman mean difference (MD) defined as: Similarly, we define m C B F V r t c d j and S Q A r t c d j for the rTCD system. For each scan region j, denote the signals acquired by the RVT can be defined as R V T j = ) that is the highest velocity signal may not be the same signal that has the highest signal quality assessment. Note that a single subject has two scan regions corresponding to their left and right temporal regions, so each subject contributes two indices to the analysis (e.g. We enumerate the unilateral patient scan regions by an index set denoted by j in the following equations. All data processing and analysis were performed using Python (v2.7) with major data science libraries, such as scipy, pandas, matplotlib, and scikit-learn. The NovaGuide system was restricted to 10 minutes total time to conduct the bilateral TCD examination. 14, 15 Each candidate signal is evaluated/recorded for 10 seconds. The evaluation determination is made automatically by a previously presented method which incorporates several relevant metrics for signal quality. The NovaGuide will concurrently search bilaterally, providing multiple signals for consideration as it optimizes for the highest quality signal. The system user then starts the examination by pushing a “start button” on the exam screen. The NovaGuide software then automatically registers the fiducials placed on the subject using image processing techniques from images captured by the system’s bilateral cameras located adjacent to the probes. Consistent with manual TCD examinations, TCD gel is applied to the temporal region before the exam is initiated. Following placement of the fiducials, the subject is placed within the NovaGuide head cradle in the supine position. For conducting a NovaGuide exam, two fiducial stickers are placed on each side of the subject’s head, one on the corner of the eye and the other on the tragus of the ear. Immediately after the RVT completed the manual TCD examination, the NovaGuide rTCD was set up on the subject while still in supine position ( Fig.
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