Seismocardiography (SCG), a representation of mechanical heart motion, may more accurately determine periods of cardiac quiescence within a cardiac cycle than the electrically derived electrocardiogram (EKG) and, thus, may have implications for gating in cardiac computed tomography. We designed and implemented a system to synchronously acquire echocardiography, EKG, and SCG data. The device was used to study the variability between EKG and SCG and characterize the relationship between the mechanical and electrical activity of the heart. For each cardiac cycle, the feature of the SCG indicating Aortic Valve Closure was identified and its time position with respect to the EKG was observed. This position was found to vary for different heart rates and between two human subjects. A color map showing the magnitude of the SCG acceleration and computed velocity was derived, allowing for direct visualization of quiescent phases of the cardiac cycle with respect to heart rate.

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Objectives To evaluate whether the presence of facial photographs obtained at the point-of-care of portable radiography leads to increased detection of wrong-patient errors. Materials and Methods In this IRB-approved study, 166 radiograph-photograph combinations were obtained from 30 patients. Consecutive radiographs from the same patients resulted in 83 unique pairs (i.e., a new radiograph and prior, comparison radiograph) for interpretation. To simulate wrong-patient errors, mismatched pairs were generated by pairing radiographs from different patients chosen randomly from the sample. Ninety radiologists each interpreted a unique randomly chosen set of 10 radiographic pairs, containing up to 10% mismatches (i.e., error pairs). Radiologists were randomly assigned to interpret radiographs with or without photographs. The number of mismatches identified and interpretation times were recorded. Results Ninety radiologists with 21 ± 10 (mean ± SD) years of experience were recruited to participate in this observer study. With the introduction of photographs, the proportion of errors detected increased from 31% (9/29) to 77% (23/30) (P = 0.006). The odds ratio for detection of error with photographs to detection without photographs was 7.3 (95% CI: 2.29, 23.18). Observer qualifications, training or practice in cardiothoracic radiology did not influence sensitivity for error detection. There is no significant difference in interpretation time for studies without photographs and those with photographs (60 ± 22 seconds vs 61 ± 25 seconds; P=0.77). Conclusion In this observer study, facial photographs obtained simultaneously with portable chest radiographs increased the identification of any wrong-patient errors, without substantial increase in interpretation time. This technique offers a potential means to increase patient safety through correct patient identification.

To more accurately trigger cardiac computed tomography angiography (CTA) than electrocardiography (ECG) alone, a sub-system is proposed as an intermediate step toward fusing ECG with seismocardiography (SCG). Accurate prediction of quiescent phases is crucial to prospectively gating CTA, which is susceptible to cardiac motion and, thus, can affect the diagnostic quality of images. The key innovation of this sub-system is that it identifies the SCG waveform corresponding to heart sounds and determines their phases within the cardiac cycles. Furthermore, this relationship is modeled as a linear function with respect to heart rate. For this paper, B-mode echocardiography is used as the gold standard for identifying the quiescent phases. We analyzed synchronous ECG, SCG, and echocardiography data acquired from seven healthy subjects (mean age: 31; age range: 22–48; males: 4) and 11 cardiac patients (mean age: 56; age range: 31–78; males: 6). On average, the proposed algorithm was able to successfully identify 79% of the SCG waveforms in systole and 68% in diastole. The simulated results show that SCG-based prediction produced less average phase error than that of ECG. It was found that the accuracy of ECG-based gating is more susceptible to increases in heart rate variability, while SCG-based gating is susceptible to high cycle to cycle variability in morphology. This pilot work of prediction using SCG waveforms enriches the framework of a comprehensive system with multiple modalities that could potentially, in real time, improve the image quality of CTA.

Frequency shift color Doppler imaging was assessed in conjunction with patient age and gray scale (GS) features for discriminating benign from malignant breast masses. Thirty-eight women with sonographically detected masses scheduled for biopsy were evaluated using a 6-to 13-MHz scan head, and the masses were delineated in ultrasonographic image volumes. Vascularity in and around each mass was quantified using speed-weighted pixel density (SWD). Gray scale features were ranked visually on a linear scale. Combinations of indices were compared with histologic findings (18 benign and 20 malignant). Receiver operating characteristic analysis ranked performance in decreasing order from the SWD-Age-GS index, to SWD-GS, SWD-Age, Age-GS, GS criteria, SWD, and Age. At 100% sensitivity, SWDAge-GS, SWD-GS, and SWD-Age discriminated benign from malignant masses with specificities of 94%, 89%, and 72%, respectively. These results indicate significant improvement in ultrasonographic discrimination of sonographically detected breast masses by combining the vascularity measure SWD with age and GS criteria. Key words: Doppler ultrasonography; image processing; three-dimensional imaging; breast cancer; vascularity; angiogenesis. Abbreviations Az, area under the receiver operating characteristic curve; GS, gray scale; ROC, receiver operating characteristic; ROI, region of interest; ROR, radiologist's region of interest; SWD, speedweighted pixel density; 3D, three-dimensional lthough their benefits far outweigh the risk of modest radiation exposure, mammograms do present some shortcomings. Screening mammograms have sensitivities of 68% to 85% 1 and 32% specificity, 2 resulting in a number of unnecessary biopsies on benign masses. Development of cost-effective, noninvasive adjunctive techniques to mammography for differentiating benign from malignant masses would significantly reduce the number of biopsies yielding negative results.Capitalizing on the high quality of gray scale (GS) images produced by current ultrasonographic equipment, researchers have investigated discrimination techniques based on GS measures. Results describing visual

The authors report on an actuated positioning device for a cochlear prosthesis insertion procedure. The device consists of multiple high-aspect ratio fluidic actuator chambers integrated with a high-density silicon cochlear electrode array and manufactured in a taperedhelix form. Actuation chambers with cross-sectional sizes as small as 40 · 200 lm and lengths of 30 mm have been fabricated using flexible polymers. The device will allow for low-resistance basilar insertion of a stimulating electrode array into the cochlea providing for deep, perimodiolar position considered most beneficial for auditory nerve stimulation, while minimizing intracochlear trauma. Experimental measurements, FEA analysis, and modeling demonstrate a viable and appropriate actuation method for a cochlear implant procedure.

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