Interventional placement of thin coil shaped implants powered wirelessly for monitoring vital signals and controlling abnormal activities by electro-stimulation.

Various types of implants are being commonly used for monitoring vital signals and controlling the critically ill patient's condition such as arrhythmia, sick sinus syndrome, etc. For implanting these medical devices under the skin, surgery is inevitable. These days many patients are more willing to accept interventional therapies that are less invasive, especially inserting a catheter into a blood vessel or endoscopy through a natural orifice. To be able to use interventional therapy for implanting medical devices, they will need to be small enough to fit them through a catheter or the forceps channel of an endoscope. We evaluated a wirelessly powered prototype of a thin coil shaped (diameter 0.05 inches) implant for electrocardiogram (ECG) monitoring and controlling abnormal heart rhythms. An extracorporeal unit fed power to the sensors and transceiver circuit. We are planning to add sensors for detecting ECG signals and also a pulse generator for transmitting signals to the heart. At 13.6MHz, 10mW was wirelessly transferred from the helical antenna attached to the chest wall of the phantom to the coil's receiving antenna and the power enabled the sensors and circuits to work. Moreover, the coil's receiving antennas worked as stimulating electrodes similar to a pacemaker lead.

1 µm-thickness ultra-flexible and high electrode-density surface electromyogram measurement sheet with 2 V organic transistors for prosthetic hand control.

A 64-channel surface electromyogram (EMG) measurement sheet (SEMS) with 2 V organic transistors on a 1 µm-thick ultra-flexible polyethylene naphthalate (PEN) film is developed for prosthetic hand control. The surface EMG electrodes must satisfy the following three requirements; high mechanical flexibility, high electrode density and high signal integrity. To achieve high electrode density and high signal integrity, a distributed and shared amplifier (DSA) architecture is proposed, which enables an in-situ amplification of the myoelectric signal with a fourfold increase in EMG electrode density. In addition, a post-fabrication select-and-connect (SAC) method is proposed to cope with the large mismatch of organic transistors. The proposed SAC method reduces the area and the power overhead by 96% and 98.2%, respectively, compared with the use of conventional parallel transistors to reduce the transistor mismatch by a factor of 10.

Organic nonvolatile memory transistors for flexible sensor arrays.

Using organic transistors with a floating gate embedded in hybrid dielectrics that comprise a 2-nanometer-thick molecular self-assembled monolayer and a 4-nanometer-thick plasma-grown metal oxide, we have realized nonvolatile memory arrays on flexible plastic substrates. The small thickness of the dielectrics allows very small program and erase voltages (< or = 6 volts) to produce a large, nonvolatile, reversible threshold-voltage shift. The transistors endure more than 1000 program and erase cycles, which is within two orders of magnitude of silicon-based floating-gate transistors widely employed in flash memory. By integrating a flexible array of organic floating-gate transistors with a pressure-sensitive rubber sheet, we have realized a sensor matrix that detects the spatial distribution of applied mechanical pressure and stores the analog sensor input as a two-dimensional image over long periods of time.

Three-dimensional relationship between the conus branch and the precordial leads confirmed by 64-multidetector-row computed tomography.

A 65-year-old man with effort angina pectoris underwent percutaneous coronary intervention of the proximal right coronary artery. The lesion was dilated with a bare-metal stent under wire protection of the conus branch (CB). However, the jailed CB was occluded. Electrocardiogram with conventional precordial leads (V(1) through V(6)) accompanied with the supplementary leads (V(1) through V(6)) positioned 1 intercostal space higher showed marked ST elevation in V(1) through V(3) that was more prominent in V(1) through V(3). The 64-multidetector-row computed tomographic coronary angiography showed recanalization of the CB located just in the center of the V(1), V(2), V(1), and V(2) electrodes.

A large-area wireless power-transmission sheet using printed organic transistors and plastic MEMS switches.

The electronics fields face serious problems associated with electric power; these include the development of ecologically friendly power-generation systems and ultralow-power-consuming circuits. Moreover, there is a demand for developing new power-transmission methods in the imminent era of ambient electronics, in which a multitude of electronic devices such as sensor networks will be used in our daily life to enhance security, safety and convenience. We constructed a sheet-type wireless power-transmission system by using state-of-the-art printing technologies using advanced electronic functional inks. This became possible owing to recent progress in organic semiconductor technologies; the diversity of chemical syntheses and processes on organic materials has led to a new class of organic semiconductors, dielectric layers and metals with excellent electronic functionalities. The new system directly drives electronic devices by transmitting power of the order of tens of watts without connectors, thereby providing an easy-to-use and reliable power source. As all of the components are manufactured on plastic films, it is easy to place the wireless power-transmission sheet over desks, floors, walls and any other location imaginable.

Usefulness of electron beam computed tomography for quantitative estimation of myocardial ischemia in patients.

BACKGROUND: The electron beam computed tomography (EBT) was used as non-invasive methods for estimating mycardial characteristics in patients after onset of Kawasaki disease. METHODS: All of the 22 coronary branches with localized stenosis (LS), and 22 branches without coronary artery lesion after Kawasaki disease were examined for changes of myocardial CT number. In this study, each myocardial region was divided into three parts (endocardial, central, epicardial parts) and the myocardium/lumen (M/L) ratio was calculated. RESULTS: The mean M/L ratio in the endocardial part of early image with LS was significantly lower than the ratios in the other parts of early images with LS (P = 0.0286, P = 0.0069, respectively). and only the mean M/L ratio in the endocardial part was significantly different on images from patients with LS and images from patients without LS (P = 0.0296). Inverse correlations were found in the LS group between coronary artery stenosis rate determined by coronary angiography and M/L ratio in the endocardial part on early images (P = 0.0018, r = -0.614, y = 0.56 -0.605x). CONCLUSIONS: It was possible to quantitatively evalutate myocardial characteristics using EBT. It is suggested that myocardial ischemia progressed from the endocardial region and EBT is useful to detect the endocardial ischemia. We suggested that the rate of coronary stenosis in patients with LS can be estimated by calculating the M/L rations in the endocardial parts of early EBT images. EBT enables accurate evaluation of myocardial characteristics non-invasively.

Sensitivity and specificity of CT in the diagnosis of inflammatory abdominal aortic aneurysms.

PURPOSE: The purpose of this study is to assess the diagnostic ability (sensitivity and specificity) of CT in the diagnosis of inflammatory abdominal aortic aneurysm (IAAA) and to quantitatively evaluate its features. METHOD: A retrospective survey of 355 consecutive patients with abdominal aortic aneurysm and iliac artery aneurysm who underwent CT examination and surgical repair yielded 18 patients with operatively confirmed IAAA. The sensitivity, specificity, and diagnostic accuracy of CT were evaluated in this review. Eighteen IAAAs were then analyzed in terms of distribution and degree of perianeurysmal fibrosis as well as time-dependent change of CT values of the aneurysmal wall on contrast-enhanced CT. Complications related to IAAA were also determined. RESULTS: Fifteen of the 18 cases of IAAA could be easily diagnosed on CT prior to surgical repair. Three false-negative and one false-positive case were found. This gives a sensitivity rate of 83.3% for this imaging technique, with specificity and accuracy rates of 99.7 and 93.7%, respectively. Thickening of the aortic wall was noticed mostly in the anterolateral wall of the aneurysm as compared with the posterior wall. The thickness of the perianeurysmal fibrosis correlated neither with the size of aneurysm nor with the inflammatory reaction such as erythrocyte sedimentation rate, C-reactive protein level, and white blood cell count. CT indicated the complications in 7 of 18 patients with IAAA. These included hydronephrosis, aortoenteric fistula, and infected iliac aneurysm. CONCLUSION: CT scan with contrast enhancement was a highly reliable imaging modality for the diagnosis of IAAA.

[Myocardial fatty acid imaging with 123I-BMIPP in patients with chronic right ventricular pressure overload: clinical significance of reduced uptake in interventricular septum].

Regionally reduced 123I-BMIPP uptake in the interventricular septum (SEP) is observed in some patients with chronic right ventricular (RV) pressure overload. We studied the significance of this finding by comparing it with mean pulmonary arterial pressure (mPAP). 123I-BMIPP SPECT imaging was carried out in 21 patients with pulmonary hypertension (PH; 51(+)-14 years; 11 men and 10 women; 7 with primary pulmonary hypertension, 11 with pulmonary thromboembolism, and 3 with atrial septal defect). mPAP ranged from 25 to 81 mmHg (49 +/- 16 mmHg). Using a midventricular horizontal long-axis plane, regional BMIPP distributions in the RV free wall and SEP were estimated by referring to those in the LV free wall. Count ratios of the RV free wall and SEP to the LV free wall (RV/LV, SEP/LV) were determined by ROI analysis. RV/LV showed a linear correlation with mPAP (r = 0.42). However, SEP/LV was inversely correlated with mPAP (r = -0.49). When SEP/RV was compared among three regions of SEP in each patient, basal SEP/RV was most sensitively decreased in response to increased mPAP (r = -0.70). These results suggest that the assessment of septal tracer uptake in 123I-BMIPP SPECT imaging is useful for evaluating the severity of RV pressure overload in patients with PH.