Development of a device for immobilization of head and correlation of functional-anatomical brain images.

BACKGROUND: The excellent resolution of brain imaging modalities has important contributions in the diagnosis of brain diseases. However, involuntary movement by the patient may cause poor image quality. In this study, we developed a device to help keep a patient's head immobilized during brain image acquisition, for comparison between each follow-up study, and for functional-anatomical image correlation. METHODS: This device includes an acrylic material head supporter and a thermoplastic material facemask. The head supporter and the facemask can be firmly attached as a whole to support the head in a fixed position. Two capillary tubes filled with technetium-99m solution were placed perpendicularly on one side of the facemask as fiducial for imaging correlation between different studies. Ten patients, who each had two technetium-99m hexamethyl propyleneamine oxime (99mTc-HMPAO) brain single photon emission computer tomography (SPECT), were tested with this device for imaging. RESULTS: Three-dimensional cine motion and sectional imaging were displayed and confirmed head immobilization in all of these studies. In addition, the 99mTc fiducial were useful in the comparison of head positions among the different studies. In five subjects, the device also proved to be useful in functional-anatomical correlation among SPECT, magnetic resonance imaging (MRI), and computed tomography (CT) images. CONCLUSION: In conclusion, this device has been developed and found to be useful in (1) keeping patient's head immobilization, (2) keeping consistent head position for follow-up studies, and (3) SPECT, MRI and CT functional-anatomical imaging correlation.

[First pass radionuclide angiography in the measurement of the left ventricular ejection fraction--assessment of the accuracy of a new method].

This study was designed to validate a modified computer program in evaluating the left ventricular ejection fraction (LVEF) by first pass radionuclide cardioangiography. This program was modified by us from the pulmonary background subtraction method postulated by Gal et al. Another three programs supplied by the computer company were included in the study to compare the accuracy among these program algorithms. From the results of 97 patients undergoing first pass and gated equilibrium cardiac blood pool studies, we found that the measured ejection fractions by these four programs were all correlated well with those by the equilibrium gated cardiac program (r = 0.81-0.86). The latter was already confirmed and verified in a previously published work using a Vanderbilt dynamic cardiac phantom. Except for the LVEF values obtained from our modified program, all values obtained from the other three programs were significantly lower than those obtained by the verified equilibrium program. However, the results obtained from our designed program correlated well with those obtained from the equilibrium method. Furthermore, none of the patient's raw data was rejected by this modified program.