Biomedical subjects

M Goodsitt

Publications and source records attributed to M Goodsitt.

4 recordsLinked to original sources

PubMed2001

Development of a protocol for coronal reconstruction of the maxillofacial region from axial helical CT data.

Using a fresh frozen cadaver head, a series of axial helical CT scans were obtained using varying imaging parameters both before and after traumatizing the head. The appearance of reformatted coronal images was optimized for the lowest radiation dose. A protocol for imaging the maxillofacial region was developed that produced diagnostic coronal reconstructed images from the axial helical CT data.

Cadaver↗

PubMed1996

Delayed enhanced CT for differentiation of benign from malignant adrenal masses.

PURPOSE: To determine whether adenomas can be differentiated from nonadenomas on 1-hour-delayed enhanced computed tomographic (CT) scans. MATERIALS AND METHODS: In a prospective evaluation of 51 adrenal masses in 39 patients, the CT attenuation was measured at the time of contrast enhancement and 1 hour later. The results were compared for adenomas (n = 41) and metastases (n = 10). RESULTS: On 1-hour-delayed enhanced CT scans, the mean attenuation of the adenomas was 11 HU +/- 13 versus 49 HU +/- 8.3 for metastases (P < .001). At a threshold value of 30 HU, specificity and positive predictive value for the diagnosis of adenoma were 100% with a sensitivity of 95%. The mean decrease in attenuation during the 1-hour delay was 74% +/- 37 for the adenomas versus 31% +/- 28 for the metastases (P < .001). CONCLUSION: CT densitometry on delayed scans obtained 1 hour after contrast enhancement may be useful in characterizing an adrenal mass as an adenoma. When CT is performed with a 150-mL bolus injection of contrast material and with the scanning parameters described in this study, other procedures or imaging studies may be unnecessary if the mass measures less than 30 HU on the delayed scans.

Adenocarcinoma↗

PubMed1995

Normalized average glandular dose in magnification mammography.

PURPOSE: To evaluate the normalized average glandular dose (the average glandular dose per unit entrance skin exposure) in magnification mammography. MATERIALS AND METHODS: Photon transport in the breast was simulated by using Monte Carlo methods. A semielliptical cylinder containing glandular and adipose tissue was used to simulate the breast. Measured mammography spectra for a molybdenum target-molybdenum filter unit were utilized. The normalized average glandular dose was calculated as a function of half-value layer, tube voltage, breast thickness, and breast composition for typical magnification geometries. RESULTS: The normalized average glandular dose in magnification mammography is 7%-25% lower than that with the contact (nonmagnification) technique because of the effects of partial irradiation, smaller field size, and greater percentage depth dose gradient at the reduced source-to-skin distance. CONCLUSION: The normalized average glandular dose in magnification mammography is lower than that in contact mammography. The average glandular dose in magnification mammography, however, is still substantially greater due to the two to three times greater entrance skin exposure.

Female↗

PubMedDate not supplied

Flow analysis with digital subtraction angiography: 2. Acquisition and accuracy of transit-flow measurements.

A steady-state flow model was used to optimize methods of data analysis, to investigate variables that affect the time-density curves, and to determine the accuracy of transit-flow measurements with digital subtraction angiography. The most accurate data were obtained by using a small region of interest placed within the vessel, averaged data acquisition, and a gamma-variate fit applied to the time-density curve. The integrated area of the curve depended on the flow, vessel size, amount of iodine injected, framing rate, and the kVp. The integrated area was not affected by the mAs; the matrix size; or the volume, concentration, or rate of injection of the contrast material. Subject density, image intensifier mode, and field size did not affect the curves except for their contribution to scatter and beam hardening. There was good correlation between digital subtraction angiographic transit-flow measurements and known flow values.

Angiography↗