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Biomedical subjects

D F Adams

Publications and source records attributed to D F Adams.

At least 181 records · Page 10Linked to original sources
PubMedDate not supplied

Silicone-fat differentiation in the breast: exploiting the bright-fat phenomenon in fast spin-echo MR imaging.

Selective suppression of silicone or fat with chemical shift-selective (CHESS) pulses is difficult because of the small chemical shift difference between the primary lipid signal and the primary silicone signal at 1.5 T. Differentiation of these chemically distinct species is, however, an important clinical task in assessing implant rupture and silicone migration in breast tissue. A method uniquely suited for silicone-fat differentiation with fast spin-echo (FSE) sequences is reported. It is based on the dependence of fat signal on echo spacing in FSE imaging and results show that it may provide a clinically robust method for silicone-fat differentiation in magnetic resonance imaging of the breast.

Adipose Tissue↗
PubMedDate not supplied

Superparamagnetic iron oxide hepatic MR imaging: efficacy and safety using conventional and fast spin-echo pulse sequences.

The purpose of this study was to evaluate the technical efficacy and safety of iv ferumoxides (Feridex), a superparamagnetic iron oxide contrast agent for detection of hepatic lesions using conventional spin-echo and fast spin-echo MR images. Precontrast and postcontrast MR studies were performed on 25 patients with suspected focal hepatic lesions. Conventional T1- and T2-weighted MR images, as well as fast spin-echo and fat suppressed fast spin-echo MR images, were evaluated. Quantitative assessment of the contrast agent was performed obtaining region of interest measurements of the liver, spleen, and selected hepatic lesions. The pulse sequences were also evaluated subjectively for overall image quality and a subjective assessment of lesion detection. The use of a superparamagnetic iron oxide contrast agent led to a decrease in hepatic signal intensity on all pulse sequences. Lesion-to-liver contrast increased 41.1%, 36.5%, and 32.0% on the conventional T2, fast spin-echo, and fat suppressed fast spin echo pulse sequences, respectively. Lesion-to-liver contrast decreased on the T1-weighted postcontrast pulse sequence by 23.8%. Despite improvement in lesion-to-liver contrast, radiologists subjectively preferred the precontrast sequences because of overall better image quality. At a dose of 10 mumol/kg, ferumoxides favorably impacts lesion-to-liver contrast, and may be useful in hepatic imaging, more with conventional T2-weighted spin-echo pulse sequences than with T2-weighted fast spin-echo pulse sequence.

Chi-Square Distribution↗
PubMedDate not supplied

MR hysterography using axial long TR imaging with three-dimensional projections of the uterus.

A rapid screening technique for the presentation of uterine cavity anatomy obtained with MR is described. MR hysterographic (MRHG) images were generated and evaluated for uterine cavity abnormalities. Six patients referred for MRI evaluation of the uterus for infertility had an MRI using a pelvic phased array coil with axial 3 mm interleaved fast spin echo images (TR 9000 ms, TE 288 ms with fat saturation) processed using maximum intensity projection algorithms to construct MRHG images. Using the conventional MR sequence as the gold standard the MRHG images were evaluated by two reviewers and accuracy calculated. MRHG took less than 3 min, demonstrated the correct diagnosis in all with a quality score of diagnostic to optimal, and with excellent interobserver agreement (kappa 0.9).

Adult↗