Effects of partial volume and phase shift between fat and water in gradient-echo magnetic resonance-mammography.
The signal modulations caused by partial volume effect and phase shift between fat and water signal in gradient-echo magnetic resonance mammography (GRE MR-mammography) have been calculated. Based on this, the theoretical sensitivity and specificity of GRE MR-mammography has been investigated considering different evaluation methods for the gadolinium-diethylenetriamine penta-acetic acid (Gd-DTPA)-based signal enhancement. The results show that both in- and out-of-phase sequences suffer from partial volume effects in voxels that contain both fat and water. This can decrease sensitivity to Gd-DTPA uptake in small, fat-embedded lesions or in pathology that contains fat interspersed histologically. Additionally, out-of-phase sequences can suffer from phase cancellation effects that can further decrease their sensitivity to Gd-DTPA uptake. In the worst case signal can actually decrease during Gd-DTPA influx. Determination of enhancement relative to the baseline value can decrease the specificity of GRE MR-mammography in the out-of-phase condition and decrease the sensitivity in the in-phase condition. These effects are less pronounced when enhancement is calculated relative to fat. These effects need to be understood since Gd-DTPA uptake is the prime indicator of malignancy in MR-mammography.
Peller
M
M
Department of Diagnostic Radiology, Ludwig Maximilian University, Klinikum Grosshadern, Munchen, Germany.
Stehling
M K
MK
Sittek
H
H
Kessler
M
M
Reiser
M
M
D001940:Breast / Q000033:anatomy & histology* / Q000378:metabolism; D001943:Breast Neoplasms / Q000175:diagnosis / Q000378:metabolism; D005069:Evaluation Studies as Topic; D005223:Fats / Q000032:analysis*; D005260:Female; D019786:Gadolinium DTPA; D006801:Humans; D008055:Lipids / Q000032:analysis; D008279:Magnetic Resonance Imaging / Q000379:methods*; D008327:Mammography / Q000379:methods*; D009942:Organometallic Compounds / Q000493:pharmacokinetics; D004369:Pentetic Acid / Q000031:analogs & derivatives / Q000493:pharmacokinetics; D011522:Protons; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D014867:Water / Q000032:analysis*
D005223:Fats; D008055:Lipids; D009942:Organometallic Compounds; D011522:Protons; D014867:Water; D004369:Pentetic Acid; D019786:Gadolinium DTPA