Devkumar Mustafi PhD, Presenter: Nothing to Disclose

Marta A. Zamora BS, Abstract Co-Author: Nothing to Disclose

Sophie-Charlotte Gleber, Abstract Co-Author: Nothing to Disclose

Stefan Vogt PhD, Abstract Co-Author: Nothing to Disclose

Gregory Stanislaus Karczmar PhD, Abstract Co-Author: Nothing to Disclose

Aytekin Oto MD, Abstract Co-Author: Research Grant, Koninklijke Philips NV Consultant, Guerbet SA

Dynamic contrast enhanced MRI (DCEMRI) has become a standard component of multi-parametric prostate MRI protocols and its use is incorporated into current guidelines for prostate MRI. Analysis of DCEMRI data from prostate is usually based on distribution of gadolinium (Gd) into two well-mixed compartments (the Toft model) and assumes that Gd does not enter into the glandular lumen. However, this assumption has not been directly tested. The purpose of our study was to measure the concentration of Gd in the glandular lumen of the normal mouse prostate following I.V. injection, using X-ray fluorescence microscopy (XFM) imaging in situ.

Six C57Bl6 male mice (28-weeks old) were sacrificed 10 minutes after Gd injection I.V. (a dose of 0.13 mmol/kg) and two mice were sacrificed after saline injection. Prostate tissue samples (ventral and anterior) from each mouse were harvested and frozen; 7-μm thick slices were sectioned for XFM; and adjacent 5-μm thick slices were sectioned for H&E staining. XFM images with in-plane resolution of 0.5-1 µm were acquired using an X-ray microprobe at the Argonne National Laboratory. Concentrations of metal ions and other elements were determined.

Baseline concentration of Gd of 0.002±0.0007 mM was determined from measurements of prostatic tissue samples when no Gd was added and was used to determine the measurement error. This 'background' value was subtracted from the measured Gd concentrations in areas of normal prostatic epithelium and lumen when Gd was added. In 32 prostatic glands in 6 mice, average Gd concentrations in regions of normal epithelium and lumen were 0.27±0.07 mM and 0.18±0.09 mM, respectively.

Our data suggest that intravenously administered Gd enters into the glandular lumen in the normal mouse prostate. Moreover, we were able to quantitatively determine Gd distributions in mouse prostatic epithelium and lumen in situ. The results suggest that the conventional two compartment model should be modified to take the glandular lumen into account. Future work will investigate the kinetics of uptake and washout from the prostatic lumen and compare the kinetics in normal lumens and cancer-containing lumens.

The validation of these findings in human prostate is very critical since this may have a significant impact on quantitative analysis and interpretation of DCEMRI for diagnosis of prostate cancer.

Mustafi, D, Zamora, M, Gleber, S, Vogt, S, Karczmar, G, Oto, A, Does Intravenously Administered Gadolinium Enter into the Glandular Lumen of the Prostate: X-ray Fluorescence Microscopy Imaging of a Mouse Model.  Radiological Society of North America 2014 Scientific Assembly and Annual Meeting, - ,Chicago IL. http://archive.rsna.org/2014/14004989.html