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Characteristics of Dynamic Magnetic Resonance Image Enhancement in Prolactinomas Resistant to Dopamine Agonist Therapy
  1. Qinghua Guo, PhD*,
  2. Bradley J. Erickson, MD, PhD,
  3. Alice Y. Chang, MD, MSc,
  4. Dana Erickson, MD
  1. From the *Division of Endocrinology, Chinese PLA General Hospital, Beijing, China; and †Department of Radiology and ‡Division of Endocrinology, Diabetes, Metabolism, and Nutrition, Mayo Clinic, Rochester, MN.
  1. Received October 16, 2014, and in revised form November 12, 2014.
  2. Accepted for publication November 18, 2014.
  3. Reprints: Dana Erickson, MD, Division of Endocrinology, Diabetes, Metabolism, and Nutrition, Mayo Clinic, 200 First St SW, Rochester, MN. E-mail: erickson.dana{at}mayo.edu.
  4. Portions of this manuscript (Methods) have been published previously in Guo et al. Clin Endocrinol (Oxf). 2014 (published online ahead of print), used with permission.
  5. The work has been partially supported by the National Natural Science Foundation of China (project grant 81270866). A.Y.C. was supported by the Office of Women’s Health Research (Building Interdisciplinary Careers in Women’s Health award K12HD065987). The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.
  6. The authors have no conflicts of interest to declare.
  7. The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.

Abstract

Objective The objective of this study was to determine whether dynamic magnetic resonance imaging (dMRI) enhancement parameters could predict dopamine agonist (DA) resistance in prolactinomas.

Methods We retrospectively identified patients with prolactinomas who were treated with DA and underwent dMRI from 2001 through 2012 at Mayo Clinic (Rochester, MN). Intensities of the adenoma and pituitary gland were measured by drawing regions of interest on the images. Enhancement ratio, enhancement peak, prepeak slope (PPS), and enhancement time were compared between DA-resistant and DA-responsive groups, between DA-treated and DA-naive groups, and between the first and follow-up dMRIs.

Results We identified 49 patients with prolactinomas, with 6 (12.2%) showing DA resistance. Thirty-seven patients (75.5%) underwent dMRI while receiving treatment, 12 (25.5%) underwent dMRI before starting therapy, and 10 (20.4%) had follow-up dMRI after DA therapy. The PPS of the tumor was higher in the treatment-resistant group versus the responsive group (mean [SD], 4.42 [3.19] vs 2.65 [1.59]; P = 0.03), whereas no difference was noted in the pituitary gland (5.79 [2.21] vs 4.06 [2.48]; P = 0.11). Logistic regression analysis indicated that tumor PPS was associated with DA resistance (odds ratio, 1.71; 95% confidence interval, 1.07–3.27; P = 0.02).

Conclusions Dynamic MRI with PPS analysis potentially can be used early in the treatment course to evaluate DA resistance in pituitary prolactinomas.

Key Words
  • adenoma
  • magnetic resonance imaging
  • neurotransmitter agents
  • pituitary neoplasms

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