Does higher gadolinium concentration play a role in the morphologic assessment of brain tumors? Results of a multicenter intraindividual crossover comparison of gadobutrol versus gadobenate dimeglumine (the MERIT Study).

BACKGROUND AND PURPOSE: Gadobenate dimeglumine has proved advantageous compared with other gadolinium-based contrast agents for contrast-enhanced brain MR imaging. Gadobutrol is a more highly concentrated agent (1.0 mol/L). This study intraindividually compared 0.1-mmol/kg doses of these agents for qualitative and quantitative evaluation of brain tumors. MATERIALS AND METHODS: Adult patients with suspected or known brain tumors underwent 2 identical MR imaging examinations at 1.5T, 1 with gadobenate dimeglumine and the other with gadobutrol, both at a dose of 0.1-mmol/kg body weight. The agents were injected in randomized order separated by 3-14 days. Imaging sequences and acquisition timing were identical for the 2 examinations. Three blinded readers evaluated images qualitatively for diagnostic information (lesion extent, delineation, morphology, enhancement, global preference) and quantitatively for CNR and LBR. RESULTS: One hundred fourteen of 123 enrolled patients successfully underwent both examinations. Final diagnoses were intra-axial tumors, metastases, extra-axial tumors, "other" tumors, and "nontumor" (49, 46, 8, 7, and 4 subjects, respectively). Readers 1, 2, and 3 demonstrated preference for gadobenate dimeglumine in 46 (40.7%), 54 (47.4%), and 49 (43.0%) patients, respectively, compared with 6, 7, and 7 patients for gadobutrol (P < .0001, all readers). Highly significant (P < .0001, all readers) preference for gadobenate dimeglumine was demonstrated for all other qualitative end points. Inter-reader agreement was good for all evaluations (κ = 0.414-0.629). Significantly superior CNR and LBR were determined for gadobenate dimeglumine (P < .019, all readers). CONCLUSIONS: Significantly greater morphologic information and lesion enhancement are achieved on brain MR imaging with 0.1-mmol/kg gadobenate dimeglumine compared with gadobutrol at an equivalent dose.

Hamartoma of the breast, an underrecognized breast lesion. A clinicopathologic and radiographic study of 25 cases.

This study investigated the clinical, radiographic, and pathologic features of breast hamartoma. The patients ranged in age from 18 to 89 years, with a mean age of 45 years, and a median age of 43 years. Seventy-five percent of the patients were asymptomatic, other than reporting a breast lump. In two patients, the lesions recurred at 7 and 18 months after the initial resection. The clinical diagnoses were fibroadenoma in 10 cases, carcinoma in 5 cases, hamartoma in 4 cases, and phyllodes tumor and lipoma in 2 other cases. Mammograms were available in 12 cases, the majority of which showed a well-defined mass of homogeneous density. Grossly, these lesions were oval to round, well-circumscribed masses, ranging in size from 1 to 7 cm in maximum dimension (mean, 3.9 cm). The microscopic appearance of these tumors corresponded to their gross appearance. Lesions that were grossly firm, rubbery, and white consisted largely of dense fibroconnective tissue with variable amounts of glandular elements with little adipose tissue. Softer, pale, yellow lesions contained more adipose tissue. A consistent and important diagnostic feature was the presence of both lobules and ducts, in contrast to fibroadenoma in which lobules are often absent or rare. The current trend of mammographic breast screening has made us aware that mammary hamartomas are not uncommon. These lesions may go unrecognized by the pathologists because they show all the constituents of normal breast tissue and may be reported as "no pathological diagnosis" or "normal breast tissue," which are inappropriate diagnoses for a lesion that presents as a palpable and a well-circumscribed mass.