Linda Diggles

Review of imaging techniques for the diagnosis of breast cancer: a new role of prone scintimammography using technetium-99m sestamibi.

Imaging techniques currently used for the diagnosis of breast cancer are reviewed and compared. Besides mammography, magnetic resonance imaging, positron emission tomography, and thallium-201 scintimammography, a new role of technetium-99m sestamibi scintimammography is discussed. It is concluded that while mammography remains the procedure of choice in screening asymptomatic women for breast cancer, other imaging methods play an important role in detecting malignancies in symptomatic patients.99mTc-sestamibi scintimammography has high sensitivity and improves the specificity of conventional mammography for the detection of breast cancer; with this technique, prone imaging is preferable to supine imaging.99mTc-sestamibi scintimammography thus deserves further study as a screening technique.

Tc-99m Sestamibi Scintimammography for the Evaluation of Breast Masses in Patients with Radiographically Dense Breasts.

Abstract: The objective of this study was to evaluate the usefulness of technetium‐99m sestamibi (MIBI) scintimammography for the diagnosis of breast cancer in patients with palpable breast masses that cannot be adequately evaluated by mammography due to the presence of radiographically dense breasts. At 5 minutes after intravenous injection of MIBI, scintimammograms were obtained in 80 patients who had grade 3 or 4 glandular density on mammograms and a palpable breast mass. Excisional biopsy or FNA biopsy was obtained in 68 lesions in 67 patients. Scintimammography (22 true positive, 4 false positive, 41 true negative, 1 false negative) resulted in a sensitivity of 95.6%, specificity 91.1%, positive predictive value 84.6%, and negative predictive value 97.6%. Mammography (19 true positive, 21 false positive, 24 true negative, 4 false negative) resulted in a sensitivity of 73.9%, specificity 53.3%, positive predictive value 44.7%, and negative predictive value 80%. MIBI scintimammography has a higher sensitivity and specificity than mammography in patients with radiographically dense breasts. It is useful as an adjunct to mammography in those patients with radiographically dense breasts for the characterization of palpable masses. Although sensitivity of mammography in this cohort was high, its specificity was significantly lower than scintimammography. If validated in prospective studies it could provide a safe way of avoiding a breast biopsy in patients with benign findings on clinical exam, mammography, and needle aspiration cytology.

Investigation of abnormal appearing thyroid glands on Tc-99m sestamibi breast scintimammography.

Of 507 breast scintimammograms performed using Tc-99m sestamibi, 34 patients were incidentally found to have abnormal appearing thyroid glands. The authors sought to investigate the clinical significance and/or ascertain an extraneous causative factor for these findings. One cold thyroid nodule was detected and was proven benign through biopsy. Two cases of subacute and chronic thyroiditis were proven, and it is possible that additional patients had this disease process. Focal areas of increased thyroid Tc-99m sestamibi uptake were observed in eight patients and probably represent parathyroid adenomas, nonautonomous hyperfunctioning thyroid nodules, or nontoxic multinodular goiter. The results did not yield an extraneous causative factor, underlying pathology, or clinically significant disease in all of the patients investigated, but the findings suggest a need for careful evaluation of any unusual uptake in the thyroid gland and the rest of the image. The authors do not recommend investigation of all abnormal appearing thyroid glands on Tc-99m sestamibi scintimammography. However, clinical correlation should be recommended.