Scintimammographic analysis of nonpalpable breast lesions previously identified by conventional mammography.

BACKGROUND: In randomized trials, screening mammography has led to decreased mortality from breast cancer. However, the low positive predictive value of mammography (i.e., the proportion of patients with a positive test result who actually have breast cancer) results in a large number of unnecessary biopsies. We determined whether scintimammography with technetium-99m-sestamibi is a useful supplemental diagnostic tool for women with nonpalpable breast abnormalities identified by conventional mammography. METHODS: Scintimammography was performed preoperatively on 70 women who were 31-66 years of age (mean age and median age = 51 years). These women had nonpalpable breast abnormalities identified by conventional mammography; subsequently, a needle-localization excisional biopsy of each suspicious lesion was performed. Scintimammographic images were interpreted independently by two nuclear medicine physicians who were blinded to all clinical and pathologic data, and an interobserver variation analysis was performed. RESULTS: Interobserver variation analysis of the scintimammographic findings showed an agreement for breast diagnosis of 97% and a kappa coefficient of 0.90. Comparison of scintimammographic findings and histopathologic results revealed that the sensitivity (proportion of patients with breast cancer who had a positive test result), the specificity (proportion of patients without breast cancer who had a negative test result), the positive predictive value and the negative predictive value (proportion of patients with a negative test result who actually did not have breast cancer) of scintimammography were 56% (95% confidence interval [CI] = 23%-85%), 87% (95% CI = 75%-94%), 38% (95% CI = 15%-68%), and 93% (95% CI = 82%-98%), respectively. Four of nine breast cancers were not detected by scintimammography. CONCLUSION: Because of excellent interobserver agreement, scintimammography provides an objective way of detecting primary breast carcinoma. In view of its low sensitivity and positive predictive value, however, scintimammography is not currently recommended as a screening test in patients with nonpalpable positive mammographic findings.

Immunohistologic assessment of technetium-99m-MIBI uptake in benign and malignant breast lesions.

UNLABELLED: This study was undertaken to assess the relationship between the degree of 99mTc-MIBI uptake in breast lesions and the following histologic factors: neovascularity, desmoplastic reaction, cellular proliferation and mitochondrial density. METHODS: Forty-two patients who previously underwent MIBI breast imaging (4 false-negative, 12 false-positive, 15 true-negative, 11 true-positive) were studied. Immunohistochemical staining was performed for neovascularity (Factor VIII antigen), desmoplasia (alpha-actin antigen), mitochondrial density (mitochondrial antigen) and cellular proliferation (MIB-1 antigen). The degree of microscopic staining was correlated with region of interest measurements of MIBI uptake on scintigraphy. RESULTS: There was a poor correlation between MIBI uptake and the degrees of neovascularity (r = 0.08, p > 0.05) and intracellular mitochondrial density (r = 0.04, p > 0.05) while there was a moderate correlation with cellular proliferation (r = 0.4, p < 0.05) and desmoplasia (r = 0.55, p < 0.001). CONCLUSION: The degree of MIBI uptake in breast lesions is multifactorial, but it appears to be related more to the degree of desmoplastic activity and cellular proliferation than neovascularity and mitochondrial density.

Scintimammography: the new role of technetium-99m Sestamibi imaging for the diagnosis of breast carcinoma.

Technetium-99-Sestamibi scintimammography has emerged as a new procedure for the imaging of breast tumors. Currently, a large clinical experience has been developed and the results published. At the present time, the major drawback of this procedure appears to be its low sensitivity for the detection of breast carcinomas smaller than 1 cm in diameter. There are other biologic and technical issues that remain to be overcome to optimally image the breasts. Some of these include: development of a dedicated breast imager using nuclear medicine techniques, development of stereotactic needle localization of the abnormalities that demonstrate focal increase uptake in women with normal mammogram and breast physical examination, manufacturing of a breast compression device so that we can immobilize the breast in place for more adequate imaging, overcoming the issue of unilateral or bilateral diffuse breast uptake that is noted in 7-10 percent of the cases and finally, determination of optimal dose and imaging factors. This review includes our experience at Harbor-University of California, Los Angeles Medical Center with the use of this agent for breast imaging since 1992.

Scintimammography with Tc-99m sestamibi.

Mammography and physical breast examination are currently the most frequently and recognized screening tools for detection of breast carcinoma. These methods have been proved successful for early detection of breast cancer. Considering the 85% sensitivity associated with combined mammography and physical examination and a low positive predictive value of 20%-30% for diagnosis of breast carcinoma, there is a critical need for a more accurate, noninvasive imaging test to improve the sensitivity and specificity of mammography (7, 19, 20). Since early 1992, we have studied over 1200 women with clinically and/or mammographic abnormalities prior to breast biopsy and/or fine needle aspiration cytology of the breast. We have evaluated the role of Tc 99m Sestamibi as a complimentary procedure to conventional mammography in detection of breast carcinoma. The preliminary results of our studies have been published elsewhere (14, 17, 18). DuPont Merck Pharmaceutical Company in the USA on that basis, determined to conduct a multicenter clinical trial for the role of this radiopharmaceutical for the diagnosis of breast carcinoma in women with mammographically and/or clinically palpable abnormalities. This study was conducted at 42 institutions throughout the United States and Canada enrolling 673 women who where otherwise scheduled for breast biopsy and/or mastectomy. The preliminary results of this trial in both palpable and nonpalpable breast abnormalities are encouraging (24). Our most recent study on 157 women (mean age 47.9 years +/- 10.2) with 164 lesions with indications for histologic and cytologic analysis who underwent scintimammography with Tc 99m Sestamibi demonstrated the sensitivity of 92.3% and the specificity 87.5% (15). We have concluded that Scintimammography with Tc 99m Sestamibi can be used in conjunction with mammography to improve its specificity.

Comparison of electron beam computed tomography scanning and magnetic resonance imaging quantification of right ventricular mass: validation with autopsy weights.

RATIONALE AND OBJECTIVES: We compared, in the same human hearts, the ability of magnetic resonance (MR) imaging and electron beam computed tomography (CT) scanning to accurately quantify the free wall and septal components of right ventricular (RV) mass. METHODS: Eleven hearts extracted at autopsy were subjected to MR imaging and electron beam CT scanning in short-axis projections. Regression analyses of mass determinations obtained by manual planimetry MR imaging and electron beam CT scanning and autopsy weights were performed. RESULTS: RV free wall mass by both MR imaging (53.4 +/- 19.1 g) and electron beam CT scanning (53.9 +/- 20.4 g) correlated well with autopsy weight (57.7 +/- 20.2 g). Regression analysis showed a strong correlation for MR imaging (r = .88, slope = .88, standard error the estimate [SEE] = 7.2 g, p < .001) and electron beam CT scanning (r = .95, slope = .95, SEE = 6.6 g, p < .001). RV septal mass by MR imaging (10.8 +/- 3.5 g) and electron beam CT scanning (7.1 +/- 2.4 g) correlated less well with the autopsy weight (12.5 +/- 6.5 g). Regression analysis showed a fair correlation for MR imaging (r = .45, slope = .83, SEE = 2.05 g, p = .001) and a poor correlation for electron beam CT scanning (r = .46, slope = .17, SEE = 2.25 g, p = .57). CONCLUSION: Both MR imaging and electron beam CT scanning accurately predict RV free wall mass but have difficulty predicting the septal component. Because the septal component constitutes only a small proportion of the total RV mass, determinations of RV mass should be based solely on the free wall component.

Myocardial cysticercosis detected by ultrafast CT.

Cysticercosis can affect any organ of the body although central nervous system manifestations are the most common. Cysticercosis involving the myocardium is extremely rare and is usually diagnosed postmortem. We report a case of cysticercosis involving the myocardium diagnosed antemortem using ultrafast CT.

Tc-99m sestamibi and In-111 pentetreotide uptake in metastatic papillary thyroid carcinoma.

Approximately 25% of metastatic and recurrent differentiated (papillary and follicular) thyroid carcinoma do not concentrate 1-131 Nal. In such cases, diagnosis can be attempted with other radiopharmaceuticals. The authors present a case of recurrent papillary thyroid carcinoma that was well visualized with Tc-99m sestamibi and In-111 pentetreotide; but only poorly visualized by I-131 Nal.

Metastatic spread of cervical carcinoma to the right ventricle and pulmonary arteries: diagnosis by ultrafast computed tomography.

A case of previously undiagnosed cervical carcinoma metastatic to the right ventricular cavity and the central and peripheral pulmonary arteries is presented. The usefulness of ultrafast computed tomography in comparison with echocardiography for the evaluation of suspected metastatic diseases to the heart and pulmonary arteries is discussed.

Scintimammography: the complementary role of Tc-99m sestamibi prone breast imaging for the diagnosis of breast carcinoma.

PURPOSE: To evaluate the complementary role of technetium-99m sestamibi scintimammography in improvement of the sensitivity and specificity of mammography in detection of carcinoma of the breast. MATERIALS AND METHODS: At 5 and 60 minutes after intravenous injection of Tc-99m sestamibi, scintimammograms were obtained in 147 women (age range, 18-73 years; mean age, 47.9 years +/- 10.2 [standard deviation]) with 153 lesions that warranted breast biopsy (102 lesions) or fine-needle aspiration cytologic analysis (51 lesions). There were 113 palpable and 40 nonpalpable lesions. Lesion size on mammograms was 0.8 x 0.6 cm to 15.0 x 11.0 cm (mean, 2.82 cm +/- 1.71 x 2.39 cm +/- 1.56). RESULTS: Scintimammographic findings were true-positive in 47 biopsy-confirmed carcinomas, true-negative in 91 benign lesions, false-positive in 11 lesions with benign histopathologic findings (fibrocystic disease [n = 8] or fibroadenoma [n = 3]), and false-negative in four lesions of infiltrating ductal carcinoma. The sensitivity of scintimammography was 92.2%; specificity, 89.2%; positive predictive value, 81.0%; and negative predictive value, 95.8%. CONCLUSION: The authors conclude that scintimammography is a sensitive test that can improve the detection of breast carcinoma.

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.

Right ventricular mass measurement by electron beam computed tomography. Validation with autopsy data.

RATIONALE AND OBJECTIVES: Validation of right ventricular mass quantitation by electron beam computed tomography in humans has not been performed. The ability of electron beam computed tomography to accurately determine the septal component of the right ventricle also has not been determined. This article addresses both issues. METHODS: Twenty human adult hearts obtained at autopsy were scanned by electron beam computed tomography in a short-axis projection. Planimetry of the right ventricular free wall and septal components of each slice was performed and summed to determine right ventricular mass. These measurements were compared against comparable measurements obtained by autopsy weights of the hearts. RESULTS: Right ventricular free wall weights by electron beam computed tomography (53.9 +/- 18.4 g) correlated well (slope = .92, r = .92, standard error of the estimate = 7.4 g, P < .001) with autopsy weights (55.8 +/- 18.4 g). Right ventricular septal weights by electron beam computed tomography (6.1 +/- 2.3 g) correlated poorly (slope = .04, r = .11, standard error of the estimate = 2.4 g, P = .65) with autopsy weights (13.9 +/- 6.3 g). CONCLUSIONS: Electron beam computed tomography quantitation of right ventricular mass is accurate in humans if only the free wall and not the septal component is utilized.