Scintimammography with 99mTc-MIBI and magnetic resonance imaging in the evaluation of breast cancer

Applications of Computational Methods in Biomedical Breast Cancer Imaging Diagnostics: A Review

With the exponential increase in new cases coupled with an increased mortality rate, cancer has ranked as the second most prevalent cause of death in the world. Early detection is paramount for suitable diagnosis and effective treatment of different kinds of cancers, but this is limited to the accuracy and sensitivity of available diagnostic imaging methods. Breast cancer is the most widely diagnosed cancer among women across the globe with a high percentage of total cancer deaths requiring an intensive, accurate, and sensitive imaging approach. Indeed, it is treatable when detected at an early stage. Hence, the use of state of the art computational approaches has been proposed as a potential alternative approach for the design and development of novel diagnostic imaging methods for breast cancer. Thus, this review provides a concise overview of past and present conventional diagnostics approaches in breast cancer detection. Further, we gave an account of several computational models (machine learning, deep learning, and robotics), which have been developed and can serve as alternative techniques for breast cancer diagnostics imaging. This review will be helpful to academia, medical practitioners, and others for further study in this area to improve the biomedical breast cancer imaging diagnosis.

Scintimammography for the detection of breast cancer

Scintimammography is a functional imaging technique whereby radionuclide tracers in the patient's breasts are observed with a radiation-detection camera (gamma-camera). Tracers are designed to accumulate in tumors more than in healthy tissue; the most common tracers used to date are Tc-99m sestamibi and Tc-99m tetrofosmin. Scintimammography is useful in some clinical indications as an adjunct to mammography and to reduce the rates of negative biopsies, and it is recommended for lesions where additional information is required to reach a definitive diagnosis. Patients with equivocal mammograms may benefit from this test, as well as women with dense breasts and those with implants, since scintigraphy is not affected by breast density and the photons arising from the radiotracer are not overly attenuated by implants. Scintimammography is also of value in patients with locally advanced breast cancer, for monitoring and predicting the response to neoadjuvant chemotherapy. The near availability of high-resolution breast-dedicated cameras will allow the suboptimal sensitivity in detecting cancers of less than 1 cm to be improved; this is currently the main limitation of scintimammography. These new devices also have the potential to increase the number of breast scintigraphies performed and the role of nuclear medicine in breast cancer imaging.

Tc-99m sestamibi scintimammography for the diagnosis of breast cancer: meta-analysis and meta-regression

Tc-99m sestamibi (MIBI) is a relatively noninvasive diagnostic modality in the evaluation of breast cancer. The purpose of this study was to review the existing literature on the accuracy of Tc-99m MIBI in the diagnosis of breast cancer. After a systematic review of English-language studies, the sensitivity, specificity, and other measures of accuracy of Tc-99m MIBI in the diagnosis of breast cancer were pooled using random-effects models. Summary receiver operating characteristic curves were used to summarize the overall test performance. Forty-five studies met our inclusion criteria. The summary estimates for Tc-99m MIBI in the diagnosis of breast cancer in the studies included were as follows: sensitivity, 0.83 [95% confidence interval (CI), 0.82-0.84]; specificity, 0.85 (95% CI, 0.83-0.86); positive likelihood ratio, 5.06 (95% CI, 4.26-6.01); negative likelihood ratio, 0.20 (95% CI, 0.17-0.24); and diagnostic odds ratio, 27.63 (95% CI, 21.63-36.10). For patients with a palpable mass, the sensitivity and specificity were 87 and 86%, respectively. For patients without a palpable mass, the sensitivity and specificity were 59 and 89%, respectively. Tc-99m MIBI has a high level of overall accuracy for the diagnosis of breast cancer.

Accuracy of magnetic resonance in suspicious breast lesions: a systematic quantitative review and meta-analysis

Dynamic contrast-enhanced breast magnetic resonance (MR) is a promising emerging technique for evaluating breast lesions. A quantitative systematic review was performed to estimate the accuracy of breast MR in the diagnosis of high-risk breast lesions and breast cancer. A comprehensive search of the Cochrane Library, MEDLINE, CANCERLIT, LILACS, and EMBASE databases was performed from January 1985 to August 2010. The medical subjects heading (MeSH) and text words for the terms "breast neoplasm", "breast lesions", "breast cancer" and "magnetic resonance" were combined with the MeSH term diagnosis ("sensitivity and specificity"). Studies that compared breast MR with paraffin-embedded sections parameters for the diagnosis of breast lesions (benign, high-risk borderline, and breast cancer) were included. Sixty-nine studies were analyzed, which included 9,298 women with 9,884 breast lesions. Interrater overall agreement between breast MR and paraffin section diagnosis was 79% (κ = 0.55), indicating moderate agreement. Pooled sensitivity and specificity were 90% [95% CI 88-92%] and 75% [95% CI 70-79%], respectively. The pooled likelihood positive ratio was 3.64 (95% CI 3.0-4.2) and the negative ratio was 0.12 (95% CI 0.09-0.15). For breast cancer or high-risk lesions versus benign lesions, the AUC was 0.91 for breast MR and the point Q* was 0.84. In summary, breast MR is a useful pre-operative test for predicting the diagnosis of breast lesions.

An X-Ray computed tomography/positron emission tomography system designed specifically for breast imaging

Mammography has served the population of women who are at-risk for breast cancer well over the past 30 years. While mammography has undergone a number of changes as digital detector technology has advanced, other modalities such as computed tomography have experienced technological sophistication over this same time frame as well. The advent of large field of view flat panel detector systems enable the development of breast CT and several other niche CT applications, which rely on cone beam geometry. The breast, it turns out, is well suited to cone beam CT imaging because the lack of bones reduces artifacts, and the natural tapering of the breast anteriorly reduces the x-ray path lengths through the breast at large cone angle, reducing cone beam artifacts as well. We are in the process of designing a third prototype system which will enable the use of breast CT for image guided interventional procedures. This system will have several copies fabricated so that several breast CT scanners can be used in a multi-institutional clinical trial to better understand the role that this technology can bring to breast imaging.

Meta-analysis of MR imaging in the diagnosis of breast lesions

PURPOSE

To determine, in a meta-analysis, the diagnostic performance of contrast material-enhanced magnetic resonance (MR) imaging in patients with breast lesions.

MATERIALS AND METHODS

Studies to assess the diagnostic performance of MR imaging in patients suspected of having breast cancer who underwent MR imaging and biopsy from January 1985 through March 2005 were reviewed for inclusion. A summary receiver operating characteristic curve was constructed, and pooled weighted estimates of sensitivity and specificity were calculated by using the recently developed bivariate approach for diagnostic meta-analysis.

RESULTS

Of 251 eligible studies, 44 were included in the meta-analysis (sample size range, 14-821; cancer prevalence, 23%-84%). Pooled weighted estimates of sensitivity and specificity were 0.90 (95% confidence interval: 0.88, 0.92) and 0.72 (95% confidence interval: 0.67, 0.77), respectively. The performance of breast MR imaging was influenced by the prevalence of cancer in the studied population (P = .05) and by whether two criteria (ie, morphology, enhancement, and kinetic enhancement pattern)--versus one or three criteria--were used to differentiate benign from malignant lesions (P = .02).

CONCLUSION

MR imaging of the breast has high sensitivity and lower specificity in the evaluation of breast lesions.

SUPPLEMENTAL MATERIAL

http://radiology.rsnajnls.org/cgi/content/full/2461061298/DC1.

Breast-specific gamma imaging with 99mTc-Sestamibi and magnetic resonance imaging in the diagnosis of breast cancer--a comparative study

The purpose of this study was to compare the sensitivity and specificity of breast-specific gamma imaging (BSGI) using a high-resolution breast-specific gamma camera and magnetic resonance imaging (MRI) in patients with indeterminate breast findings. Twenty-three women with an indeterminate breast finding that required BSGI and MRI as deemed necessary by the interpreting radiologist or referring physician were included. MRI was performed on a GE 1.5T scanner and BSGI was performed on a Dilon high-resolution breast-specific gamma camera. All imaging findings were correlated with pathologic diagnosis. Thirty-three indeterminate lesions were evaluated in the study. There were a total of nine pathologically confirmed cancers. There was no statistically significant difference in sensitivity of cancer detection between BSGI and MRI. BSGI demonstrated a greater specificity than MRI, 71% and 25%, respectively. BSGI has equal sensitivity and greater specificity than MRI for the detection of breast cancer.

99MTechnetium-sestamibi scintimammography in non-palpable breast lesions found on screening X-ray mammography

OBJECTIVE

The sensitivity and specificity of (99m)Tc-sestamibi scintimammography in patients with non-palpable breast lesions diagnosed by screening mammography and the value of (99m)Tc-sestamibi to detect axillary lymph node metastases was determined.

METHODS

Between September 2000 and December 2003, 103 females with non-palpable breast lesions were included for further evaluation. X-ray mammography was repeated and 99mTc-sestamibi scintimammography performed within one-week. Anterior, and left and right lateral images were obtained. The scintimammography was analysed by 2 experienced observers who were blinded to the clinical, pathological, and radiological results. The sensitivity and specificity of scintimammography to diagnose non-palpable lesion(s), including the axillary regions, was compared with histopathology, clinical, and radiological follow up.

RESULTS

Two patients (one non-small lung cancer and one non-Hodgkin's disease) were excluded. Both showed (99m)Tc-sestamibi avid lesions in the breast and axillary region. In the remaining 101 patients, 37 true positive (TP), 4 false positive (FP), 52 true negative (TN), and 8 false negative (FN) breast carcinomas were found. The specificity was 92.8%, sensitivity 82.2%, positive predictive value (PPV) 90.2%, and negative predictive value (NPV) 86.6%. (99m)Tc-sestamibi scintimammography showed axillary lesions in 5/15 (33%) patients with axillary lymph node metastasis.

CONCLUSION

In patients with non-palpable lesions diagnosed by screening- X-ray-mammography, (99m)Tc-sestamibi scintimammography provided high specificity and PPV. Furthermore, (99m)Tc-sestamibi scintimammography detected 33% of patients with axillary lymph node metastases. Therefore, (99m)Tc-sestamibi scintimammography could be of incremental value in the surgical work-up of these patients.

Initial evaluation of breast cancer using Tc-99m sestamibi scintimammography

AIM

Aim of the study was to elaborate on the diagnostic role of Tc-99m sestamibi scintimammography (SMM) in the initial diagnosis of breast cancer, partially in comparison to MRI. The study presents an update of previously published data.

MATERIALS AND METHODS

Out of a total of 464 scintimammograms findings of 252 studies were correlated with the histopathologic outcome. A subgroup of 68 patients with indeterminate preliminary diagnosis underwent additional MRI. SMM and MRI findings were correlated to the final hisopathological outcome.

RESULTS

Overall sensitivity and specificity for SMM were 84 and 85%, respectively. Depending on tumor size sensitivity ranged from 60% for stage pT1a,b carcinomas to 94% stage pT1c or higher. In the subgroup with indeterminate preliminary diagnosis sensitivity of SMM decreased to 76% which was lower as compared to MRI (84%). Specificity of SMM was 86% in this subgroup which was evidently higher as compared to MRI (51%).

CONCLUSION

SMM has severe limitations in the diagnosis of small carcinoma and therefore should not be used for breast cancer screening. SMM can be used to further evaluate indeterminate or probably benign mammographic findings, especially when conventional mammography is inconclusive due to dense breast tissue.