Breast cancer is one of the most common malignancies of women, with approximately 200,000 new cases diagnosed every year in the U.S. Some breast cancers are identified by physical examination (either self-examination or an examination performed by a physician). Population-wide screening programs that use x-ray mammography to examine asymptomatic women for early signs of breast cancer are also in common use. If a suspicious area is seen on x-ray mammography, women are usually recalled for further examination. The results of these examinations are used to make decisions about further management: return to normal screening/return for short-interval followup/refer for biopsy. In current standard practice the examinations conducted after recall usually consist of diagnostic mammography and possibly ultrasound. More and more often women are being sent for additional imaging during recall workup. Extensive diagnostic ultrasound examinations and MRI are currently the most commonly chosen additional imaging added to the workup, but other imaging technologies are offered by some practitioners. It is important to triage recalled women into the correct management pathway. Women with readily treatable early-stage cancers who get mistakenly triaged into "return to normal screening" may experience a significant delay in diagnosis and treatment of the cancer. However, the majority of women who are recalled for further assessment after a screening mammography do not have cancer, and significant numbers of healthy women are referred for biopsy or short-interval followup after recall and diagnostic mammography. A number of noninvasive imaging technologies have been developed and proposed to be useful as part of the workup after recall. This evidence review focuses on additional noninvasive imaging studies that can be conducted (in addition to standard workup) after discovery of a possible abnormality on screening mammography or physical examination. These studies are intended to guide patient management decisions. In other words, these imaging studies are not intended to provide a final diagnosis as to the nature of the breast lesion; rather, they are intended to provide additional information about the nature of the lesions such that women can be more appropriately triaged into the correct management pathway. It is important to evaluate the evidence to see if women do or do not benefit from the addition of these imaging modalities to the standard workup after recall on breast cancer screening. This systematic review was commissioned by the Agency for Healthcare Research and Quality (AHRQ) to address the following Key Questions: Key Question 1. What is the accuracy (expressed as sensitivity, specificity, predictive values, and likelihood ratios) of noninvasive tests for diagnosis of breast cancer in women referred for further evaluation after identification of a possible breast abnormality on routine screening (mammography and/or clinical or self-detection of a palpable lesion)? The noninvasive tests to be evaluated are: Ultrasound (conventional B-mode, color Doppler, power Doppler, tissue harmonics, and tomography), Magnetic resonance imaging (MRI) with breast-specific coils and gadolinium-based contrast agents, with or without computer-aided diagnosis (CADx), Positron emission tomography (PET) with 18-fluorodeoxyglucose (FDG) as the tracer, with or without concurrent computed tomography (CT) scans 8, Scintimammography (SMM) with technetium-99m sestamibi (MIBI) as the tracer, including Breast Specific Gamma Imaging (BSGI). Key Question 2. Are there demographic (e.g., age) and clinical risk factors (e.g., morphologic characteristics of the lesion) that affect the accuracy of the tests considered in Key Question 1? Key Question 3. Are there other factors and considerations (e.g., safety, care setting, patient preferences, ease of access to care) that may affect the accuracy or acceptability of the tests considered in Key Questions 1 and 2?