Kanae Miyake

Benign or malignant?: differentiating breast lesions with computed tomography attenuation values on dynamic computed tomography mammography.

Objective: To evaluate enhancement effects of breast lesions with dynamic computed tomography (CT) and to determine characteristics to aid in differential diagnosis of benign and malignant lesions. Methods: One hundred seventy-six women underwent preoperative dynamic CT, in which they were scanned with rapid injection of contrast media (3 mL/s) after 30 seconds and 2 minutes (early and delayed phases, respectively). The CT values and enhancement patterns of malignant lesions (n = 154) were compared with those of benign lesions (n = 22), and the cut point of CT values with the best validity was analyzed. Results: The CT values of malignant lesions were higher than those of benign lesions in both phases (P < 0.0001). The cut point was determined to be 60 Hounsfield units (HU) in the early phase (44% validity, 90% sensitivity). Washout and plateau patterns were more commonly seen in the malignant group (73% specificity). Conclusions: The analysis of enhancement effects on CT may lead to more appropriate differentiation of benign and malignant lesions.

Performance Evaluation of a New Dedicated Breast PET Scanner Using NEMA NU4-2008 Standards

The aim of this work was to evaluate the performance characteristics of a newly developed dedicated breast PET scanner, according to National Electrical Manufacturers Association (NEMA) NU 4-2008 standards. Methods: The dedicated breast PET scanner consists of 4 layers of a 32 × 32 lutetium oxyorthosilicate–based crystal array, a light guide, and a 64-channel position-sensitive photomultiplier tube. The size of a crystal element is 1.44 × 1.44 × 4.5 mm. The detector ring has a large solid angle with a 185-mm aperture and an axial coverage of 155.5 mm. The energy windows at depth of interaction for the first and second layers are 400–800 keV, and those at the third and fourth layers are 100–800 keV. A fixed timing window of 4.5 ns was used for all acquisitions. Spatial resolution, sensitivity, counting rate capabilities, and image quality were evaluated in accordance with NEMA NU 4-2008 standards. Human imaging was performed in addition to the evaluation. Results: Radial, tangential, and axial spatial resolution measured as minimal full width at half maximum approached 1.6, 1.7, and 2.0 mm, respectively, for filtered backprojection reconstruction and 0.8, 0.8, and 0.8 mm, respectively, for dynamic row-action maximum-likelihood algorithm reconstruction. The peak absolute sensitivity of the system was 11.2%. Scatter fraction at the same acquisition settings was 30.1% for the rat-sized phantom. Peak noise-equivalent counting rate and peak true rate for the ratlike phantom was 374 kcps at 25 MBq and 603 kcps at 31 MBq, respectively. In the image-quality phantom study, recovery coefficients and uniformity were 0.04–0.82 and 1.9%, respectively, for standard reconstruction mode and 0.09–0.97 and 4.5%, respectively, for enhanced-resolution mode. Human imaging provided high-contrast images with restricted background noise for standard reconstruction mode and high-resolution images for enhanced-resolution mode. Conclusion: The dedicated breast PET scanner has excellent spatial resolution and high sensitivity. The performance of the dedicated breast PET scanner is considered to be reasonable enough to support its use in breast cancer imaging.

Diagnostic value of18F-FDG PET/CT and MRI in predicting the clinicopathologic subtypes of invasive breast cancer

OBJECTIVE The purpose of this study was to assess the diagnostic value of (18)F-FDG PET/CT and MRI in predicting the clinicopathologic subtypes of breast cancer. MATERIALS AND METHODS The cases of 89 patients with mass-type invasive breast cancer who underwent FDG PET/CT and MRI before therapy were retrospectively analyzed. Eight imaging variables-maximum standardized uptake value (SUVmax), apparent diffusion coefficient, size, shape, margin, intratumoral enhancement, dynamic kinetics, and high intratumoral signal intensity on T2-weighted images-were compared with results for the pathologic markers Ki-67 antibody, estrogen receptor (ER), progesterone receptor (PR), and ERBB2 (formerly HER2 or HER2/neu). The diagnostic performance of the imaging variables for sub-typing was evaluated, and the predictors of the subtypes were elucidated. RESULTS Higher SUVmax was significantly associated with a high Ki-67 index (p < 0.0001), ER-negative status (p = 0.0001), and PR-negative status (p = 0.047). Significant correlation was also found between size and ER status (p = 0.002) and between shape and PR status (p = 0.044). The AUC exceeded 0.7 only in identification of the luminal A sub-type by application of cutoff values for SUVmax (AUC, 0.751). When smaller tumors were excluded, AUC increased (AUC, 0.803 for tumors > 16 mm). Multivariate analysis showed that SUVmax was the sole independent predictor of luminal A subtype (odds ratio per SD, 0.291; p < 0.0001). SUVmax was significantly lower for luminal A (4.4 ± 2.2) than non-luminal A (8.1 ± 4.4; p < 0.0001) tumors. A cutoff value of 5.4 yielded 79% sensitivity and 68% specificity for prediction that a tumor was the luminal A subtype. CONCLUSION FDG PET/CT findings may contribute to differentiation of the luminal A and non-luminal A subtypes of invasive breast cancer.

F-18 Fdg Pet of Foreign Body Granuloma: Pathologic Correlation With Imaging Features in 3 Cases

Purpose: Retained textiles with foreign body granulomatous reaction can form mass-mimicking soft tissue tumors, which may cause diagnostic, clinical, and medicolegal problems. In this study, we present 3 cases of foreign body granuloma by retained textiles, and demonstrate FDG PET findings with detailed pathologic correlation. We also provide a review of previous literatures. Materials and Methods: Three patients (all females; age range, 48–61 years) with histopathologic diagnosis of mass-forming foreign body granuloma caused by retained textiles were retrospectively studied. They underwent an FDG PET scan in our institute. The mass was located in the abdominopelvic cavity in all cases. The time interval between the prior surgery and the PET acquisition was 11 months, 15 or 19 years, and 26 years, respectively. Results: Intense FDG uptake with a ring-shaped pattern was observed in 2 cases, while no uptake in 1 case. Microscopically, 2 with ring-shaped FDG uptake showed a cellular foreign body reaction peripherally, and artificial textile fibers and acellular eosinophilic amorphous materials in the central portion. In the one without FDG uptake, the mass was composed of mainly necrotic debris surrounding by a thick layer of well-formed collagen fibers. In previous case reports describing the accumulation of FDG in foreign body granulomas, 9 of 10 cases showed intense FDG uptake with a ring-shaped pattern. Conclusions: The ring-shaped pattern of FDG uptake seems to well characterize pseudotumor with foreign body granulomas. However, the pattern of FDG accumulation in retained textile with foreign body granulomas may vary due to histologic features.

Patient Awareness of Breast Density and Interest in Supplemental Screening Tests: Comparison of an Academic Facility and a County Hospital

PURPOSE The aim of this study was to measure womens knowledge of breast density and their attitudes toward supplemental screening tests in the setting of the California Breast Density Notification Law at an academic facility and a county hospital, serving women with higher and lower socioeconomic status, respectively. METHODS Institutional review board exemptions were obtained. A survey was administered during screening mammography at two facilities, assessing womens awareness of and interest in knowing their breast density and interest in and willingness to pay for supplemental whole breast ultrasound and contrast-enhanced spectral mammography (CEMG). The results were compared by using Fisher exact tests between groups. RESULTS A total of 105 of 130 and 132 of 153 women responded to the survey at the academic and county facilities, respectively. Among respondents at the academic and county facilities, 23% and 5% were aware of their breast density, and 94% and 79% wanted to know their density. A majority were interested in supplemental ultrasonography and CEMG at both sites; however, fewer women had a willingness to pay for the supplemental tests at the county hospital compared with those at the academic facility (22% and 70%, respectively, for ultrasound, P < .0001; 20% and 65%, respectively, for CEMG, P < .0001). CONCLUSIONS Both groups of women were interested in knowing their breast density and in supplemental screening tests. However, women at the county hospital were less willing to incur out-of-pocket expenses, suggesting a potential for a disparity in health care access for women of lower socioeconomic status after the enactment of breast density notification legislation.

Assessment of tumor morphology on diffusion-weighted (DWI) breast MRI : Diagnostic value of reduced field of view DWI

To compare the diagnostic value of conventional, bilateral diffusion‐weighted imaging (DWI) and high‐resolution targeted DWI of known breast lesions.

Higher breast cancer conspicuity on dbPET compared to WB-PET/CT

OBJECTIVES The purpose of this study was to evaluate lesion detectability of a dedicated breast positron-emission tomography (dbPET) scanner for breast cancers with an updated reconstruction mode, comparing it to whole-body positron-emission tomography/computed tomography (WB-PET/CT). MATERIALS AND METHODS A total of 179 histologically-proven breast cancer lesions in 150 females who underwent both WB-PET/CT and dbPET with 18F-fluorodeoxyglucose were retrospectively analyzed. The patient/breast/lesion-based sensitivities based on visual analysis were compared between dbPET and WB-PET/CT. For lesions visible on both PET images, SUVmax values of the tumors were measured, and tumor-to-background ratios (T/B ratios) of SUVmax were compared between the two scans. Subgroup analyses according to clinical tumor stage, histopathology and histological grade were also performed. RESULTS Patient/breast/lesion-based sensitivities were 95%, 95%, and 92%, respectively, for dbPET, and 95%, 94%, and 88%, respectively, for WB-PET/CT. Mean±standard deviation SUVmax values of FDG-avid tumors were 13.0±9.7 on dbPET and 6.4±4.8 on WB-PET. T/B ratios were also significantly higher in dbPET than in WB-PET/CT (8.1±7.1 vs. 5.1±4.5). In the subgroup analysis, no significant differences in sensitivities between dbPET and WB-PET/CT were found. However, T/B ratios of dbPET were significantly higher than those of WB-PET/CT in cT1c, cT2, cT3, invasive cancer, invasive carcinoma of no special type, mucinous carcinoma and Grades 1-3. CONCLUSION No significant differences in sensitivities were identified between dbPET using an updated reconstruction mode and WB-PET/CT; however, T/B ratios of dbPET were significantly higher than those of WB-PET/CT, indicating higher tumor conspicuity on dbPET.

Clinical, Morphologic, and Pathologic Features Associated With Increased FDG Uptake in Schwannoma

OBJECTIVE The objective of this study was to investigate the clinical, morphologic, and pathologic features associated with increased 18F-FDG uptake in benign schwannomas. MATERIALS AND METHODS Twenty-two schwannomas in 22 patients (age range, 25-81 years) who had FDG PET or PET/CT scans and subsequently underwent surgical re-section were retrospectively analyzed. The maximum standardized uptake value (SUVmax) was compared with patient age, sex, tumor location (gastrointestinal vs nongastrointestinal origin), tumor size, gross appearance, intratumoral cellularity, intratumoral infiltration of inflammatory cells, presence of peritumoral lymphoid cuffs, and expression status of glucose transporters 1 and 3 on tumor cells. RESULTS The SUVmax of schwannomas ranged from 1.5 to 17.3 (median, 3.7). Significantly higher SUVmax was observed in gastrointestinal schwannomas (n = 4) compared with nongastrointestinal schwannomas (n = 18, p = 0.007) and in schwannomas with peritumoral lymphoid cuffs (n = 5) compared with those without peritumoral lymphoid cuffs (n = 17, p = 0.001). A significant correlation was seen between tumor location and the presence of peritumoral lymphoid cuffs (p < 0.001). Age, sex, tumor size, gross appearance, intratumoral cellularity, intratumoral inflammatory cell infiltration, and expression status of glucose transporters 1 and 3 on tumor cells had no significant correlation with SUVmax. CONCLUSION Gastrointestinal schwannomas and schwannomas with peritumoral lymphoid cuffs may be associated with elevated FDG uptake. Knowledge of the features of schwannomas associated with increased uptake may be helpful to avoid misinterpretation of benign schwannomas as malignancy.

CT‐Guided Wire Localization for Involved Axillary Lymph Nodes After Neo‐adjuvant Chemotherapy in Patients With Initially Node‐Positive Breast Cancer

Resection of biopsy‐proven involved axillary lymph nodes (iALNs) is important to reduce the false‐negative rates of sentinel lymph node (SLN) biopsy after neo‐adjuvant chemotherapy (NAC) in patients with initially node‐positive breast cancer. Preoperative wire localization for iALNs marked with clips placed during biopsy is a technique that may help the removal of iALNs after NAC. However, ultrasound (US)‐guided localization is often difficult because the clips cannot always be reliably visible on US. Computed tomography (CT)‐guided wire localization can be used; however, to date there have been no reports on CT‐guided wire localization for iALNs. The aim of this study was to describe a series of patients who received CT‐guided wire localization for iALN removal after NAC and to evaluate the feasibility of this technique. We retrospectively analyzed five women with initially node‐positive breast cancer (age, 41–52 years) who were scheduled for SLN biopsy after NAC and received preoperative CT‐guided wire localization for iALNs. CT visualized all the clips that were not identified on post‐NAC US. The wire tip was deployed beyond or at the target, with the shortest distance between the wire and the index clip ranging from 0 to 2.5 mm. The total procedure time was 21–38 minutes with good patient tolerance and no complications. In four of five cases, CT wire localization aided in identification and resection of iALNs that were not identified with lymphatic mapping. Residual nodal disease was confirmed in two cases: both had residual disease in wire‐localized lymph nodes in addition to SLNs. Although further studies with more cases are required, our results suggest that CT‐guided wire localization for iALNs is a feasible technique that facilitates identification and removal of the iALNs as part of SLN biopsy after NAC in situations where US localization is unsuccessful.

Current Status of Dedicated Breast PET Imaging

Positron emission tomography (PET) is a useful technique to visualize biologic processes within body. Techniques of PET imaging for breast cancer continue to evolve and have been improving the limitation of the spatial resolution of conventional whole body PET scanners. Currently, several types of dedicated breast PET system, including positron emission mammography and fully tomographic dedicated PET systems, have been developed. In this article, we review types and features of developed scanners, the results of clinical studies, and the potential future deployment of dedicated breast PET imaging. We also briefly review PET tracers that could be potential candidates for use in dedicated breast PET imaging.