SCOUT® Localization Using MRI Guidance: Initial Experience.

OBJECTIVE: The Food and Drug Administration approved the MRI-compatible wireless SCOUT localization system in April 2022. The purpose of this study was to evaluate feasibility of SCOUT localization under MRI guidance. We present our initial experience adopting MRI-guided SCOUT localization and compare it to MRI-guided wire localization. METHODS: Electronic medical records and imaging were retrospectively reviewed for all patients who underwent MRI-guided SCOUT or wire localization at our institution between October 2022 and July 2023. Statistical analysis was performed using 2-sample proportion and Wilcoxon rank-sum tests. RESULTS: There were 14 MRI-guided SCOUT and 23 MRI-guided wire localization cases during the study period. All SCOUTs were placed without complication and were considered to be in adequate proximity to the target. There was no significant difference in complication rate (P = .25) or days lapsed from MRI-detected abnormality to surgery (P = .82) between SCOUT and wire cases. SCOUT was placed at time of biopsy for 71% (10/14) of cases. 57% (8/14) of SCOUT cases were used for breast conservation surgery (BCS) compared to 100% (23/23) of wire cases (P <.01), with all 6 SCOUTs not used for BCS placed at time of biopsy. CONCLUSION: MRI-guided SCOUT localization is feasible and offers an alternative to MRI-guided wire localization, with no SCOUT complications reported. SCOUT placement at time of biopsy obviates the need for an additional procedure, but predicting appropriateness is challenging, with 60% (6/10) of SCOUTs placed at time of MRI-guided biopsy not used for subsequent localization surgery.

SCOUT® Radar Localization at Time of Breast Biopsy.

OBJECTIVE: Evaluate surgical utilization of SCOUT reflectors placed at breast biopsy. METHODS: Consent was waived for this retrospective IRB-approved, HIPAA-compliant study. Breast biopsy examinations that reported the term "SCOUT" between January 2021 and June 2022 were identified using an institutional search engine. Cases were included if a SCOUT reflector was placed at time of breast biopsy and excluded if lesion pathology was already known. Analysis was performed at the lesion level. A multivariate-regression analysis evaluated 6 variables with potential impact on SCOUT utilization. RESULTS: One hundred twenty-one lesions in 112 patients met inclusion criteria. Biopsy yielded 93% (113/121) malignant, 3% (4/121) elevated risk, 2% (2/121) benign-discordant, and 2% (2/121) benign-concordant results. Two cases lost to follow-up were excluded. SCOUT reflectors were utilized for lumpectomy (58%, 69/119 lesions) and excisional biopsy (6%, 7/119 lesions). SCOUTs were not utilized due to mastectomy (23%, 27/119), subsequent wire localization (2%, 2/119), and nonsurgical cases (12%, 14/119). Reflector placement utilization was 52% higher for findings less than 3.5 cm in size (P <.001), 33% higher in patients without prior treated breast cancer (P = .012), and 19% higher in patients with no suspicious ipsilateral lymph node (P = .048). CONCLUSION: SCOUT reflector placement at time of biopsy was utilized for surgery 64% (76/119) of the time, although most (98%, 119/121) biopsies were malignant, elevated risk, or benign-discordant. Factors increasing reflector utilization include smaller lesion size, no suspicious ipsilateral lymph node, and no prior treated breast cancer.

Breast Hemangiomas: Imaging Features With Histopathology Correlation.

Breast hemangiomas are rare benign vascular lesions. In a previously performed review of approximately 10,000 breast surgical pathology results, roughly 0.15% (15/~10 000) were hemangiomas. Hemangiomas are more frequent in women and have a documented age distribution of 1.5 to 82 years. They are most often subcutaneous or subdermal and anterior to the anterior mammary fascia but may rarely be seen in the pectoralis muscles or chest wall. On imaging, breast hemangiomas typically present as oval or round masses, often measuring less than 2.5 cm, with circumscribed or mostly circumscribed, focally microlobulated margins, equal or high density on mammography, and variable echogenicity on US. Calcifications, including phleboliths, can be seen. Color Doppler US often shows hypovascularity or avascularity. MRI appearance can vary, although hemangiomas are generally T2 hyperintense and T1 hypointense with variable enhancement. Pathologic findings vary by subtype, which include perilobular, capillary, cavernous, and venous hemangiomas. If core biopsy pathology results are benign, without atypia, and concordant with imaging and clinical findings, surgical excision is not routinely indicated. Because of histopathologic overlap with well-differentiated or low-grade angiosarcomas, surgical excision may be necessary for definitive diagnosis. Findings that are more common with angiosarcomas include size greater than 2 cm, hypervascularity on Doppler US, irregular shape, and invasive growth pattern.

A machine learning model that classifies breast cancer pathologic complete response on MRI post-neoadjuvant chemotherapy.

BACKGROUND: For breast cancer patients undergoing neoadjuvant chemotherapy (NAC), pathologic complete response (pCR; no invasive or in situ) cannot be assessed non-invasively so all patients undergo surgery. The aim of our study was to develop and validate a radiomics classifier that classifies breast cancer pCR post-NAC on MRI prior to surgery. METHODS: This retrospective study included women treated with NAC for breast cancer from 2014 to 2016 with (1) pre- and post-NAC breast MRI and (2) post-NAC surgical pathology report assessing response. Automated radiomics analysis of pre- and post-NAC breast MRI involved image segmentation, radiomics feature extraction, feature pre-filtering, and classifier building through recursive feature elimination random forest (RFE-RF) machine learning. The RFE-RF classifier was trained with nested five-fold cross-validation using (a) radiomics only (model 1) and (b) radiomics and molecular subtype (model 2). Class imbalance was addressed using the synthetic minority oversampling technique. RESULTS: Two hundred seventy-three women with 278 invasive breast cancers were included; the training set consisted of 222 cancers (61 pCR, 161 no-pCR; mean age 51.8 years, SD 11.8), and the independent test set consisted of 56 cancers (13 pCR, 43 no-pCR; mean age 51.3 years, SD 11.8). There was no significant difference in pCR or molecular subtype between the training and test sets. Model 1 achieved a cross-validation AUROC of 0.72 (95% CI 0.64, 0.79) and a similarly accurate (P = 0.1) AUROC of 0.83 (95% CI 0.71, 0.94) in both the training and test sets. Model 2 achieved a cross-validation AUROC of 0.80 (95% CI 0.72, 0.87) and a similar (P = 0.9) AUROC of 0.78 (95% CI 0.62, 0.94) in both the training and test sets. CONCLUSIONS: This study validated a radiomics classifier combining radiomics with molecular subtypes that accurately classifies pCR on MRI post-NAC.

Differentiation between subcentimeter carcinomas and benign lesions using kinetic parameters derived from ultrafast dynamic contrast-enhanced breast MRI.

OBJECTIVES: This study aims to evaluate ultrafast DCE-MRI-derived kinetic parameters that reflect contrast agent inflow effects in differentiating between subcentimeter BI-RADS 4-5 breast carcinomas and benign lesions. METHODS: We retrospectively reviewed consecutive 3-T MRI performed from February to October 2017, during which ultrafast DCE-MRI was performed as part of a hybrid clinical protocol with conventional DCE-MRI. In total, 301 female patients with 369 biopsy-proven breast lesions were included. Ultrafast DCE-MRI was acquired continuously over approximately 60 s (temporal resolution, 2.7-7.1 s/phase) starting simultaneously with the start of contrast injection. Four ultrafast DCE-MRI-derived kinetic parameters (maximum slope [MS], contrast enhancement ratio [CER], bolus arrival time [BAT], and initial area under gadolinium contrast agent concentration [IAUGC]) and one conventional DCE-MRI-derived kinetic parameter (signal enhancement ratio [SER]) were calculated for each lesion. Wilcoxon rank sum test or Fisher's exact test was performed to compare kinetic parameters, volume, diameter, age, and BI-RADS morphological descriptors between subcentimeter carcinomas and benign lesions. Univariate/multivariate logistic regression analyses were performed to determine predictive parameters for subcentimeter carcinomas. RESULTS: In total, 125 lesions (26 carcinomas and 99 benign lesions) were identified as BI-RADS 4-5 subcentimeter lesions. Subcentimeter carcinomas demonstrated significantly larger MS and SER and shorter BAT than benign lesions (p = 0.0117, 0.0046, and 0.0102, respectively). MS, BAT, and age were determined as significantly predictive for subcentimeter carcinoma (p = 0.0208, 0.0023, and < 0.0001, respectively). CONCLUSIONS: Ultrafast DCE-MRI-derived kinetic parameters may be useful in differentiating subcentimeter BI-RADS 4 and 5 carcinomas from benign lesions. KEY POINTS: • Ultrafast DCE-MRI can generate kinetic parameters, effectively differentiating breast carcinomas from benign lesions. • Subcentimeter carcinomas demonstrated significantly larger maximum slope and shorter bolus arrival time than benign lesions. • Maximum slope and bolus arrival time contribute to better management of suspicious subcentimeter breast lesions.

Preventive Care: How Mammography Utilization Changes as Women Age.

OBJECTIVE: To evaluate the impact of comorbid conditions and age on mammography use. METHODS: We used data from the 2011 to 2015 Medical Expenditure Panel Survey, which contained records for 40,752 women over the age of 40. Use was defined as a mammogram within the previous 1 or 2 years, analyzed separately. A logit model was employed to evaluate associations between use and comorbidities and age. Statistical significance was defined by a P < .05 by two-sided test. RESULTS: Of the 36,575 women in our study sample, 45.9%, 43.6%, 3.9%, and 5.7% reported a history of hypertension (HTN), hyperlipidemia (HLD), prior heart attack (MI), and prior stroke, respectively. Among women without a comorbid condition, there was 47.3% annual mammography use. HTN and HLD were associated with increased use (2.5 and 6.8 percentage points [pp], P< .01). In comparison, prior MI was associated with decreased annual use (-8.2 pp, P < .01). Prior stroke was not significantly associated with annual mammography (-1.5 pp, P = .42). Results were similar for biennial use. The age trend in use showed that the age with maximum screening use was approximately 60 years. DISCUSSION: Mammography use was higher in patients with HTN and HLD and lower in patients with prior MI and stroke, which may reflect differences in comorbidity-related general health care use. Use increased until it peaked around age 60. An understanding of how mammography use naturally evolves as people age may help better target specific populations and improve overall use of preventive care.

Incidence of benign and malignant peri-implant fluid collections and masses on magnetic resonance imaging in women with silicone implants.

BACKGROUND: To assess the incidence of benign and malignant peri-implant fluid collections and/or masses on magnetic resonance imaging (MRI) in women with silicone implants who are being screened for silent implant rupture. METHODS: The institutional review board approved this HIPAA-compliant retrospective study and waived informed consent. Women who underwent silicone implant oncoplastic and/or cosmetic surgery and postoperative implant-protocol MRI from 2000 to 2014 were included. Peri-implant fluid collections and/or masses were measured volumetrically. A benign peri-implant fluid collection and/or mass was pathologically proven or defined as showing 2 years of imaging and/or clinical stability. A malignant peri-implant fluid collection was pathologically proven. Incidence of peri-implant fluid collections and/or masses and positive predictive value (PPV) were calculated on a per-patient level using proportions and exact 95% confidence intervals (CIs). Fisher's exact test was used in the analysis to test statistical significance pre-defined as P-value < 0.05. RESULTS: A total of 1070 women with silicone implants were included (mean age, 50.7 years; range, 40.4-53.8). Median time between reconstructive surgery and first MRI was 88.9 months (range, 0.8-1363.3). Eighteen women (1.7%) had a peri-implant fluid collection and/or mass: 15/18 (83.3%) had adequate follow-up; and only 1/15 was malignant implant associated anaplastic large cell lymphoma, with a PPV of 6.7% (95% CI: 0.003-0.0005). The median peri-implant fluid collection size was 89 mL (range, 18-450 mL). CONCLUSION: Peri-implant fluid collections and/or masses identified at silicone implant protocol breast MR imaging are rarely seen 24 months after reconstructive surgery. Image-guided fine-needle aspiration with flow cytometry may be warranted to evaluate for implant-associated lymphoma.

Rare Cancer on the Rise: An Educational Review of Breast Implant-associated Anaplastic Large Cell Lymphoma.

Breast implant-associated anaplastic large cell lymphoma (BIA-ALCL) is a rare but increasingly important diagnosis as the incidence of breast implant placement, both elective and reconstructive, continues to rise. When detected and treated early, this indolent disease carries an excellent prognosis. However, because the clinical presentation is often nonspecific, it is crucial for radiologists to accurately identify the imaging findings associated with BIA-ALCL to facilitate a timely diagnosis. This article will provide radiologists with an overview of the diagnosis, imaging findings, and management of BIA-ALCL.

Teaching Medical Students Optimal Consulting Skills: The Challenge of Generating Better Referring Physicians.

Rationale and objectives We sought to incorporate a new teaching module into the traditional medical student radiology clerkship, to improve the necessary skills for future referring physicians. Materials and methods A new required and graded module was introduced in 2014 into the radiology clerkship in year three of medical school: the Mystery Case. Each student was provided a unique and undifferentiated case from a dedicated teaching file containing de-identified images and requisition data. Students were expected to complete three serial tasks over one week: 1) prepare a voice recognition-derived, structured radiological report utilizing appropriate and relevant vocabulary; 2) discuss pertinent additional clinical information; and 3) discuss appropriate follow-up imaging, in addition to information on how to best prepare patients for these potential patient exams (e.g., with or without contrast, bowel preparation, and length of study). Students were provided written examples and dedicated class instruction with interactive discussions covering specific cases and associated related cases through random pairing with radiology resident and attending mentors. At the close of the week, students gave brief oral presentations of their cases and submitted the tasks for a written evaluation. Upon completion of the clerkship, the students completed a Likert-type six-item survey to evaluate the perceived improvement in select skills. Results The survey was completed by 82% (54/66) of the enrolled students, with 85% finding the Mystery Case an effective use of time. Medical students perceived an improved awareness of the patient care process (77%), awareness of the medical imaging resources available (89%), ability to understand a radiology report (74%), and ability to advise patients (69%). Conclusion Introduction of the Mystery Case as a graded exercise in the medical school radiology clerkship was perceived by students as effective use of time, with an improvement in the skills essential for future referring physicians.

Utility and Outcomes of Imaging Evaluation for Palpable Lumps in the Postmastectomy Patient.

OBJECTIVE. The objective of our study was to assess the utility of targeted breast ultrasound and mammography in evaluating palpable lumps in the mastectomy bed. MATERIALS AND METHODS. This retrospective study identified postmastectomy patients who presented for initial imaging evaluation of palpable lumps between January 2009 and December 2015. Clinical, imaging, and pathology results were reviewed. Surgical reconstruction type and percutaneous sampling data were collected. Patients were excluded if they had known malignancy at imaging presentation, if the palpable lump was not at the mastectomy site, or if there was less than 1 year clinical or imaging follow-up in the absence of biopsy. Each palpable site was assigned as a case, and analyses were performed at the case level. RESULTS. Among the 101 patients with a history of prophylactic or therapeutic mastectomy who presented during the study period, 118 palpable cases met the inclusion criteria. All 118 cases were evaluated with ultrasound and 43 with mammography. Among the 75 cases evaluated with ultrasound alone, nine cancers were detected. Among the 43 cases evaluated with both ultrasound and mammography, three cancers were sonographically detected, of which two were mammographically visible and one was mammographically occult. There were two false-negative ultrasound cases; both underwent sampling because of the level of clinical suspicion. In total, 14 palpable lumps in 12 patients were malignant, and 104 palpable lumps in 89 patients were nonmalignant. Targeted ultrasound yielded a negative predictive value (NPV) of 97% and a positive predictive value 2 of 27%. CONCLUSION. Our data suggest that targeted breast ultrasound, with its high NPV, should be the initial imaging test of choice for palpable lumps after mastectomy. Mammography yielded no additional cancers but was helpful in confirming benign diagnoses. The two false-negative ultrasound cases support palpation-guided sampling for imaging-occult and clinically suspicious palpable lumps.

Breast implant-associated anaplastic large cell lymphoma: Clinical and imaging findings at a large US cancer center.

PURPOSE: Evaluate the clinical presentation and imaging findings of breast implant-associated anaplastic large cell lymphoma (BIA ALCL) at a large US cancer center. MATERIALS AND METHODS: HIPAA-compliant IRB approved retrospective study, for which informed consent was waived. The Hospital Information System was screened for women who underwent implant reconstruction and were diagnosed with BIA ALCL between 2010 and 2016. Two radiologists reviewed images in consensus. Clinical and imaging characteristics were summarized using means and ranges for continuous variables and percentages for categorical variables. RESULTS: Patient cohort included 11 women with BIA ALCL (mean age at diagnosis = 54 years, range: 35-77), including women with (9/11) and without (2/11) history of breast cancer. Mean time from breast implant placement to diagnosis was 10 years (range: 6-14). BIA ALCL was identified in patients with saline (4/11) and silicone (5/11) implants. Implants were textured in 7/11 (63%) and unknown in 4/11 (36%) cases. All patients presented with a peri-implant seroma, (9/11 documented on imaging). Two of 11 patients had a mass within this seroma. Ten of 11 patients (91%) presented with symptoms. CONCLUSIONS: Saline and silicone breast implants may predispose patients to a rare lymphoma subtype, BIA ALCL, which presents on imaging as a peri-implant fluid collection ± mass.

Appearance Constrained Semi-Automatic Segmentation from DCE-MRI is Reproducible and Feasible for Breast Cancer Radiomics: A Feasibility Study.

We present a segmentation approach that combines GrowCut (GC) with cancer-specific multi-parametric Gaussian Mixture Model (GCGMM) to produce accurate and reproducible segmentations. We evaluated GCGMM using a retrospectively collected 75 invasive ductal carcinoma with ERPR+ HER2- (n = 15), triple negative (TN) (n = 9), and ER-HER2+ (n = 57) cancers with variable presentation (mass and non-mass enhancement) and background parenchymal enhancement (mild and marked). Expert delineated manual contours were used to assess the segmentation performance using Dice coefficient (DSC), mean surface distance (mSD), Hausdorff distance, and volume ratio (VR). GCGMM segmentations were significantly more accurate than GrowCut (GC) and fuzzy c-means clustering (FCM). GCGMM's segmentations and the texture features computed from those segmentations were the most reproducible compared with manual delineations and other analyzed segmentation methods. Finally, random forest (RF) classifier trained with leave-one-out cross-validation using features extracted from GCGMM segmentation resulted in the best accuracy for ER-HER2+ vs. ERPR+/TN (GCGMM 0.95, expert 0.95, GC 0.90, FCM 0.92) and for ERPR + HER2- vs. TN (GCGMM 0.92, expert 0.91, GC 0.77, FCM 0.83).

MRI features predictive of negative surgical margins in patients with HER2 overexpressing breast cancer undergoing breast conservation.

Here we develop a tool to predict resectability of HER2+ breast cancer at breast conservation surgery (BCS) utilizing features identified on preoperative breast MRI. We identified patients with HER2+ breast cancer who obtained pre-operative breast MRI and underwent BCS between 2002-2013. From the contoured tumor on pre-operative MRI, shape, histogram, and co-occurrence and size zone matrix texture features were extracted. In univariate analysis, Spearman's correlation coefficient (Rs) was used to assess the correlation between each image feature and an endpoint (surgical re-excision). For multivariate modeling, we employed a support vector machine (SVM) method in a manner of leave-one-out cross-validation (LOOCV). Of 109 patients with HER2+breast cancer who underwent BCS, 39% underwent surgical re-excision. 62% had residual cancer at re-excision. In univariate analysis, solidity (Rs = -0.32, p = 0.009) and extent (Rs = -0.29, p = 0.019) were significantly associated with re-excision. Skewness in post-contrast 1, 2, and 3 (Rs = 0.25, p = 0.045; Rs = 0.30, p = 0.015; Rs = 0.28, p = 0.026) and kurtosis in post-contrast 1 (Rs = 0.26, p = 0.035) were also statistically significant. LOOCV-based SVM test achieved 74.4% specificity and 71.4% sensitivity when 21 features were used. Thus, tumor texture, histogram and morphological MRI features may assist surgical planning, encouraging wide margins or mastectomy in patients who may otherwise go on to re-excision.

Multicenter Research Studies in Radiology.

RATIONALE AND OBJECTIVES: Here we review the current state of multicenter radiology research (MRR), and utilize a survey of experienced researchers to identify common advantages, barriers, and resources to guide future investigators. MATERIALS AND METHODS: The Association of University Radiologists established a Radiology Research Alliance task force, Multi-center Research Studies in Radiology, composed of 12 society members to review MRR. A REDCap survey was designed to gain more insight from experienced researchers. Recipients were authors identified from a PubMed database search, utilizing search terms "multicenter" or "multisite" and "radiology." The survey included investigator background information, reasons why, barriers to, and resources that investigators found helpful in conducting or participating in MRR. RESULTS: The survey was completed by 23 of 80 recipients (29%), the majority (76%) of whom served as a primary investigator on at least one MRR project. Respondents reported meeting collaborators at national or international (74%) and society (39%) meetings. The most common perceived advantages of MRR were increased sample size (100%) and improved generalizability (91%). External funding was considered the most significant barrier to MRR, reported by 26% of respondents. Institutional funding, setting up a central picture archiving and communication system, and setting up a central database were considered a significant barrier by 30%, 22%, and 22% of respondents, respectively. Resources for overcoming barriers included motivated staff (74%), strong leadership (70%), regular conference calls (57%), and at least one face-to-face meeting (57%). CONCLUSIONS: Barriers to MRR include funding and establishing a central database and a picture archiving and communication system. Upon embarking on an MRR project, forming a motivated team who meets and speaks regularly is essential.

Lymph node wire localization post-chemotherapy: Towards improving the false negative sentinel lymph node biopsy rate in breast cancer patients.

PURPOSE: To evaluate whether the disease status of the pre-neoadjuvant chemotherapy (NAC) core biopsied lymph node (preNACBxLN) in patients with node positive breast cancer corresponds to nodal status of all surgically retrieved lymph nodes (LNs) post-NAC and whether wire localization of this LN is feasible. MATERIALS AND METHODS: HIPPA compliant IRB approved retrospective study including breast cancer patients (a.) with preNACBxLN confirmed metastases, (b.) who received NAC, and (c.) underwent wire localization of the preNACBxLN. Electronic medical records were reviewed. Fisher's exact test was used to compare differences in residual disease post-NAC among breast cancer subtypes. RESULTS: 28 women with node positive breast cancer underwent ultrasound guided wire localization of the preNACBxLN, without complication. There was no evidence of residual nodal disease for 16 patients, with mean 4.4 (median 4) LNs resected. 12 patients had residual nodal metastases, with mean 9.2 (median 7) LNs resected and mean 2.3 (median 2) LNs with tumor involvement. 11 patients had metastases detected within the localized LN. One patient had micrometastasis in a sentinel LN, despite no residual disease in the preNACBxLN. Patients with luminal A/B breast cancer more often had residual nodal metastases (86%) at pathology, as compared to patients with HER2+ (20%) and Triple Negative breast cancer (50%), though not quite achieving statistical significance (p=0.055). CONCLUSION: Ultrasound guided wire localization of the preNACBxLN is feasible and may improve detection of residual tumor in patients post-NAC.

Incidental focal uptake in the breast and axilla on FDG PET: Clinical considerations and differential diagnosis.

Incidental focal FDG uptake in the breast or axilla on PET/CT performed for evaluation of extra-mammary primary disease presents a diagnostic challenge. Radiologists must consider a broad differential diagnosis, assess clinical history, and judiciously employ other imaging modalities such as mammography, ultrasound and MRI in the pursuit of findings which help narrow the differential diagnosis. Tissue sampling may be reserved for nondiagnostic imaging scenarios.

Whole body metabolic tumor volume is a prognostic marker in patients with newly diagnosed stage 3B non-small cell lung cancer, confirmed with external validation.

PURPOSE: TNM Stage 3B encompasses a wide range of primary tumor and nodal metastatic tumor burden. This study aimed to evaluate the prognostic value of quantitative FDG PET/CT parameters in patients with newly diagnosed Stage 3B Non-Small Cell Lung Cancer (NSCLC). MATERIALS AND METHODS: Institutional review board approved retrospective study identified patients diagnosed with Stage 3B NSCLC (8th edition TNM classification) on baseline FDG PET/CT at two medical centers (Medical centers A and B), between Feb 2004 and Dec 2014. Patients were excluded if they had prior NSCLC treatment or recent diagnosis of a second primary cancer. Quantitative FDG PET/CT parameters including whole body metabolic tumor volume (MTVwb), total lesion glycolysis (TLGwb), and maximum standardized uptake value (SUVmaxwb) were measured from baseline PET/CT using Edge method with Mimvista software. The primary endpoint was overall survival (OS). Cox proportional hazard regression and Kaplan-Meier overall survival analyses were used to test for an association between OS and quantitative FDG PET/CT parameters. The distributions of MTVwb, TLGwb, SUVmaxwb were skewed, so a natural logarithm transformation was applied and the transformed variables [(ln(MTVwb), ln(TLGwb), and ln(SUVmaxwb)] were used in the analysis. RESULTS: The training set included 110 patients from center A with Stage 3B NSCLC. 78.2% of patients expired during follow-up. Median OS was 14 months. 1-year, 2-year, and 5-year OS was 56.5%, 34.6% and 13.9%, respectively. Univariate Cox regression analysis showed no significant difference in OS on the basis of age, gender, histology, ln(TLGwb), or ln(SUVmaxwb). ln(MTVwb) was positively associated with OS [hazard ratio (HR) of 1.23, p = 0.037]. This association persisted on multivariate Cox regression analysis (HR 1.28, p = 0.043), with adjustments for age, gender, treatment and tumor histology. External validation with 44 patients from center B confirmed increasing MTVwb was associated significantly worse OS. An MTVwb cut-off point of 85.6 mL significantly stratified Stage 3B NSCLC patient prognosis. CONCLUSION: MTVwb is a prognostic marker for OS in patients with Stage 3B NSCLC, independent of age, gender, treatment, and tumor histology.

Breast cancer molecular subtype classifier that incorporates MRI features.

PURPOSE: To use features extracted from magnetic resonance (MR) images and a machine-learning method to assist in differentiating breast cancer molecular subtypes. MATERIALS AND METHODS: This retrospective Health Insurance Portability and Accountability Act (HIPAA)-compliant study received Institutional Review Board (IRB) approval. We identified 178 breast cancer patients between 2006-2011 with: 1) ERPR + (n = 95, 53.4%), ERPR-/HER2 + (n = 35, 19.6%), or triple negative (TN, n = 48, 27.0%) invasive ductal carcinoma (IDC), and 2) preoperative breast MRI at 1.5T or 3.0T. Shape, texture, and histogram-based features were extracted from each tumor contoured on pre- and three postcontrast MR images using in-house software. Clinical and pathologic features were also collected. Machine-learning-based (support vector machines) models were used to identify significant imaging features and to build models that predict IDC subtype. Leave-one-out cross-validation (LOOCV) was used to avoid model overfitting. Statistical significance was determined using the Kruskal-Wallis test. RESULTS: Each support vector machine fit in the LOOCV process generated a model with varying features. Eleven out of the top 20 ranked features were significantly different between IDC subtypes with P < 0.05. When the top nine pathologic and imaging features were incorporated, the predictive model distinguished IDC subtypes with an overall accuracy on LOOCV of 83.4%. The combined pathologic and imaging model's accuracy for each subtype was 89.2% (ERPR+), 63.6% (ERPR-/HER2+), and 82.5% (TN). When only the top nine imaging features were incorporated, the predictive model distinguished IDC subtypes with an overall accuracy on LOOCV of 71.2%. The combined pathologic and imaging model's accuracy for each subtype was 69.9% (ERPR+), 62.9% (ERPR-/HER2+), and 81.0% (TN). CONCLUSION: We developed a machine-learning-based predictive model using features extracted from MRI that can distinguish IDC subtypes with significant predictive power. J. Magn. Reson. Imaging 2016;44:122-129.

The Potential of High Resolution Magnetic Resonance Microscopy in the Pathologic Analysis of Resected Breast and Lymph Tissue.

Pathologic evaluation of breast specimens requires a fixation and staining procedure of at least 12 hours duration, delaying diagnosis and post-operative planning. Here we introduce an MRI technique with a custom-designed radiofrequency resonator for imaging breast and lymph tissue with sufficient spatial resolution and speed to guide pathologic interpretation and offer value in clinical decision making. In this study, we demonstrate the ability to image breast and lymphatic tissue using 7.0 Tesla MRI, achieving a spatial resolution of 59 × 59 × 94 µm(3) with a signal-to-noise ratio of 15-20, in an imaging time of 56 to 70 minutes. These are the first MR images to reveal characteristic pathologic features of both benign and malignant breast and lymph tissue, some of which were discernible by blinded pathologists who had no prior training in high resolution MRI interpretation.

Appearance of untreated bone metastases from breast cancer on FDG PET/CT: importance of histologic subtype.

PURPOSE: To determine if the histology of a breast malignancy influences the appearance of untreated osseous metastases on FDG PET/CT. METHODS: This retrospective study was performed under IRB waiver. Our Hospital Information System was screened for breast cancer patients who presented with osseous metastases, who underwent FDG PET/CT prior to systemic therapy or radiotherapy from 2009 to 2012. Patients with invasive ductal carcinoma (IDC), invasive lobular carcinoma (ILC), or mixed ductal/lobular (MDL) histology were included. Patients with a history of other malignancies were excluded. PET/CT was evaluated, blinded to histology, to classify osseous metastases on a per-patient basis as sclerotic, lytic, mixed lytic/sclerotic, or occult on CT, and to record SUVmax for osseous metastases on PET. RESULTS: Following screening, 95 patients who met the inclusion criteria (74 IDC, 13 ILC, and 8 MDL) were included. ILC osseous metastases were more commonly sclerotic and demonstrated lower SUVmax than IDC metastases. In all IDC and MDL patients with osseous metastases, at least one was FDG-avid. For ILC, all patients with lytic or mixed osseous metastases demonstrated at least one FDG-avid metastasis; however, in only three of seven patients were sclerotic osseous metastases apparent on FDG PET. CONCLUSION: The histologic subtype of breast cancer affects the appearance of untreated osseous metastases on FDG PET/CT. In particular, non-FDG-avid sclerotic osseous metastases were more common in patients with ILC than in patients with IDC. Breast cancer histology should be considered when interpreting non-FDG-avid sclerotic osseous lesions on PET/CT, which may be more suspicious for metastases (rather than benign lesions) in patients with ILC.