Karen S. Johnson

Ultrasound of the thyroid and parathyroid glands.

Ultrasound plays a prominent role in the management of thyroid disease and parathyroid adenomas. It can detect clinically impalpable thyroid nodules and characterize them as cystic, solid, or complex. Determining that a nodule is definitively benign or malignant is difficult, and so when indicated an ultrasound-guided fine-needle aspiration can be performed. In the follow-up of patients with thyroid cancer, ultrasound can be used alone or in conjunction with computed tomography (CT)/magnetic resonance imaging (MRI) to detect recurrent disease. Recurrences can be confirmed using ultrasound to guide fine-needle aspirations. To locate parathyroid adenomas, ultrasound is often used in conjunction with sestamibi scanning. If both studies agree on the location of the adenoma, the surgeon can perform focused surgery for its removal. In patients in whom the studies do not agree or in whom they do not detect the adenoma, further evaluation with CT or more preferably MRI is indicated.

Abbreviated Screening Protocol for Breast MRI: A Feasibility Study

RATIONALE AND OBJECTIVES To compare the performance of two shortened breast magnetic resonance imaging (MRI) protocols to a standard MRI protocol for breast cancer screening. MATERIALS AND METHODS In this Health Insurance Portability and Accountability Act compliant, institutional review board-approved pilot study, three fellowship-trained breast imagers evaluated 48 breast MRIs (24 normal, 12 benign, and 12 malignant) selected from a high-risk screening population. MRIs were presented in three viewing protocols, and a final Breast Imaging-Reporting and Data System assessment was recorded for each case. The first shortened protocol (abbreviated 1) included only fat-saturated precontrast T2-weighted, precontrast T1-weighted, and first pass T1-weighted postcontrast sequences. The second shortened protocol (abbreviated 2) included the abbreviated 1 protocol plus the second pass T1-weighted postcontrast sequence. The third protocol (full), reviewed after a 1-month waiting period, included a nonfat-saturated T1-weighted sequence, fat-saturated T2-weighted, precontrast T1-weighted, and three or four dynamic postcontrast sequences. Interpretation times were recorded for the abbreviated 1 and full protocols. Sensitivity and specificity were compared via a chi-squared analysis. This pilot study was designed to detect a 10% difference in sensitivity with a power of 0.8. RESULTS There was no significant difference in sensitivity between the abbreviated 1 (86%; P = .22) or abbreviated 2 (89%; P = .38) protocols and the full protocol (95%). There was no significant difference in specificity between the abbreviated 1 (52%; P = 1) or abbreviated 2 (45%; P = .34) protocols and the full protocol (52%). The abbreviated 1 and full protocol interpretation times were similar (2.98 vs. 3.56 minutes). CONCLUSIONS In this pilot study, reader performance comparing two shortened breast MRI protocols to a standard protocol in a screening cohort were similar, suggesting that a shortened breast MRI protocol may be clinically useful, warranting further investigation.

Can Breast Cancer Molecular Subtype Help to Select Patients for Preoperative MR Imaging

PURPOSE To assess whether breast cancer molecular subtype classified by surrogate markers can be used to predict the extent of clinically relevant disease with preoperative breast magnetic resonance (MR) imaging. MATERIALS AND METHODS In this HIPAA-compliant, institutional review board-approved study, informed consent was waived. Preoperative breast MR imaging reports from 441 patients were reviewed for multicentric and/or multifocal disease, lymph node involvement, skin and/or nipple invasion, chest wall and/or pectoralis muscle invasion, or contralateral disease. Pathologic reports were reviewed to confirm the MR imaging findings and for hormone receptors (estrogen and progesterone subtypes), human epidermal growth factor receptor type 2 (HER2 subtype), tumor size, and tumor grade. Surrogates were used to categorize tumors by molecular subtype: hormone receptor positive and HER2 negative (luminal A subtype); hormone receptor positive and HER2 positive (luminal B subtype); hormone receptor negative and HER2 positive (HER2 subtype); hormone receptor negative and HER2 negative (basal subtype). All patients included in the study had a histologic correlation with MR imaging findings or they were excluded. χ(2) analysis was used to compare differences between subtypes, with multivariate logistic regression analysis used to assess for variable independence. RESULTS Identified were 289 (65.5%) luminal A, 45 (10.2%) luminal B, 26 (5.9%) HER2, and 81 (18.4%) basal subtypes. Among subtypes, significant differences were found in the frequency of multicentric and/or multifocal disease (luminal A, 27.3% [79 of 289]; luminal B, 53.3% [24 of 45]; HER2, 65.4% [17 of 26]; basal, 27.2% [22 of 81]; P < .001) and lymph node involvement (luminal A, 17.3% [50 of 289]; luminal B, 35.6% [26 of 45]; HER2, 34.6% [nine of 26]; basal 24.7% [20 of 81]; P = .014). Multivariate analysis showed that molecular subtype was independently predictive of multifocal and/or multicentric disease. CONCLUSION Preoperative breast MR imaging is significantly more likely to help detect multifocal and/or multicentric disease and lymph node involvement in luminal B and HER2 molecular subtype breast cancers. Molecular subtype may help to select patients for preoperative breast MR imaging.

Lobular breast cancer series: imaging

The limitations of mammography in the detection and evaluation of invasive lobular carcinoma (ILC) have long been recognized, presenting real clinical challenges in treatment planning for these tumors. However, advances in mammography, ultrasound, and magnetic resonance imaging present opportunities to improve the diagnosis and preoperative assessment of ILC. The evidence supporting the performance of each imaging modality will be reviewed, specifically as it relates to the pathology of ILC and its subtypes. Further, we will discuss emerging technologies that may be employed to enhance the detection rate and ultimately result in more effective screening and staging of ILC.

Interobserver Variability Between Breast Imagers Using the Fifth Edition of the BI-RADS MRI Lexicon.

OBJECTIVE The purpose of this study was to assess the interobserver variability of users of the MRI lexicon in the fifth edition of the BI-RADS atlas. MATERIALS AND METHODS Three breast imaging specialists reviewed 280 routine clinical breast MRI findings reported as BI-RADS category 3. Lesions reported as BI-RADS 3 were chosen because variability in the use of BI-RADS descriptors may influence which lesions are classified as probably benign. Each blinded reader reviewed every study and recorded breast features (background parenchymal enhancement) and lesion features (lesion morphology, mass shape, mass margin, mass internal enhancement, nonmass enhancement distribution, nonmass enhancement internal enhancement, enhancement kinetics) according to the fifth edition of the BI-RADS lexicon and provided a final BI-RADS assessment. Interobserver variability was calculated for each breast and lesion feature and for the final BI-RADS assessment. RESULTS Interobserver variability for background parenchymal enhancement was fair (ĸ = 0.28). There was moderate agreement on lesion morphology (ĸ = 0.53). For masses, there was substantial agreement on shape (ĸ = 0.72), margin (ĸ = 0.78), and internal enhancement (ĸ = 0.69). For nonmass enhancement, there was substantial agreement on distribution (ĸ = 0.69) and internal enhancement (ĸ = 0.62). There was slight agreement on lesion kinetics (ĸ = 0.19) and final BI-RADS assessment (ĸ = 0.11). CONCLUSION There is moderate to substantial agreement on most MRI BI-RADS lesion morphology descriptors, particularly mass and nonmass enhancement features, which are important predictors of malignancy. Considerable disagreement remains, however, among experienced readers whether to follow particular findings.

Cancelation of MRI Guided Breast Biopsies for Suspicious Breast Lesions Identified at 3.0 T MRI: Reasons, Rates, and Outcomes

RATIONALE AND OBJECTIVES To determine the cancelation rate of magnetic resonance imaging (MRI)-guided procedures in suspicious breast lesions initially detected at 3.0 Tesla (T) MRI. MATERIALS AND METHODS With institutional review board approval, a Health Insurance Portability and Accountability Act-compliant retrospective review of 117 suspicious 3.0 T MRI-detected lesions in 101 patients scheduled to undergo MRI-guided procedures was performed; informed consent was waived. Patient information, imaging features, and outcome data were collected and compared among completed and canceled procedures using Fishers exact test. RESULTS MRI-guided breast biopsies were canceled in 13% (15/117) because of lesion nonvisualization, including three (20%) masses, one (1%) focus, and 11 (73%) areas of nonmasslike enhancement. Median lesion size was 1.1 cm. Sixty percent (9/15) of nonvisualized lesions were associated with minimal or mild background parenchymal enhancement at MRI. The nonvisualization rate was not associated with patient age, menopausal status, lesion type, size, breast density, or background parenchymal enhancement (P > .7 for each). No cancers were detected at original lesion sites in 14 (93%) patients undergoing follow-up imaging (n = 11) or mastectomy (n = 3) for cancer elsewhere; one (7%) was lost to follow-up. CONCLUSION The MRI-guided breast biopsy cancelation rate from nonvisualization of suspicious lesions originally detected with 3.0 T MRI scanning was 13%, similar to rates reported for lesions detected at 1.0 and 1.5 T MRI. No cancers were detected on follow-up imaging. Canceling MRI-guided biopsies because of lesion nonvisualization is a reasonable approach if measures are taken to ensure lesion resolution at the time of biopsy and at imaging follow-up.

Predictors of Pain Experienced by Women During Percutaneous Imaging-Guided Breast Biopsies

PURPOSE The purpose of this study was to evaluate pain experienced during imaging-guided core-needle breast biopsies and to identify factors that predict increased pain perception during procedures. METHODS In this institutional review board-approved, HIPAA-compliant protocol, 136 women undergoing stereotactically or ultrasound-guided breast biopsy or cyst aspiration were recruited and provided written informed consent. Participants filled out questionnaires assessing anticipated biopsy pain, ongoing breast pain, pain experienced during biopsy, catastrophic thoughts about pain during biopsy, anxiety, perceived communication with the radiologist, chronic life stress, and demographic and medical information. Procedure type, experience level of the radiologist performing the biopsy, number of biopsies, breast density, histology, and tumor size were recorded for each patient. Data were analyzed using Spearmans ρ correlations and a probit regression model. RESULTS No pain (0 out of 10) was reported by 39.7% of women, mild pain (1-3 out of 10) by 48.5%, and moderate to severe pain (≥4 out of 10) by 11.8% (n = 16). Significant (P < .05) predictors of greater biopsy pain in the probit regression model included younger age, greater prebiopsy breast pain, higher anticipated biopsy pain, and undergoing a stereotactic procedure. Anticipated biopsy pain correlated most strongly with biopsy pain (β = .27, P = .004). CONCLUSIONS Most patients report minimal pain during imaging-guided biopsy procedures. Women experiencing greater pain levels tended to report higher anticipated pain before the procedure. Communication with patients before biopsy regarding minimal average pain reported during biopsy and encouragement to make use of coping strategies may reduce patient anxiety and anticipated pain.

Recurrence-free survival in breast cancer is associated with MRI tumor enhancement dynamics quantified using computer algorithms

PURPOSE The purpose of this study is to investigate the association between breast cancer recurrence-free survival and breast magnetic resonance imaging (MRI) tumor enhancement dynamics which are quantified semi-automatically using computer algorithms. METHODS In this retrospective IRB-approved study, we analyzed data from 275 breast cancer patients at a single institution. Recurrence-free survival data were obtained from the medical record. Routine clinical pre-operative breast MRIs were performed in all patients. The tumors were marked on the MRIs by fellowship-trained breast radiologists. A previously developed computer algorithm was applied to the marked tumors to quantify the enhancement dynamics relative to the automatically assessed background parenchymal enhancement. To establish whether the contrast enhancement feature quantified by the algorithm was associated with recurrence-free survival, we constructed a Cox proportional hazards regression model with the computer-extracted feature as a covariate. We controlled for tumor grade and size (major axis length), patient age, patient race/ethnicity, and menopausal status. RESULTS The analysis showed that the semi-automatically obtained feature quantifying MRI tumor enhancement dynamics was independently predictive of recurrence-free survival (p=0.024). CONCLUSION Semi-automatically quantified tumor enhancement dynamics on MRI are predictive of recurrence-free survival in breast cancer patients.

Frequency of Malignancy and Imaging Characteristics of Probably Benign Lesions Seen at Breast MRI

OBJECTIVE The purposes of this study were to evaluate the frequency, follow-up compliance, and cancer rate of MRI BI-RADS category 3 lesions and to determine the cancer rate for individual BI-RADS descriptors. MATERIALS AND METHODS A retrospective review was conducted of breast MRI examinations with an assessment of probably benign (BI-RADS category 3) from among 4279 consecutive breast MRI examinations performed from January 2005 through December 2009. The review revealed 282 (6.6%) examinations with 332 lesions defined as BI-RADS 3. Pathologic results, 2 years of follow-up imaging findings, or both were reviewed. The frequency of BI-RADS 3 assessments, follow-up imaging compliance, and cancer yield were calculated. Three fellowship-trained breast imagers reevaluated all lesions and recorded descriptors from the MRI lexicon of the fifth edition of the BI-RADS atlas. The distribution and likelihood of malignancy for each descriptor were calculated. RESULTS The follow-up compliance rate was 84.3% (280/332), and the malignancy rate was 4.3% (12/280). There were 50 (17.9%) individual foci, 61 (21.8%) multiple foci, 74 (26.4%) masses, and 95 (33.9%) nonmass enhancement lesions. Masses were most commonly oval (59.5% [44/74]), circumscribed (75.7% [56/74]), and homogeneously enhancing (43.2% [32/74]). Nonmass enhancement was most commonly focal (57.9% [55/95]) with heterogeneous enhancement (53.7% [51/95]) Most of the lesions had persistent kinetics (74.3% [208/280]). The background parenchymal enhancement was most commonly mild (51.1% [143/280]). CONCLUSION MRI BI-RADS category 3 is not frequently used, and the levels of patient compliance with follow-up imaging are acceptable. The cancer yield for probably benign lesions is greater for MRI-detected than for mammographically detected lesions, especially for specific BI-RADS descriptors.

Does Breast Imaging Experience During Residency Translate Into Improved Initial Performance in Digital Breast Tomosynthesis

PURPOSE To determine the initial digital breast tomosynthesis (DBT) performance of radiology trainees with varying degrees of breast imaging experience. METHODS To test trainee performance with DBT, we performed a reader study, after obtaining IRB approval. Two medical students, 20 radiology residents, 4 nonbreast imaging fellows, 3 breast imaging fellows, and 3 fellowship-trained breast imagers reviewed 60 unilateral DBT studies (craniocaudal and medio-lateral oblique views). Trainees had no DBT experience. Each reader recorded a final BI-RADS assessment for each case. The consensus interpretations from fellowship-trained breast imagers were used to establish the ground truth. Area under the receiver operating characteristic curve (AUC), sensitivity, and specificity were calculated. For analysis, first- through third-year residents were classified as junior trainees, and fourth-year residents plus nonbreast imaging fellows were classified as senior trainees. RESULTS The AUCs were .569 for medical students, .721 for junior trainees, .701 for senior trainees, and .792 for breast imaging fellows. The junior and senior trainee AUCs were equivalent (P < .01) using a two one-sided test for equivalence, with a significance threshold of 0.1. The sensitivities and specificities were highest for breast imaging fellows (.778 and .815 respectively), but similar for junior (.631 and .714, respectively) and senior trainees (.678 and .661, respectively). CONCLUSIONS Initial performance with DBT among radiology residents and nonbreast imaging fellows is independent of years of training. Radiology educators should consider these findings when developing educational materials.