Katherine A. Klein

Digital breast tomosynthesis is comparable to mammographic spot views for mass characterization.

PURPOSE To determine if digital breast tomosynthesis (DBT) performs comparably to mammographic spot views (MSVs) in characterizing breast masses as benign or malignant. MATERIALS AND METHODS This IRB-approved, HIPAA-compliant reader study obtained informed consent from all subjects. Four blinded Mammography Quality Standards Act-certified academic radiologists individually evaluated DBT images and MSVs of 67 masses (30 malignant, 37 benign) in 67 women (age range, 34-88 years). Images were viewed in random order at separate counterbalanced sessions and were rated for visibility (10-point scale), likelihood of malignancy (12-point scale), and Breast Imaging Reporting and Data System (BI-RADS) classification. Differences in mass visibility were analyzed by using the Wilcoxon matched-pairs signed-ranks test. Reader performance was measured by calculating the area under the receiver operating characteristic curve (A(z)) and partial area index above a sensitivity threshold of 0.90 (A(z)(0.90)) by using likelihood of malignancy ratings. Masses categorized as BI-RADS 4 or 5 were compared with histopathologic analysis to determine true-positive results for each modality. RESULTS Mean mass visibility ratings were slightly better with DBT (range, 3.2-4.4) than with MSV (range, 3.8-4.8) for all four readers, with one readers improvement achieving statistical significance (P = .001). The A(z) ranged 0.89-0.93 for DBT and 0.88-0.93 for MSV (P ≥ .23). The A(z)((0.90)) ranged 0.36-0.52 for DBT and 0.25-0.40 for MSV (P ≥ .20). The readers characterized seven additional malignant masses as BI-RADS 4 or 5 with DBT than with MSV, at a cost of five false-positive biopsy recommendations, with a mean of 1.8 true-positive (range, 0-3) and 1.3 false-positive (range, -1 to 4) assessments per reader. CONCLUSION In this small study, mass characterization in terms of visibility ratings, reader performance, and BI-RADS assessment with DBT was similar to that with MSVs. Preliminary findings suggest that MSV might not be necessary for mass characterization when performing DBT.

Cross-Sectional Examination Interpretation Discrepancies Between On-Call Diagnostic Radiology Residents and Subspecialty Faculty Radiologists: Analysis by Imaging Modality and Subspecialty

PURPOSE The aim of this study was to identify the rate of discrepancies between radiology residents and faculty radiologists at an academic hospital and to determine the distribution across subspecialties and modalities, specifically CT, MR, and ultrasound. METHODS Consecutive CT, MR, and ultrasound preliminary interpretations rendered by on-call second-year through fourth-year radiology residents for 9 months on emergency department patients, inpatients, and urgent outpatients formed the study population. All preliminary interpretations were graded using a modified RADPEER(®) system (scores 0 and 1 = concordance; score 2 = minor, clinically insignificant discordance; scores 3 and 4 = clinically significant discordance) by the subspecialty faculty members who rendered the final interpretation. RESULTS There were 158 clinically significant discrepancies out of 21,482 preliminary interpretations, for a discrepancy rate of 0.7%. There was no statistically significant difference in rates across subspecialties or between adult and pediatric examinations (cardiothoracic, 1%; abdominal, 0.7%; neuroradiology, 0.6%; musculoskeletal, 0.7%; pediatrics, 0.8%). MR and CT interpretations had significantly higher rates than ultrasound (MR, 1.4%; CT, 0.9%; ultrasound, 0.2%; P < .001). Within neuroradiology, there was a significantly higher rate for MR than CT (1.5% vs 0.6%, P < .01), and within abdominal radiology, there was a significantly higher rate for CT than ultrasound (1.1% vs 0.2%, P < .01). CONCLUSIONS Discrepancy rates in this study were less than or comparable with those reported previously and within or lower than rates for practicing radiologists. Discrepancy rates varied among subspecialties and modalities, suggesting the use of a RADPEER system with attention to modality and subspecialty as a methodology for identifying areas for targeted resident education.

Complicated Breast Cysts on Sonography: Is Aspiration Necessary to Exclude Malignancy?

RATIONALE AND OBJECTIVES To determine the incidence of breast cancer in women presenting for fine needle aspiration of sonographically diagnosed complicated breast cysts. MATERIALS AND METHODS Institutional review board approval was obtained. A retrospective study was performed of 186 consecutive women who presented for fine needle aspiration of 243 sonographic complicated cysts detected by clinical examination or imaging between January 2002 and August 2003. Sonographic complicated cysts were defined as those meeting most but not all criteria for simple cysts similar to current Breast Imaging Reporting and Data System classification. We excluded solid masses, cysts with solid components, intracystic masses, and simple cysts. Prospective mammography, ultrasound, and procedure reports were reviewed. A case was considered positive if cytology, core needle biopsy, or surgical excision was positive for cancer. Final diagnosis was established by biopsy, cytology, clinical resolution, or stability over time. RESULTS One of 243 (0.4%) lesions proved malignant (95% confidence interval 0-1.94%); 210/243 (86.4%) of cases yielded fluid on aspiration. Of 141 samples submitted to cytology, 138 (97.9%) were benign and 3 (2.1%) atypical. All cases of atypia were benign at surgical excision. Ninety five of 243 (39.1%) aspiration samples with typical cyst fluid were discarded. A total of 33/243 (13.6%) cases did not yield fluid, 1 of which was positive for cancer. Thirty cases underwent core needle or excisional biopsy for imaging discordance with benign results. CONCLUSIONS Breast cancer presenting as a complicated cyst by ultrasound was rare (0.4%, 95% confidence interval 0-1.94%). These results provide support for classification of complicated cysts as probably benign.

Prevalence of Malignancy in Thyroid Nodules with an Initial Nondiagnostic Result After Ultrasound Guided Fine Needle Aspiration

The objective of this study was to determine the rate of malignancy in thyroid nodules with an initial nondiagnostic fine needle aspiration. From October 2001 to April 2007, biopsies were performed on 1344 thyroid nodules in our practice. Biopsies were performed on nodules using 25-27 gauge needles, ultrasound guidance and multiple passes using both suction and capillary action. We retrospectively reviewed the results of these biopsies as well as any further management of nodules that received nondiagnostic results (IRB HUM00006459). Following initial biopsy, 295/1344 (21.9%) of nodules received nondiagnostic pathologic results. Of this population, 39 nodules (13.1%) were lost to follow-up. Of the remaining 256 nodules that received a repeat FNA, surgical excision, or greater than 24 months of clinical and imaging follow-up, only five cancers were detected, representing only 2% of the population that received an initial nondiagnostic biopsy result. All of these cancers were papillary neoplasms. When rigorous, ultrasound-guided, fine needle aspiration of thyroid nodules is performed, a nondiagnostic histopathologic result should not be interpreted as suspicious for thyroid cancer. Given the low rate of malignancy in this population (2%), we suggest that clinical and imaging follow-up of these nodules, opposed to repeat sampling, is warranted.

Imaging of Breast Cancer–Related Changes After Nonsurgical Therapy

OBJECTIVE The purpose of this article is to review both expected and unexpected thoracic CT manifestations of nonsurgical breast cancer treatment with multimodality imaging correlation. Specific topics include the spectrum of posttherapy changes attributed to chemotherapy and radiation therapy and the spread of breast cancer. CONCLUSION Thoracic CT is an important tool commonly used for breast cancer staging and surveillance and for diagnostic indications such as shortness of breath and chest pain. Imaging findings can be related to progression of disease or to associated conditions, such as pulmonary embolism. The hallmarks of breast cancer spread in the thorax include pulmonary nodules, enlarged lymph nodes, pleural effusions, thickening or nodularity, and sclerotic or lytic skeletal lesions. Less common findings including pulmonary lymphangitic tumor spread and pericardial metastasis. The findings also may represent the sequelae of surgery, radiation therapy, or chemotherapy for breast cancer. Knowledge of various treatment methods and their expected and unexpected CT findings is important for recognizing treatment-related abnormalities to avoid confusion with breast cancer spread and thereby minimize the risk that unnecessary further diagnostic imaging will be performed.

Simulation in Radiology Education: Thinking Outside the Phantom.

OBJECTIVE The purpose of this article is to discuss the use of simulation in radiology education. CONCLUSION Simulation is an engaging way to educate radiology trainees. It allows trainees to improve their procedural and clinical skills in a calm, supportive environment that optimizes patient safety. Familiarity with the principles of simulation education may help radiologists evaluate their training curricula to identify skills that could be augmented with simulation training.

Applied clinical anatomy: the successful integration of anatomy into specialty-specific senior electives

PurposeA strong foundation in anatomical knowledge is essential for physicians in all fields. Despite this established importance, anatomy continues to be primarily taught only during the pre-clinical years of medical school. Senior medical students have more mature clinical reasoning and analytical skills; therefore, advanced anatomy courses have great potential to integrate basic and clinical sciences to better prepare senior medical students for residency.MethodsAt our institution, five electives have been implemented that integrate anatomical education in clinical contexts in the fields of emergency medicine, musculoskeletal medicine, radiology, surgery, and obstetrics and gynecology. These 4-week courses are all offered in the spring of the final year of medical school. The course curricula, content, and evaluation data are described for each of the courses.ResultsThe five electives have been extremely popular at our institution, and all have been consistently filled each year by students entering diverse disciplines. Course evaluations have been positive and students specifically note how these courses allow them the opportunity to integrate basic anatomical knowledge into clinical contexts. Students have marked improvement in anatomical knowledge after completion of these electives.ConclusionsAdvanced anatomy courses that integrate anatomical education with clinical reasoning are important curricular innovations that are popular with students and lead to important improvements in anatomical knowledge. Anatomists can lead the charge for better integration of basic sciences into senior medical school curricula.

ROC study: effects of computer-aided diagnosis on radiologists' characterization of malignant and benign breast masses in temporal pairs of mammograms

We conducted an observer performance study using receiver operating characteristic (ROC) methodology to evaluate the effects of computer-aided diagnosis (CAD) on radiologists’ performance for characterization of masses on serial mammograms. The automated CAD system, previously developed in our laboratory, can classify masses as malignant or benign based on interval change information on serial mammograms. In this study, 126 temporal image pairs (73 malignant and 53 benign) from 52 patients containing masses on serial mammograms were used. The corresponding masses on each temporal pair were identified by an experienced radiologist and automatically segmented by the CAD program. Morphological, texture, and spiculation features of the mass on the current and the prior mammograms were extracted. The individual features and the difference between the corresponding current and prior features formed a multidimensional feature space. A subset of the most effective features that contained the current, prior, and interval change information was selected by a stepwise procedure and used as input predictor variables to a linear discriminant classifier in a leave-one-case-out training and testing resampling scheme. The linear discriminant classifier estimated the relative likelihood of malignancy of each mass. The classifier achieved a test Az value of 0.87. For the ROC study, 4 MQSA radiologists and 1 breast imaging fellow assessed the masses on the temporal pairs and provided estimates of the likelihood of malignancy without and with CAD. The average Az value for the likelihood of malignancy estimated by the radiologists was 0.79 without CAD and improved to 0.87 with CAD. The improvement was statistically significant (p=0.0003). This preliminary result indicated that CAD using interval change analysis can significantly improve radiologists’ accuracy in classification of masses and thereby may increase the positive predictive value of mammography.

Digital stereomammography: observer performance study of the effects of magnification and zooming on depth perception

We have previously reported the effects of stereo angle and exposure on depth discrimination and the use of virtual cursors for absolute depth measurements in digital stereomammography. The current study further investigates the effects of magnification and zooming on depth perception. Stereoscopic image pairs of a phantom were acquired with a full-field digital mammography system. The modular phantom contained 25 crossing fibril pairs with depth separations between each pair ranging from 2 to 10 mm. Three phantom (fibril) configurations were imaged using techniques of 30 kVp, Rh/Rh, +/- 3 degrees stereo angle, , contact and 1.8X magnification geometry, and 4 to 63 mAs exposure range. The images were displayed on a Barco monitor driven by a Metheus stereo graphics board and viewed with LCD stereo glasses. Five observers participated in the study. Each observer visually judged if the vertical fibril was in front of or behind the horizontal fibril in each pair. It was found that the accuracy of depth discrimination increased with increasing fibril depth separation and x-ray exposure. Zooming the contact stereo images by 2X did not improve the accuracy. Under conditions of high noise (low mAs) and small depth separation between the fibrils, depth discriminations were significantly better in stereo images acquired with geometric magnification than in images acquired with a contact technique and displayed with or without zooming. This study indicates that stereoscopic imaging, especially with magnification, may be useful for visualizing the spatial distribution of microcalcifications in a cluster and differentiating overlapping tissues from masses on mammograms.

Introducing First-Year Medical Students to Radiology: Implementation and Impact

RATIONALE AND OBJECTIVES The aims of our study were (1) to describe a new educational intervention for first-year medical students that gave a substantial, early exposure to radiology and (2) to examine how this early exposure was received by the students. MATERIALS AND METHODS Our new curriculum incorporated a new 2-week course very early in the M1 year entitled Foundations of Diagnostics and Therapeutics. Among other topics, the course included a substantial introduction to radiology primarily through small-group seminars and online materials, administered using a flipped-classroom approach. The students were given pre- and postcourse surveys that assessed the degree to which they felt prepared to learn about radiology, as well as their interest in radiology. Results were analyzed using the Wilcoxon signed-rank test. RESULTS Survey responses were obtained from 170 students before the course and 65 students afterward. Upon completing the course, students showed significantly increased academic interest in radiology (P = .008) and a heightened perception of the effect of radiology on patient care (P = .04), without a significant change in interest in pursuing radiology as a career. Students showed an overwhelmingly positive response to the course, although some noted that previous anatomy training would have been helpful. Eighty percent agreed or strongly agreed that the flipped-classroom structure was an effective educational model. CONCLUSIONS Our study demonstrated that students were very excited to gain exposure to radiology early in their medical school curriculum, and such exposure led to an improved perception of the field.