Biomedical subjects

Katherine A Klein

Publications and source records attributed to Katherine A Klein.

3 recordsLinked to original sources

PubMed2006

Mammographic density measured with quantitative computer-aided method: comparison with radiologists' estimates and BI-RADS categories.

PURPOSE: To retrospectively compare computer-aided mammographic density estimation (MDEST) with radiologist estimates of percentage density and Breast Imaging Reporting and Data System (BI-RADS) density classification. MATERIALS AND METHODS: Institutional Review Board approval was obtained for this HIPAA-compliant study; patient informed consent requirements were waived. A fully automated MDEST computer program was used to measure breast density on digitized mammograms in 65 women (mean age, 53 years; range, 24-89 years). Pixel gray levels in detected breast borders were analyzed, and dense areas were segmented. Percentage density was calculated by dividing the number of dense pixels by the total number of pixels within the borders. Seven breast radiologists (five trained with MDEST, two not trained) prospectively assigned qualitative BI-RADS density categories and visually estimated percentage density on 260 mammograms. Qualitative BI-RADS assessments were compared with new quantitative BI-RADS standards. The reference standard density for this study was established by allowing the five trained radiologists to manipulate the MDEST gray-level thresholds, which segmented mammograms into dense and nondense areas. Statistical tests performed include Pearson correlation coefficients, Bland-Altman agreement method, kappa statistics, and unpaired t tests. RESULTS: There was a close correlation between the reference standard and radiologist-estimated density (R = 0.90-0.95) and MDEST density (R = 0.89). Untrained radiologists overestimated percentage density by an average of 37%, versus 6% for trained radiologists (P < .001). MDEST showed better agreement with the reference standard (average overestimate, 1%; range, -15% to +18%). MDEST correlated better with percentage density than with qualitative BI-RADS categories. There were large overlaps and ranges of percentage density in qualitative BI-RADS categories 2-4. Qualitative BI-RADS categories correlated poorly with new quantitative BI-RADS categories, and 16 (6%) of 260 views were erroneously classified by MDEST. CONCLUSION: MDEST compared favorably with radiologist estimates of percentage density and is more reproducible than radiologist estimates when qualitative BI-RADS density categories are used. Qualitative and quantitative BI-RADS density assessments differed markedly.

Adult↗

PubMed2005

Estimating the effects of informal radiology resident teaching on radiologist productivity: what is the cost of teaching?

RATIONALE AND OBJECTIVES: One mission of an academic radiology department is to teach. The greatest teaching effort is directed at radiology residents. As clinical work demands increase, informal, non-revenue-generating, teaching may suffer. We sought to determine the economic consequences of teaching. MATERIALS AND METHODS: With the use of a picture archiving and communications system, 6 radiology faculty members independently interpreted and dictated digitally acquired bone and chest radiographs for 1 hour alone and again 10-12 weeks later with a first-year resident. During the second session, the quality of teaching was graded by independent observers. The number of cases, relative value units (RVUs), and reimbursement for each session were calculated. RESULTS: The difference in number of cases dictated working alone (mean, 44.7) and with a first-year resident (mean, 23.5) was significant (P = 0.007). The difference between RVUs generated by faculty alone (mean, 9.0) and with a resident (mean, 4.5) also was significant (P = 0.006), and the difference in dollars billed when working alone (mean, $1558.45) and with a resident (mean, $777.65) was significant (P = 0.007). As teaching quality increased, the number of cases interpreted, dollars billed, and RVUs trended lower. CONCLUSION: Informal resident teaching significantly reduces clinical throughput, reducing examination volume, RVUs, and dollars billed by approximately half.

Bone and Bones↗

PubMed2004

Small (< 2.0-cm) breast cancers: mammographic and US findings at US-guided cryoablation--initial experience.

PURPOSE: To determine the mammographic and ultrasonographic (US) findings at cryoablation of small solitary invasive breast cancers and compare them with presence of residual malignancy after treatment. MATERIALS AND METHODS: Institutional review board approval and informed patient consent were obtained. Nine patients with small solitary invasive breast cancers diagnosed at core biopsy were treated with US-guided cryoablation and a 2.7-mm cryoprobe. Mean cancer size was 12 mm (range, 8-18 mm); four were palpable. Tabletop argon gas-based cryoablation system with a double-freeze-thaw protocol was used to treat cancers in outpatient setting. Tumor sites were excised at lumpectomy 2-3 weeks after cryoablation. Findings at mammography and US before, during, and after cryoablation were assessed to categorize densities and masses on mammograms and masses on US images with Breast Imaging Reporting and Data System (BI-RADS); maximum cancer size was measured. Imaging findings and clinical breast examination data were compared with histologic findings from lumpectomy specimens to determine presence of intraductal or invasive cancer. RESULTS: With US guidance, ice balls (maximal mean size, 4.4 cm) were formed around cancers. Before excision, eight patients underwent mammography; all had new focal densities (maximum size, 2.5-5.0 cm) at cancer sites. Six patients underwent preexcisional US; 100% of them had new hyperechogenicity in tissue surrounding cancer site. Seven (78%) of nine patients had no residual cancer; specimens contained fat necrosis. One patient had a small focus of invasive cancer; one had extensive multifocal ductal carcinoma in situ. Patients with BI-RADS category 1 or 2 densities on mammograms or nonpalpable tumors had no residual malignancy. No residual invasive cancer occurred in tumors 17 mm or smaller or in cancers without spiculated margins at US. CONCLUSION: After cryoablation, there was increased echogenicity at US and increased density at mammography; these findings were observed in areas that approximated location and size of the ice ball. Tumor size, mammographic density, and US characteristics may be indicators of likelihood of complete cryoablation.

Adenocarcinoma, Mucinous↗