Has the mammography quality standards act affected the mammography quality in North Carolina?

Evolution of mammographic image quality in the state of Rio de Janeiro

OBJECTIVE

To evaluate the evolution of mammographic image quality in the state of Rio de Janeiro on the basis of parameters measured and analyzed during health surveillance inspections in the period from 2006 to 2011.

MATERIALS AND METHODS

Descriptive study analyzing parameters connected with imaging quality of 52 mammography apparatuses inspected at least twice with a one-year interval.

RESULTS

Amongst the 16 analyzed parameters, 7 presented more than 70% of conformity, namely: compression paddle pressure intensity (85.1%), films development (72.7%), film response (72.7%), low contrast fine detail (92.2%), tumor mass visualization (76.5%), absence of image artifacts (94.1%), mammography-specific developers availability (88.2%). On the other hand, relevant parameters were below 50% conformity, namely: monthly image quality control testing (28.8%) and high contrast details with respect to microcalcifications visualization (47.1%).

CONCLUSION

The analysis revealed critical situations in terms of compliance with the health surveillance standards. Priority should be given to those mammography apparatuses that remained non-compliant at the second inspection performed within the one-year interval.

Effects of quality assurance regulatory enforcement on performance of mammography systems: evidence from large-scale surveys in Taiwan

OBJECTIVE

The Standards for Medical Exposure Quality Assurance in mammography systems were enacted on July 1, 2008, in Taiwan. This study aimed to evaluate the trends in performance of mammography units before and after the regulation started on the basis of annual on-site surveys from 2008 to 2010.

MATERIALS AND METHODS

On-site measurements were conducted on 215, 205, and 209 mammography units in 2008, 2009, and 2010, respectively, which accounted for more than 95% of all units in Taiwan. Phantom image quality, average glandular dose (AGD), and half-value layer were evaluated on all systems. Processor conditions, compression conditions, radiation output, and computed radiography exposure indicators were assessed on units participating in mammography screening in 2008 and on all units in the later years. Evaluations of maximum compression force and automatic exposure control reproducibility were added into the protocol from 2009 onward.

RESULTS

Mean phantom scores were improved significantly from 2008 to 2009 (11.63 ± 1.30 vs 12.31 ± 0.94, p < 0.05) and remained stable for 2010 (12.35 ± 0.87). Mean AGDs were 1.48 ± 0.47, 1.38 ± 0.41, and 1.37 ± 0.42 mGy over the 3 years, with a significant reduction from 2008 to 2009 (p < 0.05). For film-screen mammography systems, variations of sensitometric curves were greatly reduced in 2009 and 2010 when compared with 2008. Passing rates were increased after the regulation took effect in almost all aspects.

CONCLUSION

Results from large-scale on-site surveys showed an overall improvement in performance after quality assurance in mammography was enforced in Taiwan.

Getting it right: are regulation and registries for CT radiation dose in children the answer?

Recently, the state of California enacted a law requiring radiologists to record the radiation dose that each patient receives for a CT scan. Failure to do so is penalized by law. This law becomes effective in July 2012. By July 2013, every facility that performs CT scans must become accredited by one of three professional groups. This report discusses the role that legislation is playing in the practice of medicine in regard to CT practice. Inherent in this discussion is the assumption that pediatric radiologists know the right dose that a child should receive for a specific clinical indication. But do we really know the answer to this? Compared to the European radiology community, the United States radiology community lags in this regard. This paper defines diagnostic reference levels (DRL) and reviews the history of DRL in the United States compared to that in the European community and the progress by the American College of Radiology's National Radiology Data Registry (NRDR) to establish national registries. The establishment of the first pediatric Quality Improvement Registry in CT Scans in Children (QuIRCC) and its progress to date will be discussed.

Digital mammography: effects of reduced radiation dose on diagnostic performance

PURPOSE

To experimentally determine the relationship between radiation dose and observer accuracy in the detection and discrimination of simulated lesions for digital mammography.

MATERIALS AND METHODS

This HIPAA-compliant study received institutional review board approval; the informed consent requirement was waived. Three hundred normal craniocaudal images were selected from an existing database of digital mammograms. Simulated mammographic lesions that mimicked benign and malignant masses and clusters of microcalcifications (3.3-7.4 cm in diameter) were then superimposed on images. Images were rendered without and with added radiographic noise to simulate effects of reducing the radiation dose to one half and one quarter of the clinical dose. Images were read by five experienced breast imaging radiologists. Results were analyzed to determine effects of reduced dose on overall interpretation accuracy, detection of microcalcifications and masses, discrimination between benign and malignant masses, and interpretation time.

RESULTS

Overall accuracy decreased from 0.83 with full dose to 0.78 and 0.62 with half and quarter doses, respectively. The decrease associated with transition from full dose to quarter dose was significant (P < .01), primarily because of an effect on detection of microcalcifications (P < .01) and discrimination of masses (P < .05). The level of dose reduction did not significantly affect detection of malignant masses (P > .5). However, reduced dose resulted in an increased mean interpretation time per image by 28% (P < .0001).

CONCLUSION

These findings suggest that dose reduction in digital mammography has a measurable but modest effect on diagnostic accuracy. The small magnitude of the effect in response to the drastic reduction of dose suggests potential for modest dose reductions in digital mammography.

Testing the effect of computer-assisted detection on interpretive performance in screening mammography

OBJECTIVE

The objective of our study was to test whether the use of computer-assisted detection (CAD) improves sensitivity at no cost to specificity for the detection of breast cancer and enables more accurate assessment of fatty breast tissue compared with dense breast tissue.

MATERIALS AND METHODS

We created a stratified random sample of screening mammograms weighted with difficult cases split evenly among women with fatty breast tissue and those with dense breast tissue: 114 patients were cancer-free, 114 had cancer 1 year after screening, and 113 had cancer 13-24 months after screening. In test settings 6 months apart, 19 community radiologists interpreted 341 bilateral screening mammograms with and without CAD. We compared the sensitivity and specificity using regression models adjusting for repeated measures.

RESULTS

CAD assistance did not affect overall sensitivity (cancer by 1 year: 63.2% without CAD and 62.0% with CAD; cancer in 13-24 months: 33.5% without CAD and 32.3% with CAD), but its effect differed for visible masses that were marked by CAD compared with those that were not marked by CAD (hereafter referred to as "unmarked"). CAD was associated with improved sensitivity for marked visible cancers and decreased sensitivity for unmarked visible masses; the sensitivities without and with CAD, respectively, were as follows: marked cancer by 1 year, 82.7% versus 83.1%; marked cancer in 13-24 months, 44.2% versus 57.9%; unmarked cancer by 1 year, 37.4% versus 30.1%; unmarked cancer in 13-24 months, 29.7% versus 23.0% (p < 0.03 for both interactions between assistance and CAD marking for cancer by 1 year and cancer in 13-24 months). CAD marked 77% (70/91) of the visible cancers by 1 year and 67.3% (37/55) of the visible cancers in 13-24 months. CAD marked more visible calcified lesions (86%) than masses and asymmetric densities (67%) (p < 0.05). Overall specificity was 72% without and 75% with CAD (p < 0.02). CAD had a greater effect on both specificity (p < 0.02) and sensitivity (p < 0.03) among radiologists who interpret more than 50 mammograms per week. The results were the same for fatty breast tissue and dense breast tissue.

CONCLUSION

In this experiment, CAD increased interpretive specificity but did not affect sensitivity because visible noncalcified lesions that went unmarked by CAD were less likely to be assessed as abnormal by radiologists. Breast density did not affect CAD's performance.

Global quality control perspective for the physical and technical aspects of screen-film mammography--image quality and radiation dose

The systematic monitoring of image quality and radiation dose is an ultimate solution to ensuring the continuously high quality of mammography examination. At present several protocols exist around the world, and different test objects are used for quality control (QC) of the physical and technical aspects of screen-film mammography. This situation may lead to differences in radiation image quality and dose reported. This article reviews the global QC perspective for the physical and technical aspects of screen-film mammography with regard to image quality and radiation dose. It points out issues that must be resolved in terms of radiation dose and that also affect the comparison.

Breast US: assessment of technical quality and image interpretation

PURPOSE

To determine whether ultrasonography (US) of the breast performed at a wide range of clinical practices conforms to the American College of Radiology (ACR) standards for quality and to assess the interpretations of breast sonograms.

MATERIALS AND METHODS

Static images from 152 breast US examinations performed at 86 institutions were evaluated for compliance with ACR guidelines for breast US hardware, technical factors, imaging protocol, and image annotation. Official interpretations submitted by the referring facilities were compared with static images submitted by the facility. Discrepancies were confirmed by two dedicated breast radiologists after repeat imaging, short-interval follow-up imaging, or biopsy.

RESULTS

A total of 60.5% of cases did not comply with at least one ACR guideline on breast US and included 9.2% of cases with inadequate equipment, 14.7% of cases with inappropriate focal zone placement, at least 14% of cases with static images in only one imaging plane, and 25% of cases with incomplete patient identifiers. Clinically relevant interpretation errors and interpretation discrepancies were confirmed in 23 (15.1%) of 152 cases.

CONCLUSION

The majority of breast US examinations did not comply with at least some of the standards for quality set forth by the ACR. Attention to these basic standards could substantially improve image quality.