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Dag Pavic

Publications and source records attributed to Dag Pavic.

11 recordsLinked to original sources
PubMed2007

Feasibility of breast preserving therapy with single fraction in situ radiotherapy delivered intraoperatively.

BACKGROUND: Accelerated partial breast irradiation (APBI) has gained widespread interest as a means of improving the convenience and availability of breast conserving radiotherapy. Intraoperative radiation therapy (IORT) is an APBI technique that delivers breast radiotherapy as a single dose at the time of partial mastectomy. We adapted the technique of Veronesi to deliver IORT prior to tumor excision to improve delivery to the region at risk and reduce the volume of normal tissue irradiated. METHODS: Patients age >or=55 with ultrasonographically defined tumors <or=3 cm and invasive ductal carcinoma confirmed by core biopsy were eligible. Pre-operative ultrasound was performed at the time of needle localization and radiocolloid injection. IORT treatment planning was performed prior to surgery using ultrasound tumor definition, selecting cone size and electron energy to optimize dose distribution. In the operating room, the surgeon retracted the skin over the tumor, cone was placed and radiotherapy delivered. Standard partial mastectomy was then performed. RESULTS: Twenty-three patients were enrolled in the study. Eighteen patients completed IORT with 10 patients having successful IORT no additional local therapy necessary. In five patients, the intraoperative radiation therapy served as the boost and in three patients unsuspected larger tumors or multicentric disease necessitated a mastectomy. The majority of patients had a good to excellent cosmetic result. CONCLUSIONS: Single fraction in situ IORT prior to partial mastectomy is feasible for patients with small breast cancers in achieving a good to excellent cosmetic result. Based on this early preliminary data, we plan to expand our feasibility trial.

Aged↗
PubMed2006

Correlation of HER-2/neu overexpression with mammography and age distribution in primary breast carcinomas.

RATIONALE AND OBJECTIVES: HER-2/neu is a valuable prognostic and therapeutic marker in primary breast carcinoma. The objective of this study was to determine the mammographic and patient characteristics (age) that correlate with HER-2/neu overexpression in primary breast carcinoma. MATERIALS AND METHODS: HER-2/neu characteristics and preoperative mammograms were available in 498 patients with 543 primary breast carcinomas (526 invasive carcinomas and 17 ductal carcinoma in situ). HER-2/neu status was determined by immunohistochemistry and fluorescence in situ hybridization. For evaluation of patient age distribution, age was divided into 5 groups. For mammography, breast composition and abnormal findings were categorized. Abnormal findings were divided into mass, calcification, architectural distortion, asymmetric density, or none. RESULTS: For age distribution, women under than 50 years had more frequent HER-2/neu overexpression than women aged 60-69 years (P < .05). On mammography, there was no significant correlation between breast composition and HER-2/neu status (P > .05). Calcifications were more significantly frequent in carcinomas with HER-2/neu overexpression (56%) than in those without HER-2/neu overexpression (40%) (P = .001). Of the 242 carcinomas with calcifications on mammography, fine linear morphology was more significantly frequent in carcinomas with HER-2/neu overexpression (20%) when compared with those without HER-2/neu overexpression (10%) (P = .023). Diffuse distribution of calcifications was more common in carcinomas with HER-2/neu overexpression (11%) compared with carcinomas without HER-2/neu overexpression (5%) (P = .051). CONCLUSION: HER-2/neu overexpression in primary breast carcinoma is correlated with patients' age (under age 50) and calcifications at mammography.

Adult↗
PubMed2006

The positive predictive value for diagnosis of breast cancer full-field digital mammography versus film-screen mammography in the diagnostic mammographic population.

RATIONALE AND OBJECTIVES: Diagnostic mammography is performed on women with clinical symptoms that suggest breast cancer or women for whom further mammographic evaluation has been requested because of an abnormal screening mammography. We assessed whether the use of full-field digital mammography would improve the positive predictive value (PPV) for the diagnosis of breast cancer in a diagnostic population compared with film-screen mammography. MATERIALS AND METHODS: From January 2002 to December 2003, 11,621 patients underwent diagnostic mammography at the University of North Carolina Hospital, Chapel Hill. Among these 11,621 patients, 1400 lesions in 1121 patients underwent biopsy. We included the biopsy-performed lesions, so PPV3 was used for comparison of PPVs between film-screen mammography and full-field digital mammography. Six breast radiologists interpreted the images using the Breast Imaging Reporting and Data System of the American College of Radiology. PPV3s were compared between film-screen and full-field digital mammography in the entire study cohort and in specified subgroups according to different radiologists, breast density, and lesion type on mammography. The chi(2) and Fisher's exact tests were used for comparison of PPV3s between two modalities of mammography with the Bonferroni procedure for subgroup analysis. RESULTS: In the entire study cohort, PPV3s of full-field digital mammography and film-screen mammography were similar (difference in PPV3,-0.007; 95% confidence interval, -0.081 to 0.068; P = .8602). In predefined subgroups, there was no difference in PPV3 by the radiologist, breast density, or lesion type between two modalities of mammography (P > .005). CONCLUSION: There is no improvement in PPV for the diagnosis of breast cancer with full-field digital mammography compared with film-screen mammography in a large diagnostic population.

Adult↗
PubMed2006

Comparison of LCD and CRT displays based on efficacy for digital mammography.

RATIONALE AND OBJECTIVES: To compare two display technologies, cathode ray tube (CRT) and liquid crystal display (LCD), in terms of diagnostic accuracy for several common clinical tasks in digital mammography. MATERIALS AND METHODS: Simulated masses and microcalcifications were inserted into normal digital mammograms to produce an image set of 400 images. Images were viewed on one CRT and one LCD medical-quality display device by five experienced breast-imaging radiologists who rated the images using a categorical rating paradigm. The observer data were analyzed to determine overall classification accuracy, overall lesion detection accuracy, and accuracy for four specific diagnostic tasks: detection of benign masses, malignant masses, and microcalcifications, and discrimination of benign and malignant masses. RESULTS: Radiologists had similar overall classification accuracy (LCD: 0.83 +/- 0.01, CRT: 0.82 +/- 0.01) and lesion detection accuracy (LCD: 0.87 +/- 0.01, CRT: 0.85 +/- 0.01) on both displays. The difference in accuracy between LCD and CRT for the detection of benign masses, malignant masses, and microcalcifications, and discrimination of benign and malignant masses was -0.019 +/- 0.009, 0.020 +/- 0.008, 0.012 +/- 0.013, and 0.0094 +/- 0.011, respectively. Overall, the two displays did not exhibit any statistically significant difference (P > .05). CONCLUSION: This study explored the suitability of two different soft-copy displays for the viewing of mammographic images. It found that LCD and CRT displays offer similar clinical utility for mammographic tasks.

Breast Neoplasms↗
PubMed2005

A comparative study of mobile electronic data entry systems for clinical trials data collection.

PURPOSE: To determine the speed, accuracy, ease of use, and user satisfaction of various electronic data entry platforms for use in the collection of mammography clinical trials data. METHOD AND MATERIALS: Four electronic data entry platforms were tested: standalone personal digital assistant (PDA), Tablet PC, digitizer Tablet/PDA Hybrid (DTP Hybrid), and digital pen (d-pen). Standard paper data entry was used as control. Each of five radiologist readers was assigned to enter interpretations for 20 screening mammograms using three out of the five data entry methods. Assistants recorded both start and stop data entry times of the radiologists and the number of help requests made. Data were checked for handwriting recognition accuracy for the d-pen platform using handwriting verification software. A user satisfaction survey was administered at the end of each platform reading session. RESULTS: Tablet PC and d-pen were statistically equivalent to conventional pen and paper in initial data entry speed. Average verification time for d-pen was significantly less than secondary electronic data entry of paper forms (p-value <0.001). The number of errors in handwriting recognition for d-pen was less than secondary electronic data entry of the paper forms data. Users were most satisfied with Tablet PC, d-pen, and conventional pen and paper for data entry. CONCLUSIONS: Tablet PC and d-pen are equally fast and easy-to-use data entry methods that are well tolerated by radiologist users. Handwriting recognition review and correction for the d-pen is significantly faster and more accurate than secondary manual keyboard and mouse data entry.

Clinical Trials as Topic↗
PubMed2005

The effects of gray scale image processing on digital mammography interpretation performance.

RATIONALE AND OBJECTIVES: To determine the effects of three image-processing algorithms on diagnostic accuracy of digital mammography in comparison with conventional screen-film mammography. MATERIALS AND METHODS: A total of 201 cases consisting of nonprocessed soft copy versions of the digital mammograms acquired from GE, Fischer, and Trex digital mammography systems (1997-1999) and conventional screen-film mammograms of the same patients were interpreted by nine radiologists. The raw digital data were processed with each of three different image-processing algorithms creating three presentations-manufacturer's default (applied and laser printed to film by each of the manufacturers), MUSICA, and PLAHE-were presented in soft copy display. There were three radiologists per presentation. RESULTS: Area under the receiver operating characteristic curve for GE digital mass cases was worse than screen-film for all digital presentations. The area under the receiver operating characteristic for Trex digital mass cases was better, but only with images processed with the manufacturer's default algorithm. Sensitivity for GE digital mass cases was worse than screen film for all digital presentations. Specificity for Fischer digital calcifications cases was worse than screen film for images processed in default and PLAHE algorithms. Specificity for Trex digital calcifications cases was worse than screen film for images processed with MUSICA. CONCLUSION: Specific image-processing algorithms may be necessary for optimal presentation for interpretation based on machine and lesion type.

Algorithms↗
PubMed2005

Comparison of full-field digital mammography to screen-film mammography with respect to contrast and spatial resolution in tissue equivalent breast phantoms.

To determine if the improved contrast resolution of full-field digital mammography (FFDM) with reduced spatial resolution allows for superior or equal phantom object detection compared with screen-film mammography (SFM). Tissue equivalent breast phantoms simulating an adipose to glandular ratio of 50/50,30/70, and 20/80 were imaged according to each manufacturers' recommendation with four full-field digital mammography units (Fuji, Sectra, Fischer, and General Electric) and a screen-film mammography unit (MammoMatII 2000, Siemens, Munich, Germany). A total of 20 images were obtained in both hard- and soft-copy formats. For the purpose of soft-copy display, the screen-film hard-copy images were digitized with a 50 microm micron scanner. Six radiologists, experts in breast imaging, and three physicists, experts in scoring mammography phantoms, participated in a reader study where each reader scored each phantom for visibility of line-pairs and for 24 objects (fibers, clusters of specks, and masses). The data were recorded, entered into a database, and analyzed by a mixed-effect model. The limiting spatial resolution in line-pairs per millimeter visible with the digital units was less, regardless of display modality used, than that provided by the screen-film unit. The difference was statistically significant for the General Electric (p < 0.01) and Fuji digital mammography units (p = 0.03). With respect to the number of visible objects, a statistically significant higher number could be detected with the screen-film unit as compared to the Fischer (p < 0.01) and Sectra (p < 0.01) digital mammography units, but there was no significant difference between the other digital units and screen film. Overall, there was significantly better performance on the 50/50 phantom than with the 30/70 and 20/80 phantoms (p = 0.01, p < 0.01) for object visibility. For the digital mammography units, soft-copy display performed better than hard-copy display for the Fischer and Sectra images, but worse for Fuji and General Electric. In addition, soft-copy display of digitized screen-film images was significantly better than hard-copy display (p =0.02) of the original screen films for object visibility, but worse for spatial resolution. The higher contrast resolution of the FFDM units tested did not result in improved detection of line-pair resolution or objects in the phantoms tested versus screen-film mammography. The phantom performance of a digital mammography unit seems to be influenced by the type of detection task (line-pair resolution versus object visibility), the display modality (soft-copy versus hard-copy) chosen to score the phantoms, and the parenchymal pattern composition of the phantom.

Breast Neoplasms↗
PubMed2004

Factors affecting increasing radiation dose for mammography in North Carolina from 1997 through 2001: an analysis of Food and Drug Administration annual surveys.

RATIONALE AND OBJECTIVES: To determine which factors affected the increase in average glandular dose recorded at the annual US Food and Drug Administration Mammography Quality Standards Act inspections of mammography equipment in North Carolina from 1997 to 2001. MATERIALS AND METHODS: Average glandular dose, HVL, kVp, ambient light, luminance, equipment age, processing speed, and system speed for every mammography unit at all facilities in the state were collected by state inspectors. A mixed-effect model was used to assess the average changes of glandular dose over time and to identify the factors associated with these changes. RESULTS: There was a statistically significant increase in the average glandular dose in North Carolina in 1999, 2000, and 2001 when compared with the baseline year of 1997. Factors that were statistically significantly linked to this effect were changes in kVp, processing speed, and system speed. CONCLUSION: Average glandular dose for mammography has recently increased in North Carolina. This change is likely caused by changes in screen-film products and processing techniques.

Annual Reports as Topic↗
PubMed2004

The role of magnetic resonance imaging in diagnosis and management of breast cancer.

A review of the literature on the current applications of breast magnetic resonance imaging (MRI) indications, their rationale and their place in diagnosis and management of breast cancer was given. Contrast-enhanced breast MRI is developing as a valuable adjunct to mammography and sonography. Its high sensitivity for invasive breast cancer establishes its superiority in evaluation of multifocality/multicentricity, tumor response to neoadjuvant chemotherapy, detection of recurrence, and staging. Emerging applications include spectroscopy, usage of new contrast agents, and MRI-guided interventions, including noninvasive treatment of breast cancer. Its potential benefit in screening high-risk women has yet to be established with prospective studies, particularly with regard to false positive results.

Breast Neoplasms↗
PubMed2003

Ultrasound in the management of breast disease.

Since its introduction in the 1960s, ultrasound (US) has never been more important in breast disease management as it is today. Its historical role as an adjunct modality to mammography in differentiating cystic from solid lesions has been widely expanded. US-guided sampling procedures represent widely accepted modalities in lesion evaluation. Preoperative localization under US guidance is one of the methods of choice for nonpalpable solid lesions. Screening breast US is currently being investigated and might prove useful for high-risk women and women with dense breasts. Continuous technologic advances, such as high-frequency transducers, new Doppler-based techniques, microbubble contrast agents, harmonic and compound imaging, three-dimensional US, elasticity imaging, US detection of microcalcifications, perfusion US imaging, and computer-aided diagnosis all carry promise of further increases in US utility in the diagnosis and detection of breast disease.

Breast↗