Soy isoflavones decrease fibroglandular breast tissue measured by magnetic resonance imaging in premenopausal women: A 2-year randomized double-blind placebo controlled clinical trial.

BACKGROUND & AIMS: Populations consuming soy have reduced risk for breast cancer, but the mechanisms are unclear. We tested the hypothesis that soy isoflavones, which have ovarian hormone-like effects, can reduce fibroglandular breast tissue (FGBT, 'breast density'), a strong risk marker for breast cancer. METHODS: Premenopausal women (age 30-42 years) were randomized to consume isoflavones (136.6 mg as aglycone equivalents, n = 99) or placebo (n = 98) for 5 days per week up to 2 years, and changes in breast composition measured by magnetic resonance imaging at baseline and yearly intervals were compared after square root transformation using linear mixed effects regression models. RESULTS: By intention-to-treat analyses (n = 194), regression coefficients (ß estimates) of the interaction of time and isoflavone treatment were -0.238 (P = 0.06) and -0.258 (P < 0.05) before and after BMI adjustment, respectively for FGBT, 0.620 (P < 0.05) and 0.248 (P = 0.160), respectively for fatty breast tissue (FBT), and -0.155 (P < 0.05) and -0.107 (P < 0.05), respectively for FGBT as percent of total breast (FGBT%). ß Estimates for interaction of treatment with serum calcium were -2.705 for FBT, and 0.588 for FGBT% (P < 0.05, before but not after BMI adjustment). BMI (not transformed) was related to the interaction of treatment with time (ß = 0.298) or with calcium (ß = -1.248) (P < 0.05). Urinary excretion of isoflavones in adherent subjects (n = 135) significantly predicted these changes in breast composition. Based on the modeling results, after an average of 1.2, 2.2 and 3.3 years of supplementation, a mean decrease of FGBT by 5.3, 12.1, and 19.3 cc, respectively, and a mean decrease of FGBT% by 1.37, 2.43, and 3.50%, respectively, were estimated for isoflavone exposure compared to placebo treatment. Subjects with maximum isoflavone excretion were estimated to have 38 cc less FGBT (or ∼3.13% less FGBT%) than subjects without isoflavone excretion. Decrease in FGBT and FGBT% was more precise with daidzein than genistein. CONCLUSIONS: Soy isoflavones can induce a time- and concentration-dependent decrease in FGBT, a biomarker for breast cancer risk, in premenopausal women, and moderate effects of calcium on BMI and breast fat, suggesting a beneficial effect of soy consumption. TRIAL REGISTRATION: www. CLINICALTRIALS: gov identifier: NCT00204490. TRIAL REGISTRATION: www. CLINICALTRIALS: gov identifier: NCT00204490.

Medical physics 3.0 versus 1.0: A case study in digital radiography quality control.

PURPOSE: The study illustrates how a renewed approach to medical physics, Medical Physics 3.0 (MP3.0), can identify performance decrement of digital radiography (DR) systems when conventional Medical Physics 1.0 (MP1.0) methods fail. METHODS: MP1.0 tests included traditional annual tests plus the manufacturer's automated Quality Assurance Procedures (QAP) of a DR system before and after a radiologist's image quality (IQ) complaint repeated after service intervention. Further analysis was conducted using nontraditional MP3.0 tests including longitudinal review of QAP results from a 15-yr database, exposure-dependent signal-to-noise (SNR2 ), clinical IQ, and correlation with the institutional service database. Clinical images were analyzed in terms of IQ metrics by the Duke University Clinical Imaging Physics Group using previously validated software. RESULTS: Traditional metrics did not indicate discrepant system performance at any time. QAP reported a decrease in contrast-to-noise ratio (CNR) after detector replacement, but remained above the manufacturer's action limit. Clinical images showed increased lung noise (Ln), mediastinum noise (Mn), and subdiaphragm-lung contrast (SLc), and decreased lung gray level (Lgl) following detector replacement. After detector recalibration, QAP CNR improved, but did not return to previous levels. Lgl and SLc no longer significantly differed from before detector recalibration; however, Ln and Mn remained significantly different. Exposure-dependent SNR2 documented the detector operating within acceptable limits 9 yr previously but subsequently becoming miscalibrated sometime before four prior annual tests. Service records revealed catastrophic failure of the computer containing the original detector calibration from 11 yr prior. It is likely that the incorrect calibration backup file was uploaded at that time. CONCLUSIONS: MP1.0 tests failed to detect substandard system performance, but MP3.0 methods determined the root cause of the problem. MP3.0 exploits the wealth of data with more sensitive performance indicators. Data analytics are powerful tools whose proper application could facilitate early intervention in degraded system performance.

Automated quality control assessment of clinical chest images.

PURPOSE: The purpose of this study was to determine whether a proposed suite of objective image quality metrics for digital chest radiographs is useful for monitoring image quality in a clinical setting unique from the one where the metrics were developed. METHODS: Seventeen gridless AP chest radiographs from a GE Optima portable digital radiography (DR) unit ("sub-standard" images; Group 2) and 17 digital PA chest radiographs ("standard-of-care" images; Group 1) and 15 gridless (non-routine) PA chest radiographs (images with a gross technical error; Group 3) from a Discovery DR unit were chosen for analysis. Group 2 images were acquired with a lower kVp (100 vs 125) and shorter source-to-image distance (127 cm vs 183 cm) and were expected to have lower quality than Group 1 images. Group 3 images were expected to have degraded contrast vs Group 1 images. Images were anonymized and securely transferred to the Duke University Clinical Imaging Physics Group for analysis using software described and validated previously. Individual image quality was reported in terms of lung gray level, lung detail, lung noise, rib-lung contrast, rib sharpness, mediastinum detail, mediastinum noise, mediastinum alignment, subdiaphragm-lung contrast, and subdiaphragm area. Metrics were compared across groups. To improve precision of means and confidence intervals for routine exams, an additional 66 PA images were acquired, processed, and pooled with Group 1. Three observer studies were conducted to assess whether humans were able to identify images classified by the algorithm as abnormal. RESULTS: Metrics agreed with published Quality Consistency Ranges with three exceptions: higher lung gray level, lower rib-lung contrast, and lower subdiaphragm-lung contrast. Higher (stored) bit depth (14 vs 12) accounted for higher lung gray level values in our images. Values were most internally consistent for Group 1. The most sensitive metric for distinguishing between groups was mediastinum noise, followed closely by lung noise. The least sensitive metrics were mediastinum detail and rib-lung contrast. The algorithm was more sensitive than human observers at detecting suboptimal diagnostic quality images. CONCLUSIONS: The software appears promising for objectively and automatically identifying suboptimal images in a clinical imaging operation. The results can be used to establish local quality consistency ranges and action limits per facility preferences.

Evaluation of cassette-based digital radiography detectors using standardized image quality metrics: AAPM TG-150 Draft Image Detector Tests.

The purpose of this study was to evaluate several of the standardized image quality metrics proposed by the American Association of Physics in Medicine (AAPM) Task Group 150. The task group suggested region-of-interest (ROI)-based techniques to measure nonuniformity, minimum signal-to-noise ratio (SNR), number of anomalous pixels, and modulation transfer function (MTF). This study evaluated the effects of ROI size and layout on the image metrics by using four different ROI sets, assessed result uncertainty by repeating measurements, and compared results with two commercially available quality control tools, namely the Carestream DIRECTVIEW Total Quality Tool (TQT) and the GE Healthcare Quality Assurance Process (QAP). Seven Carestream DRX-1C (CsI) detectors on mobile DR systems and four GE FlashPad detectors in radiographic rooms were tested. Images were analyzed using MATLAB software that had been previously validated and reported. Our values for signal and SNR nonuniformity and MTF agree with values published by other investigators. Our results show that ROI size affects nonuniformity and minimum SNR measurements, but not detection of anomalous pixels. Exposure geometry affects all tested image metrics except for the MTF. TG-150 metrics in general agree with the TQT, but agree with the QAP only for local and global signal nonuniformity. The difference in SNR nonuniformity and MTF values between the TG-150 and QAP may be explained by differences in the calculation of noise and acquisition beam quality, respectively. TG-150's SNR nonuniformity metrics are also more sensitive to detector nonuniformity compared to the QAP. Our results suggest that fixed ROI size should be used for consistency because nonuniformity metrics depend on ROI size. Ideally, detector tests should be performed at the exact calibration position. If not feasible, a baseline should be established from the mean of several repeated measurements. Our study indicates that the TG-150 tests can be used as an independent standardized procedure for detector performance assessment.

Comparison of breast tissue measurements using magnetic resonance imaging, digital mammography and a mathematical algorithm.

Women with mostly mammographically dense fibroglandular tissue (breast density, BD) have a four- to six-fold increased risk for breast cancer compared to women with little BD. BD is most frequently estimated from two-dimensional (2D) views of mammograms by a histogram segmentation approach (HSM) and more recently by a mathematical algorithm consisting of mammographic imaging parameters (MATH). Two non-invasive clinical magnetic resonance imaging (MRI) protocols: 3D gradient-echo (3DGRE) and short tau inversion recovery (STIR) were modified for 3D volumetric reconstruction of the breast for measuring fatty and fibroglandular tissue volumes by a Gaussian-distribution curve-fitting algorithm. Replicate breast exams (N = 2 to 7 replicates in six women) by 3DGRE and STIR were highly reproducible for all tissue-volume estimates (coefficients of variation <5%). Reliability studies compared measurements from four methods, 3DGRE, STIR, HSM, and MATH (N = 95 women) by linear regression and intra-class correlation (ICC) analyses. Rsqr, regression slopes, and ICC, respectively, were (1) 0.76-0.86, 0.8-1.1, and 0.87-0.92 for %-gland tissue, (2) 0.72-0.82, 0.64-0.96, and 0.77-0.91, for glandular volume, (3) 0.87-0.98, 0.94-1.07, and 0.89-0.99, for fat volume, and (4) 0.89-0.98, 0.94-1.00, and 0.89-0.98, for total breast volume. For all values estimated, the correlation was stronger for comparisons between the two MRI than between each MRI versus mammography, and between each MRI versus MATH data than between each MRI versus HSM data. All ICC values were >0.75 indicating that all four methods were reliable for measuring BD and that the mathematical algorithm and the two complimentary non-invasive MRI protocols could objectively and reliably estimate different types of breast tissues.

MR imaging in the triage of pregnant patients with acute abdominal and pelvic pain.

PURPOSE: To retrospectively assess the performance of MR imaging in the evaluation and triage of pregnant patients presenting with acute abdominal or pelvic pain. METHOD AND MATERIALS: MRI studies of pregnant patients who were referred for acute abdominal pain between 2001 and 2007 were included. MR images were retrospectively reviewed and compared with surgical and pathologic findings and clinical follow-up data. Analysis of imaging findings included evaluation of the visceral organs, bowel and mesentery, appendix (for presence of appendicitis), ovaries (detection and adnexal masses were evaluated), focal inflammation, presence of abscesses, and any other abnormal findings. RESULTS: A total of 118 pregnant patients were included. MR findings were inconclusive in 2 patients and were positive for acute appendicitis in 11 patients (n = 9 confirmed by surgery, n = 2 improved without surgery). One patient with inconclusive MR had surgically confirmed appendicitis; the other patient with inconclusive MR had surgically confirmed adnexal torsion. Other surgical/interventional diagnoses suggested by MR imaging were adnexal torsion (n = 4), abscess (n = 4), acute cholecystitis (n = 1), and gastric volvulus (n = 1). Two patients with MR diagnosis of torsion improved without surgery. One patient with MR diagnosis of abscess had biliary cystadenoma at surgery. The rest of the MR diagnoses above were confirmed surgically or interventionally. MR imaging was normal in 67 patients and demonstrated medically treatable etiology in 28 patients: adnexal lesions (n = 9), urinary pathology (n = 6), cholelithiasis (n = 4), degenerating fibroid (n = 3), DVT (n = 2), hernia (n = 1), colitis (n = 1), thick terminal ileum (n = 1), rectus hematoma (n = 1). Three of these patients had negative surgical exploration and one had adnexal mass excision during pregnancy. Other patients were discharged with medical treatment. The sensitivity, specificity, accuracy, positive predictive values (ppv), and negative predictive values (npv) of MR imaging for acute appendicitis, and surgical/ interventional diagnoses were 90.0% vs. 88.9%, 98.1% vs. 95.0%, 97.5% vs. 94.1%, 81.8% vs. 76.2%, 99.1% vs. 97.9%, respectively. CONCLUSION: MR imaging is an excellent modality for diagnosis of acute appendicitis and exclusion of diseases requiring surgical/interventional treatment. Therefore MR imaging is useful for triage of pregnant patients with acute abdominal and pelvic pain.

Computing mammographic density from a multiple regression model constructed with image-acquisition parameters from a full-field digital mammographic unit.

Breast density (the percentage of fibroglandular tissue in the breast) has been suggested to be a useful surrogate marker for breast cancer risk. It is conventionally measured using screen-film mammographic images by a labor-intensive histogram segmentation method (HSM). We have adapted and modified the HSM for measuring breast density from raw digital mammograms acquired by full-field digital mammography. Multiple regression model analyses showed that many of the instrument parameters for acquiring the screening mammograms (e.g. breast compression thickness, radiological thickness, radiation dose, compression force, etc) and image pixel intensity statistics of the imaged breasts were strong predictors of the observed threshold values (model R(2) = 0.93) and %-density (R(2) = 0.84). The intra-class correlation coefficient of the %-density for duplicate images was estimated to be 0.80, using the regression model-derived threshold values, and 0.94 if estimated directly from the parameter estimates of the %-density prediction regression model. Therefore, with additional research, these mathematical models could be used to compute breast density objectively, automatically bypassing the HSM step, and could greatly facilitate breast cancer research studies.

Evaluation of three-dimensional computed tomography processing for deep inferior epigastric perforator flap breast reconstruction.

BACKGROUND: The deep inferior epigastric perforator flap procedure has become a popular alternative for women who require breast reconstruction. One of the difficulties with this procedure is identifying perforator arteries large enough to ensure that the harvested tissue is well vascularized. Current techniques involve imaging the perforator arteries with computed tomography (CT) to produce a grid mapping the locations of the perforator arteries relative to the umbilicus. OBJECTIVES: To compare the time it takes to produce a map of the perforators using either two-dimensional (2D) or three-dimensional (3D) CT, and to see whether there is a benefit in using a 3D model. METHODS: Patient CT abdomen and pelvis scans were acquired from a GE 64-slice scanner. CT image processing was performed with the GE 3D Advantage Workstation v4.2 software. Maps of the perforators were generated both as 2D and 3D representations. Perforators within a region 5 cm rostral and 7 cm caudal to the umbilicus were measured and the times to perform these measurements using both 2D and 3D images were recorded by a stopwatch. RESULTS: Although the 3D method took longer than the 2D method (mean [+/- SD] time 1:51+/-0:35 min versus 1:08+/-0:16 min per perforator artery, respectively), producing a 3D image provides much more information than the 2D images alone. Additionally, an actual-sized 3D image can be printed out, removing the need to make measurements and producing a grid. CONCLUSIONS: Although it took less time to create a grid of the perforators using 2D axial CT scans, the 3D reconstruction of the abdomen allows the plastic surgeons to better visualize the patient's anatomy and has definite clinical utility.

Localization of appendix with MDCT and influence of findings on choice of appendectomy incision.

OBJECTIVE: The purpose of this study was to show the relation between McBurney's point and the appendix in patients undergoing 3D MDCT and to investigate the effect of this information on a surgeon's choice of appendectomy incision. MATERIAL AND METHODS: Among 142 adults undergoing consecutive MDCT studies, 100 patients (35 women, 65 men; mean age, 52.1 years) with an identifiable appendix on abdominopelvic MDCT examinations were selected for the study group. The presence of intraabdominal mass or a history of abdominal surgery were the exclusion criteria. Three-dimensional reconstruction of the CT data was performed with a surface shaded display algorithm. The locations of the base of the appendix and McBurney's point were marked on a single 3D image that allowed display of the skin surface markings for each patient. The superoinferior and mediolateral distances from the level of the appendix to the level of McBurney's point were measured, and the radial distance was calculated from these measurements. A surgeon experienced in emergency abdominal surgery reviewed 3D CT images and one axial image showing the appendix, and his choice of incision for each patient based on the CT information was recorded. The influence of the superoinferior and mediolateral distances of the appendix from McBurney's point on the surgeon's decision was analyzed with a multivariate logistic regression model. RESULTS: The appendix was exactly at McBurney's point in only 4% of the patients. In 36% of the cases, the appendix was within 3 cm, in 28% of cases it was 3-5 cm, and in 36% of the cases it was more than 5 cm away from McBurney's point. Mean +/- SD superoinferior, mediolateral, and radial distances between the appendix and McBurney's point were 33.0 +/- 24.1, 20.8 +/- 19.3, and 42.1 +/- 26.7 mm, respectively. After reviewing the images, the surgeon would have altered his incision site in 35% of the cases. The surgeon preferred a higher incision in 28% and a lower incision in 7% of the cases. Both positive and negative superoinferior displacement away from McBurney's point were significant factors regarding the surgeon's decision to alter the incision (p = 0.005), and the superoinferior distance was more than 3 cm in 94% of the cases in which the surgeon would have altered the incision. CONCLUSION: The location of the appendix varies widely among individuals, and McBurney's point has limitations as an anatomic landmark. Three-dimensional MDCT findings can be useful to surgeons customizing appendectomy incisions. Additional information about the location of the appendix in the CT report (if possible, together with a 3D image showing the location of the appendix) may be beneficial for surgeons performing appendectomy.

Thickness of molybdenum filter and squared contrast-to-noise ratio per dose for digital mammography.

OBJECTIVE: The objective of our study was to test whether the lesion-tissue contrast-to-noise ratio (CNR) at a given dose level can be improved by increasing the thickness of the molybdenum (Mo) filter currently used in digital mammography. MATERIALS AND METHODS: We studied how the CNR between breast and a 5-mm simulated infiltrating ductal carcinoma (IDC) embedded in a 5-cm-thick breast changes with Mo filter thickness. We performed phantom imaging experiments by modifying the filter wheel of a Senographe 2000D unit with Mo filters that ranged from 15 to 90 microm in thickness. A 5-cm-thick 50% glandular-50% adipose breast phantom with a 5-mm insert simulating IDC was used as the phantom for all the cases. The CNRs between the breast phantom and the IDC insert were measured, and average glandular doses were calculated using a filtration-dependent X-ray spectra model and a breast dosimetry model based on a validated Monte Carlo simulation. RESULTS: The lesion-tissue CNR at a given dose level increases with increasing Mo filter thickness from 15 to 90 microm. The measured squared CNR per dose increased by 8%, 14%, 17%, and 17% for 45-, 60-, 75-, and 90-microm Mo filters, respectively, compared with the standard 30-microm Mo filter. Meanwhile, the exposure times were increased by 35% (45 microm), 71% (60 microm), 177% (75 microm), and 229% (90 microm). CONCLUSION: Increasing Mo filter thickness from 30 to 60 microm can increase lesion-tissue squared CNR per dose by 14% with a tolerable increase in the duration of exposure.