Computer-aided detection of masses at mammography: interactive decision support versus prompts.

PURPOSE: To compare effectiveness of an interactive computer-aided detection (CAD) system, in which CAD marks and their associated suspiciousness scores remain hidden unless their location is queried by the reader, with the effect of traditional CAD prompts used in current clinical practice for the detection of malignant masses on full-field digital mammograms. MATERIALS AND METHODS: The requirement for institutional review board approval was waived for this retrospective observer study. Nine certified screening radiologists and three residents who were trained in breast imaging read 200 studies (63 studies containing at least one screen-detected mass, 17 false-negative studies, 20 false-positive studies, and 100 normal studies) twice, once with CAD prompts and once with interactive CAD. Localized findings were reported and scored by the readers. In the prompted mode, findings were recorded before and after activation of CAD. The partial area under the location receiver operating characteristic (ROC) curve for an interval of low false-positive fractions typical for screening, from 0 to 0.2, was computed for each reader and each mode. Differences in reader performance were analyzed by using software. RESULTS: The average partial area under the location ROC curve with unaided reading was 0.57, and it increased to 0.62 with interactive CAD, while it remained unaffected by prompts. The difference in reader performance for unaided reading versus interactive CAD was statistically significant (P = .009). CONCLUSION: When used as decision support, interactive use of CAD for malignant masses on mammograms may be more effective than the current use of CAD, which is aimed at the prevention of perceptual oversights.

Standalone computer-aided detection compared to radiologists' performance for the detection of mammographic masses.

OBJECTIVES: We developed a computer-aided detection (CAD) system aimed at decision support for detection of malignant masses and architectural distortions in mammograms. The effect of this system on radiologists' performance depends strongly on its standalone performance. The purpose of this study was to compare the standalone performance of this CAD system to that of radiologists. METHODS: In a retrospective study, nine certified screening radiologists and three residents read 200 digital screening mammograms without the use of CAD. Performances of the individual readers and of CAD were computed as the true-positive fraction (TPF) at a false-positive fraction of 0.05 and 0.2. Differences were analysed using an independent one-sample t-test. RESULTS: At a false-positive fraction of 0.05, the performance of CAD (TPF = 0.487) was similar to that of the certified screening radiologists (TPF = 0.518, P = 0.17). At a false-positive fraction of 0.2, CAD performance (TPF = 0.620) was significantly lower than the radiologist performance (TPF = 0.736, P <0.001). Compared to the residents, CAD performance was similar for all false-positive fractions. CONCLUSIONS: The sensitivity of CAD at a high specificity was comparable to that of human readers. These results show potential for CAD to be used as an independent reader in breast cancer screening.

Computer aided analysis of breast MRI enhancement kinetics using mean shift clustering and multifeature iterative region of interest selection.

PURPOSE: To evaluate automatic characterization of a breast MR lesion by its spatially coherent region of interest (ROI). MATERIALS AND METHODS: The method delineated 247 enhancing lesions using Otsu thresholding after manually placing a sphere. Mean Shift Clustering subdivided each volume, based on features including pharmacokinetic parameters. An iteratively trained classifier to predict the most suspicious ROI (IsR) was used, to predict the malignancy likelihood of each lesion. Performance was evaluated using receiver operator characteristic (ROC) analysis, and compared with a previous prototype. IsR was compared with noniterative training. The effect of adding BI-RADS™ morphology (from a radiologist) to the classifier was investigated. RESULTS: The area under the ROC curve (AUC) was 0.83 (95% confidence interval [CI] of 0.77-0.88), and was 0.75 (95%CI = 0.68-0.81; P = 0.029) without pharmacokinetic features. IsR performed better than conventional selection, based on one feature (AUC 0.75, 95%CI = 0.68-0.81; P = 0.035). With morphology, the AUC was 0.84 (95%CI = 0.78-0.88) versus 0.82 without (P = 0.40). CONCLUSION: Breast lesions can be characterized by their most suspicious, contiguous ROI using multi-feature clustering and iterative training. Characterization was improved by including pharmacokinetic modeling, while in our experiments, including morphology did not improve characterization.

MR-guided breast biopsy at 3T: diagnostic yield of large core needle biopsy compared with vacuum-assisted biopsy.

OBJECTIVE: The purpose of this study was to evaluate two MR-guided biopsy techniques at 3 T, large core needle breast biopsy (LCNB) and vacuum-assisted breast biopsy (VAB) and to compare the diagnostic yield and rate of complications to determine the optimal biopsy technique at 3 T. METHODS: 55 LCNB and 64 VAB were consecutively performed. Benign biopsy results were verified by retrospective correlation of histology, with pre-interventional, post-interventional MRI studies and follow-up and were classified as representative or non-representative. Time to follow-up was up to 2 years for the considered non-representative benign lesions. Statistical analysis was performed using the Chi-squared test. RESULTS: LCNB was technically successful in 100% of patients (55/55) and VAB in 98% of patients (63/64). Histopathological analysis resulted in 45 (82%) benign, 3 (5%) high-risk and 7 (13%) malignant lesions for LCNB and 43 (67%) benign, 3 (5%) high-risk and 18 (28%) malignant lesions. Distribution was significantly different (p < 0.001), favouring VAB over LCNB. CONCLUSION: Because of the substantially higher diagnostic yield and certainty of a benign diagnosis, VAB is the optimal biopsy technique at 3 T. LCNB should be considered when VAB is not feasible.

Comparison of enhancement characteristics between invasive lobular carcinoma and invasive ductal carcinoma.

PURPOSE: To compare enhancement characteristics between invasive lobular carcinoma (ILC) and invasive ductal carcinoma (IDC) on contrast enhanced MRI of the breast and to observe the magnitude of eventual differences as these may impair the diagnostic value of breast MRI in ILC. MATERIALS AND METHODS: We performed an analysis of enhancement characteristics on biphasic breast MRI in a series of 136 patients (103 IDC, 33 ILC) using an in-house developed application for pharmacokinetic modeling of contrast enhancement and a commercially available CAD application that evaluated the contrast-enhancement versus time curve. RESULTS: Pharmacokinetic analysis showed that the most enhancing voxels in IDC had significantly higher K(trans) -values than in ILC (P < 0.01). No difference in v(e) -values was noted between groups. Visual assessment of contrast-enhancement versus time curves revealed wash-out curves to be less common in ILC (48% versus 84%). However, when using the CAD-application to assess the most malignant looking curve, the difference was blotted out (76% versus 86%). CONCLUSION: ILC enhances slower than IDC but peak enhancement is not significantly less. The use of a CAD-application may help to determine the most malignant looking contrast-enhancement versus time curve, and hence facilitates lesion classification.

Value of ADC measurements for nodal staging after chemoradiation in locally advanced rectal cancer-a per lesion validation study.

OBJECTIVES: To evaluate the performance of diffusion-weighted MRI (DWI) in addition to T2-weighted (T2W) MRI for nodal restaging after chemoradiation in rectal cancer. METHODS: Thirty patients underwent chemoradiation followed by MRI (1.5 T) and surgery. Imaging consisted of T2W-MRI and DWI (b0, 500, 1000). On T2W-MRI, nodes were scored as benign/malignant by two independent readers (R1, R2). Mean apparent diffusion coefficient (ADC) was measured for each node. Diagnostic performance was compared for T2W-MRI, ADC and T2W+ADC, using a per lesion histological validation. RESULTS: ADC was higher for the malignant nodes (1.43 ± 0.38 vs 1.19 ± 0.27 *10⁻³ mm²/s, p < 0.001). Area under the ROC curve/sensitivity/specificity were 0.88/65%/93% (R1) and 0.95/71%/91% (R2) using T2W-MRI; 0.66/53%/82% using ADC (mean of two readers); and 0.91/56%/98% (R1) and 0.96/56%/99% (R2) using T2W+ADC. There was no significant difference between T2W-MRI and T2W+ADC. Interobserver reproducibility was good for T2W-MRI (κ0.73) and ADC (intraclass correlation coefficient 0.77). CONCLUSIONS: After chemoradiation, ADC measurements may have potential for nodal characterisation, but DWI on its own is not reliable. Addition of DWI to T2W-MRI does not improve accuracy and T2W-MRI is already sufficiently accurate.

Computer-aided detection in full-field digital mammography in a clinical population: performance of radiologist and technologists.

The purpose of the study was to evaluate the impact of a computer-aided detection (CAD) system on the performance of mammogram readers in interpreting digital mammograms in a clinical population. Furthermore, the ability of a CAD system to detect breast cancer in digital mammography was studied in comparison to the performance of radiologists and technologists as mammogram readers. Digital mammograms of 1,048 consecutive patients were evaluated by a radiologist and three technologists. Abnormalities were recorded and an imaging conclusion was given as a BI-RADS score before and after CAD analysis. Pathology results during 12 months follow up were used as a reference standard for breast cancer. Fifty-one malignancies were found in 50 patients. Sensitivity and specificity were computed before and after CAD analysis and provided with 95% CIs. In order to assess the detection rate of malignancies by CAD and the observers, the pathological locations of these 51 breast cancers were matched with the locations of the CAD marks and the mammographic locations that were considered to be suspicious by the observers. For all observers, the sensitivity rates did not change after application of CAD. A mean sensitivity of 92% was found for all technologists and 84% for the radiologist. For two technologists, the specificity decreased (from 84 to 83% and from 77 to 75%). For the radiologist and one technologist, the application of CAD did not have any impact on the specificity rates (95 and 83%, respectively). CAD detected 78% of all malignancies. Five malignancies were indicated by CAD without being noticed as suspicious by the observers. In conclusion, the results show that systematic application of CAD in a clinical patient population failed to improve the overall sensitivity of mammogram interpretation by the readers and was associated with an increase in false-positive results. However, CAD marked five malignancies that were missed by the different readers.

Assessment of false-negative cases of breast MR imaging in women with a familial or genetic predisposition.

In order to assess the characteristics of malignant breast lesions those were not detected during screening by MR imaging. In the Dutch MRI screening study(MRISC), a non-randomized prospective multicenter study,women with high familial risk or a genetic predisposition for breast cancer were screened once a year by mammography and MRI and every 6 months with a clinical breast examination (CBE). The false-negative MR examinations were subject of this study and were retrospectively reviewed by two experienced radiologists. From November 1999 until March 2006, 2,157 women were eligible for study analyses. Ninety-seven malignant breast tumors were detected, including 19 DCIS (20%). In 22 patients with a malignant lesion, the MRI was assessed as BI-RADS 1 or 2. One patient was excluded because the examinations were not available for review. Forty-three percent (9/21) of the false-negative MR cases concerned pure ductal carcinoma in situ (DCIS) or DCIS with invasive foci, in eight of them no enhancement was seen at the review. In six patients the features of malignancy were missed or misinterpreted.Small lesion size (n = 3), extensive diffuse contrast enhancement of the breast parenchyma (n = 2),and a technically inadequate examination (n = 1) were other causes of the missed diagnosis. A major part of the false-negative MR diagnoses concerned non-enhancing DCIS, underlining the necessity of screening not only with MRI but also with mammography. Improvement of MRI scanning protocols may increase the detection rate of DCIS. The missed and misinterpreted cases are reflecting the learning curve of a multicenter study.

Using computer-aided detection in mammography as a decision support.

OBJECTIVE: To evaluate an interactive computer-aided detection (CAD) system for reading mammograms to improve decision making. METHODS: A dedicated mammographic workstation has been developed in which readers can probe image locations for the presence of CAD information. If present, CAD findings are displayed with the computed malignancy rating. A reader study was conducted in which four screening radiologists and five non-radiologists participated to study the effect of this system on detection performance. The participants read 120 cases of which 40 cases had a malignant mass that was missed at the original screening. The readers read each mammogram both with and without CAD in separate sessions. Each reader reported localized findings and assigned a malignancy score per finding. Mean sensitivity was computed in an interval of false-positive fractions less than 10%. RESULTS: Mean sensitivity was 25.1% in the sessions without CAD and 34.8% in the CAD-assisted sessions. The increase in detection performance was significant (p = 0.012). Average reading time was 84.7 ± 61.5 s/case in the unaided sessions and was not significantly higher when interactive CAD was used (85.9 ± 57.8 s/case). CONCLUSION: Interactive use of CAD in mammography may be more effective than traditional CAD for improving mass detection without affecting reading time.

Has the liver and other visceral organs migrated to its normal position in children with giant omphalocele? A follow-up study with ultrasonography.

UNLABELLED: This study evaluates whether, on the long run, in patients born with a giant omphalocele, the liver and other solid organs reach their normal position, shape, and size. Seventeen former patients with a giant omphalocele, treated between 1970 and 2004, were included. Physical examination was supplemented with ultrasonography for ventral hernia and precise description of the liver, spleen, and kidneys. The findings were compared with 17 controls matched for age, gender, and body mass index. We found an abnormal position of the liver, spleen, left kidney, and right kidney in eight, six, five, and four patients, respectively. An unprotected liver was present in all 17 patients and in 11 controls, the difference being statistically significant (p = 0.04). In ten of the 11 patients with an incisional hernia, the liver was located underneath the abdominal defect. CONCLUSION: In all former patients with a giant omphalocele, an abnormal position of the liver and in the majority of them, an incisional hernia was also found. The liver and sometimes also the spleen and the kidneys do not migrate to their normal position. Exact documentation and good information are important for both the patient and their caretakers in order to avoid liver trauma.

Magnetic resonance imaging in size assessment of invasive breast carcinoma with an extensive intraductal component.

BACKGROUND: Breast-conserving treatment of invasive breast carcinoma with an extensive intraductal component (EIC) is associated with DCIS-involved surgical margins and therefore it has an increased recurrence rate. EIC is a non-palpable lesion of which the size is frequently underestimated on mammography. This study was undertaken to evaluate the accuracy of MRI in size assessment of breast cancer with EIC. METHODS: 23 patients were identified and the mammographic (n = 21) and MR (n = 23) images were re-reviewed by a senior radiologist. Size on MR images was compared with histopathological tumour extent. RESULTS: The correlation of radiological size with histopathological size was r = 0.20 in mammography (p = 0.39) compared to r = 0.65 in MRI (p < 0.01). Mammography underestimated histopathological tumour size in 62%. MR images over- or underestimated tumour size in 22% and 30% of the cases, respectively. In poorly differentiated EIC, MRI adequately estimated the extent more often compared to moderately differentiated EIC (60% versus 25%, respectively). CONCLUSION: Size assessment of MRI imaging was more accurate compared to mammography. This was predominantly true for poorly differentiated EIC.

MRI compared to conventional diagnostic work-up in the detection and evaluation of invasive lobular carcinoma of the breast: a review of existing literature.

PURPOSE: The clinical diagnosis and management of invasive lobular carcinoma (ILC) of the breast presents difficulties. Magnetic resonance imaging (MRI) has been proposed as the imaging modality of choice for the evaluation of ILC. Small studies addressing different aspects of MRI in ILC have been presented but no large series to date. To address the usefulness of MRI in the work-up of ILC, we performed a review of the currently published literature. MATERIALS AND METHODS: We performed a literature search using the query "lobular AND (MRI OR MR OR MRT OR magnetic)" in the Cochrane library, PubMed and scholar.google.com, to retrieve all articles that dealt with the use of MRI in patients with ILC. We addressed sensitivity, morphologic appearance, correlation with pathology, detection of additional lesions, and impact of MRI on surgery as different endpoints. Whenever possible we performed meta-analysis of the pooled data. RESULTS: Sensitivity is 93.3% and equal to overall sensitivity of MRI for malignancy in the breast. Morphologic appearance is highly heterogeneous and probably heavily influenced by interreader variability. Correlation with pathology ranges from 0.81 to 0.97; overestimation of lesion size occurs but is rare. In 32% of patients, additional ipsilateral lesions are detected and in 7% contralateral lesions are only detected by MRI. Consequently, MRI induces change in surgical management in 28.3% of cases. CONCLUSION: This analysis indicates MRI to be valuable in the work-up of ILC. It provides additional knowledge that cannot be obtained by conventional imaging modalities which can be helpful in patient treatment.

Efficacy of MRI and mammography for breast-cancer screening in women with a familial or genetic predisposition.

BACKGROUND: The value of regular surveillance for breast cancer in women with a genetic or familial predisposition to breast cancer is currently unproven. We compared the efficacy of magnetic resonance imaging (MRI) with that of mammography for screening in this group of high-risk women. METHODS: Women who had a cumulative lifetime risk of breast cancer of 15 percent or more were screened every six months with a clinical breast examination and once a year by mammography and MRI, with independent readings. The characteristics of the cancers that were detected were compared with the characteristics of those in two different age-matched control groups. RESULTS: We screened 1909 eligible women, including 358 carriers of germ-line mutations. Within a median follow-up period of 2.9 years, 51 tumors (44 invasive cancers, 6 ductal carcinomas in situ, and 1 lymphoma) and 1 lobular carcinoma in situ were detected. The sensitivity of clinical breast examination, mammography, and MRI for detecting invasive breast cancer was 17.9 percent, 33.3 percent, and 79.5 percent, respectively, and the specificity was 98.1 percent, 95.0 percent, and 89.8 percent, respectively. The overall discriminating capacity of MRI was significantly better than that of mammography (P<0.05). The proportion of invasive tumors that were 10 mm or less in diameter was significantly greater in our surveillance group (43.2 percent) than in either control group (14.0 percent [P<0.001] and 12.5 percent [P=0.04], respectively). The combined incidence of positive axillary nodes and micrometastases in invasive cancers in our study was 21.4 percent, as compared with 52.4 percent (P<0.001) and 56.4 percent (P=0.001) in the two control groups. CONCLUSIONS: MRI appears to be more sensitive than mammography in detecting tumors in women with an inherited susceptibility to breast cancer.

Volumetric breast density estimation from full-field digital mammograms.

A method is presented for estimation of dense breast tissue volume from mammograms obtained with full-field digital mammography (FFDM). The thickness of dense tissue mapping to a pixel is determined by using a physical model of image acquisition. This model is based on the assumption that the breast is composed of two types of tissue, fat and parenchyma. Effective linear attenuation coefficients of these tissues are derived from empirical data as a function of tube voltage (kVp), anode material, filtration, and compressed breast thickness. By employing these, tissue composition at a given pixel is computed after performing breast thickness compensation, using a reference value for fatty tissue determined by the maximum pixel value in the breast tissue projection. Validation has been performed using 22 FFDM cases acquired with a GE Senographe 2000D by comparing the volume estimates with volumes obtained by semi-automatic segmentation of breast magnetic resonance imaging (MRI) data. The correlation between MRI and mammography volumes was 0.94 on a per image basis and 0.97 on a per patient basis. Using the dense tissue volumes from MRI data as the gold standard, the average relative error of the volume estimates was 13.6%.

The value of magnetic resonance imaging in diagnosis and size assessment of in situ and small invasive breast carcinoma.

BACKGROUND: The value of magnetic resonance imaging (MRI) in diagnosis and size assessment of ductal carcinoma-in-situ (DCIS) and DCIS with small (<10 mm) invasive carcinoma was evaluated. METHODS: Fifty-four patients with DCIS and 12 patients with DCIS and small invasive carcinoma were included. Mammographic (N = 64) and MRI (N = 22) images were retrospectively reviewed. Correlation coefficients were calculated to assess differences in size between imaging and histopathologic examination. RESULTS: Mammographic rate of detection for DCIS was 48/52 (92%) and for DCIS with small invasive carcinoma, 10/12 (83%). MRI revealed 1 false negative case and the rate of detection for DCIS was 16/17 (94%). Correlation of mammographic size with histopathologic size was r = .44 (P < .01) and r = 0.49 (P = .03) for MRI. Mammography underestimated lesion size by 5 mm or more in 47%, whereas with MRI size was adequately assessed in 43% and overestimated in 38%. CONCLUSIONS: DCIS can be visualised on MRI with high sensitivity, although tumor size can be overestimated.

MRI-guided preoperative wire localization of nonpalpable breast lesions.

With the increasing use of magnetic resonance imaging (MRI), the physician is more frequently confronted with nonpalpable breast lesions that are only visible on MRI. In these cases, it is often difficult to obtain adequate material for pathological examination. One of the methods that may be performed is excisional biopsy after MRI-guided wire localization. This study intends to examine the feasibility and added benefit of this method. It appears to be a reliable and useful tool that is, therefore, of additional benefit to surgical practice.

Hereditary breast cancer growth rates and its impact on screening policy.

Imaging is often performed yearly for the surveillance of BRCA1/2 mutation carriers and women at high familial breast cancer risk. Growth of cancers in carriers may be faster as these tumours are predominantly high grade. Quantitative data on tumour growth rates in these 2 groups are lacking. Here, we have examined 80 high-risk women under surveillance for tumour size at diagnosis and preceding examinations at mammography and/or MRI. Tumour volume doubling time (DT) was assessed in 30 cancers in BRCA1/2 mutation carriers and 25 non-carriers. Impact of age and menopausal status were also evaluated. Mean DT of all invasive cancers was shorter in carriers (45 days CI: 26-73) than non-carriers (84 days CI: 58-131) (P = 0.048). Mean age at diagnosis was lower in carriers (40 years) than non-carriers (45 years) (P = 0.007). At multivariable analysis only age (P = 0.03), not risk-group (P = 0.26) nor menopause (P = 0.58) correlated significantly with DT. The mean growth rate slowed down to half in each successive 10 years-older group. In conclusion, age at detection indicated the growth rates of hereditary and familial breast cancers. It is recommended that the screening frequency should be adjusted according to a woman's age and a high-sensitive biannual test may be appropriate before the age of 40 years.

Variability in the description of morphologic and contrast enhancement characteristics of breast lesions on magnetic resonance imaging.

RATIONALE AND OBJECTIVE: The objective of this study was to evaluate the interobserver variability in reporting descriptive kinetic and morphologic enhancement features at breast magnetic resonance imaging. MATERIALS AND METHODS: Four observers evaluated 103 lesions, 49 malignant and 54 benign, proven by histopathology. They used standardized terminology with the following characteristics: "early enhancement kinetics" and "late enhancement kinetics" in curves from both reader-determined and preset regions of interest (ROIs), "enhancement pattern," "shape," "margin," "internal enhancement," and a final assessment score. Agreement was calculated using the kappa statistic. Differences in agreement were calculated using Fisher exact test. RESULTS: kappa was 0.27 for both early and late enhancement; preset ROIs improved kappa to 0.47 and 0.67, respectively (odds ratios, 1.7 and 4.5). kappa was 0.45 for pattern, 0.42 for shape, 0.26 for margin, 0.25 for internal enhancement, and 0.28 for final assessment. CONCLUSIONS: There was considerable variability in the use of most generally accepted terms. The preparation of ROIs was a major source of variability in the interpretation of enhancement curves.

Magnetic resonance-guided biopsies and localizations of the breast: initial experiences using an open breast coil and compatible intervention device.

OBJECTIVE: The objective of this study was to evaluate the performance of a new commercially available open breast coil and compatible intervention device (Machnet) for magnetic resonance image (MRI)-guided breast interventions. MATERIALS AND METHODS: Breast lesions detected on MRI were evaluated using MRI-guided core biopsy (n = 20) and/or preoperative wire localization (n = 23) on histologic outcome and accuracy of localization. Time needed to perform a procedure and occurring problems were recorded. RESULTS: Mean lesion size was <10 mm. Two of 20 lesions could not be biopsied because they were out of range for the device. Biopsies were conclusive in half of the cases; most lesions missed were <10 mm. The average accuracy for needle placement in the localization procedures was less than 2 mm (range, 0-5 mm). The average procedure time was 40 minutes for a biopsy procedure and 33 minutes for an MRI-guided localization. CONCLUSIONS: Preoperative MRI-guided localizations can be performed quickly and accurately. However, in MRI-guided core biopsies, especially in small lesions, the device does not guarantee conclusive histologic evaluation of the lesion targeted.

A unique case of PHACES syndrome confirming the assumption that PHACES syndrome and the sternal malformation-vascular dysplasia association are part of the same spectrum of malformations.

PHACES is an acronym for a rare neurocutaneous disorder including the following features: posterior fossa brain malformations; facial hemangiomas; arterial, cardiac, and eye anomalies; and sternal clefts and/or supraumbilical abdominal raphe. Facial hemangiomas are the hallmark of this syndrome. We report a patient with facial hemangiomas, sternal clefting and carotid abnormalities. She is another example of the combined existence of sternal clefting and carotid abnormalities in PHACES syndrome and even more unique since she does not have an aortic abnormality. This report emphasizes that many different combinations of features may be seen in PHACES syndrome.