Comparison of gadobenate dimeglumine-enhanced breast MRI and gadopentetate dimeglumine-enhanced breast MRI with mammography and ultrasound for the detection of breast cancer.

PURPOSE: To compare gadobenate dimeglumine-enhanced magnetic resonance imaging (MRI) with gadopentetate dimeglumine-enhanced MRI, mammography, and ultrasound for breast cancer detection across different malignant lesion types and across different densities of breast tissue. MATERIALS AND METHODS: In all, 153 women with Breast Imaging Reporting and Data System (BI-RADS) 3­5 findings on mammography and/or ultrasound underwent identical breast MRI exams at 1.5T with gadobenate dimeglumine and gadopentetate dimeglumine. Images were evaluated by three independent blinded radiologists. Mammography, ultrasound, and combined mammography and/or ultrasound findings were available for 108, 109, and 131 women. Imaging findings were matched with histology data by a fourth, independent, blinded radiologist. Malignant lesion detection rates and diagnostic performance were compared. RESULTS: In all, 120, 120, and 140 confirmed malignant lesions were present in patients undergoing MRI+mammography, MRI+ultrasound, and MRI+mammography and/or ultrasound, respectively. Significantly greater cancer detection rates were noted by all three readers for comparisons of gadobenate dimeglumine-enhanced MRI with mammography (Δ15.8­17.5%; P < 0.0001), ultrasound (Δ18.3­20.0%; P < 0.0001), and mammography and/or ultrasound (Δ8.6­10.7%; P ≤ 0.0105) but not for comparisons of gadopentetate dimeglumine-enhanced MRI with conventional techniques (P > 0.05). The false-positive detection rates were lower on gadobenate dimeglumine-enhanced MRI than on conventional imaging (4.0­5.5% vs. 11.1% at mammography; 6.3­8.4% vs. 15.5% at ultrasound). Significantly improved cancer detection on MRI was noted in heterogeneously dense breast (91.2­97.3% on gadobenate dimeglumine-enhanced MRI vs. 77.2­84.9% on gadopentetate dimeglumine-enhanced MRI vs. 71.9-84.9% with conventional techniques) and for invasive cancers (93.2­96.2% for invasive ductal carcinoma [IDC] on gadobenate dimeglumine-enhanced MRI vs. 79.7­88.5% on gadopentetate dimeglumine-enhanced MRI vs. 77.0­84.4% with conventional techniques). Overall diagnostic performance for the detection of cancer was superior on gadobenate dimeglumine-enhanced MRI than on conventional imaging or gadopentetate dimeglumine-enhanced MRI. CONCLUSION: Gadobenate dimeglumine-enhanced MRI significantly improves cancer detection compared to gadopentetate dimeglumine-enhanced MRI, mammography, and ultrasound in a selected group of patients undergoing breast MRI for preoperative staging or because of inconclusive findings at conventional imaging.

Measurement of tumour size with mammography, sonography and magnetic resonance imaging as compared to histological tumour size in primary breast cancer.

BACKGROUND: Tumour size in breast cancer influences therapeutic decisions. The purpose of this study was to evaluate sizing of primary breast cancer using mammography, sonography and magnetic resonance imaging (MRI) and thereby establish which imaging method most accurately corresponds with the size of the histological result. METHODS: Data from 121 patients with primary breast cancer were analysed in a retrospective study. The results were divided into the groups "ductal carcinoma in situ (DCIS)", invasive ductal carcinoma (IDC) + ductal carcinoma in situ (DCIS)", "invasive ductal carcinoma (IDC)", "invasive lobular carcinoma (ILC)" and "other tumours" (tubular, medullary, mucinous and papillary breast cancer). The largest tumour diameter was chosen as the sizing reference in each case. Bland-Altman analysis was used to determine to what extent the imaging tumour size correlated with the histopathological tumour sizes. RESULTS: Tumour size was found to be significantly underestimated with sonography, especially for the tumour groups IDC + DCIS, IDC and ILC. The greatest difference between sonographic sizing and actual histological tumour size was found with invasive lobular breast cancer. There was no significant difference between mammographic and histological sizing. MRI overestimated non-significantly the tumour size and is superior to the other imaging techniques in sizing of IDC + DCIS and ILC. CONCLUSIONS: The histological subtype should be included in imaging interpretation for planning surgery in order to estimate the histological tumour size as accurately as possible.

Current Status and New Developments in Breast MRI.

SUMMARY: Breast magnetic resonance imaging (MRI) is the most sensitive imaging modality for the detection of breast cancer. Its specificity is equivalent to that of mammography. Nowadays, breast MRI is an absolutely essential breast imaging method. Technical innovations allow dynamic contrast-enhanced (DCE) MRI of both breasts with high image quality. Thereby, DCE breast MRI should always be performed with regard to current standards. New quantitative techniques such as diffusion-weighted MRI are promising. However, they still have potential pitfalls, in particular with regard to the diagnosis of non-mass lesions and small breast lesions. Ongoing technical innovations can possibly help to further optimize breast MRI.

Dynamic magnetic resonance imaging for assessment of minimally invasive pelvic floor reconstruction with polypropylene implant.

INTRODUCTION: The purpose of the study was to assess the usefulness of dynamic MRI in patients with pelvic organ prolapse after pelvic floor repair with polypropylene mesh. MATERIALS AND METHODS: Fifteen consecutive patients (mean age 66.5 years) who were scheduled for either anterior (n=9) or posterior (n=6) pelvic floor repair were prospectively evaluated by clinical assessment and dynamic MRI 1 day before and 3 months after surgery. MRI diagnoses and MRI measurements of relevant anatomical points at rest and on straining were analysed before and after surgery. RESULTS: At follow-up assessment 93.3% of all patients were clinically cured. Dynamic MRI showed newly developed (n=6) or increased (n=6) pelvic organ prolapse in 80% (n=12) of all patients 3 months after pelvic floor repair. Most of them (n=11; 91.7%) affected the untreated pelvic floor compartment. On straining anatomical points of reference in the anterior pelvic floor compartment were significantly (p<0.05) elevated after anterior repair and rectal bulging was significantly (p=0.036) reduced after posterior pelvic floor repair. CONCLUSIONS: In this study dynamic MRI could verify the effective support of anterior and posterior pelvic floor structures by anterior and posterior polypropylene implant respectively. But dynamic MRI demonstrates if one compartment of the pelvic floor is repaired another compartment frequently (73.3%) develops dysfunction. These results did not correspond to clinical symptoms on short-term follow-up (3 months). Studies with long-term follow-up are necessary to prove if dynamic MRI can reliably identify clinically significant pelvic organ prolapse after pelvic floor repair before the onset of symptoms.

Multicenter, double-blind, randomized, intraindividual crossover comparison of gadobenate dimeglumine and gadopentetate dimeglumine for Breast MR imaging (DETECT Trial).

PURPOSE: To intraindividually compare 0.1 mmol/kg doses of gadobenate dimeglumine and gadopentetate dimeglumine for contrast material-enhanced breast magnetic resonance (MR) imaging by using a prospective, multicenter double-blind, randomized protocol. MATERIALS AND METHODS: Institutional review board approval and patient informed consent were obtained. One hundred sixty-two women (mean age, 52.8 years ± 12.3 [standard deviation]) enrolled at 17 sites in Europe and China between July 2007 and May 2009 underwent at least one breast MR imaging examination at 1.5 T by using three-dimensional spoiled gradient-echo sequences. Of these, 151 women received both contrast agents in randomized order in otherwise identical examinations separated by more than 2 but less than 7 days. Images, acquired at 2-minute or shorter intervals after contrast agent injection, were evaluated independently by three blinded radiologists unaffiliated with enrollment centers. Histopathologic confirmation was available for all malignant lesions (n = 144), while benign lesions were confirmed either by using histopathologic examination (n = 52) or by at least 12-month diagnostic follow-up (n = 20) with mammography and/or ultrasonography. Determinations of malignant lesion detection rates and diagnostic performance (sensitivity, specificity, accuracy, positive predictive value [PPV], and negative predictive value [NPV]) were performed and compared (McNemar and Wald tests). A full safety assessment was performed. RESULTS: Significant superiority for gadobenate dimeglumine was noted by readers 1, 2, and 3 for malignant lesion detection rate (91.7%, 93.1%, 94.4% vs 79.9%, 80.6%, 83.3%, respectively; P ≤ .0003). Readers 1, 2, and 3 reported significantly superior diagnostic performance (sensitivity, specificity, and accuracy) for breast cancer detection with gadobenate dimeglumine (91.1%, 94.5%, 95.2% vs 81.2%, 82.6%, 84.6%; 99.0%, 98.2%, 96.9% vs 97.8%, 96.9%, 93.8%; 98.2%, 97.8%, 96.7% vs 96.1%, 95.4%, 92.8%, respectively; P ≤ .0094) and significantly superior PPV (91.1%, 85.2%, 77.2% vs 80.7%, 75.5%, 60.9%, respectively; P ≤ .0002) and NPV (99.0%, 99.4%, 99.4% vs 97.8%, 98.0%, 98.1%, respectively; P ≤ .0003). No safety concerns were noted with either agent. CONCLUSION: Gadobenate dimeglumine is superior to gadopentetate dimeglumine for breast cancer diagnosis. © RSNA, 2010 Clinical trial registration no. NCT00486473 (http://www.clinicaltrials.gov/). SUPPLEMENTAL MATERIAL: http://radiology.rsna.org/lookup/suppl/doi:10.1148/radiol.10100968/-/DC1.

In vitro assessment of artifacts from commercially available markers for image-guided preoperative marking of bone and soft tissue lesions.

PURPOSE: To evaluate the magnetic resonance (MR) imaging artifacts from several commercially available MR imaging-compatible and non-MR imaging-compatible markers for image-guided marking of soft tissue lesions at different field strengths and sequences. MATERIALS AND METHODS: Ten different marking devices (anchor, coil, V, and X shapes) were injected into solid agar and imaged at two different field strengths (1.5 T, 3.0 T) and with three MR sequences (T1-weighted three-dimensional fast low-angle shot, T1-weighted two-dimensional fast low-angle shot MR fluoroscopy, and T2-weighted short inversion time inversion-recovery). Artifacts were assessed quantitatively by evaluating the areas of signal extinction and calculating equivalent diameters and qualitatively by visual grading. Paired t tests were used to assess the influence of sequence types and field strengths. RESULTS: Artifact diameters ranged from negligible to 45.8 mm. Sequence types and field strength did not have a statistically relevant influence on the artifact size. All artifacts from non-MR imaging-compatible V- and X-shaped markers were rated as "too large;" the artifacts from MR imaging-compatible V- and X-shaped markers and from all anchor-shaped devices were rated as "too small." The highest ratings were achieved by an MR imaging-compatible coil-shaped marker. CONCLUSIONS: The artifacts of the tested marking devices are mainly determined by their shapes and materials. Sequence types and field strengths have only a small influence on the artifacts. The most distinguished signal voids with an intermediate size resulted from an MR imaging-compatible coil-shaped marker.

Low-cost phantoms for training of stereotactic vacuum-assisted biopsy of the breast.

To test low-cost phantoms for training in stereotactic breast biopsy, we prepared eggplant with calcium powder; gelatin and turkey breast with coarse salt, peppercorns, and calcium powder, respectively; and short-bread pastry with salt. Three to 12 cores were harvested with an 11-gauge vacuum biopsy unit. Mammography images were taken before and after biopsy and from the biopsy cores. The pastry phantom provided the best simulation of microcalcifications for stereotactic biopsy with realistic cores, long durability, and short preparation time.

Diagnostic value of MR elastography in addition to contrast-enhanced MR imaging of the breast-initial clinical results.

OBJECTIVE: The purpose of the study was to assess the additional value of magnetic resonance (MR) elastography (MRE) to contrast-enhanced (ce) MR imaging (MRI) for breast lesion characterisation. METHODS: Fifty-seven suspected breast lesions in 57 patients (mean age 52.4 years) were examined by ce MRI and MRE. All lesions were classified into BI-RADS categories. Viscoelastic parameters, e.g. alpha0 as an indicator of tissue stiffness, were calculated. Histology of the lesions was correlated with BI-RADS and viscoelastic properties. The positive predictive value (PPV) for malignancy, and the sensitivity and specificity of ce MRI were calculated. Receiver-operating characteristics (ROC) curves were separately calculated for both ce MRI and viscoelastic properties and conjoined to analyse the accuracy of diagnostic performance. RESULTS: The lesions (mean size 27.6 mm) were malignant in 64.9% (n = 37) of cases. The PPV for malignancy was significantly (p < 0.0001) dependent on BI-RADS classification. The sensitivity of ce MRI for breast cancer detection was 97.3% (36/37), whereas specificity was 55% (11/20). If ce MRI was combined with alpha0, the diagnostic accuracy could be significantly increased (p < 0.05; AUC(ce MRI) = 0.93, AUC(combined) = 0.96). CONCLUSIONS: In this study, the combination of MRE and ce MRI could increase the diagnostic performance of breast MRI. Further investigations of larger cohorts and smaller lesions (in particular those only visible on MRI) are necessary to validate these results.

Mammotome versus ATEC: a comparison of two breast vacuum biopsy techniques under sonographic guidance.

PURPOSE: The study evaluates the differences between the Mammotome (MT) and ATEC (A) vacuum biopsy (VB) of the breast in terms of diagnostic reliability, biopsy duration and complications. METHODS: In a prospective randomized study, 62 ultrasound-guided VBs of the breast were performed. MT and A were compared using Mann-Whitney U test. RESULTS: The mean lesion size and the BI-RADS distribution were equal in both groups. Representative tissue was extracted in all 62 biopsies; thus no repeat biopsies were necessary. A sonographically guided complete excision was possible in 46 cases. More imaging-guided complete excisions were achieved with the MT than with A (87 vs. 63%). Technical complications occurred twice with A and once with MT. No medical complications occurred in either group. CONCLUSIONS: Both systems are suitable for the diagnostic clarification of unclear breast lesions as well as complete excision of benign lesions under sonographic imaging. Sonographically guided complete resection was achieved more often with the MT.

MR elastography of breast lesions: understanding the solid/liquid duality can improve the specificity of contrast-enhanced MR mammography.

The purpose of this analysis is to explore the potential diagnostic gain provided by the viscoelastic shear properties of breast lesions for the improvement of the specificity of contrast enhanced dynamic MR mammography (MRM). The assessment of viscoelastic properties is done via dynamic MR elastography (MRE) and it is demonstrated that the complex shear modulus of in vivo breast tissue follows within the frequency range of clinical MRE a power law behavior. Taking benefit of this frequency behavior, data are interpreted in the framework of the exact model for wave propagation satisfying the causality principle. This allows to obtain the exponent of the frequency power law from the complex shear modulus at one single frequency which is validated experimentally. Thereby, scan time is drastically reduced. It is observed that malignant tumors obtain larger exponents of the power law than benign tumors indicating a more liquid-like behavior. The combination of the Breast Imaging Reporting and Data System (BIRADS) categorization obtained via MRM with viscoelastic information leads to a substantial rise in specificity. Analysis of 39 malignant and 29 benign lesions shows a significant diagnostic gain with an increase of about 20% in specificity at 100% sensitivity.

Leiomyoma in the Retzius space: a rare cause for voiding difficulties.

A 54-year-old woman with voiding difficulties was referred to our department. She complained about a slow urine stream, hesitancy, straining when voiding and the feeling of incomplete emptying. The gynaecological examination revealed a 4x3 cm pelvic tumour. The tumour was well circumscribed in the retropubic space between the symphysis and the bladder neck sonographically and by magnetic resonance imaging and was closed off from neighbouring structures. After removal of the tumour, the voiding problems were reversed, and the patient has remained asymptomatic. The histological examination showed a leiomyoma with high vascularisation. This case report showed that retropubic tumours can obstruct the urethra and cause voiding dysfunctions. Consequently, this needs to be considered in the differential diagnosis.

Magnetic resonance imaging of the body trunk using a single-slab, 3-dimensional, T2-weighted turbo-spin-echo sequence with high sampling efficiency (SPACE) for high spatial resolution imaging: initial clinical experiences.

PURPOSE: The authors conducted a clinical evaluation of single-slab, 3-dimensional, T2-weighted turbo-spin-echo (TSE) with high sampling efficiency (SPACE) for high isotropic body imaging with large field-of-view (FoV). MATERIALS AND METHODS: Fifty patients were examined in clinical routine with SPACE (regions of interest: pelvis n=30, lower spine n=12, upper spine n=6, extremities n=4) at 1.5 T. For achieving a high sampling efficiency, parallel imaging, high turbofactor, and magnetization restore pulses were used. In contrast to a conventional TSE imaging technique with constant flip angle refocusing, the refocusing pulse train of the SPACE sequence consists of variable flip angle radiofrequency pulses along the echo train. RESULTS: Signal-to-noise ratio and contrast-to-noise ratio of SPACE images were of sufficient diagnostic value. The possibility of image reconstruction in multiple planes was of clinical relevance in all cases and simplified data analysis. CONCLUSION: The achievement of 3-dimensional, T2-weighted TSE magnetic resonance imaging with isotropic and high spatial resolution and interactive 3-dimensional visualization essentially improve the diagnostic potential of magnetic resonance imaging.

Magnetic resonance elastography of the breast: correlation of signal intensity data with viscoelastic properties.

OBJECTIVES: We sought to investigate the potential value of magnetic resonance (MR) elastography to improve the differentiation between benign and malignant tumors. MATERIAL AND METHODS: Measurements of 5 patients with 6 malignant lesions, 11 patients with benign lesions, and 4 patients with no lesions at all were performed at 1.5 Tesla. After breast MR imaging, MR elastography was performed as a targeted measurement. Low-frequency mechanical waves (65 Hz) were transmitted into the breast tissue using an oscillator and were displayed by means of a MR sequence within the phase of the MR image. After reconstruction, the viscoelastic information was correlated with the signal intensity and morphology data. RESULTS: All examinations were technically successful realized in approximately 25 minutes. Malignant tumors documented higher values of elasticity than benign corresponding with signal intensity and morphologic data. CONCLUSION: A good separation exists between benign and malignant lesions in elasticity, corresponding with specific signal intensity and morphologic data. Further clinical studies with a larger number of patients are needed for extended validation.

Preoperative magnetic resonance imaging-guided localization of 131 breast lesions with modified embolization coils.

OBJECTIVES: The objectives of this study were to assess practicability, outcome, and possible advantages of magnetic resonance imaging (MRI)-guided localizations with modified embolization coils for exclusively MRI-detected suspicious breast lesions. MATERIALS AND METHODS: We performed 131 MRI-guided preoperative localizations in 105 patients with exclusively MRI-detected breast lesions. Contrast-enhanced, T1-weighted, 3-dimensional gradient echo sequences were used for imaging. Breast fixation and needle guidance were achieved by a perforated plate. Lesion localization was performed with a modified embolization coil. The distance between coil and lesion was measured. Results of specimen radiography and histopathology were analyzed. RESULTS: Thirty-four of 131 lesions (26%) were malignant. Lesion localization and excision was successful in all patients. The mean distance between the coil and the lesion was 0.5 mm (+/-1.7 mm standard deviation). CONCLUSIONS: Exact MRI-guided preoperative localization of exclusively MRI-detected breast lesions by using a modified embolization coil is feasible with excellent precision. Advantages over wire localization procedures are the possibility of specimen x-ray and the independence from time and place of operation.

MR imaging-detected breast lesions: histopathologic correlation of lesion characteristics and signal intensity data.

OBJECTIVE: The aim of our study was to differentiate benign from malignant breast lesions that had been detected exclusively on MR imaging by analyzing qualitative and quantitative lesion characteristics. MATERIALS AND METHODS: We performed 51 MR imaging-guided breast interventions (41 preoperative lesion localizations and 10 large-core needle biopsies) in 45 patients with exclusively MR imaging-detected lesions. All patients had previously undergone diagnostic dynamic contrast-enhanced MR imaging of the breast with a double breast coil at 1.0 T (n = 36) or 1.5 T (n = 15). The diagnostic MR images were evaluated on a workstation. Lesion morphology (size, shape, margin type, enhancement pattern), signal intensity parameters (time to peak enhancement, maximum slope of enhancement curve, washout, relative water content), and scores analogous to the Breast Imaging Reporting and Data System (BI-RADS) categories were correlated with histology. RESULTS: Histology revealed malignancy in 37.3% (19/51) of the lesions. The positive predictive value for malignancy of exclusively MR imaging-detectable lesions increased as the analogous BI-RADS category increased. Late inhomogeneous contrast enhancement was the only morphologic criterion that was statistically significantly correlated with malignancy. Malignant and benign lesions did not differ significantly in any of the quantitatively evaluated signal intensity parameters. Carcinomas showed a tendency toward faster and stronger enhancement and stronger washout. CONCLUSION: The classification of exclusively MR imaging-detectable breast lesions according to a combination of morphologic and perfusion parameters including the late enhancement pattern helps identify the lesions for which interventional MR imaging is required. Quantitative signal intensity data alone do not suffice.

Diagnostic potential of targeted electrical impedance scanning in classifying suspicious breast lesions.

RATIONALE AND OBJECTIVE: To evaluate the potential of targeted electrical impedance scanning (EIS) for classifying suspicious breast lesions. METHODS: EIS was performed in full knowledge of mammographic findings and findings of clinical breast examination. One hundred seventeen patients with a total of 129 breast lesions were examined with EIS before breast biopsy (surgical excision or vacuum core biopsy). Diagnostic indexes of targeted EIS were calculated depending on major lesion characteristics. Capacitance and conductivity of all positive spots (S) and the surrounding normal breast tissue (NBT) were quantified using ROI measurements. The ratio S/NBT was calculated to compare true positive (n = 44) and false positive (n = 18) spots. RESULTS: With respect to histology, of the 129 lesions 71 were malignant and 58 lesions were benign. Overall sensitivity of targeted EIS was 62%, specificity 69%, PPV 71%, and NPV 60%. Sensitivity of EIS varied depending on the tumor size, which was between 48% (> 20 mm) and 71% (11-20 mm). Highest specificity (86%) was observed for large lesions (> 20 mm); however, the NPV was only 35% for lesions of that size. NPV was higher for nonpalpable lesions (74%) and clusters of microcalcifications (85.7%) compared with palpable lesions (39%) and solid lesions (44%). There was no statistical difference of S/NBT ratio neither for conductivity nor capacitance of true and false positive spots. Compared with true positive spots a trend of a higher conductivity ratio at 100 Hz and 200 Hz was seen for false positive spots. CONCLUSION: EIS showed mediocre overall diagnostic accuracy for classifying suspicious breast lesions. Quantitative analysis of positive EIS findings did not help to differentiate between false and true positive spots.