Breast MRI artefacts: evaluation and solutions in 630 consecutive patients.

AIM: To evaluate the problems that may arise in breast magnetic resonance imaging (MRI) related to the presence of artefacts and pitfalls, in order to improve its accuracy, sensitivity, and specificity. MATERIALS AND METHODS: Six hundred and thirty breast MRI examinations performed using a 1.5 T magnet were analysed retrospectively. Each type of artefact that may have affected the correct interpretation of the acquired images was considered and analysed. In particular, the presence of technical artefacts, which are related to patient-dependent factors or to the examination itself, and non-technical artefacts, which are the result of inadequate and incorrect image interpretation occurring in absence of technical issues, were examined. In every case of suspicious findings, doubtful lesions were subjected to histological characterization for appropriate therapeutic planning. In the remainder of cases, patients underwent follow-up for at least 18 months. RESULTS: Artefacts were found in 33% of all examinations, among those 48.6% were caused by movement, 33.6% were due to non-homogeneous or failed fat saturation, 8.7% to incorrect positioning of the patient, 7.2% to metallic artefacts, 1.4% to aliasing, and 0.5% were "zebra artefacts". When the artefact was identified in a sequence, the sequence was performed a second time after corrective measures. No artefacts affected diagnostic interpretation of the obtained images. CONCLUSION: The present study provides a specific and precise review of the most frequent artefacts with a discussion of possible and practical solutions. A highly qualified team is required to perform accurate diagnostic tests and to limit or remove the possibility of misinterpretation.

An unusual case of bilateral granulomatous mastitis.

Idiopathic granulomatous mastitis (IGM) is an uncommon benign disorder of the breast. At clinical examination, IGM is characterized by an inflammatory process of the breast, usually unilateral. Possible clinical findings are palpable mass with erythematous skin, pain, sterile abscesses, fistula and nipple retraction. Mammography and ultrasound findings are not specific for IGM. Magnetic resonance imaging (MRI) is a useful tool for the differential diagnosis; it is also necessary to delineate the exact extension of the disease and to plan the correct treatment. Final diagnosis is histological. We described an unusual case of IGM with bilateral involvement in a patient with history of pacemaker implantation and IGM typical clinical symptoms. Mammography, ultrasound, and MRI examinations were performed to identify the inflammatory disorder and to plan the correct therapy. Imaging features were correlated with final histological diagnosis of IGM.

The role of second-look ultrasound of BIRADS-3 mammary lesions detected by breast MR imaging.

OBJECTIVE: To asses the value of second-look ultrasound (US) for identifying BIRADS 3 (Breast Imaging Reporting Data System) mammary lesions detected by breast Magnetic Resonance imaging (MRI). MATERIALS AND METHODS: From April 2008 to May 2009 330 breast MRI were performed of which 60 patients are classified as BIRADS 3. 84 lesions underwent second-look US and percutaneous vacuum biopsy Vacora system US-guided. STATISTICAL ANALYSIS: lesions were stratified into two groups: visible on US (Group 1) and not visible on US (Group 2). The clinical impact of second-look US was studied in terms of negative predictive value (NPV). RESULTS: The positive predictive value (PPV) of category 3 BIRADS MRI was found to be 89%. Second look-US results detected lesions in 51% of the MRI enhancing lesions. The second look-US showed a NPV of 97%. The NPV of second look-US was significantly greater than the NPV of MRI BIRADS 3 (97% vs 89%, p<0.05). The logistic regression analysis showed a higher number of malignant lesions in group 1 than in group 2 (7vs 2, OR 3.7, p<0.05). CONCLUSIONS: The second-look US permitted the correct management of subcentimetric MRI BIRADS 3 lesions not visible with conventional imaging tecniques.

Cost-effectiveness of two breast biopsy procedures: surgical biopsy versus vacuum-assisted biopsy.

PURPOSE: The aim of this study was to compare the cost-effectiveness of two breast biopsy procedures: surgical biopsy and vacuum-assisted biopsy (VAB). MATERIALS AND METHODS: Between November 2008 and September 2009, 200 patients with suspicious breast lesions underwent biopsy procedures at our radiology department: 100 underwent VAB and 100 underwent surgical biopsy. 66 lesions were sampled under sonographic guidance, 109 under mammographic guidance and 25 under magnetic resonance guidance. RESULTS: All procedures were successfully completed. No significant differences in diagnostic efficacy were found between the biopsy procedures. Surgical biopsy has a higher unit cost compared with VAB. CONCLUSIONS: Our analysis emphasises the benefits of VAB compared with surgical biopsy in terms of both cost-effectiveness, and less invasiveness from a psychological and aesthetic point of view.

Value of the correct diagnostic pathway through conventional imaging (mammography and ultrasound) in evaluating breast disease.

PURPOSE: This study evaluated the role of the correct diagnostic pathway through conventional imaging in evaluating breast disease. MATERIALS AND METHODS: Six hundred patients aged between 35 and 75 years were enrolled in the study. All patients underwent detailed history and clinical examination, ultrasound (US) and mammography. US scans were repeated after mammography. All suspicious lesions were studied by cytological and histological characterisation and magnetic resonance (MR) imaging. RESULTS: The first US scan showed 147 solid lesions, 67 lesions characterised by posterior acoustic shadowing and 193 areas of heterogeneous echostructure. The second US scan, performed after mammography, confirmed 123/147 solid nodular lesions, 53/67 lesions characterised by posterior acoustic shadowing and 183/193 areas of heterogeneous echostructure; it also showed 13 nodular lesions not seen on the first scan and two cases of nodular lesions with irregular calcifications. CONCLUSIONS: Our experience suggests that US not performed in conjunction with mammography gives rise to incorrect diagnostic interpretations (either false positive or false negative results). The detection rate of the US scan performed after mammography increases from 4.16% to 5.5%.

Cost-effectiveness analysis of two vacuum-assisted breast biopsy systems: Mammotome and Vacora.

PURPOSE: This study was undertaken to compare the cost effectiveness of two vacuum-assisted breast biopsy devices, the Mammotome and Vacora systems. MATERIALS AND METHODS: Between January and June 2006, 238 vacuum-assisted breast biopsies were performed at our radiology department. Five out of 238 lesions were excluded because of inadequate sampling. The Mammotome system was used in 108/233 lesions and the Vacora system in 125/233. Fifty-eight lesions underwent ultrasound-guided breast biopsy, and 50 lesions underwent mammography-guided biopsy with both Mammotome and Vacora devices. Magnetic-resonance-guided biopsy was possible with the Vacora system only (17/125 lesions). RESULTS: All procedures were successfully completed. No significant differences were found between the results of the Mammotome and Vacora biopsies in terms of effectiveness: sensitivity was 84.4% and 86.2%, respectively, and specificity 100%. In terms of cost, the Mammotome system has higher costs per procedure compared with the Vacora. CONCLUSIONS: Our clinical results confirm the diagnostic accuracy of both the Mammotome and Vacora systems, whereas our cost analysis shows that there is a considerable difference, mostly related to the initial investment.

MR imaging-guided 10-gauge vacuum-assisted breast biopsy: histological characterisation.

PURPOSE: The aim of this study was to evaluate a handheld vacuum-assisted device for magnetic resonance imaging (MRI)-guided breast biopsy. MATERIALS AND METHODS: In 47 patients, a total of 47 suspicious breast lesions (mean maximum diameter 9 mm) seen with MRI (no suspicious changes on breast ultrasound or mammography) were sampled using a 10-gauge vacuum-assisted breast biopsy (VAB) device under MRI guidance. Histology of biopsy specimens was compared with final histology after surgery or with follow-up in benign lesions. RESULTS: Technical success was achieved in all biopsies. Histological results from VAB revealed malignancy in 15 lesions (32%), atypical ductal hyperplasia in four lesions (8%) and benign findings in 28 lesions (60%). One of four lesions with atypical ductal hyperplasia was upgraded to ductal carcinoma in situ after surgery. One of seven lesions showing ductal carcinoma was upgraded to invasive carcinoma after surgery. Two lesions diagnosed as infiltrating carcinoma by VAB were not validated at excisional biopsy due to complete removal of the lesion during the procedure. During the follow-up (mean 18 months) of histologically benign lesions, we observed no cases of breast cancer development. Because of morphological changes on follow-up MRI scans, two lesions underwent surgical excision, which confirmed their benign nature. Besides minor complications (massive bleeding, n = 1) requiring no further therapeutic intervention, no complications occurred. CONCLUSIONS: MRI-guided biopsy of breast lesions using a handheld vacuum-assisted device is a safe and effective method for the workup of suspicious lesions seen on breast MRI alone.

FEM analysis of RF breast ablation: multiprobe versus cool-tip electrode.

BACKGROUND: Radio-frequency ablation (RFA) has recently received much attention as an effective minimally invasive strategy for the local treatment of tumors. The purpose of this study was to evaluate the efficacy of single-needle cool-tip RF breast ablation in terms of temperature distribution and duration of the procedure as compared to multiprobe RF breast ablation. MATERIALS AND METHODS: Two different commercially available radiofrequency ablation needle electrodes were compared. Finite-element method (FEM) models were developed to simulate the thermoablation procedures. A series of ex vivo radiofrequency thermal lesions were induced to check the response of the FEM calculations. RESULTS: Data obtained from FEM models and from ex vivo procedures showed that cool-tip RF breast ablation assures better performances than multiprobe RF breast ablation in terms of temperature distribution and duration of the procedure. Histopathological analysis of the cool-tip RF thermoablated specimens showed successful induction of coagulation necrosis in the thermoablated specimens. CONCLUSION: Data obtained from FEM models and from ex vivo procedures suggest that the proposed cool-tip RF breast ablation may kill more tumor cells in vivo with a single application than the multiprobe RF breast ablation.