Rapid MRI of the breast in evaluating lesions discovered on screening.

BACKGROUND: In Canada, breast MRI has traditionally been reserved for evaluation of disease extent in patients with known breast malignancy. More recently, MRI has been emerging as an instrument for breast screening. However, its utilization is limited by increased relative cost and increased reader time. In this study, we evaluate a rapid MRI protocol for breast cancer screening within a breast screening population. METHODS: A series of 100 MRI studies performed in a high-risk breast cancer population were selected, ensuring a mix of malignant and benign pathology and normal cases. These were presented as full and abbreviated MRI protocols to 3 breast-trained radiologists. Each case was evaluated for Breast Imaging Reporting and Data Systems (BIRADS) category and the presence or absence of cancer. The time taken to complete and interpret each study was also recorded. RESULTS: Of the 100 cases, 17 were of histopathology-proven invasive carcinoma, 6 were ductal carcinoma in situ, 33 were benign, and 44 were normal cases. Sensitivity using the rapid protocol was 69.6% (CI: 47.1-86.8) vs 83% (CI: 61.2-95.1) using the full protocol. Specificity using the rapid protocol was 77.9% (CI: 67.0-86.6) vs 83% (CI: 61.2-95.1) using the full protocol. Intra-observer agreement of BIRADS category and cancer detection was very good (0.82-0.93 weighted Kappa and 0.81-0.9 weighted Kappa, respectively). Inter-observer variability of BIRADS category and cancer detection was moderate (0.54-0.59 and 0.53-0.58, respectively). CONCLUSION: Our study suggests that a rapid MRI protocol is comparable in performance to that of a standard MRI protocol. In addition, breast imagers are unlikely to change their BIRADS assessment of a study based on the additional sequences provided by the lengthier study. The use of a rapid MRI protocol can improve accessibility, thus making breast MRI a more utilized tool for breast cancer screening.

Deformable Registration for Longitudinal Breast MRI Screening.

MRI screening of high-risk patients for breast cancer provides very high sensitivity, but with a high recall rate and negative biopsies. Comparing the current exam to prior exams reduces the number of follow-up procedures requested by radiologists. Such comparison, however, can be challenging due to the highly deformable nature of breast tissues. Automated co-registration of multiple scans has the potential to aid diagnosis by providing 3D images for side-by-side comparison and also for use in CAD systems. Although many deformable registration techniques exist, they generally have a large number of parameters that need to be optimized and validated for each new application. Here, we propose a framework for such optimization and also identify the optimal input parameter set for registration of 3D T1-weighted MRI of breast using Elastix, a widely used and freely available registration tool. A numerical simulation study was first conducted to model the breast tissue and its deformation through finite element (FE) modeling. This model generated the ground truth for evaluating the registration accuracy by providing the deformation of each voxel in the breast volume. An exhaustive search was performed over various values of 7 registration parameters (4050 different combinations of parameters were assessed) and the optimum parameter set was determined. This study showed that there was a large variation in the registration accuracy of different parameter sets ranging from 0.29 mm to 2.50 mm in median registration error and 3.71 mm to 8.90 mm in 95 percentile of the registration error. Mean registration errors of 0.32 mm, 0.29 mm, and 0.30 mm and 95 percentile errors of 3.71 mm, 5.02 mm, and 4.70 mm were obtained by the three best parameter sets. The optimal parameter set was applied to consecutive breast MRI scans of 13 patients. A radiologist identified 113 landmark pairs (~ 11 per patient) which were used to assess registration accuracy. The results demonstrated that using the optimal registration parameter set, a registration accuracy (in mm) of 3.4 [1.8 6.8] was achieved.

Outcomes of percutaneous transluminal angioplasty for pediatric renovascular hypertension.

BACKGROUND: Up to 10% of hypertensive children will have renovascular disease. Where medical therapy fails to control the hypertension, endovascular techniques can improve renal perfusion. The purpose of this study was to assess the efficacy of angioplasty in controlling renovascular hypertension (RVH) in children. METHODS: This is a single-center, retrospective review of patients who underwent angioplasty for RVH between 1992 and 2009. All patients were selected from the Interventional Radiology database. The primary outcome measure was clinical success as reflected by a favorable, sustained response in blood pressure for at least 1year following the angioplasty. RESULTS: Two hundred sixteen patients underwent diagnostic angiography for suspected RVH, of these 28 required 42 angioplasties. Ten (36%) were cured, 9 (32%) were improved and 9 (32%) failed to respond to treatment. Major complications occurred in three patients and minor complications occurred in 18 angioplasties. Fibromuscular dysplasia (FMD) was the most common diagnosis in this series and was associated with a 79% success rate. CONCLUSION: In our exclusively pediatric population angioplasty safely improved blood pressure control in 68% of patients, more than half of which are cured. FMD appeared to have the best clinical outcomes in our series.

Fine-needle aspiration biopsy of breast adenomyoepithelioma: a potential false positive pitfall and presence of intranuclear cytoplasmic inclusions.

Cytologic diagnosis of adenomyoepithelioma can be very challenging. We report fine needle aspiration cytology (FNAC) findings of a benign adenomyoepithelioma. The cytologic features are characterized by hypercellularity and the presence of numerous atypical dispersed cells with epithelioid morphology and intact cytoplasm. The nuclei showed stippled chromatin, irregular nuclear membrane, and prominent eosinophilic nucleoli. No necrosis or mitoses were seen. The presence of naked nuclei, and extensive intranuclear cytoplasmic inclusions were identified and raised the possibility of adenomyoepithelioma. Immunohistochemically, the atypical cells showed strong positivity for myosin heavy chain, p63, and CK5/6, while the epithelial cells reacted with estrogen receptors. This immunophenotypic pattern supports the myoepithelial origin of the atypical cell proliferation and favors the diagnosis of benign adenomyoepithelioma. However, biopsy was recommended to exclude malignancy. Histologically, the tumor showed prominent myoepithelial cells with significant atypia, intranuclear cytoplasmic inclusions, and dense cytoplasm. No evidence of malignancy was identified. In conclusion, we report a case of adenomyoepithelioma with a significant cytological atypia that may result in confusion with malignant breast tumors. The presence of intranuclear cytoplasmic inclusions, naked nuclei, and expression of myoepithelial markers should provide clues to the right diagnosis and benign nature of this lesion. Cytopathologists should be familiarized with this entity to avoid a misdiagnosis of carcinoma.

Skin breakdown over cochlear implants: prevention of a magnet site complication.

OBJECTIVE: To determine the prevalence of inflammation of the skin around the magnet of cochlear implants. METHOD: A postal survey of 232 children implanted at The Hospital for Sick Children, Toronto, detailing the timing and severity of skin inflammation near the magnet. RESULTS: Sixty-three children (27%) had at least one episode of skin erythema at the magnet site. In most cases, this resolved after reducing magnet field strength. Nine children stopped wearing the device briefly, and five were treated with antibiotics. Skin ulceration occurred in two cases. No surgical treatment was required. Reactions tended to occur in younger children (2.8 vs 4.3 years; p = .002, Mann-Whitney rank sum test). CONCLUSIONS: Skin inflammation commonly occurs in children between magnets of the transmitter and receiver coils of a cochlear implant. If inflammation fails to resolve after loosening the magnet, use of the implant should be discontinued temporarily. Antibiotics should be prescribed for cellulitis to prevent an implant-threatening infection.