Breast magnetic resonance imaging: current clinical indications

A rapid landscape review of postpartum anaemia measurement: challenges and opportunities

BACKGROUND

Anaemia is a reduction in haemoglobin concentration below a threshold, resulting from various factors including severe blood loss during and after childbirth. Symptoms of anaemia include fatigue and weakness, among others, affecting health and quality of life. Anaemic pregnant women have an increased risk of premature delivery, a low-birthweight infant, and postpartum depression. They are also more likely to have anaemia in the postpartum period which can lead to an ongoing condition and affect subsequent pregnancies. In 2019 nearly 37% of pregnant women globally had anaemia, and estimates suggest that 50-80% of postpartum women in low- and middle-income countries have anaemia, but currently there is no standard measurement or classification for postpartum anaemia.

METHODS

A rapid landscape review was conducted to identify and characterize postpartum anaemia measurement searching references within three published systematic reviews of anaemia, including studies published between 2012 and 2021. We then conducted a new search for relevant literature from February 2021 to April 2022 in EMBASE and MEDLINE using a similar search strategy as used in the published reviews.

RESULTS

In total, we identified 53 relevant studies. The timing of haemoglobin measurement ranged from within the immediate postpartum period to over 6 weeks. The thresholds used to diagnose anaemia in postpartum women varied considerably, with < 120, < 110, < 100 and < 80 g/L the most frequently reported. Other laboratory results frequently reported included ferritin and transferrin receptor. Clinical outcomes reported in 32 out of 53 studies included postpartum depression, quality of life, and fatigue. Haemoglobin measurements were performed in a laboratory, although it is unclear from the studies if venous samples and automatic analysers were used in all cases.

CONCLUSIONS

This review demonstrates the need for improving postpartum anaemia measurement given the variability observed in published measures. With the high prevalence of anaemia, the relatively simple treatment for non-severe cases of iron deficiency anaemia, and its importance to public health with multi-generational effects, it is crucial to develop common measures for women in the postpartum period and promote rapid uptake and reporting.

3D DCE-MRI Radiomic Analysis for Malignant Lesion Prediction in Breast Cancer Patients

RATIONALE AND OBJECTIVES

To develop and validate a radiomic model, with radiomic features extracted from breast Dynamic Contrast-Enhanced Magnetic Resonance Imaging (DCE-MRI) from a 1.5T scanner, for predicting the malignancy of masses with enhancement. Images were acquired using an 8-channel breast coil in the axial plane. The rationale behind this study is to show the feasibility of a radiomics-powered model that could be integrated into the clinical practice by exploiting only standard-of-care DCE-MRI with the goal of reducing the required image pre-processing (ie, normalization and quantitative imaging map generation).

MATERIALS AND METHODS

107 radiomic features were extracted from a manually annotated dataset of 111 patients, which was split into discovery and test sets. A feature calibration and pre-processing step was performed to find only robust non-redundant features. An in-depth discovery analysis was performed to define a predictive model: for this purpose, a Support Vector Machine (SVM) was trained in a nested 5-fold cross-validation scheme, by exploiting several unsupervised feature selection methods. The predictive model performance was evaluated in terms of Area Under the Receiver Operating Characteristic (AUROC), specificity, sensitivity, PPV and NPV. The test was performed on unseen held-out data.

RESULTS

The model combining Unsupervised Discriminative Feature Selection (UDFS) and SVMs on average achieved the best performance on the blinded test set: AUROC = 0.725±0.091, sensitivity = 0.709±0.176, specificity = 0.741±0.114, PPV = 0.72±0.093, and NPV = 0.75±0.114.

CONCLUSION

In this study, we built a radiomic predictive model based on breast DCE-MRI, using only the strongest enhancement phase, with promising results in terms of accuracy and specificity in the differentiation of malignant from benign breast lesions.

MRI-guided breast needle core biopsies: pathologic features of newly diagnosed malignancies

Magnetic resonance imaging (MRI) of the breast is used for select groups of patients. MRI-guided breast core needle biopsies performed over a 3-year period were retrospectively reviewed to determine the incidence and types of cancers found and to correlate the cancers with the MRI findings and the indication for the study. Patients were stratified based on indication for MRI examination including, evaluation of disease extent in patients with current ipsilateral carcinoma, surveillance for recurrence of prior ipsilateral carcinoma, as a problem-solving method and for screening high-risk patients. The high-risk screening group included those with family history (with or without germline mutations), prior chest wall radiation, and contralateral breast carcinoma (current or prior). Four-hundred and forty-five biopsies were performed on 386 patients. The majority of biopsies (79%) were benign. Biopsies demonstrating ductal carcinoma in situ (DCIS) and invasive carcinoma were more likely to present as nonmass-like and mass-forming enhancements respectively, but with only 52% specificity. The highest rate of malignancy (44%) was seen in the least frequently biopsied patient group (n = 25), those with prior ipsilateral carcinoma. Conversely, the most frequently biopsied group (n = 283), the high-risk screening group, demonstrated the lowest malignancy rate (16%). Within this group, most malignant cases were invasive carcinomas (n = 27), 67% of which were small (≤1 cm), well or moderately differentiated with a good prognostic receptor profile (estrogen receptor positive, human epidermal growth factor receptor 2 negative), and lacked nodal macrometastases. The remaining malignant cases in the high-risk screening group were DCIS with or without microinvasion (n = 18), 78% of which demonstrated high nuclear grade. Overall, enhancement pattern did not correlate with the likelihood of or type of malignancy. The most common types of carcinomas identified by screening were small estrogen receptor positive invasive tumors and high grade DCIS.

Dynamic contrast-enhanced and ultra-high-resolution breast MRI at 7.0 Tesla

OBJECTIVE

To assess the feasibility of 7-T contrast-enhanced breast MRI in patients with suspicious masses.

METHODS

Twenty patients with 23 suspicious breast masses on conventional imaging (mean size 13 mm, range 5-27 mm) were examined at 7 T. The MRI protocol included a dynamic series with injection of 0.1 mmol/kg gadobutrol (seven consecutive 3D T1-weighted gradient echo sequences, resolution 1 × 1 × 2 mm(3), temporal resolution 63 s) and ultra-high-resolution imaging (T1-weighted 3D gradient echo sequence, resolution 0.45 × 0.57 × 0.45 mm(3)). Two observers (R1 and R2) independently judged the examinations on image quality and classified lesions according to BI-RADS. The added value of ultra-high-resolution imaging was assessed.

RESULTS

The image quality was deemed excellent in 1 and 0, good in 10 and 12, sufficient in 8 and 8, and insufficient in 1 and 0 for R1 and R2 respectively. Twenty of the 23 lesions were identified at 7-T MRI by both observers. All histopathologically proven malignant lesions (n = 19) were identified and classified as BI-RADS-MRI 4 or 5. Ultra-high-resolution imaging increased reader confidence in 88 % (R1) and 59 % (R2) of acquisitions.

CONCLUSION

The study shows the feasibility of dynamic contrast-enhanced 7-T breast MRI, where all malignant mass lesions were identified by two observers.

KEY POINTS

• Magnetic resonance imaging is important in the evaluation of breast cancer. • Recently, 7-T MRI has become available. • The 7-T dynamic contrast-enhanced breast MRI is feasible in patients. • The 7-T breast examinations are amenable to evaluation according to BI-RADS.

Novos métodos funcionais na avaliação de lesões mamárias

O câncer de mama é um dos mais prevalentes nas mulheres. A mamografia é um excelente método com impacto comprovado na redução da mortalidade pelo câncer de mama. Porém, não é um método perfeito, apresentando alguns pontos fracos, principalmente no rastreamento de mulheres com mamas densas, estadiamento e avaliação de tratamento. A ressonância magnética mamária mostrou a necessidade e importância da avaliação funcional mamária. Descrevemos dois métodos de avaliação funcional mamária e demonstramos nossa experiência com a mamografia digital com contraste e com a imagem molecular mamária realizada em gama-câmara específica. Estes dois métodos já estão disponíveis em nosso meio e apresentam resultados promissores na detecção de lesões mamográficas ocultas, confirmação de lesões suspeitas e redução de biópsias desnecessárias, podendo assim melhorar o estudo mamário, principalmente nos pontos falhos da mamografia.