MRI Roles in the Differentiation Between Benign and Malignant Breast Lesions in Baghdad City View PDF

BC is the first most common cancer in women. According to the NCCN project report about 2 million women develop BC in world per year. It is a significant cause of worldwide morbidity and mortality. MR techniques have shown strong potential to improve the sensitivity and specificity in the diagnosis of BC [1]. MRI is recommended by the ACS as an adjunct to mammography for screening females who are at high risk of developing BC [2]. It seems to be ideally useful for breast imaging due to its ability to depict excellent soft tissue contrast. Contrast enhanced MRI and dynamic MRI have been found to be more accurate in the detection of malignant lesions and differentiation of malignancy vs. scarring. In addition, MRI can also be used to assess ALN metastasis. DCE-MRI of breast is a very sensitive method for detecting small lesions which are not visualized by conventional MR. BC have variable vascularization DCE-MRI patterns, which are divided due to the internal enhancement pattern, enhancement distribution, and kinetic studies on DCE-MRI. According to BIRADS lexicon, kinetic curves are classified as ‘‘washout,’ ‘‘plateau,’’ or ‘‘persistent’’ shape [3]. DWI has shown promise for the detection and characterization of BC. Apparent diffusion coefficient (ADC) values allow quantification of diffusion signal and can facilitate in differentiating benign and malignant breast lesions as well as identifying early responses preoperative treatment [4]. It is performed using at least two b values. Theoretically, the error in ADC calculation can be reduced by using La Prensa Medica Argentina MRI Roles in the Differentiation Between Benign and Malignant Breast Lesions in Baghdad City Lubna Ali Hussien1* and Ruaa Mohammed Hasan Waheed2 1 Department of Radiology, Kamal Al-Samarai Hospital for Fertility and Infertility, Ministry of Health, Baghdad, Iraq 2 Gastroenterology and Hepatology Teaching Hospital, Baghdad Medical City, Ministry of Health, Baghdad, Iraq Research Article DOI: https://doi.org/10.47275/0032-745X-413 Volume 110 Issue 3 more b values. However, the more b values used, the longer the DWI sequence will be [5, 6]. The aim was to estimate the roles of DWI-MRI and DCE-MRI in distinguishing benign from malignant breast lesions.

Design and setting

A descriptive radiological study was conducted in the department of radiology between June 2023 and December 2023 at Medical City. A total of 50 cases with palpable breast lump referred from various hospitals were included in the study.

Inclusion criteria

Cases with palpable breast lump with either positive findings on mammography or US.

Exclusion criteria

• Cases who had received chemotherapy, radiotherapy and surgery.
• Impaired renal function.
• Allergy to contrast medium.
• Pacemaker and shells.

Complete history and clinical examination were done. Relevant laboratory investigations were noted.

Equipment and protocols

MRI examination was performed utilizing the 1.5 Tesla Siemens system (Magnetom Aera; Siemens Healthineers, Erlangen, Germany). The protocol applied included: T1(t1-fl2d) axial, T2 (t2-tse) axial, T2 fat suppression (t2-haste-fs) axial, T2 (t2-tse) coronal/or sagittal and T1 fat suppression (t1-tse-fs) axial and coronal /or sagittal before and after injection of IV contrast (gadolinium ) at a dose of 0.1 mmol/kg.

The post contrast images were taken in the early phase (45-60 sec post injection) for all the cases, and additional post contrast images were taken in the delayed phase (5 minutes post injection ) in cases that showed masses with very hyperintense signal in T2WI.

Diffusion weighted images (DWI) and Apparent diffusion coefficient (ADC) values

DWI were performed for all the included cases before giving IV contrast using single shot echo planer imaging sequence EPI in axial plane. The parameters were: TR = 5580 ms, TE = 75 ms, slice thickness = 4 mm, b values (50, 400, and 800 mm/sec2 ). All diffusion images and conventional images were obtained at the same slice locations. The ADC value was measured by applying region of interest (ROI) on the solid part of the tumor avoiding any area of necrotic, cystic or hemorrhagic changes and encircling in the most prominent restrictive diffusion. Three ROIs were applied for each tumor and the mean of the ADC values was calculated.

Statistical analysis

All statistical calculations were done using (Statistical Package for the Social Science) SPSS 24 version (SPSS Inc., Chicago, IL, USA) statistical program for Microsoft Windows. Data was described in terms of range; mean ± SD, frequencies (number of cases) and relative frequencies (percentages) as appropriate. Comparison of quantitative variables between the study groups was done using Student t-test. Sensitivity, specificity, accuracy, positive predictive value and negative predictive value were also calculated. A probability value (P- value) less than 0.05 was considered statistically significant.

Out of the total 50 breast lesions, FNAC or biopsy analysis revealed 20 benign lesions (40%) and 30 malignant lesions (60%). Among the benign lesions, fibroadenoma was the most common pathology seen in 8/20 cases, while IDC accounted for most of the malignant lesions seen in 30/30 cases. The youngest case being 18 years old and oldest being 65 years old (Table 1)

Diffusion and ADC values of benign and malignant lesions

Out of 20 benign breast lesions 16 lesions did not show diffusion restriction on DWI. 2 cases of granulomatous mastitis showed diffusion restriction. The minimum ADC value was 0.96 x 10-3 mm2 /s seen in granulomatous mastitis while maximum ADC value was 2.2 x 10-3 mm2 / s/s seen in case of fibroadenoma. The mean ADC value for benign breast lesion was 1.58 x 10-3 mm2 /s.

All the malignant breast lesions show diffusion restriction on DWI. 15 out of 30 malignant lesions had ADC values >1 x 10-3 mm2 /s. The least ADC value was 0.7 x 10-3 mm2 /s seen in IDC. While the maximum ADC value was 1.22 x 10-3 mm2 /s seen in IDC. The mean ADC value was calculated as 0.89 x 10-3 mm2 /s. 16 out of 20 benign lesions did not show restricted diffusion on DWI while 2 cases of granulomatous mastitis showing restricted diffusion on DWI. The mean ADC value calculated in benign lesion was 1.58. All the malignant lesions show restricted diffusion on DWI with mean ADC value calculated as 0.89 (Figure 1).

Accuracy values

In this study the sensitivity and specificity of MRI with contrast was calculated as 96% and 71% respectively. In our study 16/20 benign lesions did not show restricted diffusion on DWI. All the malignant breast lesions showed restricted diffusion on DWI. In our study the sensitivity and specificity of DWI to differentiate between benign and malignant lesions were 96% and 92% respectively. In our study the cutoff value of ADC to differentiate between benign and malignant lesions was calculated to be 1.20 x 10-3 mm2 /s. This yielded a sensitivity of 90% and specificity of 95%. The accuracy for MRI with contrast was 86% whereas for DWI was 94% (Table 2).

12 out of 20 benign lesions were either round or oval. 10 out of 20 benign lesions were well circumscribed margins. Our data are in concordance with Qu et al. [7] who observed that 19 out of 23 fibroadenomas were lobular, oval or round.

In this study 10/20 benign lesions showed hypointense signal on T1WI, while 12/20 lesions showed hyperintense signal on T2WI. These are in concordance with Westra et al. [8] who reported that most masses with high signal intensity at T2WI were benign.

In our study 27 out of 30 malignant lesions had irregular shape and 23/30 malignant lesions showed spiculated margins. Our data are like those reported by Zhang et al. [9] who found that larger mass size, irregular shape and irregular or spiculated margins were associated with higher odds of malignancy than smaller, smooth marginated masses.

In our study 28 out of 30 malignant lesions showed hypointense signal on T1WI while 26 out of 30 malignant lesions showed hypointense signal on T2WI. These are in concordance with a study by Westra et al. [8] who reported that most malignant lesions do not show high signal intensity on T2WI because of their high cellularity and low water content.

All the benign lesions showed enhancement on post contrast scans. The most common enhancing pattern was homogenous enhancement which was seen in 12 out of 20 benign breast lesions (60%). Zhang et al. [9] also pointed out that lesion measuring more than 1 cm in size and showing homogenous enhancement was more likely to be benign.