Real-time MRI navigated US: Role in diagnosis and guided biopsy of incidental breast lesions and axillary lymph nodes detected on breast MRI but not on second look US

Prospective Evaluation of Ultrasound in a Novel Position with MRI Virtual Navigation for MRI-Detected Only Breast Lesions: A Pilot Study of a More Efficient and Economical Method

The aim of this study was to evaluate the clinical utility of ultrasound (US) with magnetic resonance imaging (MRI) virtual navigation in a novel prone position for MRI-detected incidental breast lesions. Between June 2016 and June 2020, 30 consecutive patients with 33 additional Breast Imaging Reporting and Data System (BI-RADS) category 4 or 5 lesions that were detected on MRI but occult on second-look US were enrolled in the study. All suspicious lesions were located in real-time US using MRI virtual navigation in the prone position and then followed by US-guided biopsy or surgical excision. Pathological results were taken as the standard of reference. The detection rate of US with MRI virtual navigation was calculated. The MRI features and pathological types of these lesions were analyzed. A total of 31 lesions were successfully located with real-time US with MRI virtual navigation and then US-guided biopsy or localization, and the detection rate was 93.9% (31/33). Twenty-seven (87.1%, 27/31) proved to be benign lesions and four (12.9%, 4/31) were malignant lesions at pathology. Of the 33 MRI-detected lesions, 31 (93.9%, 31/33) were non-mass enhancements and two (6.1%, 2/33) were masses. This study showed that real-time US with prone MRI virtual navigation is a novel efficient and economical method to improve the detection and US-guided biopsy rate of breast lesions that are detected solely on MRI.

A Brief Review on Breast Carcinoma and Deliberation on Current Non Invasive Imaging Techniques for Detection

BACKGROUND

Breast carcinoma is a life threatening disease that accounts for 25.1% of all carcinoma among women worldwide. Early detection of the disease enhances the chance for survival.

DISCUSSION

This paper presents comprehensive report on breast carcinoma disease and its modalities available for detection and diagnosis, as it delves into the screening and detection modalities with special focus placed on the non-invasive techniques and its recent advancement work done, as well as a proposal on a novel method for the application of early breast carcinoma detection.

CONCLUSION

This paper aims to serve as a foundation guidance for the reader to attain bird's eye understanding on breast carcinoma disease and its current non-invasive modalities.

Feasibility, Image Quality and Clinical Evaluation of Contrast-Enhanced Breast MRI Performed in a Supine Position Compared to the Standard Prone Position

Background: To assess the feasibility, image quality and diagnostic value of contrast-enhanced breast magnetic resonance imaging (MRI) performed in a supine compared to a prone position. Methods: One hundred and fifty-one patients who had undergone a breast MRI in both the standard prone and supine position were evaluated retrospectively. Two 1.5 T MR scanners were used with the same image resolution, sequences and contrast medium in all examinations. The image quality and the number and dimensions of lesions were assessed by two expert radiologists in an independent and randomized fashion. Two different classification systems were used. Histopathology was the standard of reference. Results: Two hundred and forty MRIs from 120 patients were compared. The analysis revealed 134 MRIs with monofocal (U), 68 with multifocal (M) and 38 with multicentric (C) lesions. There was no difference between the image quality and number of lesions in the prone and supine examinations. A significant difference in the lesion extension was observed between the prone and supine position. No significant differences emerged in the classification of the lesions detected in the prone compared to the supine position. Conclusions: It is possible to perform breast MRI in a supine position with the same image quality, resolution and diagnostic value as in a prone position. In the prone position, the lesion dimensions are overestimated with a higher wash-in peak than in the supine position.

Feasibility of supine MRI (Magnetic Resonance Imaging)-navigated ultrasound in breast cancer patients

OBJECTIVE

The purpose of this study was to evaluate the feasibility of image fusion between US and supine MRI in breast cancer patients, and to evaluate differences in tumor location between prone and supine positions.

METHODS

This prospective study included 88 patients who underwent an additional supine MRI (MRsup) sequence following routine prone MRI (MRpro) for breast cancer between May 2016 and December 2017. The location of the tumor and discrepancies in the distances from nipple to lesion (NLD), skin to lesion (SLD), and chest wall to lesion (CLD) were evaluated between MRpro and MRsup (MRpro-sup), MRpro and MRsup-navigated US (MRpro-USnav), and MRsup and USnav (MRsup-USnav). Associations between breast thickness and measurement discrepancies were analyzed.

RESULTS

Total 91 index lesions were evaluated. The intraclass correlation coefficients (ICCs) for the location of MRpro and MRsup compared with USnav were 0.994 (range: 0.990-0.996) and 0.998 (range: 0.996-0.999), respectively. The mean MRpro-sup and MRpro-USnav measurement discrepancies were greater than those of MRsup-USnav, significantly. Most outer locations showed greater mean measurement discrepancies than inner locations, and each NLD, SLD, and CLD mean measurement discrepancy showed different tendencies according to location (upper or lower) and lesion depth (superficial, middle, or deep). High breast thickness showed significantly greater mean measurement discrepancies than low breast thickness.

CONCLUSION

Image fusion between US and supine MRI is feasible in breast cancer patients, although there is a considerable difference in tumor location measurements between prone and supine positions, especially with thicker breasts.

MRI-detected breast lesions: clinical implications and evaluation based on MRI/ultrasonography fusion technology

Magnetic resonance imaging (MRI) is a highly sensitive imaging modality that frequently reveals additional breast lesions that are occult on mammography and ultrasonography (US) and are thus difficult to diagnose. It is important to investigate these MRI-detected suspicious lesions, which are associated with a fairly high rate of malignancy. In this review, we have discussed MRI/US fusion technology, a magnetic position tracking system that synchronizes real-time US and MRI to improve lesion detection and enables comparisons of MRI and US findings of the detected lesions. This combination increases the precision of second-look US. We hope that our review underscores the importance of understanding the US findings and histopathology of MRI-detected breast lesions, as this will enable radiologists to perform appropriate assessments.

Supplementary abbreviated supine breast MRI following a standard prone breast MRI with single contrast administration: is it effective in detecting the initial contrast-enhancing lesions?

PURPOSE

We aimed to evaluate the detectability of contrast enhancing lesions, initially demonstrated in standard prone dynamic contrast-enhanced MRI (DCE-MRI), in a supplementary supine breast MRI examination performed following the standard prone DCE-MRI examination and to show the correlation of spatial displacement of the lesions with breast size and density.

METHODS

Forty-two patients with 45 lesions were prospectively evaluated. Supine breast MRI was acquired with a 6-channel body coil following a standard DCE-MRI in prone position after repositioning the patient. No additional contrast media was administered. Images were evaluated by two radiologists in consensus for the visibility of the lesions. Lesion localization relative to the sternal midline, chest wall and nipple was measured in both prone and supine positions. Correlations between lesion displacement and breast size or breast density were analyzed.

RESULTS

Of 45 lesions, 23 (52.3%) were masses, 22 (47.7%) were nonmass enhancements (NME). Forty-four lesions (97.8%) could be detected on supine images. One linear NME of 33 mm in length could not be seen on supine images. Twenty (46.5%) of the detected lesions in supine position were equal to or smaller than 10 mm (11 NME [55%] and 9 masses [45%]). Lesion displacement relative to the chest wall increased with increasing breast size (P < 0.001).

CONCLUSION

An abbreviated supine sequence following a standard prone DCE-MRI with single contrast media administration is an effective method for defining the lesion location in supine position.

Breast sentinel lymph node biopsy with imaging towards minimally invasive surgery

Breast sentinel lymph nodes are still commonly assessed through complete lymph node dissections, which is a time-consuming and radical approach because the nodes are difficult to identify. To prevent false diagnosis and achieve accurate results, minimally invasive, image-guided procedures are applied and constantly improved. The purpose of this paper is to present the currently used imaging modalities ultrasound, fluorescence, single-photon emission computed tomography (SPECT), magnetic resonance imaging (MRI) and hybrid imaging methods and comparing their effectiveness for breast sentinel lymph node biopsy. A definition for an ideal imaging system combining efficient minimally invasive techniques with workflow considerations is also discussed. As a conclusion, upcoming imaging methods and their future outlook with areas of advancement are presented.

Efficacy of Second-Look Ultrasound with MR Coregistration for Evaluating Additional Enhancing Lesions of the Breast: Review of the Literature

Contrast enhanced magnetic resonance imaging (CE-MRI) has acquired a central role in the field of diagnosis and evaluation of breast cancer due to its high sensitivity; on the other hand, MRI has shown a variable specificity because of the wide overlap between the imaging features of benign and malignant lesions. Therefore, when an additional breast lesion is identified at CE-MRI, a second look with targeted US is generally performed because it provides additional information to further characterise the target lesion and makes it possible to perform US-guided biopsies which are costless and more comfortable for patients compared with MRI-guided ones. Nevertheless, there is not always a correspondence between CE-MR findings and targeted US due to several factors including different operator's experience and position of patients. A new technique has recently been developed in order to overcome these limitations: US with MR coregistration, which can synchronise a sonography image and the MR image with multiplanar reconstruction (MPR) of the same section in real time. The aim of our study is to review the literature concerning the second look performed with this emerging and promising technique, showing both advantages and limitations in comparison with conventional targeted US.

Ultrasound Imaging Technologies for Breast Cancer Detection and Management: A Review

Ultrasound imaging is a commonly used modality for breast cancer detection and diagnosis. In this review, we summarize ultrasound imaging technologies and their clinical applications for the management of breast cancer patients. The technologies include ultrasound elastography, contrast-enhanced ultrasound, 3-D ultrasound, automatic breast ultrasound and computer-aided detection of breast ultrasound. We summarize the study results seen in the literature and discuss their future directions. We also provide a review of ultrasound-guided, breast biopsy and the fusion of ultrasound with other imaging modalities, especially magnetic resonance imaging (MRI). For comparison, we also discuss the diagnostic performance of mammography, MRI, positron emission tomography and computed tomography for breast cancer diagnosis at the end of this review. New ultrasound imaging techniques, ultrasound-guided biopsy and the fusion of ultrasound with other modalities provide important tools for the management of breast patients.

Clinical Value of Real-Time Ultrasonography-MRI Fusion Imaging for Second-Look Examination in Preoperative Breast Cancer Patients: Additional Lesion Detection and Treatment Planning

BACKGROUND

This study was conducted to evaluate the clinical effect of real-time magnetic resonance imaging (MRI)-navigated ultrasonography (US) for preoperative second-look examination in patients with breast cancer.

PATIENTS AND METHODS

Between October 2013 and February 2015, 232 patients with breast cancer underwent MRI for staging; second-look US was performed in 70 patients to evaluate additional lesions suspected to be disease detected using MRI. We retrospectively included 67 lesions in 55 patients. Lesions were classified as detected on conventional US (group 1), and not visible on conventional US, but detected on MRI-navigated US (group 2). The imaging features between groups 1 and 2 were compared using Student t, χ², or Fisher exact tests. We compared the detection rate and histopathology of additional lesions using a McNemar test.

RESULTS

Heterogeneous background echotexture (69.6% [16 of 23] vs. 34.1% [14 of 41]) and lesion isoechogenicity (65.2% [15 of 23] vs. 7.3% [3 of 41]) on US and middle or posterior lesion depth on MRI (78.3% [18 of 23] vs. 46.3% [19 of 41]) were more common in group 2 (P < .05). More lesions were detected using MRI-navigated US (64 of 67; 95.5%) than conventional US (41 of 67; 61.2%; P < .01). Using MRI-navigated US we found more high-risk or malignant lesions than conventional US (21 vs. 11; P < .01). The optimal treatment plan was determined for 9 of 16 (56.3%) patients by virtue of MRI-navigated US.

CONCLUSION

Real-time MRI-navigated US significantly improved the detection of additional high-risk or malignant lesions during second-look US in preoperative evaluation of patients with breast cancer and ultimately determined the optimal treatment plan.

MRI-guided breast interventions

Magnetic resonance imaging (MRI)-guided interventions, including biopsies and wire localizations, are fundamental to any breast imaging practice due to the high sensitivity but limited specificity of breast MRI. The basic steps of MRI-guided biopsies are similar regardless of the vendor or platform, and technical considerations include approach planning, patient preparation and positioning, lesion targeting, and directional sampling using a vacuum-assisted biopsy technique. Unique challenges related to MRI-guided biopsies include vanishing lesions due to contrast washout, obscuration of the biopsy site due to susceptibility artifacts, and limited access to posteromedial lesions. A careful approach to planning, patient positioning, and lesion targeting will maximize the chances for a successful biopsy. Due to overlapping imaging features between benign and malignant lesions, radiologic-pathologic concordance is difficult and essential for further patient management.

LEVEL OF EVIDENCE

5 Technical Efficacy: Stage 3 J. MAGN. RESON. IMAGING 2017;46:631-645.

Volume Navigation Technique for Ultrasound-Guided Biopsy of Breast Lesions Detected Only at MRI

OBJECTIVE

The purpose of this study is to assess the utility of a volume navigation technique (VNT) for ultrasound-guided biopsy of MRI-detected, but sonographically ambiguous or occult, breast lesions.

SUBJECTS AND METHODS

Within a recruitment period of 13 months (January 1, 2014, through February 1, 2015), 22 patients with 26 BI-RADS category 4 or 5 lesions that were detected at MRI but missed at second-look ultrasound were reimaged using a rapid sequence and a flexible body coil in a 3-T MRI scanner. Patients were supine, with three skin markers placed on the breasts. MRI volume data were coregistered to real-time ultrasound in a dedicated platform, and MRI-detected lesions (six masses, 11 nonmass enhancements, eight foci, and one architectural distortion) were sought using VNT-guided ultrasound. Five needle biopsy specimens were obtained either from each sonographically detected lesion (n = 11) or from VNT-guided sonographically localized breast volume corresponding to the MRI-detected, but still ultrasound-occult, lesions (n = 15).

RESULTS

Histopathologic analysis revealed 18 benign and six malignant lesions. The remaining two lesions, both of which appeared as masses at MRI, were high risk and were upgraded to carcinoma after excisional biopsy. All malignant lesions underwent curative surgery; the final histopathologic diagnoses remained unchanged. Of the six malignant lesions, one was a mass, three were nonmass enhancements, and two were enhancing foci at MRI. Three malignant lesions were occult at ultrasound, and three were discerned as subtle hypoechoic changes. No benign lesion was sonographically visualized as a mass, and none progressed, with 56% disappearing at MRI performed during the follow-up period (mean, 14 months).

CONCLUSION

Coregistration of MRI and real-time ultrasound enables sonographic localization of breast lesions detected at MRI only. VNT is a feasible alternative to MRI-guided biopsy of ultrasound-occult breast lesions.

Clinical Utility of Real-Time MR-Navigated Ultrasound with Supine Breast MRI for Suspicious Enhancing Lesions Not Identified on Second-Look Ultrasound

This study evaluated the usefulness of magnetic resonance (MR)-navigated ultrasound (US) for evaluation of magnetic resonance imaging (MRI)-detected lesions not visible on second-look US and analyzed differences in lesion-to-nipple distance between supine and prone positions. Of the 831 consecutive patients who were diagnosed with breast cancer and examined with breast MRI from June 2013 to September 2015, 40 lesions in 37 patients who underwent MR-navigated US for MRI-detected lesions that were not visible on second-look US were included. First, MRI was performed in a prone position using a 1.5-T imager, and second, MRI was performed in a supine position for MR-navigated US. Of 40 lesions, 31 (78%) were identified with MR-navigated US, whereas 5 (13%) lesions disappeared on supine MRI and 4 (10%) exhibited no correlation on MR-navigated US. Of 31 lesions with pathologic confirmation, 7 (23%) were malignant, 2 (6%) were high-risk lesions and 22 (71%) were benign lesions. Comparison of the US findings of benign and malignant lesions revealed that orientation of the lesion differed significantly (p = 0.045), whereas lesion shape, margin and echo pattern did not significantly differ between the two groups (p = 0.088, p = 0.094 and p = 0.412, respectively). Median difference in lesion-to-nipple distance on supine and prone MRI was 8 mm (0-34 mm) in the horizontal direction and 5 mm (0-39.5 mm) in the vertical direction. Thirteen lesions exhibited a >1-cm difference in both horizontal and vertical directions. In conclusion, MR-navigated US was useful for the evaluation of MRI-detected lesions that were not visible on second-look US in breast cancer patients.

The Potential Use of Ultrasound-Magnetic Resonance Imaging Fusion Applications in Musculoskeletal Intervention

We sought to assess the potential use of an application allowing real-time ultrasound spatial registration with previously acquired magnetic resonance imaging in musculoskeletal procedures. The ultrasound fusion application was used to perform a range of outpatient procedures including piriformis, sacroiliac joint, pudendal and intercostal nerve perineurial injections, hamstring-origin calcific tendonopathy barbotage, and 2 soft tissue biopsies at our institution in 2015. The application was used in a total of 7 procedures in 7 patients, all of which were technically successful. The ages of patients ranged from 19 to 86 years. Particular use of the fusion application compared to sonography alone was noted in the biopsy of certain soft tissue lesions and in perineurial therapeutic injections.

Real-Time MRI Navigated Ultrasound for Preoperative Tumor Evaluation in Breast Cancer Patients: Technique and Clinical Implementation

Real-time magnetic resonance imaging (MRI) navigated ultrasound is an image fusion technique to display the results of both MRI and ultrasonography on the same monitor. This system is a promising technique to improve lesion detection and analysis, to maximize advantages of each imaging modality, and to compensate the disadvantages of both MRI and ultrasound. In evaluating breast cancer stage preoperatively, MRI and ultrasound are the most representative imaging modalities. However, sometimes difficulties arise in interpreting and correlating the radiological features between these two different modalities. This pictorial essay demonstrates the technical principles of the real-time MRI navigated ultrasound, and clinical implementation of the system in preoperative evaluation of tumor extent, multiplicity, and nodal status in breast cancer patients.

Clinical value of relative quantification ultrasound elastography in characterizing breast tumors

OBJECTIVES

To evaluate ultrasound elastography (USE) using strain ratio (SR), a relative quantification approach for breast lesions characterization.

METHODS

One hundred forty-seven consecutive patients with a total of 156 breast lesions underwent USE. Technical accuracy was assessed automatically. For SR evaluation a rounded ROI was depicted inside fat (F), glandular tissue (G) and inside the lesion (L), preferably at the same depth. R1, mean value of the G and F ratio, stands for in background tissue composition elasticity. R2; mean value of L/F stands for in lesion elasticity, both evaluated in arbitrary unit (au). Two-years follow-up and pathology results were standard of reference. Mann-Whitney test, ROC analysis and Chi-square with Yates correction were used.

RESULTS

With the exception of 27 cysts, 17 malignant and 112 benign lesions were found. R1 values were 1.6±0.7au and 1.2±0.9au (p=0.015 NS); R2 values were 6.1±2.5au and 1.9±1.3au (p<0.001) for malignant and benign lesions, respectively. A threshold of 3.3au showed a sensitivity and specificity of 88% and 87%, respectively with an AUC of 93%. Fifteen false positive and two false negative were detected.

CONCLUSION

Relative quantification of ultrasound elastography allows to find high levels of diagnostic accuracy in characterizing breast tumors above all in downgrading BI-RADS 3 and 4 lesions.