Real-time virtual sonography (RVS)-guided vacuum-assisted breast biopsy for lesions initially detected with breast MRI

Clinical application of vein visualization apparatus AccuVein®500 in breast cancer surgery: a case report

BACKGROUND

AccuVein® can help visualize superficial veins and is generally used as an auxiliary device to identify patterns of veins that are difficult to locate for collecting blood and securing venous lines. Even when venous patterns are obscure via visual inspection and/or palpation, the clear projection/delineation of superficial veins using this apparatus facilitates safe venous puncture and helps secure venous lines. Therefore, this apparatus is widely used in clinical settings. AccuVein® can easily visualize not only superficial veins in the limbs but also the ones located throughout the body surface.

CASE PRESENTATION

We report three cases of 68-year-old, 41-year-old, and 56-year-old Japanese women in whom superficial veins in the breasts were visualized using AccuVein®, and mastectomy and partial mastectomy were performed. All patients were of Japanese ethnicity. AccuVein® can enable the examiner to observe superficial veins in the breasts, irrespective of their skills. The examiner can, thus, secure detailed visualization of subcutaneous veins in the breasts. Furthermore, AccuVein® ensures reproducibility and subjectivity regardless of the examiners' experience. During a mastectomy, the perforating branches of the internal thoracic vein originating from the greater pectoral muscle are identified, ligated, and separated. The preoperative use of AccuVein® makes it possible to instantaneously identify their position. Visualizing the perforating branches to their root in patients with thin subcutaneous breast fat and their roots' proximity in patients with thick subcutaneous breast fat is possible. While the position and/or range of a breast cancer lesion may sometimes be unclear in ultrasonography, marking subcutaneous mammary veins around the lesion as the benchmark helps identify the lesion position. In this study, we inspected the patterns of subcutaneous mammary veins using AccuVein®. This manuscript reports the clinical application of this apparatus in breast cancer surgeries.

CONCLUSION

Understanding the vascular construction of subcutaneous mammary veins using the vein visualization apparatus AccuVein® may serve as an auxiliary technique for safely and securely identifying breast cancer lesions.

Evaluation of the intramammary distribution of breast lesions detected by MRI but not conventional second-look B-mode ultrasound using an MRI/ultrasound fusion technique

The objective of this study was to evaluate the intramammary distribution of MRI-detected mass and focus lesions that were difficult to identify with conventional B-mode ultrasound (US) alone. Consecutive patients with lesions detected with MRI but not second-look conventional B-mode US were enrolled between May 2015 and June 2023. Following an additional supine MRI examination, we performed third-look US using real-time virtual sonography (RVS), an MRI/US image fusion technique. We divided the distribution of MRI-detected mammary gland lesions as follows: center of the mammary gland versus other (superficial fascia, deep fascia, and atrophic mammary gland). We were able to detect 27 (84%) of 32 MRI-detected lesions using third-look US with RVS. Of these 27 lesions, 5 (19%) were in the center of the mammary gland and 22 (81%) were located in other areas. We were able to biopsy all 27 lesions; 8 (30%) were malignant and 19 (70%) were benign. Histopathologically, three malignant lesions were invasive ductal carcinoma (IDC; luminal A), one was IDC (luminal B), and four were ductal carcinoma in situ (low-grade). Malignant lesions were found in all areas. During this study period, 132 MRI-detected lesions were identified and 43 (33%) were located in the center of the mammary gland and 87 (64%) were in other areas. Also, we were able to detect 105 of 137 MRI-detected lesions by second-look conventional-B mode US and 38 (36%) were located in the center of the mammary gland and 67 (64%) were in other areas. In this study, 81% of the lesions identified using third-look US with RVS and 64% lesions detected by second-look conventional-B mode US were located outside the center of the mammary gland. We consider that adequate attention should be paid to the whole mammary gland when we perform third-look US using MRI/US fusion technique.

Non-mass lesions on breast ultrasound: why does not the ACR BI-RADS breast ultrasound lexicon add the terminology?

The definition of a non-mass lesion on breast ultrasound (US) is designed for everyday practice to provide unambiguous clinical management and to assist physicians and sonographers as they interpret breast US images. The field of breast imaging research requires consistent and standardized terminology for non-mass lesions identified on breast US, especially when differentiating benign from malignant lesions. Physicians and sonographers should be aware of the benefits and limitations of the terminology and use them precisely. I am hopeful that the next edition of the Breast Imaging Reporting and Data System (BI-RADS) lexicon will include standardized terminology for describing non-mass lesions detected on breast US.

A review of MRI (CT)/US fusion imaging in treatment of breast cancer

The ultrasound fusion imaging system is a diagnostic device developed in Japan that utilizes ultrasound and magnetic positioning/navigation. A position sensor with a probe reads spatial location information from a magnetic field generator and by synchronously displaying ultrasound images and magnetic resonance (MR)/computed tomography (CT) images in real time. Lesions that are difficult to observe via ultrasonography alone, such as non-mass enhancement, can be identified. Furthermore, lesions that are difficult to identify with ultrasound alone indicated for MRI-guided biopsy under the National Health Insurance Scheme can be identified using ultrasound fusion technology, thereby enabling tissue biopsy to be performed under ultrasound guidance. Using this ultrasound fusion technology, not only non-mass enhancement but also small lesions that are difficult to identify using ultrasound alone can be detected, thus ensuring that a more accurate preoperative imaging diagnosis is established, and leading to safer, more reassuring examinations and surgical procedures. In this paper, we outline the use of this ultrasound fusion technology and fusion techniques in the treatment of breast cancer.

Evaluation of an MRI/US fusion technique for the detection of non-mass enhancement of breast lesions detected by MRI yet occult on conventional B-mode second-look US

PURPOSE

The aim of this study was to verify the utility of second-look ultrasound (US) using real-time virtual sonography (RVS), a magnetic resonance imaging (MRI)/US fusion technique, in identifying MRI-detected breast lesions with non-mass enhancement (NME).

METHODS

Consecutive patients who had one or more NME lesions detected by MRI yet occult on the subsequent second-look US in conventional B (cB)-mode imaging were enrolled in the study between June 2015 and April 2020. Supine MRI of the lesions was performed and, using its data, second-look US using RVS was performed.

RESULTS

Twenty patients with 21 NME lesions were included. The overall median lesion size on prone MRI was 23 mm (range, 5-63 mm). Supine MRI identified all the 21 NME lesions, and second-look US using RVS successfully detected 18 (86%) of them. RVS-guided biopsy was performed for histopathological evaluation, showing that nine of the 18 lesions were benign and the other nine malignant. Of the nine malignant lesions, two (22%) were invasive cancer and seven (78%) were ductal carcinoma in situ. In four of five patients who underwent prone MRI for preoperative evaluation, the diagnosis was benign and surgery was conducted as originally planned. In the other patient, the diagnosis was malignant and contralateral breast-conserving surgery was added. Three (14%) of the 21 NME lesions had no RVS correlates and were judged to be benign after 24-month follow-up.

CONCLUSION

The results suggest that second-look US using RVS helps identify MRI-detected NME lesions that are occult on cB-mode second-look US.

Simulation and navigation liver surgery: an update after 2,000 virtual hepatectomies

The advent of preoperative 3-dimensional (3D) simulation software has made a variety of unprecedented surgical simulations possible. Since 2004, we have performed more than 2,000 preoperative simulations in the University of Tokyo Hospital, and they have enabled us to obtain a great deal of information, such as the detailed shape of liver segments, the precise volume of each segment, and the volume of hepatic venous drainage areas. As a result, we have been able to perform more aggressive and complicated surgery safely. The next step is to create a navigation system that will accurately reproduce the preoperative plan. Real-time virtual sonography (RVS) is a navigation system that provides fusion images of ultrasonography and reconstructed computed tomography images or magnetic resonance images. The RVS system facilitates the surgeon's understanding of interpretation of ultrasound images and the detection of tumors that are difficult to find by ultrasound alone. In the near future, surgical navigation systems may evolve to the point where they will be able to inform surgeons intraoperatively in real time about not only intrahepatic structures, such as vessels and tumors, but also the portal territory, hepatic vein drainage areas, and resection lines that have been planned preoperatively.

Quantitative Assessment of the Accuracy of Real-Time Virtual Sonography for Liver Surgery

Background. Real-time virtual sonography (RVS) is a navigation system for liver surgery. In this study, the degree of misalignment of intraoperative RVS images with computed tomographic (CT) images was measured. Methods. Between December 2014 and July 2015, intraoperative RVS was performed in a total of 33 patients undergoing liver surgery. Reconstructed CT images, rendered like intraoperative ultrasonographic (IOUS) images, were adjusted with the IOUS images and visualized side by side. The degree of misalignment between the reconstructed CT images and IOUS images was measured at anterior section, posterior section, and left liver in each patient. Furthermore, the time required for the adjustment was measured as the "adjustment time." Results. The degree of misalignment between the images could potentially be measured for a total of 96 points in the 33 patients. Of these, the actual measurement could not be conducted for 35 points due to poor visualization of the intrahepatic vasculature (n = 20) or to a large misalignment that hampered continuation of further adjustment (n = 15). The median degree of misalignment was 9.8 mm (range = 2.4-37.6 mm) in the right anterior section, 9.8 mm (range = 2.7-71.5 mm) in the right posterior section, and 9.5 mm (range = 0.9-37.6 mm) in the left liver. The median adjustment time was 105 seconds (range = 51-245 seconds). Conclusions. Although some misalignment occurred, it might be acceptable for selected situations. Further investigation is needed to reduce the frequency of adjustment failure.

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.

Pre-Operative Planning Using Real-Time Virtual Sonography, an MRI/Ultrasound Image Fusion Technique, for Breast-Conserving Surgery in Patients with Non-Mass Enhancement on Breast MRI: A Preliminary Study

The purpose of this retrospective study was to evaluate the effect of pre-operative planning using real-time virtual sonography (RVS), a magnetic resonance imaging (MRI)/ultrasound (US) image fusion technique on breast-conserving surgery (BCS) in patients with non-mass enhancement (NME) on breast MRI. Between 2011 and 2015, we enrolled 12 consecutive patients who had lesions with NME that exceeded the US hypo-echoic area, in which it was particularly difficult to evaluate the tumor margin. During pre-operative planning before breast-conserving surgery, RVS was used to delineate the enhancing area on the breast surface after additional supine breast MRI was performed. We analyzed both the surgical margin positivity rate and the re-operation rate. All NME lesions corresponded to the index cancer. In all patients, the diameter of the NME lesion was greater than that of the hypo-echoic lesion. The median diameters of the NME and hypo-echoic lesions were 24 mm (range: 12-39 mm) and 8.0 mm (range: 4.9-18 mm), respectively (p = 0.0002). After RVS-derived skin marking was performed on the surface of the affected breast, lumpectomy and quadrantectomy were conducted in 7 and 5 patients, respectively. The surgical margins were negative in 10 (83%) patients. Two patients with positive margins were found to have ductal carcinoma in situ in 1 duct each, 2.4 and 3.2 mm from the resection margin, respectively. None of the patients required additional resection. Although further prospective studies are required, the findings of our preliminary study suggest that it is very well possible that the use of RVS-derived skin marking during pre-operative planning for BCS in patients with NME would have resulted in surgical outcomes similar to or better than those obtained without the use of such marking.

Predictive detection areas for identifying additional MRI-detected breast lesions on second-look ultrasonography

PURPOSE

Identifying an additional MRI-detected breast lesion on second-look ultrasonography (US) is technically challenging because of lesion displacement with the patient's position change. The aim of this study is to help identify MRI-detected lesions on second-look US by developing a probing area, called "the predictive detection area" (PDA), and by assessing the PDA.

METHODS

We measured the nipple-to-lesion distances (NLDs) for 16 breast lesions on prone- and supine-position MRI sets and calculated the difference and angle between the two NLD vectors, representing the lesion displacement. The minimum and maximum differences and angles were chosen to form the PDA. Another 22 breast lesions, detected in the prone MRI, were identified on US by probing the PDA to evaluate the probability of existence.

RESULTS

The width between the minimum and maximum differences in two NLDs and the angle to form the PDA for the upper-inner, upper-outer, and lower-outer quadrants were 23.0 mm and 95.0°, 29.0 mm and 41.0°, and 18.0 mm and 17.0°, respectively. The respective probabilities of existence were 100, 80, and 100%.

CONCLUSIONS

The PDA had a high probability of existence and was acceptably accurate; therefore, the PDA in a second-look US has the potential to help operators to quickly identify additional MRI-detected lesions.

Real-time virtual sonography examination and biopsy for suspicious breast lesions identified on MRI alone

OBJECTIVES

The purpose of our study was to assess whether there is a potential additional value of real-time virtual sonography (RVS) to second-look ultrasound (US) examination and biopsy for breast lesions identified on MRI alone.

METHODS

A retrospective review of the records of 70 consecutive patients (78 lesions) with breast abnormalities identified on MRI alone was performed. All suspicious enhancing lesions were subsequently evaluated with second-look US. Lesions not observed on second-look US underwent RVS. Pathological findings were confirmed by subsequent percutaneous biopsy or excision.

RESULTS

Of the 78 MRI-detected lesions, second-look US correlation was made in 50 (64 %), including 22 malignant and 28 benign lesions. The remaining 28 lesions (36 %) were scheduled to undergo RVS. Four lesions were not visible on the second breast MRI. The remaining 24 lesions were RVS correlated and underwent RVS-guided biopsy; these included seven malignant and 17 benign lesions. Overall, 74 of 74 (100 %) true MRI-detected lesions were confirmed by histological results without using MRI-guided breast biopsy. The cancer rate was 29 %.

CONCLUSIONS

RVS can increase the sonographic detection and biopsy rate of lesions identified on breast MRI alone.

KEY POINTS

• All 74 MRI-detected lesions were confirmed without using MRI-guided biopsy. • Four lesions were not visible on second breast MRI. • RVS can increase sonographic detection of lesions identified on breast MRI alone. • RVS-guided breast biopsy can be an alternative to MRI-guided biopsy.

Targeted sonography using an image fusion technique for evaluation of incidentally detected breast lesions on chest CT: a pilot study

BACKGROUND

With increasing use of computed tomography (CT), incidentally detected breast lesions are being encountered more frequently. The aim of our study was to verify the utility of targeted sonography using an image fusion technique, real-time virtual sonography (RVS) that coordinates real-time sonography images with previously obtained CT images using a magnetic position tracking system, for evaluation of incidentally detected breast lesions on chest CT.

METHODS

Eleven lesions in 11 women with no history of breast cancer who were referred to our unit for assessment of breast lesions incidentally detected on CT were enrolled in this study. To assess the efficacy of targeted sonography using RVS, we analyzed the frequency of sonographic detection of incidentally detected breast lesions and the difference between sonography- and CT-determined diameters.

RESULTS

Using RVS guidance, all 11 lesions were sonographically detected. Ten (91 %) of 11 lesions underwent sonography-guided biopsy, yielding a success rate of 90 % (9/10). The remaining sonography-guided biopsy failure lesion required surgical biopsy for definitive diagnosis; this was performed after RVS was used to mark CT imaging information onto the breast surface. Four (36 %) lesions subsequently proved to be malignant. The mean diameters provided by RVS were 14.9 ± 6.7 mm for sonography and 16.8 ± 7.5 mm for CT (p = 0.538).

CONCLUSION

Using RVS, a sonographic probe was precisely guided to the lesions. Our results suggest that targeted sonography using RVS is a useful technique for identifying incidentally detected breast lesions on chest CT.

Prediction of prone-to-supine tumor displacement in the breast using patient position change: investigation with prone MRI and supine CT

BACKGROUND

One of the challenges for clinical use of preoperative breast magnetic resonance imaging (MRI) is how to transfer prone MRI information to the operating theater with a supine surgical position. The aim of this study was to retrospectively evaluate tumor displacement in the breast by changing the patient position from prone to supine (prone-to-supine tumor displacement), using preoperative prone MRI and supine computed tomography (CT).

METHODS

Preoperatively, 55 Japanese women with 57 breast cancer lesions underwent breast MRI in the prone position and breast CT in the supine position. Tumor positions in both the prone and supine positions were measured on X-, Y-, and Z-coordinates by fixing the nipple to the origin (0, 0, 0). As an indicator of the mobility of the breast, the ratio of the breast projection between the prone MRI and supine CT (prone-to-supine projection ratio) was calculated. The direction and distance of prone-to-supine tumor displacement was analyzed by dividing the breast into four quadrants according to the tumor position.

RESULTS

When changing the patient position from prone to supine, tumors located in the inner-upper and inner-lower quadrants tended to move radially toward the center of the nipple. The movement distance of the tumors in the inner-lower and outer-lower quadrants was very strongly correlated with the prone-to-supine breast projection ratio (r ≥ 0.8, p < 0.05). Conversely, in the outer-upper quadrant, the direction of tumor displacement was variable, and the distance of tumor displacement did not correlate with the prone-to-supine projection ratio.

CONCLUSIONS

The present study showed that prone-to-supine tumor displacement in the breast differs depending on tumor location. The inner-lower quadrant of the breast may be the most predictable area for prone-to-supine tumor displacement.