Breast Sentinel Lymph Node Navigation With Three-Dimensional Interstitial Multidetector-Row Computed Tomographic Lymphography

Recent advancement of imaging strategies of the lymphatic system: Answer to the decades old questions

The role of the lymphatic system in maintaining tissue homeostasis and a number of different pathophysiological conditions has been well established. The complex and delicate structure of the lymphatics along with the limitations of conventional imaging techniques make lymphatic imaging particularly difficult. Thus, in-depth high-resolution imaging of lymphatic system is key to understanding the progression of lymphatic diseases and cancer metastases and would greatly benefit clinical decisions. In recent years, the advancement of imaging technologies and development of new tracers suitable for clinical applications has enabled imaging of the lymphatic system in both clinical and pre-clinical settings. In this current review, we have highlighted the advantages and disadvantages of different modern techniques such as near infra-red spectroscopy (NIRS), positron emission tomography (PET), computed tomography (CT), magnetic resonance imaging (MRI) and fluorescence optical imaging, that has significantly impacted research in this field and has led to in-depth insights into progression of pathological states. This review also highlights the use of current imaging technologies, and tracers specific for immune cell markers to identify and track the immune cells in the lymphatic system that would help understand disease progression and remission in immune therapy regimen.

Imaging features of sentinel lymph node mapped by multidetector-row computed tomography lymphography in predicting axillary lymph node metastasis

INTRODUCTION

Accurately assessing axillary lymph node (ALN) status in breast cancer is vital for clinical decision making and prognosis. The purpose of this study was to evaluate the predictive value of sentinel lymph node (SLN) mapped by multidetector-row computed tomography lymphography (MDCT-LG) for ALN metastasis in breast cancer patients.

METHODS

112 patients with breast cancer who underwent preoperative MDCT-LG examination were included in the study. Long-axis diameter, short-axis diameter, ratio of long-/short-axis and cortical thickness were measured. Logistic regression analysis was performed to evaluate independent predictors associated with ALN metastasis. The prediction of ALN metastasis was determined with related variables of SLN using receiver operating characteristic (ROC) curve analysis.

RESULTS

Among the 112 cases, 35 (30.8%) cases had ALN metastasis. The cortical thickness in metastatic ALN group was significantly thicker than that in non-metastatic ALN group (4.0 ± 1.2 mm vs. 2.4 ± 0.7 mm, P < 0.001). Multi-logistic regression analysis indicated that cortical thickness of > 3.3 mm (OR 24.53, 95% CI 6.58-91.48, P < 0.001) had higher risk for ALN metastasis. The best sensitivity, specificity, negative predictive value(NPV) and AUC of MDCT-LG for ALN metastasis prediction based on the single variable of cortical thickness were 76.2%, 88.5%, 90.2% and 0.872 (95% CI 0.773-0.939, P < 0.001), respectively.

CONCLUSION

ALN status can be predicted using the imaging features of SLN which was mapped on MDCT-LG in breast cancer patients. Besides, it may be helpful to select true negative lymph nodes in patients with early breast cancer, and SLN biopsy can be avoided in clinically and radiographically negative axilla.

Sentinel lymph node biopsy in breast cancer guided by CT lymphography; History, evolution and current applications

Sentinel lymph node biopsy (SLNB) has efficiently replaced axillary lymph node dissection (ALND) in axillary staging in node-negative breast cancer patients. Dual sentinel lymph node (SLN) localization using radioisotopes and blue dye is the standard technique for SLN mapping. Yet, nuclear medicine facilities are not widely available worldwide. In Japan, Computed tomography lymphography (CTLG) is presented as an SLN mapping technique which was first suggested in 2003 by Suga et al. Multiple subsequent studies confirmed the efficacy of CTLG in SLN mapping in breast cancer. Further applications of the technique followed; such as prediction of SLN metastasis using CTLG, the use of CTLG guided SLN biopsy after neoadjuvant therapy, video-assisted CTLG guided SLN biopsy, the use of real-time virtual sonography with 3-D CTLG, and preoperative localization of the CTLG mapped SLN using either real-time virtual sonography (RVS) guided Indocyanine green (ICG) injection or its marking using liquid charcoal and silver wire and the use of SPIO enhanced magnetic resonance imaging (MRI) for prediction of metastasis in SLNs detected by CTLG. This efficacy and variable applications open the door for conducting wide-scale randomized controlled trials to suggest using CTLG as an efficient alternative for the use of radioisotopes in SLN mapping in breast cancer patients, especially in low and middle-income countries.

Real-Time Visualization of Lymphatic Flow to Sentinel Lymph Nodes by Contrast-Enhanced Ultrasonography with Sonazoid in Patients with Breast Cancer

Contrast-enhanced ultrasonography with Sonazoid (SNZ) enables real-time visualization, resulting in more precise identification of lymphatic flow to sentinel lymph nodes (SLNs). This study aimed to classify lymphatic drainage patterns to SLNs. Patients (n = 75) with T1-2 N0 M0 breast cancer received a periareolar injection of SNZ to identify SNZ-enhanced SLNs (SNZ-SLNs), followed by SLN biopsy with blue dye. The lymphatic drainage patterns were classified into four types: type A, single lymphatic route/single SLN; type B, multiple lymphatic routes/single SLN; type C, single lymphatic route/multiple SLNs; and type D, multiple lymphatic routes/multiple SLNs. SLNs were successfully identified in all patients using both blue dye and SNZ. The drainage lymphatic pathways identified were as follows: type A in 53 cases (70.7%), type B in seven (9.3%), type C in eight cases (10.7%) and type D in seven (9.3%). SNZ-SLN biopsy is a technically simple method with a 100% identification rate, enabling the real-time visualization of lymphatic flow to SNZ-SLNs.

Computerized evaluation scheme to detect metastasis in sentinel lymph nodes using contrast-enhanced computed tomography before breast cancer surgery

Sentinel lymph node (SLN) biopsy for evaluating lymph node metastasis during breast cancer surgery is associated with several problems, such as the consequent increase in operation time and the possibility of abrupt changes in the treatment plan during the operation. Although it is desirable to distinguish SLNs with and without cancer metastasis before surgery, there is no established examination for this purpose. This study aimed to develop a computerized scheme for evaluating metastasis in SLNs by analyzing computed tomography lymphography images and the three-dimensional versions of these images. Our database consisted of computed tomography lymphography images from 100 patients with breast cancer. Three subjective features of the nodes were assessed in the three-dimensional images: (1) the shape of the lymphoduct, (2) degree of signal enhancement in the nodes, and (3) shape of the nodes. Six objective features were also assessed in the computed tomography lymphography images: (4) the long axis, (5) area, (6) standard deviation of the signal values, (7) mean signal values, (8) maximum signal value, and (9) minimum signal value. Support vector machines were employed to evaluate cancer metastasis in SLNs. For the input, six of the nine features were selected in a stepwise method. The classification accuracy, sensitivity, and specificity were 98.0% (98/100), 97.8% (44/45), and 98.2% (54/55), respectively. The positive and negative predictive values were 97.8% (44/45) and 98.2% (54/55), respectively. This computerized method exhibited high classification accuracy and will be useful in determining the need for lymph node dissection before breast cancer surgery.

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.

Real-time lymphography by indocyanine green fluorescence: improved navigation for regional lymph node staging

OBJECTIVES

Lymphatic imaging is an important step for the identification of lymphonodal positive disease in solid malignancies. Various methods have been established to detect positive lymph nodes, but the available diagnostic tools leave some inherent drawbacks. The aim of this study was to validate the indocyanine green (ICG) guided approach for transcutaneous and transmesenterial navigation with accurate lymph vessel and node identification for regional lymph node staging in solid malignancies.

METHODS

After institutional review board approval, a planar fluorescence imaging system was applied for lymphography and lymph node detection using ICG. A total of 96 patients were recruited and subject to fluorescence navigation for axillary (n = 46), inguinal (n = 16), and mesenterial (n = 34) visualization to analyze technical and clinical feasibility of the method after regional lymph node dissection and the applicability.

RESULTS

Overall fluorescence imaging identified lymphatic vessels and the SLN in 92 out of 96 patients (detection rate: 96%) after a mean injection of 7 mg ICG. Sensitivity based on fluorescent emission of ICG navigation was 95.6% in 65 out of 68 patients with lymph node dissection. All solid tumors were feasible for fluorescence-guided navigation with a broad spectrum.

CONCLUSION

Fluorescence-guided real-time lymphography with navigation to regional lymph nodes enables accurate visualization for a broad spectrum of different solid tumors with potential lymphonodal spread. In addition, the technique can be applied for lymphography in non-malignant diseases. With reference to the broad application spectrum, institutional investment in camera equipment can be justified.

Preoperative diagnosis of sentinel lymph node (SLN) metastasis using 3D CT lymphography (CTLG)

BACKGROUND

Sentinel lymph node biopsy (SLNB) became a standard procedure for patients with early breast cancer, however, an indication of SLN navigation to metastatic disease may lead to misdiagnosis for staging. Preoperative CTLG with a water-soluble iodinated contrast medium visualizes the correct primary SLNs and its afferent lymphatic channels surrounding detailed anatomy, therefore it can predict LN metastasis by visualizing the lymph vessel obstruction or stain defect of the SLN by tumor. The current study presents the value of CTLG for preoperative prediction for SLN status.

METHODS

A total of 228 patients with Tis-T2 breast cancer who did not receive primary chemotherapy were studied. SLN metastasis was diagnosed according to the following staining patterns of SLNs and afferent lymphatic vessels: stain defect of SLN, obstruction, stagnation, dilation, and detour of the lymphatic vessels by tumor occupation. The diagnosis was compared with the pathological results to evaluate the accuracy of prediction for SLN metastasis using CTLG.

RESULTS

Twenty-seven of 228 patients had metastatic SLN pathologically. Twenty-five of these were diagnosed as metastatic preoperatively. The accuracy for metastatic diagnosis using CTLG was 89.0%, sensitivity was 92.6%, and specificity was 88.6%. The positive predictive value was 52.1% and negative predictive value was 98.8%.

CONCLUSION

CTLG can select the candidate with truly node negative cases in early breast cancer patients, because it predicts lymph node metastasis preoperatively from natural status of the lymphographic image. It also might omit the SLN biopsy itself.

Breast sentinel lymph node navigation with three-dimensional computed tomography-lymphography: a 12-year study

PURPOSE

To evaluate the utility of three-dimensional (3D) computed tomography (CT)-lymphography (LG) breast sentinel lymph node navigation in our institute.

PATIENTS AND METHODS

Between 2002 and 2013, we preoperatively identified sentinel lymph nodes (SLNs) in 576 clinically node-negative breast cancer patients with T1 and T2 breast cancer using 3D CT-LG method. SLN biopsy (SLNB) was performed in 557 of 576 patients using both the images of 3D CT-LG for guidance and the blue dye method.

RESULTS

Using 3D CT-LG, SLNs were visualized in 569 (99%) of 576 patients. Of 569 patients, both lymphatic draining ducts and SLNs from the peritumoral and periareolar areas were visualized in 549 (96%) patients. Only SLNs without lymphatic draining ducts were visualized in 20 patients. Drainage lymphatic pathways visualized with 3D CT-LG (549 cases) were classified into four patterns: single route/single SLN (355 cases, 65%), multiple routes/single SLN (59 cases, 11%) single route/multiple SLNs (62 cases, 11%) and multiple routes/multiple SLNs (73 cases, 13%). SLNs were detected in 556 (99.8%) of 557 patients during SLNB.

CONCLUSION

CT-LG is useful for preoperative visualization of SLNs and breast lymphatic draining routes. This preoperative method should contribute greatly to the easy detection of SLNs during SLNB.

Sentinel node mapping of VX2 carcinoma in rabbit thigh with CT lymphography using ethiodized oil

OBJECTIVE

To assess the feasibility of computed tomography (CT) lymphography using ethiodized oil for sentinel node mapping in experimentally induced VX2 carcinoma in the rabbit thigh.

MATERIALS AND METHODS

This experiment received approval from the institutional animal use and care administrative advisory committee. Twenty-three rabbits with VX2 carcinoma in the thigh underwent CT before and after (1 hour, 2 hour) peritumoral injection of 2 mL ethiodized oil. After the CT examination, sentinel nodes were identified by peritumoral injection of methylene blue and subsequently removed. The retrieved sentinel and non-sentinel lymph nodes were investigated with radiographic and pathologic examinations. Based on the comparison of CT findings with those of radiographic and pathologic examinations, the diagnostic performance of CT for sentinel node identification was assessed.

RESULTS

All 23 rabbits showed 53 ethiodized oil retention nodes on post-injection CT and specimen radiography, and 52 methylene blue-stained nodes at the right femoroiliac area. Of the 52 blue-stained sentinel nodes, 50 nodes demonstrated ethiodized oil retention. Thus, the sentinel node detection rate of CT was 96% (50 of 52). On pathologic examination, 28 sentinel nodes in 17 rabbits (nodes/rabbit, mean ± standard deviation, 1.7 ± 0.6) harbored metastasis. Twenty seven of the 28 metastatic sentinel nodes were found to have ethiodized oil retention.

CONCLUSION

Computed tomography lymphography using ethiodized oil may be feasible for sentinel node mapping in experimentally induced VX2 carcinoma in the rabbit thigh.

A dual-modal magnetic nanoparticle probe for preoperative and intraoperative mapping of sentinel lymph nodes by magnetic resonance and near infrared fluorescence imaging

The ability to reliably detect sentinel lymph nodes for sentinel lymph node biopsy and lymphadenectomy is important in clinical management of patients with metastatic cancers. However, the traditional sentinel lymph node mapping with visible dyes is limited by the penetration depth of light and fast clearance of the dyes. On the other hand, sentinel lymph node mapping with radionucleotide technique has intrinsically low spatial resolution and does not provide anatomic details in the sentinel lymph node mapping procedure. This work reports the development of a dual modality imaging probe with magnetic resonance and near infrared imaging capabilities for sentinel lymph node mapping using magnetic iron oxide nanoparticles (10 nm core size) conjugated with a near infrared molecule with emission at 830 nm. Accumulation of magnetic iron oxide nanoparticles in sentinel lymph nodes leads to strong T2 weighted magnetic resonance imaging contrast that can be potentially used for preoperative localization of sentinel lymph nodes, while conjugated near infrared molecules provide optical imaging tracking of lymph nodes with a high signal to background ratio. The new magnetic nanoparticle based dual imaging probe exhibits a significant longer lymph node retention time. Near infrared signals from nanoparticle conjugated near infrared dyes last up to 60 min in sentinel lymph node compared to that of 25 min for the free near infrared dyes in a mouse model. Furthermore, axillary lymph nodes, in addition to sentinel lymph nodes, can be also visualized with this probe, given its slow clearance and sufficient sensitivity. Therefore, this new dual modality imaging probe with the tissue penetration and sensitive detection of sentinel lymph nodes can be applied for preoperative survey of lymph nodes with magnetic resonance imaging and allows intraoperative sentinel lymph node mapping using near infrared optical devices.

Early gastric cancer: feasibility of CT lymphography with ethiodized oil for sentinel node mapping

PURPOSE

To evaluate the feasibility of CT lymphography with ethiodized oil for sentinel node mapping in porcine stomachs and in patients with early gastric cancer.

MATERIALS AND METHODS

Approval for the animal study was obtained from the authors' institutional animal use and care administrative advisory committee, the clinical study was approved by the institutional review board, and informed consent was obtained from each participant. Five pigs underwent CT lymphography 1 hour after gastric subserosal injection of 1 mL ethiodized oil and sentinel node mapping with injection of 1 mL methylene blue. Ethiodized oil retention nodes were identified on the radiographic images of the gastric specimen and removed for histopathologic examination. In addition, 10 patients with early gastric cancer underwent CT lymphography with peritumoral injection of 1 mL ethiodized oil, followed by sentinel basin extirpation with CT and routine nodal dissection. The removed sentinel basins were examined by radiography. Histopathologic examination was performed for dissected nodes, including sentinel nodes.

RESULTS

In each of the five pigs, CT showed one perigastric ethiodized oil retention node. After harvesting the ethiodized oil retention node, blue-stained areas were identified in the five removed nodes and intranodal ethiodized oil was detected on histopathologic examination. In all 10 patients, CT lymphography with ethiodized oil successfully defined the sentinel basin with ethiodized oil retention nodes. CT lymphography revealed 20 ethiodized oil retention nodes. After basin extirpation, 28 and 46 nodes were detected on radiographic and histopathologic examinations. Histopathologic examination revealed that one patient had micrometastases at two sentinel nodes and another patient had isolated tumor cells at one sentinel node. No patient had metastasis in nonsentinel nodes.

CONCLUSION

CT lymphography with ethiodized oil may be a feasible method for sentinel node mapping in patients with early gastric cancer.

An experimental study to evaluate the Fluobeam 800 imaging system for fluorescence-guided lymphatic imaging and sentinel node biopsy

BACKGROUND

Visualization of the lymphatic system is challenging. Lymphatic imaging is a crucial diagnostic tool for benign and malignant lymphatic pathologies. Fluorescence-guided imaging allows selective lymphatic mapping and sentinel lymph node (SLN) identification. There are a few fluorescence systems, but some drawbacks remain due to technical and ergonomic aspects. The aim of this study was to evaluate the feasibility of the new Fluobeam 800 imaging system.

METHODS

After approval by the ethics committee, the system was evaluated for lymphography and SLN biopsy in an animal model. Five pigs each with 4 lymph node (LN) stations (n = 20 LN stations) were subjected to lymphatic imaging using indocyanine green (ICG). Additionally, the use of ICG was compared with ICG adsorbed to human serum albumin (ICG-HSA). Lymphatic vessels and SLN identification rates were measured.

RESULTS

After injection, a clear fluorescence signal of the lymphatic vessels was visualized leading to the LN station. Overall, ICG fluorescence imaging identified a mean of 2.0 lymphatic vessels and 1.1 (range = 1-2) SLN in 20 of 20 LN stations. Reverse lymphography was feasible. A clinical difference in resolution was not detected between use of ICG-HSA and ICG.

CONCLUSION

This is the first study analyzing the feasibility of the Fluobeam 800 imaging system allowing transcutaneous real-time imaging. It enables detection of the SLN by fluorescence retention with increased detection depth and resolution. After fixation to the ceiling, the ergonomics advanced for simultaneous field navigation and dissection. The new system can be applied for lymphatic imaging for lympatico-reconstructive surgery and SLN biopsy.

Lymphatic mapping with fluorescence navigation using indocyanine green and axillary surgery in patients with primary breast cancer

The indocyanine green fluorescence (ICGf) navigation method provides real-time lymphatic mapping and sentinel lymph node (SLN) visualization, which enables the removal of SLNs and their associated lymphatic networks. In this study, we investigated the features of the drainage pathways detected with the ICGf navigation system and the order of metastasis in axillary nodes. From April 2008 to February 2010, 145 patients with clinically node-negative breast cancer underwent SLN surgery with ICGf navigation. The video-recorded data from 79 patients were used for lymphatic mapping analysis. We analyzed 145 patients with clinically node-negative breast cancer who underwent SLN surgery with the ICGf navigation system. Fluorescence-positive SLNs were identified in 144 (99%) of 145 patients. Both single and multiple routes to the axilla were identified in 47% of cases using video-recorded lymphatic mapping data. An internal mammary route was detected in 6% of the cases. Skip metastasis to the second or third SLNs was observed in 6 of the 28 node-positive patients. We also examined the strategy of axillary surgery using the ICGf navigation system. We found that, based on the features of nodal involvement, 4-node resection could provide precise information on the nodal status. The ICGf navigation system may provide a different lymphatic mapping result than computed tomography lymphography in clinically node-negative breast cancer patients. Furthermore, it enables the identification of lymph nodes that do not accumulate indocyanine green or dye adjacent to the SLNs in the sequence of drainage. Knowledge of the order of nodal metastasis as revealed by the ICGf system may help to personalize the surgical treatment of axilla in SLN-positive cases, although additional studies are required.

Magnetic resonance lymphography of sentinel lymph nodes in patients with breast cancer using superparamagnetic iron oxide: a feasibility study

BACKGROUND

The sentinel lymph node (SLN) biopsy technique using superparamagnetic iron oxide (SPIO) as a tracer instead of radioisotopes has been described. To further advance this technique, we evaluated preoperative SPIO-MR sentinel lymphography to facilitate the accurate identification of the lymphatic pathways and primary SLN.

METHODS

A prospective study was performed in ten patients with breast cancer and clinically negative axillary lymph nodes. None of the patients received preoperative chemotherapy. After 1.6 ml of SPIO (ferucarbotran) was injected in the subareolar breast tissue, sentinel axillary lymph nodes were detected by MRI in T2*-weighted gradient echo images and resected using the serial SPIO-SLN biopsy procedure with a handheld magnetometer.

RESULTS

In one patient, gadolinium-enhanced MR imaging was performed at the same time as SPIO-MR lymphography, and this patient was excluded from further analysis. In all patients (9/9) SLNs were detected by SPIO-MR sentinel lymphography and successfully identified at surgery. The number of SLNs detected by lymphography (mean 2.7) significantly correlated with SLNs identified at surgery (mean 2.2). One patient had nodal metastases. In one patient, skin color changed to brown at the injection site and resolved spontaneously. There were no severe reactions to the procedure or complications in any patient.

CONCLUSIONS

This is the first study to evaluate SPIO both as a contrast material in MR sentinel lymphography and as a tracer in SLN biopsy using an integrated method. The acquired three-dimensional imaging demonstrated excellent image quality and usefulness to identify SLN in conjunction with SLN biopsy.

Preclinical lymphatic imaging

Noninvasive in vivo imaging of lymphatic vessels and lymphatic nodes is expected to fulfill the purpose of analyzing lymphatic vessels and their function, understanding molecular mechanisms of lymphangiogenesis and lymphatic spread of tumors, and utilizing lymphatic molecular markers as a prognostic or diagnostic indicator. In this review, we provide a comprehensive summary of in vivo imaging modalities for detecting lymphatic vessels, lymphatic drainage, and lymphatic nodes, which include conventional lymphatic imaging techniques such as dyes and radionuclide scintigraphy as well as novel techniques for lymphatic imaging such as optical imaging, computed tomography, magnetic resonance imaging, ultrasound, positron emission tomography using lymphatic biomarkers, photoacoustic imaging, and combinations of multiple modalities. The field of lymphatic imaging is ever evolving, and technological advances, combined with the development of new contrast agents, continue to improve the research of lymphatic vascular system in health and disease states as well as to improve the accuracy of diagnosis in the relevant diseases.

Diagnosis of breast cancer with multidetector computed tomography: analysis of optimal delay time after contrast media injection

PURPOSE

The aim of this study was to investigate the optimal delay time after a contrast media injection for multidetector computed tomography (MD-CT) images in the diagnosis of breast cancer patients.

MATERIALS AND METHODS

Thirty-one patients who underwent MD-CT for their preoperative examination and who had postoperatively confirmed pathology were enrolled. Four-phase images of dynamic contrast enhanced study were acquired using four-detector MDCT. All cases were mammographically classified into two groups according to BI-RADS: nondense and dense groups. The CT value of the background mammary gland, background breast enhancement (BBE), and tumor-background mammary gland contrast (TBC) were compared between the two groups.

RESULTS

The CT value of the dense group was significantly higher than that of the nondense group in all phases. BBE in both nondense and dense groups showed no significant differences in any of the phases. In the nondense group, TBC was significantly higher in both the second and the third phases than in the first phase, while in the dense group, TBC was significantly higher in the second phase than in the first and third phases.

CONCLUSION

The optimal delay time to depict breast cancer is 80 s after a contrast media injection, regardless of the density level of the background mammary gland.

Evaluation of sentinel lymph node metastasis alone guided by three-dimensional computed tomographic lymphography in video-assisted breast surgery

BACKGROUND

Detailed relations between lymph nodes and lymph flow can be clarified by three-dimensional computed tomographic (3D-CT) lymphangiography. Systematic collection of lymph nodes based on 3D-CT lymphangiography can decrease unnecessary lymph node dissection and attendant complications.

METHODS

To mark the sentinel lymph node (SLN) on the skin, 3D-CT lymphangiography was performed the day before the surgery. Iopamiron 300 (2 ml) was injected subcutaneously. A 16-channel multidetector-row helical CT scan image was reconstructed to produce a 3D image of lymph ducts and lymph nodes. Biopsy of SLN was performed by a dye-staining method using Visiport-aided endoscopy. Stained lymph nodes were located by following the dye in the lymph ducts on a video monitor. For SLN-metastasis-positive patients, standard axillary lymph node dissection (levels 1 and 2) was performed with video assistance.

RESULTS

Since December 2001, video-assisted breast surgery has been performed for 180 patients, SLN biopsy for 150 patients, and 3D-CT lymphangiography for 110 patients. Findings show that SLN-positive metastasis (n = 31) was accompanied by SLN metastasis alone in 14 patients. One-node metastasis, except for SLN, was observed in seven patients, two-node metastasis in three patients, and metastasis involving more than three nodes in seven patients. Review of the lymphoid path using 3D-CT lymphangiography confirmed that metastasis occurred in order of lymph flow.

CONCLUSIONS

Absence of metastasis in the second and third SLNs, even in patients with SLN metastasis, obviates the need for dissection of more nodes.

Development of a macromolecular dual-modality MR-optical imaging for sentinel lymph node mapping

OBJECTIVE

To evaluate the effectiveness of a dual magnetic resonance-near infrared fluorescence optical imaging agent, poly(l-glutamic acid)-DTPA-Gd-NIR813, for both preoperative and intraoperative visualization and characterization of sentinel lymph nodes (SLN) in mice.

MATERIALS AND METHODS

Poly(L-glutamic acid) was conjugated with DTPA-Gd and NIR813 dye to obtain PG-DTPA-Gd-NIR813. To confirm drainage into the SLNs, this agent was injected subcutaneously into the front paw of nude mice followed by isosulfan blue (n = 6). Furthermore, PG-DTPA-Gd-NIR813 was injected subcutaneously at doses of 0.002 mmol Gd/kg (4.8 nmol eq. NIR813) and 0.02 mmol Gd/kg (48 nmol eq. NIR813) (n = 3/dose). To differentiate metastatic from nonmetastatic lymph nodes, nude mice bearing human oral squamous cell carcinoma (DM14) were injected intralingually with 0.02 mmol Gd/kg PG-DTPA-Gd-NIR813 (n = 3). Pre- and postcontrast images were taken using 4.7 T Bruker MRI scanner and Xenogen optical imaging system. The status of lymph nodes resected under the guidance of optical imaging was confirmed by histologic examinations.

RESULTS

PG-DTPA-Gd-NIR813 colocalized with isosulfan blue, indicating drainage to the SLN. After subcutaneous injection, axiliary and branchial lymph nodes were clearly visualized with both T1-weighted MR and optical imaging within 3 minutes of contrast injection, even at the lowest dose tested (0.002 mmol Gd/kg). After intralingual injection in tumor-bearing mice, MR imaging identified 4 of the 6 superficial cervical lymph nodes, whereas near-infrared fluorescence (NIRF) optical imaging identified all 6 cervical nodes. The pattern of contrast enhancement of SLN visualized in MR images showed a characteristic ring-shaped appearance with a central filling defect, possibly resulting from nodal infiltration of metastatic lesions. Histopathologic examination of the SLNs resected under NIRF imaging guidance revealed micrometastases in all 6 SLNs identified by NIRF imaging.

CONCLUSIONS

The dual modality imaging method demonstrated in this study represents an effective technique for localization and characterization of SLN.

Sentinel lymph node biopsy for breast cancer

This manuscript is a brief discussion of the developments of the technology and concepts that led to modern procedures of radiotracer guided surgery of sentinel nodes (SNs) for breast cancer. The past section highlights some of the contributions by key persons involved with SN methods. The present section describes the magnitude of types of published material to date. The future section describes the major international trials and some important technical challenges yet to be solved.

Video-assisted breast surgery and sentinel lymph node biopsy guided by three-dimensional computed tomographic lymphography

BACKGROUND

Video-assisted breast surgery (VABS) is a less invasive and aesthetically better option for benign and malignant breast diseases and for sentinel lymph node biopsy (SLNB). The authors have performed 150 VABS procedures since December 2001. They have examined the usefulness of three-dimensional computed tomographic (3D-CT) lymphography for detecting sentinel lymph nodes (SLNs) precisely, as well as the cosmetic and treatment results of VABS.

METHODS

In this study, VABS was performed with a 2.5-cm skin incision in the axilla or periareola (1 cm in the axilla for SLNB), using a retraction method, for mammary gland resection, SLNB, axillary lymph node dissection, and breast reconstruction under video assistance. On the day before the surgery, 3D-CT lymphography was performed to mark SLN on the skin. Above the tumor and near the areola, 2 ml of Iopamiron 300 was injected subcutaneously. A 16-channnel multidetector-row helical CT scan image was taken after 1 min and reconstructed to produce a 3D image. Sentinel lymph node biopsy was performed by the VABS technique using the Visiport.

RESULTS

The VABS procedure was performed for 19 benign and 131 malignant diseases, and 115 SLNBs (74 with 3D-CT) were performed. The SLNs were shown precisely by 3D-CT lymphography, as proved by a case of lymph node metastasis, in which accurate relationships between lymph ducts and SLNs were shown. These were classified into four patterns: a single duct to single node (40 cases), multiple ducts to a single node (13 cases), a single duct to multiple nodes (1 case), and multiple ducts to multiple nodes (12 cases). The SLNB procedure can be performed safely by 3D-CT lymphography and less invasively by VABS.

CONCLUSIONS

The findings show that 3D-CT lymphography is useful for performing precise SLNB using VABS.

Current status of sentinel lymph node navigation surgery in breast and gastrointestinal tract

Sentinel lymph node biopsy (SLNB) has been developed as a new diagnostic and therapeutic modality in melanoma and breast cancer surgery. The purpose of the SLNB include preventing the operative morbidity and improving the pathologic stage by focusing on fewer lymph nodes using immunocytochemic and molecular technology has almost achieved in breast cancer surgery. The prognostic meaning of immunocytochemically detected micrometastases is also evaluating in the SLN and bone marrow aspirates of women with early-stage breast cancer. SLNB using available techniques have suggested that the lymphatic drainage of the gastrointestinal tract is much more complicated than other sites, skip metastasis being rather frequent because of an aberrant lymphatic drainage outside of the basin exist. At the moment, the available data does not justify reduced extent of lymphadenectomy, but provides strong evidence for an improvement in tumor staging on the basis of SLNB. Two large scale prospective multi-center trials concerning feasibility of gamma-probe and dye detection for gastric cancer are ongoing in Japan. Recent studies have shown favorable results for identification of SLN in esophageal cancer. CT lymphography with endoscopic mucosal injection of iopamidol was applicable for SLN navigation of superficial esophageal cancer. The aim of surgical treatment is complete resection of the tumor-infiltrated organ including the regional lymph nodes. Accurate detection of SLN can achieve a selection of a more sophisticated tailor made approach. The patient can make a individualized choice from a broader spectrum of therapeutic options including endoscopic, laparoscopic or laparoscopy-assisted surgery, modified radical surgery, and typical radical surgery with lymph node dissection. Ultrastaging by detecting micrometastasis at the molecular level and the choice of an adequate treatment improve the postoperative quality of life and survival. However these issues require further investigation.

Radiofrequency ablation therapy for small breast cancer followed by immediate surgical resection or delayed mammotome excision

BACKGROUND

There is increasing demand for minimally invasive treatment approaches. Although radiofrequency (RF) ablation therapy is promising for the local treatment of small, well-localized breast cancer, the problem of determining tumor cell death after RF ablation remains.

METHODS

In the first series of this study, 17 patients underwent surgical resection immediately after RF ablation and 7 patients received delayed mammotome excision in the second series. The ablated tumor tissue was examined histologically with hematoxylin-eosin (H&E) staining and nicotinamide adenine dinucleotide (NADH)-diaphorase staining to assess tumor cell viability.

RESULTS

Histological examination with H&E staining revealed a spectrum of changes ranging from complete coagulation necrosis to normal-appearing tumor cells, although the degenerative changes were more remarkable in the second than in the first series. However, NADH-diaphorase staining revealed no viable tumor cells in the ablated lesion in either series.

CONCLUSIONS

NADH-diaphorase staining is essential to assess the effects of RF ablation. However, further studies are needed to determine whether RF ablation may provide equivalent local control and survival compared with conventional BCT for patients with small breast cancer.

Lymphography of the Thoracic Duct by Percutaneous Injection of Iohexol into the Popliteal Lymph Node of Dogs: Experimental Study and Clinical Application

OBJECTIVE

To evaluate the efficacy of percutaneous administration of iohexol into the popliteal lymph node as a non-invasive technique for thoracic duct lymphangiography in dogs.

STUDY DESIGN

Experimental study and clinical report.

ANIMALS

Normal adult dogs (n=4) and 1 dog with recurrent chylothorax.

METHODS

For the experimental study, 4 dogs (weight, 8.4-12.3 kg) had 5-10 mL iohexol injected percutaneously into 1 popliteal lymph node and then thoracic radiographs were taken. Popliteal lymph nodes were examined by histopathology 8 days later. One 25-kg dog with recurrent chylothorax had 25 mL iohexol injected into the right popliteal lymph node followed by thoracic radiography.

RESULTS

In experimental dogs, the thoracic duct was best visualized on thoracic radiographs after administration of 10 mL iohexol. Clinically, no abnormalities were identified in the injected limb and except for 1 dog that had large numbers of siderocytes and erythrophagocytic macrophages in the injected lymph node, the histopathologic findings in the other injected popliteal lymph nodes were not different from contralateral nodes. In the clinical case, the thoracic duct was visualized, but there was leakage of iohexol around the node.

CONCLUSION

The thoracic duct in dogs can be visualized by lymphography after percutaneous injection of iohexol (1 mL/kg at 2 mL/min) into the popliteal lymph node.

CLINICAL RELEVANCE

Percutaneous popliteal lymph node administration of iohexol should be considered as an alternative to mesenteric lymph node injection for radiographic identification of the thoracic duct in dogs.

Using the intraoperative hand held probe without lymphoscintigraphy or using only dye correlates with higher sensory morbidity following sentinel lymph node biopsy in breast cancer: a review of the literature

BACKGROUND

There are no studies that have directly investigated the incremental reduction in sensory morbidity that lymphoscintigraphy images (LS) and triangulated body marking or other skin marking techniques provide during sentinel lymph node biopsy (SLNB) compared to using only the probe without LS and skin marking or using only dye. However, an indirect assessment of this potential for additional sensory morbidity reduction is possible by extracting morbidity data from studies comparing the morbidity of SLNB to that of axillary lymph node dissection.

METHODS

A literature search yielded 13 articles that had data on sensory morbidity at specific time points on pain, numbness or paresthesia from SLNB that used radiotracer and probe or used only dye as a primary method of finding the sentinel node (SN). Of these, 10 utilized LS, while 3 did not utilize LS. By matching the data in studies not employing LS to the studies that did, comparisons regarding the percentage of patients experiencing pain, numbness/paresthesia after SLNB could be reasonably attempted at a cutoff of 9 months.

RESULTS

In the 7 studies reporting on pain after 9 months (> 9 months) that used LS (1347 patients), 13.8% of patients reported these symptoms, while in the one study that did not use LS (143 patients), 28.7% of patients reported these symptoms at > 9 months (P < 0.0001). In the 6 studies reporting on numbness and/or paresthesia at > 9 months that used LS (601 patients), 12.5% of patients reported these symptoms, while in the 3 studies that did not use LS (229 patients), 23.1% of patients reported these symptoms at > 9 months (P = 0.0002). Similar trends were also noted for all these symptoms at < or = 9 months.

CONCLUSION

Because of variations in techniques and time of assessing morbidity, direct comparisons between studies are difficult. Nevertheless at a minimum, a clear trend is present: having the LS images and skin markings to assist during SLNB appears to yield more favorable morbidity outcomes for the patients compared to performing SLNB with only the probe or performing SLNB with dye alone. These results are extremely pertinent, as the main reason for performing SLNB itself in the first place is to achieve reduced morbidity.