Use of sentinel node lymphoscintigraphy in malignant melanoma

Revolutionizing lymph node metastasis imaging: the role of drug delivery systems and future perspectives

The deployment of imaging examinations has evolved into a robust approach for the diagnosis of lymph node metastasis (LNM). The advancement of technology, coupled with the introduction of innovative imaging drugs, has led to the incorporation of an increasingly diverse array of imaging techniques into clinical practice. Nonetheless, conventional methods of administering imaging agents persist in presenting certain drawbacks and side effects. The employment of controlled drug delivery systems (DDSs) as a conduit for transporting imaging agents offers a promising solution to ameliorate these limitations intrinsic to metastatic lymph node (LN) imaging, thereby augmenting diagnostic precision. Within the scope of this review, we elucidate the historical context of LN imaging and encapsulate the frequently employed DDSs in conjunction with a variety of imaging techniques, specifically for metastatic LN imaging. Moreover, we engage in a discourse on the conceptualization and practical application of fusing diagnosis and treatment by employing DDSs. Finally, we venture into prospective applications of DDSs in the realm of LNM imaging and share our perspective on the potential trajectory of DDS development.

More than Just Skin-Deep: A Review of Imaging's Role in Guiding CAR T-Cell Therapy for Advanced Melanoma

Advanced melanoma is one of the deadliest cancers, owing to its invasiveness and its propensity to develop resistance to therapy. Surgery remains the first-line treatment for early-stage tumors but is often not an option for advanced-stage melanoma. Chemotherapy carries a poor prognosis, and despite advances in targeted therapy, the cancer can develop resistance. CAR T-cell therapy has demonstrated great success against hematological cancers, and clinical trials are deploying it against advanced melanoma. Though melanoma remains a challenging disease to treat, radiology will play an increasing role in monitoring both the CAR T-cells and response to therapy. We review the current imaging techniques for advanced melanoma, as well as novel PET tracers and radiomics, in order to guide CAR T-cell therapy and manage potential adverse events.

Bi-modal near-infrared fluorescence and ultrasound imaging via a transparent ultrasound transducer for sentinel lymph node localization

Sentinel lymph node biopsy with an indocyanine green-based near-infrared fluorescence imaging system avoids the shortcomings of using a radioisotope or a combination of a blue dye and a radioactive tracer. To improve surgical precision, recent research has provided a depth profile of the sentinel lymph node by fusing fluorescence and ultrasound imaging. Here, we present a combined near-infrared fluorescence and ultrasound imaging system based on a transparent ultrasound transducer. The transparent ultrasound transducer enables seamless coaxial alignment of the fluorescence and ultrasound beam paths, allowing bi-modal observation of a single region of interest. Further, we demonstrate that the sentinel lymph node of mice injected with indocyanine green can be successfully localized and dissected based on information from the bi-modal imaging system.

Lymphoscintigraphic Mapping in Melanoma and Breast Cancer

In determining the best options for lymphoscintigraphy, investigators have tried many different radiopharmaceuticals and protocols. There are varying opinions on the best route of administration, timing for delayed images, and radiopharmaceutical. Debate around which radiopharmaceutical is best arises from the requirement that it clear from healthy lymph channels quickly enough to reveal the SLN. This paper reviews and compares 9 recognized publications on lymphoscintigraphy, illustrates the different preferences regarding the procedure, and describes the generally accepted protocols for the best way to locate the sentinel lymph node. Detailed explanations are given for the variable involvement of the sentinel lymph node and the variations in disease stage seen with different protocols. All discrepancies between protocols are supported with evidence such as positive results or false-positive results. On reading this paper, you will be able to form an opinion on the best protocols and radiopharmaceuticals and learn why lymphoscintigraphy is a crucial tool in improving a patient's prognosis.

Stage Two Malignant Melanoma of the Clitoris: A Case Report

Mucosal melanomas are rare in comparison to cutaneous melanomas, accounting for approximately 1% of all melanoma cases. Vulvovaginal melanoma is the least common mucosal melanoma subtype. For patients without distant metastases at presentation, regional lymph node involvement is the most important prognostic indicator. Lymphoscintigraphy is a method used to identify the sentinel lymph node (SLN), directing subsequent biopsies to the lymph node at highest risk for cancer spread. We present a 67-year-old Hispanic female with stage II B (T4aN0M0) melanoma of the clitoris. The patient initially sought medical treatment for a pigmented vulvar lesion over her clitoris that occasionally bleeds. She stated that over the past month the lesion began to grow peripherally and then acquired a very dark color. The patient underwent local excision of the mass and subsequent pathology revealed malignant melanoma. The patient underwent lymphoscintigraphy which allowed localization and subsequent biopsy of the left inguinal sentinel node. The left inguinal sentinel node was negative for metastatic melanoma. It was opted to keep her under observation. Compared to cutaneous melanoma, patients with mucosal melanoma usually present with more advanced disease, and thus efficacious imaging practices play a significant role in the management of the disease. Lymphoscintigraphy is a well-tolerated, validated, cost-effective, and reliable method of detecting sentinel nodes with minimal radiation exposure to the patient. In our case, early clinical detection allowed for prompt surgical intervention, pathologic diagnosis, and reliable staging via lymphoscintigraphy of a rare form of malignant melanoma.

Subdermal Ultrasound Contrast Agent Injection for Sentinel Lymph Node Identification: An Analysis of Safety and Contrast Agent Dose in Healthy Volunteers

OBJECTIVES

Mapping of the lymphatic chain for identification of the sentinel lymph node (SLN) is an important aspect of predicting outcomes for patients with breast cancer, and it is usually performed as an intraoperative procedure using blue dye and/or radiopharmaceutical agents. Recently, the use of contrast-enhanced ultrasound (CEUS) has been proposed as an alternative imaging technique for this mapping. The objective of this study was to evaluate the use of subdermal administration of the ultrasound (US) contrast agent Sonazoid (GE Healthcare, Oslo, Norway) in terms of patient safety and to select the dose to be used for lymphatic applications in humans.

METHODS

This study was performed in 12 female volunteers who received bilateral subdermal injections of Sonazoid (1 or 2 mL dose) in the mid-upper outer quadrant of their breasts at 2 different time points. Contrast-enhanced US examinations were performed 0, 0.25, 0.5, 1, 2, 4, 6, and 24 hours after injection to identify SLNs.

RESULTS

Sentinel lymph nodes were identified within the first hour after injection as enhanced structures, and there was no significant difference by dose in the number of SLNs identified (P = .74). The volunteers only had minor adverse experiences (AEs) that resolved completely without intervention by study completion.

CONCLUSIONS

The subdermal use of Sonazoid in this study showed only minor local and nonsignificant AEs that were completely resolved without any intervention. Two different doses were compared with no significant differences observed between them. Hence, the lower dose studied (1 mL) was selected for use in future clinical studies.

Reliability and Accuracy of Sentinel Node Biopsy in Cutaneous Malignant Melanoma

Aims and Background

The aims of this study were 1) to investigate whether sentinel lymph node (SLN) biopsy could become the method of choice for the early detection of metastatic disease in patients with malignant melanoma and 2) to identify those patients with lymph node metastases who could benefit from regional lymphadenectomy.

Methods and Study Design

Our study started in March 1998 and involved 110 patients with primary cutaneous malignant melanoma stage I or II (AJCC) in whom the primary lesion had been surgically removed no more than 90 days previously. On the day of lymph node dissection patients were given an intradermal injection of colloid particles of human serum albumin labeled with technetium-99m and an injection of isosulfan blue. The surgical procedure was usually performed with local anesthesia but in some cases locoregional or general anesthesia was preferred. Contralateral and ipsilateral lymphatic areas were scanned with a hand-held gamma camera (Scintiprobe MR 100) to measure the background and identify the hot point indicating the location of the sentinel node to direct the incision.

Results

The combined use of lymphoscintigraphy, isosulfan blue and gamma probe allowed us to identify sentinel nodes in 108 of 110 patients (98.18%) while the SLN was blue in only 90 cases (81.81%). The SLN was positive for metastases in 13 of the 108 patients (12.03%) and regional and distal lymphadenectomy was performed in all of them. The distribution of positive SLNs by primary lesion thickness was as follows: 0.76-1.5 mm: one positive SLN/44 patients (2.27%); 1.51-4 mm: six positive SLNs/51 patients (11.7%); >4 mm: six positive SLNs/15 patients (40%). Only four of 12 patients with ulcerated cutaneous melanoma had positive SLNs. The patients in our study underwent follow-up visits every four months. The median follow-up was 481 days (range, 97-1271 days).

Conclusions

In patients with primary cutaneous melanoma the histological status of the SLN accurately reflects the presence or absence of metastatic disease in the relevant regional lymph node basin. Complete lymph node dissection should only be performed in patients with positive SLNs. Patients with lesions >4 mm are likely to develop recurrences and to die of systemic disease, so in these patients the usefulness of SLN biopsy is questionable. In conclusion, sentinel node mapping is a rational approach for the selection of patients who might benefit from early lymph node dissection of the affected basin.

Intraoperative mapping of sentinel lymph node metastases using a clinically translated ultrasmall silica nanoparticle

The management of regional lymph nodes in patients with melanoma has undergone a significant paradigm shift over the past several decades, transitioning from the use of more aggressive surgical approaches, such as lymph node basin dissection, to the application of minimally invasive sentinel lymph node (SLN) biopsy methods to detect the presence of nodal micrometastases. SLN biopsy has enabled reliable, highly accurate, and low-morbidity staging of regional lymph nodes in early stage melanoma as a means of guiding treatment decisions and improving patient outcomes. The accurate identification and staging of lymph nodes is an important prognostic factor, identifying those patients for whom the expected benefits of nodal resection outweigh attendant surgical risks. However, currently used standard-of-care technologies for SLN detection are associated with significant limitations. This has fueled the development of clinically promising platforms that can serve as intraoperative visualization tools to aid accurate and specific determination of tumor-bearing lymph nodes, map cancer-promoting biological properties at the cellular/molecular levels, and delineate nodes from adjacent critical structures. Among a number of promising cancer-imaging probes that might facilitate achievement of these ends is a first-in-kind ultrasmall tumor-targeting inorganic (silica) nanoparticle, designed to overcome translational challenges. The rationale driving these considerations and the application of this platform as an intraoperative treatment tool for guiding resection of cancerous lymph nodes is discussed and presented within the context of alternative imaging technologies. WIREs Nanomed Nanobiotechnol 2016, 8:535-553. doi: 10.1002/wnan.1380 For further resources related to this article, please visit the WIREs website.

Contrast-enhanced sonography for detection of secondary lymph nodes in a melanoma tumor animal model

OBJECTIVES

To investigate the use of contrast-enhanced ultrasound imaging (US) for detection of secondary lymph nodes (LNs) in a naturally occurring melanoma swine model compared to surgery and pathologic assessment.

METHODS

Twenty-seven Sinclair swine were studied. The perfluorobutane microbubble contrast agent Sonazoid (GE Healthcare, Oslo, Norway) was administered (1.0 mL total dose) around the melanoma, and contrast-enhanced US was used to localize contrast-enhanced sentinel lymph nodes (SLNs). Then Sonazoid (dose, 0.25-1.0 mL) was injected into the SLNs to detect contrast-enhanced efferent lymphatic channels and secondary LNs. After peritumoral injection of blue dye, a surgeon (blinded to the contrast-enhanced US results) performed a radical LN dissection. Contrast-enhanced US was used to guide removal of any enhanced secondary LNs left after radical LN dissection. Clustered conditional logistic regression analyzed the benefit of contrast-enhanced US-directed secondary LN dissection over radical LN dissection using pathologic findings as the reference standard.

RESULTS

A total of 268 secondary LNs were resected, with 59 (22%) containing metastases. Contrast-enhanced US detected 92 secondary LNs; 248 were identified by radical LN dissection; and 68 were identified by both methods. Metastases were detected in 20% (51 of 248) and 40% (37 of 92) of the secondary LNs identified by radical LN dissection and contrast-enhanced US, respectively. Thus, secondary LNs detected by contrast-enhanced US were nearly 5 times more likely to contain metastases than secondary LNs removed by radical LN dissection (odds ratio, 4.8; P < .0001). Twenty-two of the 180 secondary LNs (12%) identified only by radical LN dissection contained metastases, whereas contrast-enhanced US identified 20 secondary LNs after the surgeon completed the radical LN dissection, of which 8 (40%) contained metastases.

CONCLUSIONS

Secondary LNs can be detected by using contrast-enhanced US after injection of Sonazoid into SLNs. Secondary LNs detected with contrast-enhanced US are significantly more likely to contain metastases than those removed by radical LN dissection.

Clinically-translated silica nanoparticles as dual-modality cancer-targeted probes for image-guided surgery and interventions

Early diagnosis and treatment of melanoma are essential to minimizing morbidity and mortality. The presence of lymph node metastases is a vital prognostic predictor, and accurate identification by imaging has important implications for disease staging, prognosis, and clinical outcome. Sentinel lymph node (SLN) mapping procedures are limited by a lack of intraoperative visualization tools that can aid accurate determination of disease spread and delineate nodes from adjacent critical neural and vascular structures. Newer methods for circumventing these issues can exploit a variety of imaging tools, including biocompatible particle-based platforms coupled with portable device technologies for use with image-guided surgical and interventional procedures. We describe herein a clinically-translated, integrin-targeting platform for use with both PET and optical imaging that meets a number of key design criteria for improving SLN tissue localization and retention, target-to-background ratios, and clearance from the site of injection and the body. The use of such agents for selectively probing critical cancer targets may elucidate important insights into cellular and molecular processes that govern metastatic disease spread. Coupled with portable, real-time optical camera systems, we show that pre-operative PET imaging findings for mapping metastatic disease in clinically-relevant larger-animal models can be readily translated into the intraoperative setting for direct visualization of the draining tumor lymphatics and fluorescent SLN/s with histologic correlation. The specificity of this platform, relative to the standard-of-care radiotracer, (18)F-FDG, for potentially discriminating metastatic disease from inflammatory processes is also discussed in the setting of surgically-based or interventionally-driven therapies.

Altered drainage patterns in patients with melanoma and previous axillary dissection

The incidence of melanoma is increasing rapidly in the United States. Sentinel lymph node biopsy is an important diagnostic tool in the treatment and staging of melanoma. However, many patients with melanoma will have had lymph node surgery for previous melanoma or breast cancer. We set out to examine alterations in drainage patterns in patients with previous axillary dissection for breast cancer. We reviewed four patients with truncal and/or extremity melanomas and examined their lymphoscintigraphy and drainage patterns. Three patients with truncal melanoma mapped to cervical lymph nodes and a fourth patient with an arm melanoma mapped to her previously dissected axilla. Sentinel lymph node mapping is still an important adjunct in patients with melanoma despite previous axillary dissection.

Contrast-enhanced ultrasound imaging of sentinel lymph nodes after peritumoral administration of Sonazoid in a melanoma tumor animal model

OBJECTIVES

The purpose of this study was to compare lymphosonography (ie, contrast-enhanced ultrasound imaging [US] after interstitial injection of a US contrast agent) for the detection of sentinel lymph nodes (SLNs) in swine with naturally occurring melanoma tumors to lymphoscintigraphy using blue dye-guided surgical dissection as the reference standard. Also, we sought to determine if lymphosonography can be used to characterize SLNs.

METHODS

Sixty-three swine with 104 melanomas were evaluated. Contrast-specific US was performed after peritumoral injection (1 mL dose) of Sonazoid (GE Healthcare, Oslo, Norway). Lymphoscintigraphy was performed after peritumoral injections of technetium Tc 99m sulfur colloid. Peritumoral injection of 1% Lymphazurin (Ben Venue Labs, Inc, Bedford, OH) was used to guide SLN resection. The accuracy of SLN detection with the two imaging modalities was compared using the McNemar test. The SLNs were qualitatively and quantitatively characterized as benign or malignant based on the lymphosonography results with histopathology and RNA analyses used as the reference standards.

RESULTS

Blue dye-guided surgery identified 351 SLNs. Lymphosonography detected 293 SLNs and 11 false-positives, while lymphoscintigraphy detected 231 SLNs and 20 false-positives. The accuracy of SLN detection was 81.8% for lymphosonography, which was significantly higher than the 63.2% achieved with lymphoscintigraphy (P < .0001). The accuracy of lymphosonography for SLN characterization was 80%. When the size of the enhanced SLN was taken into consideration to characterize SLNs, the accuracy was 86%.

CONCLUSIONS

Lymphosonography is statistically better than lymphoscintigraphy for the detection of SLNs in this animal model. The ability to use lymphosonography as a means to characterize SLNs as benign or malignant is limited.

Gray-scale contrast-enhanced ultrasonography of sentinel lymph nodes in a metastatic breast cancer model

RATIONALE AND OBJECTIVES

Previous studies showed it was possible to employ sonographic contrast agent for identification of the sentinel lymph nodes (SLNs). This study is to investigate the usefulness of SonoVue (a sonographic contrast agent) and gray-scale contrast-enhanced ultrasonography (CEUS) for detecting the SLNs in a metastatic breast cancer model.

MATERIALS AND METHODS

CEUS was performed in 12 female rabbits with breast VX2 tumor after subcutaneous administration of SonoVue. The site, number, and pattern of enhancement of the SLNs were observed and recorded. After CEUS, 0.5 mL of blue dye was injected into the same location as SonoVue and the SLNs were detected by surgical dissection. The findings of CEUS were compared with those of blue dye.

RESULTS

Of the 12 tumors assessed, a total of 17 enhanced SLNs were detected by CEUS. Among them, a single SLN was detected in eight tumors, two SLNs in three tumors, and three SLNs in one tumor. All the SLNs showed partial enhancement on CEUS. Nineteen SLNs were identified by blue dye with surgical dissection. There were no false-positive CEUS findings in terms of SLN detection. The overall sensitivity of CEUS for detecting SLNs was 89.5% (17/19). Among the 17 SLNs detected by CEUS, tumor metastases were identified histopathologically in 4 SLNs, whereas proliferation of lymphatic tissue was identified in the other 13 SLNs.

CONCLUSIONS

CEUS combined with SonoVue is useful for detecting SLNs, although it may not be helpful for detecting metastases in SLNs.

Gray-scale contrast-enhanced ultrasonography in detecting sentinel lymph nodes: an animal study

OBJECTIVE

To investigate the usefulness of gray-scale contrast-enhanced ultrasonography for detecting sentinel lymph nodes.

METHODS

Contrast-enhanced ultrasonography was performed in five normal dogs (four female and one male) after subcutaneous administration of a sonographic contrast agent (Sonovue, Bracco, Milan, Italy). Four distinct regions in each animal were examined. After contrast-enhanced ultrasonography, 0.8 ml of blue dye was injected into the same location as Sonovue and the sentinel lymph nodes were detected by surgical dissection. The findings of contrast-enhanced ultrasonography were compared with those of the blue dye.

RESULTS

Twenty-one sentinel lymph nodes were detected by contrast-enhanced ultrasonography while 23 were identified by blue dye with surgical dissection. Compared with the blue dye, the detection rate of enhanced ultrasonography for the sentinel lymph nodes is 91.3% (21/23). Two patterns of enhancement in the sentinel lymph nodes were observed: complete enhancement (5 sentinel lymph nodes) and partial enhancement (16 sentinel lymph nodes). The lymphatic channels were demonstrated as hyperechoic linear structures leading from the injection site and could be readily followed to their sentinel lymph nodes. Histopathologic examination showed proliferation of lymphatic follicles or lymphatic sinus in partial enhanced sentinel lymph nodes while normal lymphatic tissue was demonstrated in completely enhanced sentinel lymph nodes.

CONCLUSIONS

Sonovue combined with gray-scale contrast-enhanced ultrasonography may provide a feasible method for detecting sentinel lymph nodes.

Upper extremity lymphatic function at rest and during exercise in breast cancer survivors with and without lymphedema compared with healthy controls

Lymphoscintigraphy was used to measure lymphatic function at rest and during exercise in breast cancer survivors with lymphedema (BCRL, n = 10), breast cancer survivors (BC, n = 10), and controls (Cont, n = 10). After injection of 99mTc-antimony colloid to the hands, subjects rested or performed 12 repeated sets of arm cranking for 2.5 min at 0.6 W/kg followed by 2.5 min of rest. One-minute spot views were taken with a gamma-radiation camera immediately postinjection and every 10 min over 60 min to calculate clearance rate. As well, an upper body scan was taken at 65 min postinjection to measure radiopharmaceutical uptake in the axilla (Ax) and forearm (Fore). All groups displayed similar increases in clearance rate with exercise ( P = 0.000). Ax significantly increased with exercise in Cont only [Cont: (mean ± SD) 4.9 ± 2.6 vs. 7.9 ± 4.2%, P = 0.000; BCRL: 1.4 ± 1.2 vs. 1.7 ± 2.1%, P = 0.531; BC: 3.9 ± 3.4 vs. 5.2 ± 3.2%, P = 0.130], whereas Fore, indicating dermal backflow, significantly increased in BCRL only (BCRL: 2.4 ± 0.87 vs. 4.4 ± 2.0%, P = 0.004; BC: 1.1 ± 0.25 vs. 1.1 ± 0.31%, P = 0.784; Cont: 0.93 ± 0.26 vs. 1.0 ± 0.20%, P = 0.296). The results indicate that, in women with BCRL, exercise causes radiopharmaceuticals to clear from the hand at the same rate as BC and Cont, but, instead of reaching the axilla, a greater amount of activity gets trapped in the dermis of the forearm. BC, meanwhile, have similar lymphatic function as Cont; however, there is a highly variable response that may suggest that some BC subjects may be at risk for developing lymphedema.

Canine Oral Melanoma

Melanoma is the most common oral malignancy in the dog. Oral and/or mucosal melanoma has been routinely considered an extremely malignant tumor with a high degree of local invasiveness and high metastatic propensity. Primary tumor size has been found to be extremely prognostic. The World Health Organization staging scheme for dogs with oral melanoma is based on size, with stage I = <2-cm-diameter tumor, stage II = 2- to <4-cm-diameter tumor, stage III = > or = 4cm tumor and/or lymph node metastasis, and stage IV = distant metastasis. Median survival times for dogs with oral melanoma treated with surgery are approximately 17 to 18, 5 to 6, and 3 months with stage I, II, and III disease, respectively. Significant negative prognostic factors include stage, size, evidence of metastasis, and a variety of histologic criteria. Standardized treatments such as surgery, coarse-fractionation radiation therapy, and chemotherapy have afforded minimal to modest stage-dependent clinical benefits and death is usually due to systemic metastasis. Numerous immunotherapeutic strategies have been employed to date with limited clinical efficacy; however, the use of xenogeneic DNA vaccines may represent a leap forward in clinical efficacy. Oral melanoma is a spontaneous syngeneic cancer occurring in outbred, immunocompetent dogs and appears to be a more clinically faithful therapeutic model for human melanoma; further use of canine melanoma as a therapeutic model for human melanoma is strongly encouraged. In addition, the development of an expanded but clinically relevant staging system incorporating the aforementioned prognostic factors is also strongly encouraged.

Pearls and pitfalls of radionuclide imaging of the lymphatic system. Part 1: sentinel node lymphoscintigraphy in malignant melanoma

Radionuclide imaging of the lymphatic system has a major role in the management of two main patient groups. First, pre-operative lymphoscintigraphy is a highly accurate method of sentinel node localization and can help guide minimally invasive surgery in a variety of tumour groups. Second, lymphoscintigraphy can play a pivotal role in assessing the cause of extremity swelling. This is the first of two pictorial essays on radionuclide imaging of the lymphatic system and will focus on sentinel node imaging in malignant melanoma. Regional nodal sampling is routinely performed in an increasing number of tumour groups and is well established in malignant melanoma and breast carcinoma. Careful attention to technical performance and image interpretation is essential to maximize the clinical utility of the test. This article provides a pictorial review of the interpretative pearls and pitfalls of sentinel node lymphoscintigraphy in malignant melanoma patients.

Lymphoscintigraphy to Evaluate the Effect of High versus Low Intensity Upper Body Dynamic Exercise on Lymphatic Function in Healthy Females

BACKGROUND

Little is known about the acute effects of exercise on the lymphatic system. Thus, the purpose was to determine the effect of low versus high intensity upper body exercise on lymphatic function in healthy females.

METHODS AND RESULTS

On separate days, eight females performed either HI: 12 repeated sets of arm cranking for 2.5 min at 0.6 W.kg-1, followed by 2.5 min of rest; or LO: 12 repeated sets of arm cranking for 2.5 min at 0.3 W.kg-1, followed by 2.5 min of rest. One min spot views were taken with a gamma-radiation camera immediately after injection of 99mTc-antimony colloid and every 10 min thereafter to measure the clearance rate (CR) from the first and fourth finger-web of each hand. Radiopharmaceutical uptake in the axillary regions (AX) at 65 min postinjection was also measured. Clearance from the injection sites was linear and expressed as a slope (% administered activity.min-1). HI resulted in significantly greater CR (-0.24%.min-1+/-0.06) than LO (-0.19%.min-1+/-0.05; p=0.003). A similar trend was seen in AX (HI: 6.3%+/-1.6, LO: 4.8%+/-1.1, p=0.004).

CONCLUSIONS

The results indicate that an arm cranking protocol of higher intensity is more effective in promoting lymphatic clearance from the hand. Further, the high intensity protocol may be useful in the functional evaluation of the lymphatic system in breast cancer survivors and warrants further investigation.

Contrast-enhanced sonographic imaging of lymphatic channels and sentinel lymph nodes

OBJECTIVE

The purpose of this study was to determine whether lymphatic channels (LCs) and sentinel lymph nodes (SLNs) could be detected on sonographic imaging after subcutaneous, submucosal, or parenchymal injections of a sonographic contrast agent (ie, lymphosonography) in a variety of anatomic locations in several animal models.

METHODS

Eight swine, 7 canines, 4 rabbits, and a monkey were used for these evaluations. Gray scale pulse inversion harmonic imaging of the LCs and the SLNs was performed after subcutaneous (n = 58), submucosal (n = 14), or parenchymal (n = 8) injections of a tissue-specific sonographic contrast agent (Sonazoid; GE Healthcare, Oslo, Norway). In many instances, blue dye was injected into the same locations as Sonazoid, and surgical dissection of the SLNs and LCs was performed for comparison. Scanning electron microscopy (SEM) of contrast-enhanced and control lymph nodes from 2 rabbits was performed to determine the mechanism of contrast agent uptake and retention within SLNs.

RESULTS

After subcutaneous, submucosal, or parenchymal contrast agent injections, gray scale pulse inversion harmonic imaging could be used to identify the number and location(s) of LCs and SLNs. After subcutaneous, submucosal, or parenchymal contrast agent injections, Sonazoid was confined to the SLNs (ie, contrast enhancement was not detected in the second-echelon nodes). There was good agreement between the results of lymphosonography and blue dye with surgical dissection in identifying the regional LCs and SLNs. Scanning electron microscopy identified vacuoles representing intact contrast microbubbles within contrast-enhanced SLN macrophages, which were not present in the control lymph nodes.

CONCLUSIONS

Lymphosonography can be used to detect lymphatic drainage pathways and SLNs in a variety of animal models.

Sentinel lymph nodes in a swine model with melanoma: contrast-enhanced lymphatic US

PURPOSE

To determine if lymphatic channels and sentinel lymph nodes (SLNs) with and without metastases can be detected with lymphatic ultrasonography (US) after peritumoral injection of a US contrast agent and to determine if lymphatic US can be used to assess SLNs for the presence of metastatic infiltration.

MATERIALS AND METHODS

Six swine with 17 melanomas were evaluated. Conventional gray-scale, color flow, and gray-scale phase-inversion harmonic US examinations were performed. A US contrast agent was administered in four sites around each melanoma (1-mL total dose). Lymphoscintigraphy was followed by injection of a blue dye and then dissection. SLNs identified at lymphatic US were characterized by two readers in consensus as normal or as having metastases; results were compared with histologic findings. Statistical analyses included the sign test and the kappa statistic.

RESULTS

Lymphatic US depicted 28 SLNs, while lymphoscintigraphy depicted 27 "hot spots" suspected of representing SLNs (including two false-positive findings). Dissection after blue dye injection helped identify 31 SLNs. There were no false-positive US findings for SLN detection. Five of six nodes not seen with lymphoscintigraphy were detected with lymphatic US. The accuracy of SLN detection was 90% (28 of 31) for lymphatic US and 81% (25 of 31) for lymphoscintigraphy (P =.29). Lymphatic US correctly depicted metastases in 19 of 20 SLNs, and five of the eight normal SLNs were correctly characterized, with an accuracy of 86% (kappa = 0.62).

CONCLUSION

Detection of SLNs with lymphatic US compared favorably with that at lymphoscintigraphy. Lymphatic US can depict metastases within the SLN, which was not possible with lymphoscintigraphy.

Lymphoscintigraphy of melanoma: lymphatic channel activity guides localization of sentinel lymph nodes, and gamma camera imaging/counting confirms presence of radiotracer in excised nodes

Lymphoscintigraphy has become a standard preoperative procedure to map the cutaneous lymphatic channel for progression of nodal metastasis of melanoma of the skin. Lymphoscintigraphy was employed to visualize lymphatic channels as a guide to identify sentinel lymph nodes (SLNs). Excised tissue was imaged with a gamma camera to verify the findings of presurgical lymphoscintigraphy. Percent counts of SLN(s) among the total counts of the excised melanoma tumor or scar tissue and SLN(s) were calculated.

METHODS

Eleven patients with cutaneous melanoma received four to ten intradermal injections of Tc-99m sulfur colloid at elual distances around the melanoma site. Images were made immediately after injection: 1 minute per image for 15 min; and then 5 minutes or 1,000,000 counts per image for 30 min. After surgery, the excised melanoma tumor or scar and SLN(s) were imaged/counted with a gamma camera. Percent counts of SLNs among the total counts of the excised melanoma tumor or scar tissue and SLNs were calculated. To validate the specimen count accuracy, an experimental phantom study was done.

RESULTS

Linear lymphatic channels were identified between the injected sites and the SLNs in each patient. Gamma camera images demonstrated radioactivity in the SLNs of all patients, verifying the lymphoscintigraphy findings. Uptake in the SLNs of ten of the eleven patients ranged from 0.4 to 7.2% (mean 2.2%) of the total counts in excised tissue. We noted that a node with lower uptake should not be ignored because a lower percent of SLN activity does not necessarily rule out existing metastasis. In two of eleven patients, histopathologic showed metastases. One patient's melanoma on the middle back had lymphatic channel activity directed to both axillae. The results of the phantom study validated accuracy of our specimen counts.

CONCLUSIONS

Because linear lymphatic channels existed between lymph nodes and the injected sites in all eleven patients, these lymphatic channels could be used as a guide for localizing SLNs. The SLNs indicated by presurgical lymphoscintigraphy were verified by postoperative gamma camera imaging, and radiotracer localization in the SLNs averaged 2.2%.

Sentinel lymph node mapping in melanoma with technetium-99m dextran

PURPOSE

The aim of this work is to evaluate the capability of Tc99m B Dextran as a lymphoscintigraphic agent in the detection of the sentinel node in skin lesions.

MATERIALS AND METHODS

Forty-one patients with melanomas (39) and Merkel cell tumors (2) had perilesional intradermal injection of Tc99m-Dextran 2 hours before surgery. Serial gamma camera images and a handheld gamma probe were used to direct sentinel node biopsy.

RESULTS

In 39/41 patients, lymph channels and 52 sentinel nodes (one to three sentinel nodes/patient) could be visualized. In one patient, with a dorsal melanoma, no lymph channels or lymph nodes could be demonstrated on the images and only minimal radioactivity was found in the regional nodes with the probe. Another patient with a facial lesion failed to demonstrate lymph channels or nodes. No adverse reactions were observed.

CONCLUSION

Tc99m-Dextran provided good definition of lymph channels and sentinel node localization, without the risks related to the use of potentially hazardous labeled materials of biological origin.