Sentinel node imaging in breast cancer using superficial injections: Technical details and observations

Introduction

Sentinel lymph node (SLN) biopsy is the evolving standard of care for the management of early breast cancer. Accurate identification of the SLN is paramount for success of this procedure. Various techniques are described for SLN identification, but the superficial injection techniques, advocated by the UK National Training Programme (NEW START), are validated, reproducible and rapid. Pre-operative lymphoscintigraphy provides a road map for the surgeon and requires a reporting template.

Methods

As one of the NEW START training institutions in the UK practising this technique, we reviewed a mature series of 100 unselected, consecutive SLN lymphoscintigraphy procedures. We correlated the imaging, operative and pathology findings and have provided technical details of the technique and a template for reporting SLN lymphoscintigrams.

Results

The SLN localisation rate was 99% with one failed imaging. Seven patients required delayed imaging. The mean activity of the radiocolloid injected was 14.4 MBq (range 8.3–23 MBq). The SLNs were visualised in the ipsilateral axilla in 98 images, intramammary in 3, and internal mammary in 1. A mean of 1.35 nodes were classified as ‘True’ SLNs on imaging criteria. Intra-operatively, a mean of 1.91 SLNs were excised. 32 of 116 hot and blue nodes, 7 of 15 only blue nodes, 13 of 47 only hot and 7 of 13 parasentinel nodes harboured metastases.

Conclusion

The NEW START recommended, combined superficial injection techniques, have high localisation rates. Pre-operative sentinel node imaging is recommended and a template for reporting is provided.     

综合影像学诊断下肢乳糜反流性淋巴水肿

目的 探讨下肢乳糜反流性淋巴水肿的影像学表现.方法 回顾性分析26例患者27侧下肢肢体乳糜反流性淋巴水肿的影像学资料.所有患者均接受直接淋巴管造影(DLG)、造影后CT、核素淋巴显像检查,其中4例接受盆腔MR扫描,11例接受下肢MR扫描.结果 DLG示26例患者可见下肢乳糜反流,26例胸导管出口不同程度受阻;造影后CT所见与其基本吻合.核素淋巴显像显示27侧下肢肢体淋巴肿,伴9例阴囊淋巴水肿,19例胸导管出口梗阻;21例接受单侧淋巴显像,均证实乳糜反流存在.MRI示下肢、盆壁水肿呈网格状长T2信号.结论 DLG及核素淋巴显像可直接、动态显示淋巴系统异常;DLG后CT可弥补二者空间分辨力较低的缺陷,并可清晰显示周围组织的情况.MRI可以明确肢体淋巴水肿的部位及范围,鉴别水肿的类型.     

Lymphatic obstruction in Rheumatoid arthritis

Summary We describe four patients with rheumatoid arthritis and unilateral upper limb oedema. In all cases, qualitative lymphoscintigraphy showed lymphatic obstruction in the affected limb.     

Iliopelvic lymphoscintigraphy with99mTc-dextran in malignant lymphoma

^99mTc-Dextran (^99mTc-D) was evaluated as an iliopelvic lymphoscintigraphic agent in 49 patients with malignant lymphoma and the results were compared with ultrasound (US), lymphangiography (LA) and CT where available. Scintigrams were obtained by a gamma camera at 2 h postinjection and evaluated by comparing opposite sides. In 29 of 49 patients, normal lymphoscintigrams of excellent quality, deliniating the iliopelvic and paraaortic lymph nodes bilaterally were obtained. In 20 patients lymphoscintigraphy (LS) was positive. US was performed in 46 patients, 20 had positive and 26 negative findings. There was one false positive and one false negative in LS compared to US. Ten patients had LA and 3 had CT. These results were in complete agreement with LS. There was also a positive correlation between the clinical stages and the results of LS. This study showed that^99mTc-D is an excellent radiopharmaceutical for the visualization of the lymph system with high correlation with other imaging modalities.     

Clinical evaluation of lymphoscintigraphy of the head and neck

Thirty-six patients underwent static and dynamic lymphoscintigraphies with 99m-Tc rhenium colloid in this series. Static lymphoscintigrams were obtained at 3 hours after injection and dynamic lymphoscintigraphy was carried out immediately after injection. 99m-Tc rhenium colloid in each volume of 0.25ml (3.7×10⁷ Bq) was applied by subcutaneous injection into bilateral areas behind the ears for the cervical lymph nodes, and by submucosal injection into the bilateral mucobuccal folds of the upper molar region for the submandibular lymph nodes. Most of the cases demonstrated abnormalities of the lymph node images; (1) asymmetry of lymph node drainage, (2) absence of lymph nodes, (3) reduced uptake, (4) rope-like appearance, (5) enlargement of lymph nodes, and (6) delay of flow rate along the cervical chain. The results of these two imaging techniques correctly predicted the metastatic involvement of cervical lymph nodes from malignant tumors at the rate of about 70%. This imaging technique of lymphoscintigraphy is one of the useful method for evaluating lymph node metastasis, and dynamic scintigraphy especially contributes to more accurate diagnosis of lymph node metastasis.     

Kinetics and dosimetry of iodine-131-labelled antibody fragments after local administration in patients with rectal cancer

In 11 patients with rectal cancer, a mixture of F(ab)₂ fragments of anti-carcinoembryonic antigen and anti-CA 19.9 labelled with a diagnostic dose of iodine-131 (3–10 MBq) was administered submucosally around the tumour. In this study, the local kinetics in and the dose to the rectal wall, the whole body kinetics and the effective dose equivalent are presented. The early disappearance of the activity from the injection spot was characterized by a T _1/2 of 21 h. Initially, about 50% of the plasma activity was due to free ¹³¹I. After 4 h, the plasma activity was almost completely protein bound (86%). Maximum plasma activity was observed after the 2nd day. From 72 h p.i., the plasma activity decreased with a T _1/2 of 53 h. In the first 24 h, 14% of the injected dose was excreted in the urine and within 4 days about half of the administered activity. The absorbed radiation dose to the rectal wall was estimated to be 0.2 Gy/MBq, presuming a 20 cm³ distribution volume. The dose to the bone marrow was 0.2 mGy/MBq or 0.4 mGy/MBq, assuming a homogeneous tracer distribution or equal blood and bone marrow activity concentrations, respectively. The effective dose equivalent is 1.9 mSv/MBq, mainly determined by the dose to the rectal wall and to a lesser extent by the dose to the remaining body. Postulating comparable kinetics, ¹²³I- or ¹¹¹In- or ^99mTc-labelled fragments would result in 4-25-fold lower effective dose equivalents. We conclude that the theoretical advantages of the local administration of ¹³¹I-labelled antibodies for diagnostic purposes in patients with rectal cancer are not limited by our dosimetric data. Nevertheless, we advocate the use of other radiolabels with more appropriate imaging qualities and probably a lower radiation burden. Offprint requests to: E.J. Derksen     

Hybrid SPECT-CT: an additional technique for sentinel node detection of patients with invasive bladder cancer

OBJECTIVES: To explore the feasibility of performing lymphoscintigraphy combined with computed tomography (CT) for preoperative detection of sentinel lymph nodes in patients with invasive bladder cancer. MATERIALS: Six consecutive patients scheduled for radical cystectomy underwent lymphoscintigraphy after transurethral injection of Albures-technetium 99m in the detrusor muscle peritumourally both with planar imaging and with single-photon emission computed tomography/CT (SPECT/CT). CT for anatomic fusion was performed directly after the SPECT/CT and both investigations were combined to a fused image. Radical cystectomy started with extended lymphadenectomy and intraoperative detection of sentinel nodes with both Geiger probe and dye marker. The conventional planar lymphoscintigraphies and the fused SPECT/CT were compared with each other and with the outcome of intraoperative sentinel node detection and final histopathologic analyses. RESULTS: The method allowed anatomically detailed preoperative visualisation of 21 sentinel nodes in five of the six patients, whereas planar pictures only visualised two sentinel nodes in two of six patients. Two patients had lymph node metastases and in the other four the nodes were negative. The combined method visualised all metastatic sentinel nodes, whereas planar lymphoscintigraphy detected only one of six node metastases. CONCLUSIONS: The combination of lymphoscintigraphy with CT enhanced preoperative anatomic localisation of sentinel nodes in bladder cancer and aided in the identification of sentinel nodes during surgery. The yield of detected sentinel nodes, both metastatic and nonmetastatic, was markedly increased using the combined method compared to conventional planar lymphoscintigraphy.