Computed tomographic lymphography for sentinel lymph node biopsy in male breast cancer: report of two cases

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.

Long-term observation of indirect lymphography using gadolinium-loaded polyethylenimine-entrapped gold nanoparticles as a dual mode CT/MR contrast agent for rabbit lingual sentinel lymph node identification

CONCLUSIONS

The rabbit lingual sentinel lymph node (SLN) could be long-term visualized by indirect lymphography using gadolinium-loaded polyethylenimine-entrapped gold nanoparticles (Gd-Au PENPs) as CT/MR dual-modal contrast agent.

OBJECTIVE

To investigate duration and intensity of rabbit lingual SLN enhancement using Gd-Au PENPs as a CT/MR dual-modal contrast agent.

METHODS

Twelve rabbits were randomly divided into indirect CT lymphography (CT-LG) and MR lymphography (MR-LG) groups. In each group, two rabbits received unilateral injection and four received bilateral injection of Gd-Au PENPs in the sub-mucosa of the tongue. Then the enhancement characteristics of SLN were investigated.

RESULTS

The enhanced SLNs were observed in 100% in all rabbits by indirect CT-LG and MR-LG simultaneously at 1 min after injection. Then SLN enhancement was improved rapidly and the first peaks were observed at 25 min for CT-LG and 1 h for MR-LG, respectively, then SLN enhancement decreased gradually to a minimum at 2 h for CT-LG and 3 h for MR-LG. Afterwards, the enhancement intensity increased again and second peaks were observed at 24 h for both CT-LG and MR-LG. Hereafter, the intensity dropped slowly and weak enhancement was also observed at the 40th week for CT-LG and 31st day for MR-LG. Black-stained SLNs were visualized in 100% at autopsy in all rabbits.

Short-Term Dynamic Observation of the Color Change and Enhancement Effect of Polyethylenimine-Entrapped Gold Nanoparticles Used for Indirect Lymphography

AIMS

To dynamically observe the color change and enhancement effect of gadolinium-loaded polyethylenimine-entrapped gold nanoparticles (Gd-Au PENPs) as a dual-mode CT/MRI contrast agent for sentinel lymph node (SLN) identification.

METHODS

In 6 rabbits, Gd-Au PENPs were injected into the right side tongue submucosa, after which the color change of cervical draining lymph nodes was observed. Then the draining lymph nodes were examined by CT/MRI scan. Another 6 rabbits were randomly divided into a CT lymphography (CT-LG) and a MRI lymphography (MRI-LG) group and examined by CT/MRI scan 1 and 30 min after injection. Then SLNs were identified under the guidance of CT/MRI-LG.

RESULTS

The ipsilateral afferent lymphatic vessels, cervical draining lymph nodes and efferent lymphatic vessels were stained black orderly and constantly after Gd-Au PENPs injection. Thirty minutes after injection, all cervical lymph nodes were excised to be examined by CT/MRI scan, and only the black-stained draining lymph nodes were enhanced. The 6 rabbits with CT/MRI-LG showed clear enhancement of SLNs. With indirect lymphography, the black-stained SLNs were easily visualized at autopsy. In all rabbits, the identification rate of lingual SLNs was 100%.

CONCLUSIONS

Rabbit lingual SLNs could be identified with indirect lymphography using Gd-Au PENPs as a dual-mode contrast agent.