Precise localisation of a sentinel lymph node in a rare drainage region with SPECT/MRI using interstitial injection of 99mTc-nanocolloid and superparamagnetic iron oxide

Sentinel lymph node biopsy using dynamic lymphoscintigraphy combined with ultrasound-guided fine needle aspiration in penile carcinoma

The purpose of this study was to assess the utility of sentinel lymph node lymphoscintigraphy (SLNL) and ultrasound-guided fine needle aspiration cytology (FNAC) in patients with penile carcinoma. A prospective study was undertaken of 64 patients with stage T1 (or greater) clinically N0 squamous cell carcinoma of the penis. Patients underwent SLNL and bilateral groin ultrasonography with or without FNAC. Following intradermal blue dye, patients underwent unilateral or bilateral sentinel lymph node excision biopsy (SNB). 17 patients had sentinel nodes that contained metastases (21 nodal basins). Lymphatic drainage was demonstrated in all patients by lymphoscintigraphy. Bilateral drainage was seen in 57/64 patients. 61/64 patients had ultrasonography of the inguinal basins on the same day as FNAC of 38 basins. FNAC showed malignancy in eight basins. FNAC was negative in six basins, which were subsequently shown to be positive following SNB. 82 inguinal basins did not warrant FNAC by ultrasound criteria, of which 5 contained metastases at SNB. The sensitivity and specificity of ultrasonography was 74% and 77%, respectively. The positive and negative predictive values were 37% and 94%, respectively. Two patients had a negative initial SNB; however, ultrasonography identified a metastatic node and re-evaluation of the sentinel node confirmed micro-metastases. There has been no evidence of recurrence in any patients with negative SNB (during 6-28 months' follow-up). In conclusion, when investigating clinically stage N0 penile cancer, the combination of SNB and groin ultrasonography, with or without FNAC, identifies accurately those with occult nodal metastases. Ultrasonography alone is not adequate as a staging technique, and SNB alone might miss between 5% and 10% of metastases.

Lanthanide-loaded liposomes for multimodality imaging and therapy

Many advanced molecular imaging agents are currently being investigated preclinically. Especially, liposomes, have proven to be very promising carrier systems for diagnostic agents for use in single-photon emission computed tomography (SPECT) or magnetic resonance imaging (MRI), as well as for therapeutic agents to treat diseases such as cancer. In this study, nanosized liposomes were designed and labeled with the radionuclides, holmium-166 (both a beta- and gamma-emitter and also highly paramagnetic) or technetium-99m, and coloaded with paramagnetic gadolinium allowing multimodality SPECT and MR imaging and radionuclide therapy with one single agent.

METHODS

Diethylenetriaminepentaacetic acid bisoctadecylamide (an amphiphilic molecule with a chelating group suitable for labeling with radionuclides) and gadoliniumacetylacetonate (GdAcAc) (a small lipophilic paramagnetic molecule) were incorporated in liposomes. The liposomes were characterized by measuring their mean size and size distribution, gadolinium content, and radiochemical stability after incubation in human serum at 37 degrees C. The MRI properties (in vitro) were determined by use of relaxivity measurements at 1.5 and 3.0 Tesla in order to evaluate their potency as imaging agents.

RESULTS

The liposomes were successfully labeled with holmium-166, resulting in a high labeling efficiency (95% +/- 1%) and radiochemical stability (> 98% after 48 hours of incubation), and coloaded with GdAcAc. Labeling of liposomes with technetium-99m was somewhat less efficient (85% +/- 2%), although their radiochemical stability was sufficient (95% +/- 1% after 6 hours of incubation). MRI measurements showed that the incorporation of GdAcAc had a strong effect on the MRI relaxivity.

CONCLUSIONS

The synthesized liposomes allow for multimodality imaging and therapy, which makes these new agents highly attractive for future applications.

Multimodal fusion imaging ensemble for targeted sentinel lymph node management: initial results of an innovative promising approach for anatomically difficult lymphatic drainage in different tumour entities

PURPOSE

There are situations where exact identification and localisation of sentinel lymph nodes (SLNs) are very difficult using lymphoscintigraphy, a hand-held gamma probe and vital dye, either a priori or a posteriori. We developed a new method using a simultaneous injection of two lymphotropic agents for exact topographical tomographic localisation and biopsy of draining SLNs. The purpose of this prospective pilot study was to investigate the feasibility and efficacy of this method ensemble.

METHODS

Fourteen patients with different tumour entities were enrolled. A mixture of (99m)Tc-nanocolloid and a dissolved superparamagnetic iron oxide was injected interstitially. Dynamic, sequential static lymphoscintigraphy and SPECT served as pathfinders. MR imaging was performed 2 h after injection. SPECT, contrast MRI and, if necessary, CT scan data sets were fused and evaluated with special regard to the topographical location of SLNs. The day after injection, nine patients underwent SLN biopsy and, in the presence of SLN metastasis, an elective lymph node dissection.

RESULTS

Twenty-five SLNs were localised in the 14 patients examined. A 100% fusion correlation was achieved in all patients. The anatomical sites of SLNs detected during surgery showed 100% agreement with those localised on the multimodal fusion images. SLNs could be excised in 11/14 patients, six of whom had nodal metastasis.

CONCLUSION

Our novel approach of multimodal fusion imaging for targeted SLN management in primary tumours with lymphatic drainage to anatomically difficult regions enables SLN biopsy even in patients with lymphatic drainage to obscure regions. Currently, we are testing its validity in larger patient groups and other tumour entities.

The Role of Lymphoscintigraphy in the Detection of Lymph Node Drainage in Melanoma

Lymphatic drainage of the skin cannot be predicted based on clinical guidelines developed more than 100 years ago. Approximately 30% of patients experience drainage from the skin to unexpected lymph node sites rather than those specified by these guidelines, and therefore these outdated assumptions should no longer be used to plan surgery. A possible survival benefit has been shown for the early detection and surgical removal of metastatic disease in the draining lymph nodes, and therefore, clinicians must obtain accurate lymphatic mapping for each patient who has intermediate thickness melanoma to plan appropriate surgical therapy. Lymphoscintigraphy can be used to accurately define the precise position of each true sentinel node in every patient, whether these nodes lie in a standard node field or in an unusual location. In this way, lymphoscintigraphy has a direct beneficial impact on the surgical management of patients who have melanoma.