The impact of dynamic lymphoscintigraphy and gamma probe guidance on sentinel node biopsy in melanoma

In cutaneous melanoma, biopsy of the first tumour-draining lymph node (sentinel node, SN) may replace routine elective lymph node dissection (ELND). Even in experienced hands the original technique using vital dyes fails to localise the SN in 20% of cases. In this study we investigated whether the procedure benefits from lymphoscintigraphy and the use of a gamma probe. In 41 patients technetium-99m-colloidal albumin was injected intracutaneously around the scar of the excised tumour. This was followed by dynamic and late static imaging. The first focal accumulation was assumed to be the SN. In all patients at least one SN was found, in 95% within the first 20 min. By showing multiple or ramifying lymphatic channels, dynamic lymphoscintigraphy differentiated between spill and multiple SNs. In all cases the initial focus retained the highest fraction of radioactivity for at least 18 h. The gamma probe was especially useful in the axilla and neck, where it accurately showed the optimal incision site and facilitated the search for deep-seated nodes. Gamma probe-localised SNs were dye-positive in 93% of cases. The SN contained metastases in 20% of the patients. Only in these patients was ELND performed, which revealed that the SN had been the only metastatic node in four of eight cases. We conclude that dynamic lymphoscintigraphy is essential for SN localisation, that tracer kinetics allow flexible timing of surgery, and that the surgical procedure benefits from use of the gamma probe

Impact of lymphoscintigraphy on sentinel node identification with technetium-99m-colloidal albumin in breast cancer

Identification of the sentinel node by using colloidal tracers and a gamma probe or lymphoscintigraphy could be an effective alternative for the complicated original dye-oriented approach. We studied the sentinel node detection rate using early and delayed imaging in breast cancer patients. Methods: Thirty-seven patients were imaged 2 hr and 18 hr after peritumoral injection of 99mTc-colloidal albumin. Preoperatively, axillary loci were located with a handheld gamma probe that was also used to isolate radiolabeled nodes from the axillary dissection specimens. The predictive value of the sentinel node for the axillary tumorstatus was evaluated with histological examination. Results: Two and 18 hr after injection, lymphoscintigraphy revealed one to three separate axillary lymph nodes in 33 and 34 patients, respectively. In 30 patients the axillary foci were easily localized with the gamma probe preoperatively. In all 34 patients (92%), with visualized axillary foci, at least one radioactive sample could be retrieved using the gamma probe (total 53 samples). Metastases were found in the sentinel nodes of 11 patients, in seven of 11 being the only tumor-positive lymph node in the axilla. There were no false-negative sentinel nodes. Conclusion: The selective targeting and prolonged intranodal retention of 99mTC-colloidal albumin allows successful sentinel node identification in most (92%) patients

Initial experience with a prototype dual-crystal (LSO/NaI) dual-head coincidence camera in oncology

The aim of this study was to evaluate the in vivo performance of a prototype dual-crystal [lutetium oxyorthosilicate (LSO)/sodium iodide (NaI)] dual-head coincidence camera (DHC) for PET and SPET (LSO-PS), in comparison to BGO-PET with fluorine-18 fluorodeoxyglucose (FDG) in oncology. This follows earlier reports that LSO-PS has noise-equivalent counting (NEC) rates comparable to partial ring BGO-PET, i.e. clearly higher than standard NaI DHCs. Twenty-four randomly selected oncological patients referred for whole-body FDG-PET underwent BGO-PET followed by LSO-PS. Four nuclear medicine physicians were randomised to read a single scan modality, in terms of lesion intensity, location and likelihood of malignancy. BGO-PET was considered the gold standard. Forty-eight lesions were classified as positive with BGO-PET, of which LSO-PS identified 73% (95% CI 60-86%). There was good observer agreement for both modalities in terms of intensity, location and interpretation. Lesions were missed by LSO-PS in 13 patients in the chest (n=6), neck (n=3) and abdomen (n=4). The diameter of these lesions was estimated to be 0.5-1 cm. Initial results justify further evaluation of LSO-PS in specific clinical situations, especially if a role as an instrument of triage for PET is foreseen

Diagnostic accuracy and interobserver variability of plain radiography, subtraction arthrography, nuclear arthrography, and bone scintigraphy in the assessment of aseptic femoral component loosening

Background: Plain radiography, subtraction arthrography, nuclear arthrography, and bone scintigraphy are imaging techniques commonly used to identify aseptic femoral component loosening. Controversy exists about the relative utility of these techniques. Patients and methods: W e evaluated the diagnostic accuracy and interobserver reliability of the four techniques in 78 consecutive patients (mean age 70 years, range 29-88 years) referred for evaluation of their femoral hip prostheses. The standard evaluation protocol consisted of plain radiography followed by subtraction arthrography, nuclear arthrography, and bone scintigraphy. Surgery or the subsequent clinical course of the patient was used as gold standard. Results: Over all, plain radiography had a sensitivity and specificity of 81 and 74%, respectively. Subtraction arthrography had a sensitivity of 47% and a specificity of 78%. Nuclear arthrography had a sensitivity of 69% and a specificity of 76%, and bone scintigraphy had a sensitivity of 88% with a specificity of 50%. Conclusion: We found considerable int erobserver variability in all four techniques. Multivariate regression analysis revealed that bone scintigraphy and nuclear arthrography together made a significant contribution to the diagnosis when used in combination with plain radiography and are, when plain radiography is inconclusive, useful additional diagnostic techniques for the detection of femoral component loosening

Sentinel Node and Recurrent Breast Cancer (SNARB): Results of a Nationwide Registration Study

Knowledge of regional lymph node involvement is important in patients with recurrent breast cancer for obtaining better locoregional control and predicting prognosis. To determine technical feasibility, validity, aberrant drainage rates, and clinical consequences of performing repeat sentinel node biopsy (SNB) in patients with locally recurrent breast cancer we conducted the "Sentinel Node and Recurrent Breast Cancer (SNARB)" study. A total of 150 patients with locally recurrent breast cancer underwent lymphatic mapping and SNB. In case of an intact axillary lymph node basin, ipsilateral axillary lymph node dissection (ALND) was performed subsequently. A total of 41 patients previously underwent breast conserving therapy (BCT) with SNB, 82 patients BCT with ALND, and 21 patients a mastectomy, of which 9 with SNB and 12 with ALND. In 95 patients (63.3 %) a sentinel node was identified and in 78 patients (52 %) the sentinel node was successfully removed. In 18 patients (22.8 %) a (micro)metastasis was found on pathologic examination. Confirmation ALND in 18 patients showed no axillary lymph node metastases. Aberrant drainage pathways were visualized in 58.9 % of the patients, significantly more frequently after a previous ALND (79.3 %) than after a previous SNB (25.0 %) (P <.0001). Overall, the result of this repeat SNB led to a change in the adjuvant treatment plan in 16.5 % of the patients with a successful repeat SNB. Repeat SNB is technically feasible and provides reliable results in patients with locally recurrent breast cancer, leading to change in management in 1 of 6 patients

Determinants of Diagnostic Performance Of [F-18]Fluorodeoxyglucose Positron Emission Tomography for Axillary Staging in Breast Cancer

OBJECTIVE: To prospectively investigate determinants of the accuracy of staging axillary lymph nodes in breast cancer using [F-18]fluorodeoxyglucose positron emission tomography (FDG PET). METHODS: Patients with primary operable breast cancer underwent FDG PET of the chest followed by sentinel node biopsy (SNB, n = 47) and/or complete axillary lymph node dissection (ALND, n = 23). PET scans were independently interpreted by three observers in a blinded fashion with respect to the FDG avidity of the primary tumor and the axillary status. The results were compared to histopathological analyses of the axillary lymph nodes. Clinicians were blinded to the PET results. RESULTS: Axillary lymph node specimens and FDG PET scans were evaluated in 70 patients (59% cT1). Overall, 32 (46%) had lymph node metastases as established by SNB (18/47) or ALND (14/23), 20 of which were confined to a single node. The overall sensitivity of FDG PET was 25%, with a specificity of 97%. PET results were false-negative in all 18 positive SNBs and true-positive in 8/14 in the ALND group. The performance of FDG PET depended on the axillary tumor load and the FDG avidity of the primary tumor. Intense uptake in the primary tumor was found in only 57% of the patients, and this was independent of the size. There was excellent interobserver agreement of visual assessment of FDG uptake in primary tumor and axillary lymph nodes. CONCLUSIONS: The sensitivity of FDG PET to detect occult axillary metastases in operable breast cancer was low, and it was a function of axillary tumor load and FDG avidity of the primary tumor. Even though the clinical relevance of occult disease detected by SNB needs to be confirmed, it is suggested that FDG PET in these patients should be focused on exploiting its nearly perfect specificity and the potential prognostic relevance of variable FDG uptake

A comparison of radiographic and scintigraphic techniques to assess aseptic loosening of the acetabular component in a total hip replacement

BACKGROUND: The diagnosis of a loose total hip prosthesis is often established with use of radiographic and nuclear medicine techniques, but there is controversy about the relative utility of plain radiography, subtraction arthrography, nuclear arthrography, and bone scintigraphy. In this retrospective study, we evaluated the sensitivity, specificity, and interobserver reliability of these imaging modalities in patients suspected of having aseptic loosening of the acetabular component. METHODS: From 1994 to 1999, eighty-six consecutive patients with pain after a total hip arthroplasty were evaluated for possible loosening of the components. The imaging evaluation included plain radiography followed by a one-day protocol that included bone scintigraphy, subtraction arthrography, and nuclear arthrography. For this study, two experienced nuclear medicine physicians and two experienced radiologists, all of whom were blinded with respect to the clinical pretest data and the clinical outcome, retrospectively interpreted the diagnostic images. The sensitivity and the specificity of each imaging modality were established by comparing the findings obtained with each technique with those found at surgery or during the subsequent clinical course of the patient. Interobserver variability was determined with the intraclass correlation coefficient. RESULTS: Plain radiography had a sensitivity of 85% (95% confidence interval, 71 to 94) and a specificity of 85% (95% confidence interval, 66 to 96) in detecting aseptic loosening of the acetabular component, but it had only fair interobserver variability (intraclass correlation coefficient, 0.37). For subtraction arthrography, the sensitivity was 72% (95% confidence interval, 57 to 84), the specificity was 70% (95% confidence interval, 50 to 86), and there was good interobserver variability (intraclass correlation coefficient, 0.71). For nuclear arthrography, the sensitivity was 57% (95% confidence interval, 41 to 71), the specificity was 67% (95% confidence interval, 46 to 84), and there was fair interobserver variability (intraclass correlation coefficient, 0.24). For bone scintigraphy, the sensitivity was 83% (95% confidence interval, 69 to 92), the specificity was 67% (95% confidence interval, 46 to 84), and there was moderate interobserver variability (intraclass correlation coefficient, 0.43). CONCLUSIONS: Plain radiography had the highest diagnostic accuracy in the evaluation of aseptic loosening of the acetabular component. The diagnostic accuracy was increased when plain radiography was combined with bone scintigraphy or subtraction arthrography. However, we found considerable interobserver variability in image interpretation, even with experienced radiologists and nuclear medicine physicians