Dataset Information

Microsurgery guided by sequential preoperative lymphography using 68Ga-NEB PET and MRI in patients with lower-limb lymphedema.

ABSTRACT: OBJECTIVE:The popularity of contemporary microsurgical techniques in treatment of lower-limb lymphedema calls for better visualization of the lymphatic system, both preoperatively and intra-operatively. The aim of this prospective study was to investigate the feasibility of a novel combination of 68Ga-NEB positron emission tomography (PET) with magnetic resonance lymphography (MRL) in evaluating lymphedema and guiding surgical intervention. METHODS:A total of 11 patients (F 9, M 2, age range 29-69 y) with lower-limb lymphedema classified into stage I to III were recruited. PET acquisition was performed at 30, 60 and 90 min after subcutaneous injection of the albumin-binding radiotracer 68Ga-NEB into the bilateral first web spaces of the feet. All the patients were also subjected to 99mTc-sulfur colloid (SC) lymphoscintigraphy for comparison. Gd-DTPA-enhanced magnetic resonance imaging (MRI) was performed using sequences specialized for lymphatic vessel scans. All the patients underwent surgical interventions within a week. The surgical approach includes the use of a linear marker for edema localization and indocyanine green (ICG) lymphography with a near-infrared surgical navigation system intra-operatively. RESULTS:Lymph transport in lymphatic channels was clearly observed by visualization of 68Ga-NEB activity in the lymphatic vessels and within lymph nodes for all 11 patients as well as the visualization of the edema section plane with dermal backflow (DB), abnormally increased and disconnected uptake along the lymphatic channels. Preoperative 68Ga-NEB PET combined with MRL provides advantageous three-dimensional images, higher temporal resolution, significantly shorter time lapse before image acquisition after tracer injection and more accurate pathological lymphatic vessel distribution than 99mTc-SC lymphoscintigraphy combined with MRI. CONCLUSION:This study documented an effective imaging pattern to combine 68Ga-NEB PET and MRL in patients with lower-limb lymphedema. This strategy demonstrated significant advantage over 99mTc-SC lymphoscintigraphy/MRL in the evaluation of lymphedema severity, staging and pathological location of lymph vessels to make an individualized treatment plan. Dual 68Ga-NEB PET/MRL is thus recommended before the operation for staging and therapy planning.

SUBMITTER: Long X

PROVIDER: S-EPMC5507721 | biostudies-literature | 2017 Aug

REPOSITORIES: biostudies-literature

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Microsurgery guided by sequential preoperative lymphography using <sup>68</sup>Ga-NEB PET and MRI in patients with lower-limb lymphedema.

Long Xiao X Zhang Jingjing J Zhang Daming D Gao Chao C Chi Chongwei C Yang Elan E Xue Huadan H Lang Lixin L Niu Gang G Zhu Zhaohui Z Li Fang F Chen Xiaoyuan X

European journal of nuclear medicine and molecular imaging 20170405 9

<h4>Objective</h4>The popularity of contemporary microsurgical techniques in treatment of lower-limb lymphedema calls for better visualization of the lymphatic system, both preoperatively and intra-operatively. The aim of this prospective study was to investigate the feasibility of a novel combination of <sup>68</sup>Ga-NEB positron emission tomography (PET) with magnetic resonance lymphography (MRL) in evaluating lymphedema and guiding surgical intervention.<h4>Methods</h4>A total of 11 patient ...[more]

PMID: 28382512

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Project description:UNLABELLED:Suitably labeled Evans blue dye has been successfully applied to evaluate cardiac function, vascular permeability, and lymphatic imaging in preclinical settings. This study documented the first-in-human application of 68Ga-1,4,7-triazacyclononane-N,N',N?-triacetic acid (NOTA)-NEB. METHODS:The NOTA-conjugated truncated form of Evans blue, NEB, was labeled with 68Ga and tested in BALB/C mice for dynamic PET and ex vivo biodistribution studies. Three healthy volunteers (2 men and 1 woman) underwent 90-min whole-body dynamic PET. The absorbed doses for major organs and whole body were calculated using OLINDA/EXM software. Eleven patients with focal hepatic lesions diagnosed by enhanced CT or MR imaging were subjected to whole-body PET/CT acquisitions at 30 min after intravenous injection of 111-148 MBq (3-4 mCi) of 68Ga-NEB. RESULTS:NEB dye was labeled with 68Ga (half-time, 68 min) with high yield and purity. After intravenous injection, 68Ga-NEB formed a complex with serum albumin, thus most of the radioactivity was retained in blood circulation. The tracer was demonstrated to be safe in both healthy volunteers and recruited patients without side effects or allergies. Among the 11 patients, hemangiomas showed much higher 68Ga-NEB signal intensity than the surrounding normal hepatic tissues, whereas no apparent difference between lesions and hepatic tissues was identified on 18F-FDG PET. All other focal hepatic lesions including hepatocellular carcinoma, hepatic cysts, and neuroendocrine tumor liver metastases showed negative 68Ga-NEB contrast to hepatic tissues. CONCLUSION:As a blood-pool imaging agent, 68Ga-NEB is safe to use in the clinic, and our preliminary studies demonstrate the value of differentiating hepatic hemangioma from other benign or malignant focal hepatic lesions. Easy labeling with different positron emitters of various half-lives, excellent pharmacokinetics, and imaging quality warrant further clinical applications of NEB-based PET tracers.

Project description:BACKGROUND:Prosthetic joint infections may lead to failures of total joint arthroplasty. Radionuclide imaging can play a diagnostic role in identifying such infections, which require two-stage exchange arthroplasty (instead of simple revision surgery performed in non-infected cases). Although 18F-FDG PET/CT has emerged as a novel diagnostic tool in this setting, the clinical usefulness of 68Ga-citrate PET/CT has not been previously investigated. This single-center prospective study was designed to address this issue. METHODS:Between January 2016 and October 2017, we examined 34 patients with clinically proven or suspected prosthetic hip/knee joint infections scheduled to undergo surgery. All patients underwent 68Ga-citrate PET/CT scans and sequential 18F-FDG PET/CT imaging for comparative purposes. Intraoperative findings and the results of microbiological analyses of surgical specimens served as gold standard. The diagnostic results were examined according to (1) image interpretation based on radiotracer uptake patterns and (2) quantitative analysis using volumes of interest (VOIs) to calculate standard uptake values (SUVs) and metabolic volumes (MVs). RESULTS:A total of 26 (76%) patients were diagnosed as having infections. Based on radiotracer uptake pattern criteria, the sensitivity, specificity, and accuracy of 68Ga-citrate PET/CT and 18F-FDG PET/CT were 92%, 88%, and 91% and 100%, 38%, and 85%, respectively. MV was significantly higher in the infected group when 68Ga-citrate PET/CT was used (422.45 vs. 303.65 cm3, p?=?0.027), whereas no significant differences were observed on 18F-FDG PET/CT. According to receiver operating characteristic (ROC) curve analysis, a cut-off value of 370.86 for MV resulted in a sensitivity of 61.5% and a specificity of 87.5% (area under curve: 0.75, 95% confidence interval: 0.57-0.88, p?=?0.035). CONCLUSIONS:Subject to future confirmation, our data provide preliminary evidence that 68Ga-citrate PET/CT may have a complimentary role to 18F-FDG PET/CT in detecting prosthetic joint infections, being characterized by a higher specificity and the possibility to discriminate between an infectious condition and sterile inflammation. TRIAL REGISTRATION:This prospective study was registered at clinicaltrials.gov (registration number: NCT02855190 ).

Project description:In contrast to ordered subset expectation maximization (OSEM), block sequential regularized expectation maximization (BSREM) positron emission tomography (PET) reconstruction algorithms can run until full convergence while controlling image quality and noise. Recent studies with BSREM and 18F-FDG PET reported higher signal-to-noise ratios and higher standardized uptake values (SUV). In this study, we investigate the optimal regularization parameter (?) for clinical 68Ga-PSMA PET/MR reconstructions in the pelvic region applying time-of-flight (TOF) BSREM in comparison to TOF OSEM. Two-minute emission data from the pelvic region of 25 patients who underwent 68Ga-PSMA PET/MR were retrospectively reconstructed. Reference OSEM reconstructions had 28 subsets and 2 iterations. BSREM reconstructions were performed with 15 ? values between 150 and 1200. Regions of interest (ROIs) were drawn around lesions and in uniform background. Background SUVmean (average) and SUVstd (standard deviation), and lesion SUVmax (average of 5 hottest voxels) were calculated. Differences were analyzed using the Wilcoxon matched pairs signed-rank test.A total of 40 lesions were identified in the pelvic region. Background noise (SUVstd) and lesions SUVmax decreased with increasing ?. Image reconstructions with ? values lower than 400 have higher (p?<?0.01) background noise, compared to the reference OSEM reconstructions, and are therefore less useful. Lesions with low activity on images reconstructed with ? values higher than 600 have a lower (p?<?0.05) SUVmax compared to the reference. These reconstructions are likely visually appealing due to the lower background noise, but the lower SUVmax could possibly render small low-uptake lesions invisible.In our study, we showed that PET images reconstructed with TOF BSREM in combination with the 68Ga-PSMA tracer result in lower background noise and higher SUVmax values in lesions compared to TOF OSEM. Our study indicates that a ? value between 400 and 550 might be the optimal compromise between high SUVmax and low background noise.

Dataset Information

Microsurgery guided by sequential preoperative lymphography using 68Ga-NEB PET and MRI in patients with lower-limb lymphedema.

Publications

Microsurgery guided by sequential preoperative lymphography using <sup>68</sup>Ga-NEB PET and MRI in patients with lower-limb lymphedema.

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