Annals of Nuclear Medicine最新文献

Objective

Sentinel Lymph Node Biopsy (SLNB) is an important management tool for early-stage melanoma. Different radiopharmaceuticals are used internationally to localise the sentinel node using lymphoscintigraphy (LSG) before surgery. Recent reports have suggested that a delayed interval between LSG and SLNB using ^99mTc-labelled nanocolloid tracer has an adverse survival impact, but not with ^99mTc-labelled antimony sulphide colloid. This study aims to analyse survival outcome in a prospective cohort of melanoma patients undergoing same day or next day SLNB after LSG using ^99mTc-labelled nanocolloid.

Methods

Outcome data were reviewed for patients undergoing SLNB, stratified by time interval between LSG and SLNB at a single UK academic centre. Kaplan–Meier survival analysis was used to assess overall survival (OS), melanoma-specific survival (MSS) and progression-free survival (PFS). Cox multivariable regression analysis identified independent risk factors.

Results

925 patients had LSG using the ^99mTc-nanocolloid tracer between 2009 and 2019, with a median follow-up of 6.36 years. No difference was seen on univariate analysis in OS, MSS, PFS, or nodal recurrence between patients undergoing same day or next day SLNB (Log-rank P = 0.437, 0.293, 0.587, 0.342 respectively). In addition, nodal recurrence as first site or anytime site of recurrence in SLNB negative patients was similar between the groups (Log-rank P = 0.093 and 0.457 respectively). Stratified analysis of time did not demonstrate an outcome difference (MSS Log-rank P = 0.938). Cox multivariable regression did not show time interval to independently influence OS, MSS or PFS.

Conclusions

We do not find a significant effect on long-term outcomes when SLNB is performed the day after LSG with ^99mTc-labelled nanocolloid tracer. We infer that tracer migration is not clinically significant within 24 h of injection based on long term clinical outcome data.

Purpose

This study evaluated the usefulness of SUV analysis of 99mTc-galactosyl human serum albumin (99mTc-GSA) scintigraphy including SUV analysis of the cardiac blood pool normalized by blood volume as a predictor of short-term survival in severe liver failure.

Patients and methods

We enrolled 24 patients with severe liver failure who underwent 99mTc-GSA scintigraphy and were admitted to the intensive care unit. Patients were divided into survival and non-survival groups at 7, 14, and 28 days from the performance of 99mTc-GSA scintigraphy. From SPECT images we calculated SUVs of the cardiac blood pool, performing normalization for body weight, lean body weight, Japanese lean body weight, and blood volume and we calculated SUVs of the liver, normalizing by body weight, lean body weight, and Japanese lean body weight. We also calculated the uptake ratio of the heart at 15 min to that at 3 min (HH15) and the uptake ratio of the liver at 15 min to the liver plus the heart at 15 min (LHL15) from planar images of 99mTc-GSA scintigraphy.

Results

There were significant differences between the 7 day survival and non-survival groups for all SUVs of the heart and the liver and HH15, for 14 day survival groups in SUVs of the heart normalized by Japanese lean body weight and blood volume, and no significant differences between 28 day survival groups for any SUVs, HH15, or LHL15. Although the difference was not significant, SUV analysis of the heart normalized by blood volume showed the highest value for the area under the receiver-operating-characteristics curve for both 7 day and 14 day survival.

Conclusion

SUV analysis of 99mTc-GSA including SUV analysis of cardiac blood pool normalized by blood volume is of value for prediction of short-term survival in cases with severe liver failure.

Objective

Transient ischaemic dilatation (TID) had incremental diagnostic and prognostic value in obstructive coronary artery disease (CAD), but its clinical significance in patients with non-obstructive CAD remains unknown. We aimed to explore the prognostic value of TID in patients with non-obstructive CAD by ¹³N-ammonia PET imaging.

Methods

We retrospectively studied 131 consecutive patients with non-obstructive CAD undergoing one-day rest-stress ¹³N-ammonia PET myocardial perfusion imaging (MPI). TID was automatically generated using CardIQ Physio software. The receiver operative characteristic (ROC) curve was used to determine the optimal threshold of TID. The follow-up outcome was major adverse cardiac events (MACE), a composite of re-hospitalization for heart failure or unstable angina, late revascularization, non-fatal myocardial infarction, and cardiac death. Cardiac event-free survivals for normal and abnormal TID were compared using Kaplan–Meier plots and log-rank tests.

Results

During a median follow-up of 42.08 ± 17.67 months, 22 (16.7%) patients occurred MACE. The optimal cut-off value of TID was 1.03 based on MACE. Our preliminary outcome analysis suggests that TID-abnormal subjects had a lower overall survival probability. Furthermore, our multivariate analysis reveals abnormal TID was the only independent predictor for MACE in non-obstructive CAD. In the subgroup analysis, an abnormal TID was an independent predictor for MACE in patients with abnormal perfusion patterns.

Conclusion

Among patients with non-obstructive CAD, PET-derived TID ≥ 1.03 may identify those with a high risk of subsequent MACE independently. It was also an independent risk factor for poor prognosis in patients with abnormal perfusion.

Graphical abstract

CAD coronary artery disease, PET positron emission tomography, MPI myocardial perfusion imaging, TID transient ischaemic dilatation, MACE major adverse cardiac events, ROC receiver operative characteristic.

Objective: Amino acid positron emission tomography (PET) examinations using anti-1-amino-3-[¹⁸F]-fluorocyclobutane-1-carboxylic acid ([¹⁸F]FACBC) were allowed for routine clinical use in July 2024. However, phantom test procedures for [¹⁸F]FACBC reconstruction parameters have not yet been established. The present study aimed to establish new phantom test procedures for [¹⁸F]FACBC brain PET imaging to determine optimal reconstruction parameters.

Methods: Background (BG) activity as well as hot sphere and target-to-background ratios (TBRs) of [¹⁸F]FACBC were estimated based on brain activity and tumor-to-normal tissue ratios (TNR) in a Japanese clinical trial of [¹⁸F]FACBC. Phantom experiments proceeded under [¹⁸F]FACBC or L-[methyl-¹¹C]-methionine ([¹¹C]MET) conditions. The number of iterations and the Gaussian filter parameters were determined from the reconstruction parameters %contrast_mean and coefficients of variation (CVs) in ordered subset expectation maximization (OSEM) and time-of-flight (TOF) with or without point-spread-function (PSF) correction.

Results: The amounts of activity in the hot spheres and BG were 1.1 and 5.5 kBq/mL, respectively, and the TBR was 5.0 at the start of acquisition. The %contrast_mean of all hot spheres was higher with [¹⁸F]FACBC than [¹¹C]MET, and %contrast_mean converged between 4 and 6 iterations in hot spheres with diameters < 10 mm. We used four iterations for OSEM + TOF and five for OSEM + TOF + PSF correction for [¹⁸F]FACBC and [¹¹C]MET images. The CV was higher for [¹⁸F]FACBC than [¹¹C]MET. The optimal sizes of Gaussian filters for OSEM + TOF and OSEM + TOF + PSF correction of image reconstruction were 5 mm for [¹⁸F]FACBC, and 4 and 3 mm, respectively, for [¹¹C]MET images.

Conclusions: We estimated phantom activity and TBR based on brain activity in a Japanese clinical trial and established new phantom test procedures for [¹⁸F]FACBC. We recommend that the optimal reconstruction parameters for [¹⁸F]FACBC should be set to the same number of iterations as [¹¹C]MET and that the FWHM of Gaussian filter should have a few mm higher than [¹¹C]MET to reduce image noise from brain normal tissue.

Purpose: In this study, we aimed to evaluate the response of the primary and metastatic liver tumors to radioembolization with ⁹⁰Y glass microspheres and investigate its correlations with dosimetric variables calculated with ⁹⁰Y PET/MRI.

Methods: In this ambispective study, 44 patients treated with ⁹⁰Y glass microspheres and imaged with ⁹⁰Y PET/MRI were included for analysis. Dosimetric analysis was performed for every perfused lesion using dose-volume histograms. Response was assessed by comparing pre-treatment and follow-up total lesion glycolysis (TLG) values derived from ¹⁸F-FDG PET imaging. The relationship between ΔTLG and log-transformed dosimetric variables was analyzed with linear mixed effects regression models. ROC analyses were performed to compare discriminatory power of the variables in predicting response and complete response.

Results: Regression and ROC analyses demonstrated that mean tumor dose and almost all D values were statistically significant predictors of treatment response and complete treatment response. Specifically, D60, D70 and D80 values exhibited significantly higher discriminatory power for predicting treatment response compared to the mean dose (D_mean) delivered to tumor. High specificity cut-off values to predict response were determined as 160.75 Gy for D_mean, 95.50 Gy for D60, 89 Gy for D70, and 59.50 Gy for D80. Similarly, high-specificity cut-off values to predict complete response were 262.75 Gy for D_mean, 173 Gy for D70, 140.5 Gy for D80, and 100 Gy for D90.

Conclusion: In this study, we demonstrated that voxel-based dosimetry with post-treatment ⁹⁰Y PET/MRI can predict response to treatment. D60, D70 and D80 variables also did have greater discriminatory power compared to D_mean in prediction of response. In addition, we present high-specificity cut-offs to predict response (CR + PR) and complete response (CR) for both D_mean and several D variables derived from dose-volume histograms.