This study was done to determine the diagnostic value of whole-body magnetic resonance using diffusion-weighted imaging with background suppression (WB-DWIBS) for detecting bone metastases compared with whole-body bone scintigraphy (WB-BS).

AIMThe aim of the study was to assess the reproducibility (R) and variability of quantitative parameters derived from Cedars-Sinai QGS software for phase analysis of G-SPECT in 39 coronary artery disease (CAD) patients with or without severe heart-failure (HF).METHODSPhase standard deviation (s) and entropy (e) are global parameters that quantify dyssynchrony. Regional measures of dyssynchrony were also computed including differences between the lateral wall versus the septal wall (DmW) and differences between the averages of midventricular lateral versus midventricular septal segments (DmS).RESULTSGlobal parameters e and s and regional parameters DmW and DmS exhibit excellent values of R=0.92, 0.99, 0.99 and 0.96, respectively. In regional parameters DmW and DmS there is a significant variability in individual scoring assessed by a standard error of measurement of =9.17 and 21.7, respectively. The box plots of e in patients with or without HF do not show any significant superimposition, while the box plots of s and DmW show a partial overlap mainly due to the significant variability of s and DmW within patients with HF. Conversely the box plots of DmS in patients with or without HF show a significant overlap due to the great variability of DmS within patients with HF.CONCLUSIONRegional parameters derived from phase analysis of G-SPECT studies are not useful in the individual assessment of dyssynchrony in CAD patients either due to large variability in individual scoring and to a large heterogeneity in HF patients. Global parameters (e and s) exhibit both an excellent reproducibility. Nonetheless, e seems to perform better than s in individual assessment of dyssynchrony due to a better separation between HF and non HF patients. Using the QGS software approach no manual intervention is necessary to ensure a good reproducibility of global parameters.

The purpose of this study was to quantify the influence of outside field of view (FOV) activity concentration (Ac,out) on the noise equivalent count rate (NECR), scatter fraction (SF) and image quality of a 3D LSO whole-body PET/CT scanner. The contrast-to-noise ratio (CNR) was the figure of merit used to characterize the image quality of PET scans. A modified International Electrotechnical Commission (IEC) phantom was used to obtain SF and counting rates similar to those found in average patients. A scatter phantom was positioned at the end of the modified IEC phantom to simulate an activity that extends beyond the scanner. The modified IEC phantom was filled with 18F (11 kBq mL−1) and the spherical targets, with internal diameter (ID) ranging from 10 to 37 mm, had a target-to-background ratio of 10. PET images were acquired with background activity concentrations into the FOV (Ac,bkg) about 11, 9.2, 6.6, 5.2 and 3.5 kBq mL−1. The emission scan duration (ESD) was set to 1, 2, 3 and 4 min. The tube inside the scatter phantom was filled with activities to provide Ac,out in the whole scatter phantom of zero, half, unity, twofold and fourfold the one of the modified IEC phantom. Plots of CNR versus the various parameters are provided. Multiple linear regression was employed to study the effects of Ac,out on CNR, adjusted for the presence of variables (sphere ID, Ac,bkg and ESD) related to CNR. The presence of outside FOV activity at the same concentration as the one inside the FOV reduces peak NECR of 30%. The increase in SF is marginal (1.2%). CNR diminishes significantly with increasing outside FOV activity, in the range explored. ESD and Ac,out have a similar weight in accounting for CNR variance. Thus, an experimental law that adjusts the scan duration to the outside FOV activity can be devised. Recovery of CNR loss due to an elevated Ac,out activity seems feasible by modulating the ESD in individual bed positions according to Ac,out.

AIMS AND BACKGROUND:Following the widespread use of radioguided surgery (RGS) in melanoma and breast cancer, we applied this new surgical strategy to prostate cancer (PC). The aims of this study were 1) to evaluate the accuracy of RGS in the detection of prostatic sentinel lymph nodes (SLN), and 2) to verify if pelvic lymphadenectomy (LAD) is an accurate means to detect solitary micrometastases.STUDY DESIGN:We investigated 48 patients with PC confirmed by transrectal biopsy who underwent radical prostatectomy and bilateral LAD. A dose of 99mTc-labeled nanocolloid particles was injected into the prostate after needle positioning by ultrasonography. Serial imaging was obtained with a gamma camera, identifying 1) the first radioactive lymph node (sentinel lymph node, SLN); 2) other radioactive lymph nodes, and 3) non-active lymph nodes.RESULTS:Forty-three SLNs were identified in 48 patients. Twenty SLNs were located at unusual sites with respect to the extent of conventional LAD. Five SLNs were positive for micrometastases and two of these were located outside the usual LAD area. No micrometastases were found in any of the remaining lymph nodes (active and non-active).CONCLUSIONS:These preliminary results are in agreement with the few previous scientific contributions available on this topic and indicate that it is possible to reduce the extent and duration of surgery and necessary to reevaluate the conventional sites of lymphatic drainage.