Diagnostic value of MRI versus 99Tcm-MDP bone scan in osseous metastasis of prostate cancer: a meta-analysis / 生物医学工程学杂志

This paper is aimed to assess the diagnostic value of MRI versus 99 Tcm-methylene diphosphonate (99 Tcm- MDP) bone scan (BS) for osseous metastases in patients with prostate cancer. The computer-based retrieval was conducted on PubMed, EMBASE, EBSCO, Web of Knowledge, the Cochrane Library and Ovid data bases to search for trials about diagnosing osseous metastases of prostate cancer with MRI and 99Tc"m-MDP BS. Selected with time acceptance and time exclusion criteria, the data quality were evaluated with QUADAS quality assessment tool and collected. We used the Meta-Disc software to conduct meta-analysis, and then calculated the pooled sensitivity, specificity and diagnostic odds ratio (DOR), drew the summary receiving operating characteristic (SROC) curve, and measured the area under curve (AUC) and Q value. Then five studies were included, involving 353 patients. The pooled sensitivity of MRI and BS was 0. 95 (95% CI 0. 90~0. 98) and 0. 67 (95% CI 0. 58~0. 75), respectively. The pooled specificity was 0. 97 (95% CI 0. 94~0. 99) and 0. 88 (95% CI 0. 83~0. 91), respectively. The pooled DOR was 402.99 (95% CI 119. 05 ~1364. 15) and 23. 85 (95% CI 1. 32~431. 48), respectively. The AUC was 0. 990 1 and 0. 624 1, respectively. The Q was 0. 958 7 and 0. 593 8. It can well be concluded that MRI is more effective than 99 Tcm-MDP BS in the diagnosis of osseous metastases in patients with prostate cancer.

Comparison of left ventricular function evaluation using gated myocardial perfusion imaging with different software of quantitative analysis / 生物医学工程学杂志

In the present study, the accuracy of the 4-dimensional model single photon emission computed tomography (4D-MSPECT) and quantitative gated single photon emission computed tomography (QGS) was investigated for assessing left ventricular end-diastolic (EDV), end-systolic volume (ESV) and ejection fraction (EF) from gated myocardial perfusion imaging (G-MPI) using left ventriculography (LVG) as reference. From December 2008 to June 2011, 85 patients, who underwent rest G-MPI and LVG (within 30 days) in West China Hospital, Sichuan University, were retrospectively recruited. EDV, ESV, and EF were calculated from G-MPI using 4D-MSPECT and QGS. Eighty-five patients (47 men, 38 women; age 57 +/- 13 years) were finally analyzed. Correlation between results of G-MPI and LVG was high for EDV, r = 0.89 (4D-MSPECT), r = 0.81 (QGS); ESV, r = 0.97 (4D-MSPECT), R = 0.95(QGS); EF, r = 0.95 (4D-MSPECT), r = 0.93 (QGS). 4D-MSPECT and QGS underestimated EDV significantly compared with LVG [(125 +/- 20) mL (4D-MSPECT), (118 +/- 39) mL (QGS), (131 +/- 33)mL (LVG)]. The ESV, 4D-MSPECT and QGS values did not differ significantly from LVG [(47 +/- 32) mL (4D-MSPECT), (53 +/- 29) mL (QGS), (49 +/- 37) mI (LVG)]. For LVEF, only QGS yielded values were significantly lower than LVG [61% +/- 21% (4D-MSPECT), 55% +/- 17% (QGS), and 63% +/- 19% (LVG)]. EDV, ESV, and EF as determined by 4D-MSPECT and QGS from G-MPI agree well with relevant values with LVG. However, Algorithm-inherent also showed slightly over- or under-estimation of volumes. Therefore, separated normal databases should be set up for each algorithm.

Influence of gated myocardial perfusion imaging with different acquisition models on the assessment of left ventricular function / 生物医学工程学杂志

This paper is aimed to investigate the influence of gated myocardial perfusion imaging (G-MPI) with 8- and 16-frame acquisition models on the assessment of left ventricular function. Patients prepared for stress and rest G-MPI were prospectively recruited from January 2010 to January 2011 in the Department of Nuclear Medicine of West China Hospital, Sichuan University. Two separate G-MPI studies, one with 8 and the other with 16 frames, were simultaneously acquired during a single gantry orbit using Concurrent Imaging technique. We calculated the left ventricular ejection fraction (EF) and volumes using the Auto Quant software. Forty-eight patients (29 men, 19 women; average age 51 +/- 16 years old) were finally analyzed. The differences in left ventricular EF between 8- and 16-frame were small: 3.27% (95% CI: 6.41%-0.12%) for post-stress and 3.13% (95% CI: 5.93%-0.32%) for rest. Both using 8 and 16 frames, there were significantly larger volumes and lower EF in patients with stress-induced ischemia than without. As for detecting left ventricular EF, 8-frame and 16-frame acquisition models should not be mutually alternated.

Objective and quantitative study on the effect of lossy JPEG2000 compression of nuclear medicine image / 生物医学工程学杂志

To objectively and quantitatively study the effect of JPEG2000 lossy compression of nuclear medicine image, line source images of various noise levels, actual quadrant-bar phantom images and simulated quadrant-bar phantom images of various noise levels were compressed using a JPEG2000 plug-in at 10 : 1 to 50 : 1 with a 10 : 1 step. Modulation transfer function (MTF), full width at half-maximum (FWHM) and the peak to total count ratio (PTCR) of line spread function of the simulated line source images were analyzed quantitatively. Image quality of the quadrant-bar phantom images was visually evaluated according to quality control procedures and the result was used to verify the quantitative analysis. It was observed that PTCR decreased as compression ratio increased and the higher the noise level, the faster PTCR decreased, which was in accordance with the increase of the width of the smallest bars that can be visually resolved in the actual quadrant-bar phantom images and simulated quadrant-bar phantom images. On the other hand, no significant change of MTF and FWHM was observed as compression ratio increased. It was concluded that PTCR may serve as an objectively quantitative metrics of image quality assessment.

Application study of JPEG2000 image compression in nuclear medicine / 生物医学工程学杂志

To study the usefulness of JPEG2000 compression for nuclear medicine (NM) image, normal and abnormal static images were compressed using a JPEG2000 plug-in. For lossless algorithm, the compressing ratio (CR) was calculated. For lossy algorithm, images were visually analyzed by NM physicians and ROC curves were generated. The area under ROC curve (AUC) was used as the index of image diagnostic quality. Paired sample t tests were performed to compare the AUCs. It was found that the lossless CR was (1.34+/-0.05) : 1. For lossy algorithm, the AUC decreased with the increase of CR. Comparison between the original and the compressed images revealed no significant difference for 10:1 CR but significant difference for bigger CRs. It was concluded that lossless compression has little usefulness for NM image because of very low CR. While lossy compression isused, the diagnostic quality of static NM images is preserved at CRs 50 : 1,40 : 1, 30 : 1,20 : 1 up to 10 : 1. For other types of NM image, CR should be increased or decreased according to their characteristics, especially the level of intrinsic statistical noise of NM image.