The effect of respiratory-gated positron emission tomography/computed tomography in patients with pancreatic cancer.

Our aim of this study was to evaluate prospectively in patients with pancreatic cancer the effects of respiratory- gating during PET/CT acquisition on the determination of lesion volume and to measure tracer uptake. Our research included 36 patients diagnosed with pancreatic cancer. They underwent conventional whole-body PET/CT and subsequently respiratory-gated PET/CT of the upper abdomen. Based on list-mode PET acquisition data, respiratory-gated and non-gated images were created. Maximum standardized uptake values (SUVmax) and lesion volumes were compared between gated and non-gated images and also the rate of increase in SUVmax based on lesion size. Results showed that respiratory gating was successful in 34/36 patients. The median non-gated SUVmax was 6.2±2.1 and was 8.1±2.5 for respiratory- gated (P<0.01). Lesion volumes could be calculated in 27/34 patients. The median non-gated lesion volume was 5.82±5.57cm(3) and 4.31±4.56cm(3) for respiratory-gated (P<0.01). Furthermore, small lesions of ≤2cm had a significantly higher proportion of increased SUVmax compared to large lesions of >2cm (P=0.016). In conclusion, respiratory-gated PET/CT for patients with pancreatic cancer reduced respiratory motion artifacts and allowed significantly higher SUVmax to be obtained. In addition, the rate of increase in SUVmax tended to be higher in patients with pancreatic cancers of less or equal to 2cm diameter.

[Segmentation of Mass in Mammogram Using Gaze Search Patterns].

PURPOSE: It is very difficult for a radiologist to correctly detect small lesions and lesions hidden on dense breast tissue on a mammogram. Therefore, recently, computer-aided detection (CAD) systems have been widely used to assist radiologists in interpreting images. Thus, in this study, we aimed to segment mass on the mammogram with high accuracy by using focus images obtained from an eye-tracking device. METHODS: We obtained focus images for two mammography expert radiologists and 19 mammography technologists on 8 abnormal and 8 normal mammograms published by the DDSM. Next, the auto-encoder, Pix2Pix, and UNIT learned the relationship between the actual mammogram and the focus image, and generated the focus image for the unknown mammogram. Finally, we segmented regions of mass on mammogram using the U-Net for each focus image generated by the auto-encoder, Pix2Pix, and UNIT. RESULTS: The dice coefficient in the UNIT was 0.64±0.14. The dice coefficient in the UNIT was higher than that in the auto-encoder and Pix2Pix, and there was a statistically significant difference (p<0.05). The dice coefficient of the proposed method, which combines the focus images generated by the UNIT and the original mammogram, was 0.66±0.15, which is equivalent to the method using the original mammogram. CONCLUSION: In the future, it will be necessary to increase the number of cases and further improve the segmentation.

[Movement analysis of chest MR image under rest breath using realignment of SPM].

Analyses of diaphragm and chest wall motion are good indicators to evaluate clinical status and pulmonary function before and after surgery for respiratory disease. Noninvasive MR images using fast gradient recalled echo techniques recently have received a great deal of attention for their assessment of inspiratory motion. However, it is laborious to analyze a large number of dynamic MR images. Therefore, we performed movement analyses of chest 2D MR images by using the public domain software statistical parametric mapping(SPM)Realignment sub-routine, which is commonly used for the motion correction of brain functional MRI analyses. First, dynamic 2D MR images of a glue-stick phantom were measured as a simple reciprocal movement model and were numerically analyzed by the SPM Realignment. The resulting translation to each axis coincided with the measured values. Then the dynamic images of normal volunteers under free breathing were analyzed by the same method, and we found that the inspiratory motions were quantitatively shown as the translation to each axis. These results revealed that the SPM Realignment is a useful tool for screening the magnitude and characteristics of inspiratory motion.

Effect of lapatinib on hepatic parenchymal enhancement on gadoxetate disodium (EOB)-enhanced MRI scans of the rat liver.

PURPOSE: The purpose of this study was to investigate the effect of lapatinib treatment on hepatic parenchymal enhancement on Gd-EOB-MRI scans in rat. MATERIALS AND METHODS: Institutional animal review board approval was received prior to the commencement of all studies. Five rats received a single oral dose of 100 mg/kg/day lapatinib for 7 consecutive days. The controls (n = 5) were given 0.5 % (w/v) aqueous hydroxypropyl methyl cellulose containing 0.1 % (v/v) Tween 80 for 7 days. After the acquisition of gadoxetate disodium-enhanced MR images using 0.025 mmol gadolinium/kg, their livers were subjected to pathologic study to determine the expression level of organic anion-transporting polypeptide 1 (oatp1) and multi-drug resistance-associated protein 2 (mrp2). RESULTS: Relative enhancement of the liver was similar in both groups. At the hepatobiliary phase, which in rats occurs 3 min after the injection of Gd-EOB, it was 0.90 ± 0.06 in lapatinib-treated rats and 0.84 ± 0.08 in the controls (p = 0.30). There was also no difference in the expression level of oatp1 and mrp2. CONCLUSION: In rats, the administration of lapatinib for 7 days had no effect on hepatic parenchymal enhancement on Gd-EOB-MRI scans.