Low-Dose Abdominal CT Using a Deep Learning-Based Denoising Algorithm: A Comparison with CT Reconstructed with Filtered Back Projection or Iterative Reconstruction Algorithm

OBJECTIVE: To compare the image quality of low-dose (LD) computed tomography (CT) obtained using a deep learning-based denoising algorithm (DLA) with LD CT images reconstructed with a filtered back projection (FBP) and advanced modeled iterative reconstruction (ADMIRE).MATERIALS AND METHODS: One hundred routine-dose (RD) abdominal CT studies reconstructed using FBP were used to train the DLA. Simulated CT images were made at dose levels of 13%, 25%, and 50% of the RD (DLA-1, -2, and -3) and reconstructed using FBP. We trained DLAs using the simulated CT images as input data and the RD CT images as ground truth. To test the DLA, the American College of Radiology CT phantom was used together with 18 patients who underwent abdominal LD CT. LD CT images of the phantom and patients were processed using FBP, ADMIRE, and DLAs (LD-FBP, LD-ADMIRE, and LD-DLA images, respectively). To compare the image quality, we measured the noise power spectrum and modulation transfer function (MTF) of phantom images. For patient data, we measured the mean image noise and performed qualitative image analysis. We evaluated the presence of additional artifacts in the LD-DLA images.RESULTS: LD-DLAs achieved lower noise levels than LD-FBP and LD-ADMIRE for both phantom and patient data (all p < 0.001). LD-DLAs trained with a lower radiation dose showed less image noise. However, the MTFs of the LD-DLAs were lower than those of LD-ADMIRE and LD-FBP (all p < 0.001) and decreased with decreasing training image dose. In the qualitative image analysis, the overall image quality of LD-DLAs was best for DLA-3 (50% simulated radiation dose) and not significantly different from LD-ADMIRE. There were no additional artifacts in LD-DLA images.CONCLUSION: DLAs achieved less noise than FBP and ADMIRE in LD CT images, but did not maintain spatial resolution. The DLA trained with 50% simulated radiation dose showed the best overall image quality.

Usefulness of CT-Guided Percutaneous TransthoracicNeedle Lung Biopsies in Patients with SuspectedPulmonary Infection

Objective@#This study aimed to evaluate the clinical benefits and risks of CT-guided percutaneous transthoracic needle lung biopsies (PTNBs) in patients with a suspected pulmonary infection. @*Materials and Methods@#This study included 351 CT-guided PTNBs performed in 342 patients (mean age, 58.9 years [range,17–91 years]) with suspected pulmonary infection from January 2010 to December 2016. The proportion of biopsies that revealed the causative organism for pulmonary infection and that influenced patient’s treatment were measured. Multivariateanalyses were performed to identify factors associated with PTNB that revealed the causative organism or affected the treatment. Finally, the complication rate was measured. @*Results@#CT-guided PTNB revealed the causative organism in 32.5% of biopsies (114/351). The presence of necrotic components in the lesion (odds ratio [OR], 1.7; 95% confidence interval [CI], 1.1–2.7; p = 0.028), suspected pulmonary tuberculosis (OR, 2.0; 95% CI, 1.2–3.5; p = 0.010), and fine needle aspiration (OR, 2.5; 95% CI, 1.1–5.8; p = 0.037) were factors associated with biopsies that revealed the causative organism. PTNB influenced patient’s treatment in 40.7% (143/351) of biopsies. The absence of leukocytosis (OR, 1.9; 95% CI, 1.0–3.7; p = 0.049), presence of a necrotic component in the lesion (OR, 2.4; 95% CI, 1.5–3.8; p < 0.001), and suspected tuberculosis (OR, 1.7; 95% CI, 1.0–2.8; p = 0.040) were factors associated with biopsies that influenced the treatment. The overall complication rate of PTNB was 19% (65/351). @*Conclusion@#In patients with suspected pulmonary infection, approximately 30–40% of CT-guided PTNBs revealed the causative organism or affected the treatment. The complication rate of PTNB for suspected pulmonary infection was relatively low.

Evaluation of effects of olfactory and auditory stimulation on separation anxiety by salivary cortisol measurement in dogs

Separation anxiety (SA) is a serious behavioral problem in dogs. In this study, salivary cortisol was studied to determine if the owner's odor or voice could reduce SA in dogs. Twenty-eight dogs with SA were divided into three groups: group 1 (control), group 2 (with owner's clothes during the separation period; SP) and group 3 (a recording of the owner's voice was played during SP). The dog's saliva was collected after the owner and their dog were in the experimental room for 5 min (PRE). The dog was then separated from the owner for 20 min and saliva collected four times at intervals of 5 min (SP1-4). Finally, the owner was allowed back into the room to calm the dog for 5 min, after which saliva was collected (POST). Evaluation of salivary cortisol concentrations by ELISA revealed that the ratios of SP1 concentration to PRE or POST concentrations were significantly higher in group 1 than in group 2 or 3. Additionally, the concentrations of SP1-PRE and SP1-POST among groups differed significantly. These findings indicate that the owner's odor or voice may be helpful to managing stress in dogs with SA.

Culture of Dendritic Cell from Normal Peripheral Blood Monocyte and Its Anti-tumor Immune Activity When Pulsed by Renal Cell Carcinoma Cell Line: In vitro Study / 대한비뇨기과학회지

PURPOSE: Dendritic cells (DC) play a crucial role in the initiation of primary immune response and are known as an excellent adjuvant for anti-cancer immunity. In this study, we tried to obtain substantial numbers of DC from peripheral blood of normal volunteers. We also investigated the anti-tumor immune response of DC pulsed by renal cell carcinoma cell line A498 in vitro. MATERIALS AND METHODS: DC were generated by culturing plastic adherent mononuclear cells from the peripheral blood in the presence of granulocyte-macrophage colony- stimulating factor and interleukin-4. Immature DC were cocultured with T-cells and pulsed by A498. MTT analysis was performed using the medium in which A498 only was cultured as control. Our experiments were analyzed by means of a commercial IL-12 p70 ELISA (Quantikine; R & D Systems, Minneapolis, MN). The capture antibodies used in both tests specifically recognize the p70 heterodimer, but not the free p40 chains. Detection limits were 30pg/ml of IL-12. RESULTS: We could obtain 1.5-2.0x106 DC with phenotype typical of mature DC (CD14-, CD80+, and CD83+) from the normal peripheral blood. On T-cell proliferation assay, the number of T-cells increased in proportion to that of DC and when DC were pulsed by A498, the same phenomenon could be observed. DC and T-cell media with A498 tumor lysate showed more production of IL-12 on IL-12 p70 ELISA than the media without A498 tumor lysate. CONCLUSIONS: We could successfully obtain mature DC from the peripheral blood. The data revealed indirectly that DC treated with tumor lysate enhance immune activity and thereby increase the anti-cancer effect of T-cells. Further investigations including in-vivo study are necessary to realize the effect of immunotherapy using DC against metastatic renal cell carcinoma.