Effects of Model-Based Iterative Reconstruction in Low-Dose Paranasal Computed Tomography: A Comparison with Filtered Back Projection and Hybrid Iterative Reconstruction

Iterative reconstruction (IR) improves image quality compared with filtered back projection (FBP). This study investigated the usefulness of model-based IR (forward-projected model-based iterative reconstruction solution [FIRST]) in comparison with FBP and hybrid IR (adaptive iterative dose reduction three-dimensional processing [AIDR 3D]) in low-dose paranasal CT. Twenty-four patients with paranasal sinusitis who underwent standard-dose CT (120 kV) and low-dose CT (100 kV) scanning before and after medical treatment were enrolled. Standard-dose CT scans were reconstructed with FBP (FBP120), and low-dose CT scans with FBP (FBP100), AIDR 3D, and FIRST. The signal-to-noise ratio (SNR) and contrast-to-noise ratio (CNR) in three anatomical structures and effective doses were compared using Mann–Whitney U test. Two radiologists independently evaluated the visibility of 16 anatomical structures, overall image quality, and artifacts. Effective doses in lowdose CT were significantly reduced compared with those in standard-dose CT (0.24 vs 0.43 mSv, p<0.001). FIRST achieved significantly higher SNR (p<0.01, respectively) and CNR (p<0.001, respectively) of evaluated structures and significant improvement in overall image quality (p<0.001), artifacts (p<0.001), and visibility related to muscles (p<0.05) compared to FBP120, FBP100, and AIDR 3D. FIRST allowed radiation-dose reduction, while maintaining objective and subjective image quality in low-dose paranasal CT

Differences in Trocar Positioning within the Vertebral Body Using Two Different Positioning Methods: Effect on Trainee Performance

Purpose. To evaluate the educational effect of the Japanese Society of Interventional Radiology 7th Academic Summer Seminar from a technical perspective. Materials and Methods. Nineteen trainees participated in the seminar. The seminar consisted of vertebroplasty trainings using swine with the single-plane landmark method and with the ISOcenter Puncture (ISOP) method. All trainees were advised by an instructor as they operated the instruments and punctured the vertebra. For each trainee, the accuracy in the final position of the needle tip of the initial puncture in each swine training was evaluated. Results. Error in the final position of the needle tip of ≥5 mm from the target puncture site occurred in the lateral direction in 42% (8/19) of trainees with the landmark method and 5% (1/19) with the ISOP method. No error ≥5 mm occurred in the vertical or anteroposterior directions. In terms of puncture accuracy, error in the lateral direction was significantly lower with the ISOP method than with the landmark method (2.2 ± 1.5 mm versus 5.6 ± 3.2 mm). Conclusion. This seminar was effective training for trocar placement for beginners. The puncture was more accurate with the ISOP method than with the landmark method

General anesthetics cause mitochondrial dysfunction and reduction of intracellular ATP levels

<div><p>General anesthetics are indispensable for effective clinical care. Although, the mechanism of action of general anesthetics remains controversial, lipid bilayers and proteins have been discussed as their targets. In this study, we focused on the relationship between cellular ATP levels and general anesthetics. The ATP levels of nematodes and cultured mammalian cells were decreased by exposure to three general anesthetics: isoflurane, pentobarbital, and 1-phenoxy-2-propanol. Furthermore, these general anesthetics abolished mitochondrial membrane potential, resulting in the inhibition of mitochondrial ATP synthesis. These results suggest that the observed decrease of cellular ATP level is a common phenomenon of general anesthetics.</p></div

ATP level changes in Neuro2A cells by general anesthetics.

<p>ATP levels in Neuro2A cells were measured after each anesthetic treatment (<i>n</i> = 3). The values were normalized by protein concentration. The cells were treated with IF under saturated vapor pressure conditions. C, control treated without anesthetics for 30 min. Other anesthetics were added into the culture medium (0.3% 1PP, or 0.2% PBNa). The numbers under the graphs indicate the treatment time. Error bars indicate S.D. *<i>P</i> < 0.05, ANOVA with Bonferroni test vs control.</p

ATP imaging of Neuro2a cells during anesthetics treatments.

<p>(A) Live cell imaging after treatment with the indicated anesthetics. The YFP/CFP ratios in the cells are pseudo-colored. The number in each panel indicates the treatment time (min). The cells were treated in sealed boxes in the cases of IF (left top and bottom panels). In other cases, anesthetics added into the culture medium. (B) Time courses of the average YFP/CFP ratios of the Neuro2a cells expressing ATeam. The black and red lines indicate control (<i>n</i> = 31) and IF (saturated vapor pressure, <i>n</i> = 24) conditions, respectively. IF treatment was initiated at time 0 (min). (C) Black, blue, and green lines show control (<i>n</i> = 26), 1PP (0.2%, <i>n</i> = 9), and PBNa (0.2%, <i>n</i> = 32) treatment, respectively. Anesthetics were added at time 5 (min). Error bars indicate S.D.</p