Low-dose CT screening using hybrid iterative reconstruction: confidence ratings of diagnoses of simulated lesions other than lung cancer.

OBJECTIVE: To evaluate the confidence ratings of diagnoses of simulated lesions other than lung cancer on low-dose screening CT with hybrid iterative reconstruction (IR). METHODS: Simulated lesions (emphysema, mediastinal masses and interstitial pneumonia) in a chest phantom were scanned by a 320-row area detector CT. The scans were performed by 64-row and 160-row helical scans at various dose levels and were reconstructed by filtered back projection (FBP) and IR. Emphysema, honeycombing and reticular opacity were visually scored on a four-point scale by six thoracic radiologists. The ground-glass opacity as a percentage of total lung volume (%GGO), CT value and contrast-to-noise ratio (CNR) of mediastinal masses were calculated. These scores and values were compared between FBP and IR. Wilcoxon's signed-rank test was used (p < 0.05). Interobserver agreements were evaluated by κ statistics. RESULTS: There were no significant differences in visual assessment. Interobserver agreement was almost perfect. CT values were almost equivalent between FBP and IR, whereas CNR with IR was significantly higher than that with FBP. %GGO significantly increased at low-dose levels with FBP; however, IR suppressed the elevation. CONCLUSION: The confidence ratings of diagnoses of simulated lesions other than lung cancer on low-dose CT screening were not degraded with hybrid IR compared with FBP. ADVANCES IN KNOWLEDGE: Hybrid IR did not degrade the confidence ratings of diagnoses on visual assessment and differential diagnoses based on CT value of mediastinal masses, and it showed the advantage of higher GGO conspicuity at low-dose level. Radiologists can analyse images of hybrid IR alone on low-dose CT screening for lung cancer.

Safe and rapid contouring of fibro-osseous lesions in the orbital area using navigation with minimally invasive cranial bone registration.

BACKGROUND: Bone contouring is currently the best treatment for fibro-osseous lesions after bone growth arrest. Navigation systems available for this surgery allow intra-operative visualisation with improved cosmetic outcomes. However, conventional navigation systems using superficial skin registration cannot prevent subtle discrepancies. METHOD: To address this problem, we used a non-invasive cranial bone registration that uses patient-specific dental templates to maintain exact registration. We created the preset goal using the mirror image of the unaffected side for unilateral lesions, and using images obtained before the onset of symptoms for bilateral lesions. This system achieved precise pre-operative simulation. A sound aid in the navigation system provided information regarding proximity to critical structures and to the preset goal. RESULTS: We used this system to contour fibro-osseous lesions in three patients. All patients achieved good facial contours and improvement in symptoms. CONCLUSIONS: This method offers a safe, rapid surgical aid in treating orbital fibro-osseous lesions.

Evaluation of the extent of ground-glass opacity on high-resolution CT in patients with interstitial pneumonia associated with systemic sclerosis: comparison between quantitative and qualitative analysis.

AIM: To verify whether quantitative analysis of the extent of ground-glass opacity (GGO) on high-resolution computed tomography (HRCT) could show a stronger correlation with the therapeutic response of interstitial pneumonia (IP) associated with systemic sclerosis (SSc) compared with qualitative analysis. MATERIALS AND METHODS: Seventeen patients with IP associated with SSc received autologous peripheral blood stem cell transplantation (auto-PBSCT) and were followed up using HRCT and pulmonary function tests. Two thoracic radiologists assessed the extent of GGO on HRCT using a workstation. Therapeutic effect was assessed using the change of vital capacity (VC) and diffusing capacity of the lung for carbon monoxide (DLco) before and 12 months after PBSCT. Interobserver agreement was assessed using Spearman's rank correlation coefficient and the Bland-Altman method. Correlation with the therapeutic response between quantitative and qualitative analysis was assessed with Pearson's correlation coefficients. RESULTS: Spearman's rank correlation coefficient showed good agreement, but Bland-Altman plots showed that proportional error could be suspected. Quantitative analysis showed stronger correlation than the qualitative analysis based on the relationships between the change in extent of GGO and VC, and change in extent of GGO and DLco. CONCLUSION: Quantitative analysis of the change in extent of GGO showed stronger correlation with the therapeutic response of IP with SSc after auto-PBSCT than with the qualitative analysis.

Proper use of MR imaging in internal derangement of the knee (orthopedic surgeon's view).

MR imaging of the knee is a highly accurate examination in terms of the detection of meniscal tears and cruciate ligament ruptures among internal derangement of the knee. The overall accuracy in more than 2000 published cases reached nearly as high as 90% in meniscal tears, and 94% in anterior cruciate ligament (ACL) and 99% in posterior cruciate ligament (PCL) ruptures. Furthermore, the negative predictive value of the knee MR imaging, the number of true negative examination results divided by the numbers of true negative plus false-negative examination results, reaches almost 100% because of its very low false-negative rate. Therefore, from the orthopedic surgeon's point of view, even though the medical cost becomes a great concern, MR imaging has prime importance in the diagnosis of the internal derangement of the knee.

Dialyzing room disinfection with ultra-violet irradiation.

Infections represent a major problem in dialysis treatment, thus the dialyzing room should be kept abacterial as possible. We have installed 15-watt ultra-violet (U-V.) lamps for every 13.5 m2 on the ceiling for the purpose of the room disinfection and used them for 16 hours nightly after working hours. Bacteria were killed with over 10 hours irradiation even at the areas of low U-V. intensity where the irradiation may not be direct. This unexpected effectiveness might be from the influence of reflected rays and 03 produced. When half the lamps were turned on, the bacteriocidal effect was not sufficient in some areas. Any living organism with nucleic acids must be inactivated by this treatment, for the baceteriocidal effect is due to the nucleic acids injury. Furthermore, safety, readiness after the treatment, easy application and the negligible costs would make this method more advantageous to the other methods in room disinfection.