Determination of lowest possible contrast volume in computed tomography pulmonary angiography by using pulmonary transit time.

PURPOSE: The aim of this study was to assess the effectiveness of the modified test-bolus (mTB) method in computed tomography pulmonary angiography (CTPA). MATERIALS AND METHODS: The Institutional Review Board approved this retrospective study. We reviewed 24 patients (nine men, 15 women; age range, 21-88 years) in whom CTPA was performed either by Bolus-Tracking (BT) (n = 12) or mTB (n = 12) methods. Pulmonary transit time (PTT) was used to determine scan delay time and contrast volume in the mTB group. The contrast volume, radiation dose, quantitative measures, and qualitative scores of enhancement were compared. The chi-squared test, Mann-Whitney U test, and κ statistics were used. The significance level was 0.05. RESULTS: The effective dose (P = 0.028) and contrast volume (P < 0.001) was significantly lower in the mTB group than those in the BT group. The difference in the quantitative measures and qualitative scores of enhancement between groups was statistically insignificant (P = 0.729, P = 0.635, respectively). Significantly fewer artefacts were observed in the mTB group (P = 0.024). CONCLUSION: By taking into account PTT, mTB appears to be a promising method for tailoring CTPA to the patient with the use of less contrast material and resulting in fewer artifacts.

Quantitative and qualitative comparison of standard-dose and low-dose pediatric head computed tomography: a retrospective study assessing the effect of adaptive statistical iterative reconstruction.

OBJECTIVES: Our aim was to assess the effect of adaptive statistical iterative reconstruction (ASIR) on pediatric head computed tomography (CT) examinations. METHODS: We retrospectively reviewed 305 pediatric head CT examinations. The study population consisted of standard dose (STD, n = 152) examinations reconstructed with filtered back projection and low dose (LD, n = 153) examinations reconstructed with 30% (LD30) and 0% (LD0) ASIR. We compared groups by means of radiation dose, noise measures, and visual grading. Student t test, 1-way analysis of variance test, and Mann-Whitney U test were used for statistical analysis. RESULTS: The dose in the LD30 group was significantly lower (29%) than that in the STD group (P < 0.001). The noise in the white matter (P < 0.001), SNR (P < 0.001), and subjective image noise (P = 0.044) was significantly better in the STD group than those in the LD30 group. There was no significant difference between LD30 and STD groups in the sharpness (P = 0.141), diagnostic acceptability (P = 0.079), and artifacts (P = 0.750) and contrast-to-noise ratio (P = 0.718). CONCLUSIONS: In conclusion, we found that a blend of 30% ASIR in a 16-slice multidetector CT produces diagnostically acceptable pediatric head CT examinations with a 29% less dose.

[Turkish as a scientific language]. / Bilim dili Türkçe.

In this article, Turkish is evaluated as a science language and the efforts of TUBA (Turkish Academy of Sciences) on the subject are mentioned.

[Assessment of mandibular vascular canals by dental CT]. / Mandibulanin lingual vasküler kanallarinin dental BT ile degerlendirilmesi.

PURPOSE: Sublingual artery and its branches run in the floor of the mouth and prone to substantial bleeding when injured during an implantation procedure. These branches enter the mandible from the lingual side and run through bony canals in the mandible. The purpose of this investigation is to evaluate the frequency, diameter, direction and position of lingual canals by dental CT. MATERIALS AND METHODS: 26 patients who underwent dental CT of the mandible before implantation were included in this study. Tomographic examination was performed in a transverse plane parallel to the mandibular base by bone algorithm. Multiplanar reconstructions were obtained in the sagittal and coronal oblique planes. RESULTS: All patients demonstrated at least one canal, and 8 patients had two or more canals. Two of the patients presented with four canals. The typical lingual canal locations were the middle of the mandible and the premolar regions. The mean diameter of the lingual canals was 0.8 mm +/- 0.2 mm in the middle, 0.6 mm +/- 0.1 mm in the premolar regions. The direction of median canal was anterior and slightly caudal. Lateral canals were directed in a medial manner. CONCLUSION: Before the dental implantation procedure, beside the relationships of implant with the important anatomic structures, lingual vascular canals should also be evaluated. Dental CT examination easily demonstrates the presence, position, direction and size of the lingual canals. By ensuring that radiologists and dentists are aware of these canals and their importance, bleeding complications during the placement of implants could be avoided.

Comparison of conventional sonography, real-time compound sonography, tissue harmonic sonography, and tissue harmonic compound sonography of abdominal and pelvic lesions.

OBJECTIVE: The purpose of this study was to compare conventional sonography, real-time spatial compound sonography, tissue harmonic sonography, and tissue harmonic sonography merged with compound sonography for overall image quality, lesion conspicuity, and elimination of artifacts. SUBJECTS AND METHODS. In this study, 150 lesions in 122 randomly selected patients with various abdominal and pelvic lesions were evaluated. For each lesion, sonograms were obtained with four techniques: conventional sonography, real-time spatial compound sonography, tissue harmonic sonography, and tissue harmonic compound sonography. All images were reviewed and graded independently by two observers for overall image quality, lesion conspicuity, and elimination of artifacts. RESULTS: Statistical analysis showed that for overall image quality, lesion conspicuity, and elimination of artifacts, tissue harmonic compound sonography was significantly superior to all of the other techniques; real-time spatial compound sonography was better than tissue harmonic sonography; and conventional sonography was the least valuable of all (p < 0.001). When data were analyzed separately according to lesion types, tissue harmonic compound sonography was significantly superior for revealing stone diseases, liver cysts, gallbladder polyps, and uterine myomas. For the remainder of lesion groups, spatial compounding was superior to tissue harmonic sonography for all aspects of evaluation, and conventional sonography was the least valuable (p < 0.05). CONCLUSION: In abdominal and pelvic scanning, tissue harmonic compound sonography provides the best overall image quality, best lesion conspicuity, and least artifacts of all the evaluated imaging modes. Spatial compound sonography is better than tissue harmonic sonography for the evaluation of lesions in general, despite some differences among lesion groups.

Lung at thin-section CT: influence of multiple-segment reconstruction on image quality.

PURPOSE: To evaluate multiple-segment reconstruction to reduce cardiac-motion artifacts on thin-section computed tomographic (CT) images in the lung. MATERIALS AND METHODS: Fifty patients were enrolled in the study. All images were obtained with a scanner capable of 1-second revolution time. Routine lung thin-section CT examination was performed with images reconstructed with bone algorithm. Multiple-segment images reconstructed with lung algorithm were obtained for three levels in the left paracardiac region. Segment images were reconstructed retrospectively with data for 225 degrees rotation rather than the 360 degrees rotation used for a complete scan. To minimize differences resulting from reconstruction algorithms, additional nonsegmented reconstruction was performed with lung algorithm. Three radiologists reviewed each set of images and assigned a quality score. Multiway analysis of variance was performed to compare motion artifact reduction with 225 degrees and 360 degrees reconstructions. RESULTS: Differences were not significant (P >.05) between scores for images reconstructed with bone or lung algorithms. Differences were significant between scores for reconstructed images obtained with the combination of 360 degrees bone and 225 degrees segment algorithms (P <.001) and for those obtained with the combination of 360 degrees lung and 225 degrees segment algorithms (P <.001). CONCLUSION: Multiple-segment reconstruction of lung thin-section CT images is an effective technique for reducing cardiac-motion artifacts without increasing patient dose.

Renal tuberculosis mimicking xanthogranulomatous pyelonephritis: ultrasonography, computed tomography and magnetic resonance imaging findings.

The incidence of tuberculosis has been increasing in recent years, and its treatment has also become challenging. The diagnosis of renal tuberculosis is often difficult and delayed. Early and correct diagnosis of tuberculosis with different organ system involvement is very important and can be easier with ultrasonography, computed tomography and/or magnetic resonance imaging. Although renal tuberculosis is the result of hematogenous spread more commonly from the lungs, less than 5%, of patients with urinary tract tuberculosis have active pulmonary disease. Renal tuberculosis may show variable radiological findings depending on the stage of the infection. Although an end-stage "autonephrectomized" kidey in tuberculosis is classically defined to be small in size, enlargement may on rare occasions be observed, which is the case in our patient. This form greatly mimics diffuse xanthogronulomatous pyelonephritis. Both diseases show thickening of the perirenal fasciae and spread of inflammation into the adjacent organs. Computed tomography and magnetic resonance imaging may show some specific features to differentiate these two entities.