Type 2 Endoleaks: The Diagnostic Performance of Non-Specialized Readers on Arterial and Venous Phase Multi-Slice CT Angiography.

PURPOSE: To define the diagnostic precision of non-specialized readers in the detection of type 2 endoleaks (T2EL) in arterial versus venous phase acquisitions, and to evaluate an approach for radiation dose reduction. METHODS: The pre-discharge and final follow-up multi-slice CT angiographies of 167 patients were retrospectively analyzed. Image data were separated into an arterial and a venous phase reading set. Two radiology residents assessed the reading sets for the presence of a T2EL, feeding vessels, and aneurysm sac size. Findings were compared with a standard of reference established by two experts in interventional radiology. The effective dose was calculated. RESULTS: Overall, experts detected 131 T2ELs, and 331 feeding vessels in 334 examinations. Persistent T2ELs causing aneurysm sac growth > 5 mm were detected in 20 patients. Radiation in arterial and venous phases contributed to a mean of 58.6% and 39.0% of the total effective dose. Findings of reader 1 and 2 showed comparable sensitivities in arterial sets of 80.9 versus 85.5 (p = 0.09), and in venous sets of 73.3 versus 79.4 (p = 0.15), respectively. Reader 1 and 2 achieved a significant higher detection rate of feeding vessels with arterial compared to venous set (p = 0.04, p < 0.01). Both readers correctly identified T2ELs with growing aneurysm sac in all cases, independent of the acquisition phase. CONCLUSION: Arterial acquisitions enable non-specialized readers an accurate detection of T2ELs, and a significant better identification of feeding vessels. Based on our results, it seems reasonable to eliminate venous phase acquisitions

Correction: Type 2 Endoleaks: The Diagnostic Performance of Non-Specialized Readers on Arterial and Venous Phase Multi-Slice CT Angiography.

[This corrects the article DOI: 10.1371/journal.pone.0149725.]

Einfluss von Patientenvorbereitung und Kontrastmittel auf die Höhe der Herzfrequenz bei der CT des Herzens : Eine prospektive Studie aus radiologietechnologischer Perspektive

Zielsetzung: Hohe Herzfrequenzen (HF) während der CT-Angiographie (CTA) der Koronarien nehmen Einfluss auf Bildqualität und Patientendosis. Gründe für hohe HF können Ängste der Patienten und der Kontrastmittel-Bolus sein. Ob RadiologietechnologInnen einen Beitrag zur Erreichung der Zielfrequenz (HF65 bpm) leisten können, soll evaluiert werden. Methode: Bei 122 konsekutiven, prospektiv randomisierten Patienten wurde die Höhe der HF nach (1) Patienteninformation (persönliches Gespräch versus standardisiertes Informationsblatt) im Calzium-Scoring (CALZ), sowie während Applikation von (2) Kontrastmittel (Iomeprol 400mgJ/ml versus Iodixanol 320mgJ/ml) in der CTA gemessen. Als Ziel wurde eine HF65bpm definiert. Ergebnisse: 69% (n=84) erreichten die Zielherzfrequenz (65bpm) im CALZ. Von diesen 84 Patienten HF65 CALZ erreichten 66 (78%) auch während CTA die Zielherzfrequenz. Eine HF65bpm im CALZ stellte somit einen positiven Prädiktor für das Erreichen der HF65 während CTA dar. 22 (18%) Patienten mit HF>65bpm im CALZ erhielten eine i.v. Betablocker-Medikation. Davon erhielten 32% (n=7) zu 68% (n=15) eine Prämedikation in Abhängigkeit von der vorangegangenen Information (p0,05) bestand zwischen Iomeprol und Iodixanol in der CTA beim Vergleich der HF-Mittelwerte (n=122). Allerdings zeigte sich ein signifikanter HF-Anstieg mit Iomeprol (p=0,0001) in Bezug auf die individuelle HF zwischen CALZ und HF-CTA. Iodixanol zeigte diesbezüglich keine Signifikanz (p>0,05). Zusammenfassung: HF65bpm während CALZ war ein Prädiktor für HF65bpm während CTA. Die persönliche Patienteninformation zeigte an Patienten unter Stress eine positive Wirkung auf die HF im CALZ. Bei der Anwendung von Iomeprol stieg die HF mit Iodixanol konnte kein signifikanter HF-Anstieg während der CTA nachgewiesen werden. Weitere Studien an größeren Kollektiven zur Klärung des klinischen Benefit sind angezeigt.Objective: High heart rates (HR) are related to image quality and patient dose in computed tomography of the coronary arteries (CTA). Patient anxiety and contrast bolus may explain high HR. The question is whether radiographers make a contribution to receive the goal heart rate (HR65 bpm). Methods: In 122 consecutive prospective randomized patients HR after (1) patient information (one-to-one talk versus information-handout) in calcium scoring (CALC), and (2) during contrast application (Iomeprol 400mgI/ml versus Iodixanol 320mgI/mg) in CTA were measured. Goal heart rate - HR65bpm was defined. Results: 69% (n=84) patients received the goal HR65bpm in CALC. Among these 84 patients with CALZ-HR65bpm 66 (78%) also received the goal heart rate in CTA. Therefore HR65bpm in CALZ was a positive predictor for HR65bpm in CTA. 22 (18%) patients with HR>65bpm in CALC required i.v. betablocker medication. Among these 32% (n=7) in relation to 68% (n=15) received a premedication depending on the information before (p0,05) to HR-mean value was to notice with Iomeprol and Iodixanol in CTA (n=122). But a significant result with Iomeprol to HR increase (p=0,0001) in relation to individual HR in CALZ and HR in CTA was to notice. However there was no significance with Iodixanol (p>0,05). Conclusion: HR65bpm in CALZ was a significant predictor for HR65bmp in CTA. One-to-one talk with the patient before investigation showed a positive effect to HR-CALZ in patients with stress. With Iomprol HR increased in CTA but no significant HR increase was to notice with iodixanol. Evaluations in higher population might show clinical benefit.Wien, FH Campus Wien, Masterarb., 2010(VLID)315615

Low-dose high-pitch CT angiography of the supraaortic arteries using sinogram-affirmed iterative reconstruction.

OBJECTIVE: To prospectively evaluate image quality and radiation dose using a low-dose computed tomography angiography protocol and iterative image reconstruction for high-pitch dual-source CT-angiography (DSCTA) of the supraaortic arteries. MATERIAL AND METHODS: DSCTA was performed in 42 patients, using either 120 kVp tube voltage, 120 mAS tube current, 2.4 pitch and filtered back projection, or 100 kVp tube voltage, 100 mAs tube current, 3.2 pitch, and sinogram affirmed iterative reconstruction. Measurements of vessel attenuation, of the contrast-to-noise ratio (CNR) and the signal-to-noise ratio (SNR) were performed to objectively evaluate image quality. Two readers evaluated subjective image quality and image noise, using a four-point scale. Effective dose was used to compare the differences in radiation dose. RESULTS: Low-dose protocol application showed significantly higher vessel opacification (p = 0.013), and non-significantly higher CNR and SNR values. There was no difference in the subjective image quality and image noise reading between the protocols. Effective dose was significantly lower using the low-dose protocol (1.29 ± 0.21 mSv vs. 2.92 ± 0.72 mSv; p < 0.001). CONCLUSION: The combined use of reduced tube voltage, reduced tube current, and iterative reconstruction reduces radiation dose by 55.4% in high-pitch DSCTA of the supraaortic arteries without impairment of image quality

Correction: Type 2 Endoleaks: The Diagnostic Performance of Non-Specialized Readers on Arterial and Venous Phase Multi-Slice CT Angiography.

[This corrects the article DOI: 10.1371/journal.pone.0149725.]

Automated tube voltage selection in pediatric non-contrast chest CT.

BACKGROUND:Modern CT scanners provide automatic dose adjustment systems, which are promising options for reducing radiation dose in pediatric CT scans. Their impact on patient dose, however, has not been investigated sufficiently thus far. OBJECTIVE:To evaluate automated tube voltage selection (ATVS) in combination with automated tube current modulation (ATCM) in non-contrast pediatric chest CT, with regard to the diagnostic image quality. MATERIALS AND METHODS:There were 160 non-contrast pediatric chest CT scans (8.7±5.4 years) analyzed retrospectively without and with ATVS. Correlations of volume CT Dose Index (CTDIvol) and effective diameter, with and without ATVS, were compared using Fisher's z-transformation. Image quality was assessed by mean signal-difference-to-noise ratios (SDNR) in the aorta and in the left main bronchus using the independent samples t-test. Two pediatric radiologists and a general radiologist rated overall subjective Image quality. Readers' agreement was assessed using weighted kappa coefficients. A p value <0.05 was considered significant. RESULTS:CTDIvol correlation with the effective diameter was r = 0.62 without and r = 0.80 with ATVS (CI: -0.04 to -0.60; p = 0.025). Mean SDNR was 10.88 without and 10.03 with ATVS (p = 0.0089). Readers' agreement improved with ATVS (weighted kappa between pediatric radiologists from 0.1 (0.03-0.16) to 0.27 (0.09-0.45) with ATVS; between general and each pediatric radiologist from 0.1 (0.06-0.14) to 0.12 (0.05-0.20), and from 0.22 (0.11-0.34) to 0.36 (0.24-0.49)). CONCLUSION:ATVS, combined with ATCM, results in a radiation dose reduction for pediatric non-contrast chest CT without a loss of diagnostic image quality and prevents errors in manual tube voltage setting, and thus protecting larger children against an unnecessarily high radiation exposure

Multipath Curved Planar Reformations of Peripheral CT Angiography : Diagnostic Accuracy and Time Efficiency

Objectives To compare diagnostic performance and time efficiency between 3D multipath curved planar reformations (mpCPRs) and axial images of CT angiography for the pre-interventional assessment of peripheral arterial disease (PAD), with digital subtraction angiography as the standard of reference. Methods Forty patients (10 females, mean age 72 years), referred to CTA prior to endovascular treatment of PAD, were prospectively included and underwent peripheral CT angiography. A semiautomated toolbox was used to render mpCPRs. Twenty-one arterial segments were defined in each leg; for each segment, the presence of stenosis > 70% was assessed on mpCPRs and axial images by two readers, independently, with digital subtraction angiography as gold standard. Results Both readers reached lower sensitivity (Reader 1: 91 vs. 94%, p = 0.08; Reader 2: 89 vs. 93%, p = 0.03) but significantly higher specificity (Reader 1: 94 vs. 89%, p < 0.01; Reader 2: 96 vs. 95%, p = 0.01) with mpCPRs than with axial images. Reader 1 achieved significantly higher accuracy with mpCPRs (93 vs. 91%, p = 0.02), and Reader 2 had similar overall accuracy in both evaluations (94 vs. 94%, p = 0.96). Both readers read mpCPRs significantly faster than axial images (Reader 1: 5′45″ based on mpCPRs vs. 7′40″ based on axial images; Reader 2: 4′41″ based on mpCPRs vs. 6′57″ based on axial images; p < 0.01). Conclusions mpCPRs are a promising 3D reformation technique that facilitates a fast assessment of PAD with high diagnostic accuracy.(VLID)357824

Comparison of image quality at the thoracic outlet.

<p>Axial images with similar window setting (W900/L250) using the standard protocol and FBP (A) and at low-dose, using SAFIRE for image reconstruction (B). Both studies were rated having excellent diagnostic image quality. Higher vessel attenuation and reduced image noise is evident at low-dose and SAFIRE (B).</p