Automatic quality measurement of aortic contrast-enhanced CT angiographies for patient-specific dose optimization

Abstract Purpose Iodine-containing contrast agent (CA) used in contrast-enhanced CT angiography (CTA) can pose a health risk for patients. A system that adjusts the frequently used standard CA dose for individual patients based on their clinical parameters can be useful. As basis the quality of the image contrast in CTA volumes has to be determined, especially to recognize excessive contrast induced by CA overdosing. However, a manual assessment with a ROI-based image contrast classification is a time-consuming step in everyday clinical practice. Methods We propose a method to automate the contrast measurement of aortic CTA volumes. The proposed algorithm is based on the mean HU values in selected ROIs that were automatically positioned in the CTA volume. First, an automatic localization algorithm determines the CTA image slices for certain ROIs followed by the localization of these ROIs. A rule-based classification using the mean HU values in the ROIs categorizes images with insufficient, optimal and excessive contrast. Results In 95.89% (70 out of 73 CTAs obtained with the ulrich medical CT motion contrast media injector) the algorithm chose the same image contrast class as the radiological expert. The critical case of missing an overdose did not occur with a positive predicative value of 100%. Conclusion The resulting system works well within our range of considered scan protocols detecting enhanced areas in CTA volumes. Our work automized an assessment for classifying CA-induced image contrast which reduces the time needed for medical practitioners to perform such an assessment manually.

Download Full-text

Main pulmonary artery diameter assessment in a large sample of Indian population: a MDCT based study

International Journal of Scientific Reports ◽

10.18203/issn.2454-2156.intjscirep20192064 ◽

2019 ◽

Vol 5 (6) ◽

pp. 145

Author(s):

Abdul Haseeb Wani ◽

Yassar Shiekh ◽

Najeeb Tallal Ahangar

Keyword(s):

Pulmonary Artery ◽

Main Pulmonary Artery ◽

Normative Values ◽

Contrast Enhanced Ct ◽

Contrast Enhanced ◽

Enhanced Ct ◽

Significant Difference ◽

Pulmonary Arterial ◽

The Mean ◽

Pulmonary Artery Diameter

Background: The gold standard for pulmonary artery pressure measurement is right heart catheterization but its invasive nature precludes its routine use. Main pulmonary arterial trunk calibre increase is a strong indicator of underlying pulmonary arterial hypertension. MDCT can accurately measure the diameter of main pulmonary artery. The objective of the study was to establish the normative values of main pulmonary artery caliber using contrast enhanced CT and try to ascertain any significant difference in main pulmonary artery calibers between two genders and correlation of age and main pulmonary artery diameter.Methods: Contrast enhanced CT images of 462 subjects were analysed on a PACS workstation monitor and widest diameter perpendicular to long axis of the main pulmonary artery as seen on reformatted axial image was measured with electronic caliper tool at the level of the main pulmonary artery bifurcation. Results: The mean main pulmonary artery diameter in females was 22.54±2.19 mm and 23.34±3.06 mm in males. The mean pulmonary artery diameter in males was larger than females with statistically significant difference seen (p<0.05). The correlation coefficient between age of whole sample and their mean main pulmonary artery was found to be 0.1006 with no statistically significant difference.Conclusions: There is a statistically significant difference in the mean main pulmonary artery calibre between males and females with no strong correlation between the age and mean main pulmonary artery calibre. Further studies are warranted to find the complex interaction between main pulmonary artery diameter and sex, age and body mass index.

Download Full-text

A liver segmentation approach in contrast-enhanced CT images with patient-specific knowledge

10.1117/12.878742 ◽

2011 ◽

Cited By ~ 1

Author(s):

Ahmed Afifi ◽

Toshiya Nakaguchi ◽

Norimichi Tsumura

Keyword(s):

Ct Images ◽

Patient Specific ◽

Liver Segmentation ◽

Specific Knowledge ◽

Contrast Enhanced Ct ◽

Contrast Enhanced ◽

Enhanced Ct ◽

Segmentation Approach

Download Full-text

Visibility of the hilar lymph nodes using advanced virtual monoenergetic low-keV images for preoperative evaluation of lung cancer

British Journal of Radiology ◽

10.1259/bjr.20180734 ◽

2019 ◽

Vol 92 (1103) ◽

pp. 20180734

Author(s):

Tomoya Sekiguchi ◽

Yoshiyuki Ozawa ◽

Masaki Hara ◽

Motoo Nakagawa ◽

Taeko Goto ◽

...

Keyword(s):

Lung Cancer ◽

Contrast Media ◽

Ct Number ◽

Contrast Enhanced Ct ◽

Contrast Enhanced ◽

Enhanced Ct ◽

Group A ◽

The Mean ◽

Group B ◽

Delayed Phase

Objective: The purpose of our study was to evaluate the visibility of the hilar lymph nodes (LNs) using advanced virtual monoenergetic low-keV images compared with early-phase contrast-enhanced CT. Methods: Dual energy contrast-enhanced CT was performed for pre-operative evaluation of lung cancer at 20 and 60 s after administration of contrast media in 50 patients (32 males and 18 females; mean age, 69 years). Five kinds of images (A: 20 s/120 kV; B: 60 s/40 keV; C: 60 s/50 keV; D: 60 s/120 kV; E: 60 s/100 kV) were reconstructed. We measured the CT number of the bilateral main pulmonary arteries (PAs), pulmonary veins (PVs) and hilar LNs, and evaluated the differences in CT number (Hounsfield units, HUs) between the PA/PV and LNs (PA–LN and PV–LN contrast). Artifacts from the superior vena cava (SVC) were also evaluated. Results: The mean PA–LN contrast (HU) was 415 in image group A, 299 in B, 180 in C, 80 in D, and 100 in E. The mean PV–LN contrasts in each group were 306, 287, 177, 78, and 99, respectively. Image group B showed the second highest PA–LN contrast following image group A. There was no significant difference in the PV–LN contrast between image groups A and B. The PA–LN and PV–LN contrasts of image groups B and C were significantly higher than those of E. SVC artifacts were lower in the delayed-phase images (Group B–E) than in Group A. Conclusion: To evaluate the hilar LNs with a single image series, advanced virtual monoenergetic 40-keV imaging at the delayed 60-s phase seems to be the most valuable. Advances in knowledge: Advanced virtual monoenergetic image is useful for evaluation of both hilar LNs and tumors in the delayed phase without artifact derived from the streak artifact from dense contrast media in the SVC.

Download Full-text