Iterative reconstruction algorithm improves the image quality without affecting quantitative measurements of computed tomography perfusion in the upper abdomen
“…Woisetschläger et al . ( 14 ) evaluated CT perfusion examinations of the upper abdomen to assess differences in image quality between FBP and ADMIRE Strengths 3, 4 and 5. Quantitative measurements of blood flow, blood volume and time to peak, arterial liver perfusion, portal venous liver perfusion and hepatic perfusion index were generated by placing identical sized ROIs in identical positions in the following tissues; left liver lobe, right liver lobe, hepatocellular carcinoma, spleen, gastric wall, pancreas and portal vein for all four reconstruction types using the maximum-slope model.…”
Section: Resultsmentioning
confidence: 99%
“…Image quality can be assessed both quantitatively and qualitatively: some of the reviewed publications have included both quantitative and qualitative assessments ( 6 , 8 , 9 , 12 , 13 , 15–17 ) and some only quantitative ( 14 , 16 , 18 , 20 ) or qualitative ( 10 ) assessments. It is apparent from the review that noise reduction measurements cannot be directly transferred into potential dose reduction as IR algorithms are subject to change in noise texture particularly at lower radiation doses, which ultimately affects image quality ( 15 ) .…”
Traditional filtered back projection (FBP) reconstruction methods have served the computed tomography (CT) community well for over 40 years. With the increased use of CT during the last decades, efforts to minimise patient exposure, while maintaining sufficient or improved image quality, have led to the development of model-based iterative reconstruction (MBIR) algorithms from several vendors. The usefulness of the advanced modeled iterative reconstruction (ADMIRE) (Siemens Healthineers) MBIR in abdominal CT is reviewed and its noise suppression and/or dose reduction possibilities explored. Quantitative and qualitative methods with phantom and human subjects were used. Assessment of the quality of phantom images will not always correlate positively with those of patient images, particularly at the higher strength of the ADMIRE algorithm. With few exceptions, ADMIRE Strength 3 typically allows for substantial noise reduction compared to FBP and hence to significant (≈30%) patient dose reductions. The size of the dose reductions depends on the diagnostic task.
“…Woisetschläger et al . ( 14 ) evaluated CT perfusion examinations of the upper abdomen to assess differences in image quality between FBP and ADMIRE Strengths 3, 4 and 5. Quantitative measurements of blood flow, blood volume and time to peak, arterial liver perfusion, portal venous liver perfusion and hepatic perfusion index were generated by placing identical sized ROIs in identical positions in the following tissues; left liver lobe, right liver lobe, hepatocellular carcinoma, spleen, gastric wall, pancreas and portal vein for all four reconstruction types using the maximum-slope model.…”
Section: Resultsmentioning
confidence: 99%
“…Image quality can be assessed both quantitatively and qualitatively: some of the reviewed publications have included both quantitative and qualitative assessments ( 6 , 8 , 9 , 12 , 13 , 15–17 ) and some only quantitative ( 14 , 16 , 18 , 20 ) or qualitative ( 10 ) assessments. It is apparent from the review that noise reduction measurements cannot be directly transferred into potential dose reduction as IR algorithms are subject to change in noise texture particularly at lower radiation doses, which ultimately affects image quality ( 15 ) .…”
Traditional filtered back projection (FBP) reconstruction methods have served the computed tomography (CT) community well for over 40 years. With the increased use of CT during the last decades, efforts to minimise patient exposure, while maintaining sufficient or improved image quality, have led to the development of model-based iterative reconstruction (MBIR) algorithms from several vendors. The usefulness of the advanced modeled iterative reconstruction (ADMIRE) (Siemens Healthineers) MBIR in abdominal CT is reviewed and its noise suppression and/or dose reduction possibilities explored. Quantitative and qualitative methods with phantom and human subjects were used. Assessment of the quality of phantom images will not always correlate positively with those of patient images, particularly at the higher strength of the ADMIRE algorithm. With few exceptions, ADMIRE Strength 3 typically allows for substantial noise reduction compared to FBP and hence to significant (≈30%) patient dose reductions. The size of the dose reductions depends on the diagnostic task.
“…In our study, the SNR of pancreatic parenchyma, GDA, ASPDA, and DPA in 40-keV MEI (+) increased by 58.14%, 50.76%, 38.66%, and 39.20%, respectively, compared with PEI. Moreover, an advanced modeled iterative reconstruction was applied for DECT to suppress the image noise and improve image quality [ 18 , 19 ]. All these reasons may contribute to the better image quality at 40-keV MEI (+) than PEI.…”
Background
Pancreatic ductal adenocarcinoma (PDAC) remains a malignancy with poor prognosis, appropriate surgical resection and neoadjuvant therapy depend on the accurate identification of pancreatic supplying arteries. We aim to evaluate the ability of monoenergetic images (MEI [+]) of dual-energy CT (DECT) to improve the visualization of pancreatic supplying arteries compared to conventional polyenergetic images (PEI) and investigate the implications of vascular variation in pancreatic surgery and transarterial interventions.
Results
One hundred patients without pancreatic diseases underwent DECT examinations were retrospectively enrolled in this study. The signal-to-noise ratio (SNR) and contrast-to-noise ratio (CNR) at 40-keV MEI (+) were significantly higher than those of PEI (p < 0.05). All subjective MEI (+) scores were significantly higher than those of PEI (p < 0.05). The visualization rates were significantly higher for posterior superior pancreaticoduodenal artery (PSPDA), anterior and posterior inferior pancreaticoduodenal artery (AIPDA, PIPDA), anterior and posterior pancreaticoduodenal arcade (APAC, PPAC), transverse and caudal pancreatic artery (TPA, PCA) at 40-keV MEI (+) than those of PEI (p < 0.05). However, there were no significant differences for visualizing anterior superior pancreaticoduodenal artery (ASPDA), inferior pancreaticoduodenal artery (IPDA), dorsal and magnificent pancreatic artery (DPA, MPA) between 40-keV MEI (+) and PEI (p > 0.05). Four types of variations were observed in the origin of DPA and three to five types in the origin of PSPDA, AIPDA and PIPDA.
Conclusions
40-keV MEI (+) of DECT improves the visualization and objective and subjective image quality of pancreatic supplying arteries compared to PEI. Pancreatic supplying arteries have great variations, which has important implications for preoperative planning of technically challenging surgeries and transarterial interventions.
“…Images were reconstructed using Advanced Modeled Iterative Reconstruction (ADMIRE)—an iterative postprocessing algorithm [ 16 ], a slice thickness of 3 mm, and convolution kernel of Bv40. Image stacks of the 4-phase CT and CTP scans were generated using ADMIRE 3 and 4, respectively ( Figure 1 ).…”
Section: Methodsmentioning
confidence: 99%
“…Image stacks of the 4-phase CT and CTP scans were generated using ADMIRE 3 and 4, respectively ( Figure 1 ). The latter ADMIRE grade was selected based on preliminary data showing that it yields an image quality roughly comparable to that of 4-phase scans with ADMIRE 3 reconstruction [ 16 ]. Figure 1 Contrast-enhanced cross-sectional images of abdominal 4-phase CT with A) arterial and B) PV phase and reconstructed images from CTP with C) A-CTP and D) PV-CTP phases.…”
Purpose
The aim of this study was to assess the image quality and diagnostic performance of reconstructed arterial (A) and portal venous (PV) phases in computed tomography perfusion (CTP) scans compared to the corresponding phases in standard 4-phase CT and to assess the utility for LI-RADS classification using CTP and 4-phase 4CT.
Methods
A total of 26 scans with each method (CTP and 4-phase CT) from 19 hepatocellular carcinoma patients were analyzed and compared. Arterial and PV phases reconstructed by advanced modeled iterative reconstruction at strength 4 (ADMIRE 4) from raw CTP data were compared with image sets from arterial and PV phases of 4-phase CT (ADMIRE 3) in the same patient with respect to image quality.
Results
Quantitative image analysis showed that reconstructed CTP datasets were equivalent to 4-phase CT image sets. Qualitative image analysis revealed similar lesion detection rates with the 2 methods for patients with an abdominal diameter ≤36 cm and body weight <90 kg, but lower detection rates with CTP for patients with an abdominal diameter >37 cm. There was no difference in Liver Imaging Reporting and Data System (LI-RADS) classifications between the 2 methods.
Conclusion
Reconstructed CTP images can potentially replace 4-phase CT images in patients weighing <90 kg and with a body diameter <37 cm, as the 2 methods are comparable in terms of quantitative image quality and ability to detect and classify lesions based on LI-RADS criteria.
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