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  • 1.
    Coenen, Adriaan
    et al.
    Erasmus Univ, Netherlands.
    Kim, Young-Hak
    Univ Ulsan, South Korea.
    Kruk, Mariusz
    Inst Cardiol, Poland.
    Tesche, Christian
    Med Univ South Carolina, SC 29425 USA.
    De Geer, Jakob
    Linköpings universitet, Institutionen för medicin och hälsa, Avdelningen för radiologiska vetenskaper. Linköpings universitet, Medicinska fakulteten. Linköpings universitet, Centrum för medicinsk bildvetenskap och visualisering, CMIV. Region Östergötland, Diagnostikcentrum, Röntgenkliniken i Linköping.
    Kurata, Akira
    Ehime Univ, Japan.
    Lubbers, Marisa L.
    Erasmus Univ, Netherlands.
    Daemen, Joost
    Erasmus Univ, Netherlands.
    Itu, Lucian
    Siemens SRL, Romania.
    Rapaka, Saikiran
    Siemens Healthcare, NJ USA.
    Sharma, Puneet
    Siemens Healthcare, NJ USA.
    Schwemmer, Chris
    Siemens Healthcare GmbH, Germany.
    Persson, Anders
    Linköpings universitet, Institutionen för medicin och hälsa, Avdelningen för radiologiska vetenskaper. Linköpings universitet, Medicinska fakulteten. Region Östergötland, Diagnostikcentrum, Röntgenkliniken i Linköping. Linköpings universitet, Centrum för medicinsk bildvetenskap och visualisering, CMIV.
    Schoepf, U. Joseph
    Med Univ South Carolina, SC 29425 USA.
    Kepka, Cezary
    Inst Cardiol, Poland.
    Yang, Dong Hyun
    Univ Ulsan, South Korea.
    Nieman, Koen
    Erasmus Univ, Netherlands; Stanford Univ, CA 94305 USA.
    Diagnostic Accuracy of a Machine-Learning Approach to Coronary Computed Tomographic Angiography-Based Fractional Flow Reserve Result From the MACHINE Consortium2018Ingår i: Circulation Cardiovascular Imaging, ISSN 1941-9651, E-ISSN 1942-0080, Vol. 11, nr 6, artikel-id e007217Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Background: Coronary computed tomographic angiography (CTA) is a reliable modality to detect coronary artery disease. However, CTA generally overestimates stenosis severity compared with invasive angiography, and angiographic stenosis does not necessarily imply hemodynamic relevance when fractional flow reserve (FFR) is used as reference. CTA-based FFR (CT-FFR), using computational fluid dynamics (CFD), improves the correlation with invasive FFR results but is computationally demanding. More recently, a new machine-learning (ML) CT-FFR algorithm has been developed based on a deep learning model, which can be performed on a regular workstation. In this large multicenter cohort, the diagnostic performance ML-based CT-FFR was compared with CTA and CFD-based CT-FFR for detection of functionally obstructive coronary artery disease. Methods and Results: At 5 centers in Europe, Asia, and the United States, 351 patients, including 525 vessels with invasive FFR comparison, were included. ML-based and CFD-based CT-FFR were performed on the CTA data, and diagnostic performance was evaluated using invasive FFR as reference. Correlation between ML-based and CFD-based CT-FFR was excellent (R=0.997). ML-based (area under curve, 0.84) and CFD-based CT-FFR (0.84) outperformed visual CTA (0.69; Pamp;lt;0.0001). On a per-vessel basis, diagnostic accuracy improved from 58% (95% confidence interval, 54%-63%) by CTA to 78% (75%-82%) by ML-based CT-FFR. The per-patient accuracy improved from 71% (66%-76%) by CTA to 85% (81%-89%) by adding ML-based CT-FFR as 62 of 85 (73%) false-positive CTA results could be correctly reclassified by adding ML-based CT-FFR. Conclusions: On-site CT-FFR based on ML improves the performance of CTA by correctly reclassifying hemodynamically nonsignificant stenosis and performs equally well as CFD-based CT-FFR.

  • 2.
    De Geer, Jakob
    Linköpings universitet, Institutionen för medicin och hälsa, Avdelningen för radiologiska vetenskaper. Linköpings universitet, Medicinska fakulteten. Linköpings universitet, Centrum för medicinsk bildvetenskap och visualisering, CMIV.
    On the use of computed tomography in cardiac imaging2016Doktorsavhandling, sammanläggning (Övrigt vetenskapligt)
    Abstract [en]

    Background

    Cardiac Computed Tomography Angiography (CCTA) is becoming increasingly useful in the work‐up of coronary artery disease (CAD). Several potential methods for increasing the diagnostic yield of cardiac CT are available.

    Purpose

    Study I: To investigate whether the use of a 2‐D, non‐linear adaptive noise reduction filter can improve CCTA image quality.

    Study II: To evaluate the variation in adenosine stress dynamic CT perfusion (CTP) blood flow as compared to stress 99mTc SPECT. Secondly, to compare the perfusion results from manual and automatic myocardial CTP segmentation.

    Study III: To evaluate the accuracy of non‐invasive, CCTA‐derived Fractional Flow Reserve (cFFR).

    Study IV: To evaluate the prognostic value of CCTA in terms of major adverse cardiac events (MACE).

    Materials and methods

    Study I: Single images from 36 consecutive CCTA exams performed with two different dose levels were used. Image quality in full dose, low‐dose and noise‐reduced low‐dose images was graded using visual grading analysis. Image noise was measured.

    Study II: CTP and SPECT were performed in 17 patients, and the variation in per AHA‐segment blood flow was evaluated and compared. CTP results from manual and automated image segmentation were compared.

    Study III: CCTA datasets from 21 patients were processed using cFFR software and the results compared to the corresponding invasively measured FFR (invFFR).

    Study IV: 1205 consecutive patients with chest pain of unknown origin underwent CCTA. Baseline data and data on subsequent MACE were retrieved from relevant registries. Survival, hazard ratios and the three‐year incidence of cardiac events and readmissions were calculated.

    Results

    Study I: There was significant improvement in perceived image quality for all criteria when the filter was applied, and a significant decrease in image noise.

    Study II: The correlation coefficients for CTP vs. SPECT were 0.38 and 0.41 (p<0.001, for manual and automated segmentation respectively. Mean per patient CTP blood flow in normal segments varied between 94‐183 ml/100 ml tissue/min for manual segmentation, and 104‐196 ml/100 ml tissue/min for automated segmentation. The Spearman rank correlation coefficient for manual vs. automated segmentation CTP was ρ = 0.88 (p<0.001) and the Intraclass Correlation Coefficient (ICC) was 0.93 (p<0.001).

    Study III: The Spearman rank correlation coefficient for cFFR vs. invFFR was ρ = 0.77 (p<0.001) and the ICC was 0.73 (p<0.001). Sensitivity, specificity, positive predictive value and negative predictive value for significant stenosis (FFR<0.80, per vessel) were 0.83, 0.76, 0.56 and 0.93 respectively.

    Study IV: The hazard ratio for non‐obstructive CAD vs. normal coronary arteries was 5.13 (95% C.I 1.03‐25.43, p<0.05), and 151.40 (95% C.I 37.03‐619.08, p<0.001) for obstructive CAD vs. normal coronary arteries. The three‐year incidence of MACE was 1.1% for patients with normal vessels on CCTA, 2.5% for patients with non‐obstructive CAD and 42.7% for patients with obstructive CAD (p<0.001).

    Conclusions:

    Study I: Image quality and noise levels of low dose images were significantly improved with the filter, even though the improvement was small compared to the image quality of the corresponding diastolic full‐dose images.

    Study II: Correlation between dynamic CTP and SPECT was positive but weak. There were large variations in CTP blood flow in normal segments on SPECT, rendering the definition of an absolute cut‐off value for normal vs. ischemic myocardium difficult. Manual and automatic segmentation were equally useful.

    Study III: The correlation between cFFR and invFFR was good, indicating that noninvasively estimated cFFR performs on a similar level as invasively measure FFR.

    Study IV: The long‐term risk for MACE was very low in patients without obstructive CAD on CCTA, though there seemed to be a substantial increase in the risk for MACE even in patients with non‐obstructive CAD as compared to normal coronary arteries. In addition, even patients with normal coronary arteries or non‐obstructive CAD continued to have a substantial number of readmissions for chest pain or angina pectoris.

    Delarbeten
    1. The efficacy of 2D, non-linear noise reduction filtering in cardiac imaging: a pilot study
    Öppna denna publikation i ny flik eller fönster >>The efficacy of 2D, non-linear noise reduction filtering in cardiac imaging: a pilot study
    2011 (Engelska)Ingår i: Acta Radiologica, ISSN 0284-1851, E-ISSN 1600-0455, Vol. 52, nr 7, s. 716-722Artikel i tidskrift (Refereegranskat) Published
    Abstract [en]

    Background: Computed tomography (CT) is becoming increasingly popular as a non-invasive method for visualizing the coronary arteries but patient radiation doses are still an issue. Postprocessing filters such as 2D adaptive non-linear filters might help to reduce the dose without loss of image quality. less thanbrgreater than less thanbrgreater thanPurpose: To investigate whether the use of a 2D, non-linear adaptive noise reduction filter can improve image quality in cardiac computed tomography angiography (CCTA). less thanbrgreater than less thanbrgreater thanMaterial and Methods: CCTA examinations were performed in 36 clinical patients on a dual source CT using two patient dose levels: maximum dose during diastole and reduced dose (20% of maximum dose) during systole. One full-dose and one reduced-dose image were selected from each of the examinations. The reduced-dose image was duplicated and one copy postprocessed using a 2D non-linear adaptive noise reduction filter, resulting in three images per patient. Image quality was assessed using visual grading with three criteria from the European guidelines for assessment of image quality and two additional criteria regarding the left main artery and the overall image quality. Also, the HU value and its standard deviation were measured in the ascending and descending aorta. Data were analyzed using Visual Grading Regression and paired t-test. less thanbrgreater than less thanbrgreater thanResult: For all five criteria, there was a significant (P andlt; 0.01 or better) improvement in perceived image quality when comparing postprocessed low-dose images with low-dose images without noise reduction. Comparing full dose images with postprocessed low-dose images resulted in a considerably larger, significant (P andlt; 0.001) difference. Also, there was a significant reduction of the standard deviation of the HU values in the ascending and descending aorta when comparing postprocessed low-dose images with low-dose images without postprocessing. less thanbrgreater than less thanbrgreater thanConclusion: Even with an 80% dose reduction, there was a significant improvement in the perceived image quality when using a 2D noise-reduction filter, though not approaching the quality of full-dose images. This indicates that cardiac CT examinations could benefit from noise-reducing postprocessing with 2D non-linear adaptive filters.

    Ort, förlag, år, upplaga, sidor
    Informa Healthcare / Wiley-Blackwell / Royal Society of Medicine Press, 2011
    Nyckelord
    Cardiac, CT angiography, heart, adults, image manipulation
    Nationell ämneskategori
    Medicin och hälsovetenskap
    Identifikatorer
    urn:nbn:se:liu:diva-71803 (URN)10.1258/ar.2011.100511 (DOI)000295759600007 ()
    Tillgänglig från: 2011-11-04 Skapad: 2011-11-04 Senast uppdaterad: 2017-12-08
    2. Large variation in blood flow between left ventricular segments, as detected by adenosine stress dynamic CT perfusion.
    Öppna denna publikation i ny flik eller fönster >>Large variation in blood flow between left ventricular segments, as detected by adenosine stress dynamic CT perfusion.
    Visa övriga...
    2015 (Engelska)Ingår i: Clinical Physiology and Functional Imaging, ISSN 1475-0961, E-ISSN 1475-097X, Vol. 35, nr 4, s. 291-300Artikel i tidskrift (Refereegranskat) Published
    Abstract [en]

    BACKGROUND: Dynamic cardiac CT perfusion (CTP) is based on repeated imaging during the first-pass contrast agent inflow. It is a relatively new method that still needs validation.

    PURPOSE: To evaluate the variation in adenosine stress dynamic CTP blood flow as compared to (99m) Tc SPECT. Secondarily, to compare manual and automatic segmentation.

    METHODS: Seventeen patients with manifest coronary artery disease were included. Nine were excluded from evaluation for various reasons. All patients were examined with dynamic stress CTP and stress/rest SPECT. CTP blood flow was compared with SPECT on a per segment basis. Results for manual and automated AHA segmentation were compared.

    RESULTS: CTP showed a positive correlation with SPECT, with correlation coefficients of 0·38 and 0·41 for manual and automatic segmentation, respectively (P<0·0001). There was no significant difference between the correlation coefficients of the manual and automated segmentation procedures (P = 0·75). The average per individual global CTP blood flow value for normal segments varied by a factor of 1·9 (manual and automatic segmentation). For the whole patient group, the CTP blood flow value in normal segments varied by a factor of 2·9/2·7 (manual/automatic segmentation). Within each patient, the average per segment blood flow in normal segments varied by a factor of 1·3-2·0/1·2-2·1 (manual/automatic segmentation).

    CONCLUSION: A positive but rather weak correlation was found between CTP and (99m) Tc SPECT. Large variations in CTP blood flow suggest that a cut-off value for stress myocardial blood flow is inadequate to detect ischaemic segments. Dynamic CTP is hampered by a limited coverage.

    Nationell ämneskategori
    Klinisk medicin
    Identifikatorer
    urn:nbn:se:liu:diva-113400 (URN)10.1111/cpf.12163 (DOI)000356312800007 ()24842265 (PubMedID)
    Tillgänglig från: 2015-01-17 Skapad: 2015-01-17 Senast uppdaterad: 2017-12-05
    3. Software-based on-site estimation of fractional flow reserve using standard coronary CT angiography data.
    Öppna denna publikation i ny flik eller fönster >>Software-based on-site estimation of fractional flow reserve using standard coronary CT angiography data.
    Visa övriga...
    2016 (Engelska)Ingår i: Acta Radiologica, ISSN 0284-1851, E-ISSN 1600-0455, Vol. 57, nr 10, s. 1186-1192Artikel i tidskrift (Refereegranskat) Published
    Abstract [en]

    BACKGROUND: The significance of a coronary stenosis can be determined by measuring the fractional flow reserve (FFR) during invasive coronary angiography. Recently, methods have been developed which claim to be able to estimate FFR using image data from standard coronary computed tomography angiography (CCTA) exams.

    PURPOSE: To evaluate the accuracy of non-invasively computed fractional flow reserve (cFFR) from CCTA.

    MATERIAL AND METHODS: A total of 23 vessels in 21 patients who had undergone both CCTA and invasive angiography with FFR measurement were evaluated using a cFFR software prototype. The cFFR results were compared to the invasively obtained FFR values. Correlation was calculated using Spearman's rank correlation, and agreement using intraclass correlation coefficient (ICC). Sensitivity, specificity, accuracy, negative predictive value, and positive predictive value for significant stenosis (defined as both FFR ≤0.80 and FFR ≤0.75) were calculated.

    RESULTS: The mean cFFR value for the whole group was 0.81 and the corresponding mean invFFR value was 0.84. The cFFR sensitivity for significant stenosis (FFR ≤0.80/0.75) on a per-lesion basis was 0.83/0.80, specificity was 0.76/0.89, and accuracy 0.78/0.87. The positive predictive value was 0.56/0.67 and the negative predictive value was 0.93/0.94. The Spearman rank correlation coefficient was ρ = 0.77 (P < 0.001) and ICC = 0.73 (P < 0.001).

    CONCLUSION: This particular CCTA-based cFFR software prototype allows for a rapid, non-invasive on-site evaluation of cFFR. The results are encouraging and cFFR may in the future be of help in the triage to invasive coronary angiography.

    Ort, förlag, år, upplaga, sidor
    Sage Publications, 2016
    Nyckelord
    Cardiac; computed tomography angiography (CTA); heart; arteries; adults; computer applications – detection/diagnosis
    Nationell ämneskategori
    Radiologi och bildbehandling
    Identifikatorer
    urn:nbn:se:liu:diva-123579 (URN)10.1177/0284185115622075 (DOI)000382967500007 ()26691914 (PubMedID)
    Anmärkning

    Funding agencies: Department of Radiology, Region Ostergotland; Swedish Heart-Lung-foundation [20120449]

    Tillgänglig från: 2015-12-29 Skapad: 2015-12-29 Senast uppdaterad: 2017-12-01Bibliografiskt granskad
  • 3.
    De Geer, Jakob
    et al.
    Linköpings universitet, Institutionen för medicin och hälsa, Avdelningen för radiologiska vetenskaper. Linköpings universitet, Hälsouniversitetet. Linköpings universitet, Centrum för medicinsk bildvetenskap och visualisering, CMIV. Östergötlands Läns Landsting, Diagnostikcentrum, Röntgenkliniken i Linköping.
    Gjerde, Marcus
    Linköpings universitet, Institutionen för medicin och hälsa, Avdelningen för kardiovaskulär medicin. Linköpings universitet, Hälsouniversitetet. Östergötlands Läns Landsting, Hjärt- och Medicincentrum, Kardiologiska kliniken US. Linköpings universitet, Centrum för medicinsk bildvetenskap och visualisering, CMIV.
    Brudin, Lars
    Linköpings universitet, Institutionen för medicin och hälsa, Avdelningen för kardiovaskulär medicin. Linköpings universitet, Hälsouniversitetet. Department of Clinical Physiology in Kalmar, Linköping University, County Council of Kalmar, Kalmar, Sweden.
    Olsson, Eva
    Linköpings universitet, Institutionen för medicin och hälsa, Avdelningen för kardiovaskulär medicin. Linköpings universitet, Hälsouniversitetet. Östergötlands Läns Landsting, Hjärt- och Medicincentrum, Fysiologiska kliniken US. Linköpings universitet, Centrum för medicinsk bildvetenskap och visualisering, CMIV.
    Persson, Anders
    Linköpings universitet, Centrum för medicinsk bildvetenskap och visualisering, CMIV. Linköpings universitet, Institutionen för medicin och hälsa, Avdelningen för radiologiska vetenskaper. Linköpings universitet, Hälsouniversitetet. Östergötlands Läns Landsting, Diagnostikcentrum, Röntgenkliniken i Linköping.
    Engvall, Jan
    Linköpings universitet, Institutionen för medicin och hälsa, Avdelningen för kardiovaskulär medicin. Linköpings universitet, Hälsouniversitetet. Östergötlands Läns Landsting, Hjärt- och Medicincentrum, Fysiologiska kliniken US.
    Large variation in blood flow between left ventricular segments, as detected by adenosine stress dynamic CT perfusion.2015Ingår i: Clinical Physiology and Functional Imaging, ISSN 1475-0961, E-ISSN 1475-097X, Vol. 35, nr 4, s. 291-300Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    BACKGROUND: Dynamic cardiac CT perfusion (CTP) is based on repeated imaging during the first-pass contrast agent inflow. It is a relatively new method that still needs validation.

    PURPOSE: To evaluate the variation in adenosine stress dynamic CTP blood flow as compared to (99m) Tc SPECT. Secondarily, to compare manual and automatic segmentation.

    METHODS: Seventeen patients with manifest coronary artery disease were included. Nine were excluded from evaluation for various reasons. All patients were examined with dynamic stress CTP and stress/rest SPECT. CTP blood flow was compared with SPECT on a per segment basis. Results for manual and automated AHA segmentation were compared.

    RESULTS: CTP showed a positive correlation with SPECT, with correlation coefficients of 0·38 and 0·41 for manual and automatic segmentation, respectively (P<0·0001). There was no significant difference between the correlation coefficients of the manual and automated segmentation procedures (P = 0·75). The average per individual global CTP blood flow value for normal segments varied by a factor of 1·9 (manual and automatic segmentation). For the whole patient group, the CTP blood flow value in normal segments varied by a factor of 2·9/2·7 (manual/automatic segmentation). Within each patient, the average per segment blood flow in normal segments varied by a factor of 1·3-2·0/1·2-2·1 (manual/automatic segmentation).

    CONCLUSION: A positive but rather weak correlation was found between CTP and (99m) Tc SPECT. Large variations in CTP blood flow suggest that a cut-off value for stress myocardial blood flow is inadequate to detect ischaemic segments. Dynamic CTP is hampered by a limited coverage.

  • 4.
    De Geer, Jakob
    et al.
    Linköpings universitet, Centrum för medicinsk bildvetenskap och visualisering, CMIV. Linköpings universitet, Institutionen för medicin och hälsa, Medicinsk radiologi. Linköpings universitet, Hälsouniversitetet. Östergötlands Läns Landsting, Diagnostikcentrum, Röntgenkliniken i Linköping.
    Sandborg, Michael
    Linköpings universitet, Centrum för medicinsk bildvetenskap och visualisering, CMIV. Linköpings universitet, Institutionen för medicin och hälsa, Medicinsk radiofysik. Linköpings universitet, Hälsouniversitetet.
    Smedby, Örjan
    Linköpings universitet, Centrum för medicinsk bildvetenskap och visualisering, CMIV. Linköpings universitet, Institutionen för medicin och hälsa, Medicinsk radiologi. Linköpings universitet, Hälsouniversitetet. Östergötlands Läns Landsting, Diagnostikcentrum, Röntgenkliniken i Linköping.
    Persson, Anders
    Linköpings universitet, Centrum för medicinsk bildvetenskap och visualisering, CMIV. Linköpings universitet, Institutionen för medicin och hälsa, Medicinsk radiologi. Linköpings universitet, Hälsouniversitetet. Östergötlands Läns Landsting, Diagnostikcentrum, Röntgenkliniken i Linköping.
    Post processing noise reduction as a way of reducing the dose in cardiac CT without sacrificing image quality: A Pilot study.2010Ingår i: European Congress of Radiology 2010, 2010Konferensbidrag (Refereegranskat)
  • 5.
    de Geer, Jakob
    et al.
    Linköpings universitet, Institutionen för medicin och hälsa, Medicinsk radiologi. Linköpings universitet, Hälsouniversitetet. Linköpings universitet, Centrum för medicinsk bildvetenskap och visualisering, CMIV. Östergötlands Läns Landsting, Diagnostikcentrum, Röntgenkliniken i Linköping.
    Sandborg, Michael
    Linköpings universitet, Institutionen för medicin och hälsa, Medicinsk radiofysik. Linköpings universitet, Hälsouniversitetet. Östergötlands Läns Landsting, Centrum för kirurgi, ortopedi och cancervård, Radiofysikavdelningen US. Linköpings universitet, Centrum för medicinsk bildvetenskap och visualisering, CMIV.
    Smedby, Örjan
    Linköpings universitet, Institutionen för medicin och hälsa, Medicinsk radiologi. Linköpings universitet, Hälsouniversitetet. Östergötlands Läns Landsting, Diagnostikcentrum, Röntgenkliniken i Linköping. Linköpings universitet, Centrum för medicinsk bildvetenskap och visualisering, CMIV.
    Persson, Anders
    Linköpings universitet, Institutionen för medicin och hälsa, Medicinsk radiologi. Linköpings universitet, Hälsouniversitetet. Östergötlands Läns Landsting, Diagnostikcentrum, Röntgenkliniken i Linköping. Linköpings universitet, Centrum för medicinsk bildvetenskap och visualisering, CMIV.
    The efficacy of 2D, non-linear noise reduction filtering in cardiac imaging: a pilot study2011Ingår i: Acta Radiologica, ISSN 0284-1851, E-ISSN 1600-0455, Vol. 52, nr 7, s. 716-722Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Background: Computed tomography (CT) is becoming increasingly popular as a non-invasive method for visualizing the coronary arteries but patient radiation doses are still an issue. Postprocessing filters such as 2D adaptive non-linear filters might help to reduce the dose without loss of image quality. less thanbrgreater than less thanbrgreater thanPurpose: To investigate whether the use of a 2D, non-linear adaptive noise reduction filter can improve image quality in cardiac computed tomography angiography (CCTA). less thanbrgreater than less thanbrgreater thanMaterial and Methods: CCTA examinations were performed in 36 clinical patients on a dual source CT using two patient dose levels: maximum dose during diastole and reduced dose (20% of maximum dose) during systole. One full-dose and one reduced-dose image were selected from each of the examinations. The reduced-dose image was duplicated and one copy postprocessed using a 2D non-linear adaptive noise reduction filter, resulting in three images per patient. Image quality was assessed using visual grading with three criteria from the European guidelines for assessment of image quality and two additional criteria regarding the left main artery and the overall image quality. Also, the HU value and its standard deviation were measured in the ascending and descending aorta. Data were analyzed using Visual Grading Regression and paired t-test. less thanbrgreater than less thanbrgreater thanResult: For all five criteria, there was a significant (P andlt; 0.01 or better) improvement in perceived image quality when comparing postprocessed low-dose images with low-dose images without noise reduction. Comparing full dose images with postprocessed low-dose images resulted in a considerably larger, significant (P andlt; 0.001) difference. Also, there was a significant reduction of the standard deviation of the HU values in the ascending and descending aorta when comparing postprocessed low-dose images with low-dose images without postprocessing. less thanbrgreater than less thanbrgreater thanConclusion: Even with an 80% dose reduction, there was a significant improvement in the perceived image quality when using a 2D noise-reduction filter, though not approaching the quality of full-dose images. This indicates that cardiac CT examinations could benefit from noise-reducing postprocessing with 2D non-linear adaptive filters.

  • 6.
    De Geer, Jakob
    et al.
    Linköpings universitet, Institutionen för medicin och hälsa, Avdelningen för radiologiska vetenskaper. Linköpings universitet, Medicinska fakulteten. Linköpings universitet, Centrum för medicinsk bildvetenskap och visualisering, CMIV.
    Sandstedt, Mårten
    Linköpings universitet, Institutionen för medicin och hälsa, Avdelningen för radiologiska vetenskaper. Linköpings universitet, Medicinska fakulteten. Linköpings universitet, Centrum för medicinsk bildvetenskap och visualisering, CMIV.
    Björkholm, Anders
    Region Östergötland, Diagnostikcentrum, Röntgenkliniken i Linköping.
    Alfredsson, Joakim
    Linköpings universitet, Institutionen för medicin och hälsa, Avdelningen för kardiovaskulär medicin. Linköpings universitet, Medicinska fakulteten. Region Östergötland, Hjärt- och Medicincentrum, Kardiologiska kliniken US.
    Janzon, Magnus
    Linköpings universitet, Institutionen för medicin och hälsa, Avdelningen för kardiovaskulär medicin. Linköpings universitet, Medicinska fakulteten. Region Östergötland, Hjärt- och Medicincentrum, Kardiologiska kliniken US.
    Engvall, Jan
    Linköpings universitet, Institutionen för medicin och hälsa, Avdelningen för kardiovaskulär medicin. Linköpings universitet, Medicinska fakulteten. Region Östergötland, Hjärt- och Medicincentrum, Fysiologiska kliniken US.
    Persson, Anders
    Linköpings universitet, Centrum för medicinsk bildvetenskap och visualisering, CMIV. Linköpings universitet, Institutionen för medicin och hälsa, Avdelningen för radiologiska vetenskaper. Linköpings universitet, Medicinska fakulteten. Region Östergötland, Diagnostikcentrum, Röntgenkliniken i Linköping.
    Software-based on-site estimation of fractional flow reserve using standard coronary CT angiography data.2016Ingår i: Acta Radiologica, ISSN 0284-1851, E-ISSN 1600-0455, Vol. 57, nr 10, s. 1186-1192Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    BACKGROUND: The significance of a coronary stenosis can be determined by measuring the fractional flow reserve (FFR) during invasive coronary angiography. Recently, methods have been developed which claim to be able to estimate FFR using image data from standard coronary computed tomography angiography (CCTA) exams.

    PURPOSE: To evaluate the accuracy of non-invasively computed fractional flow reserve (cFFR) from CCTA.

    MATERIAL AND METHODS: A total of 23 vessels in 21 patients who had undergone both CCTA and invasive angiography with FFR measurement were evaluated using a cFFR software prototype. The cFFR results were compared to the invasively obtained FFR values. Correlation was calculated using Spearman's rank correlation, and agreement using intraclass correlation coefficient (ICC). Sensitivity, specificity, accuracy, negative predictive value, and positive predictive value for significant stenosis (defined as both FFR ≤0.80 and FFR ≤0.75) were calculated.

    RESULTS: The mean cFFR value for the whole group was 0.81 and the corresponding mean invFFR value was 0.84. The cFFR sensitivity for significant stenosis (FFR ≤0.80/0.75) on a per-lesion basis was 0.83/0.80, specificity was 0.76/0.89, and accuracy 0.78/0.87. The positive predictive value was 0.56/0.67 and the negative predictive value was 0.93/0.94. The Spearman rank correlation coefficient was ρ = 0.77 (P < 0.001) and ICC = 0.73 (P < 0.001).

    CONCLUSION: This particular CCTA-based cFFR software prototype allows for a rapid, non-invasive on-site evaluation of cFFR. The results are encouraging and cFFR may in the future be of help in the triage to invasive coronary angiography.

  • 7.
    Engvall, Jan
    et al.
    Linköpings universitet, Institutionen för medicin och hälsa, Klinisk fysiologi. Linköpings universitet, Hälsouniversitetet. Östergötlands Läns Landsting, Hjärt- och Medicincentrum, Fysiologiska kliniken US.
    Gjerde, Marcus
    Linköpings universitet, Institutionen för medicin och hälsa, Kardiologi. Linköpings universitet, Hälsouniversitetet. Östergötlands Läns Landsting, Hjärt- och Medicincentrum, Kardiologiska kliniken US.
    de Geer, Jakob
    Linköpings universitet, Hälsouniversitetet. Linköpings universitet, Institutionen för medicin och hälsa, Medicinsk radiologi. Östergötlands Läns Landsting.
    Olsson, E.
    Östergötlands Läns Landsting.
    Quick, Petter
    Linköpings universitet, Centrum för medicinsk bildvetenskap och visualisering, CMIV. Linköpings universitet, Institutionen för medicin och hälsa, Medicinsk radiologi. Linköpings universitet, Hälsouniversitetet. Östergötlands Läns Landsting, Diagnostikcentrum, Röntgenkliniken i Linköping.
    Persson, A.
    Östergötlands Läns Landsting. Linköpings universitet, Institutionen för medicin och hälsa, Medicinsk radiologi. Linköpings universitet, Centrum för medicinsk bildvetenskap och visualisering, CMIV. Linköpings universitet, Hälsouniversitetet.
    Adenosine stress myocardial perfusion detected with CT compared with attenuation-corrected SPECT2011Ingår i: EUROPEAN HEART JOURNAL SUPPLEMENTS, Oxford University Press , 2011, Vol. 13, nr A, s. A31-A31Konferensbidrag (Refereegranskat)
    Abstract [en]

    Purpose: To asses adenosine stress myocardial perfusion by cardiac CT and compare with simultaneously performed attenuation corrected SPECT.

    Methods: 11 patients, 9 men and 2 women >2months post primary PCI, with manifest myocardial damage and remaining stenoses in the coronary circulation, were studied with myocardial perfusion CT under vasodilatory stress. The investigation started with a topogram followed by a testbolus of iodine whereafter the coronary artery study was performed in sequence mode. Adenosine was then infused for at least five minutes at the standard rate of 140ug/kg/min. After three minutes, 6 MBq/kg of 99mTc-tetrofosmin was injected immediately followed by 80ml iodine contrast. The wash-in of iodine was monitored by CT scanning of a 7cm long cardiac volume segment every other second for 22s. One hour after the CT scan, myocardial SPECT was performed. Scanning required the patients to tolerate breath holding for 22s, have a heart rate <80/min and body weight <85kg, and their kidney function should allow 140ml 370mg iodine contrast to be given.

    Results: All 11 patients tolerated the full adenosine infusion and scanning was successful. One patient could not be analyzed due to noisy images. In two patients, the limited scanning volume did not cover the entire base of the heart. Three patients had no defect on SPECT. Patients with a defect had on average myocardial blood flow 80ml/100ml tissue/min in the defect area and 142ml in the segments with the highest perfusion, while patients without defect had 98 and 141ml, respectively.

    Conclusion: Peak myocardial perfusion may be determined with CT under adenosine stress and compared with attenuation corrected SPECT. Initial experience shows that the method is sensitive to timing of bolus, to noisy images and results may diverge from those obtained with SPECT.

  • 8.
    Eriksson, Per
    et al.
    Linköpings universitet, Institutionen för medicin och hälsa, Internmedicin. Linköpings universitet, Hälsouniversitetet. Östergötlands Läns Landsting, Medicincentrum, Njurmedicinska kliniken US.
    Mohammed, Ahmed Abdulilah
    Linköpings universitet, Institutionen för medicin och hälsa, Medicinsk radiologi. Linköpings universitet, Hälsouniversitetet. Östergötlands Läns Landsting, Bildmedicinskt centrum, Röntgenkliniken i Linköping.
    De Geer, Jakob
    Linköpings universitet, Institutionen för medicin och hälsa, Medicinsk radiologi. Linköpings universitet, Hälsouniversitetet. Östergötlands Läns Landsting, Bildmedicinskt centrum, Röntgenkliniken i Linköping. Linköpings universitet, Centrum för medicinsk bildvetenskap och visualisering, CMIV.
    Kihlberg, Johan
    Linköpings universitet, Centrum för medicinsk bildvetenskap och visualisering, CMIV. Linköpings universitet, Institutionen för medicin och hälsa, Medicinsk radiologi. Linköpings universitet, Hälsouniversitetet. Östergötlands Läns Landsting, Bildmedicinskt centrum, Röntgenkliniken i Linköping.
    Persson, Anders
    Linköpings universitet, Centrum för medicinsk bildvetenskap och visualisering, CMIV. Linköpings universitet, Institutionen för medicin och hälsa, Medicinsk radiologi. Linköpings universitet, Hälsouniversitetet. Östergötlands Läns Landsting, Bildmedicinskt centrum, Röntgenkliniken i Linköping.
    Granerus, Göran
    Linköpings universitet, Centrum för medicinsk bildvetenskap och visualisering, CMIV. Linköpings universitet, Institutionen för medicin och hälsa, Klinisk fysiologi. Linköpings universitet, Hälsouniversitetet. Östergötlands Läns Landsting, Hjärtcentrum, Fysiologiska kliniken.
    Nyström, Fredrik
    Linköpings universitet, Institutionen för medicin och hälsa, Internmedicin. Linköpings universitet, Hälsouniversitetet.
    Smedby, Örjan
    Linköpings universitet, Centrum för medicinsk bildvetenskap och visualisering, CMIV. Linköpings universitet, Institutionen för medicin och hälsa, Medicinsk radiologi. Linköpings universitet, Hälsouniversitetet. Östergötlands Läns Landsting, Bildmedicinskt centrum, Röntgenkliniken i Linköping.
    Non-invasive investigations of potential renal artery stenosis in renal insufficiency2010Ingår i: Nephrology, Dialysis and Transplantation, ISSN 0931-0509, E-ISSN 1460-2385, Vol. 25, nr 11, s. 3607-3614Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Background. The diagnostic value of non-invasive methods for diagnosing renal artery stenosis in patients with renal insufficiency is incompletely known.

    Methods. Forty-seven consecutive patients with moderately impaired renal function and a clinical suspicion of renal artery stenosis were investigated with computed tomography angiography (CTA), gadolinium-enhanced magnetic resonance angiography (MRA), contrast-enhanced Doppler ultrasound and captopril renography. The primary reference standard was stenosis reducing the vessel diameter by at least 50% on CTA, and an alternative reference standard (‘morphological and functional stenosis’) was defined as at least 50% diameter reduction on CTA or MRA, combined with a positive finding from ultrasound or captopril renography.

    Results. The frequency of positive findings, calculated on the basis of individual patients, was 70% for CTA, 60% for MRA, 53% for ultrasound and 30% for captopril renography. Counting kidneys rather than patients, corresponding frequencies were 53%, 41%, 29% and 15%, respectively. In relation to the CTA standard, the sensitivity (and specificity) at the patient level was 0.81 (0.79) for MRA, 0.70 (0.89) for ultrasound and 0.42 (1.00) for captopril renography, and at the kidney level 0.76 (0.82), 0.53 (0.81) and 0.30 (0.86), respectively. Relative to the alternative reference standard, corresponding values at the patient level were 1.00 (0.62) for CTA, 0.90 (0.69) for MRA, 0.91 (1.00) for ultrasound and 0.67 (1.00) for captopril renography, and at the kidney level 0.96 (0.76), 0.85 (0.79), 0.71 (0.97) and 0.50 (0.97), respectively.

    Conclusions. CTA and MRA are superior to ultrasound and captopril renography at diagnosing morphological stenosis, but ultrasound may be useful as a screening method and captopril renography for verifying renin-dependent hypertension.

  • 9.
    Kihlberg, Johan
    et al.
    Linköpings universitet, Centrum för medicinsk bildvetenskap och visualisering, CMIV. Linköpings universitet, Institutionen för medicin och hälsa, Medicinsk radiologi. Östergötlands Läns Landsting, Diagnostikcentrum, Röntgenkliniken i Linköping. Linköpings universitet, Hälsouniversitetet.
    Kalra, Mannudeep
    Massachusetts General Hospital, Boston, USA.
    Dahlström, Nils
    Linköpings universitet, Centrum för medicinsk bildvetenskap och visualisering, CMIV. Linköpings universitet, Institutionen för medicin och hälsa, Medicinsk radiologi. Östergötlands Läns Landsting, Diagnostikcentrum, Röntgenkliniken i Linköping. Linköpings universitet, Hälsouniversitetet.
    De Geer, Jakob
    Linköpings universitet, Centrum för medicinsk bildvetenskap och visualisering, CMIV. Linköpings universitet, Institutionen för medicin och hälsa, Medicinsk radiologi. Östergötlands Läns Landsting, Diagnostikcentrum, Röntgenkliniken i Linköping. Linköpings universitet, Hälsouniversitetet.
    Rönn, Martin
    ContextVision, Linköping.
    Persson, Anders
    Linköpings universitet, Centrum för medicinsk bildvetenskap och visualisering, CMIV. Linköpings universitet, Institutionen för medicin och hälsa, Medicinsk radiologi. Östergötlands Läns Landsting, Diagnostikcentrum, Röntgenkliniken i Linköping. Linköpings universitet, Hälsouniversitetet.
    Olofsson, Fredrik
    ContextVision, Linköping.
    Bäck, Anni
    ContextVision, Linköping.
    Applying 2D and 3D Postprocessing Algorithms to MR Images: Does Image Quality Improve? Can MR Imaging Duration Be Reduced?2010Ingår i: In Proceedings of RSNA 2010, SSM22, 2010Konferensbidrag (Refereegranskat)
  • 10.
    Smedby, Örjan
    et al.
    Linköpings universitet, Centrum för medicinsk bildvetenskap och visualisering, CMIV. Linköpings universitet, Institutionen för medicin och hälsa, Avdelningen för radiologiska vetenskaper. Linköpings universitet, Hälsouniversitetet. Östergötlands Läns Landsting, Diagnostikcentrum, Röntgenkliniken i Linköping.
    Fredrikson, Mats
    Linköpings universitet, Institutionen för klinisk och experimentell medicin, Yrkes- och miljömedicin. Linköpings universitet, Hälsouniversitetet.
    de Geer, Jakob
    Linköpings universitet, Institutionen för medicin och hälsa, Medicinsk radiologi. Linköpings universitet, Hälsouniversitetet.
    Borgen, L
    Drammen Hospital, Norway .
    Sandborg, Michael
    Linköpings universitet, Institutionen för medicin och hälsa, Medicinsk radiofysik. Linköpings universitet, Hälsouniversitetet. Östergötlands Läns Landsting, Centrum för kirurgi, ortopedi och cancervård, Radiofysikavdelningen US.
    Quantifying the potential for dose reduction with visual grading regression2013Ingår i: British Journal of Radiology, ISSN 0007-1285, E-ISSN 1748-880X, Vol. 86, nr 1021Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Objectives To propose a method to study the effect of exposure settings on image quality and to estimate the potential for dose reduction when introducing dose-reducing measures.

    Methods Using the framework of visual grading regression (VGR), a log(mAs) term is included in the ordinal logistic regression equation, so that the effect of reducing the dose can be quantitatively related to the effect of adding post-processing. In the ordinal logistic regression, patient and observer identity are treated as random effects using generalised linear latent and mixed models. The potential dose reduction is then estimated from the regression coefficients. The method was applied in a single-image study of coronary CT angiography (CTA) to evaluate two-dimensional (2D) adaptive filters, and in an image-pair study of abdominal CT to evaluate 2D and three-dimensional (3D) adaptive filters.

    Results For five image quality criteria in coronary CTA, dose reductions of 16–26% were predicted when adding 2D filtering. Using five image quality criteria for abdominal CT, it was estimated that 2D filtering permits doses were reduced by 32–41%, and 3D filtering by 42–51%.

    Conclusions VGR including a log(mAs) term can be used for predictions of potential dose reduction that may be useful for guiding researchers in designing subsequent studies evaluating diagnostic value. With appropriate statistical analysis, it is possible to obtain direct numerical estimates of the dose-reducing potential of novel acquisition, reconstruction or post-processing techniques.

  • 11.
    Smedby, Örjan
    et al.
    Linköpings universitet, Institutionen för medicin och hälsa, Medicinsk radiologi. Linköpings universitet, Hälsouniversitetet. Östergötlands Läns Landsting, Diagnostikcentrum, Röntgenkliniken i Linköping. Linköpings universitet, Centrum för medicinsk bildvetenskap och visualisering, CMIV.
    Fredrikson, Mats
    Linköpings universitet, Institutionen för klinisk och experimentell medicin, Yrkes- och miljömedicin. Linköpings universitet, Hälsouniversitetet.
    de Geer, Jakob
    Linköpings universitet, Institutionen för medicin och hälsa, Medicinsk radiologi. Linköpings universitet, Hälsouniversitetet.
    Sandborg, Michael
    Linköpings universitet, Institutionen för medicin och hälsa, Medicinsk radiofysik. Linköpings universitet, Hälsouniversitetet. Östergötlands Läns Landsting, Centrum för kirurgi, ortopedi och cancervård, Radiofysikavdelningen US. Linköpings universitet, Centrum för medicinsk bildvetenskap och visualisering, CMIV.
    Quantifying effects of post-processing with visual grading regression2012Ingår i: Medical Imaging 2012: Image Perception, Observer Performance, and Technology Assessment / [ed] Craig K. Abbey; Claudia R. Mello-Thoms, SPIE - International Society for Optical Engineering, 2012, Vol. 8318, s. Art. no. 83181N-Konferensbidrag (Refereegranskat)
    Abstract [en]

    For optimization and evaluation of image quality, one can use visual grading experiments, where observers rate some aspect of image quality on an ordinal scale. To take into account the ordinal character of the data, ordinal logistic regression is used in the statistical analysis, an approach known as visual grading regression (VGR). In the VGR model one may include factors such as imaging parameters and post-processing procedures, in addition to patient and observer identity. In a single-image study, 9 radiologists graded 24 cardiac CTA images acquired with ECG-modulated tube current using standard settings (310 mAs), reduced dose (62 mAs) and reduced dose after post-processing. Image quality was assessed using visual grading with five criteria, each with a five-level ordinal scale from 1 (best) to 5 (worst). The VGR model included one term estimating the dose effect (log of mAs setting) and one term estimating the effect of postprocessing. The model predicted that 115 mAs would be required to reach an 80% probability of a score of 1 or 2 for visually sharp reproduction of the heart without the post-processing filter. With the post-processing filter, the corresponding figure would be 86 mAs. Thus, applying the post-processing corresponded to a dose reduction of 25%. For other criteria, the dose-reduction was estimated to 16-26%. Using VGR, it is thus possible to quantify the potential for dose-reduction of post-processing filters.

  • 12.
    Smedby, Örjan
    et al.
    Linköpings universitet, Institutionen för medicin och hälsa, Medicinsk radiologi. Linköpings universitet, Hälsouniversitetet. Östergötlands Läns Landsting, Diagnostikcentrum, Röntgenkliniken i Linköping. Linköpings universitet, Centrum för medicinsk bildvetenskap och visualisering, CMIV.
    Fredrikson, Mats
    Linköpings universitet, Institutionen för klinisk och experimentell medicin, Yrkes- och miljömedicin. Linköpings universitet, Hälsouniversitetet.
    de Geer, Jakob
    Linköpings universitet, Institutionen för medicin och hälsa, Medicinsk radiologi. Linköpings universitet, Hälsouniversitetet.
    Sandborg, Michael
    Linköpings universitet, Institutionen för medicin och hälsa, Medicinsk radiofysik. Linköpings universitet, Hälsouniversitetet. Östergötlands Läns Landsting, Centrum för kirurgi, ortopedi och cancervård, Radiofysikavdelningen US. Linköpings universitet, Centrum för medicinsk bildvetenskap och visualisering, CMIV.
    Visual grading regression with random effects2012Ingår i: MEDICAL IMAGING 2012: IMAGE PERCEPTION, OBSERVER PERFORMANCE, AND TECHNOLOGY ASSESSMENT, SPIE - International Society for Optical Engineering, 2012, Vol. 8318, s. Art. no. 831805-Konferensbidrag (Refereegranskat)
    Abstract [en]

    To analyze visual grading experiments, ordinal logistic regression (here called visual grading regression, VGR) may be used in the statistical analysis. In addition to types of imaging or post-processing, the VGR model may include factors such as patient and observer identity, which should be treated as random effects. Standard software does not allow random factors in ordinal logistic regression, but using Generalized Linear Latent And Mixed Models (GLLAMM) this is possible. In a single-image study, 9 radiologists graded 24 cardiac Computed Tomography Angiography (CTA) images with reduced dose without and after post-processing with a 2D adaptive filter, using five image quality criteria. First, standard ordinal logistic regression was carried out, treating filtering, patient and observer identity as fixed effects. The same analysis was then repeated with GLLAMM, treating filtering as a fixed effect and patient and observer identity as random effects. With both approaches, a significant effect (pless than0.01) of the filtering was found for all five criteria. No dramatic differences in parameter estimates or significance levels were found between the two approaches. It is concluded that random effects can be appropriately handled in VGR using GLLAMM, but no major differences in the results were found in a preliminary evaluation.

  • 13.
    Wang, Chunliang
    et al.
    Linköpings universitet, Institutionen för medicin och hälsa, Medicinsk radiologi. Linköpings universitet, Hälsouniversitetet. Linköpings universitet, Centrum för medicinsk bildvetenskap och visualisering, CMIV.
    Persson, Anders
    Linköpings universitet, Institutionen för medicin och hälsa, Medicinsk radiologi. Linköpings universitet, Hälsouniversitetet. Östergötlands Läns Landsting, Diagnostikcentrum, Röntgenkliniken i Linköping. Linköpings universitet, Centrum för medicinsk bildvetenskap och visualisering, CMIV.
    Engvall, Jan
    Linköpings universitet, Institutionen för medicin och hälsa, Klinisk fysiologi. Linköpings universitet, Hälsouniversitetet. Östergötlands Läns Landsting, Hjärt- och Medicincentrum, Fysiologiska kliniken US.
    de Geer, Jakob
    Linköpings universitet, Hälsouniversitetet. Linköpings universitet, Institutionen för medicin och hälsa, Medicinsk radiologi.
    Björkholm, Anders
    Östergötlands Läns Landsting, Diagnostikcentrum, Röntgenkliniken i Linköping.
    Czekierda, Waldemar
    Östergötlands Läns Landsting, Diagnostikcentrum, Röntgenkliniken i Linköping.
    Fransson, Sven Göran
    Linköpings universitet, Institutionen för medicin och hälsa, Medicinsk radiologi. Linköpings universitet, Hälsouniversitetet.
    Smedby, Örjan
    Linköpings universitet, Institutionen för medicin och hälsa, Medicinsk radiologi. Linköpings universitet, Hälsouniversitetet. Östergötlands Läns Landsting, Bildmedicinskt centrum, Röntgenkliniken i Linköping.
    Can segmented 3D images be used for stenosis evaluation in coronary CT angiography?2012Ingår i: Acta Radiologica, ISSN 0284-1851, E-ISSN 1600-0455, Vol. 53, nr 8, s. 845-851Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Purpose: To retrospectively evaluate the diagnostic accuracy of coronary CT angiography (CCTA) using segmented 3D data for the detection of significant stenoses with catheter angiography (CA) as the reference standard.

    Method: CCTA data sets from 30 patients were acquired with a 64-slice dual source CT scanner and segmented by an independent observer using the region growing (RG) method and the “virtual contrast injection” (VC) method. For every examination, each of the three types of images was  then reviewed by one of three reviewers in a blinded fashion for the presence of stenoses with diameter reduction of 50% or more. For the original series, the reviewer was allowed to use all the 2D or 3D visualization tools available (mixed method). For the segmented results (from RG and VC), the reviewer only used the 3D maximum intensity projection. Evaluation results were compared with CA for each artery.

    Results: Overall, 34 arteries with significant stenosis were identified by CA. The percentage of evaluable arteries, accuracy and negative predictive value (NPV) for detecting stenosis were, respectively, 86%, 74% and 93% for the mixed method, 83%, 71% and 92% for VC, and 64%, 56% and 93% for RG. Accuracy was significantly lower for the RG method than for the other two methods (p<0.01), whereas there was no significant difference in accuracy between the VC method and the mixed method (p = 0.22). Excluding vessels with heavy calcification, all three methods had similar accuracy.

    Conclusion: Diagnostic accuracy when using segmented 3D data was lower than with access to 2D images. However, the high NPV of the 3D methods suggests a potential of using them as an initial step, with access to 2D reviewing techniques for suspected lesions and cases with heavy calcification. The VC method, which generates more evaluable arteries and has higher accuracy, seems more promising for this purpose than the RG method.

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