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  • 1.
    de Geer, Jakob
    et al.
    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.
    Coenen, Adriaan
    Erasmus MC, Netherlands.
    Kim, Young-Hak
    Univ Ulsan, South Korea.
    Kruk, Mariusz
    Inst Cardiol, Poland; Inst Cardiol, Poland.
    Tesche, Christian
    Med Univ South Carolina, SC 29425 USA.
    Schoepf, U. Joseph
    Med Univ South Carolina, SC 29425 USA.
    Kepka, Cezary
    Inst Cardiol, Poland; Inst Cardiol, Poland.
    Yang, Dong Hyun
    Univ Ulsan, South Korea.
    Nieman, Koen
    Erasmus MC, Netherlands; Stanford Univ, CA 94305 USA; Stanford Univ, CA 94305 USA.
    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.
    Effect of Tube Voltage on Diagnostic Performance of Fractional Flow Reserve Derived From Coronary CT Angiography With Machine Learning: Results From the MACHINE Registry2019Inngår i: American Journal of Roentgenology, ISSN 0361-803X, E-ISSN 1546-3141, Vol. 213, nr 2, s. 325-331Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    OBJECTIVE. Coronary CT angiography (CCTA)-based methods allow noninvasive estimation of fractional flow reserve (cFFR), recently through use of a machine learning (ML) algorithm (cFFR(ML)). However, attenuation values vary according to the tube voltage used, and it has not been shown whether this significantly affects the diagnostic performance of cFFR and cFFR(ML). Therefore, the purpose of this study is to retrospectively evaluate the effect of tube voltage on the diagnostic performance of cFFR(ML). MATERIALS AND METHODS. A total of 525 coronary vessels in 351 patients identified in the MACHINE consortium registry were evaluated in terms of invasively measured FFR and cFFR(ML). CCTA examinations were performed with a tube voltage of 80, 100, or 120 kVp. For each tube voltage value, correlation (assessed by Spearman rank correlation coefficient), agreement (evaluated by intraclass correlation coefficient and Bland-Altman plot analysis), and diagnostic performance (based on ROC AUC value, sensitivity, specificity, positive predictive value, negative predictive value, and accuracy) of the cFFR(ML) in terms of detection of significant stenosis were calculated. RESULTS. For tube voltages of 80, 100, and 120 kVp, the Spearman correlation coefficient for cFFR(ML) in relation to the invasively measured FFR value was rho = 0.684, rho = 0.622, and rho = 0.669, respectively (p amp;lt; 0.001 for all). The corresponding intraclass correlation coefficient was 0.78, 0.76, and 0.77, respectively (p amp;lt; 0.001 for all). Sensitivity was 100.0%, 73.5%, and 85.0%, and specificity was 76.2%, 79.0%, and 72.8% for tube voltages of 80, 100, and 120 kVp, respectively. The ROC AUC value was 0.90, 0.82, and 0.80 for 80, 100, and 120 kVp, respectively (p amp;lt; 0.001 for all). CONCLUSION. CCTA-derived cFFR(ML) is a robust method, and its performance does not vary significantly between examinations performed using tube voltages of 100 kVp and 120 kVp. However, because of rapid advancements in CT and postprocessing technology, further research is needed.

  • 2.
    Kalra, Mannudeep K.
    et al.
    Division of Thoraic Imaging, Department of Radiology, Massachusetts General Hospital, Boston, USA .
    Woisetschläger, Mischa
    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.
    Dahlström, Nils
    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.
    Singh, Sarabjeet
    Massachusetts General Hospital, Boston, USA .
    Digumarthy, Subbarao
    Massachusetts General Hospital, Boston, USA .
    Do, Synho
    Massachusetts General Hospital, Boston, USA .
    Pien, Homer
    Massachusetts General Hospital, Boston, USA .
    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.
    Schmidt, Bernhard
    Siemens Healthcare, Forchheim, Germany..
    Sedlmair, Martin
    Siemens Healthcare, Forchheim, Germany.
    Shepard, Jo-Anne O.
    Massachusetts General Hospital, Boston, USA .
    Persson, Anders
    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.
    Sinogram-Affirmed Iterative Reconstruction of Low-Dose Chest CT: Effect on Image Quality and Radiation Dose2013Inngår i: American Journal of Roentgenology, ISSN 0361-803X, E-ISSN 1546-3141, Vol. 201, nr 2, s. W235-W244Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    OBJECTIVE. The purpose of this study is to compare sinogram-affirmed iterative reconstruction (SAFIRE) and filtered back projection (FBP) reconstruction of chest CT acquired with 65% radiation dose reduction.

    SUBJECTS AND METHODS. In this prospective study involving 24 patients (11 women and 13 men; mean [+/- SD] age, 66 +/- 10 years), two scan series were acquired using 100 and 40 Quality Reference mAs over a 10-cm scan length in the chest with a 128-MDCT scanner. The 40 Quality Reference mAs CT projection data were reconstructed with FBP and four settings of Safire (S1, S2, S3, and S4). Six image datasets (FBP with 100 and 40 Quality Reference mAs, and S1, S2, S3, S4 with 40 Quality Reference mAs) were displayed on a DICOM-compliant 55-inch 2-megapixel monitor for blinded evaluation by two thoracic radiologists for number and location of lesions, lesion size, lesion margins, visibility of small structures and fissures, and diagnostic confidence. Objective noise and CT values were measured in thoracic aorta for each image series, and the noise power spectrum was assessed. Data were analyzed with analysis of variance and Wilcoxon signed rank tests.

    RESULTS. All 186 lesions were seen on 40 Quality Reference mAs SAFIRE images. Diagnostic confidence on SAFIRE images was higher than that for FBP images. Except for the minor blotchy appearance on SAFIRE settings S3 and S4, no significant artifacts were noted. Objective noise with 40 Quality Reference mAs S1 images (21.1 +/- 6.1 SD of HU) was significantly lower than that for 40 Quality Reference mAs FBP images (28.5 +/- 8.1 SD of HU) (p andlt; 0.001). Noise power spectra were identical for SAFIRE and FBP with progressive noise reduction with higher iteration SAFIRE settings.

    CONCLUSION. Iterative reconstruction (SAFIRE) allows reducing the radiation exposure by approximately 65% without losing diagnostic information in chest CT.

  • 3.
    Kemerink, Martijn
    et al.
    Maastricht University, Netherlands.
    Dierichs, Tom J.
    Maastricht University, Netherlands; Maastricht University, Netherlands.
    Dierichs, Julien
    Maastricht University, Netherlands; Maastricht University, Netherlands.
    Huynen, Hubert
    Maastricht University, Netherlands; Maastricht University, Netherlands.
    Wildberger, Joachim E.
    Maastricht University, Netherlands; Maastricht University, Netherlands.
    van Engelshoven, Jos M. A.
    Maastricht University, Netherlands; Maastricht University, Netherlands.
    Kemerink, Gerrit J.
    Maastricht University, Netherlands; Maastricht University, Netherlands.
    Editorial Material: The Application of X-Rays in Radiology: From Difficult and Dangerous to Simple and Safe in AMERICAN JOURNAL OF ROENTGENOLOGY, vol 198, issue 4, pp 754-7592012Inngår i: American Journal of Roentgenology, ISSN 0361-803X, E-ISSN 1546-3141, Vol. 198, nr 4, s. 754-759Artikkel i tidsskrift (Annet vitenskapelig)
    Abstract [en]

    OBJECTIVE. This article will provide an assessment of the application of x-rays in the early days of radiology, which is an excellent way to come to value the convenience and safety of modern x-ray systems. CONCLUSION. The gas tubes that were originally applied for x-ray production were very unstable because of variations in the tubes vacuum. In an effort to understand some of the problems of these tubes and the high occupational exposure that was indirectly caused by the tubes erratic behavior, we measured x-ray output rates as a function of the gas pressure inside the tube. The pressure range for the optimal production of x-rays, using an original Ruhmkorff inductor as a high-voltage generator, was found to be narrow. With the vacuum changing over time, this might explain the many photographs from the first years of radiology with operators watching their unshielded tube, either with bare eyes or with a fluoroscope, and their own hand as a test object. This practice often led to severe damage of the hands and to many early deaths due to cancer. Today, after a century of technologic development of x-ray tubes and associated equipment, the total average effective dose of workers in radiology can be close to natural background levels.

  • 4.
    Kim, Hae Young
    et al.
    Seoul Natl Univ, South Korea.
    Park, Ji Hoon
    Seoul Natl Univ, South Korea.
    Lee, Sung Soo
    Seoul Natl Univ, South Korea.
    Lee, Woo Joo
    Inha Univ, South Korea.
    Ko, Yousun
    Seoul Natl Univ, South Korea.
    Andersson, Roland
    Linköpings universitet, Institutionen för klinisk och experimentell medicin, Avdelningen för Kirurgi, Ortopedi och Onkologi. Linköpings universitet, Medicinska fakulteten. Jonkoping Cty Council, Futurum Acad Hlth and Care, Linkoping, Sweden.
    Lee, Kyoung Ho
    Seoul Natl Univ, South Korea.
    CT in Differentiating Complicated From Uncomplicated Appendicitis: Presence of Any of 10 CT Features Versus Radiologists Gestalt Assessment2019Inngår i: American Journal of Roentgenology, ISSN 0361-803X, E-ISSN 1546-3141, Vol. 213, nr 5, s. W218-W226Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    OBJECTIVE. The purpose of this study is to propose a sensitive CT criterion (the presence of any of 10 CT features) for complicated appendicitis that could be used in the nonoperative management of appendicitis and to compare the diagnostic performance of this sensitive CT criterion with that of gestalt assessment. MATERIALS AND METHODS. This retrospective study, which was conducted in a tertiary teaching hospital, included 100 patients with suspected appendicitis on CT. Complicated appendicitis, defined as gangrenous or perforated appendicitis, was pathologically or surgically confirmed in 32 patients. Six radiologists independently determined the presence of 10 previously reported CT features of complicated appendicitis (contrast enhancement defect of the appendiceal wall, abscess, extraluminal air, intraluminal air, extraluminal appendicolith, intraluminal appendicolith, moderate-to-severe periappendiceal fat stranding, periappendiceal fluid, ileus, and ascites) and rated the likelihood score for complicated appendicitis using gestalt assessment. The sensitivity and specificity of CT for complicated appendicitis were measured by the presence of any of 10 CT features (the any-of-10-features criterion) and by the radiologists gestalt assessment. Pooled sensitivity and specificity were compared using a generalized linear mixed model. RESULTS. The pooled sensitivity of the presence of any of 10 CT features was higher than that of gestalt assessment (92% vs 64%; difference, 28% [95% CI, 10-46%]; p amp;lt; 0.001), although the pooled specificity was lower (43% vs 76%; difference, -33% [95% CI, -48% to -17%]; p amp;lt; 0.001). CONCLUSION. The pooled sensitivity of the presence of any of 10 CT features was higher than that of gestalt assessment, at the cost of lower specificity. For prudent selection of patients who should receive nonoperative treatment of appendicitis, the any-of-10-features criterion may be used to decrease treatment failure associated with a false-negative diagnosis of complication.

  • 5.
    Ross, Steffen
    et al.
    Linköpings universitet, Centrum för medicinsk bildvetenskap och visualisering, CMIV. Linköpings universitet, Hälsouniversitetet.
    Ebner, Lukas
    University of Bern, Switzerland .
    Flach, Patricia
    University Hospital of Zürich, Switzerland and University of Zurich, Switzerland .
    Brodhage, Rolf
    Roentgen Institut Brunnhof, Bern, Switzerland.
    Bolliger, Stephan A.
    University of Bern, Switzerland .
    Christe, Andreas
    Linköpings universitet, Centrum för medicinsk bildvetenskap och visualisering, CMIV. Linköpings universitet, Hälsouniversitetet.
    Thali, Michael J.
    University of Zurich, Switzerland .
    Postmortem Whole-Body MRI in Traumatic Causes of Death2012Inngår i: American Journal of Roentgenology, ISSN 0361-803X, E-ISSN 1546-3141, Vol. 199, nr 6, s. 1186-1192Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    OBJECTIVE:

    The aim of this study was to determine the sensitivity and specificity of postmortem whole-body MRI for typical injuries resulting from traumatic causes of death.

    MATERIALS AND METHODS:

    Forty cases of accidental death were evaluated with postmortem whole-body MRI. Imaging was conducted according to a standard protocol, and each examination had an average duration of 90 minutes. The imaging findings were correlated with the autopsy findings, which served as the reference standard.

    RESULTS:

    MRI showed the main pathologic process leading to death in 39 of the 40 cases. The sensitivity of postmortem MRI ranged from 100% (pneumothorax) to 40% (fractures of the upper extremities). In general, MRI had a high level of performance for depicting soft-tissue lesions, such as subcutaneous hematoma (e.g., galeal hematoma with a sensitivity 95%). The sensitivity of MRI was remarkably lower for lesions of the upper abdominal organs (liver, 80%; spleen, 50%; pancreas, 60%; kidneys, 66%).

    CONCLUSION:

    Postmortem whole-body MRI had overall good performance for depicting traumatic findings in corpses and therefore may serve an important role as an adjunct to classic autopsy for the forensic examination of cases of traumatic cause of death. However, the reduced sensitivity of postmortem MRI for lacerations of the upper abdominal organs and the observed superimposition of antemortem findings and postmortem findings (e.g., in the pulmonary tissue) in this retrospective study suggest that whole-body postmortem MRI not be recommended as a replacement for classic autopsy.

  • 6.
    Rubesova, Erika
    et al.
    Department of Radiology, Lucile Packard Children's Hospital, Stanford University, Stanford, CA , USA.
    Vance, Chardonnay J
    Schulze Diabetes Institute, Minneapolis, MN. USA.
    Ringertz, Hans G
    Department of Radiology, Lucile Packard Children's Hospital, Stanford University, Stanford, CA , USA.
    Barth, Richard A
    Department of Radiology, Lucile Packard Children's Hospital, Stanford University, Stanford, CA , USA.
    Three-dimensional MRI volumetric measurements of the normal fetal colon2009Inngår i: American Journal of Roentgenology, ISSN 0361-803X, E-ISSN 1546-3141, Vol. 192, nr 3, s. 761-765Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    OBJECTIVE: The use of fetal MRI markedly improves characterization of abdominal congenital anomalies. Accurate prenatal diagnosis of the level and cause of congenital intestinal obstruction is desired for optimal parental counseling and perinatal care. Because accurate diagnosis would be aided by nomograms of colonic volume, this study was conducted to determine normal colonic volumes at different gestational ages. MATERIALS AND METHODS: This retrospective study consisted of a review of 83 fetal MRI examinations performed on fetuses with no gastrointestinal abnormalities. MRI was performed with a 1.5-T system. Axial, sagittal, and coronal T1-weighted fast gradient-refocused echo images were acquired at TR/TE, 165/2.6; flip angle, 90 degrees; matrix size, 384 x 192; slice thickness, 5 mm; field of view, 38 cm(2). Two investigators determined the region of interest in the colon by outlining areas of high signal intensity of meconium slice by slice. They then calculated colonic luminal volume in the regions of interest. Colonic luminal volumes were reported relative to gestational age and abdominal circumference. Normative curves were generated, and interobserver and intraobserver analyses were performed. RESULTS: Seventeen of the 83 fetuses (20%) were excluded because of movement artifacts on the images. Normal colonic luminal volume increased exponentially with gestational age and abdominal circumference. The range of colonic luminal volumes at 20-37 weeks' gestational age was 1.1-65 mL. Variation of volume was greater at advanced gestational age. Interobserver and intraobserver correlation was good. CONCLUSION: This study yielded preliminary volumetric measurements of the normal fetal colon at 20-37 weeks of gestational age that suggest the fetal colon grows exponentially.

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