liu.seSearch for publications in DiVA
Change search
Link to record
Permanent link

Direct link
BETA
Quick, Petter
Publications (10 of 12) Show all publications
Kalra, M. K., Woisetschläger, M., Dahlström, N., Singh, S., Digumarthy, S., Do, S., . . . Persson, A. (2013). Sinogram-Affirmed Iterative Reconstruction of Low-Dose Chest CT: Effect on Image Quality and Radiation Dose. American Journal of Roentgenology, 201(2), W235-W244
Open this publication in new window or tab >>Sinogram-Affirmed Iterative Reconstruction of Low-Dose Chest CT: Effect on Image Quality and Radiation Dose
Show others...
2013 (English)In: American Journal of Roentgenology, ISSN 0361-803X, E-ISSN 1546-3141, Vol. 201, no 2, p. W235-W244Article in journal (Refereed) Published
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.

Place, publisher, year, edition, pages
American Roentgen Ray Society (ARRS), 2013
Keywords
iterative reconstruction, low-dose chest CT, radiation dose reduction
National Category
Medical and Health Sciences
Identifiers
urn:nbn:se:liu:diva-96707 (URN)10.2214/AJR.12.9569 (DOI)000322225400008 ()
Note

Funding Agencies|Siemens Healthcare||

Available from: 2013-08-23 Created: 2013-08-23 Last updated: 2017-12-06Bibliographically approved
Kalra, M., Quick, P., Singh, S., Sandborg, M. & Persson, A. (2013). Whole spine CT for evaluation of scoliosis in children: feasibility of sub-milliSievert scanning protocol. Acta Radiologica, 54(2), 226-230
Open this publication in new window or tab >>Whole spine CT for evaluation of scoliosis in children: feasibility of sub-milliSievert scanning protocol
Show others...
2013 (English)In: Acta Radiologica, ISSN 0284-1851, E-ISSN 1600-0455, Vol. 54, no 2, p. 226-230Article in journal (Refereed) Published
Abstract [en]

Background Optimization of CT radiation dose is important for children due to their higher risk of radiation-induced adverse effects. Anatomical structures with high inherent contrast, such as bones can be imaged at very low radiation doses by optimizing scan parameters.                    

Purpose To assess feasibility of sub-milliSievert whole spine CT scanning protocol for evaluation of scoliosis in children.                    

Material and Methods With approval of the ethical board, we performed whole spine CT for evaluation of scoliosis in 22 children (age range, 3–18 years; mean age, 13 years; 13 girls, 9 boys) on a 128-slice dual source multidetector-row CT scanner. Lowest possible quality reference mAs value (image quality factor for xy-z automatic exposure control or xyz-AEC, CARE Dose 4D) was selected on a per patient basis. Remaining parameters were held constant at 3.0:1 pitch, 128 × 0.6 mm detector collimation, 115.2 mm table feed per gantry rotation, 100 kVp, and 1 and 3 mm reconstructed sections. Average mAs, projected estimated dose savings with AEC, computed tomography dose index volume (CTDI vol), and dose length product (DLP) were recorded. Artifacts were graded on a four-point scale (1, no artifacts; 4, severe artifacts). Ability to identify vertebral and pedicular contours, and measure pedicular width and degree of vertebral rotation was graded on a three-point scale (1, unacceptable; 3, excellent).       

Results All CT examinations were deemed as reliable for identifying vertebral and pedicular contours as well as for measuring pedicular width (5.9 ± 1.6 mm) and degree of vertebral rotation (28.7 ± 23.4°). Mean objective image noise and signal to noise ratio (SNR) were 57.5 ± 21.5 and 4.7 ± 2.3, respectively. With a mean quality reference mAs of 13, the scanner employed an average actual effective mAs of 10 ± 3.8 (range, 6–18 mAs) with an estimated radiation dose saving of 43.5 ± 16.3% with xyz-AEC compared with fixed mAs. The mean CTDI, DLP, and estimated effective doses were 0.4 ± 0.1 mGy (0.2–0.7 mGy), 21 ± 10 mGy.cm (8–41 mGy.cm), and 0.3 ± 0.1 mSv (0.12–0.64 mSv), respectively.                    

Conclusion Radiation dose for whole spine CT for evaluation of scoliosis in children can be minimized to less than one-third of a milliSievert while maintaining diagnostic image quality.

Place, publisher, year, edition, pages
Sage Publications, 2013
Keywords
CT, scoliosis, radiation dose, automatic exposure control
National Category
Medical and Health Sciences
Identifiers
urn:nbn:se:liu:diva-91219 (URN)10.1258/ar.2012.110625 (DOI)000322321400015 ()23138023 (PubMedID)
Available from: 2013-04-22 Created: 2013-04-17 Last updated: 2017-12-06
Dahlström, N., Dahlqvist Leinhard, O., Kihlberg, J., Quick, P., Forsgren, M., Lundberg, P. & Persson, A. (2012). Dual-Energy CT Detects Standard-Dose Gd-EOB-DTPA in the Hepatobiliary and Renal Systems of Patients Having Undergone Liver MRI. In: : . Paper presented at RSNA 2012, November 25-30, 2012, Chicago, USA.
Open this publication in new window or tab >>Dual-Energy CT Detects Standard-Dose Gd-EOB-DTPA in the Hepatobiliary and Renal Systems of Patients Having Undergone Liver MRI
Show others...
2012 (English)Conference paper, Oral presentation with published abstract (Other academic)
National Category
Medical and Health Sciences
Identifiers
urn:nbn:se:liu:diva-90382 (URN)
Conference
RSNA 2012, November 25-30, 2012, Chicago, USA
Available from: 2013-03-25 Created: 2013-03-25 Last updated: 2019-06-14
Kalra, M. K., Woisetschläger, M., Dahlström, N., Sing, S., Lindblom, M., Choy, G., . . . Persson, A. (2012). Radiation Dose Reduction with Sinogram Affirmed Iterative Reconstruction Technique for abdominal Computer Tomography. Journal of Computer Assisted Tomography, 36(3), 339-346
Open this publication in new window or tab >>Radiation Dose Reduction with Sinogram Affirmed Iterative Reconstruction Technique for abdominal Computer Tomography
Show others...
2012 (English)In: Journal of Computer Assisted Tomography, ISSN 0363-8715, Vol. 36, no 3, p. 339-346Article in journal (Refereed) Published
Abstract [en]

Purpose: The objective of this study was to assess the effect of Sinogram Affirmed Iterative Reconstruction (SAFIRE) and filtered back-projection (FBP) techniques on abdominal computed tomography (CT) performed with 50% and 75% radiation dose reductions.

Methods: Twenty-four patients (mean age, 64 ± 14 years; male-female ratio, 10:14) gave informed consent for an institutional review board–approved prospective study involving acquisition of additional research images through the abdomen on 128-slice multi–detector-row CT (SOMATOM Definition Flash) at quality reference mAs of 100 (50% lower dose) and 50 (75% lower dose) over a scan length of 10 cm using combined modulation (CARE Dose 4D). Standard-of-care abdominal CT was performed at 200 quality reference mAs, with remaining parameters held constant. The 50- and 100-mAs data sets were reconstructed with FBP and at 4 SAFIRE settings (S1, S2, S3, S4). Higher number of SAFIRE settings denotes increased strength of the algorithm resulting in lower image noise. Two abdominal radiologists independently compared the FBP and SAFIRE images for lesion number, location, size and conspicuity, and visibility of small structures, image noise, and diagnostic confidence. Objective noise and Hounsfield units (HU) were measured in the liver and the descending aorta.

Results: All 43 lesions were detected on both FBP and SAFIRE images. Minor blocky, pixelated appearance of 50% and 75% reduced dose images was noted at S3 and S4 SAFIRE but not at S1 and S2 settings. Subjective noise was suboptimal in both 50% and 75% lower-dose FBP images but was deemed acceptable on all SAFIRE settings. Sinogram Affirmed Iterative Reconstruction images were deemed acceptable in all patients at 50% lower dose and in 22 of 24 patients at 75% lower dose. As compared with 75% reduced dose FBP, objective noise was lower by 22.8% (22.9/29.7), 35% (19.3/29.7), 44.3% (16.7/29.3), and 54.8% (13.4/29.7) on S1 to S4 settings, respectively (P < 0.001).

Conclusions: Sinogram Affirmed Iterative Reconstruction–enabled reconstruction provides abdominal CT images without loss in diagnostic value at 50% reduced dose and in some patients also at 75% reduced dose.

Place, publisher, year, edition, pages
USA: Lippincott Williams & Wilkins, 2012
National Category
Medical and Health Sciences
Identifiers
urn:nbn:se:liu:diva-75846 (URN)10.1097/RCT.0b013e31825586c0 (DOI)000304201200013 ()
Available from: 2012-03-12 Created: 2012-03-12 Last updated: 2017-03-07
Engvall, J., Gjerde, M., de Geer, J., Olsson, E., Quick, P. & Persson, A. (2011). Adenosine stress myocardial perfusion detected with CT compared with attenuation-corrected SPECT. In: EUROPEAN HEART JOURNAL SUPPLEMENTS: . Paper presented at 10th International Conference of Non-Invasive Cardiovascular Imaging (pp. A31-A31). Oxford University Press, 13(A)
Open this publication in new window or tab >>Adenosine stress myocardial perfusion detected with CT compared with attenuation-corrected SPECT
Show others...
2011 (English)In: EUROPEAN HEART JOURNAL SUPPLEMENTS, Oxford University Press , 2011, Vol. 13, no A, p. A31-A31Conference paper, Poster (with or without abstract) (Refereed)
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.

Place, publisher, year, edition, pages
Oxford University Press, 2011
Series
EUROPEAN HEART JOURNAL SUPPLEMENTS, ISSN 1520-765X ; A
National Category
Engineering and Technology
Identifiers
urn:nbn:se:liu:diva-69922 (URN)000291748800089 ()
Conference
10th International Conference of Non-Invasive Cardiovascular Imaging
Available from: 2011-08-09 Created: 2011-08-08 Last updated: 2014-05-08
Dahlström, N., Quick, P., Kalra, M. K. & Persson, A. (2011). Dual-Energy CT: Uncovering and Troubleshooting New Pitfalls and Artefacts. Educational Exhibit. In: : . Paper presented at RSNA 2011, Chicago.
Open this publication in new window or tab >>Dual-Energy CT: Uncovering and Troubleshooting New Pitfalls and Artefacts. Educational Exhibit
2011 (English)Conference paper, Published paper (Refereed)
National Category
Medical and Health Sciences
Identifiers
urn:nbn:se:liu:diva-75774 (URN)
Conference
RSNA 2011, Chicago
Available from: 2012-03-09 Created: 2012-03-09 Last updated: 2014-05-08
Kalra, M. K., Persson, A., Quick, P., Digumarthy, S. R., Sandborg, M. & Singh, S. (2010). Can image space iterative reconstruction technique allow 60% dose reduction for thoracic CT? Results for a randomised prospective pilot study. In: SSQ03-06: . Paper presented at RSNA 2010.
Open this publication in new window or tab >>Can image space iterative reconstruction technique allow 60% dose reduction for thoracic CT? Results for a randomised prospective pilot study
Show others...
2010 (English)In: SSQ03-06, 2010Conference paper, Oral presentation with published abstract (Other academic)
National Category
Medical and Health Sciences
Identifiers
urn:nbn:se:liu:diva-62790 (URN)
Conference
RSNA 2010
Available from: 2010-12-03 Created: 2010-12-03 Last updated: 2014-05-08
Kalra, M. K., Persson, A., Quick, P. & Sandborg, M. (2010). Combining high pitch, low kV and 4D automatic exposure controll technique for reducing CT radiation dose for mapping of pulmonary venous anatomy. In: SSJ05-05: . Paper presented at RSNA 2010, Chicago, USA.
Open this publication in new window or tab >>Combining high pitch, low kV and 4D automatic exposure controll technique for reducing CT radiation dose for mapping of pulmonary venous anatomy
2010 (English)In: SSJ05-05, 2010Conference paper, Published paper (Other academic)
National Category
Radiology, Nuclear Medicine and Medical Imaging
Identifiers
urn:nbn:se:liu:diva-62788 (URN)
Conference
RSNA 2010, Chicago, USA
Available from: 2010-12-03 Created: 2010-12-03 Last updated: 2014-05-08
Kalra, M., Persson, A., Quick, P. & Sandborg, M. (2010). Combining low kVp, lowest tube current, high pitch and fast table speed for minimizing radiation dose for whole body CT imaging of children with scoliosis. In: SSK14-08. Paper presented at RSNA 2010.
Open this publication in new window or tab >>Combining low kVp, lowest tube current, high pitch and fast table speed for minimizing radiation dose for whole body CT imaging of children with scoliosis
2010 (English)In: SSK14-08, 2010Conference paper, Published paper (Other academic)
National Category
Radiology, Nuclear Medicine and Medical Imaging
Identifiers
urn:nbn:se:liu:diva-62791 (URN)
Conference
RSNA 2010
Available from: 2010-12-03 Created: 2010-12-03 Last updated: 2013-10-21
Kalra, M., Persson, A., Quick, P., Digumarthy, S. R., Pien, H. H. & Singh, S. (2010). Iterative Reconstruction Techniques: The Be-All and End-All for CT Dose Reduction? Pictorial Synopsis of Different Vendor Techniques. In: In Proceedings of RSNA 2010, LL-PHE 4076. Paper presented at RSNA, Chicago, USA 2010.
Open this publication in new window or tab >>Iterative Reconstruction Techniques: The Be-All and End-All for CT Dose Reduction? Pictorial Synopsis of Different Vendor Techniques
Show others...
2010 (English)In: In Proceedings of RSNA 2010, LL-PHE 4076, 2010Conference paper, Published paper (Refereed)
Abstract [en]

Recently introduced IRT for clinical use allow dose reduction for adult and pediatric CT while maintaining or even enhancing image quality compared to filtered back projection based reconstruction. Specific adjustments of scanning protocols and fine-tuning of iterative settings are necessary to ensure optimum usage with understanding of its potential and disadvantages. This educational exhibit focuses on clinical illustrations to simplify application of IRT for reducing CT radiation dose

National Category
Radiology, Nuclear Medicine and Medical Imaging
Identifiers
urn:nbn:se:liu:diva-64336 (URN)
Conference
RSNA, Chicago, USA 2010
Available from: 2011-01-19 Created: 2011-01-19 Last updated: 2013-10-21
Organisations

Search in DiVA

Show all publications