Jeffrey T Lund

Mayo Clinic - Scottsdale, Scottsdale, Arizona, United States

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Publications (5)11.43 Total impact

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    ABSTRACT: Purpose To determine whether radiation doses during computed tomography (CT) colonography (CTC) can be further reduced while maintaining image quality using model-based iterative reconstruction (MBIR). Methods Twenty patients underwent CTC at a standard dose in supine and prone positions and at a reduced dose in the supine position. All other scan parameters (except noise index) were held constant. Acquisitions were reconstructed using 3 algorithms: filtered back projection (FBP), adaptive statistical iterative reconstruction (ASIR), and MBIR. Noise was assessed quantitatively by comparing the SD in Hounsfield units at 5 standard locations. Qualitative assessment was made by 2 experienced radiologists blinded to technique who subjectively scored image quality, noise, and sharpness (from 0 to 4). Results The standard-dose and reduced-dose CT dose index/dose-length product were 6.7/328 and 2.7 mGy/129 mGy-cm, respectively (60 % reduction). Measured mean noise level increased from the standard to the reduced dose (FBP, from 58.6 to 97.2; ASIR from 35.8 to 60.6; and MBIR from 16.6 to 21.9). MBIR had significantly less noise than ASIR on 2-dimensional images at both standard and reduced doses (P
    No preview · Article · Oct 2014 · Abdominal Imaging
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    ABSTRACT: PURPOSE Reduce CT Colonography (CTC) radiation dose using model based iterative reconstruction (MBIR) while maintaining image quality. METHOD AND MATERIALS After colon prep w/ stool tagging, 20 patients (11M/9F; 40–95 yrs, Ave. BMI=31.6) underwent CTC standard dose (SD) and reduced dose (RD). 2 acquisitions at SD in supine & prone positions: 120 kVp, Auto mA (m/M 30/450), Noise Index (NI)=65, yield ave. dose 4 mSv. Additional single supine acquisition at RD: NI=92, other parameters unchanged, expected 50% reduced radiation dose. All images reconstructed with 3 algorithms: filtered back projection (FBP), adaptive statistical iterative reconstruction (ASIR), MBIR. Image noise quantified using ROI to measure HU standard deviation at 5 locations (liver, kidney, both psoas muscles, aorta) in each patient. Also, images reviewed by 2 experienced radiologists (>500 CTC cases) blinded to scan technique. Observers independently scored image quality and noise at 3 sites (cecum, rectosigmoid, splenic flexure). Image noise was graded on a scale from 0 to 4 (nondiagnostic to no perceptible noise). Image quality was scored from 0 (nondiagnostic) to 4 (high confidence of detecting ≤5 mm lesion). RESULTS Ave. CTDI decreased 60% from 6.7 mGy on SD to 2.7 mGy on RD. As expected, measured average image noise level increased from SD (FBP 58.6, ASIR 35.8, MBIR 16.6) to RD (FBP 97.2, ASIR 60.6, MBIR 21.9); all algorithms improved measured noise levels. Importantly, noise was less on RD MBIR compared to SD ASIR images (p<.01). Images from either SD or RD FBP were noisier than comparable ASIR or MBIR. On 2D SD or LD images, MBIR had less noise than ASIR (p<.0001). Notably, 2D image noise was less on RD MBIR than SD ASIR (p<.0001). Subjective 2D image quality was (FBP 3.9, ASIR 3.95, MBIR 3.96) on SD and (FBP 3.72, ASIR 3.9, MBIR 3.98) on RD. Neither 2D nor 3D image quality was significantly different between SD ASIR and MBIR, but LD ASIR 2D image quality was slightly less than LD MBIR (p<.037). CONCLUSION 60% RD 2D and 3D CTC reconstructed with MBIR had less visual noise both objectively and subjectively compared to SD ASIR. Image quality on RD MBIR 2D and 3D CTC was not perceived to be significantly different compared to SD ASIR, but RD MBIR images were slightly better quality than comparable ASIR. CLINICAL RELEVANCE/APPLICATION Image quality was not compromised on RD MBIR images. Thus, CTC image quality can be maintained with 60% radiation dose reduction.
    No preview · Conference Paper · Dec 2013
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    ABSTRACT: We retrospectively evaluated computed tomographic colonography examinations of patients who have had a partial bowel preparation and compared the quality of their preparation with patients who have had a full bowel preparation. In total, 27 patients undergoing computed tomographic colonography examination (10 patients with partial bowel preparation and 17 with full bowel preparation) had their examinations retrospectively reviewed by three independent radiologists in a blinded manner, with evaluation of residual stool, distention, residual fluid, and overall bowel preparation quality. Six colon segments were evaluated individually and independently for these four variables (a total of 161 segments tested). Comparisons were made with the Mann-Whitney test between the partial preparation group and the full preparation group. Partial preparation included stool and fluid tagging plus 20 mg of bisacodyl orally; full preparation included stool and fluid tagging plus 2 L of polyethylene glycol solution. No significant clinical difference was found in colon preparation between the partial and full bowel preparation groups--when evaluated with individual colon segments or by independent readers. Interreader correlation was high. This pilot study indicates that full bowel preparation is not required for diagnostic-quality computed tomographic colonography examination. Further evaluation of this partial bowel preparation regimen is warranted.
    No preview · Article · May 2011 · Abdominal Imaging
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    ABSTRACT: To estimate and stratify the risk of development of nephrogenic systemic fibrosis (NSF) in well-defined at-risk subpopulations from a large single institution, and to perform a single-institution case series study of patients with biopsy-proven NSF. Retrospective cohort of patients exposed to gadolinium-based contrast agents (GBCAs) at a single institution during an 8-year period (January 1, 1999, to December 31, 2006), and a case series study of patients with biopsy-proven NSF. A primary, secondary, and tertiary health care center that treated more than 2.2 million outpatients and had 135 000 hospital admissions in 2007. Patients A total of 94 917 patients exposed to GBCAs; patients at risk for NSF (3779 patients on hemodialysis, 1694 patients with renal transplants, and 717 patients with liver transplants, a well-defined subgroup that includes patients at risk for reduced renal function); and 61 patients with a clinical diagnosis of NSF. Risk estimate for NSF. The risk of development of NSF is 1.0% for patients who undergo hemodialysis (8 of 827), 0.8% for patients with renal transplantation (4 of 527), and 0% for patients with liver transplantation at our institution (0 of 327). Despite the limitations, this study, which reviewed a large number of patients who underwent intravascular GBCA injections, demonstrates a 77-fold higher risk of NSF among patients who undergo hemodialysis and a 69-fold higher risk in patients with renal transplantation. This increased risk is thought to be associated with poor clearance of most GBCAs.
    No preview · Article · Oct 2009 · Archives of dermatology

  • No preview · Article · Oct 2008 · Surgery