Low-Dose CT in Pelvic Imaging: Comparing Dose and Image Quality in Relation to Clinical Value in a Phantom Study

Hackenbroch, Carsten; Feilhuber, Marius; Halt, Daniel; Riesner, Hans-Joachim; Beer, Meinrad; Wunderlich, Arthur

doi:10.2214/ajr.20.22907

Cited by 16 publications

(21 citation statements)

References 16 publications

Supporting

Mentioning

Contrasting

Unclassified

Order By: Relevance

“…It could be argued that the patient study lacked a trial arm with LD protocols without tin prefiltration to more clearly demonstrate the superiority of tin filter protocols. However, we already showed the superiority of LD CT examinations with tin filtration over radiographs and LD CT examination without tin filtration in follow-up MSK pelvic examinations in a previous phantom study 17 . Stern et al 60 already confirmed these results and described that LD CT with tin filtration were more dose efficient to LD CT without tin filtration for follow-up MSK imaging.…”

Section: Discussionmentioning

confidence: 55%

“…The superiority of LD CT examinations with tin filtration over radiographs in follow-up MSK pelvic examinations in a phantom study has already been described. 17 Following on from this, we first showed in the phantom study that LD protocols in general, and with additional tin filtration in particular are equal to standard ND protocols measured by objective and subjective image analysis for MSK imaging of the Difference between ND and Sn LD in percent relative to the ND protocol per patient category. Data are displayed as mean ± SEM.…”

Section: Discussionmentioning

confidence: 94%

See 1 more Smart Citation

Low-Dose CT Imaging of the Pelvis in Follow-up Examinations—Significant Dose Reduction and Impact of Tin Filtration

et al. 2022

Self Cite

View full text Add to dashboard Cite

Objectives: Low-dose (LD) computed tomography (CT) is still rarely used in musculoskeletal (MSK) radiology. This study evaluates the potentials of LD CT for follow-up pelvic imaging with special focus on tin filtration (Sn) technology for normal and obese patients with and without metal implants. Materials and Methods: In a phantom study, 5 different LD and normal-dose (ND) CT protocols with and without tin filtration were tested using a normal and an obese phantom. Iterative reconstruction (IR) and filtered back projection (FBP) were used for CT image reconstruction. In a subsequent retrospective patient study, ND CT images of 45 patients were compared with follow-up tin-filtered LD CT images with a 90% dose reduction. Sixty-four percent of patients contained metal implants at the follow-up examination. Computed tomography images were objectively (image noise, contrast-to-noise ratio [CNR], dose-normalized contrast-to-noise ratio [CNRD]) and subjectively, using a 6-point Likert score, evaluated. In addition, the figure of merit was calculated. For group comparisons, paired t tests, Wilcoxon signed rank test, analysis of variance, or Kruskal-Wallis tests were used, where applicable. Results: The LD Sn protocol with 67% dose reduction resulted in equal values in qualitative (Likert score) and quantitative image analysis (image noise) compared with the ND protocol in the phantom study. For follow-up examinations, dose could be reduced up to 90% by using Sn LD CT scans without impairment in the clinical study. However, metal implants resulted in a mild impairment of Sn LD as well as ND CT images. Cancellous bone (P < 0.001) was assessed worse and cortical bone ( P = 0.063) equally in Sn LD CT images compared with ND CT images. Figure of merit values were significant ( P ≤ 0.02) lower and hence better in Sn LD as in ND protocols. Obese patients benefited in particular from tin filtration in LD MSK imaging in terms of image noise and CNR ( P ≤ 0.05). Conclusions: Low-dose CT scans with tin filtration allow maximum dose reduction while maintaining high image quality for certain clinical purposes, for example, follow-up examinations, especially metal implant position, material loosening, and consolidation controls. Overweight patients benefit particularly from tin filter technology. Although metal implants decrease image quality in ND as well as in Sn LD CT images, this is not a relevant limitation for assessability.

show abstract

Section: Discussionmentioning

confidence: 55%

Section: Discussionmentioning

confidence: 94%

Low-Dose CT Imaging of the Pelvis in Follow-up Examinations—Significant Dose Reduction and Impact of Tin Filtration

et al. 2022

Self Cite

View full text Add to dashboard Cite

show abstract

“…To be able to further analyze and better compare clinical value in relation to the applied dose, we calculated a figure of merit (FOM) according to the following formula [31,32]: For an interreader agreement, a two-way mixed, agreement, single-measures intra-class correlation (ICC, R package: psych) was calculated and presented with 95% confidence intervals (CI). Results were assigned to poor (< 0.5), moderate (0.50-0.75), good (0.75-0.9) and excellent (> 0.90) interreader agreement [33].…”

Section: Figure Of Meritmentioning

confidence: 99%

Tin filter compared to low kV protocols - optimizing sinonasal imaging in computed tomography

et al. 2023

Self Cite

View full text Add to dashboard Cite

Objectives Paranasal sinus imaging due to chronic inflammatory disease is one of the most common examinations in head and neck radiology with CT imaging considered the current gold standard. In this phantom study we analyzed different low dose CT protocols in terms of image quality, radiation exposure and subjective evaluation in order to establish an optimized scanning protocol. Methods In a phantom study, an Alderson phantom was scanned using 12 protocols between 70–120 kV and 25–200 mAs with and without tin filtration. For all datasets, iterative reconstruction was used. Data were objectively evaluated (image noise, (dose-weighted) contrast-to-noise ratio) and for subjective evaluation an online survey using a Likert scale was performed to reach a large group of clinically experienced reader (n = 62). The protocol was considered diagnostically insufficient if the median score was 4 and above and if more than 10% of raters scored 4 and above on the Likert scale. For an interreader agreement an ICC was calculated. To compare clinical value in relation to the applied dose and the objective image parameters, we calculated a figure of merit (FOM) and ranked the protocols accordingly. Results There was an overall moderate agreement between the 62 readers for the 12 examined CT protocols. In this phantom study, protocols with 100 kV with spectral shaping and 50–100 mAs obtained the best results for its combination of dose, image quality and clinical information value for diagnosing sinusitis (FOM 1st– 2nd place) with the 70 kV and 50 mAs as a good alternative as well (Sinusitis: FOM shared 2nd). For preoperative planning, where a higher dose is necessary, 100 kV with spectral shaping and 100 mAs achieved the overall best results (FOM 1st place) with 70 kV and 50 mAs ranking 4th. Conclusion 100-kV protocols with spectral shaping or low kV protocols (70 kV) with a similarly low dose showed the best figure of merit for imaging sinonasal disease and preoperative planning. With modern scanner technology available, spectral shaping or low KV protocols should be used for sinusitis imaging.

show abstract

“…For quantitative image analysis, the standard deviation of background noise was determined and the contrast-to-noise ratio (CNR) was calculated using the following formula 31,32 :…”

Section: Quantitative Image Analysismentioning

confidence: 99%

Metal Artifact Reduction With Tin Prefiltration in Computed Tomography

Hackenbroch¹,

Schüle

Halt

et al. 2021

Invest Radiol

Self Cite

View full text Add to dashboard Cite

Objectives: With the aging population and thus rising numbers of orthopedic implants (OIs), metal artifacts (MAs) increasingly pose a problem for computed tomography (CT) examinations. In the study presented here, different MA reduction techniques (iterative metal artifact reduction software [iMAR], tin prefilter technique, and dual-energy CT [DECT]) were compared. Materials and Methods: Four human cadaver pelvises with OIs were scanned on a third-generation DECT scanner using tin prefilter (Sn), dual-energy (DE), and conventional protocols. Virtual monoenergetic CT images were generated from DE data sets. Postprocessing of CT images was performed using iMAR. Qualitative (bony structures, MA, image noise) image analysis using a 6-point Likert scale and quantitative image analysis (contrast-to-noise ratio, standard deviation of background noise) were performed by 2 observers. Statistical testing was performed using Friedman test with Nemenyi test as a post hoc test. Results: The iMAR Sn 150 kV protocol provided the best overall assessability of bony structures and the lowest subjective image noise. The iMAR DE protocol and virtual monochromatic image (VMI) ± iMAR achieved the most effective metal artifact reduction (MAR) (P < 0.05 compared with conventional protocols). Bony structures were rated worse in VMI ± iMAR (P < 0.05) than in tin prefilter protocols ± iMAR. The DE protocol ± iMAR had the lowest contrast-to-noise ratio (P < 0.05 compared with iMAR standard) and the highest image noise (P < 0.05 compared with iMAR VMI). The iMAR reduced MA very efficiently. Conclusions: When considering MAR and image quality, the iMAR Sn 150 kV protocol performed best overall in CT images with OI. The iMAR generated new artifacts that impaired image quality. The DECT/VMI reduced MA best, but experienced from a lack of resolution of bony fine structures.

show abstract

Low-Dose CT in Pelvic Imaging: Comparing Dose and Image Quality in Relation to Clinical Value in a Phantom Study

Cited by 16 publications

References 16 publications

Low-Dose CT Imaging of the Pelvis in Follow-up Examinations—Significant Dose Reduction and Impact of Tin Filtration

Low-Dose CT Imaging of the Pelvis in Follow-up Examinations—Significant Dose Reduction and Impact of Tin Filtration

Tin filter compared to low kV protocols - optimizing sinonasal imaging in computed tomography

Metal Artifact Reduction With Tin Prefiltration in Computed Tomography

Contact Info

Product

Resources

About