Effect of reduced z-axis scan coverage on diagnostic performance and radiation dose of neck computed tomography in patients with suspected cervical abscess

Weiß, Jakob; Maurer, Michael; Ketelsen, Dominik; Notohamiprodjo, Mike; Zinsser, Dominik; Wichmann, Julian L.; Nikolaou, Konstantin; Bamberg, Fabian; Othman, Ahmed E.

doi:10.1371/journal.pone.0180671

Cited by 8 publications

(7 citation statements)

References 29 publications

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“…Our results are relevant because a large proportion of patients with cervical abscesses are young adults. Thus, a dose-reduced examination in these patients would be desirable [ 12 , 22 ]. Previous studies have already shown that a reduction in the scan area or a lowering of the tube voltage can result in a substantial dose reduction in patients with suspected cervical abscesses [ 10 , 12 ].…”

Section: Discussionmentioning

confidence: 99%

“…To ensure imaging is undertaken according to according to the safety principle ALARA (as low as reasonably achievable), strategies to reduce radiation dose for patients are necessary. Various technical approaches for dose reduction have been developed, including modulation of tube current, automatic selection of tube voltage, reduced kVp settings, and reduction of z -axis scan coverage [ 10 , 11 , 12 ]. Lowering the radiation dose with standard filter back projection (FBP) will result in increased noise levels of the images with decreasing diagnostic confidence [ 13 ].…”

Section: Introductionmentioning

confidence: 99%

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Diagnostic Performance of Different Simulated Low-Dose Levels in Patients with Suspected Cervical Abscess Using a Third-Generation Dual-Source CT Scanner

Winkelmann¹,

Afat²,

Walter³

et al. 2020

Diagnostics

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The aim of this study was to investigate the effects of dose reduction on diagnostic accuracy and image quality of cervical computed tomography (CT) in patients with suspected cervical abscess. Forty-eight patients (mean age 45.5 years) received a CT for suspected cervical abscess. Low-dose CT (LDCT) datasets with 25%, 50%, and 75% of the original dose were generated with a realistic simulation. The image data were reconstructed with filtered back projection (FBP) and with advanced modeled iterative reconstruction (ADMIRE) (strengths 3 and 5). A five-point Likert scale was used to assess subjective image quality and diagnostic confidence. The signal-to-noise ratio (SNR) of the sternocleidomastoid muscle and submandibular gland and the contrast-to-noise ratio (CNR) of the sternocleidomastoid muscle and submandibular glandular fat were calculated to assess the objective image quality. Diagnostic accuracy was calculated for LDCT using the original dose as the reference standard. The prevalence of cervical abscesses was high (72.9%) in the cohort; the mean effective dose for all 48 scans was 1.8 ± 0.8 mSv. Sternocleidomastoid and submandibular SNR and sternocleidomastoid muscle fat and submandibular gland fat CNR increased with higher doses and were significantly higher for ADMIRE compared to FBP, with the best results in ADMIRE 5 (all p < 0.001). Subjective image quality was highest for ADMIRE 5 at 75% and lowest for FBP at 25% of the original dose (p < 0.001). Diagnostic confidence was highest for ADMIRE 5 at 75% and lowest for FBP at 25% (p < 0.001). Patient-based diagnostic accuracy was high for all LDCT datasets, down to 25% for ADMIRE 3 and 5 (sensitivity: 100%; specificity: 100%) and lower for FBP at 25% dose reduction (sensitivity: 88.6–94.3%; specificity: 92.3–100%). The use of a modern dual-source CT of the third generation and iterative reconstruction allows a reduction in the radiation dose to 25% (0.5 mSv) of the original dose with the same diagnostic accuracy for the assessment of neck abscesses.

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Section: Discussionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Diagnostic Performance of Different Simulated Low-Dose Levels in Patients with Suspected Cervical Abscess Using a Third-Generation Dual-Source CT Scanner

Winkelmann¹,

Afat²,

Walter³

et al. 2020

Diagnostics

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“…The ability of HRCT scans to resolve cysts and the resulting accuracy of cyst score were evaluated in a group of LAM patients. Limited or reduced Z length scans have been used previously in abdominal, neck and chest CTs in both adults and children as a way to reduce radiation dose T [18][19][20][21][22][23][24]. The specific UH re-scan of this study has been optimized for best resolution in a systematic chest phantom study previously [17].…”

Section: Introductionmentioning

confidence: 99%

Clinical CT underestimation of the percentage volume occupied by cysts in patients with lymphangioleiomyomatosis

et al. 2020

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To evaluate the accuracy of cyst score measurements by standard high-resolution helical volume chest CT (HRCT) in patients with lymphangioleiomyomatosis (LAM), using a short z-length ultra-high resolution rescan (UH re-scan) as the reference. In cystic lung diseases, cyst score is derived from CT scans and defined as the percentage of the total lung parenchymal volume occupied by cysts, a biomarker which measures the severity of the disease. Methods: In a prospective study of 73 LAM patients, each patient received the standard HRCT chest scan and a short z-length UH re-scan. Cyst scores were acquired from both scans using a standard FDA-approved scoring software on the CT scanner. Results: The limited UH re-scan resolved small cysts that were not resolved in the HRCT. The HRCT-derived cyst scores were on average 59.6% of the reference values from the UH re-scan (p = 4.7e-25). The amount of underestimation by HRCT varied from patient to patient, with an inter-quartile range of 29.8% and standard deviation of 20.7%. The overall trend was more pronounced underestimation for patients with lower cyst scores. For patients whose reference cyst scores were below 15 (n = 29), the HRCT cyst scores were 46.9 ± 21.6% of reference values (p = 7.4e-12), while for the rest of the patients (n = 44) the HRCT cyst scores were 68.0 ± 15.3% of reference values (p = 1.2E-19). Reconstructing the HRCT images to the resolution of the UH re-scan further widened the spread of the discrepancy between HRCT and reference values due to increased image noise, and did not provide accurate cyst scores. Conclusion: Cyst scores derived from standard high-resolution helical volume chest CT significantly underestimates the percentage lung volume occupied by cysts. This inaccuracy needs to be taken into consideration when cyst score is used as part of the CT assessment of the patient's condition.

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“…Because of the arising in health awareness, an increasing number of people have become concerned about the radiation dose in using X-ray CT [16–19]. Studies have reported that an excessive X-ray dose increases the risk of tissue diseases and cancers [20–23].…”

Section: Introductionmentioning

confidence: 99%

Performance of sparse-view CT reconstruction with multi-directional gradient operators

et al. 2019

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To further reduce the noise and artifacts in the reconstructed image of sparse-view CT, we have modified the traditional total variation (TV) methods, which only calculate the gradient variations in x and y directions, and have proposed 8- and 26-directional (the multi-directional) gradient operators for TV calculation to improve the quality of reconstructed images. Different from traditional TV methods, the proposed 8- and 26-directional gradient operators additionally consider the diagonal directions in TV calculation. The proposed method preserves more information from original tomographic data in the step of gradient transform to obtain better reconstruction image qualities. Our algorithms were tested using two-dimensional Shepp–Logan phantom and three-dimensional clinical CT images. Results were evaluated using the root-mean-square error (RMSE), peak signal-to-noise ratio (PSNR), and universal quality index (UQI). All the experiment results show that the sparse-view CT images reconstructed using the proposed 8- and 26-directional gradient operators are superior to those reconstructed by traditional TV methods. Qualitative and quantitative analyses indicate that the more number of directions that the gradient operator has, the better images can be reconstructed. The 8- and 26-directional gradient operators we proposed have better capability to reduce noise and artifacts than traditional TV methods, and they are applicable to be applied to and combined with existing CT reconstruction algorithms derived from CS theory to produce better image quality in sparse-view reconstruction.

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Effect of reduced z-axis scan coverage on diagnostic performance and radiation dose of neck computed tomography in patients with suspected cervical abscess

Cited by 8 publications

References 29 publications

Diagnostic Performance of Different Simulated Low-Dose Levels in Patients with Suspected Cervical Abscess Using a Third-Generation Dual-Source CT Scanner

Diagnostic Performance of Different Simulated Low-Dose Levels in Patients with Suspected Cervical Abscess Using a Third-Generation Dual-Source CT Scanner

Clinical CT underestimation of the percentage volume occupied by cysts in patients with lymphangioleiomyomatosis

Performance of sparse-view CT reconstruction with multi-directional gradient operators

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