Automated tube potential selection for standard chest and abdominal CT in follow-up patients with testicular cancer: comparison with fixed tube potential

Objective: To evaluate prospectively, in patients with testicular cancer, the radiation dose-saving potential and image quality of contrast-enhanced chest and abdominal CT with automated tube potential selection. Methods: Forty consecutive patients with testicular cancer underwent contrast-enhanced arterio-venous chest and portal-venous abdominal CT with automated tube potential selection (protocol B; tube potential 80-140kVp), which is based on the attenuation of the CT topogram. All had a first CT at 120kVp (protocol A) using the same 64-section CT machine and similar settings. Image quality was assessed; dose information (CTDIvol) was noted. Results: Image noise and attenuation in the liver and spleen were significantly higher for protocol B (P < 0.05 each), whereas attenuation in the deltoid and erector spinae muscles was similar. In protocol B, tube potential was reduced to 100kVp in 18 chest and 33 abdominal examinations, and to 80kVp in 5 abdominal CT examinations; it increased to 140kVp in one patient. Image quality of examinations using both CT protocols was rated as diagnostic. CTDIvol was significantly lower for protocol B compared to protocol A (reduction by 12%, P < 0.01). Conclusion: In patients with testicular cancer, radiation dose of chest and abdominal CT can be reduced with automated tube potential selection, while image quality is preserve

Low-dose CT of the lung: potential value of iterative reconstructions

Objectives: To prospectively assess the impact of sinogram-affirmed iterative reconstruction (SAFIRE) on image quality of nonenhanced low-dose lung CT as compared to filtered back projection (FBP). Methods: Nonenhanced low-dose chest CT (tube current-time product: 30mAs) was performed on 30 patients at 100kVp and on 30 patients at 80kVp. Images were reconstructed with FBP and SAFIRE. Two blinded, independent readers measured image noise; two readers assessed image quality of normal anatomic lung structures on a five-point scale. Radiation dose parameters were recorded. Results: Image noise in datasets reconstructed with FBP (57.4 ± 15.9) was significantly higher than with SAFIRE (31.7 ± 9.8, P < 0.001). Image quality was significantly superior with SAFIRE than with FBP (P < 0.01), without significant difference between FBP at 100kVp and SAFIRE at 80kVp (P = 0.68). Diagnostic image quality was present with FBP in 96% of images at 100kVp and 88% at 80kVp, and with SAFIRE in 100% at 100kVp and 98% at 80kVp. There were significantly more datasets with diagnostic image quality with SAFIRE than with FBP (P < 0.01). Mean CTDIvol and effective doses were 1.5 ± 0.7mGy·cm and 0.7 ± 0.2mSv at 100kVp, and 1.4 ± 2.8mGy·cm and 0.5 ± 0.2mSv at 80kVp (P < 0.001, both). Conclusions: Use of SAFIRE in low-dose lung CT reduces noise, improves image quality, and renders more studies diagnostic as compared to FBP. Key Points : • Low-dose computed tomography is an important thoracic investigation tool. • Radiation dose can be less than 1mSv with iterative reconstructions. • Iterative reconstructions render more low-dose lung CTs diagnostic compared to conventional reconstruction

Raw data-based iterative reconstruction in body CTA: evaluation of radiation dose saving potential

Objective: To evaluate prospectively, in patients undergoing body CTA, the radiation dose saving potential of raw data-based iterative reconstruction as compared to filtered back projection (FBP). Methods: Twenty-five patients underwent thoraco-abdominal CTA with 128-slice dual-source CT, operating both tubes at 120kV. Full-dose (FD) images were reconstructed with FBP and were compared to half-dose (HD) images with FBP and HD-images with sinogram-affirmed iterative reconstruction (SAFIRE), both reconstructed using data from only one tube-detector-system. Image quality and sharpness of the aortic contour were assessed. Vessel attenuation and noise were measured, contrast-to-noise-ratio was calculated. Results: Noise as image quality deteriorating artefact occurred in 24/25 (96%) HD-FBP but not in FD-FBP and HD-raw data-based iterative reconstruction datasets (p  0.05). Lowest noise was found for HD-raw data-based iterative reconstruction (7.23HU), being 9.4% lower than that in FD-FBP (7.98HU, p 50% while maintaining image quality. Key Points • Raw data-based iterative reconstruction reduces image noise and improves image quality as compared to filtered back projection • At a similar radiation dose, raw data-based iterative reconstruction improves the sharpness of vessel contours • In body CTA a dose reduction of >50% might be possible when using raw data-based iterative reconstructions, while image quality can be maintaine

Automated tube potential selection for standard chest and abdominal CT in follow-up patients with testicular cancer: comparison with fixed tube potential

OBJECTIVE: To evaluate prospectively, in patients with testicular cancer, the radiation dose-saving potential and image quality of contrast-enhanced chest and abdominal CT with automated tube potential selection. METHODS: Forty consecutive patients with testicular cancer underwent contrast-enhanced arterio-venous chest and portal-venous abdominal CT with automated tube potential selection (protocol B; tube potential 80-140 kVp), which is based on the attenuation of the CT topogram. All had a first CT at 120 kVp (protocol A) using the same 64-section CT machine and similar settings. Image quality was assessed; dose information (CTDI(vol)) was noted. RESULTS: Image noise and attenuation in the liver and spleen were significantly higher for protocol B (P < 0.05 each), whereas attenuation in the deltoid and erector spinae muscles was similar. In protocol B, tube potential was reduced to 100 kVp in 18 chest and 33 abdominal examinations, and to 80 kVp in 5 abdominal CT examinations; it increased to 140 kVp in one patient. Image quality of examinations using both CT protocols was rated as diagnostic. CTDI(vol) was significantly lower for protocol B compared to protocol A (reduction by 12%, P < 0.01). CONCLUSION: In patients with testicular cancer, radiation dose of chest and abdominal CT can be reduced with automated tube potential selection, while image quality is preserved

Split-bolus dual-energy CT urography: protocol optimization and diagnostic performance for the detection of urinary stones

Purpose: Prospective protocol optimization, determination of image quality and diagnostic performance of virtual non-enhanced images (VNEI) derived from split-bolus dual-energy computed tomography (DECT) urography in patients with urinary stones. Methods: IRB-approved, prospective study of 100 patients who, after written informed consent, underwent single-energy, non-enhanced CT and split-bolus, contrast-enhanced DECT (30+50mL of contrast media; combined nephro-urographic acquisition). DECT was performed using setting A (80/140kVp) in the first 20, and setting B (100/140kVp) in the second 20 patients. Tin filtration was used in all patients. After a pre-analysis of VNEI quality, 60 additional patients were examined using setting B. Two readers qualitatively and quantitatively determined image quality of all weighted-average DECT images regarding urinary tract opacification (n=100), and all VNEI regarding quality of iodine subtraction and urinary stone detection (n=80). True nonenhanced (TNEI) images were the standard of reference for statistical analysis (inter-reader variability and diagnostic performance characteristics). Results: The urinary tract was completely opacified in 94% (94/100) of patients. Iodine subtraction was improved (p<0.01) and image noise of VNEI was lower (p<0.05) in DECT setting B. On VNEI, 83% (86/104) of urinary stones were correctly identified and 17% (18/104) were missed. Stones missed (2.5mm, 1-4) were significantly smaller than stones correctly identified (5mm, 2-27; p<0.001). Diagnostic accuracy was 98% on a per-renal-unit basis and 96% on a per-patient basis. Inter-reader agreements were excellent (κ=0.91-1.00; ICC=0.86-0.99). Conclusions: Split-bolus DECT urography was technically feasible and quality of VNEI was improved with the 100/140kVp setting. Detection of urinary stones <4mm on VNEI was limite

Association of Mortality and Risk of Epilepsy With Type of Acute Symptomatic Seizure After Ischemic Stroke and an Updated Prognostic Model

IMPORTANCE: Acute symptomatic seizures occurring within 7 days after ischemic stroke may be associated with an increased mortality and risk of epilepsy. It is unknown whether the type of acute symptomatic seizure influences this risk. OBJECTIVE: To compare mortality and risk of epilepsy following different types of acute symptomatic seizures. DESIGN, SETTING, AND PARTICIPANTS: This cohort study analyzed data acquired from 2002 to 2019 from 9 tertiary referral centers. The derivation cohort included adults from 7 cohorts and 2 case-control studies with neuroimaging-confirmed ischemic stroke and without a history of seizures. Replication in 3 separate cohorts included adults with acute symptomatic status epilepticus after neuroimaging-confirmed ischemic stroke. The final data analysis was performed in July 2022. EXPOSURES: Type of acute symptomatic seizure. MAIN OUTCOMES AND MEASURES: All-cause mortality and epilepsy (at least 1 unprovoked seizure presenting >7 days after stroke). RESULTS: A total of 4552 adults were included in the derivation cohort (2547 male participants [56%]; 2005 female [44%]; median age, 73 years [IQR, 62-81]). Acute symptomatic seizures occurred in 226 individuals (5%), of whom 8 (0.2%) presented with status epilepticus. In patients with acute symptomatic status epilepticus, 10-year mortality was 79% compared with 30% in those with short acute symptomatic seizures and 11% in those without seizures. The 10-year risk of epilepsy in stroke survivors with acute symptomatic status epilepticus was 81%, compared with 40% in survivors with short acute symptomatic seizures and 13% in survivors without seizures. In a replication cohort of 39 individuals with acute symptomatic status epilepticus after ischemic stroke (24 female; median age, 78 years), the 10-year risk of mortality and epilepsy was 76% and 88%, respectively. We updated a previously described prognostic model (SeLECT 2.0) with the type of acute symptomatic seizures as a covariate. SeLECT 2.0 successfully captured cases at high risk of poststroke epilepsy. CONCLUSIONS AND RELEVANCE: In this study, individuals with stroke and acute symptomatic seizures presenting as status epilepticus had a higher mortality and risk of epilepsy compared with those with short acute symptomatic seizures or no seizures. The SeLECT 2.0 prognostic model adequately reflected the risk of epilepsy in high-risk cases and may inform decisions on the continuation of antiseizure medication treatment and the methods and frequency of follow-up

Automated attenuation-based tube voltage selection for body CTA: Performance evaluation of 192-slice dual-source CT

OBJECTIVE To assess radiation dose and image quality in body CT-angiography (CTA) with automated attenuation-based tube voltage selection (ATVS) on a 192-slice dual-source CT (DSCT). METHODS Forty patients (69.5 ± 9.6 years) who had undergone body CTA with ATVS (ref.kVp 100, ref.mAs 90) using a 2x192-slice CT in single-source mode were retrospectively included. All patients had undergone prior CTA with a 2x128-slice CT and ATVS with identical imaging and contrast media protocols, serving for comparison. Images were reconstructed with iterative reconstruction at similar strength levels. Radiation dose was determined. Image quality was assessed semi-quantitatively (1:excellent, 5:non-diagnostic), aortic attenuation, noise and CNR were determined. RESULTS As compared to 128-slice DSCT, 192-slice DSCT selected tube voltages were lower in 30 patients (75 %), higher in 3 (7.5 %), and similar in 7 patients (17.5 %). CTDIvol was lower with 192-slice DSCT (4.7 ± 1.9 mGy vs. 5.8 ± 2.1 mGy; p < 0.001). Subjective image quality, mean aortic attenuation (342 ± 67HU vs. 268 ± 67HU) and CNR (9.8 ± 2.5 vs. 8.2 ± 2.9) were higher with 192-slice DSCT (all p < 0.01), all datasets being diagnostic. CONCLUSION Our study suggests that ATVS of 192-slice DSCT for body CTA is associated with an improved image quality and further radiation dose reduction of 19 % compared to 128-slice DSCT. KEY POINTS • 192-slice DSCT allows imaging from 70 kVp to 150 kVp at 10 kVp increments. • 192-slice DSCT allows for radiation-dose reduction in body-CTA with ATVS. • Subjective and objective image quality increase compared to 128-slice DSCT

Graft patency in long-term survivors after renovisceral debranching with VORTEC

PURPOSE This study was designed to evaluate retrospectively the long-term stent-graft patency after renovisceral revascularization with Viabahn Open Revascularization Technique (VORTEC) using computed tomography angiography (CTA) and magnetic resonance angiography (MRA). METHODS In 34 patients (seven women; mean age 72 ± 8 years) with aortic aneurysm, 63 renovisceral vessels (i.e., 54 renal, nine visceral arteries) were revascularized with VORTEC between 2004 and 2009. All patients obtained a pre- and postinterventional CTA and at least one follow-up CTA or MRA after 6 or more months following intervention (median follow up: 43 months). Detection of bypass occlusion, bypass stenosis, infolding, stent-graft fractures and dislocations, and kidney shrinkage were noted by two readers in consensus. Furthermore, mortality during follow-up was assessed using the medical report. RESULTS During follow-up, 12.6 % of stent-grafts occluded. Cumulative patency rate was 95.2 ± 2.7 % at 12 months, 87.7 ± 4.4 % at 24 and 36 months, and 84.7 ± 5.2 % at 48, 60, 72, 84, and 89 months, respectively. Overall, 19 % of stent-grafts (12/63) developed bypass stenosis ( 50 %, 2 stent-grafts), in one case stenosis (>70 %) was suspected to be hemodynamically significant. No secondary dislocation, no infolding of renovisceral stent-grafts, and no stent-graft fracture occurred. Kidney shrinkage occurred in nine patients, primarily in patients with an occluded Viabahn (n = 7). Eleven patients (32.3 %) died within the follow-up time period. CONCLUSIONS In long-term survivors after VORTEC cumulative patency rate remained high, and no stent-graft fractures or secondary dislocations occurred

MR imaging of degenerative disc disease

Magnet resonance imaging (MRI) is the most commonly used imaging modality for diagnosis of degenerative disc disease (DDD). Lack of precise observations and documentation of aspects within the complex entity of DDD might partially be the cause of poor correlation of radiographic findings to clinical symptoms. This literature review summarizes the current knowledge on MRI in DDD and outlines the diagnostic limitations. The review further sensitizes the reader toward awareness of potentially untended aspects of DDD and the interaction of DDD and endplate changes. A summary of the available classifications for DDD is provided

MRI signs helpful in the differentiation of patients with anterior ischaemic optic neuropathy and optic neuritis.

BACKGROUND/AIMS The aim of this study was to identify specific MRI characteristics of anterior ischaemic optic neuropathy (AION) and optic neuritis (ON) that would aid in the differentiation between these two diagnoses. METHODS We retrospectively analysed a consecutive case series including all patients with an MRI study of brain and orbit and the clinical diagnosis of either ON or AION. We examined the scans for restricted diffusion of the optic nerve, optic sheath diameter, enhancement and location of enhancement of the optic nerve and distribution of the white matter lesions. RESULTS Fifty patients met the inclusion criteria. We found an accuracy of 0.98 for the discrimination between AION and ON based solely on parameters extracted from MRI data. Dominance analysis to determine the most influential parameters showed that the enhancement pattern of the optic nerve and distribution of the white matter lesions had the biggest impact on the classification and led to a discrimination accuracy of 0.9 when used alone. CONCLUSION In patients with an inconclusive clinical diagnosis, optic nerve enhancement pattern and distribution of white matter lesions can aid in the diagnosis and differentiation between AION and ON. Diffusion-weighted imaging did not add significant information to the diagnosis or help to differentiate between the two conditions