Volume Of Contrast Medium Research Articles

Feasibility of Low-Dose and Low-Contrast Media Volume Approach in Computed Tomography Cardiovascular Imaging Reconstructed with Model-Based Algorithm.

Aim: To evaluate the dose reduction and image quality of low-dose, low-contrast media volume in computed tomography (CT) examinations reconstructed with the model-based iterative reconstruction (MBIR) algorithm in comparison with the hybrid iterative (HIR) one. Methods: We prospectively enrolled a total of 401 patients referred for cardiovascular CT, evaluated with a 256-MDCT scan with a low kVp (80 kVp) reconstructed with an MBIR (study group) or a standard HIR protocol (100 kVp-control group) after injection of a fixed dose of contrast medium volume. Vessel contrast enhancement and image noise were measured by placing the region of interest (ROI) in the left ventricle, ascending aorta; left, right and circumflex coronary arteries; main, right and left pulmonary arteries; aortic arch; and abdominal aorta. The signal-to-noise ratio (SNR) and contrast-to-noise ratio (CNR) were computed. Subjective image quality obtained by consensus was assessed by using a 4-point Likert scale. Radiation dose exposure was recorded. Results: HU values of the proximal tract of all coronary arteries; main, right and left pulmonary arteries; and of the aorta were significantly higher in the study group than in the control group (p < 0.05), while the noise was significantly lower (p < 0.05). SNR and CNR values in all anatomic districts were significantly higher in the study group (p < 0.05). MBIR subjective image quality was significantly higher than HIR in CCTA and CTPA protocols (p < 0.05). Radiation dose was significantly lower in the study group (p < 0.05). Conclusions: The MBIR algorithm combined with low-kVp can help reduce radiation dose exposure, reduce noise, and increase objective and subjective image quality.

Low-tube-voltage whole-body CT angiography with extremely low iodine dose: a comparison between hybrid-iterative reconstruction and deep-learning image-reconstruction algorithms

To evaluate arterial enhancement, its depiction, and image quality in low-tube potential whole-body computed tomography (CT) angiography (CTA) with extremely low iodine dose and compare the results with those obtained by hybrid-iterative reconstruction (IR) and deep-learning image-reconstruction (DLIR) methods. This prospective study included 34 consecutive participants (27 men; mean age, 74.2 years) who underwent whole-body CTA at 80 kVp for evaluating aortic diseases between January and July 2020. Contrast material (240 mg iodine/ml) with simultaneous administration of its quarter volume of saline, which corresponded to 192 mg iodine/ml, was administered. CT raw data were reconstructed using adaptive statistical IR-Veo of 40% (hybrid-IR), DLIR with medium- (DLIR-M), and high-strength level (DLIR-H). A radiologist measured CT attenuation of the arteries and background noise, and the signal-to-noise ratio (SNR) was then calculated. Two reviewers qualitatively evaluated the arterial depictions and diagnostic acceptability on axial, multiplanar-reformatted (MPR), and volume-rendered (VR) images. Mean contrast material volume and iodine weight administered were 64.1 ml and 15.4 g, respectively. The SNRs of the arteries were significantly higher in the following order of the DLIR-H, DLIR-M, and hybrid-IR (p<0.001). Depictions of six arteries on axial, three arteries on MPR, and four arteries on VR images were significantly superior in the DLIR-M or hybrid-IR than in the DLIR-H (p≤0.009 for each). Diagnostic acceptability was significantly better in the DLIR-M and DLIR-H than in the hybrid-IR (p<0.001-0.005). DLIR-M showed well-balanced arterial depictions and image quality compared with the hybrid-IR and DLIR-H.

Customised weight-based volume contrast media protocol for multiphase abdominal computed tomography.

Multiphase computed tomography (CT) using fixed volume contrast media may lead to high radiation exposure and toxicity in patients with low body weight. We evaluated a customised weight-based protocol for multiphase CT in terms of radiation exposure, image quality and cost savings. A total of 224 patients were recruited. An optimised CT protocol was applied using 100 kV and 1 mL/kg of contrast media dosing. The image quality and radiation dose exposure of this CT protocol were compared to those of a standard 120 kV, 80 mL fixed volume protocol. The radiation dose information and CT Hounsfield units were recorded. The signal-to-noise ratio, contrast-to-noise ratio (CNR) and figure of merit (FOM) were used as comparison metrics. The images were assessed for contrast opacification and visual quality by two radiologists. The renal function, contrast media volume and cost were also evaluated. The median effective dose was lowered by 16% in the optimised protocol, while the arterial phase images achieved significantly higher CNR and FOM. The radiologists' evaluation showed more than 97% absolute agreement with no significant differences in image quality. No significant differences were found in the pre- and post-CT estimated glomerular filtration rate. However, contrast media usage was significantly reduced by 1,680 mL, with an overall cost savings of USD 421 in the optimised protocol. The optimised weight-based protocol is cost-efficient and lowers radiation dose while maintaining overall contrast enhancement and image quality.

Dual-energy computed tomography in supporting prostatic artery embolization for benign prostatic hyperplasia.

Objective: Our study aims to evaluate the value of 256-slice dual-energy computed tomography (DECT) in supporting prostatic artery embolization (PAE) under digital subtraction angiography (DSA) for benign prostatic hyperplasia (BPH). Methods: The study was conducted on 88 patients who underwent PAE to treat BPH from January 2022 to November 2023. Of these, 38 patients who had PAE without DECT were placed in group 1, while the other 50 patients with pre-interventional DECT were assigned to group 2. The results of DECT imaging of the prostate artery (PA) were compared with the results of DSA imaging. Test for statistically significant differences between the variables of the two research groups using the T - student test and Mann-Whitney test algorithms with p < 0.05 corresponding to a 95% confidence interval. The data were analyzed according to medical statistical methods using SPSS 20.0 software. Results: DECT can detect the PA origin in 96.1% of cases, identify atherosclerosis at the root of the artery with a sensitivity of 66.7% and a specificity of 89.5%, and present anastomosis with a sensitivity of 72.7% and a specificity of 72.2%. There is no statistically significant difference in PA diameter on DECT compared to DSA with 95% confidence. Group 2 used DECT for 3D rendering of the PA before PAE had procedure time reduced by 25.8%, fluoroscopy time reduced by 23.2%, dose-area product (DAP) reduced by 25.6%, contrast medium volume reduced by 33.1% compared to group 1 not using DECT, statistically significant with 95% confidence. Conclusion: DECT is a valuable method for planning before PAE to treat BPH. 3D rendering DECT of PA provides anatomical information that minimizes procedure time, fluoroscopy time, dose-area product, and contrast medium volume.

Influence of splenomegaly on aortic and liver parenchymal CT numbers during contrast-enhance CT in patients with cirrhosis

IntroductionTo compare CT (computed tomography) values for enhancement of the abdominal aorta and liver parenchyma during dynamic contrast enhancement (CE) CT in cirrhotic patients with and without splenomegaly (SM). MethodsWe considered 258 patients (83 males and 46 females for the splenomegaly group, and 83 males and 46 females for the control group) for this retrospective study. We measured CT values in the abdominal aorta and hepatic parenchyma during the hepatic arterial (HAP) and portal venous (PVP) phases. The aortic CE at HAP and the hepatic parenchymal CE at PVP were compared between the two groups. For success rate of scans, we also calculated the optimal CE rates (>280 HU in the abdominal aorta and >50 HU in the hepatic parenchyma) for each group. ResultsIn the SM group, the CE for abdominal aorta was decreased during the aortic phase for a dynamic CE-CT (p < 0.05). When evaluating the success rates, they were found to be 65.1 % and 58.9 % in the SM group and 81.4 % and 72.3 % in the non-SM group (p < 0.05). ConclusionThe success rate of scans and CE for the abdominal aorta during the aortic phase exhibited a significant decrease during dynamic CE-CT scans on patients with SM. Patients with SM may have reduced diagnostic ability with typical contrast injection protocols. Implications for practiceIt may be necessary to change the injection rates and contrast medium volume during CE-CT depending on the presence or absence of SM.

Intravascular Imaging in Ultra-Low or Zero-Contrast Percutaneous Coronary Interventions: The Time Is Now?

Ultra-low contrast percutaneous coronary interventions (ULPCIs) are a novel field of interventional cardiology, aiming to reduce the risk of contrast-induced nephropathy (CIN), which is a well-described adverse event after angiography. CIN is a well-described adverse event following PCI, especially in high-risk patients, i.e., patients with an already deteriorating renal function or chronic kidney disease, as well as patients of advanced age or requiring an increased amount of contrast during their intervention. Among the techniques described for ULPCI procedures, intravascular imaging guidance seems a promising option, as it allows lesion recognition and characterization, stent implantation, and PCI optimization. Intravascular ultrasound (IVUS) is the modality most commonly used, as it does not require contrast injection, contrary to optical coherence tomography (OCT). Several clinical trials, assessing IVUS in the context of ULPCI, have shown that it can be safely used in this setting while offering a substantial reduction in contrast media volume, as well as renal adverse outcomes. This review aims to describe the need for ULPCI and technical considerations regarding the use of intravascular imaging in this setting, as well as analyze the available evidence from clinical trials regarding the safety and efficacy of IVUS-ULPCI, in order to provide a comprehensive summary for practicing physicians.

Comparação entre dois modelos de risco na predição de nefropatia induzida por contraste após angiotomografia coronariana e intervenção coronária percutânea

Background Contrast-induced nephropathy is one of the main causes of hospital-acquired acute renal failure. The Mehran risk score and the contrast medium volume used/creatinine clearance ratio could help identifying patients at higher risk of developing contrast-induced nephropathy. This study aimed to compare these two scores. Methods A retrospective, single-center observational study including hospitalized patients with baseline creatinine &gt;1.3mg/dL, under observation for at least 48 hours after coronary computed tomography angiography and/or percutaneous coronary intervention. Mehran risk score and contrast medium volume used/creatinine clearance ratio were calculated for all patients, and the incidence of contrast-induced nephropathy was analyzed according to different cutoff points of both scores. Receiver Operating Characteristic curves were plotted to determine the accuracy of the methods in predicting contrast-induced nephropathy. The effectiveness of both methods was analyzed using Pearson’s correlation test. Results We included 102 patients and the incidence of contrast-induced nephropathy was 27.4%. The outcome occurred in 24.7% of patients when Mehran risk score ≥6, in 32.7% when Mehran risk score ≥10, and in 57.8% when Mehran risk score ≥15, in 28.7% of patients with contrast medium volume used/creatinine clearance ratio ≥2, 29.8% with contrast medium volume used/creatinine clearance ratio ≥3, and 34.3% with contrast medium volume used/creatinine clearance ratio ≥5. Receiver Operating Characteristic curves demonstrated area under the curve with moderate predictive capacity for Mehran risk score (0.7), and reduced/borderline for contrast medium volume used/creatinine clearance ratio (0.6). The correlation between the two scores was moderate. Conclusion Mehran risk score demonstrated greater accuracy in predicting contrast-induced nephropathy when compared to contrast medium volume used/creatinine clearance ratio, however both presented similar values. The cutoff points with the closest incidence between the two scores were ≥10 for Mehran risk score (32.7%) and ≥5 for volume used/creatinine clearance ratio (34.3%).

Retrospective investigation of percutaneous coronary intervention (PCI) via distal radial approach/artery(dRA) in daily practice: possible adaptability of variety of patients, diagnosis, devices

Abstract Background Distal radial approach(dRA) that features puncturing radial artery at snuff box is becoming well known gradually and widely in the fields of interventional cardiology. Although there are some reports about dRA, safety, feasibility and compatibility of this procedure are still unclear. Methods Total of consecutive 90 PCI attempted via dRA procedure done by the operators who has experience of more than 20 dRA catheterization before from December 2020 to January 2023 at the University of Tokyo Hospital were retrospectively investigated. Distal radial artery puncture was done with echo-guided method just before the PCI procedure. Diameter of conventional radial artery(cRA) and dRA were measured. PCI strategy and devices were decided by the operators. Results About patient characteristics, mean age was 73±10 years old, consisting of 82.2%(74/90) male and 17.8%(16/90) female. Mean height/weight/BMI was 162.8±8.5 cm, 64.1±12.4 kg and 24.0±3.5, respectively. LVEF was 56.6±15.7%. Approach side of dRA was right in 74.4%(67/90) and left in 25.6%(23/90). Former dRA prcedeure of the same side was 20.0%(18/90). There were 7 cases(7.8%) of hemodialysis patients(non-AV fistula side). Concerning antithrombotics, 100%(80/80) were on DAPT and 18.9%(17/90) were on triple therapy(DAPT + warfarin or any DOAC:direct oral anticoagulant). The dRA success rate was 90.0%(81/90) and the procedure success rate was 100%(90/90). Diagnosis were STEMI: 5.6%(5/90), NSTEMI: 2.2%(2/90), unstable AP: 10.0%(9/90), stable(effort) AP: 18.9%(17/90), staged PCI: 25.6%(23/90) and other: 37.8%(34/90). Mean sheath insertion time was about 4 minutes (255±139 seconds). There are 3 CTO cases. Rotational atherectomy was used in 3.3%(3/80) and orbital atherectomy device was used in 5.0%(4/80). ELCA(excimer laser coronary angioplasty) was used in 6.3%(5/80). More than 1 DES was deployed in 75.0%(60/80), DCB(drug coated balloon) was used in 23.8%(19/80). Imaging devices were used in 100%(80/80) consists of IVUS: 92.5%(74/80), OCT: 12.5%(10/80) and both: 10.0%(8/80). Mean total radiation dose was 1324±809 mGy and mean volume of contrast medium was 141.6±55.6 ml. Bleeding, neurological and other major complication was 0%(0/80). Blood transfusion was performed in 1 case that is not related to procedure. Procedure related dissection or perforation of dRA was observed in 2 cases(2.2%). Occlusion of dRA was observed in 1 case(1.1%). Diameter of cRA and dRA was 2.6±0.7 mm and 2.3 mm±0.7 mm, respectively. Conclusions PCI via dRA had high rate of dRA and procedure success when it is performed by experienced physicians. It is effective regardless of the preprocedural diagnosis(STEMI/NETEMI/uAP/eAP/other). As far as this study is concerned, no device(including Rota, OAC and ELCA) had limitation or malfunction during procedure. No major complications was observed. PCI via dRA seemed to be safe, feasible, and compatible for various situations and devices.

Intravenous volume expansion to prevent contrast-associated acute kidney injury.

Several volume expansion protocols have been proposed to prevent contrast-associated acute kidney injury (CA-AKI). The aim of our study was to seek the ideal intravenous volume expansion to prevent CA-AKI in patients with chronic kidney disease (CKD) undergoing invasive cardiovascular procedures. We analyzed 1927 CKD patients enrolled in 6 studies that took place from September 15, 2000 to June 6, 2019. Four volume expansion regiments were included: (1) conventional group (n=625); (2) bicarbonate group (n=255); (3) left ventricular end-diastolic pressure-guided group (n=355); and (4) urine flow rate-guided group (n=500). CA-AKI (serum creatinine increase ≥0.3 mg/dL at 48 hours) occurred in 224 (11%) patients. In patients with CA-AKI, volume expansion was lower (2090 ± 1382 mL vs 2551 ± 1716 mL; P less than .001) and acute pulmonary edema occurred more often (3.5% vs 0.29%; P less than .001). By ROC curve analysis, an absolute volume expansion greater than or equal to 1430 mL (AUC = 0.70) and a volume expansion to contrast media volume ratio greater than or equal to 17 (AUC = 0.57) were the best thresholds for freedom from CA-AKI. In our comprehensive pooled analysis, an absolute volume expansion greater than or equal to 1430 mL and a volume expansion to contrast media volume ratio greater than or equal to 17 are the best dichotomous thresholds for CA-AKI prevention. These cutoffs should be formally tested in a dedicated trial as a pragmatic means to prevent CA-AKI.

Fusion imaging for pulmonary artery embolization: impact on fluoroscopy duration and contrast agent exposure.

To assess the impact of fusion imaging guidance on fluoroscopy duration and volume of contrast agent used for pulmonary artery embolization. Thirty-four consecutive patients who underwent pulmonary artery embolization for pulmonary arterio-venous malformation (n = 28) or hemoptysis (n = 6) were retrospectively included. In the experimental group (n = 15), patients were treated using fusion imaging with 2D/3D registration. In the control group (n = 19), no fusion imaging has been used. Fluoroscopy duration and amount of contrast used were measured and intergroup comparison was performed. The average volume of contrast agent used for embolization in the fusion group (118.3 ml) was significantly lower than in the control group (285.3 ml) (p < 0.002). The mean fluoroscopy duration was not significantly different between both groups (19.5 min in the fusion group vs 31.4 min in the control group (p = 0.10)). No significant difference was observed regarding the average X-ray exposure (Air Kerma) (p = 0.68 in the univariate analysis). Technical success rate was 100% for both groups. Fusion imaging significantly reduces contrast medium volumes needed to perform pulmonary artery embolization. The fluoroscopy duration and the X-ray exposure did not vary significantly. CTA-based fusion imaging using 2D-3D registration is a valuable tool for performing pulmonary artery embolization, helpful for planning and guiding catheterization.Compared to the traditional imaging guidance, fusion imaging reduces the volume of contrast agent used.

The Ratio of Contrast Volume/Glomerular Filtration Rate and Urine NGAL Predicts the Progression of Acute Kidney Injury to Chronic Kidney Disease in Patients After Planned Percutaneous Coronary Intervention.

To evaluate the value of contrast volume/glomerular filtration ratio (Vc/eGFR ratio) and urine Neutrophil Gelatinase-Associated Lipocalin (uNGAL) in predicting the progression contract associated-acute kidney injury (CA-AKI) to chronic kidney disease (CKD) in planned percutaneous coronary intervention (PCI) patients. We examined 387 adult patients who had undergone planned percutaneous coronary intervention (PCI). We determined acute kidney injury (AKI) and chronic kidney disease (CKD) using the criteria set by the Kidney Disease: Improving Global Outcomes (KDIGO). We calculated the estimated glomerular filtration rate (eGFR) using the CKD-EPI formula based on serum creatinine levels. To determine the Vc/eGFR ratio, we considered the contrast medium volume and eGFR for each patient. Additionally, we measured urine NGAL levels using the ELISA method. The percentage of CA-AKI patients who developed CKD after planned PCI was 36.36%. Within the CA-AKI to CKD group, the Vc/eGFR ratio was 2.82, and uNGAL levels were significantly higher at 72.74 ng/mL compared to 1.93 ng/mL for Vc/eGFR ratio and 46.57 ng/mL for uNGAL in the recovery CA-AKI group. This difference was statistically significant (p<0.001). Diabetic mellitus, urine NGAL concentration, and Vc/eGFR ratio were found to be independent factors in the progression of CA-AKI to CKD. The Vc/eGFR ratio and uNGAL showed predictive capabilities for progressing CA-AKI to CKD with an AUC of 0.884 and 0.878, respectively. The sensitivity was 81.3% for both, while the specificity was 89.3% for Vc/eGFR ratio and 85.7% for uNGAL. The Vc/eGFR ratio and uNGAL were good predictors for CA-AKI to CKD in planned PCI patients.

Clinical Outcomes of Patients with Chronic Kidney Disease Undergoing Percutaneous Coronary Interventions with a Novel Dynamic Coronary Roadmap System.

Dynamic coronary roadmap (DCR) is a novel technology that creates a real-time overlay of the coronary arteries in percutaneous coronary intervention (PCI) and has the potential to reduce the contrast volume. However, the efficacy of DCR in terms of clinical outcomes in patients with chronic kidney disease (CKD) remains to be fully elucidated.This single center retrospective study enrolled 275 patients with CKD who underwent PCI, and divided them into a DCR group (n = 124) and Non-DCR group (n = 151). Propensity score matching was performed to minimize the differences in baseline characteristics in 113 patient pairs. The primary endpoint was a composite outcome of all-cause death, hospitalization for heart failure, nonfatal myocardial infarction, or the introductory rate of dialysis within 2 years. The secondary endpoints were contrast medium volume, the incidence of contrast-induced acute kidney injury (CI-AKI), and the introductory rate of dialysis within 2 years.Although there was no significant difference in the success rate (DCR group: 99.1% versus Non-DCR group: 98.2%; P = 0.561), contrast volume (92.20 mL versus 115.97 mL; P = 0.002) was significantly lower in the DCR group. CI-AKI incidence was 0.9% versus 6.2% in the DCR and Non-DCR groups, respectively (P = 0.031). The composite outcome defined as primary endpoint occurred in 10 patients in the DCR group and 20 patients in the Non-DCR group (8.8% versus 17.7%; P = 0.049).From the perspective of acute and long-term clinical outcomes, DCR use may be effective for patients with CKD.

Reduced radiation dose and volume of contrast medium in heart rate-based, one-stop computed tomography angiography of coronary, carotid and cerebrovascular arteries.

Computed tomography angiography (CTA) is a reliable, non-invasive screening method for diagnosing panvascular disease. By using low contrast agent volume, CTA imaging enables one-stop multi-organ scanning, thereby minimizing the potential risk of contrast-induced nephropathy in patients with impaired renal function. To evaluate the feasibility of one-stop CTA following a heart rate (HR)-based protocol using a low volume of contrast medium (CM) for examination of the coronary, carotid and cerebrovascular arteries. Sixty patients undergoing coronary carotid, and cerebrovascular CTA after a single injection of CM were recruited and randomly divided into two groups. Group A (n = 30) underwent CTA following a traditional protocol. The timing of the scans in Group B (n = 30) was determined according to the patient's HR. The CT values for the thoracic aorta (432.2 ± 104.28 HU), anterior cerebral artery (303.96 ± 99.29 HU), and right coronary artery (366.70 ± 85.10 HU) in Group A did not differ significantly from those in Group B (445.80 ± 106.13, 293.73 ± 75.25 and 344.13 ± 111.04 HU, respectively). The qualities of most of the scanned images for both groups were scored as 3 or 4 (on a five-point scale). The radiation dose and the volume of CM were significantly higher in Group A (303.05 ± 110.95 mGy) (100 mL) than in Group B (239.46 ± 101.12 mGy) (50 mL). The radiation dose and volume of CM were significantly reduced in CTA following the HR-based protocol. The personalized administration of CM also simplified the scanning process.

Contrast media volume reduction with the DyeVertTM system to prevent acute kidney injury in stable patients undergoing coronary procedures.

Contrast associated acute kidney injury (CA-AKI) can lead to an increased risk of adverse events. Contrast media (CM) volume reduction has been advocated as a pivotal strategy to prevent CA-AKI in stable patients undergoing percutaneous coronary procedures. To compare the effectiveness of CM volume reduction with the DyeVertTM system versus conventional strategy in reducing the risk of CA-AKI. We prospectively collected data from 136 patients with stable coronary artery disease at high risk of CA-AKI treated with left ventricular end diastolic pressure (LVEDP)- guided hydration and undergoing interventions with the use of the DyeVertTM (Osprey Medical Inc.) system. Patients previously enrolled in the LVEDP-guided hydration arm of the "Renal Insufficiency Following Contrast MEDIA Administration triaL III" (REMEDIAL III) were considered as controls. Propensity score was used to perform 1:1 matching to adjust for major confounders. The primary outcome was the occurrence of CA-AKI, as defined by an absolute increase of creatinine values ≥0.3 mg/dL at 48 h. Patients in the DyeVert group were treated with a significant lower CM volume (median: 47.5 vs. 84.0 mL, p < 0.001). The trend in creatinine increase was lower (p = 0.004) and the Δ of creatinine (0-48 h) showed a higher drop (-0.18 vs. -0.10 mg/dL, p = 0.036) in the DyeVert group. The risk of CA-AKI was significantly lower in DyeVert group compared to control group (5.1% vs. 16.8%; odds ratio 0.27, 95% confidence interval [0.12-0.61]). CM volume reduction with the DyeVertTM system seems to be superior to conventional strategies in reducing the occurrence of CA-AKI.

High-pitch CT pulmonary angiography (CTPA) with ultra-low contrast medium volume for the detection of pulmonary embolism: a comparison with standard CTPA

ObjectiveTo investigate the feasibility and image quality of high-pitch CT pulmonary angiography (CTPA) with reduced iodine volume in normal weight patients.MethodsIn total, 81 normal weight patients undergoing CTPA for suspected pulmonary arterial embolism were retrospectively included: 41 in high-pitch mode with 20 mL of contrast medium (CM); and 40 with normal pitch and 50 mL of CM. Subjective image quality was assessed and rated on a 3-point scale. For objective image quality, attenuation and noise values were measured in all pulmonary arteries from the trunk to segmental level. Contrast-to-noise ratio (CNR) was calculated. Radiation dose estimations were recorded.ResultsThere were no statistically significant differences in patient and scan demographics between high-pitch and standard CTPA. Subjective image quality was rated good to excellent in over 90% of all exams with no significant group differences (p = 0.32). Median contrast opacification was lower in high-pitch CTPA (283.18 [216.06–368.67] HU, 386.81 [320.57–526.12] HU; p = 0.0001). CNR reached a minimum of eight in all segmented arteries, but was lower in high-pitch CTPA (8.79 [5.82–12.42], 11.01 [9.19–17.90]; p = 0.005). Median effective dose of high-pitch CTPA was lower (1.04 [0.72–1.27] mSv/mGy·cm; 1.49 [1.07–2.05] mSv/mGy·cm; p < 0.0001).ConclusionHigh-pitch CTPA using ultra-low contrast volume (20 mL) rendered diagnostic images for the detection of pulmonary arterial embolism in most instances. Compared to standard CTPA, the high-pitch CTPA exams with drastically reduced contrast medium volume had also concomitantly reduced radiation exposure. However, objective image quality of high-pitch CTPA was worse, though likely still within acceptable limits for confident diagnosis.Clinical relevanceThis study provides valuable insights on the performance of a high-pitch dual-source CTPA protocol, offering potential benefits in reducing contrast medium and radiation dose while maintaining sufficient image quality for accurate diagnosis in patients suspected of pulmonary embolism.Key Points• High-pitch CT pulmonary angiography (CTPA) with ultra-low volume of contrast medium and reduced radiation dose renders diagnostic examinations with comparable subjective image quality to standard CTPA in most patients.• Objective image quality of high-pitch CTPA is reduced compared to standard CTPA, but contrast opacification and contrast-to-noise ratio remain above diagnostic thresholds.• Challenges of high-pitch CTPA may potentially be encountered in patients with severe heart failure or when performing a Valsalva maneuver during the examination.

Effect of preoperative coronary CT for planning of percutaneous coronary intervention for complex chronic total occlusion (CTS-C-CTOPCI): study protocol for an open-label randomised controlled trial

BackgroundTreatment of chronic total occlusion (CTO) by percutaneous coronary intervention (PCI) is associated with the difficulty of guidewire manipulation through the occluded segment, particularly when there is hard tissue due to calcification. The purpose of this randomised controlled trial is to determine whether improved planning of CTO-PCI using coronary computed tomographic angiography (CCTA) (versus conventional angiography) increases success rates of wire crossing in ≤ 60 min in difficult cases.MethodsThis is a randomised controlled open-label multi-centre trial in a superiority framework with 1:1 allocation ratio. Participants (n = 130) will be randomised into two groups: the study group who will receive standard of care with the addition of preoperative coronary computed tomographic angiography (CT group), and the control group that will receive standard of care (angiography group). The primary endpoint will be the rate of successful wire crossing in ≤ 60 min in complex CTO (J-CTO ≥ 2). Wire crossing will be considered successful if TIMI flow 3 is restored and residual stenosis is < 30%. The safety endpoint will be mortality due to the intervention or major adverse cardiac events (MACE). Secondary endpoints are success rates at any time; total time of PCI; time of wire crossing; rate of PCI complications; radiation levels during PCI; volume of iodine contrast medium administered; and cost of the PCI.DiscussionThis randomised trial will provide insight into whether pre-procedural CCTA as opposed to conventional angiography for planning of CTO-PCI yield higher success rates of wire crossing in ≤ 60 min. Potential benefits of CCTA include shorter successful procedure times of CTO-PCI leading to less irradiation and contrast medium with lower complication rates.Trial registrationClinical Trials.gov NCT04549896. Registered on December 21, 2021.

Development and Validation of a Risk Model for Predicting Contrast-Associated Acute Kidney Injury in Patients With Cancer: Evaluation in Over 46,000 CT Examinations.

BACKGROUND. Patients with cancer undergo frequent CT examinations with iodinated contrast media and may be uniquely predisposed to contrast-associated acute kidney injury (CA-AKI). OBJECTIVE. The purpose of this study was to develop and validate a model for predicting the risk of CA-AKI after contrast-enhanced CT in patients with cancer. METHODS. This retrospective study included 25,184 adult patients (12,153 men, 13,031 women; mean age, 62.3 ± 13.7 [SD] years) with cancer who underwent 46,593 contrast-enhanced CT examinations between January 1, 2016, and June 20, 2020, at one of three academic medical centers. Information was recorded regarding demographics, malignancy type, medication use, baseline laboratory values, and comorbid conditions. CA-AKI was defined as a 0.3-mg/dL or greater increase in serum creatinine level from baseline within 48 hours after CT or a 1.5-fold or greater increase in the peak measurement within 14 days after CT. Multivariable models accounting for correlated data were used to identify risk factors for CA-AKI. A risk score for predicting CA-AKI was generated in a development set (n = 30,926) and tested in a validation set (n = 15,667). RESULTS. CA-AKI occurred after 5.8% (2682/46,593) of CT examinations. The final multivariable model for predicting CA-AKI included hematologic malignancy, diuretic use, angiotensin-converting enzyme inhibitor or angiotensin receptor blocker use, chronic kidney disease (CKD) stage 3a, CKD stage 3b, CKD stage 4 or 5, serum albumin level less than 3.0 g/dL, platelet count less than 150 × 103/μL, 1+ or greater proteinuria on baseline urinalysis, diabetes mellitus, heart failure, and contrast medium volume 100 mL or greater. A risk score (range, 0-53 points) was generated with these variables. The most points (13) were for CKD stage 4 or 5 and for albumin level less than 3 g/dL. The frequency of CA-AKI progressively increased in higher risk categories. For example, in the validation set, CA-AKI occurred after 2.2% of CT examinations in the lowest risk category (score ≤ 4) and after 32.7% of CT examinations in the highest risk category (score ≥ 30). The Hosmer-Lemeshow test result indicated that the risk score was a good fit (p = .40). CONCLUSION. A risk model in which readily available clinical data are used to predict the likelihood of CA-AKI after contrast-enhanced CT in patients with cancer was developed and validated. CLINICAL IMPACT. The model may help facilitate appropriate implementation of preventive measures in the care of patients at high risk of CA-AKI.

A new modified technique of dynamic CT myelography to detect dural tears in spontaneous intracranial hypotension

We propose a modified dynamic CT-myelography technique for patients with fast CSF leaks caused by ventral dural tears in order to reduce radiation exposure and complications. A fluoroscopy-guided lumbar puncture using an epidural anesthesia kit replaces a CT-guided lumbar puncture, and a smaller volume of less concentrated contrast media is used. This approach has advantages, including speeding up the procedure, reduced radiation exposure, and elimination of the risk of contrast injection into the epidural space.

Renal perfusion improvement in the perioperative period after unilateral endovascular revascularization in patients with atherosclerotic renal artery stenosis.

The clinical benefits of endovascular treatment in renal artery stenosis (RAS) remain controversial. This study used an intraoperative renal perfusion imaging technique, called flat-panel detector parenchymal blood volume imaging (FD-PBV), to observe the change in renal perfusion after endovascular treatment in RAS. In a prospective, single-center study, we assigned 30 patients with atherosclerotic RAS who underwent endovascular treatment between March 2016 and March 2021. The preoperative and postoperative results of renal perfusion, blood pressure, and renal function, were compared. Both median kidney volume (p < 0.001) and median preoperative mean density of contrast medium (MDCM) (p = 0.028) increased significantly after endovascular treatment. The ratio of postoperative and preoperative MDCM differed greatly among the patients. For patients with preoperative MDCM <304.0 HU (Subgroup A, 15 cases), MDCM significantly increased after treatment (p = 0.001) and 12 (80.0%) patients had more than 10% increase in renal perfusion. For patients who had relatively high preoperative renal perfusion (MDCM ≥304.0 HU, Subgroup B, 15 cases), preoperative and postoperative MDCM were similar (p = 0.776). On the other hand, the serum creatinine levels significantly decreased in Subgroup A (p = 0.033) and fewer antihypertensive drugs were used after endovascular revascularization (p = 0.041). The preoperative and postoperative creatinine levels and number of antihypertensive drugs were similar in Subgroup B. During the perioperative period, RAS patients with relatively low preoperative renal perfusion levels had greater improvement in renal perfusion, renal function, and blood pressure control after endovascular treatment. The improvement of renal function needs to be confirmed by long-term follow-up.

Optimal Abdominal CT Image Quality in Non-Lean Patients: Customization of CM Injection Protocols and Low-Energy Acquisitions.

We compared the image quality of abdominopelvic single-energy CT with 100 kVp (SECT-100 kVp) and dual-energy CT with 65 keV (DECT-65 keV) obtained with customized injection protocols to standard abdominopelvic CT scans (SECT-120 kVp) with fixed volumes of contrast media (CM). We retrospectively included 91 patients (mean age, 60.7 ± 15.8 years) with SECT-100 kVp and 83 (mean age, 60.3 ± 11.7 years) patients with DECT-65 keV in portovenous phase. Total body weight-based customized injection protocols were generated by a software using the following formula: patient weight (kg) × 0.40/contrast concentration (mgI/mL) × 1000. Patients had a prior abdominopelvic SECT-120 kVp with fixed injection. Iopamidol-370 was administered for all examinations. Quantitative and qualitative image quality comparisons were made between customized and fixed injection protocols. Compared to SECT-120 kVp, customized injection yielded a significant reduction in CM volume (mean difference = 9-12 mL; p ≤ 0.001) and injection rate (mean differences = 0.2-0.4 mL/s; p ≤ 0.001) in all weight categories. Improvements in attenuation, noise, signal-to-noise and contrast-to-noise ratios were observed for both SECT-100 kVp and DECT-65 keV compared to SECT-120 kVp in all weight categories (e.g., pancreas DECT-65 keV, 1.2-attenuation-fold increase vs. SECT-120 kVp; p < 0.001). Qualitative scores were ≥4 in 172 cases (98.8.4%) with customized injections and in all cases with fixed injections (100%). These findings suggest that customized CM injection protocols may substantially reduce iodine dose while yielding higher image quality in SECT-100 kVp and DECT-65 keV abdominopelvic scans compared to SECT-120 kVp using fixed CM volumes.