Low-Dose Fluoroscopy Protocol for Diagnostic Cerebral Angiography.

Recent research on radiation exposure in minimally invasive surgery for transforaminal lumbar interbody fusion (MIS TLIF) has led to the development of a low-dose radiation fluoroscopy protocol, with resulting reductions in fluoroscopy times and radiation exposures. To prospectively evaluate a previously reported low-dose radiation fluoroscopy protocol for MIS TLIF. A prospective evaluation of the low-dose radiation fluoroscopy protocol for MIS TLIF was performed for 65 consecutive patients. Total fluoroscopy time, radiation dose, and operative times were prospectively analyzed for all enrolled patients. Sixty-five consecutive patients (43 women; 22 men) who underwent an MIS TLIF were prospectively enrolled in this study of the low-dose fluoroscopy protocol. A total of 260 pedicle screws were placed. The mean age of the patients was 63 years (range, 46-82 years). They had a mean operative time of 178.7 minutes (range, 119-247 minutes), a mean fluoroscopic time of 10.43 seconds (range, 5-24 seconds), and a mean radiation dose of 0.295 mGy × m2 (range, 0.092-0.314 mGy × m2). The combination of low-dose pulsed images and digital spot images in a low-dose protocol decreases fluoroscopy times and radiation doses in patients undergoing MIS TLIF without compromising visualization of the bony anatomy or the safety and efficiency of the procedure. The application of this low-dose protocol uncouples the otherwise linear relationship between fluoroscopy times and radiation dose. This is due primarily to the use of the digital spot technique. Equal emphasis should be placed on radiation dose and acquisition time to optimize this protocol.

Transradial access (TRA) has emerged as a promising alternative to standard transfemoral access (TFA) for interventional cardiac procedures, but its application for examination of the cerebral circulation has not been tested in a clinical trial. To compare the efficacy and safety of TRA with TFA for diagnostic cerebral angiography. This investigator-initiated, multicenter, open-label, noninferiority randomized clinical trial with a blinded outcome assessment was conducted at 13 sites in China. Patients eligible for cerebral angiography were randomized between September 15, 2023, and November 4, 2024, with final follow-up performed on November 27, 2024. The primary analysis was performed in the intention-to-treat population; secondary analyses were performed in the per-protocol population. Patients were randomly allocated to TRA (n = 431) or TFA (n = 430) for diagnostic cerebral angiography. The primary outcome was the success of diagnostic cerebral angiography. Secondary outcomes were success in achieving an accurate diagnosis, duration of angiography and fluoroscopy, time in bed, and patient-reported satisfaction on an 11-point visual analog scale for pain (ranging from 0 [none] to 10 [worst possible]) within 24 hours after the procedure. The noninferiority margin was an absolute difference of 5% in success of angiographic diagnosis and success of accurate diagnosis. A total of 858 patients (median age, 58.4 [IQR, 52.0-67.0] years; 479 [55.8%] male) completed the trial. Success of diagnostic cerebral angiography in the TRA group was lower than that in the TFA group (392 of 431 [91.0%] vs 409 of 427 [95.8%]; difference, -4.8 percentage points [pp] [95% CI, -8.1 to -1.5 pp]; relative risk [RR], 0.95 [95% CI, 0.92-0.98]; P = .46 for noninferiority test). The success rate of accurate diagnosis was 78.9% in the TRA group vs 91.1% in the TFA group (difference, -12.2 pp [95% CI, -16.9 to -7.5 pp]; RR, 0.87 [95% CI, 0.82-0.92]; P = .99 for noninferiority test). Compared with the TFA group, the TRA group had longer median times for angiography (33.7 [IQR, 23.0-40.0] vs 38.7 [IQR, 26.0-47.0] minutes; P < .001) and fluoroscopy (10.6 [IQR, 5.6-12.9] vs 11.8 [IQR, 6.2-15.0] minutes; P = .02); the TRA group had significantly shorter median time in bed (188.4 [IQR, 3.0-180.0] vs 1079.0 [IQR, 842.0-1366.0] minutes; P < .001) and lower median pain scores (0.5 [IQR, 0.0-1.0] vs 0.7 [IQR, 0.0-1.0]; P < .001). Overall angiography complications were comparable between the groups (19 of 445 [4.3%] vs 25 of 413 [6.1%]; P = .28), but TRA had more radial artery puncture failures than TFA. In this randomized clinical trial of patients undergoing diagnostic cerebral angiography, TRA was not shown to be noninferior to TFA with regard to the success rate of diagnostic cerebral angiography. Additional research, including superiority trials, is needed to clearly define the comparative benefits of TRA and TFA. ClinicalTrials.gov Identifier: NCT05401669.

Tin-filtered 100 kV Ultra-low-dose Abdominal CT for Calculi Detection in the Urinary Tract: A Comparative Study of 510 Cases

The guided angiography system, an integrated angiography system, enables continuous guidance and flushing during diagnostic procedures. A guidewire provides guidance by remaining inside the catheter during contrast injection into tortuous vessels. While its feasibility was demonstrated in a retrospective study, this randomized controlled trial aims to evaluate its safety and effectiveness. This single-center, single-blind, randomized controlled trial was conducted from September 2021 to June 2022. Patients with unruptured intracranial aneurysms were enrolled and randomly assigned to either the guided or the conventional group. Primary outcomes were procedural time and serious adverse events. Secondary outcomes included catheterization success, adverse events, fluoroscopy time, fluoroscopy dose, and image quality. A total of 200 participants (mean age, 59 [SD, 10 years], 71% women) were randomized into the guided (n = 100) and the conventional (n = 100) groups. The guided group demonstrated shorter procedural times compared with the conventional group (18.3 [SD, 9.2] versus 21.3 [SD, 8.1] minutes, P < .001). There were no serious adverse events in either group, and adverse events were similar. Catheterization success rates were similar between the guided and conventional groups (93.9% versus 96.8%, P = .226). However, the guided angiography system backed up more catheterization failures from the conventional angiography system, but not vice versa (57.1% versus 11.1%, P = .003). Among catheterization successes, the guided group achieved shorter fluoroscopy time (7.0 versus 7.7 minutes, P = .033) and lower fluoroscopy dose (466.8 versus 566.5 μGy·m2, P = .015). Regarding imaging quality, clinical acceptability was comparable between the guided and conventional groups (95.3% versus 95.5%, P = .781). The guided angiography system offers a simple and effective alternative for diagnostic cerebral conventional angiography, with reduced radiation exposure and a favorable safety profile.

To compare patients' radiation exposure, technical feasibility, imaging quality and complication rate of percutaneous lung biopsies (PLBs) performed with a low-dose (LD) CT protocol under guidance of an optical navigation system. Fifty-two consecutive patients with suspected malignant lung lesions were enrolled and randomised into group 1 (PLBs under the guidance of the navigation system) and group 2 (PLBs under the guidance navigation system with an LD protocol). Patients' demographics, lesion features, procedure-related variables and CT image quality for group 2 were recorded and compared. Technical success was 100 % in both groups. The radiation dose to patients' chest was significantly lower in group 2 than in group 1 (group 1: mean TDLP 206 ± 59 mGy·cm, ~ 3.5 ± 1.0 mSv; group 2: 54.2 ± 46.2 mGy·cm, ~ 0.92 ± 0.78 mSv; P < 0.0001). The PNX rate was 12 % in group 1 and 11.1 % in group 2. The haemoptysis rate was 8.0 % in group 1 and 3.7 % in group 2. CT image quality obtained in group 2 was always rated as adequate and as excellent in 15 cases (56.0 %). An optical navigation system with LD CT protocol is useful for performing lung biopsies with decreased patient radiation exposure. • Navigation systems are useful tools in percutaneous imaging-guided procedures. • For lung biopsies, low-dose (LD) CT protocols may be used. • Combining LD protocols with optical CT navigation results in significantly reduced radiation exposure.

Operator experience, the use of low frame rates during both fluoroscopy and DSA, and the application of modern medical equipment are crucial for ensuring optimal image quality while maintaining minimal exposure to ionising radiation during cerebral angiography. Our centre achieves this by using the lowest possible fluoroscopy frame rate (3.125 frames per second), a the operator set the nominal acquisition parameters at 2 fps for digital subtraction angiography (DSA), three-dimensional (3D) rotational angiography, two-dimensional /3D mapping, and roadmapping, without compromising the quality of the images obtained. A total of 213 diagnostic procedures for intracranial aneurysms, performed at a single medical centre between 2018 and 2024, were analyzed. Key exposure parameters were collected and analyzed for each procedure, including dose area product (DAP), air kerma (Ka,r), fluoroscopy time (FT), and the total number of DSA frames. The local diagnostic reference level (DRL) and typical values for cerebral angiography were determined and compared with data available in the relevant literature. The 75th percentile (P75) values, assumed to be the DRL, were 23.57 Gy · cm2for DAP (literature range: 90-209), 153 mGy for Ka,r (literature range: 711.3-1401 mGy), 10 min and 46 s for FT, and 257 for the number of DSA frames during diagnostic procedures. Typical values (50th percentile [P50]) were 13.4 Gy · cm2for DAP (literature range: 43.1-157), 92 mGy for Ka,r (literature range: 312-598 mGy), six minutes and 20 s for FT, and 182 for the number of DSA frames during diagnostic procedures. The P50 dose DRLs, measured via DAP, Ka,r, FT, and the number of DSA frames, were at least three times lower at our facility than those reported in studies on cerebral angiography published between 2013 and 2023. The use of low frame rates during both fluoroscopy and DSA has a significant impact on the radiation dose measured by DAP, Ka,r, FT, and the number of DSA frames. The proposed DRLs could be used to ensure quality and patient safety in diagnostic procedures.

Effectiveness of a low contrast load CT angiography protocol in octogenarians and nonagenarians being evaluated for transcatheter aortic valve replacement

Hypokalemia in children following cardiac surgery occurs frequently, placing them at risk of life-threatening arrhythmias. However, renal insufficiency after cardiopulmonary bypass warrants careful administration of potassium (K+). Two different nurse-driven protocols (high dose and tiered dosing) were implemented to identify an optimal K+ replacement regimen, compared to an historical low-dose protocol. Our objective was to evaluate the safety, efficacy, and timeliness of these protocols. A retrospective cohort review of pediatric patients placed on intravenous K+ replacement protocols over 1 year was used to determine efficacy and safety of the protocols. A prospective single-blinded review of K+ repletion was used to determine timeliness. Pediatric patients with congenital or acquired cardiac disease. Twenty-four-bed cardiothoracic intensive care unit in a tertiary children's hospital. Efficacy was defined as fewer supplemental potassium chloride (KCl) doses, as well as a higher protocol to total doses ratio per patient. Safety was defined as a lower percentage of serum K+ levels ≥4.8 mEq/L after a dose of KCl. Between-group differences were assessed by nonparametric univariate analysis. There were 138 patients with a median age of 3.0 (interquartile range: 0.23-10.0) months. The incidence of K+ levels ≥4.8 mEq/L after a protocol dose was higher in the high-dose protocol versus the tiered-dosing protocol but not different between the low-dose and tiered-dosing protocols (high dose = 2.2% vs tiered dosing = 0.5%, P = .05). The ratio of protocol doses to total doses per patient was lower in the low-dose protocol compared to the tiered-dosing protocol (P < .05). Protocol doses were administered 45 minutes faster (P < .001). The tiered-dosed, nurse-driven K+ replacement protocol was associated with decreased supplemental K+ doses without increased risk of hyperkalemia, administering doses faster than individually ordered doses; the protocol was effective, safe, and timely in the treatment of hypokalemia in pediatric patients after cardiac surgery.

Introduction Reversible cerebral vasoconstriction syndrome (RCVS) is a less considered etiology of acute severe headache in the pediatric population. It is classically characterized by thunderclap headache that is recurrent and reversible multifocal cerebral artery narrowing. While it has been linked to vasoactive medication, immunosuppression, and systemic illness, case reports in the field of pediatric hematology‐oncology are rare. No previous cases have linked RCVS with tovorafenib, an oral pan‐RAF inhibitor in clinical investigation for pediatric BRAF V600E‐mutated malignancies. Because RCVS can be imitated by other neurologic disorders and noninvasive vascular testing can be normal, the diagnosis usually necessitates catheter‐based angiography. Intra‐arterial calcium channel blockers have been utilized in endovascular therapy to obtain both diagnostic accuracy and immediate therapeutic benefit. We describe the first documented case of childhood RCVS associated with tovorafenib with successful endovascular diagnosis and intra‐arterial verapamil treatment. Materials and Methods A 12‐year‐old female with multifocal osseous relapsed Langerhans cell histiocytosis (LCH) harboring BRAF V600E mutation started tovorafenib in February 2025. After six cycles, she developed recurrent thunderclap headache that woke her up from sleep, sometimes followed by brief confusion characteristic of postictal states. Tovorafenib was withheld, and she was evaluated via multidisciplinary evaluation. Comparison brain MRI revealed minimal Chiari I malformation and small sphenoid hyperintensity on the left side. Head and neck CT angiogram was normal. EEG, with 2‐hour study during symptomatic attack, revealed no epileptiform discharge. Ophthalmological examination revealed no papilledema. Because of the persistence of thunderclap headache and nonrevealing noninvasive studies, diagnostic cerebral angiography was done. Results Digital subtraction angiography disclosed focal segmental narrowing of the right A3 segment of the anterior cerebral artery characteristic of RCVS. Verapamil (5 mg) was administered intra‐arterially, with resultant immediate angiographic resolution of the vasospasm. Lumbar puncture ruled out infection and inflammation. The patient was switched to oral verapamil with rapid resolution of her thunderclap headaches. Interestingly, tovorafenib was resumed on hospitalization day with continuation of verapamil, and no additional RCVS events were experienced. Discharge on oral verapamil with follow‐up as scheduled in neurology, neurosurgery, and oncology clinics was successful. Conclusion This case highlights the critical importance of endovascular evaluation and treatment of potential pediatric RCVS, especially when vasoconstriction is not detected by noninvasive imaging. In this patient, both therapeutic and diagnostic angiography was in keeping with RCVS and reversible following intra‐arterial verapamil infusion. Temporal correlation of tovorafenib exposure and onset of symptoms, together with angiographic response to calcium channel blockade, is compatible with drug‐related mechanism. One possible explanation would be inhibition of RAF pathway altering vascular smooth muscle or endothelial tone, which predisposes to vasoconstriction. To our knowledge, this is the first description of tovorafenib‐associated RCVS. This presentation underscores the need to heighten awareness of RCVS as an emergent side effect of new targeted therapies in children. Early diagnosis, multidisciplinary assessment, and prompt endovascular therapy will prevent morbidity and enable resumption of potentially life‐extending oncologic therapy. Additional pharmacovigilance and further study are necessary to better clarify the incidence, pathogenesis, and treatment of this new complication.

Chronic exposure of hairless mice to ultraviolet light (UVB 290-320 nm) causes degradative changes in the dermal matrix and wrinkle production. We compared the effects of two different UVB dosing regimens on wrinkle production and dermal damage in female Skh:HR-1 hairless mice using a bank of unfiltered FS-40 lamps. One group of mice, the low dose group, was exposed to a sub-erythemal UVB dose of 12 mJ/cm2 (1 MED = 14 mJ/cm2), 3 times per week for 20 weeks (total dose = 0.72 J/cm2). A second group, the high dose group, was exposed also 3 times per week for 15 weeks to a UVB dose which started with the sub-erythemal dose of 12 mJ/cm2 at Week 1, and 1 MED at week 2. The dose was then increased weekly by 1 MED until reaching 4 MED at week 5. The animals were then dosed at 4 MED for 10 additional weeks (total dose = 2.1 J/cm2). Visual results indicate that, as expected, within the same group, the degree of wrinkling was generally dependent on the total UVB dose administered. However, comparison between the low dose and high dose groups shows that equal cumulative UVB doses did not always result in identical wrinkle grades. For example, at a cumulative dose of 0.5 J/cm2, the mean wrinkle grade for the low dose group was 1.75 compared to that of 1.2 for the high dose group (age-matched = 0). This observation may suggest that there are other factors in addition to total cumulative dose which are important for the appearance of wrinkling in this model.

To explore the feasibility of using low-dose computed tomography (CT) guidance in the process of radiofrequency ablation (RFA) for the treatment of liver tumours. In this study, 150 patients requiring CT-guided RFA for liver tumours were divided into conventional-dose (250 mA, n = 75) and low-dose (50 mA, n = 75) groups based on the guided CT dose. Image quality and radiation dose were compared between the two groups. The CT images of both groups met the requirements for RFA treatment, and the treatment was successfully completed. The radiation dose parameters in the conventional-dose group were a volume CT dose index of 19.14 ± 7.16 mGy, a dose-length product of 4,987.19 ± 1,679.80 mGy·cm and an effective dose (ED) of 74.81 ± 28.20 mSv. The ED in the low-dose group was 74.8% lower than that in the conventional-dose group (p < 0.05). The CT images of both groups met the requirements for RFA treatment, with the low-dose group exhibiting lower image quality but clear visualisation of the radiofrequency electrode needle in the liver tumours. At the 1–3-month follow-up, the complete ablation rates were comparable between the low-dose (78.86%) and conventional-dose (79.12%) groups (p > 0.05), demonstrating short-term technical success. Low-dose CT protocols for guiding RFA may reduce the radiation dose without compromising oncologic outcomes. However, these findings should be interpreted in the context of the short-term (1–3 months) follow-up period, which assessed immediate ablation success but not long-term recurrence rates. Not applicable.

To find a threshold body weight (BW) below 100 kg above which computed tomography pulmonary angiography (CTPA) using reduced radiation and a reduced contrast material (CM) dose provides significantly impaired quality and diagnostic confidence compared with standard-dose CTPA. In this prospectively randomised study of 501 patients with suspected pulmonary embolism and BW <100 kg, 246 were allocated into the low-dose group (80 kVp, 75 ml CM) and 255 into the normal-dose group (100 kVp, 100 ml CM). Contrast-to-noise ratio (CNR) in the pulmonary trunk was calculated. Two blinded chest radiologists independently evaluated subjective image quality and diagnostic confidence. Data were compared between the normal-dose and low-dose groups in five BW subgroups. Vessel attenuation did not differ between the normal-dose and low-dose groups within each BW subgroup (P = 1.0). The CNR was higher with the normal-dose compared with the low-dose protocol (P < 0.006) in all BW subgroups except for the 90-99 kg subgroup (P = 0.812). Subjective image quality and diagnostic confidence did not differ between CT protocols in all subgroups (P between 0.960 and 1.0). Subjective image quality and diagnostic confidence with 80 kVp CTPA is not different from normal-dose protocol in any BW group up to 100 kg. • 80 kVp CTPA is safe in patients weighing <100 kg • Reduced radiation and iodine dose still provide high vessel attenuation • Image quality and diagnostic confidence with low-dose CTPA is good • Diagnostic confidence does not deteriorate in obese patients weighing <100 kg.

BackgroundThe transradial approach for endovascular angiography and interventional procedures is superior to the traditional transfemoral approach in several metrics, including lower access-site complication rates, higher patient satisfaction, and lower hospital...

Background and purposeAccess-site complications constitute a substantial portion of the morbidity associated with transfemoral cerebral angiography, yet no standardized protocol exists for femoral closure and practice patterns vary widely. The...

During diagnostic cerebral angiography, the contrast bolus injected into a vessel can cause substantial changes in baseline pressures and flows. One potential, and serious complication is the re-rupture of aneurysms due to these injections. The goals of this in vitro study were to evaluate the effect of injection conditions on intraneurysmal pressure changes during angiography. A silicone replica of a complete circle of Willis model with ophthalmic, anterior communicating, and basilar tip aneurysms was connected to a physiologically accurate flow pump. Contrast injections were performed under different conditions (carotid or vertebral vessel imaging, catheter diameter, injection rate, injection time, and arterial blood flow rate) and the pressure in each aneurysm was recorded before and during each injection. The effect of injection conditions on percentage increase in aneurysm pressures was statistically assessed. Additionally, the effect of the distance between the aneurysm and the catheter-tip on aneurysmal pressures was assessed. Mean intraneurysmal pressures during injection (84.5 ± 10.8 mmHg) were significantly higher than pre-injection pressures (80.4 ± 10.6 mmHg, p < 0.0001). Only 3 of the 5 conditions - carotid injections, higher injection rates, and smaller catheter diameters - significantly increased intraneurysmal pressures. The catheter-tip distance showed no correlation to pressure increases. Increasing contrast injection rates and decreasing catheter diameters are correlated to intraneurysmal pressure increases during angiography irrespective of the distance to the catheter tip. Future in vivo studies are required to confirm these findings and determine whether the amplitude of pressure increases with commonly used injection rates can be clinically detrimental.