Feasibility of low-dose digital subtraction angiography protocols for the endovascular treatment of intracranial dural arteriovenous fistulas.

BACKGROUND: Among neurointerventional procedures, the embolization of complex shunt lesions usually requires more radiation dose. We aimed to evaluate the procedural outcome and safety in using low-dose DSA protocols for intracranial dural arteriovenous fistula (AVF) embolization treatment. METHODS: Between January 2014 and July 2018, 55 patients with dural AVFs who underwent endovascular treatment were included in the study. The low-dose group (n = 27) included from January 2016 used various low-dose DSA protocols made by modifying the thickness of the copper filter or the detector entrance dose. We compared radiation dose metrics, such as air-kerma, kerma-air product (KAP), and fluoroscopy time, as well as clinical and imaging outcomes with the conventional-dose group (n = 28) included before January 2016. RESULTS: The total KAP was 40.1% lower in the low-dose group (87.9 vs. 146.7 Gy cm2, p = 0.002). The average number of DSA runs (25.1 vs. 25.5, p = 0.86) and fluoroscopy times (77.4 vs. 69.7 min, p = 0.48) were similar between the groups. An immediate favorable occlusion rate (total or near total occlusion) was achieved in 41 (74.5%) patients. Ten patients (18.2%) underwent additional procedures due to residual (n = 6) and/or recurrent (n = 5) lesions. At a median of 10 months follow-up, 45 patients (86.5%) had achieved favorable occlusion. Treatment outcomes showed no significant between-group differences. There was one case (1.8%) of procedure-related complications in the low-dose group. All but one patient showed favorable clinical outcomes (modified Rankin score ≤ 2). CONCLUSION: The low-dose protocols were feasible by showing significant radiation dose reduction and acceptable procedural outcome.

Low-Dose Fluoroscopy Protocol for Diagnostic Cerebral Angiography.

PURPOSE: We applied a low-dose fluoroscopic protocol in routine diagnostic cerebral angiography and evaluated the feasibility of the protocol. MATERIALS AND METHODS: We retrospectively reviewed a total of 60 patients who underwent diagnostic cerebral angiography for various neurovascular diseases from September to November 2019. Routine protocols were used for patients in the first phase and low-dose protocols in the second phase. We compared radiation dose, fluoroscopy time, and complications between groups. RESULTS: Age, diseases, and operators were not significantly different between the two groups. The mean fluoroscopy dose significantly decreased by 52% in the low-dose group (3.09 vs. 6.38 Gy·cm2 ); however, the total dose was not significantly different between the two groups (34.07 vs. 33.70 Gy·cm2 ). The total fluoroscopic time was slightly longer in the low-dose group, but the difference was not statistically significant (12.2. vs. 12.5 minutes). In all patients, angiography was successfully performed without complications. CONCLUSION: The low-dose fluoroscopy protocol is feasible to apply for diagnostic cerebral angiography in that this protocol could significantly reduce the fluoroscopic dose.

Safety and Effectiveness of Percutaneous Low-Dose Thrombin Injection for Femoral Puncture Site Pseudoaneurysms in Neurointervention: Single-Center Experience.

PURPOSE: We present ultrasound-guided percutaneous low-dose thrombin (200-250 IU) injection for the treatment of iatrogenic femoral pseudoaneurysms. Second, we compared patient and procedure factors between subcutaneous hematoma and pseudoaneurysm groups. MATERIALS AND METHODS: From April 2012 to May 2018, 8425 patients underwent neurointervention. Among these patients, 18 had small subcutaneous hematomas and 6 had pseudoaneurysms. Pseudoaneurysms in the neck and entire sac were visualized, and low-dose thrombins were injected while visualizing a "whirlpool" hyperechoic core in the pseudoaneurysm sac. Subcutaneous hematomas were treated with simple compression. We compared the following parameters between the subcutaneous hematoma group and pseudoaneurysm group: sex, age, body mass index (BMI), type of procedure, heparin usage, sheath size, procedure time, and number of previous neurointervention procedures with the Mann-Whitney U test. RESULTS: Most of the pseudoaneurysms were successfully occluded with 200 IU of thrombin (n=5). Only 1 pseudoaneurysm required a slightly higher thrombin concentration (250 IU, n=1). During the short-term follow-up, no residual sac was observed and no surgical repair was necessary. Pain in the groin region was alleviated. During the 1-month follow-up, no evidence of pseudoaneurysm recurrence nor subcutaneous hematoma was noted. Patient factors (sex, age, and BMI) and procedure factors (heparin usage, sheath size, procedure time, number of previous procedures) were not statistically different between the subcutaneous hematoma and pseudoaneurysm groups. CONCLUSION: Ultrasound-guided percutaneous low-dose thrombin injection (200-250 IU) is safe, effective, and less invasive for treating iatrogenic femoral pseudoaneurysm in neurointervention.

Estimated radiation dose according to the craniocaudal angle in cerebral digital subtraction angiography: Patient and phantom study.

BACKGROUND AND PURPOSE: Routine use of cranial angulation with 15-20 degrees, craniocaudal angled (CC) view, for cerebral digital subtraction angiography (DSA) helps minimize bone subtraction artifacts with less overlapping of the vessels, however, it may increase the radiation dose. We designed the phantom and patient studies to determine the effect of the angulation to the radiation dose and the feasibility of true posteroanterior angled (PA) view, in cerebral DSA. MATERIALS AND METHODS: In the phantom study, frontal DSA was simulated with variable angulations. In the patient study with thirty-one subjects, one internal carotid arteriogram was obtained with the CC view and the other, PA view in every patient. The dose-area product (DAP) and reference air-kerma (AK) were measured and compared between the angles. A qualitative analysis was performed to assess the diagnostic performance of the DSA over the angles. RESULTS: The phantom study confirmed that the greater craniocaudal angles caused higher radiation exposure. Especially, the radiation dose (AK) of the CC view was 5.4% higher than that of the PA view. In the patient study, the radiation dose of the PA view was significantly lower compared to the CC view (1.44 vs. 1.63 mGy, AK). In 4 patients, the dose particularly jumped when applying the CC view as the copper filter was automatically removed. The diagnostic ability of the DSA with the PA view tended to be higher without significance. CONCLUSIONS: In a daily routine cerebral angiography, a simple modification of the angle may help to minimize the radiation dose.

Determination of malignant and invasive predictors in branch duct type intraductal papillary mucinous neoplasms of the pancreas: a suggested scoring formula.

Prediction of malignancy or invasiveness of branch duct type intraductal papillary mucinous neoplasm (Br-IPMN) is difficult, and proper treatment strategy has not been well established. The authors investigated the characteristics of Br-IPMN and explored its malignancy or invasiveness predicting factors to suggest a scoring formula for predicting pathologic results. From 1994 to 2008, 237 patients who were diagnosed as Br-IPMN at 11 tertiary referral centers in Korea were retrospectively reviewed. The patients' mean age was 63.1 ± 9.2 yr. One hundred ninty-eight (83.5%) patients had nonmalignant IPMN (81 adenoma, 117 borderline atypia), and 39 (16.5%) had malignant IPMN (13 carcinoma in situ, 26 invasive carcinoma). Cyst size and mural nodule were malignancy determining factors by multivariate analysis. Elevated CEA, cyst size and mural nodule were factors determining invasiveness by multivariate analysis. Using the regression coefficient for significant predictors on multivariate analysis, we constructed a malignancy-predicting scoring formula: 22.4 (mural nodule [0 or 1]) + 0.5 (cyst size [mm]). In invasive IPMN, the formula was expressed as invasiveness-predicting score = 36.6 (mural nodule [0 or 1]) + 32.2 (elevated serum CEA [0 or 1]) + 0.6 (cyst size [mm]). Here we present a scoring formula for prediction of malignancy or invasiveness of Br-IPMN which can be used to determine a proper treatment strategy.