Computed Tomography Angiography Subtraction Research Articles

Diagnostic performance of computed tomography-digital subtraction angiography and conventional magnetic resonance imaging for evaluating the vascularity of osseous spinal tumors

Background and purposePatients with hypervascular spinal tumors may have severe blood loss during tumor resection, which increases the risks of perioperative morbidity and mortality. However, the preoperative evaluation of tumor vascularity may be challenging; moreover, the reliability of the data obtained in conventional preoperative noninvasive imaging is debatable. In this study, we compared conventional magnetic resonance imaging (MRI) and subtraction computed tomography angiography (CTA) in terms of their performance in vascularity evaluation. The catheter digital subtraction angiography (DSA) technique was used as a reference standard. MethodsThis study included 123 consecutive patients with spinal tumor who underwent subtraction CTA, catheter DSA, and subsequent surgery between October 2015 and October 2021. Data regarding qualitative and semiquantitative subtraction CTA parameters and conventional MRI signs were collected for comparison with tumor vascularity graded through catheter DSA. The diagnostic performance of qualitative CTA, quantitative CTA, and conventional MRI in assessing spinal tumor vascularity was analyzed. ResultsQualitative subtraction CTA was the best noninvasive imaging modality in terms of diagnostic performance (area under the receiver operating characteristic curve [AUROC], 0.95). Quantitative CTA was relatively inferior (AUROC, 0.87). MRI results had low reliability (AUROC, 0.51 to 0.59). Intratumoral hemorrhage and prominent foraminal venous plexus were found to be the specific signs for hypervascularity (specificity 93.2%). ConclusionsQualitative subtraction CTA offers the highest diagnostic value in evaluating spinal tumor vascularity, compared to quantitative CTA and MRI. Although conventional MRI may not be a reliable approach, certain MRI signs may have high specificity, which may be crucial for assessing spinal tumor vascularity.

Clinical Study of Symptomatic Nonacute Intracranial Large Arterial Occlusion with Endovascular Recanalization

Abstract Objectives This study reported a single-center clinical trial of endovascular treatment for symptomatic nonacute occlusion of the intracranial large artery (NA-ILAO). The aim of this study was to evaluate the safety, feasibility, and clinical effect of simple balloon dilatation and stent implantation. Methods The patients diagnosed with symptomatic NA-ILAO were enrolled. A total of 40 cases were included in this study. While recanalization failed in 4 patients, it was successful in 36 patients, who were then divided into two groups for further analysis: balloon dilatation group (n = 24) and stent implantation group (n = 12). The perioperative complications, clinical outcome, and follow-up results were analyzed. Results Perioperative complications in the stent implantation group were significantly higher than those in the simple balloon dilatation group (p < 0.05). There were 21 and 10 cases of 90-day good clinical outcome (modified Rankin scale [mRS] ≤ 2) in the balloon and stent groups, respectively (p = 0.518). All patients with successful recanalization underwent digital subtraction angiography (DSA) or CT angiography (CTA) during an average follow-up of 14 months. There were two cases of restenosis in the balloon dilatation group and one in the stent implantation group (p = 1.000). There were two cases of re-occlusion in the stent group and none in the balloon dilatation group (p < 0.001). Stroke recurred in two cases in the stent group and in one case in the simple balloon dilatation group (p = 0.013). Conclusion Endovascular recanalization is safe and feasible for patients with symptomatic NA-ILAO. Compared with stent implantation, simple balloon dilation may be a better recanalization method, but larger randomized controlled trials are needed to confirm it.

COVID-19 pneumonia: Perfusion abnormalities shown on subtraction CT angiography in apparently well-ventilated lungs. A prospective cohort study

PurposeTo evaluate whether a subtraction CT angiography (sCTA) perfusion score may have prognostic value in patients with COVID-19 pneumonia. MethodThis prospective cohort study included adult patients with RT-PCR-confirmed SARS-CoV-2 infection admitted to the ED and a sCTA performed within 24 h of admission between June and September 2020. Perfusion abnormalities (PA) in areas of apparently spared lung parenchyma on conventional CT images were assessed with sCTA perfusion score. Airspace disease extension was assessed with CT severity scores, which were then correlated with clinical outcomes (admission to ICU, requirement of IMV, and death). Inter-rater reliability (IRR) was assessed using Cohen's Kappa. Independent predictors of adverse outcomes were evaluated by multivariable logistic regression analyses using the Hosmer and Lemeshow's test. Results191 patients were included: 112 males (58%), median age of 60.8 years (SD ± 16.0). The IRR was very high (median Kappa statistic: 0.95). No association was found between perfusion CT scores and D-dimer levels (Kendall's Tau-B coefficient = 0.08, p = 0.16) or between PaO2/FiO2 ratios and D-dimer levels (Kendall's Tau-B coefficient = −0.10, p = 0.07). Multivariate analyses adjusting for parenchymal disease extension, vascular beaded appearance, pulmonary embolism, sex, and age showed that severe PA remained a significant predictor for ICU admission (AOR: 6.25, 95% CI 2.10–18.7, p = 0.001). The overall diagnostic capacity of this model was adequate (ROC AUC: 0.83; 95% CI 0.77–0.89). ConclusionsThe assessment of pulmonary perfusion abnormalities in areas of apparently spared lung parenchyma on conventional CT images via sCTA perfusion scoring has prognostic value in COVID-19 pneumonia.

Verification of blood flow path reconstruction mechanism in distal sigmoid colon and rectal cancer after high IMA ligation through preoperative and postoperative comparison by manual subtraction CTA

IntroductionWe aimed to investigate manual subtraction computed tomography angiography (MS-CTA) to further confirm the distribution and classification of LCA (left colic artery) ascending/descending branches, then observe the postoperative blood flow path to illustrate how the above branches evolved to postoperative blood path. Material and methods89 patients with distal sigmoid and rectal cancer were referred in our observation and underwent MS-CTA between June 2020 and March 2022. We classified the distribution of LCA and confirmed whether there exists AMCA (accessory middle colic artery). Then we planned blood flow path based on the classification of LCA branches before operation. High ligation was applied in regular radical surgery. During operation, we carefully protect the bifurcation of ascending and descending LCA. Then we compared the planned blood flow path with the actual postoperative blood flow path to verify the mechanism we proposed previously. ResultsOf 89 patients, 82 cases met our criteria, we summarized 6 distribution pattens of LCA ascending and descending branches. These preoperative pattens are consistent with the inspection during operation. The postoperative blood flow path of 6 pattens is evolved from the above adjacent anastomotic branches and is consistent with the planned blood flow path. We also found 2 cases with IMA stenosis and 1 case with SMA stenosis under pathological condition, and their compensatory blood flow path is in accordance with our theory. The rate of the anastomotic leakage in our study group is relatively low (7.3%). ConclusionMS-CTA could confirm the distribution of LCA and AMCA, display accurate postoperative blood reconstruction path after IMA high ligation, and it further verified the mechanism we proposed previously, which is the proximal anastomotic branches forming new blood flow path from high-pressure area to the low-pressure area. This mechanism might be helpful for performing accurate laparoscopic sigmoid and rectal cancer surgery.

Comparison of bone subtraction CT angiography with standard CT angiography for evaluating circle of Willis in normal dogs.

Bone subtraction computed tomography angiography (BSCTA) is a useful alternative technique for improving visualization of vessels surrounded by skull bone. However, no studies have compared computed tomography angiography (CTA) and BSCTA for improving the visibility of canine cerebral blood vessels. To evaluate the potential benefit of BSCTA for better delineation of brain arteries of the circle of Willis (CoW) in dogs by comparing BSCTA with non-subtraction computed tomography angiography (NSCTA). Brain CTA was performed for nine healthy beagle dogs using a bolus tracking method with saline flushing. A total dose of 600 mgI/kg of contrast agent with an iodine content of 370 mgI/mL was injected at a rate of 4 ml/s. Bone removal was achieved automatically by subtracting non-enhanced computed tomography (CT) data from contrast CT data. Five main intracranial arteries of the CoW were analyzed and graded on a scale of five for qualitative evaluation. Scores of basilar artery, middle cerebral artery, and rostral cerebral artery in the BSCTA group were significantly higher than those in the NSCTA group (p = 0.001, p = 0.020, and p < 0.0001, respectively). Scores of rostral cerebellar artery (RcA) and caudal cerebral artery (CCA) did not differ significantly between the two groups. However, scores of RcA and CCA in the BSCTA group were higher than those in the NSCTA group. BSCTA improved visualization of intracranial arteries of the CoW with close contact to bone. Thus, it should be recommended as a routine scan method in dogs suspected of having brain vessel disease.

Comparison of Lower Extremity Computed Tomography Angiography by Using Different Subtraction Techniques

To compare the diagnostic capabilities of orbital synchronized helical scanning at lower extremity computed tomography angiography between the Add/Sub software and the deformable image registration. From March 2015 to December 2016, 100 dialysis patients underwent orbital synchronized lower limb CT subtraction angiography and lower limb endovascular treatment within 4 months. For the visual evaluation of blood vessels in the lower extremities, a stenosis rate of 50% or more was considered to be stenosis. It was classified into two areas: above-knee (AK) region (superficial femoral artery and popliteal artery) and below-knee (BK) region (anterior tibial artery, posterior tibial artery, and fibula artery). Considering angiography for the lower limb endovascular treatment as the golden standard, we calculated the sensitivity, specificity, positive-predictive value, negative-predictive value, and diagnostic capabilities. Receiver operating characteristic curve (ROC) analysis was performed to calculate the area under curve (AUC). Calcification subtraction failure was observed to be 11% in the AK region and 2% in the BK region using the Add/Sub software. The specificity, positive-predictive value, diagnostic capabilities, and AUC of the deformable image registration were lower than those of the Add/Sub software. Add/Sub software and deformable image registration have high diagnostic capability to remove calcification. On the other hand, the specificity and AUC of the deformable image registration were lower than those of the Add/Sub software. Also, even if the same deformable image registration is used, caution is required because the diagnostic performance varies depending on the site.

Protocol and Preliminary Results of the Establishment of Intracranial Aneurysm Database for Artificial Intelligence Application Based on CTA Images.

Background and PurposeUnruptured intracranial aneurysms (UIAs) are increasingly being detected in clinical practice. Artificial intelligence (AI) has been increasingly used to assist diagnostic techniques and shows encouraging prospects. In this study, we reported the protocol and preliminary results of the establishment of an intracranial aneurysm database for AI application based on computed tomography angiography (CTA) images.MethodsThrough a review of picture archiving and communication systems, we collected CTA images of patients with aneurysms between January 2010 and March 2021. The radiologists performed manual segmentation of all diagnosed aneurysms on subtraction CTA as the basis for automatic aneurysm segmentation. Then, AI will be applied to two stages of aneurysm treatment, namely, automatic aneurysm detection and segmentation model based on the CTA image and the aneurysm risk prediction model.ResultsThree medical centers have been included in this study so far. A total of 3,190 cases of CTA examinations with 4,124 aneurysms were included in the database. All identified aneurysms from CTA images that enrolled in this study were manually segmented on subtraction CTA by six readers. We developed a structure of 3D-Unet for aneurysm detection and segmentation in CTA images. The algorithm was developed and tested using a total of 2,272 head CTAs with 2,938 intracranial aneurysms. The recall and false positives per case (FP/case) of this model for detecting aneurysms were 0.964 and 2.01, and the Dice values for aneurysm segmentation were 0.783.ConclusionThis study introduces the protocol and preliminary results of the establishment of the intracranial aneurysm database for AI applications based on CTA images. The establishment of a multicenter database based on CTA images of intracranial aneurysms is the basis for the application of AI in the diagnosis and treatment of aneurysms. In addition to segmentation, AI should have great potential for aneurysm treatment and management in the future.

Multiple predictors of in-stent restenosis after stent implantation in symptomatic intracranial atherosclerotic stenosis.

This study aimed to identify predictors of intracranial in-stent restenosis (ISR) after stent placement in symptomatic intracranial atherosclerotic stenosis (ICAS). The authors retrospectively collected data from consecutive patients who suffered from symptomatic ICAS and underwent successful stent placement in Beijing Tiantan hospital. Eligible patients were classified into "ISR," "indeterminate ISR," or "no-ISR" groups by follow-up digital subtraction angiography or CT angiography. A multivariate logistic regression model was used to explore the predictors of intracranial ISR after adjustments for age and sex. In addition, ISR and no-ISR patients were divided into two groups based on the strongest predictor, and the incidence of ISR, recurrent stroke, and symptomatic ISR was compared between the two groups. A total of 511 eligible patients were included in the study: 80 ISR, 232 indeterminate ISR, and 199 no-ISR patients. Elevated high-sensitivity C-reactive protein (hs-CRP; odds ratio [OR] 4.747, 95% confidence interval [CI] 2.253-10.01, p < 0.001), Mori type B and C (Mori type B vs Mori type A, OR 3.119, 95% CI 1.093-8.896, p = 0.033; Mori type C vs Mori type A, OR 4.780, 95% CI 1.244-18.37, p = 0.023), coronary artery disease (CAD; OR 2.721, 95% CI 1.192-6.212, p = 0.017), neutrophil/lymphocyte ratio (NLR; OR 1.474 95% CI 1.064-2.042, p = 0.020), residual stenosis (OR 1.050, 95% CI 1.022-1.080, p = 0.001) and concurrent intracranial tandem stenosis (OR 2.276, 95% CI 1.039-4.986, p = 0.040) synergistically contributed to the occurrence of intracranial ISR. Elevated hs-CRP (hs-CRP ≥ 3 mg/L) was the strongest predictor for ISR, and the incidence of ISR in the elevated hs-CRP group and normal hs-CRP group (hs-CRP < 3 mg/L) was 57.14% versus 21.52%, respectively, with recurrent stroke 44.64% versus 16.59%, and symptomatic ISR 41.07% versus 8.52%. Elevated hs-CRP level, NLR, residual stenosis, Mori type B and C, CAD, and concurrent intracranial tandem stenosis are the main predictors of intracranial ISR, and elevated hs-CRP is crucially associated with recurrent stroke in patients with symptomatic ICAS after intracranial stent implantation.

Factors Distinguishing Proximal and Distal Internal Carotid Artery Occlusions in Patients with Acute Ischemic Stroke.

Acute internal carotid artery (ICA) occlusions cause extensive brain ischemia. Accurate determination of the occlusion site facilitates rapid revascularization interventions and improves prognosis. However, proximal ICA occlusions, as determined with computed tomography (CT) angiography, often are located more distally. Therefore, we assessed clinical and imaging factors associated with the accurate determination of occlusion sites. In this observational study, we evaluated 102 patients who presented acute ischemic stroke symptoms and had a CT angiography within 6 h, showing proximal ICA occlusion. The participants were divided into two groups, depending on whether there was correspondence between digital subtraction angiography and CT angiography regarding the occlusion location. Proximal occlusions were, accordingly, categorized as “true” (correspondence) or “false” (no correspondence; distal). Demographic, clinical, and imaging features were analyzed. Multivariate regression analysis was performed to identify factors predicting the correspondence between actual ICA occlusion sites and those detected by CT angiography. The shape (Odds ratios, OR = 646.584; Confidence interval, CI = 21.703–19263.187; p < 0.001) and the length (OR = 0.696; CI = 0.535–0.904; p = 0.007) of the ICA occlusion and atrial fibrillation (OR = 0.024; CI = 0.002–0.340; p = 0.006) were significant factors. The cut-off length of ICA stump at 6.2 mm, the sensitivity was 71%, and the specificity was 70% (area under the ROC curve = 0.767).

Artificial Intelligence Segmentation Model-Based Computed Tomography Angiography Image in the Diagnosis of Congenital Aortic Constriction

This study was to analyze the impacts of the image segmentation model and computed tomography angiography (CTA) on the clinical diagnosis of aortic constriction under the background of artificial intelligence. In this study, 126 patients with congenital aortic constriction (CAC) diagnosed by surgery were selected as the research objects and routine digital subtraction angiography (DSA) and CTA were performed. Then, the traditional active contour model (AC model) was optimized based on the local area information to construct a new image segmentation model for intelligent segmentation and reconstruction of the CTA images of patients. The results revealed that compared with the AC model and the image segmentation model based on region growth (RG model) obtained from angiography segmentation, the algorithm constructed in this study showed a smaller segmentation range for angiography images and more accurate segmentation results. The quantitative data results suggested that the evolution times and running time of the constructed model were less than those of the AC and RG models P &lt; 0.05 . Based on the gold standard of DSA examination results, there were 122 correctly diagnosed cases, 3 missed diagnosed cases, and 1 misdiagnosed by CTA, so the diagnosis coincidence rate was 96.83%. Compared with DSA, the average inner diameter and average pressure difference of patients with precatheter, paracatheter, and postcatheter type were not greatly different in CTA P &gt; 0.05 . The CTA examination suggested there were 154 cases with intracardiac structural abnormalities, with a detection rate of 86.52%; there were 32 cases of cardiac-vascular connection abnormalities, with a detection rate of 100%; and there were 79 extracardiac vascular abnormalities, with the detection rate of 95.18%. It indicated that the optimized image segmentation model based on local area information proposed in this paper has excellent segmentation performance for CT angiography images and has good segmentation effect and efficiency. The CTA based on the artificial intelligence image segmentation model showed a better diagnostic effect on abnormal heart-vascular connection and abnormal extracardiac blood vessels and can be used as an effective examination method for clinical diagnosis of CAC.

Artificial Intelligence Algorithm-Based CTA Imaging for Diagnosing Ischemic Type Biliary Lesions after Orthotopic Liver Transplantation.

The study focused on the clinical application value of artificial intelligence-based computed tomography angiography (CTA) in the diagnosis of orthotopic liver transplantation (OLT) after ischemic type biliary lesions (ITBL). A total of 66 patients receiving OLT in hospital were selected. Convolutional neural network (CNN) algorithm was used to denoise and detect the edges of CTA images of patients. At the same time, the quality of the processed image was subjectively evaluated and quantified by Hmax, Ur, Cr, and other indicators. Then, the digital subtraction angiography (DSA) diagnosis and CTA diagnosis based on CNN were compared for the sensitivity, specificity, positive predictive value, negative predictive value, and patient classification results. It was found that CTA can clearly reflect the information of hepatic aorta lesions and thrombosis in patients with ischemic single-duct injury after liver transplantation. After neural network algorithm processing, the image quality is obviously improved, the lesions are more prominent, and the details of lesion parts are also well displayed. ITBL occurred in 40 (71%) of 56 patients with abnormal CTA at early stage. ITBL occurred in only 8 (12.3%) of 65 patients with normal CTA at early stage. Early CTA manifestations had high sensitivity (72.22%), specificity (87.44%), positive predictive value (60.94%), and negative predictive value (92.06%) for the diagnosis of ITBL. It was concluded that artificial intelligence-based CTA had high clinical application value in the diagnosis of ITBL after OLT.

Sildenafil for treating patients with COVID-19 and perfusion mismatch: a pilot randomized trial

BackgroundSARS-CoV-2 seems to affect the regulation of pulmonary perfusion. Hypoperfusion in areas of well-aerated lung parenchyma results in a ventilation–perfusion mismatch that can be characterized using subtraction computed tomography angiography (sCTA). This study aims to evaluate the efficacy of oral sildenafil in treating COVID-19 inpatients showing perfusion abnormalities in sCTA.MethodsTriple-blinded, randomized, placebo-controlled trial was conducted in Chile in a tertiary-care hospital able to provide on-site sCTA scans and ventilatory support when needed between August 2020 and March 2021. In total, 82 eligible adults were admitted to the ED with RT-PCR-confirmed or highly probable SARS-COV-2 infection and sCTA performed within 24 h of admission showing perfusion abnormalities in areas of well-aerated lung parenchyma; 42 were excluded and 40 participants were enrolled and randomized (1:1 ratio) once hospitalized. The active intervention group received sildenafil (25 mg orally three times a day for seven days), and the control group received identical placebo capsules in the same way. Primary outcomes were differences in oxygenation parameters measured daily during follow-up (PaO2/FiO2 ratio and A-a gradient). Secondary outcomes included admission to the ICU, requirement of non-invasive ventilation, invasive mechanical ventilation (IMV), and mortality rates. Analysis was performed on an intention-to-treat basis.ResultsTotally, 40 participants were enrolled (20 in the placebo group and 20 in the sildenafil group); 33 [82.5%] were male; and median age was 57 [IQR 41–68] years. No significant differences in mean PaO2/FiO2 ratios and A-a gradients were found between groups (repeated-measures ANOVA p = 0.67 and p = 0.69). IMV was required in 4 patients who received placebo and none in the sildenafil arm (logrank p = 0.04). Patients in the sildenafil arm showed a significantly shorter median length of hospital stay than the placebo group (9 IQR 7–12 days vs. 12 IQR 9–21 days, p = 0.04).ConclusionsNo statistically significant differences were found in the oxygenation parameters. Sildenafil treatment could have a potential therapeutic role regarding the need for IMV in COVID-19 patients with specific perfusion patterns in sCTA. A large-scale study is needed to confirm these results.Trial Registration: Sildenafil for treating patients with COVID-19 and perfusion mismatch: a pilot randomized trial, NCT04489446, Registered 28 July 2020, https://clinicaltrials.gov/ct2/show/NCT04489446.

Radiation-Free Thoracic Endovascular Aneurysm Repair with Fiberoptic and Electromagnetic Guidance: A Phantom Study

PurposeTo evaluate the feasibility and accuracy of a radiation-free implantation of a thoracic aortic stent graft employing fiberoptic and electromagnetic tracking in an anthropomorphic phantom. Materials and MethodsAn anthropomorphic phantom was manufactured based on computed tomography (CT) angiography data from a patient. An aortic stent graft application system was equipped with a fiber Bragg gratings and 3 electromagnetic sensors. The stent graft was navigated in the phantom by 3 interventionalists using the tracking data generated by both technologies. One implantation procedure was performed. The technical success of the procedure was evaluated using digital subtraction angiography and CT angiography (before and after the intervention). Tracking accuracy was determined at various anatomical landmarks based on separately acquired fluoroscopic images. The mean/maximum errors were measured for the stent graft application system and the tip/end of the stent graft. ResultsThe procedure resulted in technical success with a mean error below 3 mm for the entire application system and <2 mm for the position of the tip of the stent graft. Navigation/implantation and handling of the device were rated sufficiently accurate and on par with comparable, routinely used stent graft application systems. ConclusionsThe study demonstrates successful stent graft implantation during a thoracic endovascular aortic repair procedure employing advanced guidance techniques and avoiding fluoroscopic imaging. This is an essential step in facilitating the implantation of stent grafts and reducing the health risks associated with ionizing radiation during endovascular procedures.

Ultrasonic characteristics of carotid webs

This study aimed to retrospectively analyze the ultrasonographic images of 46 cases of carotid web (CW) and summarize their manifestations to reduce the rate of misdiagnosis. For the analysis of ultrasonic manifestations, 46 patients with a confirmed diagnosis of CW by digital subtraction angiography (DSA) and CT angiography (CTA) in our hospital from January 2015 to October 2020 were collected. The location and the morphology of CW, the presence of a plaque at the base and thrombus at the surrounding of the CW, and whether they resulted in arteriostenosis were discussed. The average age of 46 patients was 43.23 ± 4.89years old and there were 18 males and 28 females. Fifteen patients were admitted with cerebral infarction. The CW was located at the initial segment of the internal carotid artery in 22 cases, the bifurcation of the carotid artery in 20 cases, and the common carotid artery in 4 cases. CW in 5 patients was longer than half of the artery diameter, two patients with "cliff-like" arteriostenosis, 29 patients with plaques, and 16 patients with thrombi. The CW grew in the direction of the blood flow without obvious fluttering. The CW has a higher display rate on the ultrasound longitudinal section than the transverse section. We identified some typical ultrasound characteristics of CW. Recognizing them will improve diagnostic accuracy of CW by ultrasonography.

Influence of diabetes on diagnostic performance of computed tomography angiography of the calf arteries in acute limb ischemia.

Patients with diabetes mellitus (DM) have a more extensive distal arterial occlusive disease compared to non-diabetic patients. Diagnostic imaging is a necessity to identify the location and extent of the arterial occlusion in acute limb ischemia (ALI). Computed tomography angiography (CTA) is the most commonly used modality and the diagnostic performance with CTA of calf arteries may be questioned. To evaluate diagnostic performance of CTA of calf arteries in ALI and to compare patients with and without DM. All thrombolytic treatments performed during 2001-2018 in patients with ALI were included. Initial digital subtraction angiography (DSA) and CTA of all patients were classified according to the Inter-Society Consensus for the Management of Peripheral Arterial Disease (TASC II) below-the-knee arteries and compared to CTA. Two raters assessed the CTA images independently. Inter-rater reliability was expressed as intraclass correlation (ICC) with 95% confidence intervals (CI). Patients with (n = 23) and without (n = 85) DM had lower (P = 0.006) glomerular filtration rate. ICC between CTA and DSA was 0.33 (95% CI -0.22 to 0.56) and 0.71 (95% CI 0.38-0.68) in patients with and without DM, respectively. Sensitivity with CTA for TASC D lesions in patients with and without DM was 0.14 (95% CI -0.12 to 0.40) and 0.64 (95% CI 0.48-0.80), respectively. The sensitivity of CTA for assessment of infra-popliteal TASC D lesions in patients with ALI was not acceptable in patients with DM in contrast to those without DM. Another imaging option at present times should be considered for patients with DM.

Computed tomographic angiography may be used for assessing the dilatation of the anterior choroidal and posterior communicating arteries in patients with moyamoya syndrome.

To evaluate the feasibility of CT angiography (CTA) for assessing anterior choroidal artery (AChA) and posterior communicating artery (PComA) dilatation in patients with moyamoya syndrome (MMS). Eighty-eight MMS patients who underwent digital subtraction angiography (DSA) and CTA within 1 month were enrolled. The AChA was graded using both DSA and CTA. Given the features of dual blood supply, DSA was firstly used for grading of the PComA. Then, the calibers of PComA, P1 or P2 segment of the posterior cerebral artery (PCA), were recorded from CTA. Taking DSA as a reference standard, the optimal cutoff values of the PComA/P1 or PComA/P2 were calculated to determine the dilatation of PComA. Both the AChA and PComA were classified as extreme dilatation (ED, grade 2) or non-extreme dilatation (NED, grade 0 or 1). The AChA was evaluated in 149 affected hemispheres of 88 patients while the PComA was evaluated in 70 affected hemispheres of 49 patients. The sensitivity and specificity of CTA in diagnosing AChA-ED were 92% and 93.5% respectively. Both the PComA/P1 (p < 0.001) and PComA/P2 (p = 0.4) ratios were increased in the PComA-ED group with the former yielding a better detecting performance than the latter (AUC = 0.92 vs 0.85, p = 0.046). When using 0.71 as a cutoff value, the sensitivity and specificity of the PComA/P1 ratio for diagnosis of PComA-ED cases were 91.3% and 83.3% respectively. CTA could be used for the AChA classification in MMS patients, while a PComA/P1 ratio greater than 0.71 indicates the existence of PComA-ED. • CTA showed a high sensitivity, specificity, and accuracy in diagnosing AChA-ED in patients with MMS. • PComA/P1 ratio greater than 0.71 on CTA signified an extremely dilated PComA. • CTA could be used to assess the dilatation of AChA and PComA in MMS patients, especially for routine postoperative follow-up.

Application Value of CTA in the Computer-Aided Diagnosis of Subarachnoid Hemorrhage of Different Origins.

Subarachnoid hemorrhage (SAH) is difficult to detect because of its circulation through subarachnoid space, which leads to a high rate of missed diagnosis. Based on the above background, the purpose of this study is to study the application value of brain CT angiography (CTA) in computer-aided diagnosis of subarachnoid hemorrhage with a wide range of brain digital subtraction angiography as a gold standard. This paper collected images and related medical records of 111 patients with spontaneous subarachnoid hemorrhage receiving brain CTA and DSA examinations from February 2015 to November 2019 in the neurology department of our hospital. In contrast to the number, position, length, width, and neck width of the causative aneurysm detected by DSA, we evaluated the diagnostic results of CTA and evaluated whether there was statistical difference between the two detectives of intracranial aneurysms. The results showed that the area under ROC curve of subtraction CTA and conventional CTA was 1.000 and 0.818, respectively, which indicated that the former had better display effect on internal carotid aneurysm (AUC > 0.9), while the latter had medium value (0.7 < AUC ≤ 0.9), and the difference was statistically significant (z = 2.390, p=0.017).

Skull base aneurysms: a retrospective review of fifteen cases focusing on the involvement of internal carotid artery

Objective: To explore the diagnosis and clinical features of internal carotid artery aneurysm in the skull base. Methods: The data of 15 patients with internal carotid aneurysms in the skull base diagnosed and treated by digital subtraction angiography (DSA) or CT angiography (CTA) in the Provincial Hospital Affiliated to Shandong First Medical University from 1995 to 2017 were collected and analyzed. Among the 15 patients, 12 were males, and 3 were females, aging from 17 to 67 years old, with a median age of 44 years. Thirteen patients were diagnosed by DSA; the other two patients were diagnosed by CTA. Thirteen patients were diagnosed with pseudoaneurysm with the first symptom of epistaxis, in which eight patients underwent head trauma and 5 underwent radiotherapy of skull base tumor. The other two patients were diagnosed with true aneurysm presented headache and cranial nerve disorder. All patients were followed up for 2 to 12 years after treatment to see whether they were cured and survived. Results: Among the eight patients with a history of trauma, five patients were cured by embolization, two patients without embolization died of massive epistaxis, one patient died of progressive cerebral infarction after embolization. Among the five patients with radiotherapy of skull base tumor, one patient died of cerebral infarction after embolization, two patients died out of the hospital due to the recurrence of the primary tumor and intracranial invasion, one patient recovered well after embolization and surgical operation, one patient gave up treatment and died of massive hemorrhage out of hospital. In the other two patients with symptom of headache, one received embolization treatment outside the hospital after receiving mistake operation, and another one gave up treatment and died due to personal reasons. In total, four patients died in hospital, four died out of the hospital, and seven patients survived. Conclusions: Internal carotid artery aneurysm is a high-risk disease of anterior and middle skull base. For patients with epistaxis with a history of trauma and radiotherapy or patients with headaches and cranial nerve disorders, the possibility of the internal carotid artery aneurysm should be considered, in which DSA or CTA examination is essentially required for ensured diagnosis and disease evaluation.. The correct diagnosis and treatment by the otolaryngologist are crucial to the prognosis of the patient.

Sildenafil for the Treatment of Patients With COVID-19 and Perfusion Mismatch on Subtraction Computed Tomography Angiography: A Pilot, Placebo-Controlled Randomised Trial

Background: Severe gas exchange impairment can develop even in initial stages of COVID-19 pneumonia. SARS-CoV-2 seems to affect the regulation of pulmonary perfusion, through a renin-angiotensin system imbalance that occurs as a result of the virus binding to ACE2. Hypoperfusion to areas of well-aerated lung parenchyma results in a ventilation-perfusion mismatch that can be characterized using subtraction computed tomography angiography (sCTA). We aimed to investigate the potential efficacy and safety of oral sildenafil in the treatment of inpatients with COVID-19 that showed perfusion abnormalities in sCTA.Methods: This triple-blind, single-centre, placebo-controlled trial, was done at Hospital Naval Almirante Nef, Chile. We enrolled adult patients (>18 years of age) with clinically diagnosed, highly probable or confirmed COVID-19 infection, that were admitted for inpatient treatment, and with a sCTA carried out within 24 hours of admission that showed perfusion abnormalities in areas of well-aerated lung parenchyma. Patients were randomly assigned (1:1) to receive sildenafil (25 mg orally three times a day for seven days) or placebo. The primary endpoint was the change in the ratio between arterial oxygen partial pressure and fractional inspired oxygen (PaO2/FiO2 ratio), and a co-primary endpoint was the change in alveolar-arterial oxygen gradient (A-a gradient), both of which were calculated 1 hour after administration of the intervention on the first day, and on a daily basis during follow-up, using samples from an arterial line in all patients, and analysed using a two-way repeated-measures analysis of variance (ANOVA). Secondary endpoints including intensive care unit admission, the requirement of non-invasive mechanical ventilation or requirement of high-flow nasal cannula, initiation of mechanical ventilation and mortality rates were evaluated using survival analysis with the Kaplan-Meier method and log-rank statistic. The trial is now done. This trial is registered with ClinicalTrials.gov, NCT04489446.Findings: Between August 20, 2020 and March 31, 2021, we recruited 20 patients per group. No statistically significant differences in mean PaO2/FiO2 ratios (repeated measures ANOVA p=0·67) and A-a gradients (repeated measures ANOVA p=0·69) were found between study groups. Invasive mechanical ventilation had to be initiated in four patients, all in the placebo arm, showing a statistically significant difference with the sildenafil arm (logrank p=0·04). Patients allocated to the sildenafil arm also showed a significantly shorter median length of stay in the hospital when compared with the placebo group (9 IQR 7-12 days vs 12 IQR 9-21 days, p=0·04).Interpretation: Sildenafil treatment decreased the need for initiation of invasive mechanical ventilation and reduced the length of stay in the hospital. However, there were no statistically significant differences in the oxygenation parameter (PaO2/FiO2 ratio and A-a gradient). The improvement in clinically relevant outcomes, without significant differences in specific laboratory outcomes, warrants the conduction of larger trials using sildenafil for the treatment of COVID-19 patients with specific perfusion patterns in sCTA.Clinical Trial Registration Details: This trial is registered with ClinicalTrials.gov, NCT04489446.Funding Information: There were no external sources of funding for this investigation.Declaration of Interests: We declare no competing interests.Ethics Approval Statement: The study was approved by the ethics committee of Hospital Naval Almirante Nef, and by the ethics committee of Universidad Andres Bello, Chile. All patients provided written informed consent before randomisation.

Effect of different surgical options for posterior inferior cerebellar artery aneurysms

Objective To explore the clinical effect of various surgical operations on the treatment of posterior inferior cerebellar aneurysm. Methods The clinical data of 36 patients with a total of 36 posterior inferior cerebellar aneurysms admitted to Department of Neurosurgery, Weihai Central Hospital from October 2014 to May 2017 were retrospectively analyzed. Among all 36 patients, 22 underwent transcatheter embolization, 9 underwent aneurysm clipping using craniotomy, and the remaining 5 underwent cerebral artery bypass surgery combined with transcatheter embolization. The treatment outcome was evaluated using Glasgow outcome scale(GOS) at discharge and modified Rankin scale (mRS) at follow-up. Imaging outcome was evaluated by digital subtraction angiography (DSA) or CT angiography (CTA). Results Of the 22 patients undergoing transcatheter embolization, 21 were completely embolized. Aneurysms in 8 of the 9 patients were successfully clipped. Successful vascular anastomosis and complete embolization were achieved in 5 patients undergoing cerebral artery bypass surgery combined with transcatheter embolization. Among the 36 patients, 9 cases developed non-newly developed postoperative neurological deficits and 1 died. Thirty-five patients were discharged with GOS grade Ⅴ in 18 cases, Ⅳ in 14 cases and Ⅲ in 3 cases. Thirty-five cases were reexamined by CTA or DSA at 2 weeks post operation, which indicated disappearance of aneurysm. At follow-up of 3 months to 1 year post operation, 3 cases(8.6%) of aneurysm recurrence were reported which had undergone interventional embolization, and the rest of 32 patients had no recurrence. Thirty-five patients were followed up for 1 year. The mRS score was 0-1 in 21 cases, 2 in 8, 3 in 3, 4 in 1 and 5 in 1 case. The rate of good outcome were 85.3% (29/34) and there was 1 patient lost to follow-up. Conclusions According to the specific condition, interventional embolization, craniotomy of aneurysm clipping, or cerebral artery bypass surgery combined with transcatheter embolization could be performed to treat the posterior inferior cerebellar aneurysm, which might lead to relatively good clinical outcome with low incidence of aneurysm recurrence. Key words: Incranial aneurysm; Embolization, therapeutic; Microsurgery; Treatment outcome; Inferior cerebellar artery