Subsequent Digital Subtraction Angiography Research Articles

Can the second phase of contrast-enhanced MRA of the neck provide additional information in the acute stroke setting?

Double-concentration magnetic resonance imaging (MRI) contrast agents are frequently used in contrast-enhanced MR angiography (CE-MRA) of the head and neck. To avoid mistiming the peak concentration of intraluminal contrast (due to shorter duration of peak), a second acquisition is sometimes performed. To evaluate additional information from the second acquisition of CE-MRA and compare the collateral scoring to the hypoperfusion index obtained on MR perfusion, and to investigate presence of pseudo-occlusion using the second phase of CE-MRA. A retrospective study was conducted. CE-MRA of the brain/neck, dynamic susceptibility contrast (DSC) MR perfusion scan (in majority) and subsequent digital subtraction angiography (DSA) were evaluated in patients with previous acute internal carotid artery (ICA)/middle cerebral artery (MCA) occlusion. Evaluation of CE-MRA/MR perfusion and DSA was performed by three experienced neuroradiologists and one neurointerventionist, respectively. The site of ICA occlusion was seen to be distal to the site noted on early arterial phase (pseudo-occlusion of ICA) in 28.5% of patients. A significant negative correlation was seen between a higher HIR and collateral score. Evaluation of second phase CE-MRA can provide valuable information that may be otherwise lost if only the early arterial phase is evaluated.

Contrast-enhanced ultrasound reveals free-floating thrombus in carotid artery: The cause of stroke is surprisingly plaque rupture.

Acute stroke poses a serious threat to people's health. The occurrence of a thrombus following the rupture of vulnerable plaques in the carotid artery is a significant contributor to the development of stroke. In previous case reports, it has been challenging to visualize tiny ulcerations within carotid artery plaques using computed tomography angiography (CTA) and digital subtraction angiography (DSA), even when the rupture of the plaque leads to the formation of a free-floating thrombus (FFT). However, in this particular case, contrast-enhanced ultrasound (CEUS) was able to overcome this limitation and provide a more precise assessment, confirming that the FFT formation was indeed a result of plaque rupture rather than any other potential causes. Cases that utilize CEUS to visualize the formation of ulcers and FFT resulting from plaque rupture are even more rare. As such, we present this case to shed light on this infrequent phenomenon. In this case study, we present a 65-year-old male patient who was admitted to the hospital due to headache and abnormal mental behavior for one day. During the routine cervical artery ultrasound examination upon admission, we detected the presence of plaque in the right internal carotid artery of the patient, resulting in luminal stenosis. Additionally, we observed suspected hypoechoic material at the distal end of the plaque. After undergoing CEUS examination, it was definitively determined that an ulcer had formed and a FFT had developed due to the rupture of carotid artery plaque. Subsequent CTA and DSA examinations further confirmed the presence of the FFT. The magnetic resonance imaging (MRI) reveals an acute lacunar infarction in the head of the right caput nuclei caudate, which strengthens the potential link between the patient's neurological and psychiatric symptoms observed during admission. The patient received prompt antiplatelet therapy and underwent cervical artery stenting surgery with the assistance of a distal embolic protection device. Following the procedure, the patient was discharged on the fourth day and experienced a complete recovery. CEUS is a valuable tool for visualizing FFT resulting from the rupture of vulnerable plaques in the carotid artery.

Color Duplex Ultrasonography for the Evaluation of Innominate, Subclavian, and Common Carotid Artery Stenosis.

This study aimed to validate the efficiency of Doppler ultrasonography for predicting the innominate, subclavian, and common carotid artery stenosis. This retrospective multicenter study between 2013 and 2022 enrolled 636 patients who underwent carotid Doppler ultrasonography and subsequent digital subtraction angiography. And 58 innominate artery stenosis, 147 common carotid artery stenosis, and 154 subclavian artery stenosis were included. The peak systolic velocity at innominate, subclavian, and common carotid artery, and velocity ratios of innominate artery to common carotid artery, innominate artery to subclavian artery, and common carotid artery to internal carotid artery were measured or calculated. The threshold values were determined using receiver operating characteristic analysis. The threshold values of innominate artery stenosis were peak systolic velocity >206 cm/s (sensitivity: 82.8%; specificity: 91.4%) to predict ≥50% stenosis and >285 cm/s (sensitivity: 89.2%; specificity: 94.9%) to predict ≥70% stenosis. The threshold values of common carotid artery stenosis were peak systolic velocity >175 cm/s (sensitivity: 78.2%; specificity: 91.9%) to predict ≥50% stenosis and >255 cm/s (sensitivity: 87.1%; specificity: 87.2%) to predict ≥70% stenosis. The threshold values of subclavian artery stenosis were peak systolic velocity >200 cm/s (sensitivity: 68.2%; specificity: 84.4%) to predict ≥50% stenosis and >305 cm/s (sensitivity: 57.9%; specificity: 91.4%) to predict ≥70% stenosis. Symptomatic patients with ultrasonic parameters of velocity at innominate artery ≥206 cm/s, velocity at common carotid artery ≥175 cm/s, or velocity at subclavian artery ≥200 cm/s need to be considered for further verification and whether revascularization is necessary.

Photon-Counting Detector CT Angiography Versus Digital Subtraction Angiography in Patients with Peripheral Arterial Disease

Rationale and ObjectivesThis study aims to compare the diagnostic confidence of photon-counting detector CT angiography (PCD-CTA) depending on the used vascular reformatting kernels with digital subtraction angiography (DSA) as diagnostic reference standard in peripheral arterial occlusive disease (PAOD). Material and MethodsIn 39 patients, 45 lower extremity PCD-CTA with subsequent DSA were analyzed. Advanced PAOD (Fontaine stage 4) was ascertained in 77.8% of patients. CTA post-processing comprised three vascular kernels (Bv36/48/56). Objective image quality assessment included vessel attenuation, image noise, contrast-to-noise (CNR) and signal-to-noise ratios (SNR). Subjective evaluation of calcium blooming, vessel sharpness, luminal attenuation and image noise was performed by three radiologists. Diagnostic performance and concordance to DSA were assessed. ResultsThe luminal attenuation remained kernel-independent constant. With sharper kernels, image noise increased substantially, while SNR and CNR decreased. Subjective reduction of calcium blooming and increased vessel sharpness were noted for the sharp Bv56 kernel. While sensitivity in stenosis quantification was comparable between kernels (81.6% vs. 81.5% vs. 81.0%, p=0.797), specificity increased slightly higher sharpness (71.1% vs. 76.9% vs. 79.6%, p=0.067). Diagnostic concordance of stenosis ratings compared to DSA increased likewise (Bv36 vs. Bv56, p=0.002). Severe crural vessel calcifications had no influence on sensitivity, regardless of kernel selection. Contrarily, specificity was substantially worse in severely calcified tibial vessels but could be improved by using the sharp Bv56 kernel (Bv36 vs. Bv56 p=0.024). Diagnostic confidence was highest for Bv56. ConclusionIn lower leg PCD-CTA, sharp convolution kernels increase diagnostic confidence compared to DSA by improved vessel delineation and reduced calcium blooming with acceptable image noise.

Application of simple ultrasound Doppler hemodynamic parameters in the diagnosis of severe renal artery stenosis in routine clinical practice.

Doppler ultrasound (DUS) is recommended in first-line imaging for the diagnosis of renal artery stenosis (RAS). However, the correct selection of Doppler direct or indirect parameters and their optimal thresholds remain controversial. This study explored simple ultrasound Doppler parameters to diagnose severe RAS (RAS ≥70%) in routine clinical practice. In this retrospective study, patients with clinically suspected renovascular hypertension who first underwent renal artery DUS and contrast-enhanced ultrasound (CEUS) and subsequent digital subtraction angiography (DSA) or computed tomography angiography (CTA) were consecutively included. Clinical characteristics and ultrasound Doppler hemodynamic parameters were collected, including peak systolic velocity (PSV), the ratio of the peak velocities in the renal artery and the aorta (RAR), the ratio of the peak velocities in the renal artery and the segmental artery (RSR), and the ratio of the peak velocities in the renal artery and the interlobar artery (RIR). All enrolled patients were divided into two groups based on the degree of diameter reduction: a severe stenosis group (diameter reduction ≥70%) and a non-severe stenosis group (diameter reduction <70%). Logistic regression analysis was performed to determine the independent predictors for severe stenosis. Receiver operating characteristic curves and areas under the curve were used to evaluate the diagnostic performance of the ultrasound Doppler parameters. A total of 85 patients (106 renal arteries) with RAS were included in this study. The optimal thresholds of PSV in the main renal artery and the PSV ratios for diagnosing severe RAS obtained via receiver operating characteristic curves were 249.5 cm/s for PSV, 2.94 for RAR, 5.1 for RSR, and 7.5 for RIR. The areas under the curve of PSV and the ratios all exhibited good diagnostic efficiency (all >0.8). The combination of these four Doppler variables demonstrated a significant benefit to the overall diagnostic value compared with any factor alone [area under the curve (AUC) =0.962; 95% confidence interval (CI): 0.906-0.989; P<0.05]. The combination of PSV and RSR (AUC =0.925; 95% CI: 0.858-0.967) exhibited comparable diagnostic efficiency to the combination of four ultrasonographic variables (z statistic =1.882; P=0.06). This simple and accurate method to evaluate severe RAS based on the velocity obtained via basic DUS may facilitate the detection of severe RAS in the majority of medical institutions and provide a reliable basis for the selection of proper candidates for further angiography or revascularization.

Abstract 101: Ophthalmic Artery Aneurysm Embolization Resulting in Resolution of Headaches and Visual Symptoms

Introduction Cerebral aneurysms are a rare cause of headaches and visual symptoms. Most common locations include anterior communicating artery, internal carotid arteries (ICAs), middle cerebral arteries, and tip of the basilar artery. While most unruptured aneurysms are asymptomatic, when symptoms do occur, they are most often headaches, cranial nerve palsies, or bilateral temporal hemianopsia due to compression of surrounding nerves or the optic chiasm. Rarely, thrombus formation within an aneurysm can lead to symptoms via distal embolization and infarction. The literature is limited regarding repeated aneurysmal microembolism formation or transient alterations in blood flow dynamics leading to episodic symptoms. Methods We report the case of a 55 year‐old woman with Ehlers‐Danlos syndrome and syringomyelia who presented to the hospital with one week of intermittent left eye visual disturbances, characterized by either complete transient monocular vision loss or blurriness lasting for 30 seconds at a time and occurring multiple times per day. These symptoms were also associated with pressure‐like headaches that originated around the left eye and radiated to the left side of her head. Results Neurological and ophthalmological examinations were notable for normal cranial nerve function, including intact visual acuity, visual fields, color vision and extraocular movements in each eye. On a dilated fundoscopic exam, there were no retinal or optic disc abnormalities. The rest of the neurological exam was normal. Head and neck CTA and subsequent digital subtraction angiography (DSA) showed multiple bilateral ICA aneurysms, as well as a 4 millimeter left ophthalmic artery aneurysm. Brain and orbits MRI with contrast showed no acute abnormalities, including no evidence of infarction or intracranial hemorrhage. She was started on clopidogrel due to concern for recurrent retinal transient ischemic attacks as well as escalating doses of nortriptyline for empiric treatment of possible ocular migraines. In follow‐up three months later, she continued to have the same visual and headaches symptoms. She underwent a successful elective flow diversion embolization of the ophthalmic artery aneurysm with subsequent resolution of her symptoms Conclusion Here we describe a case of a patient who presented with episodic monocular vision changes and headaches ipsilateral to an ophthalmic artery aneurysm, who experienced complete resolution of these symptoms following flow diversion embolization of the aneurysm. Although the precise pathophysiological relationship between the aneurysm and her visual symptoms is unclear, potential mechanisms include aneurysmal microthrombus formation with retinal embolization and dissolution, hemodynamic retinal blood flow changes related to the aneurysm, or recurrent ocular migraines triggered by the ophthalmic artery aneurysm.

310 Rare Elusive Cause of Significant Haematuria – Case Series and Review of Literature

Abstract Arterioureteral fistula (AUF) is a direct communication between the ureter and an artery and is a rare cause of catastrophic, life-threatening haematuria. Fistulation may occur between the ureter and the abdominal aorta, common iliac, external and internal iliac and inferior mesenteric arteries and is typically observed in patients with a prior history of pelvic radiotherapy, oncological pelvic surgeries, aortoiliac vascular procedures and pelvic exenteration. As AUF is so rarely encountered in clinical practice, the urologist may fail to appreciate its presence until late in the patient’s presentation. We are presenting case series as well as review of literature. Patient number 1 presented with repeated episodic large volume haematuria in whom the cause of symptoms remained persistently elusive despite repeated imaging. An eventual diagnosis of a secondary right internal iliac - ureteral fistula was ascertained on a subsequent Digital Subtraction Angiography of the renal tract. The fistula was embolised using an endovascular approach. The patient remained stable post emobilisation and was successfully discharged. Patient number 2 presented with haematuria from her ileal conduit. Initially the cause of symptoms was thought to be due to ureteric stents. During change in her stents, brisk bleeding led to further investigation including iliac angiogram confirming bleeding from left common iliac artery. She had covered common iliac artery stent which successfully controlled her bleeding. These cases emphasise the diagnostic difficulty of AUF, outlines the management principles of this rare disease and aims to increase awareness of this rare yet potentially lethal phenomenon amongst practitioners of urology and interventional radiology.

Diagnostic performance of dynamic 3D magnetic resonance angiography in daily practice for the detection of intracranial arteriovenous shunts in patients with non-traumatic intracranial hemorrhage.

Identification of treatable causes of intracranial hemorrhage (ICH) such as intracranial arteriovenous shunt is crucial to prevent recurrence. However, diagnostic approaches vary considerably across centers, partly because of limited knowledge of the diagnostic performance of first-line vascular imaging techniques. We assessed the diagnostic performance of dynamic three-dimensional magnetic resonance angiography (dynamic 3D MRA) in daily practice to detect intracranial arteriovenous shunts in ICH patients against subsequent digital subtraction angiography (DSA) as reference standard. We reviewed all adult patients who underwent first-line dynamic 3D MRA and subsequent DSA for non-traumatic ICH between January 2016 and September 2021 in a tertiary center. Sensitivity, specificity, accuracy, positive and negative predictive values of dynamic 3D MRA for the detection of intracranial arteriovenous shunt were calculated with DSA as reference standard. Among 104 included patients, 29 (27.9%) had a DSA-confirmed arteriovenous shunt [19 pial arteriovenous malformations, 10 dural arteriovenous fistulae; median onset-to-DSA: 17 (IQR: 3-88) days]. The sensitivity and specificity of dynamic 3D MRA [median onset-to-dynamic 3D MRA: 14 (3-101) h] for the detection of intracranial arteriovenous shunt were 66% (95% CI: 48-83) and 91% (95% CI: 84-97), respectively. The corresponding accuracy, positive and negative predictive values were 84% (95% CI: 77-91), 73% (95% CI: 56-90), and 87% (95% CI: 80-95), respectively. This study suggests that although first-line evaluation with dynamic 3D MRA may be helpful for the detection of intracranial arteriovenous shunts in patients with ICH, additional vascular imaging work-up should not be withheld if dynamic 3D MRA is negative. Comparative prospective studies are needed to determine the best imaging strategy to diagnose arteriovenous shunts after non-traumatic ICH.

ASPECT Score and Its Application to Vasospasm in Aneurysmal Subarachnoid Haemorrhage: a Case–Control Study

Delayed cerebral ischaemia (DCI) is a significant complication of aneurysmal subarachnoid haemorrhage (aSAH) and is strongly associated with poorer outcome. The Alberta Stroke Program Early Computer Tomography (ASPECT) score is an established scoring tool, used in acute ischaemic stroke, to quantify early ischaemic changes on CT head scans. We aim to identify if ASPECT scoring correlates with functional outcome in DCI following aSAH. Retrospective case–control study. Inclusion criteria: admission to the Department of Neurosurgery at Leeds Teaching Hospitals NHS Trust (a tertiary neurosurgical centre in the United Kingdom) between 2014 and 2018, with a diagnosis of anterior circulation aneurysmal subarachnoid haemorrhage; as confirmed by initial CT scan and subsequent CT angiography or catheter digital subtraction angiography. Cases were those who developed DCI (n = 43) and controls were randomly selected from those who did not develop DCI (n = 46) but otherwise met the same inclusion criteria. The primary outcome measure was Glasgow Outcome Score (GOS): assessed at discharge and 3 months. ASPECT scores were calculated from non-contrast CT head scans by three researchers blinded to each other and clinical outcome. Spearman’s rank correlation was used to calculate correlation between ASPECT scores and GOS. ASPECT score positively correlated with GOS in the cases both at discharge (Spearman rho 0.436, p = 0.003) and at 3 months (Spearman rho 0.431, p = 0.004). When corrected for Fisher grading, the adjusted odds ratio of having a high GOS with a low ASPECT score at discharge was OR 0.74 (95% CI 0.61–0.94, p = 0.003), and 3 months OR 0.73 (95% CI 0.59–0.91, p = 0.005). ASPECT score significantly correlates with clinical outcome in DCI post aSAH, even after correcting for Fisher grade. ASPECT scoring may identify patients at risk of poor outcome following DCI and represents a quick and reliable tool that aids in clinical decision-making and prognostication.

Diagnostic accuracy of shuttle CT angiography (CTA) and helical CTA in the diagnosis of vasospasm

PurposeTo evaluate the diagnostic accuracy of computed tomography angiography (CTA) acquired with shuttle technique (CTAs) and helical CTA (CTAh) for vasospasm, using digital subtraction angiography (DSA) obtained within 24 h as reference standard. MethodsThirty-six patients with suspected vasospasm in the setting of aneurysmal subarachnoid hemorrhage (ASAH, 30/36) or acute inflammatory/infectious conditions (6/36) who underwent CTAs (17/36) or CTAh (19/36) followed by DSA within 24 h were identified retrospectively. Presence of vasospasm in the proximal cerebral arterial segments was assessed qualitatively and semi-quantitatively on CTA and subsequent DSA. Sensitivity, specificity, and receiver operating characteristic (ROC) curves were calculated. Inter-rater variability was assessed using Cohen's kappa. ResultsOn CTAs, 35% of patients had low and 65% had high vasospasm burden. On CTAh, 37% had low and 63% had high vasospasm burden. ROC analysis demonstrated an AUC of 0.87 for CTAs (95%CI 0.67–1.00, p = 0.015) and 0.88 for CTAh (0.72–1.00, p = 0.028). Cohen's kappa was 0.843 (95%CI 0.548–1.000). Thresholding with Youden's J index, CTAs had a sensitivity of 85.71% (95%CI 48.69 to 99.27) and specificity of 66.67% (35.42 to 87.94). CTAh had sensitivity of 100% (56.55 to 100.00) and specificity of 78.57% (52.41 to 92.43). ConclusionCTAs and CTAh yielded similar sensitivity, specificity, and AUC values on ROC analysis for the detection of vasospasm using DSA as reference standard. Our findings suggest that CTAs is a promising alternative to CTAh especially in patients requiring serial imaging, given its potential advantages of decreased radiation exposure, contrast dose, and cost-effectiveness.

Arterial Spin Labeling for the Etiological Workup of Intracerebral Hemorrhage in Children.

Pediatric nontraumatic intracerebral hemorrhage accounts for half of stroke in children. Early diagnostic of the causative underlying lesion is the first step toward prevention of hemorrhagic recurrence. We aimed to investigate the performance of arterial spin labeling sequence (ASL) in the acute phase etiological workup for the detection of an arteriovenous shunt (AVS: including malformation and fistula), the most frequent cause of pediatric nontraumatic intracerebral hemorrhage. Children with a pediatric nontraumatic intracerebral hemorrhage between 2011 and 2019 enrolled in a prospective registry were retrospectively included if they had undergone ASL-magnetic resonance imaging before any etiological treatment. ASL sequences were reviewed using cerebral blood flow maps by 2 raters for the presence of an AVS. The diagnostic performance of ASL was compared with admission computed tomography angiography, other magnetic resonance imaging sequences including contrast-enhanced sequences and subsequent digital subtraction angiography. A total of 121 patients with pediatric nontraumatic intracerebral hemorrhage were included (median age, 9.9 [interquartile range, 5.8-13]; male sex 48.8%) of whom 76 (63%) had a final diagnosis of AVS. Using digital subtraction angiography as an intermediate reference, visual ASL inspection had a sensitivity and a specificity of, respectively, 95.9% (95% CI, 88.5%-99.1%) and 79.0% (95% CI, 54.4%-94.0%). ASL had a sensitivity, specificity, and accuracy of 90.2%, 97.2%, and 92.5%, respectively for the detection of the presence of an AVS, with near perfect interrater agreement (κ=0.963 [95% CI, 0.912-1.0]). The performance of ASL alone was higher than that of other magnetic resonance imaging sequences, individually or combined, and higher than that of computed tomography angiography. ASL has strong diagnostic performance for the detection of AVS in the initial workup of intracerebral hemorrhage in children. If our findings are confirmed in other settings, ASL may be a helpful diagnostic imaging modality for patients with pediatric nontraumatic intracerebral hemorrhage. URL: https://www.clinicaltrials.gov; Unique identifiers: 3618210420, 2217698.

Empiric cone-beam CT-guided embolization in acute lower gastrointestinal bleeding.

To evaluate the clinical effect and safety of cone-beam CT (CBCT)-guided empirical embolization for acute lower gastrointestinal bleeding (LGIB) in patients with a positive CT angiography (CTA) but subsequent negative digital subtraction angiography (DSA). A retrospective study of consecutive LGIB patients with a positive CTA who received a DSA within 24h from January 2008 to July 2019. Patients with a positive DSA were treated with targeted embolization (TE group). Patients with a negative DSA underwent an empiric CBCT-guided embolization of the assumed ruptured vas rectum (EE group) or no embolization (NE group). Recurrent bleeding, major ischemic complications, and in-hospital mortality were compared by means of Fisher's exact test. Further subgroup analysis was performed on hemodynamic instability. Eighty-five patients (67.6years ± 15.7, 52 men) were included (TE group, n = 47; EE group, n = 19; NE group, n= 19). If DSA was positive, technical success of targeted embolization was 100% (47/47). If DSA was negative and the intention to treat by empiric CBCT-guided embolization, technical success was 100% (19/19). Recurrent bleeding rates in the TE group, EE group, and NE group were 17.0% (8/47), 21.1% (4/19), and 52.6% (10/19) respectively. Empiric CBCT-guided embolization reduced rebleeding significantly in patients with a negative DSA and hemodynamic instability (EE group, 3/10 vs NE group, 10/12, p = .027). Major ischemic complications occurred in one patient (TE group). Overall, the in-hospital mortality rate was 7.1% (6/85). Empiric cone-beam CT-guided embolization proved to be a feasible, effective, and safe treatment strategy to reduce rebleeding and improve clinical success in hemodynamically unstable patients with acute LGIB, positive CTA but negative DSA. • A novel transarterial embolization technique guided by cone-beam CT could be developed extending the "empiric" embolization strategy to lower gastrointestinal bleeding. • By implementing the empiric treatment strategy, nearly all patients with an active lower gastrointestinal bleeding on CTA will be eligible for a superselective empiric embolization, even if subsequent catheter angiography is negative. • In patients with a negative catheter angiography, empiric embolization reduces the rebleeding rate and, particularly in hemodynamically unstable patients, improves clinical success compared with a conservative "wait-and-see" management.

Magnetic resonance imaging as a single diagnostic tool for verifying radiosurgery outcomes of cavernous sinus dural arteriovenous fistula

PurposeMRI and MR angiography (MRA) are noninvasive methods for examining cavernous sinus dural arteriovenous fistulas (CSDAVFs) after radiosurgery. In this study, we investigated the accuracy of unenhanced MRI/3-dimensional time-of-flight (3D TOF) MRA in evaluating CSDAVF obliteration as compared with digital subtraction angiography (DSA). MethodsFrom 1995–2012, 48 cases of CSDAVFs received Gamma Knife surgery (GKS) and had undergone both unenhanced MRI/3D TOF MRA and DSA for posttreatment evaluation. Two blinded observers independently interpreted the results of MRI/MRA. The results of MRI/MRA were compared with those of DSA. The sensitivity (the probability of MRI/MRA showing obliteration when DSA showed complete obliteration), specificity, positive predictive value, and negative predictive value for CSDAVF obliteration were reported. ResultsThe median interval between the final MRI/MRA and the subsequent DSA was 2 months. Follow-up DSA revealed that 38 of 48 (79.2 %) CSDAVFs were completely obliterated. The results of interobserver agreement assessment showed almost perfect agreement between the 2 observers. For unenhanced MRI/3D TOF MRA, the observed sensitivity was 84.2 %, specificity was 100 %, positive predictive value was 100 %, and negative predictive value was 62.5 %. ConclusionsUnenhanced MRI/3D TOF MRA alone may be adequate to document the complete obliteration of CSDAVFs after GKS. Time-resolved MRA or DSA can be reserved for a suspected residual CSDAVF after a sufficient latency period after GKS.

Role of digital subtraction angiography in detection of intracranial aneurysms compared with computed tomographic angiography

Objective To evaluate the role of digital subtraction angiography (DSA) in the detection of intracranial aneurysms among patients with spontaneous subarachnoid hemorrhage (SAH) compared with computed tomographic angiography (CTA) in a single center, Sri Lanka. Methods A total of 123 patients clinically and CT proven SAH were evaluated with CT angiography and DSA with a median interval of 3 days. The sensitivity, specificity and accuracy of CT angiography in detecting aneurysms were analyzed compared to DSA on a per-patient, per-size, per-site and per morphological basis. All data were analyzed using SPSS analytical package (version 18). Ethical approval for the study was from the institutional ethical review board. Results Among 123 patients with clinically and CT proven SAH, 51 (41.5%) patients showed aneurysms on CT angiography. 72 were negative for aneurysms in CTA. In 13 out of 72 (18%) CTA negative patients subsequent DSA demonstrated aneurysms. Number of CTA negative but DSA positive aneurysm were 15 as two of the patients had two aneurysms each. Four CTA detected aneurysms could not be appreciated in the subsequent DSAs. Aneurysms (47)detected by both CT angiography and DSA were more than 6mm in size (56.7%) , sacculartype (96.5%) and were located in the anterior circulation system (92.4%). Most CTA negative aneurysms detected by DSA were less than 6mm in size (80%), saccular type (60%) and were located in anterior (53.8%) and posterior (46.7%) circulation system. The sensitivity, specificity, positive predictive value and negative predictive value of CT angiography compared to DSA per patient basis were 78.3%, 93.7%, 92.2% and 81.9% respectively. CT angiography has a low sensitivity to detect aneurysms less than 6mm size (65.7%%), in posterior circulation (36.4%) and other morphological types (0%) compared to aneurysms more than 6mm size (90.9%), in anterior circulation (85.9%) and saccular type (85.5%). Conclusion Digital subtraction angiography (DSA) has a significant role in detecting intracranial aneurysms which are less than 6mm in size, are located in posterior circulation system and of non-saccular morphological type.

Digital subtraction cerebral angiography after negative computed tomography angiography findings in non-traumatic subarachnoid hemorrhage

BackgroundCT angiography (CTA) is widely used for the detection of vascular lesions in patients with non-traumatic subarachnoid hemorrhage (ntSAH); however, digital subtraction angiography (DSA) remains the gold standard for diagnosis....

Congenital arteriovenous fistula between descending aorta and the left innominate vein

Thoracic aortocaval fistulae are rare entities where a direct shunt between thoracic arteries and systemic veins is seen. They can be traumatic or congenital in origin. Congenital thoracic aortocaval fistulae usually involve descending aorta and azygos, hemiazygos systems. Presenting symptoms range from continuous murmur to signs of congestive heart failure. In this case report, imaging findings of a 3-year-old girl referred for continuous murmur over the left sternal border are presented. Computed tomography angiography revealed multiple tortuous vessels along the descending aorta with a course toward the left brachiocephalic vein, and was suspicious for an aorta-venous fistula. Subsequent digital subtraction angiography for treatment planning showed a fistula originating at the level of the left 6th intercostal artery, with direct drainage into the left brachiocephalic vein without involvement of the azygos/hemiazygos system.

Meatal Anterior Inferior Cerebellar Artery Aneurysm with AICA-PICA Complex: Endovascular Coiling and Parent Artery Preservation

AbstractSecondary stroke prevention requires early initiation of antiplatelet; therefore, stroke mimics need to be ruled out particularly in circumstances when antiplatelet therapy can be of disastrous consequences. A 54-year-old female patient presented to the emergency department with symptoms of sudden-onset deviation of angle of mouth to the right side, left eye ptosis, and occipital headache for past 4-hour duration. Neurologic examination revealed right-sided gaze-dependent torsional nystagmus and left lower motor neuron facial weakness. An embolic posterior circulation stroke secondary to vertebral artery dissection was suspected. Diffusion-weighted imaging (DWI) did not show any acute infarcts, and careful review of susceptibility-weighted imaging (SWI) scans showed hemorrhage in the fourth ventricle. Subsequent digital subtraction angiography (DSA) was done, which showed left anterior inferior cerebellar artery (AICA) aneurysm involving its intrameatal segment with AICA-posterior inferior cerebellar artery (PICA) complex. Retrospective review of computed tomographic (CT) angiography images showed small aneurysm in the internal auditory meatus, which is difficult to discern secondary to adjacent bony structure and smaller size of the aneurysm. The patient underwent endovascular coiling of the aneurysm with preservation of the parent artery. Our experience concluded that these clinical features suggest remote subarachnoid hemorrhage secondary to the ruptured of AICA intrameatal segment aneurysm with left facial nerve paralysis and peripheral cochlear vestibular changes secondary to either compression (mechanical or pulsations of the aneurysm sac) or ischemia of vestibular apparatus. The neurointerventionist should consider the possibility of aneurysmal rupture, especially in cases of atypical location of hemorrhage and no signs of infarct on neuroimaging of posterior circulation stroke.

Modified calcium subtraction in dual-energy CT angiography of the lower extremity runoff: impact on diagnostic accuracy for stenosis detection.

To investigate the diagnostic accuracy of a modified three-material decomposition calcium subtraction (CS) algorithm for the detection of arterial stenosis in dual-energy CT angiography (DE-CTA) of the lower extremity runoff compared to standard image reconstruction, using digital subtraction angiography (DSA) as the reference standard. Eighty-eight patients (53 males; mean age, 65.9 ± 11years) with suspected peripheral arterial disease (PAD) who had undergone a DE-CTA examination of the lower extremity runoff between May 2014 and May 2015 were included in this IRB-approved, HIPAA-compliant retrospective study. Standard linearly blended and CS images were reconstructed and vascular contrast-to-noise ratios (CNR) were calculated. Two independent observers assessed subjective image quality using a 5-point Likert scale. Diagnostic accuracy for ≥ 50% stenosis detection was analyzed in a subgroup of 45 patients who had undergone additional DSA. Diagnostic accuracy parameters were estimated with a random-effects logistic regression analysis and compared using generalized estimating equations. CS datasets showed higher CNR (15.3 ± 7.3) compared to standard reconstructions (13.5 ± 6.5, p < 0.001). Both reconstructions showed comparable qualitative image quality scores (CS, 4.64; standard, 4.57; p = 0.220). Diagnostic accuracy (sensitivity, specificity, positive and negative predictive values) for CS reconstructions was 96.5% (97.5%, 95.6%, 90.9%, 98.1) and 93.1% (98.8%, 90.4%, 82.3%, 99.1%) for standard images. A modified three-material decomposition CS algorithm provides increased vascular CNR, equivalent qualitative image quality, and greater diagnostic accuracy for the detection of significant arterial stenosis of the lower extremity runoff on DE-CTA compared with standard image reconstruction. • Calcified plaques may lead to overestimation of stenosis severity and false positive results, requiring additional invasive digital subtraction angiography (DSA). • A modified three-material decomposition algorithm for calcium subtraction provides greater diagnostic accuracy for the detection of significant arterial stenosis of the lower extremity runoff compared with standard image reconstruction. • The application of this algorithm in patients with heavily calcified vessels may be helpful to potentially reduce inconclusive CT angiography examinations and the need for subsequent invasive DSA.

Abstract TP149: The Effects of Intravenous Thrombolysis on Distal Migration of Clots and Recanalization in Acute Ischemic Strokes Also Treated With Endovascular Therapies

Introduction: The role of intravenous recombinant tissue plasminogen activator (IV r-tPA) prior to endovascular therapy (ET) in acute ischemic stroke (AIS) has been heavily debated in recent literature. Understanding the direct relationship of IV r-tPA to occlusive thrombus size and migration may lead to further understanding of the potential benefits of IV r-tPA in AIS cases treated with ET. Methods: We retrospectively studied consecutive AIS patients who underwent a CT angiogram (CTA) followed by ET at our center from 7/2016-1/2017. We compared demographic, clinical, and imaging characteristics between subjects treated with or without IV r-tPA. Three raters, blind to IV r-tPA exposure, independently evaluated clot burden and location of each thrombus on CTA in comparison to digital subtraction angiography (DSA) images. Results: Among 29 patients meeting inclusion/exclusion criteria, 16 received IV r-tPA prior to ET and 13 received ET alone. Agreement among raters ranged from 0.296 (clot burden score of thrombus on DSA) to 0.800 (location of thrombus on CTA). There were no statistically significant differences in the treated and untreated groups (Table). The odds of distal migration of clot or recanalization on subsequent DSA among tPA treated patients was more than 4 times that of non-tPA treated patients (OR 4.28, 95% CI 0.71, 25.92). Conclusion: In summary, 43.8% of patients in the IV r-tPA plus ET treated group exhibited distal migration of a thrombus or recanalization when observed on DSA, compared to 15.4% in the ET-only group. Although our results suggest that IV r-tPA may change the size and location of the thrombus, our results were not adequately powered to detect significant differences. However, the inter-rater reliability was favorable, suggesting that this investigational technique may be successfully applied to a larger sample size in future studies investigating the role of IV r-tPA bridging therapy in AIS treated with ET.

Significance of pelvic contrast enhanced MRA prior to prostatic artery embolization

Objective: To assess the values of pelvic contrast enhanced magnetic resonance angiography (MRA) in detection of prostatic artery prior to prostatic arterial embolization(PAE). Methods: This multicenter, prospective study from 5 hospitals in China consisted of 47 patients (mean age (69±16) years, range 56-83 years) who underwent PAE for benign prostatic hyperplasia (BPH) between January 2016 and April 2018, preprocedural prediction of prostatic arteries were determined using contrast enhanced MRA.CE-MRA findings were compared with subsequent intraprocedural digital subtraction angiography (DSA) or DSA combined with cone-beam computed tomography (CT) to assess the sensitivity and specificity with which contrast enhanced MRA predicted the number and origins of prostatic artery, also to assess the optimal oblique projection of PA. Results: In total, 47 patients (94 pelvic sides) with 97 PAs confirmed by DSA or DSA combined with cone-beam CT at the time of embolization, MR angiography successfully identified 88 PAs and their origins , the sensitivity and specificity was 90.7% (88/97) and 93.6% (88/94), respectively.MR angiography correctly determined the bilateral prostatic artery origins in 36 (76.6%) cases.According to the optimal oblique projection of PAs suggested by MR angiography, the origins and trajectory of PAs of all patients underwent PAE with the same oblique projection (20°-45°ipsilateral anterior oblique direction) were clearly displayed when performed the first arteriography. Conclusion: Pelvic contrast enhanced MR angiography with high sensitivity and specificity in detection the origin, trajectory and number of PAs, and it could provide useful information regarding prostatic arteries before PAE.