Initial Computed Tomography Angiography Research Articles

1. To develop a deep-learning segmentation model for automated measurement of maximal aortic diameter (Dmax) and volumes of aortic dissection components: true-lumen (TL), circulating false-lumen (CFL), and thrombus (Th) on CT angiography (CTA). 2. To assess the predictive value of these measures for adverse aortic remodeling in residual aortic dissection (RAD). This retrospective study included 322 patients from two centers. The segmentation model was trained on 120 patients (Center 1) and tested on an internal dataset (30 patients, Center 1) and an external dataset (10 patients, Center 2) in terms of Dice Similarity Coefficient (DSC). The model extracted Dmax, global false-lumen volume (FLGlo = CFL + Th), and local false-lumen volume (FLLoc, measured 3 cm around the largest diameter). Clinical validation was performed on 83 patients from Center1 (internal validation, 2-year follow-up) and 79 patients from Center2 (external validation, 4.5-year follow-up). The segmentation model achieved high accuracy (Center 1, DSC: 0.93 TL, 0.93 CFL, 0.87 Th; Center 2, DSC: 0.92 TL, 0.93 CFL, 0.84 Th) with strong agreement between automated and manual measurements. Aortic remodeling occurred in 39/83 patients (46.9%) from Center1 and 33/79 patients (41.7%) from Center2. Aortic remodeling occurred in 39/83 patients (47%) from Center1 and 33/80 (42%) from Center2. FLLoc outperformed Dmax and FLGlo (Center 1: AUC = 0.83, 0.73, and 0.76; Center 2: AUC = 0.77, 0.64, and 0.70). At optimal thresholds, FLLoc showed good predictive performance (Center 1: Sensitivity = 0.87, Specificity = 0.68). Deep-learning segmentation provides accurate aortic measurements. Local false-lumen volumes predict adverse aortic remodeling in RAD better than diameter and global false-lumen volumes. Question In residual aortic dissection (RAD) after type-A dissection, early identification of high-risk patients on initial CT angiography is crucial for endovascular treatment decisions. Findings False-lumen local volumes (3 cm around aortic dissection maximal diameters), obtained with an automatic deep-learning method, predict adverse remodeling better than diameter or global false-lumen volumes. Clinical relevance A deep-learning segmentation method of aortic dissection components on CTA, enabling automatic measurements of diameters and volumes is feasible. It provides local false-lumen volumes, a better predictive marker of adverse aortic remodeling than the currently used diameters and global volumes.

Description of Case: A 78-year-old man with a history of Parkinson’s, TIAs, and scoliosis presented with a sequalae of symptoms concerning for recurrent TIA, however extensive workup demonstrated no evidence of acute intracranial abnormalities. Subsequently, he developed acute hypoxic respiratory failure requiring high-flow nasal cannula. Initial chest CT angiography (CTA) and X-ray were negative for acute pulmonary pathology. A transthoracic echocardiogram (TTE) with bubble study was positive for moderate right-to-left shunt through a patent foramen ovale (PFO). Subsequent imaging modalities, including right heart catheterization, transesophageal echocardiography (TEE) with bubble study, cardiac CT, and cardiac MRI, exhibited normal hemodynamics, positive PFO with left-to-right shunt, and no evidence of significant right-to-left shunt (normal Qp:Qs). Of note, he was discovered to have significant hypoxia while sitting up but remained on room air while supine. In order to evaluate for platypnea-orthodeoxia syndrome (POS), TTE with agitated saline contrast was performed which was grossly positive after 5 cardiac cycles while in the supine position and 3 cardiac cycles while upright, raising concern for pulmonary arteriovenous malformations (AVMs). However, repeat CTA was negative for pulmonary AVMs. Finally, repeat TEE bubble study was performed while the patient was supine (Images A) and sitting up (Images B) which demonstrated a PFO with bidirectional shunting. While the patient was sitting up (Images B), there was stretching of the PFO with significant, continuous right-to-left shunting likely precipitated by the patient’s significant scoliosis. The patient underwent successful percutaneous PFO closure (Images C), which immediately resolved his hypoxia. Discussion: POS is a rare but important clinical phenomenon characterized by positional dyspnea and hypoxemia that worsen in the upright position and improve when supine. This syndrome is mostly associated with intracardiac shunts, such as a PFO, but may also be exacerbated by extrinsic anatomical factors. This rare case report of POS demonstrated a PFO that was exacerbated by vertebral deformity and mediastinal distortion (severe scoliosis) facilitating significant right-to-left shunting in the upright position. The case highlights the critical role of spinal anatomy in the pathophysiology of POS, especially with existing PFO, and the importance of multimodality imaging in diagnosing positional hypoxemia.

Background Reversible cerebral vasoconstriction syndrome (RCVS) is a rare but severe neurovascular complication following cardiac transplantation. Its diagnosis is often complicated by atypical presentations and by neuroimaging limitations, as transplant-related devices can hinder timely magnetic resonance (MR) imaging. Case presentation A 59-year-old woman developed a severe headache 9 days post-cardiac transplantation. Neurological examination revealed left lower quadrantanopia. A head Computed Tomography (CT) scan showed a subdural hematoma, along with a subcortical and convexity subarachnoid hemorrhage in the right parieto-occipital lobe. Initial CT angiography showed only focal arterial stenosis. On day 10, she developed left hemineglect. After removal of transplant-related devices, MR imaging showed a watershed infarct and MR angiography revealed multiple vasospasms. Diagnostic challenges The diagnostic challenge was the delayed onset of diffuse vasospasms, the confirmation of which was precluded by the initial contraindication to MR imaging. Management The patient was diagnosed with RCVS. Management included withdrawal of tacrolimus and initiation of oral verapamil and prasugrel. This led to rapid clinical and radiological improvement. Conclusion This case highlights that RCVS can present with a subdural hematoma before the onset of delayed vasospasm after cardiac transplantation. Repeated cerebrovascular evaluations are crucial for timely diagnosis and management in post-transplant patients with unexplained headaches or intracranial hemorrhage.

BackgroundIdentifying the aetiology of ischemic stroke can be challenging, especially when critical findings are overlooked. Stroke assessment often relies on standardised guidelines, primarily focused on carotid stenosis severity (>50%) as an intervention criterion. However, this approach may neglect high-risk plaque features. This case report highlights the importance of integrating diagnostic findings with clinical presentation to guide management.Case presentationA 68-year-old male presented with sudden-onset transient right arm weakness. Initial imaging, including MRI and CT angiography, revealed a subtle diffusion-weighted imaging (DWI) abnormality in the left hemisphere and moderate carotid atherosclerosis (<50%) that did not meet guideline criteria for endarterectomy. Despite antiplatelet and anticoagulant therapy, the patient experienced multiple recurrent ischemic episodes. Due to the persistence of symptoms, the multidisciplinary team (MDT) recommended advanced vessel wall MRI, which identified intraplaque haemorrhage and plaque ulcerations in the left internal carotid artery-critical findings missed on conventional imaging. This led to a decision to perform carotid endarterectomy. Histology confirmed atheromatous disease with intraplaque haemorrhage. Following surgery, the follow-up scans showed no new infarcts with no clinical recurrence.DiscussionThis case underscores the limitations of relying solely on carotid stenosis degree in stroke management and highlights the importance of identifying high-risk plaque characteristics. Advanced vessel wall imaging proved instrumental in guiding treatment, while MDT collaboration ensured a tailored approach. The findings emphasise the need to prioritise carotid stenosis characteristics over stenosis degree alone when guiding clinical decisions to optimise outcomes in ischemic stroke management.

To assess the diagnostic yield and clinical relevance of repeated digital subtraction angiography (DSA) in patients with spontaneous perimesencephalic non-aneurysmal subarachnoid hemorrhage (PMSAH) and to evaluate DSA-related complication rates. Retrospective analysis of 82 patients with PMSAH confirmed by non-contrast CT between March 2002 and February 2025. All patients underwent initial computed tomography angiography (CTA) and first DSA on average within 24h. If no bleeding source was identified, a second DSA was performed after 10-14 days. Clinical data, radiological findings, and complications were evaluated. The initial DSA showed no vascular abnormality in 76/82 patients (92.7%). A second DSA was performed in 60/76 cases (78.9%) and identified two small basilar artery aneurysms (3.3%) that were not visible on the initial CTA or DSA but were detectable on repeat 3D rotational angiography (3DRA). Procedure-related complications occurred in three DSAs (2%), including a cerebellar infarct, supratentorial embolism, and local puncture site complication. Most patients had a benign clinical course, and only one in-hospital death was documented. The diagnostic benefit of repeat DSA in typical PMSAH is low, with no clear therapeutic impact and a relevant risk of complications. Given the benign course of PMSAH and the availability of high-resolution non-invasive imaging such as dual-source, photon-counting CTA, or vessel wall MRI, repeat DSA should be reserved for selected cases with atypical features or clinical deterioration.

The literature shows that anterior communicating artery (AcoA) aneurysms are the most common intracranial aneurysms. To date, there has only been one postmortem study focused on the correlations between autopsy findings and imaging results in cases of intracranial aneurysms associated with anatomical variants of the circle of Willis (CW). We investigated the anatomical variants of the CW associated with the occurrence and rupture of AcoA aneurysms by performing comparative analyses, in the same patients, of postmortem autopsy data with antemortem computed tomography-angiography (CTA) results obtained in the first 48 h after the onset of subarachnoid hemorrhage. Our retrospective observational study identified the anatomical variants of the CW at autopsy in 16 deceased adult Romanian patients with AcoA aneurysms over a 12-year period (2010-2022). The autopsy findings revealed that the AcoA ruptured aneurysms had a mean external diameter of 9.50 mm, and 71.4% of them presented three or four anatomical variants inside the same CW. The initial antemortem CTA examination correctly located the AcoA aneurysms in all cases (100%), and an anatomical variant of the CW was only noted in 18.75% of patients. The final postmortem re-analyzed the same CTA images identified in all cases (100%), focusing on both the AcoA aneurysm and all anatomical variants of the CW found during the autopsies. Although it was previously thought that the occurrence of AcoA aneurysms is related only to the hemodynamic changes induced by the nearby arterial anatomical variants, we identified the simultaneous involvement of at least one hypoplastic artery and one or two PCA fetal-type anatomical variants that were located in both the anterior and posterior parts of the CW. Furthermore, if sufficient time is devoted to the CT-angiography analysis and interpretation of the images, anatomical variants of the circle of Willis associated with AcoA aneurysms can be identified as accurately as they are in invasive postmortem autopsy examinations.

Background: Pseudoaneurysms of the subclavian artery are uncommon and typically result from penetrating or blunt trauma. Early diagnosis and prompt management are essential to prevent life-threatening complications. Case Presentation: We present the case of a 30- year- old male involved in a motor vehicle accident, resulting in multiple severe injuries, including a rare traumatic pseudoaneurysm of the proximal right subclavian artery. Initial computed tomography angiography (CTA) revealed a 12 12 mm pseudoaneurysm which increased to 17 12 mm within 48 hours despite supportive care. Due to rapid deterioration and progression of intracranial hemorrhage, surgical repair could not be performed, and the patient succumbed on the fourth day of admission Conclusion: Subclavian artery pseudoaneurysms should be suspected in high energy chest trauma, especially when cervical vertebral injuries coexist. CTA remains the diagnostic modality of choice. Endovascular management is increasingly favored for its minimally invasive nature and favorable outcomes.

ObjectiveFalse lumen expansion is a major factor that determines long-term survival of uncomplicated type B aortic dissection (TBAD). The objective of this study was to investigate whether structural wall stress distributions computed from patient-specific acute TBAD geometries can be used to predict aortic growth rates.MethodsThree-dimensional (3D) computed tomography angiography (CTA) of 9 patients with acute uncomplicated TBAD were obtained at initial hospital admission and at their most recent follow-up visits. Patient-specific structural wall stress distributions were computed from the initial baseline CTA using a forward penalty method. Spatially varying blood pressure distributions, derived from computational fluid dynamics (CFD) simulations informed by patient-specific transthoracic echocardiography (TTE) and blood pressure (BP) measurements, were incorporated into the forward penalty stress analysis. Aortic growth rates were quantified and visualized within the 3D TBAD geometries using the initial baseline and follow-up scans. Linear mixed-effects regression analyses were performed to evaluate the spatial correlations between biomechanical markers (structural wall stress, wall shear stress, and pressure) and aortic growth rates.ResultsUtilizing initial baseline CTA, TTE, and BP data, the forward penalty analyses revealed hemodynamic and structural mechanics insights of acute uncomplicated TBADs. The linear mixed-effects model indicated that the fixed-effect association between structural wall stress and aortic growth rate distributions was statistically significant (p=0.039), which demonstrated that aortic segments experiencing high wall stress exhibited rapid growth. Fixed-effect associations were not significant when predicting growth rate using wall shear stress (p=0.86) or pressure (p=0.61) distributions. Significant Pearson correlation coefficients (p<0.05) were observed between structural wall stress and aortic growth rate in all patients.ConclusionHigh structural wall stress was associated with regions of high aortic growth rates, while false lumen thrombosis was associated with low wall stress. Structural wall stress derived from the forward penalty approach may be a novel predictor of aortic growth rate and failure of optimal medical therapy in acute TBAD.

Background and Aims: Previous studies indicated the usual dose heparin(5000 IU bolus followed by 500~1250 IU/h) during mechanical thrombectomy(MT) is associated with an increased risk of hemorrhagic conversion without beneficial effect. East Asians are known to have a higher risk of bleeding compared to other races, and they often take lower doses of antithrombotics. However, role of minimal-dose heparin as an adjuvant treatment during MT in East Asians remains unclear. Methods: We enrolled the patients who underwent MT from the Inha University Hospital Stroke Prospective Registry and compared clinical findings between patients who received heparin during MT and those who did not. Results: From January 2016 to March 2024, 460 patients (68.8 years, 270 men) were included, and 70(15.2%) subjects received intravenous heparin, dose 500-1000 IU bolus, followed by 500 IU per hour. There were no differences in baseline characteristics or procedural parameter including procedural time, device, and TICI grade between two groups. However, intravenous thrombolysis was performed more frequently in the non-user group than in the heparin group, and the apTT value after the procedure was higher in the heparin group than in the other groups(75.9±12.5 vs 40.8±10.1 sec). The risk of hemorrhagic conversion on image was significantly higher in heparin group than non user group(31.4% vs 21.3%, p=0.04). This trend also seemed to be seen in patients who did not undergo intravenous thrombolysis group. This Early distal migration of embolus, defined as difference location of embolus between initial CT angiography and initial conventional angiographym was observed more frequently in heparin group, compared with non-user group. However, there was no difference in mRS at 90 days and early neurological deficit between the two groups. Conclusions: Even minimal dose of intravenous heparin injection around MT was associated with an increased risk of hemorrhagic conversion and distal migration without significant change in functional outcome or recanalization status.

For patients with suspected traumatic vertebral artery injury (TVAI), CT angiography (CTA) is the first-line screening modality. Digital subtraction angiography (DSA) serves as the confirmatory diagnostic imaging, and is the gold standard for cerebrovascular injury assessment, due to its higher sensitivity and specificity. Among patients with TVAI based on CTA who have undergone follow-up DSA, this study aims to investigate how diagnostic information with additional imaging affects clinical management. A retrospective review was conducted over 7 years (2016-2023) at a level 1 trauma center for TVAI patients undergoing both CTA and DSA. Pre- and post-DSA approaches to TVAI management were compared and summarized using propensity-score matched analysis. Among the 69 patients studied, 24.6% were determined to have false-positive TVAI after DSA. The rate of change in management after DSA was significantly different across DSA+ and DSA- cohorts (p = 0.02). The likelihood of a change in management in patients with based on outcome of the DSA was significant (p = 0.03) in the propensity-matched cohort. On average, 3 (NNI = 3.2) patients would need to receive a DSA for one additional patient to undergo a change in management. This study demonstrates that, despite initial CTA imaging suggestive of TVAI, follow-up DSA imaging negative for TVAI has a significant impact on changing clinical management, including cessation of antithrombotic agents. Thus, for TVAI patients, DSA may be considered in the diagnostic workup for select patients with positive CTA. Larger cohort analyses are needed to refine imaging algorithms and optimize clinical outcomes for TVAI patients.

Urethrocavernous fistula: a case report and systematic review.

Background: Abdominal Aortic Aneurysm (AAA) is defined as a permanent dilation of the artery with a lumen diameter at least 50% larger than the proximal normal segment. Risk factors for AAA include advanced age, male gender, smoking history, hypertension, and a family history of AAA. AAA remains a leading cause of mortality in the United States due to aneurysm rupture. This study aims to highlight the role of radiological imaging in the management of AAA cases. Case Presentation: A 70-year-old man initially presented with a lump near the umbilical region. One year later, he returned to the hospital complaining of severe abdominal pain in the same area. The initial thoracoabdominal CT angiography revealed an AAA with signs of impending rupture. A subsequent CT scan performed one year later confirmed a ruptured aneurysm. Conclusion: Radiological imaging, particularly CT angiography, is critical in the diagnosis and pre-operative assessment of AAA. Key imaging findings include aneurysm size, length, morphology, location, presence of atherosclerosis, intraluminal thrombus, and features indicating aneurysm instability. These parameters are essential for guiding clinical decision-making and optimizing patient outcomes.

Abstract Disclosure: S. Hassan: None. Background: Pheochromocytomas can lead to vasoconstriction and its various clinical manifestations due to excess catecholamine release. Critical limb ischemia as a clinical manifestation of pheochromocytoma has been reported sparsely. Clinical Case: A 43 year old female with a past medical history of type 2 diabetes mellitus, Turner syndrome, and hypertension presented to the emergency department with acute on chronic left leg pain. She underwent workup with a CT angiography of the abdomen with runoff for evaluation of her vessels, which revealed an occlusion of her left superficial femoral artery with chronic stenosis of the right femoral system. Multiple unsuccessful attempts were made at revascularization of her left lower extremity, including femoropopliteal bypass, with eventual left above knee amputation, multiple fasciotomies, and angiogram and stenting of multiple vessels. The patient was on a combined OCP (norethindrone-ethinyl estradiol) for hormone replacement for Turner syndrome for the past 30 years, and did not have a personal or family history of clotting disorders. She underwent a hypercoagulable workup which was negative. Echocardiogram was negative for thrombi and was otherwise unremarkable. Incidentally discovered on her initial CT angiography was a heterogeneously enhancing right adrenal mass, which was further delineated on a dedicated CT of the adrenals, which showed a 3.7 cm right adrenal mass with pre-contrast Hounsfield units measuring 46. Biochemical workup revealed a normal plasma renin activity and aldosterone, plasma metanephrine elevated to 5.20 nmol/L (range 0.00 – 0.49 nmol/L), plasma normetanephrine elevated to 4.95 nmol/L (range 0.00 – 0.89 nmol/L), 24 hour urine metanephrine elevated to 3830 ug/d (range 36-229 ug/d), and 24 hour urine normetanephrine 1733 ug/d (range 95 – 650 ug/d). She reports a diagnosis of hypertension at age 36, with no secondary workup pursued; she had suboptimal control on three separate medications, lisinopril, metoprolol, and hydrochlorothiazide. Her blood pressure and heart rate were noted to be labile during her aforementioned surgery. Alpha blockade with doxazosin was started based on her significantly elevated plasma and urine metanephrines and normetanephrines, with improvement in her blood pressure control. She was not found to have a definitive cause of her critical limb ischemia; she was noted to have atherosclerosis in the vessels of her lower extremities, and her chronic oral contraceptive use may also have played a role. However, OCPs are often reported to cause venous rather than arterial thrombi. Therefore, it can be inferred that the catecholamine excess from her presumed pheochromocytoma caused vasoconstriction which may have played a role in the development of her critical limb ischemia. Conclusion: Catecholamine excess that is resultant from a pheochromocytoma may manifest as critical limb ischemia. Presentation: 6/1/2024

INTRODUCTION: Acute gastrointestinal bleeding is a common gastrointestinal emergency. Only limited studies are available regarding the clinical outcomes after computed tomographic angiography (CTA) mesentery showed negative for active bleed. This study aims to determine the clinical outcome of negative mesentery CTA in patients with clinically active acute gastrointestinal (GI) bleeding. MATERIAL AND METHODS: A cross-sectional study with a universal sampling method was used. Patients who underwent CTA to detect gastrointestinal bleeding in the National University Hospital of Malaysia from December 2015 until March 2021 were retrospectively analysed. The outcome of each patient, risk of re-bleeding, and 30-days mortality rate were evaluated and assessed. RESULTS: In total, 280 CTAs were performed on 232 patients, with 186 of them showing negative results on their first initial CTA. 40.8% (76/186) of those with negative initial CTA had recurrent bleeding and 73.6% (56/76) of them required active intervention. We found that the risk of re-bleeding is lower in the upper gastrointestinal group compared to the lower gastrointestinal group (OR=1.5, 95% CI: 0.877- 2.852, p: 0.128). The overall 30 days mortality rate after the first negative CTA was 23.1% (43/186). Among those patients who experienced re-bleeding, 32.8% (25/76) died within 30 days, with 18.4% (14/76) succumbing to massive bleeding. CONCLUSION: From our analysis, it can be concluded that a clinically active GI bleeding with negative mesentery CTA has a 40.8% chance to re-bleed with 23.1% 30-day mortality rate. Close observation and follow-up

Ruptured aneurysms of the lateral spinal artery (LSA) causing subarachnoid hemorrhage (SAH) are exceptionally rare. Unlike common aneurysms in the circle of Willis, LSA aneurysms present unique diagnostic and therapeutic challenges due to their complex anatomy. We reviewed the literature, examining case reports detailing LSA aneurysm occurrences, diagnoses, treatments, and complications, and our subsequent analysis highlights the clinical presentations, imaging findings, treatment methods, and anatomical features of the LSA. We identified 10 patients from 7 case reports of LSA aneurysm presenting with SAH, and combined with the present case, this comprised a total of 11 patients. An initial CT angiography identified LSA aneurysm in only 2 of 11 patients, while 5 cases were detected in transfemoral cerebral angiography. Seven patients had stenosis or occlusion of nearby arteries. Among the 10 patients treated, 7 underwent microsurgical clipping, and 3 had endovascular treatment; complications included PICA infarction and subdural hematoma. LSA aneurysms, though rare, should be considered in differential diagnoses of posterior fossa SAH. An accurate diagnosis often requires repeated imaging. It is proposed to individualize treatment strategies based on the unique anatomical structure and hemodynamic conditions of each patient, utilizing both endovascular and surgical approaches. Understanding the vascular anatomy and collateral pathways of the LSA is crucial for improving diagnostic accuracy and treatment outcomes.

Acute ischemic stroke in young adults typically carries significant implications for morbidity, mortality, and long-term disability. In this study, we describe the case of a 34-year-old male with no prior medical history who presented with symptoms of right-sided weakness and slurred speech, suggesting an acute ischemic stroke. Initial CT angiography revealed an occlusion in the left M2 segment middle cerebral artery (MCA). The occlusion was successfully recanalized through emergent endovascular thrombectomy, which also identified a dissection as the cause of the stroke. Follow-up assessments at 3 days and three months, which included advanced vessel wall MRI, highlighted the critical role of intracranial artery dissection in strokes among young adults and provided essential images for ongoing evaluation.

Spontaneous renal haemorrhage is a rare occurrence with potentially serious consequences. This presented case was an even rarer form of ureteropelvic obstruction (UPJO), which was spontaneous bleeding into the renal pelvis in a patient who was not previously investigated for UPJO. We presented a 17-year-old gentleman who presented with lower abdominal pain for one week and painless haematuria for two days. Initial computed tomography angiography (CTA) renal revealed haematoma with a grossly dilated pelvicalyceal system. The patient was initially treated conservatively. However, in the ward, he suddenly developed severe left-sided back pain, decreased haemoglobin level and persistent gross haematuria. Repeated CTA renal revealed worsening left renal haematoma with a grossly dilated pelvicalyceal system, and he was panned for nephrectomy. A review of the literature followed with a discussion of the case were done in this study.

The role of number of affected vessels on radiologic and clinical outcomes of patients with blunt cerebrovascular injury

PurposeIt is currently unclear how useful repeat computed tomography angiography (CTA) is in spontaneous subarachnoid haemorrhage (SAH) patients after negative initial digital subtraction angiography (DSA). The purpose of this study is to assess the yield of repeat CTA for the detection of causative vascular lesions in patients with SAH in whom there has been a negative initial DSA.Material and methodsThis observational retrospective study was carried out from January 2013 to July 2022 at a single institution. Analysis of the SAH pattern on unenhanced CT showed that patients were divided into perimesencephalic SAH and diffuse SAH groups. A repeat CTA was performed on all spontaneous SAH patients who had a nega­tive initial CTA and DSA within a 2-week period. An interventional neuroradiologist and a diagnostic radiologist examined all images to search for causative vascular abnormalities.ResultsForty-seven patients were included in our study, with a median age of 55 years and a range of 28-81 years. Thirty-seven had diffuse SAH (66%), and 16 had perimesencephalic SAH (34%). The repeat CTA revealed 2 causa­tive vascular lesions (a right PICA aneurysm and a mycotic aneurysm) in 2 separate patients (yield of 4.3%), both of whom had diffuse SAH (yield of 6.5%). In retrospect, none of these vascular lesions were evident in the initial CTA and DSA. No evidence of re-bleeding was observed in the follow-up period.ConclusionsIt is beneficial to repeat CTA when evaluating patients with diffuse SAH who initially present with nega­tive initial DSA. For occult aneurysms, the diagnostic yield of the follow-up CTA is 6.5%.

Diagnostic utility of CT angiography compared with endoscopy in patients with acute GI hemorrhage