Ultra-High-Resolution Time-of-Flight MR-Angiography for the Noninvasive Assessment of Intracranial Aneurysms, Alternative to Preinterventional DSA?

PURPOSE: The 3D time-of-flight (TOF) magnetic resonance angiography (MRA) at 3T shows high sensitivity for intracranial aneurysms but is inferior to three-dimensional digital subtraction angiography (3D-DSA) regarding aneurysm characteristics. We applied an ultra-high-resolution (UHR) TOF-MRA using compressed sensing reconstruction to investigate the diagnostic performance in preinterventional evaluation of intracranial aneurysms compared to conventional TOF-MRA and 3D-DSA. METHODS: In this study 17 patients with unruptured intracranial aneurysms were included. Aneurysm dimensions, configuration, image quality and sizing of endovascular devices were compared between conventional TOF-MRA at 3T and UHR-TOF with 3D-DSA as gold standard. Quantitatively, contrast-to-noise ratios (CNR) were compared between TOF-MRAs. RESULTS: On 3D-DSA, 25 aneurysms in 17 patients were detected. On conventional TOF, 23 aneurysms were detected (sensitivity: 92.6%). On UHR-TOF, 25 aneurysms were detected (sensitivity: 100%). Image quality was not significantly different between TOF and UHR-TOF (p = 0.17). Aneurysm dimension measurements were significantly different between conventional TOF (3.89 mm) and 3D-DSA (4.2 mm, p = 0.08) but not between UHR-TOF (4.12 mm) and 3D-DSA (p = 0.19). Irregularities and small vessels at the aneurysm neck were more frequently correctly depicted on UHR-TOF compared to conventional TOF. Comparison of the planned framing coil diameter and flow-diverter (FD) diameter revealed neither a statistically significant difference between TOF and 3D-DSA (coil p = 0.19, FD p = 0.45) nor between UHR-TOF and 3D-DSA (coil: p = 0.53, FD 0.33). The CNR was significantly higher in conventional TOF (p = 0.009). CONCLUSION: In this pilot study, ultra-high-resolution TOF-MRA visualized all aneurysms and accurately depicted aneurysm irregularities and vessels at the base of the aneurysm comparably to DSA, outperforming conventional TOF. UHR-TOF with compressed sensing reconstruction seems to represent a non-invasive alternative to pre-interventional DSA for intracranial aneurysms.

Single antiplatelet regimen in flow diverter treatment of cerebral aneurysms: The drug matters. A systematic review and meta-analysis.

BACKGROUND: Hemorrhagic and thromboembolic complications (TECs) are the main concerns in the endovascular treatment of intracranial aneurysms using flow diverter devices (FDs). The clinical demand for single antiplatelet therapy (SAPT) is increasing especially with the development of devices with lower thrombogenicity profile. However, the safety of SAPT is not well established. OBJECTIVE: To analyze the safety and efficacy of SAPT in terms of ischemic and hemorrhagic complications in patients undergoing FDs treatment for cerebral aneurysms. METHODS: A systematic literature search and meta-analysis were conducted in PubMed, Ovid MEDLINE, Ovid Embase, and Web of Science from January 2010 until October 2022. Twelve articles which reported SAPT and data on hemorrhagic, TECs, and mortality following FDs treatment were included. RESULTS: Overall, the 12 studies involved 237 patients with 295 aneurysms. Five investigated the safety and efficacy of SAPT in 202 unruptured aneurysms. Six studies focused on 57 ruptured aneurysms. One study included both ruptured and unruptured aneurysms. Among the 237 patients, prasugrel was most often used as SAPT in 168 cases (70.9%), followed by aspirin in 42 (17.7%) patients, and by ticagrelor in 27 (11.4%). Overall, the hemorrhagic complication rate was 0.1% (95% CI 0% to 1.8%). The TEC rate was 7.6% (95% CI 1.7% to 16.1%). In the subgroup analysis, the TEC rates of prasugrel monotherapy of 2.4% (95% CI 0% to 9.3%) and ticagrelor monotherapy of 4.2% (95% CI 0.1% to 21.1%) were lower than of aspirin monotherapy 20.2% (95% CI 5.9% to 38.6%). The overall mortality rate was 1.3% (95% CI 0% to 6.1%). CONCLUSION: According to the available data, SAPT regimen in patients undergoing FDs treatment for cerebral aneurysms has an acceptable safety profile, especially with the use of ADP-receptor antagonists.

Single-antiplatelet regimen in ruptured cerebral blood blister and dissecting aneurysms treated with flow-diverter stent reconstruction.

BACKGROUND: Flow diversion treatment of ruptured cerebral aneurysms remains challenging due to the need for double-antiplatelet therapy. We report our experience with flow-diverter stent (FDS) reconstruction with single-antiplatelet therapy of ruptured cerebral blood blister and dissecting aneurysms. METHODS: In this case series we performed a retrospective analysis of all patients with ruptured cerebral aneurysms who were treated with a phosphoryl-bonded FDS between 2019 and 2022 in a single center. Periprocedurally, all patients received weight-adapted eptifibatide IV and heparin IV. After 6-24 hours, eptifibatide was switched to oral prasugrel as monotherapy. We analyzed the rate of bleeding complications, thromboembolic events, occlusion rate and clinical outcome. RESULTS: Nine patients with subarachnoid hemorrhage were treated, eight within 24 hours of symptom onset. Seven patients were treated with one FDS and two patients received two FDS in a telescopic fashion. Two aneurysms were additionally coil embolized. Fatal re-rupture occurred in one case; eight patients survived and had no adverse events associated with the FDS. Six patients showed complete occlusion of the aneurysm after 3 months (n=2) and 1 year (n=4), respectively. Two patients showed subtotal occlusion of the aneurysm at the last follow-up after 3 months and 6 months, respectively. Favorable clinical outcome was achieved in five patients. CONCLUSIONS: Peri-interventional single-antiplatelet therapy with eptifibatide followed by prasugrel was sufficient to prevent thromboembolic events and reduce re-bleeding using an anti-thrombogenic FDS. FDS with single-antiplatelet therapy might be a viable option for ruptured blood blister and dissecting cerebral aneurysms.

Short- and Long-Term Effects of DBS on Gait in Parkinson's Disease.

The aim was to compare the short and long-term effects of subthalamic nucleus (STN) deep brain stimulation (DBS) on gait dysfunction and other cardinal symptoms of Parkinson's disease (PD). Two groups of patients were studied. The first group (short-term DBS, n = 8) included patients recently implanted with STN DBS (mean time since DBS 15.8 months, mean age 58.8 years, PD duration 13 years); the second group (long-term DBS, n = 10) included patients with at least 5 years of DBS therapy (mean time since DBS 67.6 months, mean age 61.7 years, PD duration 17.1 years). Both groups were examined using the Unified Parkinson's Disease Rating Scale (UPDRS) and Gait and Balance scale (GABS) during four stimulation/medication states (ON/OFF; OFF/OFF; OFF/ON; ON/ON). Data were analyzed using repeated measures ANOVA with time since implantation (years) between groups and medication or DBS effect (ON, OFF) within groups. In the short-term DBS group, stimulation improved all UPDRS subscores similar to dopaminergic medications. In particular, average gait improvement was over 40% (p = 0.01), as measured by the UPDRS item 29 and GABS II. In the long-term DBS group, stimulation consistently improved all clinical subscores with the exception of gait and postural instability. In these patients, the effect of levodopa on gait was partially preserved. Short-term improvement of gait abnormalities appears to significantly decline after 5 years of STN DBS in PD patients, while effectiveness for other symptoms remains stable. Progressive non-dopaminergic (non-DBS responsive) mechanisms or deleterious effects of high frequency STN stimulation on gait function may play a role.

Hemorrhagic Plaques in Mild Carotid Stenosis: The Risk of Stroke.

OBJECTIVES: Embolic ischemic strokes cause significant mortality and morbidity worldwide. It has been proposed that some of these strokes are due to unstable carotid plaques with intraplaque hemorrhage (IPH) but a low overall degree of stenosis. Our aim was to test a fat-saturated T1-weighted (T1WI) black-blood sequence on MRI for the detection of IPH in symptomatic individuals and to quantify the relation between IPH, severity of stenoses, and ischemic brain lesions. MATERIALS AND METHODS: Sixty-two patients were examined by 3T MRI. Sequences included brain diffusion-weighted imaging (DWI) as well as 3D turbo spin echo (TSE) fat-saturated black-blood T1 of the carotid bifurcations, to detect IPH as a focal intraplaque hyperintensity. Both carotid arteries were analyzed in each patient. The North American Symptomatic Carotid Endarterectomy Trial scale was used for quantification of stenosis degree. RESULTS: Thirty-six out of 62 patients (mean age, 74) showed brain ischemia on DWI. Fifteen of these 36 patients (42%) had associated ipsilateral IPH at the carotid bifurcation or the proximal internal carotid artery. Mean degree of stenosis in this group was 50%. In 21 patients with ischemia without IPH, the mean degree of stenosis was 44%. CONCLUSIONS: MRI with 3D TSE fat-saturated black-blood T1 technique is a safe, reliable, and noninvasive tool for the detection of IPH. A high percentage (42%) of ischemic events in patients with low- to moderate-degree stenosis were associated with IPH, an easily detectable imaging biomarker of plaque vulnerability. The ability to confirm IPH by MRI may help stratify patients into different risk and treatment groups in the future.

MRI of complex regional pain syndrome in the foot.

PURPOSE: To evaluate the diagnostic potential of MRI in patients with suspected CRPS (complex regional pain syndrome). METHOD: A retrospective health-record search was conducted for patients with suspected CRPS (foot). Fifty patients with initially suspected CRPS were included (37 females (51 ± 13 years) and 13 males (44 ± 15 years)). All patients underwent MRI. Two radiologists assessed skin, bone, and soft tissue parameters on MRI. The final diagnosis was CRPS (Gold standard: Budapest criteria) or non-CRPS. MRI parameters were compared between CRPS patients and non-CRPS patients. RESULTS: CRPS was diagnosed in 22/50(44 %) patients. Skin thickness (1.9 ± 0.5 mm vs. 1.7 ± 0.3 mm, p = 0.399), enhancement, and subcutaneous edema showed no differences between CRPS and non-CRPS patients. Bone marrow edema presence and pattern were not different between groups. Up to 50 % of CRPS patients showed no bone marrow edema. Subcortical enhancement and periosteal enhancement were not different between groups. For reader 1, muscle edema score was higher in the non-CRPS group compared to the CRPS group (0.1 ± 0.2 vs. 0.6 ± 1.0, p = 0.008), but not different for reader 2 (0.1 ± 0.5 vs. 0.2 ± 0.8, p = 0.819). Perfusion pattern was more extensive in non-CRPS patients for reader 1 (p = 0.048), but not for reader 2 (p = 0.157). Joint effusions showed no difference between groups. CONCLUSIONS: MRI cannot distinguish between CRPS and non-CRPS patients. The role of MR imaging in patients with suspected CRPS is to exclude alternative diagnoses that would better explain patients' symptoms.

Multivariable analysis on factors associated with aneurysm rupture in patients with multiple intracranial aneurysms.

PURPOSE: Multiple intracranial aneurysms (MIA) occur in one-third of patients with intracranial aneurysms (IA), and have been previously associated with an overall worse prognosis. Risk factors for IA formation and rupture in patients with a single IA are well-known. However, risk factors associated with rupture in patients with MIA have been less studied. METHODS: We performed a retrospective search of patients with MIA identified by computed tomography angiography (CTA) within a 10-year period. Patients with > 1 saccular aneurysm with size ≥ 2.0 mm were included. The location, size, number, and rupture status of the aneurysms were recorded. Patient demographics and cerebrovascular risk factors were obtained from electronic medical records. The primary endpoint of this study was to determine the association of these factors with aneurysmal rupture. The case-fatality rate was evaluated as a secondary outcome. RESULTS: Of the 2957 patients with IA in our CTA database, 425 patients were diagnosed with MIA and were therefore included in our study. A total of 1082 aneurysms were identified. Predictors of increased risk of aneurysmal rupture were age (OR 0.98, 95% CI, 0.96-0.99), size ≥ 5 mm (OR 4.4, 95% CI 2.76-7.0); and location in the anterior communicating artery complex (AcomC) (OR 2.62, 95% CI, 1.46-4.72) or posterior communicating artery (PCOM) (OR 2.66, 95% CI, 1.45-4.87). CONCLUSIONS: Younger age, aneurysm size ≥ 5 mm, and location in the AcomC and PCOM were independently associated with aneurysmal rupture in patients with MIA. Identifying these features could help recognize patients who might benefit from early intervention.

Accuracy of MRI T2*-weighted sequences (GRE-EPI) compared to CTA for detection of anterior circulation large vessel thrombus.

PURPOSE: Rapid detection of vessel occlusion is pivotal to the management of patients with acute stroke. Magnetic resonance (MR) T2*-weighted (W) sequence has proven its capability to detect intravascular thrombi, but its diagnostic value compared to computed tomography angiography (CTA) is not well established. We aimed to determine the diagnostic performance of fast 1.5-T MR T2*W sequences compared to CTA for the detection of intra-arterial thrombi in patients with acute stroke. METHODS: About 71 consecutive patients with known middle cerebral artery (MCA) territory stroke were identified. Patients with CTA and MR imaging within 12 h of symptom onset were included in the study. Two investigators reviewed the DWI and T2*W sequences for the presence of infarction and susceptibility vessel sign (SVS). A comparison to the corresponding internal carotid artery (ICA) and M1 and M2 segments of the MCA findings on CTA was made. RESULTS: Of the 51 patients included in our study, CTA thrombi were identified 84% patients (43/51). Of these, 77% (33/43) presented a corresponding SVS on T2*W. A total of 29 CTA thrombi were identified in the M1 segment, and of these, 22 patients had a corresponding SVS. Of the patients without M1 thrombus on CTA, no M1-SVS was detected on T2*W sequences. We found an accuracy of 92%, sensitivity of 85%, specificity of 100%, PPV 100%, and NPV of 86% for M1 occlusion. The Kappa coefficient was 0.79. CONCLUSION: Fast T2*W sequences demonstrated very good diagnostic performance and inter-reader agreement for detecting SVS in the M1 segment in patients with acute ischemic stroke.

Spot Sign in Secondary Intraventricular Hemorrhage Predicts Early Neurological Decline.

PURPOSE: The spot sign is associated with intracerebral hemorrhage (ICH) expansion and neurological decline. However, the relationship of the spot sign to secondary intraventricular hemorrhage (IVH) has not been well established. The presence of the spot sign in secondary IVH may provide information regarding neurologic outcome in a population with known poor prognosis. METHODS: A subset analysis was performed of patients with IVH from the Antihypertensive Treatment of Acute Cerebral Hemorrhage 2 (ATACH-II) study, a randomized clinical trial examining the effect of intensive blood pressure reduction on hematoma expansion. The presence of the spot sign was determined on CTA and IVH expansion was measured in the first 24 hours. The primary outcome measure was early neurological decline (END), defined as ≥ 2-point decrease in Glasgow Coma Scale (GCS) score or ≥ 4-point increase in NIH Stroke Scale (NIHSS). Secondary outcomes including various radiological and clinical factors were also measured. RESULTS: Of 57 patients included in this analysis, the spot sign was present in 17 (29.8%). The spot sign was a predictor of END in univariate (P < 0.005 for GCS and P = 0.04 for NIHSS) and multivariate analyses using GCS scores (OR=7.2, CI 1.6 - 32.5, P = 0.01). Median 90 day modified Rankin Scale (mRS) scores were significantly different between spot sign-positive and spot sign-negative groups (P = 0.02). CONCLUSIONS: The presence of the spot sign is associated with END in patients with secondary IVH. Identifying this radiologic feature could have important implications for triaging these patients to the appropriate level of care.

Vascular Imaging Techniques of the Spinal Cord.

The various imaging techniques used to depict vascular lesions of the spinal cord are described in this article with particular emphasis on magnetic resonance imaging (MRI), vascular sequences, and advantages of high-field MRI. Technical vascular protocols are discussed in computed tomography, MRI, and conventional angiography. The diverse magnetic resonance angiography protocols are presented as well as their findings, specificities, and pitfalls. A review of the vascular anatomy and the most common pathologies analyzed by magnetic resonance angiography and conventional angiography is described.

Negative spot sign in primary intracerebral hemorrhage: potential impact in reducing imaging.

Intracerebral hemorrhage (ICH) is one of the most devastating and costly diagnoses in the USA. ICH is a common diagnosis, accounting for 10-15 % of all strokes and affecting 20 out of 100,000 people. The CT angiography (CTA) spot sign, or contrast extravasation into the hematoma, is a reliable predictor of hematoma expansion, clinical deterioration, and increased mortality. Multiple studies have demonstrated a high negative predictive value (NPV) for ICH expansion in patients without spot sign. Our aim is to determine the absolute NPV of the spot sign and clinical characteristics of patients who had ICH expansion despite the absence of a spot sign. This information may be helpful in the development of a cost effective imaging protocol of patients with ICH. During a 3-year period, 204 patients with a CTA with primary intracerebral hemorrhage were evaluated for subsequent hematoma expansion during their hospitalization. Patients with intraventricular hemorrhage were excluded. Clinical characteristics and antithrombotic treatment on admission were noted. The number of follow-up NCCT was recorded. Of the resulting 123 patients, 108 had a negative spot sign and 7 of those patients subsequently had significant hematoma expansion, 6 of which were on antithrombotic therapy. The NPV of the CTA spot sign was calculated at 0.93. In patients without antithrombotic therapy, the NPV was 0.98. In summary, the negative predictive value of the CTA spot sign for expansion of ICH, in the absence of antithrombotic therapy and intraventricular hemorrhage (IVH) on admission, is very high. These results have the potential to redirect follow-up imaging protocols and reduce cost.

Isolated intraventricular haemorrhage in adults.

While intraventricular haemorrhage is frequently found in association with intraparenchymal or subarachnoid haemorrhage, isolated intraventricular haemorrhage (iIVH) is rare in adults and seldom described. Awareness of possible causes is important in order to guide patient management. After elimination of a traumatic cause, numerous aetiologies remain possible. The most frequently found underlying lesions are arteriovenous malformations and aneurysms, but other vascular causes should also be sought, including cavernous malformations and moyamoya disease. Arterial hypertension, anticoagulant use, coagulopathies and certain toxic substances are also associated with iIVH. Finally, iIVH may be caused by intraventricular tumours. In a high number of cases, the cause remains unknown. Vascular and non-vascular causes should be searched through an imaging work-up (with CT angiography, MRI and catheter angiography when necessary) and correlation with clinical information to yield a diagnosis. The aim of this pictorial essay was to review the aetiologies of iIVH in adults.

CO2BOLD assessment of moyamoya syndrome: Validation with single photon emission computed tomography and positron emission tomography imaging.

AIM: To compare the assessment of cerebrovascular reserve (CVR) using CO2BOLD magnetic resonance imaging (MRI) vs positron emission tomography (PET) and single photon emission computed tomography (SPECT) as reference standard. METHODS: Ten consecutive patients (8 women, mean age of 41 ± 26 years) with moyamoya syndrome underwent 14 pre-surgical evaluations for external-internal carotid artery bypass surgery. CVR was assessed using CO2BOLD and PET (4)/SPECT (11) with a maximum interval of 36 d, and evaluated by two experienced neuroradiologists. RESULTS: The inter-rater agreement was 0.81 for SPECT (excellent), 0.43 for PET (fair) and 0.7 for CO2BOLD (good). In 9/14 cases, there was a correspondence between CO2BOLD and PET/SPECT. In 4/14 cases, CVR was over-estimated in CO2BOLD, while in 1/14 case, CVR was underestimated in CO2BOLD. The sensitivity of CO2BOLD was 86% and a specificity of 43%. CONCLUSION: CO2BOLD can be used for pre-surgical assessment of CVR in patients with moyamoya syndrome and combines the advantages of absent irradiation, high availability of MRI and assessment of brain parenchyma, cerebral vessels and surrogate CVR in one stop.

Value of liver computed tomography with iodixanol 270, 80 kVp and iterative reconstruction.

AIM: To evaluate the image quality of hepatic multidetector computed tomography (MDCT) with dynamic contrast enhancement. METHODS: It uses iodixanol 270 mg/mL (Visipaque 270) and 80 kVp acquisitions reconstructed with sinogram affirmed iterative reconstruction (SAFIRE(®)) in comparison with a standard MDCT protocol. Fifty-three consecutive patients with known or suspected hepatocellular carcinoma underwent 55 CT examinations, with two different four-phase CT protocols. The first group of 30 patients underwent a standard 120 kVp acquisition after injection of Iohexol 350 mg/mL (Accupaque 350(®)) and reconstructed with filtered back projection. The second group of 25 patients underwent a dual-energy CT at 80-140 kVp with iodixanol 270. The 80 kVp component of the second group was reconstructed iteratively (SAFIRE(®)-Siemens). All hyperdense and hypodense hepatic lesions ≥ 5 mm were identified with both protocols. Aorta and portal vessels/liver parenchyma contrast to noise ratio (CNR) in arterial phase, hypervascular lesion/liver parenchyma CNR in arterial phase, hypodense lesion/liver parenchyma CNR in portal and late phase were calculated in both groups. RESULTS: Aorta/liver and focal lesions altogether/liver CNR were higher for the second protocol (P = 0.0078 and 0.0346). Hypervascular lesions/liver CNR was not statistically different (P = 0.86). Hypodense lesion/liver CNR in the portal phase was significantly higher for the second group (P = 0.0107). Hypodense lesion/liver CNR in the late phase was the same for both groups (P = 0.9926). CONCLUSION: MDCT imaging with 80 kVp with iterative reconstruction and iodixanol 270 yields equal or even better image quality.