RNA in extracellular vesicles during adolescence reveal immune, energetic and microbial imprints of early life adversity.

Exposure to early life adversity (ELA), including childhood maltreatment, is one of the most significant risk factors for the emergence of neuropsychiatric disorders in adolescence and adulthood. Despite this relationship being well established, the underlying mechanisms remain unclear. One way to achieve this understanding is to identify molecular pathways and processes that are perturbed as a consequence of childhood maltreatment. Ideally, these perturbations would be evident as changes in DNA, RNA or protein profiles in easily accessible biological samples collected in the shadow of childhood maltreatment. In this study, we isolated circulating extracellular vesicles (EVs) from plasma collected from adolescent rhesus macaques that had either experienced nurturing maternal care (CONT) or maternal maltreatment (MALT) in infancy. RNA sequencing of RNA in plasma EVs and gene enrichment analysis revealed that genes related to translation, ATP synthesis, mitochondrial function and immune response were downregulated in MALT samples, while genes involved in ion transport, metabolism and cell differentiation were upregulated. Interestingly, we found that a significant proportion of EV RNA aligned to the microbiome and that MALT altered the diversity of microbiome-associated RNA signatures found in EVs. Part of this altered diversity suggested differences in prevalence of bacterial species in CONT and MALT animals noted in the RNA signatures of the circulating EVs. Our findings provide evidence that immune function, cellular energetics and the microbiome may be important conduits via which infant maltreatment exerts effects on physiology and behavior in adolescence and adulthood. As a corollary, perturbations of RNA profiles related to immune function, cellular energetics and the microbiome may serve as biomarkers of responsiveness to ELA. Our results demonstrate that RNA profiles in EVs can serve as a powerful proxy to identify biological processes that might be perturbed by ELA and that may contribute to the etiology of neuropsychiatric disorders in the aftermath of ELA.

Utility of standard diffusion-weighted magnetic resonance imaging for the identification of ischemic optic neuropathy in giant cell arteritis.

This study assessed diffusion abnormalities of the optic nerve (ON) in giant cell arteritis (GCA) patients with acute onset of visual impairment (VI) using diffusion-weighted magnetic resonance imaging (DWI). DWI scans of GCA patients with acute VI were evaluated in a case-control study. Two blinded neuroradiologists assessed randomized DWI scans of GCA and controls for ON restricted diffusion. Statistical quality criteria and inter-rater reliability (IRR) were calculated. DWI findings were compared to ophthalmological assessments. 35 GCA patients (76.2 ± 6.4 years; 37 scans) and 35 controls (75.7 ± 7.6 years; 38 scans) were included. ON restricted diffusion was detected in 81.1% (Reader 1) of GCA scans. Localization of ON restricted diffusion was at the optic nerve head in 80.6%, intraorbital in 11.1% and affecting both segments in 8.3%. DWI discerned affected from unaffected ON with a sensitivity, specificity, positive and negative predictive value of 87%/99%/96%/96%. IRR for ON restricted diffusion was κinter = 0.72 (95% CI 0.59-0.86). DWI findings challenged ophthalmologic diagnoses in 4 cases (11.4%). DWI visualizes anterior and posterior ON ischemia in GCA patients with high sensitivity and specificity, as well as substantial IRR. DWI may complement the ophthalmological assessment in patients with acute VI.

Treatment of Proximal Posterior Inferior Cerebellar Artery Aneurysms by Intrasaccular Flow Disruption: A Multicenter Experience.

BACKGROUND AND PURPOSE: Treatment of PICA aneurysms can be technically challenging by either surgical or endovascular means. Our aim was to report our preliminary experience with intrasaccular flow disruption using the Woven EndoBridge (WEB) for the treatment of proximal PICA aneurysms. MATERIALS AND METHODS: Sixteen PICA aneurysms treated with the WEB at 3 institutions were retrospectively reviewed. Baseline patient and aneurysm characteristics, procedural specifics, clinical outcomes, and angiographic results were evaluated. RESULTS: All aneurysms were located at the proximal, anteromedullary segment of the PICA. Seven aneurysms were ruptured. The median aneurysm size was 3.9 mm (range, 2-12 mm), and all aneurysms were wide-neck. WEB deployment failed in 1 case due to WEB protrusion in a small PICA aneurysm. Additional stent implantation was required for 2 aneurysms to improve intra-aneurysmal WEB positioning. One patient developed a partial posterior cerebral artery territory infarction with transient hemianopsia. Intraoperative rerupture of a ruptured aneurysm could be immediately stopped by WEB deployment due to intrasaccular stasis; however, it might have contributed to a slight disability of the patient. At last angiographic follow-up, 12/15 aneurysms (80%) were completely occluded and 3/15 (20%) had a neck remnant. CONCLUSIONS: The preliminary results indicate that WEB treatment of proximal PICA aneurysms is feasible with a reasonable safety and efficacy profile. The advantages of intrasaccular flow disruption include preservation of the PICA, durable aneurysm occlusion, and omission of antiplatelet therapy. The low-profile WEB 17 delivery system might enable navigation to distal PICA aneurysms, which needs to be addressed further.

Detectability of Retinal Diffusion Restriction in Central Retinal Artery Occlusion is Linked to Inner Retinal Layer Thickness.

PURPOSE: To investigate retinal microstructure differences in central retinal artery occlusion (CRAO) patients with and without visible retinal diffusion restriction (RDR) on diffusion-weighted magnetic resonance imaging (DWI). METHODS: Consecutive CRAO patients with available optical coherence tomography (OCT) and DWI, both performed within 7 days after symptom onset, were included in a retrospective cohort study. The OCT scans were reviewed to assess retinal layer thickness, optical intensity and structural integrity. The OCT findings were compared between patients with and without visible RDR on DWI using Mann-Whitney U or Pearson's Χ2 test. RESULTS: A total of 56 patients (mean age 70.8 ± 12.8 years) were included. RDR was observed in 38 subjects (67.9%) with visually correlating low ADC map in 26 of 38 cases (68.4%). Superior and inferior parafoveal macular thickness measurements (SMT, IMT) of RDR negative patients were significantly lower when compared to RDR+ patients (370.5 ± 43.8 µm vs. 418.2 ± 76.0 µm, p = 0.016; 374.4 ± 42.9 µm vs. 428.8 ± 63.2 µm, p = 0.004) due to differences in inner retinal layer thickness (IRLT, 188.8 ± 34.4 µm vs. 234.7 ± 49.0 µm, p = 0.002). IRLT values of RDR negative patients were higher in 1.5T compared to 3T the DWI (205.0 ± 26.0 µm vs. 168.6 ± 32.8 µm, p = 0.026). CONCLUSIONS: Detectability of RDR is likely contingent upon the degree of ischemic retinal swelling in CRAO. Technical adjustments to the DWI protocol, such as increased field strength, may improve visibility of RDR.

Retinal diffusion restrictions in acute branch retinal arteriolar occlusion.

This study sought to investigate the occurrence of retinal diffusion restrictions (RDR) in branch retinal arteriolar occlusion (BRAO) using standard brain diffusion-weighted imaging (DWI). Two radiologists assessed DWI MRI scans of BRAO patients for RDR in a retrospective cohort study. Inter- and intrarater reliability were calculated using Kappa statistics. Detection rates of RDR were compared among MRI scans with varying field strength, sequence type and onset-to-DWI time intervals. 85 BRAO patients (63.1 ± 16.5 years) and 89 DWI scans were evaluated. Overall sensitivity of RDR in BRAO was 46.1% with visually correlating low ADC signal in 56.1% of cases. Localization of RDR matched distribution of fundoscopic retinal edema in 85% of patients. Inter- and intra-rater agreement for RDR in BRAO was κinter = 0.64 (95% CI 0.48-0.80) and κintra = 0.87 (95% CI 0.76-0.96), respectively. RDR detection rate tended to be higher for 3T, when compared to 1.5T MRI scans (53.7% vs. 34.3%%; p = 0.07). RDR were identified within 24 h up to 2 weeks after onset of visual impairment. RDR in BRAO can be observed by means of standard stroke DWI in a substantial proportion of cases, although sensitivity and interrater reliability were lower than previously reported for complete central retinal artery occlusion.

Time Course and Clinical Correlates of Retinal Diffusion Restrictions in Acute Central Retinal Artery Occlusion.

BACKGROUND AND PURPOSE: Retinal diffusion restrictions were recently identified as a regular finding in acute central retinal artery occlusion. We sought to investigate the influence of technical MR imaging and clinical parameters on the detection rate of retinal diffusion restrictions on standard brain DWI. MATERIALS AND METHODS: In this retrospective cohort study, MR imaging scans of patients with central retinal artery occlusion were assessed by 2 readers for retinal diffusion restrictions on DWI performed within 2 weeks after vision loss. The influence of clinical and technical MR imaging parameters and the time interval between symptom onset and DWI on the presence of retinal diffusion restrictions were evaluated. RESULTS: One hundred twenty-seven patients (mean age, 69.6 [SD 13.9] years; 59 women) and 131 DWI scans were included. Overall, the MR imaging sensitivity of retinal diffusion restrictions in acute central retinal artery occlusion was 62.6%-67.2%. Interrater and intrarater agreement for retinal diffusion restrictions was "substantial" with κinter = 0.70 (95% CI, 0.57-0.83) and κintra = 0.75 (95% CI, 0.63-0.88). Detection of retinal diffusion restrictions did not differ with differences in field strengths (1.5 versus 3T, P = .35) or sequence type (P = .22). Retinal diffusion restrictions were consistently identified within the first week with a peak sensitivity of 79% in DWI performed within 24 hours after symptom onset. Sensitivity of retinal diffusion restrictions declined in the second week (10.0%, P < .001). Absence of retinal diffusion restrictions was more prevalent in patients without fundoscopic retinal edema (60% versus 27.1%, P = .004) and with restitution of visual acuity at discharge (75% versus 28.4%, P = .006). CONCLUSIONS: Retinal diffusion restrictions in acute central retinal artery occlusion can be reliably identified on DWI performed within 24 hours and 1 week after onset of visual impairment. Detectability of retinal diffusion restrictions is dependent on the clinical course of the disease.

Standard Diffusion-weighted MRI for the Diagnosis of Central Retinal Artery Occlusion : A Case-Control Study.

PURPOSE: To evaluate diffusion abnormalities of the retina and optic nerve in patients with central retinal artery occlusion (CRAO) using standard stroke diffusion-weighted magnetic resonance imaging (DWI). METHODS: In this case-control study, DWI scans of patients with nonarteritic CRAO were retrospectively assessed for acute ischemia of the retina and optic nerve. Two neuroradiologists, blinded for patient diagnosis, randomly evaluated DWI of CRAO patients and controls (a collective of stroke and transient ischemic attack [TIA] patients) for restrictions of the retina and optic nerve. We calculated statistical quality criteria and analyzed inter-rater reliability using unweighted Kappa statistics. RESULTS: 20 CRAO patients (60,6 ± 17 years) and 20 controls (60,7 ± 17 years) were included in the study. Sensitivity, specificity, positive and negative predictive values for retinal DWI restrictions were 75%/80%/79%/76% (reader 1) and 75%/100%/100%/80% (reader 2), respectively. Unweighted Kappa was κ = 0,70 (95% CI 0,48­0,92), indicating "substantial" interrater reliability. In comparison, sensitivity, specificity, PPV and NPV (positive and negative predictive values) for restrictions of the optic nerve in CRAO were 55%/70%/65%/61% (reader 1) and 25%/100%/100%/57% (reader 2). Inter-rater reliability was "fair" with unweighted Kappa κ = 0,32 (95% CI 0,09­0,56). CONCLUSIONS: Retinal diffusion restrictions were present in a majority of CRAO patients and detectable with reasonable sensitivity, high specificity and substantial inter-rater reliability. Further studies are necessary to study time dependency of retinal diffusion restrictions, improve image quality and investigate the reliability of retinal DWI to discern CRAO from other causes of acute loss of vision.

Low-Profile Intra-Aneurysmal Flow Disruptor WEB 17 versus WEB Predecessor Systems for Treatment of Small Intracranial Aneurysms: Comparative Analysis of Procedural Safety and Feasibility.

BACKGROUND AND PURPOSE: The Woven EndoBridge 17 has recently been introduced to the market for facilitated endovascular treatment of small bifurcation aneurysms (≤7 mm) with low-profile microcatheters. We compared the Woven EndoBridge 17 with its predecessor versions in terms of procedural safety and feasibility. MATERIALS AND METHODS: This was a multicenter review of aneurysms ranging from 3 to 7 mm treated with the Woven EndoBridge between 2011 and 2019. Aneurysm characteristics, procedural parameters, and complications were retrospectively compared between treatment with the Woven EndoBridge 17 and a control group that was treated with its predecessor versions, using inverse probability of treatment weighting. RESULTS: Thirty-eight aneurysms treated with a Woven EndoBridge 17 (mean size, 4.9 ± 1.5 mm) and 70 treated with a predecessor version of the Woven EndoBridge 17 (mean size, 5.6 ± 1.4 mm) were included. The predecessor version of the Woven EndoBridge 17 had a higher failure rate (10.3%) than the Woven EndoBridge 17 (0%, P = .05). Additional stent placement was performed more often with the predecessor version of the Woven EndoBridge 17 (10.0%) than with the Woven EndoBridge 17 (2.6%, adjusted P = .005). The predecessor version of the Woven EndoBridge 17 was associated with a higher thromboembolic event rate (14.3%) than the Woven EndoBridge 17 (5.3%, adjusted P = .002). Neurologic complications (Woven EndoBridge 17: 2.6%; predecessor version of the Woven EndoBridge 17: 2.9%, adjusted P = 1.0) and immediate complete aneurysm occlusion rates (Woven EndoBridge 17: 57.9%; predecessor version of the Woven EndoBridge 17: 54.3%, adjusted P = .21) did not differ significantly between groups. CONCLUSIONS: In the current study, the Woven EndoBridge 17 was associated with a potentially lower thromboembolic event rate than the predecessor version of the Woven EndoBridge 17, without compromising the immediate aneurysm occlusion rate. Long-term clinical and angiographic outcome analysis will be necessary to draw a definite conclusion.

Discharge status and in-hospital mortality in posterior reversible encephalopathy syndrome.

BACKGROUND: Posterior reversible encephalopathy syndrome is a serious and increasingly recognized disorder, but data from observational studies on outcome and mortality in posterior reversible encephalopathy syndrome (PRES) are scarce. We aimed to determine the frequency and associations of in-hospital death and discharge status in a large cohort of patients with PRES. METHOD: We retrospectively reviewed the radiological report databases of our university hospitals between January 1999 and March 2011 for patients with PRES. Patients fulfilling the criteria for PRES after detailed investigation of clinical charts and imaging studies were included. Clinical charts, paraclinical and brain imaging data at onset as well as available data on in-hospital mortality and discharge status were analyzed. RESULTS: A total of 103 patients were included. Five (4.8%) patients died during hospital stay, 27 (26.2%) remained hospitalized after discharge. In univariate analyses, significant differences were found between patients discharged home from hospital and patients referred to rehabilitation or who died in hospital for the following variables: severe edema (P = 0.013), etiology of PRES (P = 0.001), altered mental state at onset (P = 0.003), altered coagulation (P = 0.004), and length of hospital stay >30 days (P < 0.001). CONCLUSION: Features of a severe course of PRES such as severe edema and altered mental state are significantly more frequent in patients who were referred to inpatient rehabilitation or died in hospital. Prospective studies are warranted to establish factors that are associated with unfavorable outcome in PRES.

Posterior reversible encephalopathy syndrome in children: radiological and clinical findings - a retrospective analysis of a German tertiary care center.

PURPOSE: To report the radiological and clinical spectrum of posterior reversible encephalopathy syndrome (PRES) in children in a German tertiary referral center. METHODS: The radiological report data bases of the authors' university hospitals were searched for paediatric patients with PRES. Clinical and paraclinical data as well as various imaging features at symptom onset and during follow-up were tabulated in patients fulfilling the criteria for PRES. RESULTS: A total of 18 paediatric patients with PRES were included into the study. Mean age was 9 years (IQR 7-12), 38.9% were females. Most frequent predisposing causes were renal and haemato-oncologic diseases frequently associated with endotheliotoxic cytostatic medication. Frontal lesions occurred as frequently as parietal lesions followed by occipital lesions. The superior frontal sulcus topographic lesion pattern occurred as frequent as the parieto-occipital one. In 38% of cases residual lesions were encountered with focal laminar necroses being most frequent. Initial clinical syndromes associated with PRES included seizures in 18, altered mental state in 5, and hemiparesis and visual disturbances in 2 children. Mean arterial blood pressure at onset of PRES was 140/85 mmHg (IQR systolic: 124-169, diastolic: 78-93 mmHg). CONCLUSION: Paediatric PRES in this cohort comprises a broad radiological and clinical spectrum. The occurrence of frontal lesions, a superior frontal sulcus associated lesion pattern, and the development of focal laminar necrosis appear to be frequent in children.

Clinical and radiological differences in posterior reversible encephalopathy syndrome between patients with preeclampsia-eclampsia and other predisposing diseases.

BACKGROUND: Posterior reversible encephalopathy syndrome (PRES) is a serious maternal complication in pregnancy, but data on the clinicoradiological differences to other etiologies of PRES are scarce. In this study, we aimed to investigate the clinical and imaging characteristics of PRES in preeclampsia-eclampsia patients compared with other predisposing diseases in a large cohort. METHODS: We retrospectively reviewed the radiological report data bases between January 1999 and August 2010 for patients with PRES. Patients fulfilling the criteria for PRES after detailed investigation of clinical charts and imaging studies were separated into patients with eclampsia-preeclampsia and other predisposing causes. Various imaging features at onset of symptoms and on follow-up as well as clinical and paraclinical data were analyzed. RESULTS: A total of 24 patients with preeclampsia-eclampsia associated PRES and 72 patients with PRES of other predisposing causes were included into the study. In preeclampsia-eclampsia patients, headaches were significantly more frequent as initial PRES-related symptom (P < 0.001), whereas altered mental state was significantly less frequent (P = 0.001). Thalamus, midbrain, and pons affection was significantly less frequent in preeclampsia-eclampsia associated PRES (P = 0.01). Preeclampsia-eclampsia patients had significantly less severe edema, less cytotoxic edema, hemorrhage and contrast enhancement, while more frequent complete resolution of edema and less frequent residual structural lesions were seen on follow-up imaging. CONCLUSION: In our PRES cohort, we found major clinicoradiological differences between preeclampsia-eclampsia and other predisposing causes pointing toward a less severe course of disease in preeclampsia-eclampsia.

The clinical and radiological spectrum of posterior reversible encephalopathy syndrome: the retrospective Berlin PRES study.

The aim of the study was to characterize the clinical and radiological spectrum of posterior reversible encephalopathy syndrome (PRES) in a large cohort. The radiological report data bases of the authors' university hospitals were searched for patients with PRES. Various imaging features at onset of symptoms and on follow-up as well as clinical and paraclinical data were tabulated in those patients fulfilling the criteria for PRES. Exploratory univariate analyses were performed. A total of 96 patients with PRES were included into the study. Wide differences in lesion location, diffusivity, distribution pattern, edema severity, hemorrhage, underlying diseases, symptoms, mean arterial pressure (MAP) and coagulation status were encountered. Hemorrhage occurred significantly more frequently in patients with altered coagulation state and was significantly associated with higher edema grades and with the presence of cytotoxic edema. There was a significant difference in MAP between toxic associations with higher MAP in infection, eclampsy and autoimmune disorders, while lower MAP was found in chemotherapy and immunsupression. In 82% of patients complete or near complete resolution of edema was noted during follow-up. Higher MAP levels were associated with incomplete edema resolution. In 43% of patients residual lesions were seen with a relatively even distribution between focal gliosis, infarction, posthemorrhagic residua, atrophy and laminar necrosis. PRES in this large hospital-based retrospective study comprises a wide radiological and clinical spectrum. Residual lesions were encountered more frequently than commonly expected. Our results point towards a differential contribution of high blood pressure to the course of PRES in different underlying etiologies.

Image quality and radiation exposure in 320-row temporal bone computed tomography.

OBJECTIVES: The aim was to define image quality and radiation exposure in the recently introduced 320-row CT of the temporal bone (tb) in comparison to a 16-row tb CT. METHODS: A cadaveric head phantom was used for repeated tb volume CT studies (80-120 kV, 25-150 mAs), performed in a 320-row scanner (single rotation, 0.5 mm slice thickness, kernel FC 51) in comparison to 16-row helical CT using standard acquisition parameters (SAP) of 120 kV and 75 mAs (kernel FC 53). Qualitative image evaluation was performed by two radiologists using a 5-point visual analogue scale. Image noise (D(SD)) was determined by region of interest (ROI) based measurements in cadaveric as well as water phantom studies. Dosimetric measurements of the effective dose (ED) and organ dose (OD) of the lens were performed. RESULTS: Image quality of 320-row tb CT was equivalent to 16-row CT for SAP scans, resulting in image noise levels (D(SD) 16-/320-row) of 109/237 and 206/446 for air and bone respectively. D(SD) differences were predominantly (>90%) attributable to the different kernels available for tb studies in 16- and 320-row CT. Radiation exposure for 16-/320-row SAP scans amounted to 0.36/0.30 mSv (ED) and 10.0/8.4 mGy (lens dose). CONCLUSION: 320-row volume acquisition in tb CT delivers equivalent image quality to 16-row CT while decreasing radiation exposure figures by one sixth. Image noise increase in 320-row CT is negligible with respect to image quality.

[Headache and hypertension. Myth and evidence]. / Kopfschmerz und Bluthochdruck. Mythos und Evidenz.

The relationship between headache and hypertension has been debated for many years. Although most studies have shown that chronic hypertension and headache are not associated, the myth of a hypertensive headache still exists. There are several reasons why the "hypertension headache" misperception persists: Hypertension is an epiphenomenon of pain. Headache is a common side effect of some antihypertensive drugs. Headache is the most common presenting symptom of hypertensive encephalopathy, followed by seizures, focal neurological deficits and loss of consciousness. This review summarizes the existing literature and highlights the relationship between headache, hypertension and disease with a focus on hypertensive encephalopathy and posterior reversible encephalopathy syndrome with acute endothelial damage.

Infectious vasculopathy of intracranial large- and medium-sized vessels in neurological intensive care unit: a clinico-radiological study.

BACKGROUND: Infections are a well-known cause of cerebral vasculopathy and vasculitis. We aimed to analyze the frequency of intracranial vasculopathy attributable to infection, the spectrum of causative microorganisms, imaging, and cerebrospinal fluid (CSF) characteristics as well as clinical course and outcome. METHODS: We used our institution's medical record system to identify all patients diagnosed with nonatherosclerotic central nervous system vasculopathy from January 1, 1999 through February 28, 2009. We reviewed their clinical charts, imaging data, and results of CSF studies. RESULTS: Twenty-five adult patients with nonatherosclerotic cerebral vasculopathy of large- and medium-sized intracranial vessels were identified. Eight patients had vasculopathy attributable to infection (32%). The underlying pathologies were acute bacterial meningitis (n = 4), varicella zoster virus (VZV) infection (n = 2), borreliosis (n = 1), and syphilis (n = 1). In six patients, magnetic resonance angiography was performed and showed vasculopathic changes in all patients examined (100%). In both patients with VZV-associated vasculopathy, the arterial wall enhanced on magnetic resonance imaging. The CSF examination of the patients with infectious vasculopathy showed a significantly higher white blood cell count. The outcome of the infectious cohort was unfavorable with one death, two patients with locked-in syndrome, and five patients discharged from intensive care with severe neurological deficits. CONCLUSION: In this cohort, one-third of all cases of nonatherosclerotic vasculopathy were due to infectious vasculopathy of large and medium intracranial vessels.

Dose exposure of patients undergoing comprehensive stroke imaging by multidetector-row CT: comparison of 320-detector row and 64-detector row CT scanners.

BACKGROUND AND PURPOSE: Recently introduced 320-detector row CT enables whole brain perfusion imaging compared to a limited scanning area in 64-detector row CT. Our aim was to evaluate patient radiation exposure in comprehensive stroke imaging by using multidetector row CT consisting of standard CT of the head, CTA of cerebral and cervical vessels, and CTP. MATERIAL AND METHODS: Organ doses were measured by using LiF-TLDs located at several organ sites in an Alderson-Rando phantom. Effective doses were derived from these measurements. Stroke protocols including noncontrast head CT, CTA of cerebral and cervical vessels, and CTP were performed on 320- and 64-detector row scanners. RESULTS: Measured effective doses for the different scanning protocols ranged between 1.61 and 4.56 mSv, resulting in an effective dose for complete stroke imaging of 7.52/7.54 mSv (m/f) for 64-detector row CT and 10.56/10.6 mSv (m/f) for 320-detector row CT. The highest organ doses within the area of the primary beam were measured in the skin (92 mGy) and cerebral hemispheres (69.91 mGy). Use of an eye-protection device resulted in a 54% decrease of the lens dose measured for the combo protocol for whole-brain perfusion with the 320-detector row CT scanner. CONCLUSIONS: Phantom measurements indicate that comprehensive stroke imaging with multidetector row CT may result in effective radiation doses from 7.52 mSv (64-detector row CT) to 10.6 mSv (320-detector row CT). The technique of 320-detector row CT offers additional information on the time course of vascular enhancement and whole-brain perfusion. Physicians should weigh the potential of the new technique against the higher radiation dose that is needed. Critical doses that would cause organ damage were not reached.

Dose related, comparative evaluation of a novel bone-subtraction algorithm in 64-row cervico-cranial CT angiography.

PURPOSE: Comparative evaluation of a low-dose scan protocol for a novel bone-subtraction (BS) algorithm, applicable to 64-row cervico-cranial (cc) CT angiography (MSCTA). METHODS AND PATIENTS: BS algorithm assessment was performed in cadaveric phantom studies by stepwise variation of tube current and head malrotation using a 64-row CT scanner. In order to define minimum dose requirements and the rotation correction capacity, a low dose BS MSCTA protocol was defined and evaluated in 12 patients in comparison to a common manual bone removal algorithm. Standard MIPs of both modalities were evaluated in a blinded manner by two neuroradiologists for image quality composed, of vessel contour sharpness and bony vessel superposition, by using a five-point score each. Effective Dose (E) and data post-processing times were defined. RESULTS: In experimental studies prescan tube current could be cut down to one-sixth of post-contrast scan doses without compromise of bone-subtraction whereas incomplete subtraction appeared from four degrees head malrotation on. Prescan E amounted to additional 1.1mSv (+25%) in clinical studies. BS MSCTA performed significantly superior in terms of bony superposition for vascular segments C3-C7 (p<0.001), V1-V2, V3-V4 (p<0.05, p<0.001 respectively) and the ophthalmic artery (p<0.05), whereas vessel contour sharpness in BS MSCTA only proved superior for arterial segments V3-V4 (p<0.001) and C3-C7 (p<0.001). MBR MSCTA received higher ratings in vessel contour sharpness for C1-C2 (p<0.001), callosomarginal artery (p<0.001), M1, M2, M3 (p<0.001 each) and the basilar artery (p<0.001). Reconstruction times amounted to an average of 1.5 (BS MSCTA) and 3min (MBR MSCTA) respectively. CONCLUSION: The novel BS algorithm provides superior skull base artery visualisation as compared to common manual bone removal algorithms, increasing the Effective Dose by one-fourth. Yet, inferior vessel contour sharpness was noted intracranially, thus limiting the BS algorithm use to patients with suspected vessel pathology at the skull base level.