Initial experience with a state-of-the-art mobile head CT scanner for use in neurointensive care units.

OBJECTIVE: Mobile head computed tomography (CT) scanners can reduce transport-related complications in neurointensive care unit (NICU) patients and decrease the burden on NICU staff; however, the initial investment cost and reduced image quality of early mobile scanners have prevented their widespread clinical use. Here, we report our initial experience with a novel 32-row mobile CT scanner for use in NICUs. METHODS: Over a 2-year period, 107 patients received a mobile head CT scan. The technical characteristics of the scanner and the organizational procedures are described in detail. Patient characteristics were retrospectively collected and image quality was subjectively evaluated on a Likert scale ranging from 0 to 5 and compared with a stationary CT scanner. RESULTS: Mobile head CT was used for follow-up of intracranial hemorrhage in 51%, routine postoperative imaging in 28%, evaluation of neurological deterioration in 14%, bedside monitoring after external ventricular drain placement in 4%, and follow-up of ischemic stroke in 3% of cases. Diagnostic imaging quality was achieved in all cases, eliminating the need for stationary CT scanning. The overall image quality of mobile CT (median 4 points) was inferior to that of conventional stationary CT (median 5 points, p < 0.01), but was rated with 4 or 5 points in the majority of cases. CONCLUSIONS: State-of-the-art mobile CT was found to be easy to use and maneuver and has the potential to expedite the diagnosis of NICU patients and reduce staff workload. Image quality was adequate for common NICU issues.

State-of-the-art mobile head CT scanner delivers nearly the same image quality as a conventional stationary CT scanner.

The use of mobile head CT scanners in the neurointensive care unit (NICU) saves time for patients and NICU staff and can reduce transport-related mishaps, but the reduced image quality of previous mobile scanners has prevented their widespread clinical use. This study compares the image quality of SOMATOM On.Site (Siemens Healthineers, Erlangen, Germany), a state-of-the-art mobile head CT scanner, and a conventional 64-slice stationary CT scanner. The study included 40 patients who underwent head scans with both mobile and stationary scanners. Gray and white matter signal and noise were measured at predefined locations on axial slices, and signal-to-noise ratios (SNRs) and contrast-to-noise ratios (CNRs) were calculated. Artifacts below the cranial calvaria and in the posterior fossa were also measured. In addition, image quality was subjectively assessed by two radiologists in terms of corticomedullary differentiation, subcalvarial space, skull artifacts, and image noise. Quantitative measurements showed significantly higher image quality of the stationary CT scanner in terms of noise, SNR and CNR of gray and white matter. Artifacts measured in the posterior fossa were higher with the mobile CT scanner, but subcalvarial artifacts were comparable. Subjective image quality was rated similarly by two radiologists for both scanners in all domains except image noise, which was better for stationary CT scans. The image quality of the SOMATOM On.Site for brain scans is inferior to that of the conventional stationary scanner, but appears to be adequate for daily use in a clinical setting based on subjective ratings.

Incidental finding of a bilateral absence of the superior vena cava.

Bilateral absence of the superior vena cava is associated with rhythm and structural abnormalities and is diagnosed incidentally either during imaging procedures or venous catheterization or pacemaker implantation. Knowledge of this entity is important to allow proper referral, medical management of its associated abnormalities, and risk reduction in certain interventions.

Case Report: Successful Mechanical Thrombectomy in a Newborn With Basilar Artery Occlusion.

Background: Neonatal stroke remains a rare condition that has not yet been assessed in the field of endovascular treatment. Case: We present the first case report of a successful mechanical thrombectomy in a newborn with a basilar occlusion the treatment was 14 hours after birth. Complete reperfusion of the basilar artery was achieved after the two thrombectomy maneuvers with stent retrievers. Imaging follow-up proved patency of the target vessel and at day 30, the patient showed no neurologic deficits. Conclusions: Mechanical thrombectomy appears to be technically feasible and can be an individual option in selected cases to treat stroke in neonates with proven persistent proximal cerebral artery occlusion.

Microsurgical treatment of large and giant tympanojugular paragangliomas.

BACKGROUND: Tympanojugular paragangliomas (TJPs) are benign, highly vascularized lesions located in the jugular foramen with frequent invasion to the temporal bone, the upper neck, and the posterior fossa cavity. Their natural history, surgical treatment, and outcome have been well addressed in the recent literature; however, there is no consensus regarding the optimal management while minimizing treatment-related morbidity. In this study, we assessed the interdisciplinary microsurgical treatment and outcome of large TJP collected at a single center. METHODS: Out of 54 patients with skull base paraganglioma, 14 (25%) presented with large TJP (Fisch grade C and D). Posterior fossa involvement was present in 10 patients (Fisch D). Eleven patients presented with hearing loss, two patients with mild facial nerve palsy, and two patients with lower cranial nerve deficits. Two other patients with previous surgery presented with tumor regrowth. RESULTS: Preoperative embolization was performed in 13 cases. Radical tumor removal was possible in 10 patients. Hearing was preserved in four patients with normal preoperative audiogram. The facial nerve was preserved in all patients. Temporary facial nerve palsy occurred in two patients and resolved in long-term follow-up. In three patients, preexisting facial nerve palsy remained unchanged. Persistent vocal cord palsy was present in three patients and was treated with laryngoplasty. The global recovery based on the Karnofsky performance scale was 100% in 10 patients and 90% in 4 patients. CONCLUSION: Preoperative embolization and interdisciplinary microsurgical resection are the preferred treatment for selected patients due to high tumor control rates and good long-term results.

The role of the thalamic nuclei in recognition memory accompanied by recall during encoding and retrieval: an fMRI study.

The present functional imaging study aimed at investigating the contribution of the mediodorsal nucleus and the anterior nuclei of the thalamus with their related cortical networks to recognition memory and recall. Eighteen subjects performed associative picture encoding followed by a single item recognition test during the functional magnetic resonance imaging session. After scanning, subjects performed a cued recall test using the formerly recognized pictures as cues. This post-scanning test served to classify recognition trials according to subsequent recall performance. In general, single item recognition accompanied by successful recall of the associations elicited stronger activation in the mediodorsal nucleus of the thalamus and in the prefrontal cortices both during encoding and retrieval compared to recognition without recall. In contrast, the anterior nuclei of the thalamus were selectively active during the retrieval phase of recognition followed by recall. A correlational analysis showed that activation of the anterior thalamus during retrieval as assessed by measuring the percent signal changes predicted lower rates of recognition without recall. These findings show that the thalamus is critical for recognition accompanied by recall, and provide the first evidence of a functional segregation of the thalamic nuclei with respect to the memory retrieval phase. In particular, the mediodorsal thalamic-prefrontal cortical network is activated during successful encoding and retrieval of associations, which suggests a role of this system in recall and recollection. The activity of the anterior thalamic-temporal network selectively during retrieval predicts better memory performances across subjects and this confirms the paramount role of this network in recall and recollection.

VE-PTP and VE-cadherin ectodomains interact to facilitate regulation of phosphorylation and cell contacts.

VE-cadherin is the essential adhesion molecule in endothelial adherens junctions, and the regulation of protein tyrosine phosphorylation is thought to be important for the control of adherens junction integrity. We show here that VE-PTP (vascular endothelial protein tyrosine phosphatase), an endothelial receptor-type phosphatase, co-precipitates with VE-cadherin, but not with beta-catenin, from cell lysates of transfected COS-7 cells and of endothelial cells. Co-precipitation of VE-cadherin and VE-PTP required the most membrane-proximal extracellular domains of each protein. Expression of VE-PTP in triple-transfected COS-7 cells and in CHO cells reversed the tyrosine phosphorylation of VE-cadherin elicited by vascular endothelial growth factor receptor 2 (VEGFR-2). Expression of VE-PTP under an inducible promotor in CHO cells transfected with VE-cadherin and VEGFR-2 increased the VE-cadherin-mediated barrier integrity of a cellular monolayer. Surprisingly, a catalytically inactive mutant form of VE-PTP had the same effect on VE-cadherin phosphorylation and cell layer permeability. Thus, VE-PTP is a transmembrane binding partner of VE-cadherin that associates through an extracellular domain and reduces the tyrosine phosphorylation of VE-cadherin and cell layer permeability independently of its enzymatic activity.