Objectives To evaluate optimal monoenergetic dual-energy computed tomography (DECT) settings for artefact reduction of posterior spinal fusion implants of various vendors and spine levels. Methods Posterior spinal fusion implants of five vendors for cervical, thoracic and lumbar spine were examined ex vivo with single-energy (SE) CT (120 kVp) and DECT (140/100 kVp). Extrapolated monoenergetic DECT images at 64, 69, 88, 105 keV and individually adjusted monoenergy for optimised image quality (OPTkeV) were generated. Two independent radiologists assessed quantitative and qualitative image parameters for each device and spine level. Results Inter-reader agreements of quantitative and qualitative parameters were high (ICC00.81-1.00, κ00.54-0.77). HU values of spinal fusion implants were significantly different among vendors (P<0.001), spine levels (P<0.01) and among SECT, monoenergetic DECT of 64, 69, 88, 105 keV and OPTkeV (P<0.01). Image quality was significantly (P<0.001) different between datasets and improved with higher monoenergies of DECT compared with SECT (V 00.58, P < 0.001). Artefacts decreased significantly (V00.51, P<0.001) at higher monoenergies. OPTkeV values ranged from 123-141 keV. OPTkeV according to vendor and spine level are presented herein. Conclusions Monoenergetic DECT provides significantly better image quality and less metallic artefacts from implants than SECT. Use of individual keV values for vendor and spine level is recommended. Key Points• Artefacts pose problems for CT following posterior spinal fusion implants.• CT images are interpreted better with monoenergetic extrapolation using dual-energy (DE) CT.• DECT extrapolation improves image quality and reduces metallic artefacts over SECT.• There were considerable differences in monoenergy values among vendors and spine levels.• Use of individualised monoenergy values is indicated for different metallic hardware devices.

Neurogenic pulmonary edema (NPE), leading to cardiopulmonary dysfunction, is a potentially life-threatening complication in patients with aneurysmal subarachnoid hemorrhage (SAH). We sought to assess the clinical presentation and risk factors for the development of NPE after SAH. The database contained prospectively collected information on 477 patients with SAH. Baseline characteristics, clinical and radiologic severity of the bleeding, localization of the ruptured aneurysm, and clinical outcome of patients with NPE were compared with those of patients without NPE. Further, in patients with NPE, intracranial pressure, serum cardiac biomarkers, and hemodynamic parameters during the acute phase were evaluated retrospectively. The incidence of NPE was 8% (39 of 477 patients). Most patients with NPE were severely impaired and all of them presented with radiologically severe hemorrhage. The incidence of NPE was significantly higher in patients with ruptured aneurysm in the posterior circulation. Elevated intracranial pressure was found in 67%, pathologically high cardiac biomarkers in up to 83% of patients with NPE. However, no patient suffered from persistent cardiac dysfunction. Compared with patients without NPE, patients with NPE showed poor neurologic outcome (Glasgow outcome scale 1 to 3 in 25% vs.77% of patients). In conclusion, patients with NPE have a high mortality rate more likely due to their severity grade of the bleeding. Morbidity and mortality due to cardiopulmonary failure might be reduced by appropriate recognition and treatment. The awareness of and knowledge about occurrence, clinical presentation, and treatment of NPE, are essential for all those potentially confronted with patients with SAH in the acute phase.

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In more than half of the patients with intractable intracranial hypertension after aSAH a good functional outcome could be achieved after DHC. Patients with progressive brain edema without radiological signs of infarction and those with hematoma may benefit most. The indication for DHC should be set restrictively if secondary infarcts are manifest.

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