To evaluate the feasibility of dual-energy CT angiography (CTA) of the lung in patients with suspected pulmonary embolism (PE). 24 patients with suspected PE were examined with a single-acquisition, dual-energy CTA protocol (A-system: 140 kV/65 mAsref, B-system: 80kV/190 mAsref) on a dual-source CT system. Lung perfusion was visualized by color-coding voxels containing iodine and air using dedicated dual-energy postprocessing software. Perfusion defects were classified by two blinded radiologists as being consistent or non-consistent with PE. Subjective image quality of perfusion maps and CTA was rated using a 5-point scale (1: excellent, 5: poor). The reading of a third independent radiologist served as the standard of reference for the diagnosis of PE. In all patients with PE (n=4), perfusion defects classified as being consistent with PE were identified in lung areas affected by PE. Both readers did not record perfusion defects classified as being consistent with PE in any of the patients without PE. Thus, on a per patient basis the sensitivity and specificity for the assessment of PE was 100% for both readers. On a per segment basis the sensitivity and specificity ranged between 60-66.7% and 99.5-99.8%. The interobserver agreement was good (k= 0.81). Perfusion defects rated as non-consistent with PE were most frequently caused by streak artifacts from dense contrast material in the great thoracic vessels. The median score of the image quality of both the perfusion maps and CTA was 2. In conclusion, dual-energy CTA of pulmonary embolism is feasible and allows the assessment of perfusion defects caused by pulmonary embolism. Further optimization of the injection protocol is required to reduce artifacts from dense contrast material.
The objective of this study was to assess the reliability of spiral CT angiography (CTA) and 3D reconstruction in patients with aortic coarctation (CoA). Eighteen patients with suspected or surgically proven coarctation were examined by spiral CT. In addition to the axial slices, 3D reconstructions, such as shaded surface display (SSD) and maximum intensity projection (MIP), were used to determine the diameters of the CoA and the pre- and poststenotic aorta and to visualise the collateral vessels. Diameters derived from cardiac catheterization were compared with those from CTA in 8 patients. The degree of aortic stenosis was correlated with blood pressure gradients (BPG) in 12 patients. The difference between the diameters of the CoA and the pre- and poststenotic aorta derived from MIP and angiography was not statistically significant (p = 0.69). With SSD the internal thoracic artery was detected in 16 and the posterior intercostal artery in 13 cases. The degree of aortic stenosis correlated poorly with the BPG (r = 0.51, r2 = 0.26). CTA with 3D reconstruction represents a reliable noninvasive technique for the assessment of the degree of CoA and the visualisation of collateral vessels. It may serve as a follow-up investigation after intervention or surgical treatment.
ABSTRACT. Primary arteritis of the central nervous system (CNS) comprises a heterogeneous group of CNS disorders, which is characterised by non-atheromatous inflammation and necrosis of the arterial wall. The clinical presentation is highly variable, with stroke being the most common manifestation. Conventional angiography is considered to be the best imaging tool for diagnosing the disease. However, angiographic findings, which usually show lumen irregularities and stenosis, are often unspecific and can occur with a variety of other vascular disorders, such as atherosclerosis and arterial dissection. Therefore, brain biopsies are often needed to confirm the diagnosis. Recent reports have shown that MRI is able to visualise contrast enhancement in subjects with known primary CNS arteritis. This case report suggests that high-resolution contrastenhanced, black-blood T 1 weighted images with fat suppression might be useful for diagnosising intracranial arteritis. This MRI technique has the potential to replace invasive procedures, such as conventional angiography and/or brain biopsies. Furthermore, it provides information about the inflammatory activity of the disease and might be useful for monitoring anti-inflammatory therapy. Further studies are needed to confirm these initial promising results.We report the case of a 63-year-old woman with right latent hemiparesis, dysarthria, ataxia and a neuropsychological disorder with a depressive syndrome. She had suffered from a stroke affecting the pons and the left thalamus 3 months before admission to our hospital. Furthermore, the patient complained of severe and frequent headaches, and chronic fatigue. A recent oral infection with herpes simplex virus (HSV), which was treated with acyclovir, was also reported. She presented with no cardiovascular risk factors. Blood tests showed no signs of systemic inflammation. Electrocardiogram and echocardiography were normal. Duplex sonography revealed no significant stenosis in the cervical arteries, although blood flow velocity was increased in the basilar artery (85/40 cm s ). Polymerase chain reaction (PCR) for HSV, varicella zoster virus (VZV), Epstein-Barr virus (EBV) and cytomegalovirus (CMV) were negative. Serological screening for vasculitis (rheumatic factors, complement C3/C4, anti-nuclear antibody (ANA), anti-neutrophil cytoplasmic antibody (ANCA) angiotensin converting enzyme (ACE) was negative.For further diagnostic workup, the patient was referred to the radiology department for a magnetic resonance (MR) scan. All MR examinations were performed on a clinical high-field MR imager (3.0 Tesla Magnetom Verio, Siemens Healthcare, Erlangen, Germany).Time-of-flight intracranial MR angiography (Figure 1a) showed unspecific lumen irregularities in the basilar and both posterior cerebral arteries (PCA). T 2 weighted turbo spin echoes of the brain (Figure 1b) showed old ischaemic infarcts in the right and left pons and in the left thalamus. Diffusion-weighted images revealed no recent ischaemic infarction or signs of enceph...
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