Simultaneous segmentation and anatomical labeling of the cerebral vasculature.

We present a novel algorithm for the simultaneous segmentation and anatomical labeling of the cerebral vasculature. Unlike existing approaches that first attempt to obtain a good segmentation and then perform labeling, we optimize for both by simultaneously taking into account the image evidence and the prior knowledge about the geometry and connectivity of the vasculature. This is achieved by first constructing an overcomplete graph capturing the vasculature, and then selecting and labeling the subset of edges that most likely represents the true vasculature. We formulate the latter problem as an Integer Program (IP), which can be solved efficiently to provable optimality. We evaluate our approach on a publicly available dataset of 50 cerebral MRA images, and demonstrate that it compares favorably against state-of-the-art methods.

Simultaneous segmentation and anatomical labeling of the cerebral vasculature.

We present a novel algorithm for the simultaneous segmentation and anatomical labeling of the cerebral vasculature. The method first constructs an overcomplete graph capturing the vasculature. It then selects and labels the subset of edges that most likely represents the true vasculature. Unlike existing approaches that first attempt to obtain a good segmentation and then perform labeling, we jointly optimize for both by simultaneously taking into account the image evidence and the prior knowledge about the geometry and connectivity of the vasculature. This results in an Integer Program (IP), which we solve optimally using a branch-and-cut algorithm. We evaluate our approach on a public dataset of 50 cerebral MRA images, and demonstrate that it compares favorably against state-of-the-art methods.

Anatomical labeling of the circle of willis using maximum a posteriori graph matching.

A new method for anatomically labeling the vasculature is presented and applied to the Circle of Willis. Our method converts the segmented vasculature into a graph that is matched with an annotated graph atlas in a maximum a posteriori (MAP) way. The MAP matching is formulated as a quadratic binary programming problem which can be solved efficiently. Unlike previous methods, our approach can handle non tree-like vasculature and large topological differences. The method is evaluated in a leave-one-out test on MRA of 30 subjects where it achieves a sensitivity of 93% and a specificity of 85% with an average error of 1.5 mm on matching bifurcations in the vascular graph.

Study of perfusion in and around cerebral contusions by means of computed tomography.

BACKGROUND: Several authors have found low absolute values of cerebral blood flow (CBF) in both contusion core and pericontusional parenchyma ofhead-injured patients by means of Xenon Computed Tomography (CT). Perfusion CT has become available as a new and validated tool for studying CBF in patients. The aim of the present study was to assess the relation between volume expansion of contusions and pericontusional CBF measured by perfusion CT. METHODS: Eight head-injured patients with a contusion on the admission CT head scan underwent a perfusion CT scan within 48 hours post trauma. The patients received standard head injury management. The eventual maximum contusion volume was assessed on the follow up plain CT scans. FINDINGS: Expansion of the contusion was observed in 6 patients. Reduced CBF was found in all contusions with absolute CBF values below 10 ml/100 g/min in the CT hyperdense/mixed density areas and below 20 ml/100 g/min in the surrounding hypodense areas. Penumbra areas, when defined by a mean transit time > 150% and cerebral blood volume > 2 ml/100 g, were limited to thin concentric rims surrounding the ischemic cores. We could not find a pattern of CBF that predicted contusion expansion. CONCLUSIONS: Based on the present preliminary data there is no indication that contusion expansion can be predicted on the basis of pericontusional CBF data.

Acquired uterine vascular malformations: radiological and clinical outcome after transcatheter embolotherapy.

The purpose of this retrospective study is to assess the radiological and clinical outcome of transcatheter embolization of acquired uterine vascular malformations in patients presenting with secondary postpartum or postabortion vaginal hemorrhage. In a cohort of 17 patients (mean age: 29.7 years; standard deviation: 4.23; range: 25-38 years) 18 embolization procedures were performed. Angiography demonstrated a uterine parenchymal hyperemia with normal drainage into the large pelvic veins ("low-flow uterine vascular malformation") in 83% (n=15) or a direct arteriovenous fistula ("high-flow uterine vascular malformation") in 17% (n=3). Clinically, in all patients the bleeding stopped after embolization but in 1 patient early recurrence of hemorrhage occurred and was treated by hysterectomy. Pathological analysis revealed a choriocarcinoma. During follow-up (mean time period: 18.8 months; range: 1-36 months) 6 patients became pregnant and delivered a healthy child. Transcatheter embolization of the uterine arteries, using microparticles, is safe and highly effective in the treatment of a bleeding acquired uterine vascular malformation. In case of clinical failure, an underlying neoplastic disease should be considered. Future pregnancy is still possible after embolization.

Hemorrhagic complications after nephron-sparing surgery: angiographic diagnosis and management by transcatheter embolization.

OBJECTIVE: Nephron-sparing surgery has become an accepted treatment technique for renal cell carcinoma in properly selected patients. Although rare, major postoperative hemorrhage can occur and is usually accompanied by gross hematuria with or without acute flank pain at the site of prior surgery. In this retrospective study, the immediate radiologic and clinical success and the long-term follow-up of transcatheter embolization are evaluated. CONCLUSION: Transcatheter selective embolization is a safe and effective technique for appropriate management of this postoperative vascular complication.

Early and long-term clinical and radiological follow-up results of expanded-polytetrafluoroethylene-covered stent-grafts for transjugular intrahepatic portosystemic shunt procedures.

The purpose of this study was to assess the therapeutic efficacy and immediate and long-term safety of expanded-tetrafluoroethylene covered stent-grafts for transjugular intrahepatic portosystemic shunts in patients with portal hypertension-related complications. A cohort of 56 patients suffering from severe portal hypertension-related complications underwent implantation of an expanded-polytetrafluoroethylene-covered stent-graft. All patients suffered from severe liver cirrhosis graded Child-Pugh A (n=8; 16%), B (n=13; 21%) or C (n=35; 63%). In 44 patients, the stent-graft was placed during the initial TIPS procedure (de novo TIPS); in the other 12 patients, the stent-graft was placed to repermeabilize the previously placed bare stent (TIPS revision). Follow-up was performed with clinical assessment, duplex ultrasound and, if abnormal or inconclusive, with invasive venography and pressure measurements. Per- en immediate post-procedural complications occurred in four patients (4/56, 7%). None of them was lethal. During follow-up, stent occlusion appeared in one patient and stenosis in two; no recurrence of bleeding was noted in all patients treated for variceal bleeding (n=28), and 24 of the 28 patients (86%) suffering from refractory ascites and/or hepatic hydrothorax were free of regular paracenteses and/or drainage of pleural effusion after shunt creation. The 30-day and global mortality for the total study population (n=56) was, respectively, 7% (n=4) and 28.5% (n=16). In the patient subgroup with variceal bleeding (n=28), 30-day mortality was 3.5% (n=1) and global mortality 14.2% (n=4). In the ascites and/or hydrothorax subgroup (n=28), 8.1% (n=3) mortality at 30 days was found and global mortality was 32.4% (n=12). In 10 patients of the 56 studied patients (18%), isolated hepatic encephalopathy occurred, which was lethal in 4 (Child C) patients (7%). Three of these four patients died within the 1st month after TIPS placement. A very high primary patency rate of TIPS can be obtained long-term after implantation of an e-PTFE-covered stent-graft, leading to a definitive resolution of portal hypertension-related complications. The incidence of TIPS-induced hepatic encephalopathy is acceptable.

Dural arteriovenous fistula as a late complication of upper cervical spine fracture. Case report.

The authors report an unusual case of a dural arteriovenous fistula (DAVF) in the cervical spine after a C1-2 fracture. The patient presented with a delayed epidural hematoma and quadriparesis. The DAVF was successfully treated by coil embolization and the patient made a full recovery. The possibility of a DAVF as a late complication of an upper cervical spine fracture should be considered when a patient presents with a spinal epidural hematoma.

Angiomatosis in the neck and mediastinum: an example of low-flow vascular malformations.

A rare case of multiple low-flow vascular malformations in the larynx, neck and mediastinum - reported as angiomatosis in the literature - is described. Sonography, CT, angiography and MRI were performed in our case, followed by laryngoscopy with biopsies to establish the diagnosis. The radiological features and a review of relevant literature are briefly discussed.

Imaging features of multifocal primary rhabdoid tumour of the central nervous system with meningeal and spinal metastases.

We present a 1-year-old boy with histologically proven multifocal rhabdoid tumour of the brain with meningeal and spinal metastasis. Although very rare and without specific radiological features, the possibility of rhabdoid tumour should be kept in mind when imaging paediatric intracranial and spinal neoplasms.

MRI demonstration of orbital lipolysis in anorexia nervosa.

The purpose of this article is to describe the orbital changes due to lipolysis in anorexia nervosa. We examined a cachectic patient with MR imaging using T1-weighted images before and after contrast enhancement. Orbital fat edema has been observed in extreme forms of cachexia and the CT and MR findings have recently been reported. The imaging appearances have been explained by the disappearance of the fat tissue and the appearance of edema due to a disturbance in the electrolyte fluid balance. In the recent literature particular attention has been paid to the increased lipid peroxidation and lipolysis in anorexia nervosa. These metabolic processes result in an increased permeability of the vessel wall endothelium, which can explain the extravasation of the contrast agent in the orbital fat on MR imaging.