Initial steps towards automatic segmentation of the wire frame of stent grafts in CT data

For the purpose of obtaining a geometrical model of the wire frame of stent grafts, we propose three tracking methods to segment the stent's wire, and compare them in an experiment. A 2D test image was created by obtaining a projection of a 3D volume containing a stent. The image was modified to connect the parts of the stent's frame and thus create a single path. Ten versions of this image were obtained by adding different noise realizations. Each algorithm was started at the start of each of the ten images, after which the traveled paths were compared to the known correct path to determine the performance. Additionally, the algorithms were applied to 3D clinical data and visually inspected. The method based on the minimum cost path algorithm scored excellent in the experiment and showed good results on the 3D data. Future research will focus on establishing a geometrical model by determining the corner points and the crossings from the results of this method.\u

Impact of dynamic computed tomographic angiography on endograft sizing for endovascular aneurysm repair.

Contains fulltext : 80349.pdf (publisher's version ) (Open Access)PURPOSE: To quantify dynamic changes in aortoiliac dimensions using dynamic electrocardiographically (ECG)-gated computed tomographic angiography (CTA) and to investigate any potential impact on preoperative endograft sizing in relation to observer variability. METHODS: Dynamic ECG-gated CTA was performed in 18 patients with abdominal aortic aneurysms. Postprocessing resulted in 11 datasets per patient: 1 static CTA and 10 dynamic CTA series. Vessel diameter, length, and angulation were measured for all phases of the cardiac cycle. The differences between diastolic and systolic aneurysm dimensions were analyzed for significance using paired t tests. To assess intraobserver variability, 20 randomly selected datasets were analyzed twice. Intraobserver repeatability coefficients (RC) were calculated using Bland-Altman analysis. RESULTS: Mean aortic diameter at the proximal neck was 21.4+/-3.0 mm at diastole and 23.2+/-2.9 mm at systole, a mean increase of 1.8+/-0.4 mm (8.5%, p<0.01). The RC for the aortic diameter at the level of the proximal aneurysm neck was 1.9 mm (8.9%). At the distal sealing zones, the mean increase in diameter was 1.7+/-0.3 mm (14.1%, p<0.01) for the right and 1.8+/-0.5 mm (14.2%, p<0.01) for the left common iliac artery (CIA). At both distal sealing zones, the mean increase in CIA diameter exceeded the RC (10.0% for the right CIA and 12.6% for the left CIA). CONCLUSION: The observed changes in aneurysm dimension during the cardiac cycle are small and in the range of intraobserver variability, so dynamic changes in proximal aneurysm neck diameter and aneurysm length likely have little impact on preoperative endograft selection. However, changes in diameter at the distal sealing zones may be relevant to sizing, so distal oversizing of up to 20% should be considered to prevent distal type I endoleak

Local and systemic thrombolytic therapy for acute deep venous thrombosis.

Contains fulltext : 48677.pdf (publisher's version ) (Open Access)This article presents a review of the treatment of lower-extremity deep venous thrombosis (DVT) with systemic and catheter-directed thrombolysis (CDT) and percutaneous mechanical thrombectomy (PMT). Standard treatment including anticoagulation therapy and compression stockings may not be entirely adequate, because a significant proportion of patients eventually develop post-thrombotic syndrome (PTS). Thrombolytic agents might offer a potential advantage because they cause faster and more complete clot resolution, which may reduce or prevent residual vein stenosis and valve damage. Thrombolytic therapy results in greater lysis, but also in higher complication rates than does anticoagulation alone. Major bleeding occurs in 11% of patients treated with thrombolytic therapy. The incidence of PTS tends to be lower in patients treated with thrombolytics. However, several methodological flaws limit the conclusions with respect to reduction in PTS. No adequate randomised controlled trials have been performed comparing CDT or PMT with conventional therapy. Given the current data, thrombolytic treatment, CDT or PMT should not be applied except in extraordinary cases. First, the long-term effectiveness in terms of reducing PTS, although possible, remains uncertain. Second, the risks of thrombolytic therapy and PMT are higher. Third, current conventional therapy is relatively inexpensive, convenient and safe

Aspiration sclerotherapy combined with pasireotide to improve reduction of large symptomatic hepatic cysts (SCLEROCYST): study protocol for a randomized controlled trial

Contains fulltext : 154569.pdf (publisher's version ) (Open Access)BACKGROUND: Aspiration sclerotherapy is an effective therapeutic option for large symptomatic hepatic cysts. However, incomplete cyst reduction following aspiration sclerotherapy is frequently reported. Strong post-procedural cyst fluid secretion by cholangiocytes, which line the epithelium of the hepatic cyst, seems to be associated with lower reduction rates. Previous studies showed that somatostatin analogues curtail hepatic cyst fluid production. This trial will evaluate the effect of aspiration sclerotherapy combined with the somatostatin analogue pasireotide on cyst reduction. By combining treatment modalities we aim to improve cyst reduction leading to greater symptomatic relief and reduced rates of cyst recurrence. METHODS/DESIGN: This single center, randomized, double-blind, placebo-controlled clinical trial evaluates the additional effect of pasireotide when combined with aspiration sclerotherapy in patients with a large (>5 cm) symptomatic hepatic cyst. A total of 34 participants will be randomized in a 1:1 ratio. In the active arm, patients will receive pasireotide (long-acting release, 60 mg injection) two weeks prior to and two weeks following aspiration sclerotherapy. Patients in the control arm will receive placebo injections at corresponding intervals. The primary outcome is proportional cyst diameter reduction four weeks after aspiration sclerotherapy compared to baseline measurements, obtained by ultrasonography. As secondary outcomes, proportional volume reduction, recurrence, symptomatic relief and improvement of health-related quality of life will be assessed. Furthermore, safety and tolerability of the combination of pasireotide and aspiration sclerotherapy will be evaluated. DISCUSSION: This trial aims to improve efficacy of aspiration sclerotherapy by a combined approach of two treatment modalities. We hypothesize that pasireotide will decrease fluid re-accumulation after aspiration sclerotherapy, leading to effective hepatic cyst reduction and symptomatic relief. TRIALS REGISTRATION: This trial is registered with ClinicalTrials.gov (identifier: NCT02048319 ; registered on 6 January 2014) and EudraCT (identifier: 2013-003168-29; registered on 16 August 2013)

Displaying inguinal lymph nodes before transplantation in a deep inferior epigastric perforator flap breast reconstruction using an innovative projection method

Item does not contain fulltextINTRODUCTION: Lymphedema of the arm is a common postoperative complication as a result of breast cancer surgery. One of the surgical treatments comprises modification of a deep inferior epigastric perforator (DIEP) flap breast reconstruction to facilitate additional lymph node transplantation from the inguinal area. Using computed tomography angiography (CTA), the distribution of these lymph nodes can be assessed. A virtual planning based on this CTA created for the DIEP flap is presented, with the inguinal lymph nodes included, followed by preoperatively projecting this information on the patient's abdomen. METHODS: A total of 10 patients underwent the standard imaging protocol: A preoperative CTA to assess the vascular anatomy of the lower abdomen. A three-dimensional (3D) model of the blood vessels was produced, and the inguinal lymph nodes in this reconstruction were included. Preoperative projection of the 3D model onto the patients' abdomen and inguinal area was performed, followed by tracing of this image. Intraoperatively found lymph nodes were identified by touch and compared with the markings on the skin. RESULTS: In all 10 patients, all lymph nodes located preoperatively were found intraoperatively within a 1-cm radius of the marking on the skin; and these were more easily located by two operating surgeons. CONCLUSION: Virtual planning of lymph node transplantations in a deep inferior epigastric artery perforator flap breast reconstruction seems feasible and can be performed quickly. This additional visual support aids the surgeon in locating the lymph nodes in the inguinal area

An unexpected outcome of cervical near-hanging injury. A case report.

Contains fulltext : 88142.pdf (publisher's version ) (Open Access)Cervical near-hanging injuries are most frequent in the young adult population. However, the literature gives little guidance regarding diagnostic evaluation of these patients, although it is well known that their initial clinical presentation has limited prognostic value. This case report presents a patient who actually survived a suicidal near-hanging attempt and was later able to walk and talk to his physician. He died the next day due to carotid dissection and cerebral ischemia. In this case report we emphasize the importance of thorough radiological investigation in the accurate assessment of these patients. Early imaging should be performed routinely after near-hanging injury, in order to establish the correct diagnosis and allow appropriate treatment to be started

A Segmentation Method for Stentgrafts in the Abdominal Aorta from ECG-gated CTA Data

Endovascular aortic replacement (EVAR) is an established technique, which uses stentgrafts to treat aortic aneurysms in patients at risk of aneurysm rupture. The long-term durability of a stentgraft is affected by the stresses and hemodynamic forces applied to it, and may be reflected by the movements of the stentgraft itself during the cardiac cycle. A conventional CT scan (which results in a 3D volume) is not able to visualize these movements. However, applying ECG-gating does provide insight in the motion of the stentgraft caused by hemodynamic forces at different phases of the cardiac cycle. The amount of data obtained is a factor of ten larger compared to conventional CT, but the radiation dose is kept similar for patient safety. This causes the data to be noisy, and streak artifacts are more common. Algorithms for automatic stentgraft detection must be able to cope with this. Segmentation of the stentgraft is performed by examining slices perpendicular to the centreline. Regions with high CT-values exist at the locations where the metallic frame penetrates the slice. These regions are well suited for detection and sub-pixel localization. Spurious points can be removed by means of a clustering algorithm, leaving only points on the contour of the stent. We compare the performance of several different point detection methods and clustering algorithms. The position of the stent’s centreline is calculated by fitting a circle through these points. The proposed method can detect several stentgraft types, and is robust against noise and streak artifacts

In-vivo imaging of changes in abdominal aortic aneurysm thrombus volume during the cardiac cycle.

Contains fulltext : 80262.pdf (publisher's version ) (Open Access)PURPOSE: To evaluate in-vivo thrombus compressibility in abdominal aortic aneurysms (AAAs) to hopefully shed light on the biomechanical importance of intraluminal thrombus. METHODS: Dynamic electrocardiographically-gated computed tomographic angiography was performed in 17 AAA patients (15 men; mean age 73 years, range 69-76): 11 scheduled for surgical repair and 6 under routine surveillance. The volumes of intraluminal thrombus, the lumen, and the total aneurysm were quantified for each phase of the cardiac cycle. Thrombus compressibility was defined as the percent change in thrombus volume between diastole and peak systole. Continuous data are presented as medians and interquartile ranges (IQR). RESULTS: A substantial interpatient variability was observed in thrombus compressibility, ranging from 0.4% to 43.6% (0.2 to 13.5 mL, respectively). Both thrombus and lumen volumes varied substantially during the cardiac cycle. As lumen volume increased (5.2%, IQR 2.8%-8.8%), thrombus volume decreased (3.0%, IQR 1.0%-4.6%). Total aneurysm volume remained relatively constant (1.3%, IQR 0.4-1.9%). Changes in lumen volume were inversely correlated with changes in thrombus volume (r = -0.73; p = 0.001). CONCLUSION: In-vivo thrombus compressibility varied from patient to patient, and this variation was irrespective of aneurysm size, pulse pressure, and thrombus volume. This suggests that thrombus might act as a biomechanical buffer in some, while it has virtually no effect in others. Whether differences in thrombus compressibility alter the risk of rupture will be the focus of future research