The use of 80 kV versus 100 kV in pulmonary CT angiography: An evaluation of the impact on radiation dose and image quality on two CT scanners.

INTRODUCTION: Use of CT in the investigation of pulmonary embolism in radiosensitive patients such as pregnant and young female patients entails the need for protocol optimization. The aim of this study was to analyze the dose reduction and image quality achieved by using 80 kV instead of 100 kV in CT pulmonary angiography protocols. METHODS: 80 examinations of non-obese patients were analyzed (40 consecutive patients for each protocol, equally distributed on two CT scanners). Objective image quality was assessed by measurements of HU values (average and standard deviation) in five ROIs in pulmonary arteries and calculations of signal-to-noise (SNR) and contrast-to-noise ratios (CNR). Subjective image quality was independently evaluated by two radiologists in terms of perceived noise, sharp reproduction of pulmonary arteries and overall diagnostic quality. Radiation dose parameters (CTDIvol, DLP, SSDE and effective dose) and effective risk were compared. Differences in radiation dose and objective measures of image quality for the two protocols were assessed using the independent t test; comparison of subjective grading of image quality was performed with the Mann-Whitney U test. RESULTS: Use of 80 kV significantly increased both arterial contrast enhancement and image noise. Differences in SNR and CNR between protocols were not statistically significant. Achieved dose reduction by using 80 kV was significant on both scanners (SSDE reduction 35% and 46%, p < 0.001; effective dose reduction 40% and 53%, p < 0.001). CONCLUSION: Use of 80 kV protocols for CT examinations of pulmonary arteries in non-obese patients with bodyweight below 80 kg results in significant reduction of radiation doses without compromising image quality.

Endovascular treatment of descending thoracic aortic disease. A single center experience.

AIM: Aim of the study was to assess if endovascular treatment is a feasible alternative in patients with descending thoracic aortic disease. METHODS: Seventy-three patients were admitted for stent-grafting of descending thoracic aortic disease during the period 1997-2008. The majority of the patients had aneurysm (35) or type B dissection (21), but also traumas, penetrating ulcers and other conditions were treated. Sixteen (22%) were unfit for open surgery. Thirty-four (47%) of the patients were symptomatic and 18 had rupture. The primary technical success rate was 96%. RESULTS: Early mortality (<30 days) for the whole group was 3%. Early endoleak (<30 days) was identified in 11 patients (15%) of whom 4 (5%) had a secondary procedure. In addition, two trauma patients required insertion of a new stent-graft due to stent-graft collapse. Two patients had stroke, one had paraplegia and two paraparesis. Mean follow-up was 3.1 years (range 0-12 years). Late endoleak (>30 days) was identified in 5 patients (7%) treated by 6 secondary procedures. One patient (1.7%) had an explant. Two patients have had extensions of endografts due to increasing diameter of the aorta at the distal end of the stent-graft. CONCLUSION: Endovascular treatment seems to be a viable alternative in patients with descending thoracic aortic disease.

DynaCT in pre-treatment evaluation of aortic aneurysm before EVAR.

OBJECTIVE: DynaCT(®) is a method for obtaining computed tomography (CT)-like images using a C-arm system. Our aim was to compare the accuracy of these images to multidetector CT (MDCT) images prior to endovascular aortic repair (EVAR). METHODS: A non-consecutive group of 20 elective patients were prospectively exposed to MDCT and one additional DynaCT before EVAR. Six arterial measurements and nine anatomical areas were chosen to: (1) visualise the peri-aortic soft tissue and assess the possibility to diagnose a potential haemorrhage from a ruptured aneurysm and (2) make the pre-treatment measurements before insertion of stent graft. Differences between modalities and readers were statistically compared using a linear mixed model. RESULTS: For maximum aortic diameter, a significant difference of 1.3 mm was found between techniques (p = 0.043). Visibility scores were significantly better for all areas in MDCT data. Pre-treatment evaluation with DynaCT before EVAR was possible for all areas; evaluation of the iliac arteries were suboptimal due to a limited imaging volume size. Significant inter-reader differences were found for all anatomical areas. CONCLUSION: The result indicates that DynaCT gives sufficient information to determine the correct treatment and for selecting the proper stent graft before EVAR. A limited volume size reduces the evaluation of the iliac arteries.

Endovascular treatment of calcified plaque in the thoracic aorta after recurrent massive embolization.

A 65 year old female patient was admitted with acute onset of severe intermittent claudication in the right lower extremity. Angiography revealed embolic material in the right femoral artery and peripheral arterial thrombosis in the right leg. She was treated with thrombolysis first, thereafter calcified embolic material was removed by open embolectomy. A CT scan showed massive calcification in the thoracic aorta at the level of the occluded left subclavian artery, obviously the origin of embolization. On the second postoperative day she developed critical ischemia in the left lower limb. Angiography showed massive embolization in the left common and external iliac arteries. Following open embolectomy, stentgrafting of the descending thoracic aorta was performed. At one year the patient is in good condition.

DynaCT during EVAR--a comparison with multidetector CT.

OBJECTIVES: We have explored the usefulness of an on-table, cross-sectional radiological imaging (DynaCT) in endovascular aortic repair (EVAR). DynaCT images were compared to images from a regular multidetector (16 slice) CT. In the comparison, we tested the accordance of firstly 5 relevant clinical measurements and secondly the visibility of 9 anatomical areas in the two different types of images. This imaging was carried out in addition to the usual angiographic imaging. DESIGN, MATERIAL AND METHOD: 20 patients with infrarenal abdominal aortic aneurysm (AAA) were prospectively enrolled in the study. We compared Images from DynaCT with two different doses of contrast medium to MDCT-images in two different ways. Firstly relevant arterial diameters and lengths and secondly, 9 anatomical areas were evaluated regarding visibility which was scored on a 4-point scale. RESULTS: There were no significant differences in the measured arterial diameters and lengths. MDCT had a significantly higher visibility score than both DynaCT investigations. However, with the highest contrast medium dose we found acceptable diagnostic quality in 78-94% of the cases for 8 of the 9 investigated anatomical areas. CONCLUSION: Our findings indicate that on-table DynaCT are of sufficient quality to give relevant information of arterial measurements, needed in endovascular repair of infrarenal aortic aneurysms.

The durability of EVAR--what are the evidence and implications on follow-up?

BACKGROUND AND AIMS: To investigate the durability of EVAR and to explore the evidence for follow-up investigations. Furthermore, to study the patients' impressions of followup investigations, and how complications and secondary procedures influence cost-effectiveness. MATERIAL AND METHODS: 263 patients were treated by EVAR from February 1995-February 2007. The series is divided into two groups with the year 2000 as a cut-off point since a new generation of stent grafts was then introduced. Early and late complications and secondary procedures were recorded. A questionnaire study was performed to investigate the patients' views on the follow-up program. RESULTS: There was a significant reduction of complications from period I to period II, which was also reflected in the reduction of secondary procedures. Freedom from secondary procedures were 47% and 93% at 5 years follow-up in the two periods, respectively. In phase II, 7.5% of the patients needed a secondary procedure. Limb extension and femoro-femoral bypass were the most common procedures. Since late complications still occur, and can be unpredictable, a follow-up program is necessary. The vast majority of the patients tolerated the follow-up program well. CONCLUSIONS: Although the number of complications following EVAR has decreased significantly over the years, a thorough follow-up program is still necessary. This followup regime is well tolerated by the patients. Reduction of secondary procedures is important to improve the cost-effectiveness of EVAR.

The inflammatory response to stent grafting of the thoracic aorta.

AIM: The aim of this study was to evaluate the inflammatory reactions in patients with thoracic aortic aneurysms before, during and after stent graft treatment and to relate markers of leukocyte activation to the use of radiographic contrast media. METHODS: Blood samples were drawn from 7 patients undergoing elective stent graft treatment for thoracic aneurysms. The samples were analyzed for leukocyte and platelet counts and the concentrations of iohexol (radiographic contrast medium), myeloperoxidase, lactoferrin, neutrophil activating peptide-2 (NAP-2), soluble intercellular adhesion molecule-1, soluble vascular cell adhesion molecule-1 (sVCAM-1), the complement activation products C3bc and the terminal complement complex (TCC). The preoperative results were compared with 10 healthy blood donors of similar age. RESULTS: Preoperatively, the aneurysm patients had significantly elevated concentrations of myeloperoxidase, neopterin and complement activation products compared to controls. Myeloperoxidase and lactoferrin increased after the first contrast dose and peaked at 8 h postoperatively. Platelet counts decreased, while NAP-2, sVCAM-1 and TCC increased from 8 h postoperatively. CONCLUSION: We conclude that patients with thoracic aneurysms have a low-grade inflammation prior to intervention. Stent graft treatment induces further activation, and markers of endothelial, platelet, and complement activation were increased for several days after the procedure. Radiographic contrast media could be an important contributor to the activation of neutrophil leukocytes.

Recovery following treatment of descending thoracic aortic disease. A comparison between endovascular repair and open surgery.

AIM: The aim of this study was to compare the postoperative course in patients treated by endovascular repair (endo) with patients treated by open surgery (open) for descending thoracic aortic disease. METHODS: Twenty-five patients treated with stent grafting for aneurysmal disease or type B dissection were compared with 35 historical controls treated by open surgery. Stay in the intensive care unit, need for artificial ventilation and to where the patient had been discharged, were noted. Pain medication, use of nasogastric tube, time until total oral nutrition, mobilization and the patients' mental condition in the postoperative period, were studied in the patients charts and the nursing reports. RESULTS: Time on the intensive care unit or intermediate care unit was median 45 h in the endo group compared with 192 h in the open group. Eighty percent of the patients in the endo group were discharged directly to their homes in contrast to 23% after open surgery. In the endo group 67% of the patients started oral nutrition on the 1st postoperative day compared to 10% in the open group. There was a significantly faster mobilization in the endo group. CONCLUSIONS: There was a significantly shorter recovery after stent grafting for descending thoracic aortic disease compared to patients operated with open surgical technique.

Ruptured abdominal aortic aneurysm secondary to tuberculous spondylitis.

A 69-year-old man was admitted with low back pain and signs of nerve root compression. A computed tomography (CT) scan showed abscess formation in the left psoas region, spondylodiscitis L3-L4 and a ruptured abdominal aortic aneurysm. The aortic aneurysm was replaced with a bifurcated vascular graft. One week later, laminectomy at the L4-level was done. In a small abscess, Mycobacterium bovis was found. The condition was considered to be a mycobacterial spondylitis secondary to BCG instillations of the urinary bladder for carcinoma. The patient received antituberculous medication for 9 months. Subsequently bone transplantation and internal fixation of the spine became necessary. Three years after surgery he is in good condition and there are no signs of graft infection on CT. Spondylitis and mycotic aortic aneurysm should be kept in mind in patients who have been treated for carcinoma of the bladder with BCG instillations.

Sensitivity of the ultrasonic CARI technique for breast tumor detection using a FETD scheme.

The CARI (clinical amplitude/velocity reconstruction imaging) technique is a new ultrasonography for better detection of the breast cancer. The method uses the mammography-like positioning of the breast and a reference structure to assess the changes of sound velocity in the screened region. In this work, we present a first attempt to simulate the CARI technique using finite element time-domain (FETD) wave propagation. The CARI sensitivity to the size, shape and location of the tumors is investigated via the simulations on 2D and 3D breast models. Small lesions can be detectable under a suitable spatial resolution. 3D simulations agree with the quantitative results of the 2D case. Moreover, the FETD approximation is proving to be a simple, but robust tool in the CARI simulation.

Three-dimensional ultrasound-based navigation combined with preoperative CT during abdominal interventions: a feasibility study.

PURPOSE: Three-dimensional (3D) intraoperative ultrasound may be easier to interpret when used in combination with less noisy preoperative image data such as CT. The purpose of this study was to evaluate the use of preoperative image data in a 3D ultrasound-based navigation system specially designed for minimally invasive abdominal surgery. A prototype system has been tested in patients with aortic aneurysms undergoing clinical assessment before and after abdominal aortic stent-graft implantation. METHODS: All patients were first imaged by spiral CT followed by 3D ultrasound scanning. The CT volume was registered to the patient using fiducial markers. This enabled us to compare corresponding slices from 3D ultrasound and CT volumes. The accuracy of the patient registration was evaluated both using the external fiducial markers (artificial landmarks glued on the patient's skin) and using intraoperative 3D ultrasound as a measure of the true positioning of anatomic landmarks inside the body. RESULTS: The mean registration accuracy on the surface was found to be 7.1 mm, but increased to 13.0 mm for specific landmarks inside the body. CT and ultrasound gave supplementary information of surrounding structures and position of the patient's anatomy. Fine-tuning the initial patient registration of the CT data with a multimodal CT to intraoperative 3D ultrasound registration (e.g., mutual information), as well as ensuring no movements between this registration and image guidance, may improve the registration accuracy. CONCLUSION: Preoperative CT in combination with 3D ultrasound might be helpful for guiding minimal invasive abdominal interventions.

The inflammatory response following treatment of abdominal aortic aneurysms: a comparison between open surgery and endovascular repair.

OBJECTIVES: to compare the inflammatory response following endovascular and conventional AAA repair. DESIGN: prospective study. PATIENTS AND METHODS: ten patients were selected for open surgery (OPEN) and ten for endovascular (ENDO) AAA repair. Leukocytes, platelets, myeloperoxidase, lactoferrin, beta-thromboglobulin, C-reactive protein (CRP), interleukin 6 (IL-6), tumour necrosis factor alpha (TNF-alpha) and complement activation products were measured before, during and after surgery. RESULTS: in the OPEN group the median hospital stay was longer (6 vs. 12 days, p=0.001) and more patients required transfusion (p=0.02). IL-6 and CRP increased postoperatively, most in OPEN (p<0.01). Platelet counts decreased after the first angiography in ENDO (p<0.01) and before aortic cross-clamping in OPEN (p<0.05). The decrease was larger in OPEN (p=0.02). Leukocyte counts decreased after the first angiography in ENDO, and thereafter increased (p=0.001). An equivalent increase was observed in OPEN after declamping (p=0.001). Leukocyte and platelet degranulation products increased after the first angiography in ENDO and after declamping in OPEN. Changes in complement activation products were small. TNF-alpha did not change significantly. CONCLUSION: endovascular AAA repair caused significant leukocyte and platelet activation. Based on the timing of activation this could be caused by radiographic contrast media.

A closed-chest pulmonary artery occlusion/reperfusion model in the pig: detection of experimental pulmonary embolism with MR angiography and perfusion MR imaging.

RATIONALE AND OBJECTIVES: To establish a pig model suitable for imitating pulmonary emboli to facilitate research in the diagnosis of pulmonary embolism. METHODS: Thirteen animals were anesthetized, mechanically ventilated, and subjected to pulmonary artery catheterization initiated from the right external jugular vein. With the use of a Swan-Ganz catheter, repetitive occlusion/reperfusion maneuvers were done at different locations of the pulmonary arterial tree. Conventional pulmonary angiography, MR angiography, and perfusion MR imaging were performed. RESULTS: The model remained hemodynamically stable throughout the 13 experiments, without any significant difference between the blood pressure measurements at the start and at the end of the right-heart and pulmonary artery catheterizations. In each of the nine animal experiments that investigated MR imaging, four of four using perfusion MR imaging (proximal and distal occlusions) and five of five using MR angiography (larger pulmonary artery occlusions), all repeated pulmonary artery occlusions were successfully performed (reproducibility of 100%). CONCLUSIONS: The closed-chest pulmonary artery occlusion/reperfusion model in the pig allowed repetitive, controlled imitations of pulmonary emboli at different levels of the pulmonary artery in the same experiment. MR angiography and perfusion MR imaging were adequate to detect the pulmonary artery occlusions and the nonperfused lung regions, respectively. The model may be a helpful tool for future research in this field.

Loss of heterozygosity at 11q23.1 in breast carcinomas: indication for involvement of a gene distal and close to ATM.

Previous reports have suggested that heterozygotes for ataxia-telangiectasia (A-T) have an increased risk of cancer, in particular breast cancer. The ATM gene, responsible for A-T, was recently cloned. Loss of heterozygosity (LOH) in the chromosome band 11q23, where the ATM gene is located, has been reported in several types of tumours including breast carcinomas. Whether the ATM gene is the target, and the sole target, for the LOH seen in this region is not yet known. In this study, 169 primary breast carcinomas and 10 metastases were examined for allelic imbalance (AI) using 10 microsatellite markers mapping to 11q23.1. Nine of the markers reside within a 10 Mb region surrounding the ATM gene, whereas the tenth locus, APOC-3, is located more than 12 Mb telomeric from this region. The highest frequencies of alteration were found for APOC-3 (45%), and for two markers located approximately 200 and 900 kb telomeric from ATM, D11S1294 (44%) and D11S1818 (44%). The marker located within the ATM gene, D11S2179, was altered in 37% of the informative tumours. The present deletion map indicates that three distinct regions at 11q23.1 may be involved in breast cancer development; one between the markers D11S1294 and D11S1818, a second close to APOC-3, and a third that is possibly the ATM-gene itself.

[Intranasal meningeal cysts]. / Intrasakrale meningeale cyster.

Intrasacral meningeal cysts are relatively uncommon. They are usually asymptomatic, but because of their expansive character, radicular symptoms or functional disturbances in the urinary bladder or rectum can occur. It is of importance to recognize these cysts in order to give the patient the correct treatment and to avoid unnecessary examinations and operations. The diagnosis can be made by myelography, computer tomography or magnetic resonance imaging.