Biomechanical changes of the common carotid artery and internal jugular vein in patients with multiple sclerosis.

PURPOSE: Investigations of the hemodynamic changes of the venous system in patients with multiple sclerosis (MS) have shown contradictory results. Herein, the biomechanical parameters of the internal jugular vein (IJV) and common carotid artery (CCA) of MS patients were extracted and compared to healthy individuals. METHODS: B-mode and Doppler sequential ultrasound images of 64 IJVs and CCAs of women including 22 healthy individuals, 22 relapsing-remitting multiple sclerosis (RRMS) patients, and 20 primary-progressive multiple sclerosis (PPMS) patients were recorded and processed. The biomechanical parameters of the IJV and the CCA walls during three cardiac cycles were calculated. RESULTS: The IJV maximum and minimum pressures were higher in the MS patients than in the healthy subjects, by 31% and 19% in RRMS patients and 39% and 24% in PPMS patients. The venous wall thicknesses in RRMS and PPMS patients were 51% and 60% higher than in healthy subjects, respectively. IJV distensibility in RRMS and PPMS patients was 70% and 75% lower, and compliance was 40% and 59% lower than in healthy subjects. The maximum intima-media thicknesses of the CCAs were 38% and 24%, and the minimum intima-media thicknesses were 27% and 23% higher in RRMS and PPMS patients than in healthy individuals, respectively. The shear modulus of CCA walls in RRMS and PPMS patients was 17% and 31%, and the radial elastic moduli were 47% and 9% higher than in healthy individuals. CONCLUSION: Some physical and biomechanical parameters of the CCA and IJV showed significant differences between MS patients and healthy individuals.

Anastomotic biliary stricture following liver transplantation and management analysis: 15 years of experience at a high-volume transplant center.

INTRODUCTION: The occurrence of anastomotic biliary stricture (BS) remains an essential issue following liver transplantation (LT). The present study aimed to compare our findings regarding the incidence of anastomotic BS to what is known. METHODS: The present study is a single-center, retrospective cohort study of a total number of 717 consecutive patients (426 men and 291 women) who had undergone LT from January 2001 to March 2016. Multivariable Cox regression analysis was conducted to evaluate the risk factors associated with anastomotic BS development. RESULTS: Post-transplant anastomotic BS developed in 70 patients (9.8%). In the Cox multivariate analysis (a stepwise forward conditional method), factors including biliary leak (hazard ratio [HR]: 6.61, 95% confidence interval [CI]: 3.08-17.58, p < 0.001), hepatic artery thrombosis (HR: 2.29, 95% CI: 1.03-5.88; p = 0.003), and acute rejection (HR: 2.18, 95% CI: 1.16-3.37; p = 0.006) were identified as independent risk factors for the development of anastomotic BS. Surgery in 6 cases (66.7%), followed by endoscopic retrograde cholangiopancreatography (ECRP) with a metal stent in 18 cases (62.1%), percutaneous transhepatic biliary drainage in 9 (20.9%), and ERCP with a single plastic stent in 8 (18.2%), had the highest effectiveness rates in the management of BS, respectively. CONCLUSIONS: Risk factors including biliary leak, hepatic artery thrombosis, and acute rejection were independently associated with an anastomotic BS. ERCP with a metal stent may be considered as an effective treatment procedure with a relatively low complication rate in the management of benign post-LT anastomotic BS.

Assessing the short-term effects of radiotherapy on the shear modulus of the common carotid artery as a new biomarker of radiation-induced atherosclerosis.

PURPOSE: The purpose of this study was to investigate the incidence of short-term atherosclerosis in the common carotid arteries following radiotherapy. METHODS: The mean radiation dose to the arteries was 49.30±15.83 Gy. A computational ultrasound method was introduced to investigate the elastic modulus. Ultrasonography was performed 2-3 cm inferior to the bifurcation region before and after radiotherapy, and sequential images were extracted from a video of each artery. Instantaneous movement of the arterial wall in the radial and longitudinal directions was extracted by implementing the maximum gradient and block matching algorithms, respectively. RESULTS: There was a significant change in systolic blood pressure after radiotherapy (P=0.008). Irradiated arteries had significantly smaller systolic and end-diastolic diameters than non-irradiated arteries (P<0.001). The shear modulus was significantly different between irradiated and non-irradiated arteries (3.10±2.03 kPa vs. 1.38±0.98 kPa, P<0.001). The shear and Young moduli of radiation-induced arteries were 2.25±1.50 and 1.57±0.59 times higher than those of the pre-irradiation arteries. CONCLUSION: The arterial shear modulus can be considered as a new biomarker of radiationinduced atherosclerosis in the common carotid artery.

Stress distribution analysis in healthy and stenosed carotid artery models reconstructed from in vivo ultrasonography.

PURPOSE: This study investigated the accuracy of models reconstructed from ultrasound image processing by comparing the radial displacement waveforms of a subject-specific artery model and evaluated stress changes in the proximal shoulder, throat, and distal shoulder of the plaques depending on the degree of carotid artery stenosis. METHODS: Three groups of subjects (healthy and with less than 50% or more carotid stenosis) were evaluated with ultrasonography. Two-dimensional transverse imaging of the common carotid artery was performed to reconstruct the geometry. A longitudinal view of the same region was recorded to extract the Kelvin viscoelastic model parameters. The pulse pressure waveform and the effective pressure of perivascular tissue were loaded onto the internal and external walls of the model. Effective, circumferential, and principal stresses applied to the plaque throat, proximal shoulder, and distal shoulder in the transverse planes were extracted. RESULTS: The radial displacement waveforms of the model were closely correlated with those of image processing in all three groups. The mean of the effective, circumferential, and principal stresses of the healthy arteries were 15.01±4.93, 12.97±5.07, and 12.39±2.86 kPa, respectively. As stenosis increased from mild to significant, the mean values of the effective, circumferential, and first principal stresses increased significantly (97%, 74%, and 103% at the plaque throat, respectively) (P<0.05). The minimum effective stress was at the lipid pool. The effective stress in calcified areas was higher than in other parts of the artery wall. CONCLUSION: This model can discriminate differences in stresses applied to mildly and severely stenotic plaques.

Multimodality treatment in unresectable cholangiocarcinoma.

PURPOSE: Cholangiocarcinomas (CCs) are rare and highly malignant cancers. Although there are different treatment protocols for treatment of cholangiocarcinoma, we aimed to investigate a survival rate of patients with unresectable extrahepatic CCs (ECCs) receiving multimodality therapeutic protocol (MTP) (biliary drainage + external beam radiotherapy [EBRT] + brachytherapy and systemic chemotherapy). Similarly, we aimed to identify a relationship between survival time and associated factors in treatment outcome. MATERIAL AND METHODS: This retrospective study was performed on patients with ECC, who were referred to our university hospital between 2012 and 2015, and their imaging were diagnosed as unresectable. Patients underwent MTP including internal-external drainage catheter (F10-12) with insertion under fluoroscopy guidance, EBRT with 25-28 fractions and concurrent chemotherapy using capecitabine (Xeloda) 825 mg/m2 at the days of radiotherapy, followed by brachytherapy (BT) with iridium-192 (192Ir) or cobalt-60 (60Co) sources for 21 Gy in 3 consecutive days. Demographic variables, complications, laboratory tests, imaging findings, and survival time (OS - overall survival after diagnosis; CS - survival after catheter placement) were recorded. RESULTS: A total of 38 patients, with mean SD age = 58.08 (9.80) years, male = 22 (57.9%), were evaluated. According to Bismuth-Corlette classification, 15 (39.5%) were in stage IIIA, 5 (13.2%) were in stage IIIB, 10 (26.3%) were in stage IV, and 8 (21.2%) were undefined. Of those, 21 (55.3%), 15 (39.5%), and 17 (44.7%) were involved with liver parenchyma, great vessels, and regional lymph nodes, respectively. Mean SD of OS was 15.11 (8.10) months (median = 15; 95% CI: 13.25-16.69), and CS was 2-29 months (mean SD = 11.71 (7.29); median = 10; 95% CI: 10.05-13.37). Further analysis revealed a considerable decrease in OS and CS in those with an involvement of liver parenchyma, great vessels, regional lymph nodes, and Bismuth type IV. CONCLUSIONS: Multimodality therapeutic approach in patients with inoperable ECCs could definitely improve their survival time and decrease complications. Survival time is significantly depending on tumor staging, gender, and involvement of liver parenchyma, great vessels, and regional lymph nodes.

Estimation of Biomechanical Properties of Normal and Atherosclerotic Common Carotid Arteries.

PURPOSE: We developed a modified Kelvin model so that the periodic changes of the arterial intima-media thickness (IMT) over the cardiac cycle were involved. Modified model was implemented for carotid artery, solved via a parameter optimization technique and biomechanical parameters of the model. METHODS: Consecutive ultrasonic images of the common carotid artery of 30 male patients including 10 healthy subjects, 10 subjects with mild and 10 subjects with sever stenosis were recorded and processed offline. Temporal changes of the internal diameter and IMT were extracted using a combined maximum gradient and dynamic programming algorithm. The blood pressure waveforms were deduced calibrating the internal diameter waveforms using an empirical exponential relationship. RESULTS: According to the results of the ANOVA statistical analysis, mean values of the zero pressure radiuses, stress relaxation times, elastic moduli and strain relaxation times of the common carotid arteries of three groups were significantly different. Mentioned parameters increased 11, 24, 7 and 6% in patients with mild (< 50%) stenosis and 12, 73, 8 and 61% in the group with sever stenosis (> 50%) relative to healthy group. CONCLUSION: Present study can be an indicative of the general state of the vascular system and be used for discriminating atherosclerotic from healthy arteries.

Dose-dependent 60Co γ-radiation Effects on Human Endothelial Cell Mechanical Properties.

Exposure to ionizing radiation is unavoidable for noncancerous cells during the external radiotherapy process. Increasing the dose delivery fraction times leads to increasing the endothelial cell damage. Vascular abnormalities are commonly associated with the alternation of endothelium biomechanical properties. The goal of the present study was to quantify the elastic and viscoelastic properties of human umbilical vein endothelial cells (HUVECs) using the micropipette aspiration technique in conjunction with a theoretical model while an 8 Gy dose was given in four fractions. Confocal imaging was performed for evaluation of cytoskeletal changes during fractionation 60Co radiotherapy. The results indicated an increase in elastic modulus from 29.87 ± 1.04 Pa to 46.69 ± 1.17 Pa while the fractional doses increased from 0 Gy to 8 Gy along with the obvious cytoskeletal changes. Moreover, in the creep behavior of radiated groups, a significant decrease was shown in the time constant and viscoelastic properties. On the other hand, it was observed that the change in the biomechanical properties of the cells while applying a single fraction of 8 Gy was not exactly the same as that in the properties of the radiation-exposed cells while delivering an 8 Gy dose at 2 Gy per fraction. The observed differences in the biomechanical behavior of endothelium provide a quantitative description of radiobiological effects for evaluating the dose-response relationship as a biological dosimetry procedure.

Hemodynamic analysis of radiation-induced damage in common carotid arteries by using color Doppler ultrasonography.

PURPOSE: The aim of this study was to assess vascular changes and blood flow abnormalities in the common carotid arteries of patients with head and neck cancers after external radiotherapy, using color Doppler ultrasonography. METHODS: We studied 24 patients treated with external radiotherapy for various head and neck cancers. In order to study the acute effects of irradiation on common carotid blood flow and arterial diameter changes, color Doppler ultrasonography parameters such as peak systolic velocity, end diastolic velocity, mean velocity, systolic-to-diastolic velocity (S/D) ratio, pulsatility index (PI), resistive index (RI), and instantaneous diameter changes were evaluated before and after external radiotherapy. Additionally, the blood volume flow (VF) values in the peak systolic and end diastolic phases, as well as mean velocity, were evaluated throughout three cardiac cycles using B-mode ultrasonic image processing. RESULTS: The findings showed significant changes in the S/D ratio, PI, and RI of the common carotid arteries before and after external radiotherapy (P<0.05). Moreover, a significant decrease in artery diameter and blood VF was observed after radiotherapy relative to the pretreatment values. A significant correlation was found between the blood VF values estimated using ultrasonic measurements and mathematical methods throughout three cardiac cycles. CONCLUSION: The hemodynamic parameters of the common carotid arteries changed during radiotherapy. These arterial changes may lead to late adverse effects of radiotherapy, such as ischemic strokes and ischemic attacks.

Assessing the blood pressure waveform of the carotid artery using an ultrasound image processing method.

PURPOSE: The aim of this study was to introduce and implement a noninvasive method to derive the carotid artery pressure waveform directly by processing diagnostic sonograms of the carotid artery. METHODS: Ultrasound image sequences of 20 healthy male subjects (age, 36±9 years) were recorded during three cardiac cycles. The internal diameter and blood velocity waveforms were extracted from consecutive sonograms over the cardiac cycles by using custom analysis programs written in MATLAB. Finally, the application of a mathematical equation resulted in time changes of the arterial pressure. The resulting pressures were calibrated using the mean and the diastolic pressure of the radial artery. RESULTS: A good correlation was found between the mean carotid blood pressure obtained from the ultrasound image processing and the mean radial blood pressure obtained using a standard digital sphygmomanometer (R=0.91). The mean absolute difference between the carotid calibrated pulse pressures and those measured clinically was -1.333±6.548 mm Hg. CONCLUSION: The results of this study suggest that consecutive sonograms of the carotid artery can be used for estimating a blood pressure waveform. We believe that our results promote a noninvasive technique for clinical applications that overcomes the reproducibility problems of common carotid artery tonometry with technical and anatomical causes.

Coil Embolotherapy of Unilateral Diffuse Pulmonary Arteriovenous Malformations in a Nineteen-Year-Old Woman.

Pulmonary arteriovenous malformations (AVMs) are rare vascular malformations of the lung that usually led to a notable risk of serious and life-threatening complications. There is considerable debate about the best management of strategies for the group of patients with diffuse AVMs. Several therapeutic options have been reported for management of this abnormality among which coil embolization is currently the preferred ones. This report describes our experience with the use of coiling method for treatment of multiple AVMs in an adult patient.

Patient outcomes in a liver transplant program in Iran.

OBJECTIVES: The first liver transplant program in Tehran was started at Tehran University of Medical Sciences in 2002. The purpose of this study was to evaluate patient outcomes in this program. MATERIALS AND METHODS: From January 2002 to February 2013, there were 172 deceased-donor orthotopic liver transplants performed in 166 patients, including revision transplant in 6 patients. Outcomes were evaluated for 4 phases of the program: (1) phase 1 (2002 to 2005; 9 transplants); (2) phase 2 (2006 to 2009; 41 transplants); (3) phase 3 (2010 to 2011; 49 transplants); and (4) phase 4 (2012 to 2013; 73 transplants). RESULTS: The most frequent indications for liver transplant included cryptogenic cirrhosis, autoimmune hepatitis, and hepatitis B and C cirrhosis. During the progression from phase 1 to 4, there were significant decreases in median cold ischemia time, operative time, and transfusions (platelets, packed red blood cells, and fresh frozen plasma). The most frequent complications included infection and acute rejection. The overall median follow-up for all patients was 26 months (range, 9-144 mo). Frequency of 1-month, 3-month, 1-year, and 2-year survival increased from phase 1 to 4. Kaplan-Meier plots showed significant improvement in patient survival from phase 1 to 4 (P ≤ .001). The most common causes of death were sepsis and bleeding. CONCLUSIONS: Clinical outcomes with deceased-donor liver transplant may be improved with a cooperative multidisciplinary team, coordinated care from different specialties, increased experience, and modifications of anesthetic and surgical techniques. Comprehensive unified written protocols for preoperative, perioperative, and postoperative treatment may help improve outcomes after sufficient experience is achieved.

Establishing a liver transplantation program at Tehran University of Medical Sciences, Iran: a report of ten years of experience.

In 2001, a Liver Transplantation (LT) program was commenced in Imam Khomeini Hospital Complex as the first one in the capital city of Tehran which is the second liver transplantation center in Iran. This study presents the results of our 10-year experience with LT.

Carotid artery stenosis in patients with chronic kidney disease undergoing dialysis: epidemiological aspects, main risk factors and appropriate diagnostic criteria.

Knowledge of the epidemiology and risk profile of peripheral vascular disease among patients with chronic kidney disease (CKD) has a potential role for determining its outcome. This study assessed the epidemiological aspects and risk factors of carotid artery stenosis (CAS), assessed by clinical ankle brachial index (ABI), in patients on dialysis. This study was performed on 84 patients with CKD undergoing hemodialysis (HD; n = 65) or peritoneal dialysis (PD; n = 19). The ABI was measured using a concurrent oscillometric method and Color Doppler sonography. An ABI value >0.9 was defined as normal. Severity of the stenosis was determined using B-Mode sonography. Overall, CAS was seen in 51.2% of the study patients. No significant difference was found in the overall prevalence of CAS between the HD and PD groups (50.8% vs. 52.6%, P = 0.552). The mean ABI in the HD and PD groups was 1.13 and 1.06, respectively. Among patient characteristics, advanced age was found to be a predictor of CAS in the study patients. Gender, type of dialysis or underlying risk factors could not predict CAS. ABI measurement was an acceptable predictor of CAS, with a receiver operator characteristic of 0.645. The optimal cut-off for ABI for predicting CAS was identified at 1.0; this yielded a sensitivity of 70.8% and a specificity of 63.6% for the test. In conclusion, a notable number of patients undergoing dialysis for CKD had CAS. The main predictive factor was advanced age. ABI measurement seems to be an acceptable tool to diagnose CAS.

Measurement of colonic transit time based on radio opaque markers in patients with chronic idiopathic constipation; a cross-sectional study.

BACKGROUND: Constipation is one of the most common gastrointestinal disorders particularly in industrialized countries. Incidence of constipation varies from 3.4 % to 27.2% in different societies. Increase in urban population, industrialization of communities, changes in behavioral and nutritional habits and inactivity have increased the number of patients suffering from constipation. OBJECTIVES: The aim of the study was to measure colonic transit time in patients with chronic idiopathic constipation. PATIENTS AND METHODS: Fifty-two patients with chronic idiopathic constipation (according to ROME III criteria) were selected. Patients with diabetes mellitus, hypothyroidism, and hypoparathyroidism were excluded. Each patient took a capsule containing ten 1-3 mm long angiographic guide daily for 6 days. Abdominal x-ray was performed on the seventh day. Remaining markers in each segment were counted and segmental and total colonic transit time was calculated. The analysis was performed by SPSS version 18. In all tests, a P-value less than 0.05 was considered statistically significant. RESULTS: The mean age of patients was 36.9 ± 10.1 years. 80.8 % of patients were female. The mean total colonic transit time was 40.8 ±35.1 hours. 34.6 % of patients and 36.5 % of them had prolonged total and segmental colonic transit time. CONCLUSIONS: We found that prolonged total and segmental colonic transit time is common in patients with chronic idiopathic constipation.

Diagnostic accuracy of early computed tomographic angiography for visualizing medium sized inferior and posterior projecting carotid system aneurysms.

BACKGROUND: Conventional angiography, generally referred to as intra-arterial digital subtraction angiography, still remains the gold standard reference method for the diagnosis of intracranial aneurysms, helical computed tomography angiography (CTA) is a new non-invasive volumetric imaging method. OBJECTIVES: This study was conducted to screen patients presenting with subarachnoidhemorrhage by CTA before conventional digital subtraction angiography (DSA) and subsequently comparing the results for various aneurysm projections. PATIENTS AND METHODS: In a prospective study, 99 consecutive patients with an initial diagnosis of subarachnoid hemorrhage were screened for aneurysms with CTA followed by conventional DSA. There were 17 cases with negative angiograms in whom repeat angiograms, three months later were negative for 15 cases, while two cases were found to bear aneurysm on the repeat examination. Eighty two patients had at least one proven aneurysm on initial DSA and two on the repeat angiogram. Out of 84 patients, five underwent endovascular treatment and 79 patients who underwent surgical clipping were considered for projection evaluation. RESULTS: Sensitivity of CTA was 98.78% (95% confidence interval [CI], 93.4-99.7%), while the specificity was 100% (95% CI, 81.57-100%) and the kappa coefficient of agreement between CTA and DSA was 96.5%. The most significant discrepancies with DSA findings were for visualizing the projection of inferior and posterior projecting proximal anterior circulation aneurysms. CONCLUSIONS: Helical CTA was in good concordance with DSA for screening of cerebral aneurysms; however, for exact visualization of the aneurysm neck and its projection, especially if it is inferior or posterior, DSA remains the gold standard.

Evaluation of brain and cervical MRI abnormality rates in patients with systemic lupus erythematosus with or without neurological manifestations.

BACKGROUND: Central nervous system (CNS) involvement has been observed in 14-80% of patients with systemic lupus erythematosus (SLE). Magnetic resonance imaging (MRI) is an appropriate method for evaluating CNS involvement in these patients. Clinical manifestations and MRI findings of CNS lupus should be differentiated from other mimicking diseases such as multiple sclerosis (MS). OBJECTIVES: The aim of this study was to evaluate the prevalence and extent of brain and cervical cord MRI lesions of lupus patients. The relationship between neurological signs and symptoms and MRI findings were evaluated as well. PATIENTS AND METHODS: Fifty SLE patients who had been referred to the rheumatology clinic of our hospital within 2009 were included in a cross sectional study. All patients fulfilled the revised 1981 American College of Rheumatology (ACR) criteria for SLE. We evaluated the neurological signs and symptoms and brain and cervical MRI findings in these patients. RESULTS: Forty-one patients (82%) were female and nine (18%) were male. The mean age was 30.1 ± 9.3 years. Twenty eight (56%) patients had an abnormal brain MRI. No one showed any abnormality in the cervical MRI. The lesions in 20 patients were similar to demyelinative plaques. Seventeen patients with abnormal brain MRI were neurologically asymptomatic. There was only a significant relationship between neurological motor manifestations and brain MRI abnormal findings. CONCLUSIONS: Unlike the brain, cervical MRI abnormality and especially asymptomatic cord involvement in MRI is quite rare in SLE patients. This finding may be helpful to differentiate SLE from other CNS disorders such as MS.