Incidental deep venous thrombosis diagnosed on lower extremity computed tomography is a rare but clinically impactful finding.

BACKGROUND: In the setting of a known thrombotic event, computed tomography (CT) studies provide reasonable sensitivity for the diagnosis of deep venous thrombosis (DVT). However, the incidence and accuracy of a DVT diagnosis on CT studies not targeted for the detection of DVT are not well described. In addition, the clinical impact of DVTs incidentally identified on CT is unknown. METHODS: In this single-institution retrospective study, we queried all contrasted CT studies of the lower extremities performed over a 10-year period. Regular expressions applied to the radiology reports associated with the CT studies identified studies with positive findings associated with DVT. These selected reports were then manually reviewed to confirm the presence of a DVT. Patient demographics and relevant medical and surgical history were obtained through a chart review. Follow-up information was obtained for 1 year after the incident CT and included treatment course, additional imaging, and adverse events. An incidental DVT was one identified in a patient in whom the DVT was not noted in a prior study and for whom the study indication did not include concern for DVT or pulmonary embolism. RESULTS: Of 16,637 lower extremity contrasted CT studies queried, 37 study reports identified a DVT. However, only 13 patients had a finding of an incidental DVT (10-year incidence of 0.08%). Among these 13 patients, 11 underwent additional imaging, including 9 who had a subsequent venous duplex and 2 who had subsequent CT studies. Among those with a subsequent duplex, DVT was not identified in eight cases, whereas in one case, DVT was confirmed. Among those with subsequent CT studies, DVT was not identified in one case and was confirmed in one case. Of the 13 patients with incidental DVTs, 3 were initiated on anticoagulation based on their initial CT findings alone. Among these, two did not experience any complications from their DVT or anticoagulation regimen. One did experience major bleeding complications, requiring additional procedures. CONCLUSIONS: Incidental DVTs are a rare finding in lower extremity CT studies, noted to occur in only 0.08% of studies. Most patients with incidental DVTs receive additional imaging, with negative findings in 80% of cases. This study identified that 23% of patients were initiated on anticoagulation due to the CT findings, with a 33% rate of significant complications. Currently, a CT venogram is not recommended as a first-line modality for the diagnosis of DVT. However, there is no guidance regarding the need for repeat imaging in patients with incidentally diagnosed lower extremity DVTs identified on CT. Additional study is needed to provide evidence for guideline development.

Ultrasound Examination Without Axial Imaging is Sufficient for Preoperative Planning in Transcarotid Artery Revascularization (TCAR).

BACKGROUND: Duplex ultrasound is frequently used to determine the degree of carotid stenosis. However, axial imaging is typically obtained for operative planning for transcarotid artery revascularization (TCAR). We examined if ultrasound alone is sufficient before TCAR. METHODS: Data from the Vascular Quality Initiative TCAR Surveillance Project registry between 2016 and 2021 was obtained. Patients were divided into 2 groups-those with preoperative ultrasound-alone (US) and those with additional axial imaging (AX). Perioperative outcomes were compared utilizing univariate Chi-square, independent t-test, multivariate logistic regression, and Kaplan-Meier analysis. RESULTS: There were 3,418 patients identified: 682 in the US group and 2,736 in the AX group. More preoperative hypertension was reported in US (16.1% vs. 10.2%, P < 0.001) while cardiovascular disease (23% vs. 28.9%, P = 0.006) and prior ipsilateral stroke (22% vs. 32.7%, P = 0.002) were more prevalent in AX. More patients had history of contralateral carotid endarterectomy (13.6% vs. 16.7%, P = 0.035) or either ipsilateral (2.6% vs. 1.2%, P = 0.002) or contralateral (7.9% vs. 4.9%, P = 0.008) carotid artery stenting in the US group. Lower preoperative creatinine was reported in the US cohort (1.09 ± 0.01 vs. 1.18 ± 0.02, P < 0.001) while more were symptomatic in AX (28.2% vs. 36.2%, P < 0.001). There were no significant differences between lesion characteristics or operative decision making. A slightly higher total procedure time was seen in AX (73.7 ± 0.6 vs. 68.6 ± 1.3 min, P = 0.017). No differences were seen in perioperative transient ischemic attack/stroke or other immediate complications. At 2-year follow-up, both groups reported no significant differences in stroke-free survival (P = 0.750) and independent functional status remained near-identical (97.3% vs. 97.4%, P = 0.921). Kaplan-Meier analysis yielded no significant difference between mortality at 2 years (P = 0.563). Bivariate logistic regression modeling did reveal a statistically significant increase in likelihood of long-term ipsilateral stroke (odds ratio 1.77, P = 0.015) and non stroke-related complication in the postoperative period (odds ratio 4.81, P = 0.005). However, only a statistically significant relationship persisted in non-stroke complication when the model was controlled for between-group differences. CONCLUSIONS: No significant differences in postoperative or long-term complications were noted with additional AX in preoperative TCAR planning. Thus, duplex ultrasound offers a safe and effective alternative for those with contraindication or axial imaging.

The role of extracranial carotid duplex in predicting functional outcome in first time lacunae strokes.

BACKGROUND: Stroke is the third largest cause of death both worldwide and in Taiwan. Among the various stroke subtypes, lacunae strokes account for 20 to 30% of the total stroke population. Through vigorous risk control factors, the effective prevention and the long-term functional outcome remains are yet to be investigated. Carotid duplex is a non-invasive neuroimaging modality that is routinely applied to stroke patients. In the current research, we correlate baseline carotid duplex examination parameters with functional outcome assessment in an attempt to ascertain important variables for early outcome prediction. METHOD: We retrospectively recruited lacunae ischemic stroke patients from the Department of Neurology, Changhua Christian Hospital. Patient baseline demographics, biochemistry, neuroimaging, and outcome assessments were thoroughly evaluated via a modified Rankin Scale (mRS), NIHSS, and Barthel index scores, both prior and subsequent to patient discharge for a period of up to one year. Patients were divided into two groups based on their functional recovery status. This current study utilizes the Kaplan-Meier method to draw the survival curve and adopts the Cox proportional hazards model to estimate the hazard ratio between the two groups. The risk modeling method is also applied to formulate the best fit in seeking and identifying the variables, which has the most impact on determining theoutcome predictor. All statistical analyses were performed using R for Windows (version 3.6.3), with p < 0.05 meaning statistical significance and 0.05 < p < 0.1 denoting marginal statistical significance. RESULTS: One hundred forty-one ischemic lacunae stroke patients are included in the study, of which the follow-ups of 69 patients showed no physical functionality improvement, whereas 72 patients demonstrated favorable functional outcomes. In terms of underlying diseases, more than 80% of the patients suffered from hyperlipidemia upon hospitalization and more than 40% of the patients suffered from diabetes mellitus and heart disease. There was a significant difference in pulmonary disease between improvement and non-improvement in disability (1.4% vs 10.1%, p = 0.034). The average age of the improved group was lower than that of the non-improved group (65.5 vs. 72, p = 0.014), and the WBC was higher (8 vs 6.95, p = 0.005); furthermore, higher NIHSS scores (6.5 vs 3, p = 0.001) and lower Barthel index scores (47.5 vs 80, p < 0.001) were also noted. The group with improved mRS required a longer hospital stay (with a median of 10 days), while their un-improved counterpart required 8 days (p < 0.05). The majority of patients were discharged within 30 days, and there was a slight difference between the two survival curves (marginal statistical significance, 0.05 < p < 0.1). The hazard ratio of the improved group was 0.7188. There was a difference in the end diastolic velocity (EDV) of common carotid artery (CCA) between the lesion and non-lesion sides of the patients (p < 0.05). Risk-stratifying models indicate that diabetes mellitus, peak systolic velocity (PSV) of the internal carotid artery (ICA) on the lesion side, the diameter of the ICA on the non-lesion side, and the pulsatility index (PI) of the ICA and external carotid artery (ECA) were selected as the most important factors affecting the end diastolic velocity (EDV) of the common carotid artery (CCA) in all four models. CONCLUSION: In the current study, the most suitable length of stay in hospital for lacunae stroke patients to fully recuperate is ten days. Additionally, CCA EDV might be the key determinant, with baseline diabetes mellitus acting in a medium role, capable of altering long-term outcome functionality and recovery.

Cardiovascular risk scores in asymptomatic carotid stenosis: A validation study with ultrasonographic parameters.

We evaluated the feasibility of the Framingham stroke risk score (FSRS) and atherosclerotic cardiovascular disease (ASCVD) risk scores for asymptomatic carotid stenosis (ACS). In addition, we developed novel risk prediction models for ischemic stroke and composite outcomes by combining ultrasonographic parameters and conventional cardiovascular risk scores. We retrospectively enrolled 612 patients with ACS greater than 50% over 7 years and evaluated them using transcranial Doppler and carotid duplex ultrasonography. In total, 150 patients were included in the analysis. During the mean 5-year follow-up, 6 ischemic strokes and 25 composite events were detected. Among all ultrasonographic parameters, only a higher peak-systolic velocity/end-diastolic velocity ratio was detected and significantly associated with an increased risk of relevant ischemic stroke (hazard ratio: 1.502, 95% confidence interval: 1.036-1.968). The C-statistics of the FSRS and ASCVD risk scores were 0.646 and 0.649, respectively, for relevant ischemic stroke, and 0.612 and 0.649, respectively, for composite outcomes. C-statistics of the FSRS and ASCVD risk scores combined with ultrasonographic parameters increased to 0.937 and 0.941, respectively, for ischemic stroke, and 0.856 and 0.886, respectively, for composite outcomes. The study suggests that inclusion of ultrasonographic parameters in conventional cardiovascular scores helps identify the risk of further vascular events in ACS patients.

Early Results of Duplex-Guided Transradial Artery Fistuloplasties.

BACKGROUND: Although arteriovenous fistulae (AVFs) are the preferred mode of hemodialysis access because of their high patency rates, they are associated with an appreciable rate of nonmaturation. Balloon-assisted maturation (BAM) has been described to treat this issue. BAM is defined as repeated sequential graduated dilatation of the outflow vein. This study aims to evaluate the short-term complications of using the radial artery as an access for BAM procedures and fisutloplasties. Transradial access was used preferentially with multiple lesions in the AVF that were difficult to access with a single venous puncture. METHODS: Data were collected over 3 years on 44 office-based duplex-guided transradial access BAM procedures in 27 patients of whom 19 were men. BAM with ultrasound guidance was performed in 324 cases using a venous puncture during this period. The indication for the procedures was a failure of AVF maturation, and 5 cases were with short segment thrombectomy. All procedures were performed with local anesthesia only. Access site puncture, vessel cannulation, wire placement, and balloon advancement and insufflation were duplex-guided. The radial artery was punctured with ultrasound guidance and a 4-5 French low-profile sheath was placed. After crossing the lesion(s), 5,000 units of heparin was given. The radial artery was used as the access vessel for all procedures except one, in which the brachial artery was used in addition. Vascular injuries were classified based on the postprocedural duplex assessment. All patients had follow-up duplex scans within a week. RESULTS: The average age was 79 years (±14 SD, range 39-99 years). The types of AVF were 35 radio-cephalic, 1 radio-basilic, 2 brachio-brachial, 2 brachio-cephalic, and 4 brachio-basilic. The number of sites of lesions was 17 on the venous outflow, 7 perianastomotic, and 6 in the radial artery. In the remaining 14 failing AVFs, we were not able to identify any lesion. The balloon size ranged from 3-6 mm (28 patients) and 7-12 mm (16 patients). The most common injury was outflow vein wall injury (25), the formation of wall hematoma of the outflow vein (11), localized extravasation or rupture at the balloon site (4), spasm of the AVF (3), the formation of a puncture-site hematoma (2), and intimal flap (3). Extravasation was controlled with duplex-guided compression. There were no radial artery thromboses, and all the AVFs were patent on completion duplex and follow-up duplex. CONCLUSIONS: These data suggest that the radial artery could be used as a safe access route for BAM procedures with relatively low rates of complication. This approach can be considered as an adjunct in the armamentarium for angioplasty of AVF.

Comparative analysis of technical success rates and procedural complication rates of bedside inferior vena cava filter placement by intraprocedural imaging modality.

OBJECTIVE: Transabdominal duplex ultrasound, intravascular ultrasound (IVUS), and fluoroscopy have been used to assist with inferior vena cava filter (IVCF) placement since the late 1990s. We sought to compare the technical success and procedural complications of bedside placement of IVCF by the three commonly used modalities, namely, duplex ultrasound, IVUS, and combined IVUS and fluoroscopy. METHODS: All published reports including prospective and retrospective cohort studies and case series with a minimum of 10 patients from inception to August 2017 were identified by an electronic search of PubMed and Embase. The studies were then pooled to create a sample of patient data for statistical analysis. Bonferroni correction was used for comparison of the three groups. Values of P < .017 (two tailed) were considered statistically significant for the pairwise comparisons. RESULTS: A total of 21 studies comprising 2166 patients were identified. No significant differences were found in technical success and complication rates between the duplex ultrasound and IVUS arm, the combined IVUS and IVUS with fluoroscopy arm, or the duplex ultrasound and the combined IVUS with fluoroscopy arm. However, there was a trend toward decreased complication rates in the duplex ultrasound arm compared with the other two arms. A trend toward increased technical success was also observed in the combined IVUS and fluoroscopy arm compared with the other two arms. CONCLUSIONS: There are no significant differences in the technical success and complication rates between the three commonly used modalities of bedside IVCF placement.

Ultrasound-guided Angioplasty of Arteriovenous Fistulas for Hemodialysis: Benefits and Limitations.

BACKGROUND: Ultrasound-guided percutaneous angioplasty of arteriovenous fistulas (AVFs) makes it possible to avoid contrast agents and X-rays, to optimize the puncture site and to locate some stenoses on the fistulography, but is it really useful? Our objective is to report the results of our experience. METHODS: Between November 2012 and November 2017, all the patients treated according to this method in our center were collected retrospectively. The surgical indications were an insufficient maturation of the AVF, an increase in the venous pressure, an inadequate outflow, difficulties in puncture, a prolonged bleeding time, a flow drop, or an aneurysmal evolution. RESULTS: During this period, 50 patients had 72 ultrasound-guided angioplasties, 64 on native AVFs (88.9%) and 8 on prosthetic AVFs (11.1%). The technical success rate was 100%. The average preoperative flow of AVFs was 506.8 ± 302.2 vs. 955.9 ± 371.4 mL/min after angioplasty. The mean duration of follow-up was 13.4 ± 12.9 months. The cumulative rates of primary, assisted primary, and secondary patency were 43.5%, 68.8%, 81.5% at 1 year and 31.7%, 63.9%, 76.8% at 2 years, respectively. CONCLUSIONS: AVF angioplasty under ultrasound guidance only is feasible, effective, and represents an interesting alternative. A controlled study comparing ultrasound guidance with angioplasties performed under conventional angiographic guidance as the reference technique would better clarify the value of this technique.

Duplex-guided versus Conventional Percutaneous Transluminal Angioplasty of Iliac TASC II A and B Lesion: A Randomized Controlled Trial.

BACKGROUND: Percutaneous transluminal angioplasty (PTA) requires the use of nephrotoxic contrast. Patients with chronic kidney disease are more prone to develop contrast-induced nephropathy after utilization of contrast. Doppler ultrasound (duplex)-guided PTA (DuPTA) is a novel technique and has recently proven to be a successful alternative to conventional PTA in the treatment of iliac stenotic disease, without the use of contrast. In this randomized controlled trial, we evaluated whether DuPTA is as effective as conventional PTA in the treatment of iliac arterial stenotic disease. METHODS: From June 2013 till January 2017, 142 patients with symptomatic peripheral arterial disease (PAD), with significant (>70%) iliac stenotic lesions (both isolated and patients with multilevel disease without treatment of other lesions), were randomized to receive either conventional PTA or DuPTA of the iliac lesion, regardless of renal function. All patients received an ankle-brachial index, arterial mapping with duplex, and magnetic resonance angiography in the pre-operative work-up. Primary end point was procedural success, defined as passing the guidewire through the stenotic lesion and performing a PTA, with or without stenting. Reduction in peak systolic velocity (PSV) of ≥50% after successful PTA was required in the DuPTA group. Angiographic reduction of more than 50% was required in the interventional group. Decrease in PSV was evaluated in both groups 4 weeks post-procedure. RESULTS: Passing of the guidewire through the stenotic lesion was achieved in 96.5% of the DuPTA group and 98.8% of the PTA group (P = 0.34). Although PSV decreased significantly in both groups 4 weeks post-operative, PSV reduction ≥50% was significantly higher in the DuPTA group, respectively 78% vs. 58% in the PTA group (P < 0.01). The utilization of stents was significantly greater in the DuPTA group (52% vs. 18%, P < 0.01). After correction of potential confounders, significant difference in ≥50% PSV reduction remained; technical success did not differ significantly. CONCLUSIONS: DuPTA is a feasible alternative to conventional PTA in the treatment of PAD on the iliac anatomic level. Duplex examination before removal of the guidewire is recommended to evaluate adequate decrease in PSV and identify potential recoil.

Quantifying saphenous reflux.

BACKGROUND: Quantification of reflux is desirable in advanced chronic venous disease as clinical features are based on its adverse impact on ambulatory venous pressure (AMVP). Prior clinical observation suggests that reflux in a saphenous vein > 5 mm is likely significant. On the basis of normal calf pump mechanics, we hypothesized that a reflux volume ≥ 30 mL was necessary to upset pump equilibrium. METHODS: Venous laboratory data in 119 limbs with isolated saphenous reflux were analyzed. Reflux volume was calculated by duplex ultrasound (area × velocity × duration). The relationship of reflux volume to saphenous size, calf pump function (air plethysmography, AMVP), flow resistance (Poiseuille equation), and clinical severity were examined. RESULTS: Saphenous size had a bimodal relationship to reflux volume. Reflux volume of ≥ 30 mL occurred mostly (97% of limbs) with saphenous size of ≥ 5.5 mm, but 51% of saphenous veins >5.5 mm had reflux volumes <30 mL. This is because saphenous veins invariably carried less than their maximum reflux potential indicated by their size (Poiseuille equation). Variable additional focal resistance across refluxive valve cusps and narrower re-entry perforators is not taken into account when only saphenous truncal size is used for resistance calculation. Furthermore, the association of AMVP with reflux was found not to be based on a set (≥ 30 mL) threshold but was variable, depending on existing calf pump mechanics, compensatory in some (12% of limbs) and aggravating reflux effects in others (26%). Calf pump abnormalities were found in 70% of refluxive limbs and in 44% (n = 16) of contralateral limbs without any reflux. Reflux volume was significantly higher overall in limbs with ulcer (C6), but the range overlapped with lesser clinical classes. Seven of 14 limbs with active ulcers had reflux volume >30 mL; six of seven limbs with active ulcers and reflux volume of <30 mL had calf pump abnormalities that would be poorly tolerant of reflux even at these smaller volumes. CONCLUSIONS: Saphenous size alone cannot be used as an indicator of significant reflux. More than two thirds of the limbs with isolated saphenous reflux have calf pump abnormalities, which also occurred without reflux in the opposite limb--a novel finding. This means that in addition to quantification of reflux volume, calf pump assessment such as with air plethysmography and AMVP is desirable in clinical classes 3 and higher for proper assessment.

Prophylactic phenylephrine for iatrogenic priapism: a pilot study with Peyronie's patients.

PURPOSE: Although penile duplex Doppler ultrasonography (PDDU) is a common and integral procedure in a Peyronie's disease workup, the intracavernosal injection of vasoactive agents can carry a serious risk of priapism. Risk factors include young age, good baseline erectile function, and no coronary artery disease. In addition, patients with Peyronie's disease undergoing PDDU in an outpatient setting are at increased risk given the inability to predict optimal dosing. The present study was conducted to provide support for a standard protocol of early administration of phenylephrine in patients with a sustained erection after diagnostic intracavernosal injection of vasoactive agents to prevent the deleterious effects of iatrogenic priapism. MATERIALS AND METHODS: This was a retrospective review of Peyronie's disease patients who received phenylephrine reversal after intracavernosal alprostadil (prostaglandin E1) administration to look at the priapism rate. Safety was determined on the basis of adverse events reported by subjects and efficacy was determined on the basis of the rate of priapism following intervention. RESULTS: Patients with Peyronie's disease only had better hemodynamic values on PDDU than did patients with Peyronie's disease and erectile dysfunction. All of the patients receiving prophylactic phenylephrine had complete detumescence of erections without adverse events, including no priapism cases. CONCLUSIONS: The reversal of erections with phenylephrine after intracavernosal injections of alprostadil to prevent iatrogenic priapism can be effective without increased adverse effects.

Comparison of endovenous laser ablation and high ligation and stripping for varicose vein treatment: a meta-analysis.

OBJECTIVES: To evaluate the efficiency and safety of endovenous laser ablation (EVLA) for primary lower extremity varicosities compared with high ligation and stripping (HLS). METHOD: Prospective non-randomized studies and randomized control trials on comparison of EVLA and HLS in treating varicose vein were included in this study. A meta-analysis on the data of suitable 13 clinical trials was performed using the Mantel-Haenszel method and the risk ratio was calculated. Thirteen studies including a total of 2245 limbs were eligible for inclusion. Among them, 1128 limbs were treated with endovenous laser ablation, whereas 1117 were treated with high ligation and stripping. Primary outcome measures were technical success rates and recurrence rates at different follow-up duration and complication rates. RESULTS: No significant difference in initial technical success rates, Procedural failures were more common following EVLA compared with conventional surgery at one- and two-year follow-up. However, the duplex-detected and clinical recurrence rate was similar between conventional surgery and EVLA after one and two years. No statistical significance was found in postoperative phlebitis and bruise in EVLA and HLS (17.9% versus 21.5%). However, fewer complications were observed in EVLA compared with HLS, including bleeding and haematoma (1.28% versus 4.83%), wound infection (0.33% versus 1.91%) and paraesthesia (6.73% versus 11.27%). CONCLUSIONS: EVLA for varicose veins is safe and effective compared with HLS in a two-year range. More randomized controlled studies follow-up results are needed to clarify long-term recurrence (5 years).

Prophylactic Phenylephrine for Iatrogenic Priapism: A Pilot Study With Peyronie's Patients

PURPOSE: Although penile duplex Doppler ultrasonography (PDDU) is a common and integral procedure in a Peyronie's disease workup, the intracavernosal injection of vasoactive agents can carry a serious risk of priapism. Risk factors include young age, good baseline erectile function, and no coronary artery disease. In addition, patients with Peyronie's disease undergoing PDDU in an outpatient setting are at increased risk given the inability to predict optimal dosing. The present study was conducted to provide support for a standard protocol of early administration of phenylephrine in patients with a sustained erection after diagnostic intracavernosal injection of vasoactive agents to prevent the deleterious effects of iatrogenic priapism. MATERIALS AND METHODS: This was a retrospective review of Peyronie's disease patients who received phenylephrine reversal after intracavernosal alprostadil (prostaglandin E1) administration to look at the priapism rate. Safety was determined on the basis of adverse events reported by subjects and efficacy was determined on the basis of the rate of priapism following intervention. RESULTS: Patients with Peyronie's disease only had better hemodynamic values on PDDU than did patients with Peyronie's disease and erectile dysfunction. All of the patients receiving prophylactic phenylephrine had complete detumescence of erections without adverse events, including no priapism cases. CONCLUSIONS: The reversal of erections with phenylephrine after intracavernosal injections of alprostadil to prevent iatrogenic priapism can be effective without increased adverse effects.

Pros and cons for intravascular ultrasound in stenting.

Intravascular ultrasound is an invaluable tool, necessary for treating patients with venous occlusive disease. The combination of adequate preoperative imaging using duplex ultrasound and axial imaging with computed tomography and/or magnetic resonance allows preoperative identification of extravascular anatomic issues, which may lead to venous obstructive symptoms. During performance of the venous intervention, reliance upon contrast venography alone will lead to frequently missed intravascular pathology which inevitably will lead to inadequate treatment and higher overall failure rates than necessary.

Thermal effects of diagnostic ultrasound in an anthropomorphic skull model.

PURPOSE: Exposure to diagnostic ultrasound (US) can significantly heat biological tissue although conventional routine examinations are regarded as safe. The risk of unwanted thermal effects increases with a high absorption coefficient and extended insonation time. Certain applications of transcranial diagnostic US (TC-US) require prolonged exposure. An anthropomorphic skull model (ASM) was developed to evaluate thermal effects induced by TC-US of different modalities. The objective was to determine whether prolonged continuous TC-US application results in potentially harmful temperature increases. MATERIALS AND METHODS: The ASM consists of a human skull with tissue mimicking material and exhibits acoustic and anatomical characteristics of the human skull and brain. Experiments are performed with a diagnostic US device testing four different US modalities: Duplex PW (pulsed wave) Doppler, PW Doppler, color flow Doppler and B-mode. Temperature changes are recorded during 180 minutes of insonation. RESULTS: All measurements revealed significant temperature increases during insonation independent of the US modality. The maximum temperature elevation of + 5.25° C (p < 0.001) was observed on the surface of the skull exposed to duplex PW Doppler. At the bone-brain border a maximum temperature increae of + 2.01 °C (p < 0.001) was noted. Temperature increases within the brain were < 1.23 °C (p = 0.001). The highest values were registered using the duplex PW Doppler modality. CONCLUSION: TC-US induces significant local heating effects in an ASM. An application duration that extends routine clinical periods causes potentially harmful heating especially in tissue close to bone. TC-US elevates the temperature in the brain mimicking tissue but is not capable of producing harmful temperature increases during routine examinations. However, the risk of thermal injury in brain tissue increases significantly after an exposure time of > 2 hours.

Case of the disappearing heat-induced thrombus causing pulmonary embolism during ultrasound evaluation.

We report a case of a 58-year-old male patient who underwent successful endovenous radiofrequency ablation of the left great saphenous vein for CEAP class 4a venous disease. On the third postoperative day, he had a duplex ultrasound scan for evaluation which showed successful occlusion of the great saphenous vein (GSV) with class 2 endovenous heat-induced thrombus (EHIT) that disappeared during the evaluation and caused a pulmonary embolism. To our knowledge, no case of pulmonary embolism has been reported to occur during postoperative follow-up duplex scanning. Relevant literature is reviewed and a possible mechanism for thrombus dislodgement is entertained.

Assessment of the effect of radio contrast media on resistive index of renal artery by color doppler sonography.

Renal ischemia and direct toxic effect of contrast media are the main confounding causes of contrast-induced nephropathy (CIN). The effect of different contrast mediums on the resistance of renal artery is quite unclear. The aim of the present study was to assess the resistive index (RI) changes of renal segmental artery in color Doppler duplex sonography after injection of two different contrast mediums: iodixanol and iohexol. The RI of the renal segmental artery of 62 randomly chosen patients, with a normal baseline renal function, was calculated using color-coded Doppler sonography before and five minutes after bolus injection of two different contrast mediums. Thirty-one patients were administered 50 mL of iodixanol (Visipaque) and 31 patients were administered 50 mL of iohexol (Omnipaque) during intravenous urogram procedures. The RI results were analyzed and compared in two groups using two-tailed t-test. The mean RI of renal segmental artery increased significantly after administration of contrast media (mean +/- SD 0.61 +/- 0.046 vs 0.58 +/- 0.042; p< 0.001). The mean change of RI was 0.0387 +/- .00552 (mean +/- SE) in the setting of iohexol injection and 0.0216 +/- .00423 (mean +/- SE) five minutes after administration of iodixanol (p= 0.017). Both non-ionic iso-osmolar dimeric iodixanol and low-osmolar iohexol increase the renal artery resistance, but the changes are more dramatic with iohexol, suggesting better tolerance with iodixanol.

Takayasu arteritis presenting as epileptic seizures: a case report and brief review of the literature.

Neurological manifestations may complicate Takayasu arteritis (TA) but seizures are rare. A 40-year-old man with TA presented with recurrent episodes of epileptic seizures. Episodes consisted of a brief period of unresponsiveness followed by sudden falling, tonic stiffening and limb jerking. A postictal period with drowsiness, urine incontinence and a temporal loss of memory was also present. A carotid and intracranial duplex ultrasound revealed a reverse flow within the left vertebral artery indicating the presence of subclavian stealing syndrome while extracranial MRA suggested some stenosis at the origin of the left common carotid artery. The EEG was consistent with epilepsy. Neurological manifestations are secondary to ischemia caused by decreased blood flow in the involved carotid and vertebral arteries. Antiepileptic treatment proved effective and may be considered as a reasonable first approach. The stenotic lesions can be managed successfully with angioplasty but these procedures are associated with a high failure rate and may not be needed.

Preprocedural imaging: new options to reduce need for contrast angiography.

In vascular surgery, the gold standard for evaluation of the lower-extremity arterial tree has long been contrast arteriography (CA). Associated risks of CA are well-documented and include severe allergic reactions, arterial injury and/or hemorrhage, and contrast-induced nephropathy. Increasingly, less-invasive techniques, with fewer inherent risks for complication, are being explored as diagnostic alternatives. Magnetic resonance angiography, computed tomography angiography, and duplex arteriography, each offer distinct advantages, though are not without limitation. This review explores the indications, advantages, and disadvantages of these newer technologies and provides a comparison to CA as a means for defining the anatomic features of patients undergoing lower-extremity revascularization. This data suggests that noninvasive imaging technologies may, in the future, play an increasingly important role in the surgical evaluation of the patient with lower-extremity ischemia.

Randomized prospective study comparing routine versus selective use of sonography of the complete calf in patients with suspected deep venous thrombosis.

OBJECTIVE: We compared patient outcomes using two protocols: one routinely and the other selectively evaluating the calves completely during sonographic assessment of the lower extremities in patients with suspected deep venous thrombosis. SUBJECTS AND METHODS: In this randomized prospective study, patients were assigned to two groups. In one group, the deep calf veins were routinely evaluated in their entirety, and in the other group the calf was not evaluated unless the patient had symptoms or physical signs in the calf, in which case only the areas of symptoms or physical signs were evaluated. Patients were followed up for 3 months by medical record review, physician surveys, and telephone calls. An adverse outcome was a propagated deep venous thrombosis into the thigh or a pulmonary embolus. Examination times were recorded when possible. RESULTS: Of the 235 patients in the group in which the deep calf veins were routinely evaluated, we saw no adverse outcomes (0.0%; 97.5% one-sided confidence interval [CI], 0.6-1.6%). Of the 261 patients in the group in which the calf was only evaluated if there were signs or symptoms, we saw two adverse outcomes (0.8%; 95% CI, 0.1-2.7%). CONCLUSION: We found no significant difference in adverse outcomes in patients undergoing a protocol in which the deep calf veins were routinely evaluated or a protocol in which the calf was evaluated only if physical signs or symptoms were present.