Evaluation of Computerized Tomography Utilization in Comparison to Digital Subtraction Angiography in Patients with Peripheral Arterial Disease

BACKGROUND

Perform literature review to analyze current practices in imaging patient with peripheral arterial disease (PAD) and examine patterns in our practice in order to assess whether a lower extremity computed tomography angiography (CTA) in addition to digital subtraction angiography enhanced the assessment of vessel calcification, percentage of stenosis, and affected outcomes in patients with PAD.

METHODS

The study included patients who underwent lower extremity imaging and were followed up to 12 months. This population was divided into cases who had both an angiogram and CTA performed within 30 days (n = 20), and controls who underwent angiography only (n = 19). Baseline characteristics, imaging results, and clinical outcomes were analyzed.

RESULTS

Thirty-nine patients met study criteria (mean age was 58.4 years, 69.2% were males, and 33.3% had diabetes). Patients mostly presented with tissue loss/rest pain (10.3%), claudication (15.4%), acute limb (10.3%), and trauma (15.4%). We have not observed any statistically significant differences in various examined blood vessels when their features (e.g., vessel diameter, stenosis, calcifications) were assessed by CTA combined with angiography versus angiography alone. The exceptions were external iliac artery, superficial femoral artery and dorsalis pedis vessels. In external iliac artery percentage of stenosis was 1.11% as determined by computed tomography (CT) scan versus 30% by angiography (P = 0.009). For superficial femoral artery stenosis, the percentage determined by CT was 48.68% vs. 81.41% by angiography, and observed difference between 2 modalities was statistically significant (P = 0.025). For dorsalis pedis percentage of stenosis detected by CT scan was 60.63% vs. 22.73% by angiography, and the differences in findings by these modalities were statistically significant (P = 0.039). The most frequent perioperative complication was cardiac-related (35.5%). Nineteen patients were readmitted and 8 had reinterventions within 12 months.

CONCLUSIONS

Both imaging modalities yielded similar results for assessing vessel calcification and percentage of stenosis regardless of anatomic vessel location. Overall, utilization of CTA in addition to angiography for large vessels above the knee (e.g., iliac artery, superficial femoral artery) and below the knee for dorsalis pedis provided more detailed information on the properties of these vessels. Therefore, during preoperative assessments, CTA may be helpful in addition to angiography for planning surgical and endovascular interventions for symptomatic PAD treatment in larger vessels.

Preoperative Vascular Imaging in Lower Extremity Free Flap Reconstruction: Comparison Between Imaging Modalities

BACKGROUND

Adequate vascular anatomy and perfusion status are essential for successful lower extremity free tissue transfer. Computed tomography angiography (CTA) is widely available, minimally invasive, and enables visualization of soft tissues and bones. Angiography permits temporal evaluation of flow, identifies potential needs for concurrent endovascular interventions, and enhances visibility in the setting of hardware. Despite widespread availability of these imaging modalities, no standardized algorithm for preoperative imaging prior to lower extremity free flap reconstruction exists.

METHODS

Current Procedural Terminology (CPT) codes identified patients undergoing free flap reconstruction of the lower extremity over an 18-year period (2002-2020). Electronic medical records were reviewed for patient, treatment, and imaging characteristics, and pre- and post-imaging laboratory values. Outcomes included imaging findings and related complications and surgical outcomes.

RESULTS

In total, 405 patients were identified, with 59% (n = 238) undergoing preoperative imaging with angiography, 10% (n = 42) with CTA, 7.2% (n = 29) with both imaging modalities, and 24% (n = 96) with neither performed. Forty percent (122 of 309) of patients who underwent preoperative imaging had less than 3-vessel runoff. Four patients developed contrast-induced nephropathy (CIN) after angiography only and one after having both CTA and angiography. Vessel runoff on CTA and angiography demonstrated moderate correlation.

CONCLUSION

Most patients undergoing lower extremity free tissue transfer underwent preoperative imaging with angiography and/or CTA, 40% of which had less than 3-vessel runoff. Both angiography and CTA had low complication rates, with no statistically significant risk factors identified. Specifically, the incidence of CIN was not found to be significant using either modality. We discuss our institutional algorithm to aid in decision-making for preoperative imaging prior to lower extremity free flap reconstruction. Specifically, we recommend angiography for patients with peripheral vascular disease, internal hardware, or distal defects secondary to trauma.

Sex Differences in Mortality Risk after the First Hospitalisation with Lower Extremity Peripheral Arterial Disease

OBJECTIVE

Lower extremity peripheral arterial disease (PAD) is a severe condition that increases the risk of major adverse cardiovascular events, major adverse limb events, and all cause mortality. This study aimed to investigate the mortality risk among females and males hospitalised for the first time with lower extremity PAD.

METHODS

Three cohorts of patients who were admitted for the first time with lower extremity PAD in 2007 - 2010, 2011 - 2014, and 2015 - 2018 were constructed. For the 2007 - 2010 and 2011 - 2014 cohorts, the 28 day, one year, and five year mortality rates were calculated, assessing survival time from date of hospital admission until date of death, end of study period, or censoring. For the 2015 - 2018 cohort, only 28 day and one year mortality were investigated due to lack of follow up data. Mortality rates of these cohorts were compared with the general population using standardised mortality rates (SMRs), and the risk of death between sexes was evaluated using Cox proportional hazards models. Cox models were adjusted for age, cardiovascular disease, and diabetes mellitus to account for potential confounding factors.

RESULTS

In total, 7 950, 9 670, and 13 522 patients were included in the 2007 - 2010, 2011 - 2014, and 2015 - 2018 cohorts, respectively. Over 60% of individuals in each cohort were males. Mortality rates at 28 day and one year remained stable across all cohorts, while the five year mortality rate increased for both males and females in the 2011 - 2014 cohort. The SMRs both of females and males with PAD were significantly higher than in the general population. Multivariable regression analyses found no significant differences in mortality risk between sexes at 28 day and one year. However, the five year mortality risk was lower in females, with a hazard ratio of 0.89 (95% confidence interval [CI] 0.83 - 0.97) in the 2007 - 2010 cohort and 0.88 (95% CI 0.82 - 0.94) in the 2011 - 2014 cohort.

CONCLUSION

The five year mortality risk has increased, and females face a lower mortality risk than males. Lower extremity PAD still carries unfavourable long term consequences compared with the general population.

Contrast-free ultrasound imaging for blood flow assessment of the lower limb in patients with peripheral arterial disease: a feasibility study

While being a relatively prevalent condition particularly among aging patients, peripheral arterial disease (PAD) of lower extremities commonly goes undetected or misdiagnosed due to its symptoms being nonspecific. Additionally, progression of PAD in the absence of timely intervention can lead to dire consequences. Therefore, development of non-invasive and affordable diagnostic approaches can be highly beneficial in detection and treatment planning for PAD patients. In this study, we present a contrast-free ultrasound-based quantitative blood flow imaging technique for PAD diagnosis. The method involves monitoring the variations of blood flow in the calf muscle in response to thigh-pressure-cuff-induced occlusion. Four quantitative metrics are introduced for analysis of these variations. These metrics include post-occlusion to baseline flow intensity variation (PBFIV), total response region (TRR), Lag0 response region (L0RR), and Lag4 (and more) response region (L4 + RR). We examine the feasibility of this method through an in vivo study consisting of 14 PAD patients with abnormal ankle-brachial index (ABI) and 8 healthy volunteers. Ultrasound data acquired from 13 legs in the patient group and 13 legs in the healthy group are analyzed. Out of the four utilized metrics, three exhibited significantly different distributions between the two groups (p-value < 0.05). More specifically, p-values of 0.0015 for PBFIV, 0.0183 for TRR, and 0.0048 for L0RR were obtained. The results of this feasibility study indicate the diagnostic potential of the proposed method for the detection of PAD.

FINE-NEEDLE ANGIOGRAPHY IN CHRONIC LIMB-THREATENING ISCHEMIA DIABETIC PATIENTS

OBJECTIVE

The aim: The features and efficiency of performing fine-needle angiography for Chronic Limb-Threatening Ischemia (CLTI) in Diabetic Patients diagnosis.

PATIENTS AND METHODS

Materials and methods: From 2015-2020, a total of 180 angiography procedures were performed in below-the-knee (BTK) arterial disease diabetic patients with CLTI (Rutherford category 4 to 6). Relative contraindications such as severe heart failure, myocardial infarction (MI), arterial hypertension, impaired renal function, allergy to contrast media and intolerance to antiplatelet therapy we carefully evaluated and compared with the major amputation risks. Patients were selected with adequate inflow to the common and popliteal arterys, as defined by presence of normal ipsilateral femoral and popliteal pulse, biphasic or triphasic Doppler waveform. Ultrasound controlled fine-needle angiography, by retrograde puncture of the superficial femoral artery (SFA) was performed with an 18G-70mm angiographic needle in 96 patients (1st group). Antegrade angiography using femoral sheath in 84 patients (2nd group).

RESULTS

Results: We have obtained adequate visualization BTK vessels by administering "Omnipak 300" 70% solution 9 mL with a power injector at a 3 mL/sec rate through the needle. Through the sidearm of the femoral sheath a total of contrast 15 mL, administered at 5 mL/sec rate. Fine-needle angiography 2.16 times reduces the injected contrast amount in patients. The hemorrhagic events frequency in the 1st group was significantly lower.

CONCLUSION

Conclusions: Fine-needle angiography is recommended for CLTI Diabetic Patients diagnosis.

Lower extremity CT angiography in peripheral arterial disease: from the established approach to evolving technical developments

With the advent of multidetector computed tomography (CT), CT angiography (CTA) has gained widespread popularity for noninvasive imaging of the arterial vasculature. Peripheral extremity CTA can nowadays be performed rapidly with high spatial resolution and a decreased amount of both intravenous contrast and radiation exposure. In patients with peripheral artery disease (PAD), this technique can be used to delineate the bilateral lower extremity arterial tree and to determine the amount of atherosclerotic disease while differentiating between acute and chronic changes. This article provides an overview of several imaging techniques for PAD, specifically discusses the use of peripheral extremity CTA in patients with PAD, clinical indications, established technical considerations and novel technical developments, and the effect of postprocessing imaging techniques and structured reporting.

Predictors of subclinical cardiovascular affection in Egyptian patients with juvenile idiopathic arthritis subtypes

Background

To assess the subclinical cardiovascular affection in juvenile idiopathic arthritis (JIA) Egyptian patient subtypes using Doppler ultrasonography (US) for carotid and femoral arteries and detecting their predictors

Results

Forty percent of the patients were polyarticular type, while 40% were systemic onset and 20% were oligoarticular. There was a statistically significant difference between JIA and controls in all parameters of subclinical atherosclerosis by ultrasonography except right external carotid velocity and (right and left) femoral velocity. There was also a highly significant increase in intima-media thickness (IMT) in systemic onset type of JIA. There was a statistically positive correlation between increased internal carotid velocity (right and left) and high erythrocyte sedimentation rate (ESR), high-sensitivity C-reactive protein (hs-CRP), lipid profile, and disease activity. High disease activity and lipid profile were valid predictors of subclinical atherosclerotic cardiovascular affection in JIA.

Conclusion

Increased cardiovascular risks and subclinical atherosclerosis in patients with JIA especially systemic onset type may be due to higher prevalence of multiple risk factors in these patients. Doppler ultrasonography is a simple, non-invasive technique which can be used to detect subclinical atherosclerosis in JIA. Control of disease activity by treat to target strategy and proper diet control should be applied for every patient with JIA especially those with systemic onset type for future prevention of cardiovascular disease.

Ultrasound imaging of the arterial system

Ultrasound (US) and Doppler are often the first imaging to be carried out for arterial disease, and with good reason. US is noninvasive, free of radiation exposure and crucial for follow up imaging. The review that follows aims to highlight the various applications of US in imaging of the arterial system.

Peripheral artery disease: the new frontiers of imaging techniques to evaluate the evolution of regenerative medicine

Introduction: Stem cells (ESC, iPSC, MSC) are known to have intrinsic regenerative properties. In the last decades numerous findings have favored the development of innovative therapeutic protocols based on the use of stem cells (Regenerative Medicine/Cell Therapy) for the treatment of numerous diseases including PAD, with promising results in preclinical studies. So far, several clinical studies have shown a general improvement of the patient's clinical outcome, however they possess many critical issues caused by the non-randomized design of the limited number of patients examined, the type cells to be used, their dosage, the short duration of treatment and also their delivery strategy. Areas covered: In this context, the use of the most advanced molecular imaging techniques will allow the visualization of very important physio-pathological processes otherwise invisible with conventional techniques, such as angiogenesis, also providing important structural and functional data. Expert opinion: The new frontier of cell therapy applied to PAD, potentially able to stop or even the process that causes the disease, with particular emphasis on the clinical aspects that different types of cells involve and on the use of more innovative molecular imaging techniques now available.

ImmunoPET of CD146 in a Murine Hindlimb Ischemia Model

Peripheral arterial disease (PAD) consists of a persistent obstruction of lower-extremity arteries further from the aortic bifurcation attributable to atherosclerosis. PAD is correlated with an elevated risk of morbidity and mortality as well as of deterioration of the quality of life with claudication and chronic leg ischemia being the most frequent complications. Therapeutic angiogenesis is a promising therapeutic strategy that aims to restore the blood flow to the ischemic limb. In this context, assessing the efficacy of pro-angiogenic treatment using a reliable noninvasive imaging technique would greatly benefit the implementation of this therapeutic approach. Herein, we describe the angiogenesis and perfusion recovery characteristics of a mouse model of PAD via in vivo positron emission tomography (PET) imaging of CD146 expression. For that, ischemia was generated by ligation and excision of the right femoral artery of Balb/C mice and confirmed through laser Doppler imaging. The angiogenic process, induced by ischemia, was noninvasively monitored and quantified through PET imaging of CD146 expression in the injured leg using a ⁶⁴Cu-labeled anti-CD146 monoclonal antibody, ⁶⁴Cu-NOTA-YY146, at post-operative days 3, 10, and 17. The CD146-specific character of ⁶⁴Cu-NOTA-YY146 was verified via a blocking study performed in another cohort at day 10 after surgery. Tracer uptake was correlated with in situ CD146 expression by histological analysis. PET scan results indicated that ⁶⁴Cu-NOTA-YY146 uptake in the injured leg was significantly higher, with the highest uptake with a value of 14.1 ± 2.0 %ID/g at post-operative day 3, compared to the normal contralateral hindlimb, at all time points (maximum uptake of 2.2 ± 0.2 %ID/g). The pre-injection of a blocking dose resulted in a significantly lower tracer uptake in the ischemic hindlimb on day 10 after surgery, confirming tracer specificity. CD146/CD31 immunofluorescent co-staining showed an excellent correlation between the high uptake of the tracer with in situ CD146 expression levels and a marked co-localization of CD146 and CD31 signals. In conclusion, persistent and CD146-specific tracer accumulation in the ischemic hindlimb was observed, confirming the feasibility of ⁶⁴Cu-NOTA-YY146 to be used as an imaging agent to monitor the progression of angiogenesis and recovery in future PAD research.

Imaging techniques to evaluate cell therapy in peripheral artery disease: state of the art and clinical trials

Cell-based therapies, as potential approach to cure peripheral artery disease (PAD), have been clinically investigated after promising results in preclinical models. The so far published studies are very heterogeneous, as different cell sources, cell types, amounts of administered cells and delivering strategies have been used. Overall, cell therapies for PAD bring about a general improvement of patient's clinical condition, even though conclusions cannot be established due to the small size and non-randomized design of these trials. In this context, non-invasive imaging techniques, aimed to monitor angiogenesis and neovascularization after cell therapy, will help the follow-up of clinical studies. However, still much work is needed to establish advanced imaging procedure to overcome the limitation of the current techniques and to accumulate more data in large populations of patients. Here, we report the main imaging techniques employed to evaluate the outcome of the different cell-based therapies in PAD. Moreover, we focus on both published and ongoing clinical trials utilizing cell therapy in PAD.

An integrated teaching method of gross anatomy and computed tomography radiology

It is essential for medical students to learn and comprehend human anatomy in three dimensions (3D). With this in mind, a new system was designed in order to integrate anatomical dissections with diagnostic computed tomography (CT) radiology. Cadavers were scanned by CT scanners, and students then consulted the postmortem CT images during cadaver dissection to gain a better understanding of 3D human anatomy and diagnostic radiology. Students used handheld digital imaging and communications in medicine viewers at the bench-side (OsiriX on iPod touch or iPad), which enabled "pixel-to-tissue" direct comparisons of CT images and cadavers. Students had lectures and workshops on diagnostic radiology, and they completed study assignments where they discussed findings in the anatomy laboratory compared with CT radiology findings. This teaching method for gross and radiological anatomy was used beginning in 2009, and it yielded strongly positive student perspectives and significant improvements in radiology skills in later clinical courses.

Diabetes mellitus and peripheral vascular disease: diagnosis and management

Diabetes mellitus and peripheral artery disease are prevalent diseases throughout the world and often present simultaneously in the same patient, which has direct implications for their diagnosis and management. Refinements of existing and development of new diagnostic and treatment modalities are changing the management of these diseases. This article reviews the significant pathologic basis, history, and physical examination findings with respect to each disease and their presentation together. Advantages and disadvantages of different diagnostic modalities, including noninvasive studies and imaging technologies, are discussed. General medical management principles and indications, techniques, and efficacy of surgical and endovascular interventions are reviewed.

Mechanical thrombectomy using Rotarex system and stent-in-stent placement for treatment of distal femoral artery occlusion secondary to stent fracture - a case report and literature review

Background:

Treatment of peripheral arterial diseases may be distinguished into conservative and interventional management; the latter is divided into surgical and endovascular procedures. Management of peripheral artery stenosis and occlusion with vascular stents is associated with the risk of late complications such as restenosis, stent fracture or dislocation.

Case Report:

A 62-year-old woman with generalized atherosclerosis, particularly extensive in lower limb arteries, was admitted to the Department of Angiology 11 months after having an endovascular procedure performed due to critical ischemia of left lower limb. Because of stent occlusion, a decision to perform angiographic examination of lower limb arteries was made. Examination revealed occlusion of the superficial femoral artery along its entire length, including previously implanted stents. Distal stent was fractured with slight dislocation of the proximal segment. A decision was made to perform mechanical thrombectomy using a Rotarex system followed by a stent-in-stent placement procedure. Follow-up angiography and ultrasound scan performed 24 hours after the procedure revealed a patent vessel with satisfactory blood flow.

Discussion:

Nowadays, imaging diagnostics of peripheral artery stenosis involves non-invasive examinations such as ultrasound, minimally invasive examinations such as angio-MRI and MDCT, or invasive examinations such as DSA and IVUS. DSA examinations are used to confirm significant stenosis or occlusion of a vessel, particularly when qualifying a patient for endovascular treatment. Due to their anatomic location, the superficial femoral artery and the popliteal artery are subject to various forces e.g. those exerted by the working muscles. Mechanical thrombectomy and atherectomy are efficient methods of arterial recanalization used in the treatment of acute, subacute or even chronic occlusions or stenosis of peripheral vessels.

Conclusions:

Frequency of angioplasty and vascular stent implantation procedures is increased in patients with peripheral arterial disease, thus increasing the incidence of reported early and late complications such as acute stent thrombosis, restenosis and stent fractures. The Rotarex transcutaneous mechanical thrombectomy system is an efficient method of treating occlusions in arterial stents. It is also safe when performed by experienced operators.

PET/SPECT imaging of hindlimb ischemia: focusing on angiogenesis and blood flow

Peripheral artery disease (PAD) is a result of the atherosclerotic narrowing of blood vessels to the extremities, and the subsequent tissue ischemia can lead to the up-regulation of angiogenic growth factors and formation of new vessels as a recovery mechanism. Such formation of new vessels can be evaluated with various non-invasive molecular imaging techniques, where serial images from the same subjects can be obtained to allow the documentation of disease progression and therapeutic response. The most commonly used animal model for preclinical studies of PAD is the murine hindlimb ischemia model, and a number of radiotracers have been investigated for positron emission tomography (PET) and single photon emission computed tomography (SPECT) imaging of PAD. In this review article, we summarize the PET/SPECT tracers that have been tested in the murine hindlimb ischemia model as well as those used clinically to assess the extremity blood flow.

A theoretical comparison of x-ray angiographic image quality using energy-dependent and conventional subtraction methods

PURPOSE

X-ray digital subtraction angiography (DSA) is widely used for vascular imaging. However, the need to subtract a mask image can result in motion artifacts and compromised image quality. The current interest in energy-resolving photon-counting (EPC) detectors offers the promise of eliminating motion artifacts and other advanced applications using a single exposure. The authors describe a method of assessing the iodine signal-to-noise ratio (SNR) that may be achieved with energy-resolved angiography (ERA) to enable a direct comparison with other approaches including DSA and dual-energy angiography for the same patient exposure.

METHODS

A linearized noise-propagation approach, combined with linear expressions of dual-energy and energy-resolved imaging, is used to describe the iodine SNR. The results were validated by a Monte Carlo calculation for all three approaches and compared visually for dual-energy and DSA imaging using a simple angiographic phantom with a CsI-based flat-panel detector.

RESULTS

The linearized SNR calculations show excellent agreement with Monte Carlo results. While dual-energy methods require an increased tube heat load of 2× to 4× compared to DSA, and photon-counting detectors are not yet ready for angiographic imaging, the available iodine SNR for both methods as tested is within 10% of that of conventional DSA for the same patient exposure over a wide range of patient thicknesses and iodine concentrations.

CONCLUSIONS

While the energy-based methods are not necessarily optimized and further improvements are likely, the linearized noise-propagation analysis provides the theoretical framework of a level playing field for optimization studies and comparison with conventional DSA. It is concluded that both dual-energy and photon-counting approaches have the potential to provide similar angiographic image quality to DSA.

Diagnostic approach to peripheral arterial disease

This article discusses diagnostic imaging techniques used in the evaluation and management of patients with peripheral arterial disease (PAD). Along with a complete vascular examination, noninvasive physiologic testing is used for the initial evaluation of patients with suspected PAD. Duplex ultrasonography provides information on the degree of stenosis or occlusion within a vessel and allows assessment of the vessel wall and plaque morphology. Angiographic imaging techniques should be reserved for determining the optimal endovascular or surgical approach for patients requiring revascularization. Together, all available diagnostic modalities contribute to successful evaluation and management of patients with PAD.