CT angiography of the upper extremity arterial system: Part 1-Anatomy, technique, and use in trauma patients. AJR Am J Roentgenol. 2013;201:745-752. [PMID: 24059363 DOI: 10.2214/ajr.13.11207]

Upper limb computed tomography (CT) angiography in the emergency department

A range of abnormalities may acutely affect the upper limb (UL) extremity vasculature including trauma, peripheral vascular disease, and inflammatory conditions. Significant technical advances in computed tomography angiography (CTA) have led to the widespread adoption of this noninvasive modality for rapid evaluation of UL arterial abnormalities in the emergency department setting. A key advantage of CTA over traditional digital subtraction angiography (DSA) is the ability to evaluate concurrent osseous and soft tissue injuries. Accurate identification of pathology requires knowledge of normal UL arterial anatomy in addition to a high-quality study, which may be achieved with a robust CTA protocol. We describe the spectrum of imaging findings on upper limb CTA associated with various acute presentations. Traumatic vascular injuries may occur secondary to penetrating and blunt aetiologies appearing on CTA as contrast extravasation, pooling, pseudoaneurysm, occlusion, and arteriovenous fistula. Peripheral vascular disease manifests as atherosclerotic plaques with thready downstream opacification, and these may precipitate acute thromboembolic events. Inflammatory conditions affecting the UL vasculature includes large and small vessel vasculitides characterised by arterial mural thickening. The use of modalities, including ultrasound and magnetic resonance angiography (MRA), should be considered for further characterisation where appropriate.

CTA Imaging of Peripheral Arterial Injuries

Traumatic vascular injuries consist of direct or indirect damage to arteries and/or veins and account for 3% of all traumatic injuries. Typical consequences are hemorrhage and ischemia. Vascular injuries of the extremities can occur isolated or in association with major trauma and other organ injuries. They account for 1-2% of patients admitted to emergency departments and for approximately 50% of all arterial injuries. Lower extremities are more frequently injured than upper ones in the adult population. The outcome of vascular injuries is strictly correlated to the environment and the time background. Treatment can be challenging, notably in polytrauma because of the dilemma of which injury should be prioritized, and treatment delay can cause disability or even death, especially for limb vascular injury. Our purposes are to discuss the role of computed tomography angiography (CTA) in the diagnosis of vascular trauma and its optimized protocol to achieve a definitive diagnosis and to assess the radiological signs of vascular injuries and the possible pitfalls.

Current Standards for and Clinical Impact of Emergency Radiology in Major Trauma

In industrialized countries, high energy trauma represents the leading cause of death and disability among people under 35 years of age. The two leading causes of mortality are neurological injuries and bleeding. Clinical evaluation is often unreliable in determining if, when and where injuries should be treated. Traditionally, surgery was the mainstay for assessment of injuries but advances in imaging techniques, particularly in computed tomography (CT), have contributed in progressively changing the classic clinical paradigm for major traumas, better defining the indications for surgery. Actually, the vast majority of traumas are now treated nonoperatively with a significant reduction in morbidity and mortality compared to the past. In this sense, another crucial point is the advent of interventional radiology (IR) in the treatment of vascular injuries after blunt trauma. IR enables the most effective nonoperative treatment of all vascular injuries. Indications for IR depend on the CT evidence of vascular injuries and, therefore, a robust CT protocol and the radiologist's expertise are crucial. Emergency and IR radiologists form an integral part of the trauma team and are crucial for tailored management of traumatic injuries.

Life and Limb: Current Concepts in Endovascular Treatment of Extremity Trauma

Traumatic injury is the leading cause of death worldwide in younger patient populations and extremity trauma with associated vascular injury accounts for many trauma-related deaths. Iatrogenic injury is also a common cause of extremity vascular trauma and the incidence of iatrogenic injury will likely increase as endovascular techniques continue to become more ubiquitous. For many vascular injuries involving the extremities, surgical repair is viewed as the standard of care. Historically, endovascular techniques did not play a role in the treatment of these vascular injuries, rather they were utilized only as part of the diagnostic assessment; however, there is an increasing trend toward endovascular management of extremity vascular trauma. No validated, widely implemented algorithm to select patients for endovascular intervention exists. Transcatheter techniques, however, play an important role in the management of these patients. For arterial injuries, embolization can be used to rapidly achieve hemostasis if the vessel can be sacrificed. More advanced endovascular techniques such as stent-graft placement may be best employed in the context of isolated, proximal extremity injuries, although there is increasing literature supporting the use of advanced techniques for more distal arterial injuries. The management of peripheral venous trauma remains controversial; however, there is growing data describing successful endovascular management of some peripheral venous injuries. The purpose of this article is to review extremity vascular trauma, concepts of injury triage, endovascular techniques, and intraprocedural considerations.

CT angiography and MRI of hand vascular lesions: technical considerations and spectrum of imaging findings

Vascular lesions of the hand are common and are distinct from vascular lesions elsewhere because of the terminal vascular network in this region, the frequent hand exposure to trauma and microtrauma, and the superficial location of the lesions. Vascular lesions in the hand may be secondary to local pathology, a proximal source of emboli, or systemic diseases with vascular compromise. In most cases, ischaemic conditions are investigated with Doppler ultrasonography. However, computed tomography angiography (CTA) or dynamic contrast-enhanced magnetic resonance angiography (MRA) is often necessary for treatment planning. MR imaging is frequently performed with MRA to distinguish between vascular malformations, vascular tumours, and perivascular tumours. Some vascular tumours preferentially affect the hand, such as pyogenic granulomas or spindle cell haemangiomas associated with Maffucci syndrome. Glomus tumours are the most frequent perivascular tumours of the hand. The purpose of this article is to describe the state-of-the-art acquisition protocols and illustrate the different patterns of vascular lesions and perivascular tumours of the hand.

Imaging primer for CT angiography in peripheral vascular trauma

The use of computed tomography angiography (CTA) for the evaluation of peripheral vascular trauma has become increasingly prevalent in the past decade with the development of multidetector CT (MDCT) and multiple studies subsequently demonstrating high sensitivity, specificity, and diagnostic accuracy when compared with conventional angiography. Additional benefits of MDCT include the ability to rapidly acquire the images, perform multiplanar and 3D reconstructions, and assess the adjacent soft tissues and bones. Rapid intravenous injection of iodinated contrast material is required for optimal arterial enhancement. CTA manifestations of an arterial injury may be direct, and include active contrast extravasation, pseudoaneurysm, arteriovenous fistula (AVF), intimal injury, dissection, or occlusion. There are also indirect signs which have a high association with vascular injury, and should raise suspicion, when present. Pitfalls related to image acquisition or patient factors can be mitigated with appropriate planning and post-processing techniques.

CT and MR imaging of the upper extremity vasculature: pearls, pitfalls, and challenges

Imaging is needed for diagnosis, treatment planning, and follow-up of patients with pathologies affecting upper extremity vasculature. With growth and evolution of imaging modalities [especially CT angiography (CTA) and MR angiography (MRA)], there is need to recognize the advantages and disadvantages of various modalities and obtain the best possible imaging diagnostic test. Understanding various limitations and pitfalls as well as the best practices to minimize and manage these pitfalls is very important for the diagnosis. This article reviews the upper extremity arterial vascular anatomy, discusses the CTA and MRA imaging, various pitfalls, and challenges and discuss imaging manifestations of upper extremity arterial pathologies.

Efficacy of fine focal spot technique in CT angiography of neck

OBJECTIVES

Focal spot size partially defines spatial resolution of a CT system. Many CT tubes have two focal spot sizes, with the finer one allowing more detailed imaging at the cost of photon intensity and increased heat production. Improved X-ray technology and advancement of various generations of iterative reconstruction allow the use of fine focal spot technique in CT angiography. CT neck angiography (CTNA) has been commonly performed as part of stroke imaging or in the trauma setting. This prospective study aimed to assess the efficacy of fine focal spot scanning in vessel clarity improvement, vessel calcification and arterial pulsation artefact reduction on CTNA.

METHODS AND MATERIALS

Consecutive adult patients of all ages and genders who presented for CTNA were included. All CTNA were scanned with standard focal spot size (SFSS) of 1 × 1 mm in first 4 months while the CTNA in the following 4 months with fine focal spot size (FFSS) of 0.5 × 1 mm. Vessel clarity, calcification and arterial pulsation artefact of arch of aorta, brachiocephalic, subclavian, common carotid, carotid bifurcation, internal carotid, external carotid and vertebral arteries were assessed randomly using a 5-point scale by two blinded radiologists. Results were compared.

RESULTS

There were 43 patients (mean age 60) with 97 calcified arterial segments in SFSS and 48 patients (mean age 62) with 113 calcified arterial segments in FFSS. 30 % of patients had > 50% carotid artery stenosis. No occlusion or dissection was found in the remaining arteries. Mann-Whitney test showed FFSS performed significantly better for vessel clarity (U: 48238.50, p < .001,r: 0.556) and calcification artefact reduction (U: 2040.50, p < .001,r: 0.564). There was no significant reduction for arterial pulsation artefact.

CONCLUSION

Fine focal spot technique improves vessel clarity and reduces calcification blooming artefact in CTNA. These benefits may potentially improve the assessment of arterial luminal stenosis and vessel wall pathology, including plaque morphology.

ADVANCES IN KNOWLEDGE

Beam hardening artefact from calcification particularly in the vessel wall can often reduce the clarity of vessel lumen thus affect accurate assessment of luminal stenosis. Fine focal spot technique has the advantages of reducing beam-hardening artefact of vessel wall calcifications and improving vessel wall clarity, thus it may potentially improve the assessment of arterial luminal stenosis and vessel wall pathology, including plaque morphology. It may become an important CT imaging technique in near future.

ACR Appropriateness Criteria® Shoulder Pain-Traumatic

Traumatic shoulder pain is pain directly attributed to a traumatic event, either acute or chronic. This pain may be the result of either fracture (the clavicle, scapula, or proximal humerus) or soft-tissue injury (most commonly of the rotator cuff, acromioclavicular ligaments, or labroligamentous complex). Imaging assessment of traumatic shoulder pain begins with conventional radiography and, depending on physical examination findings, will require MRI or MR arthrography for assessment of soft-tissue injuries and CT for delineation of fracture planes. Ultrasound excels in assessment of rotator cuff injuries but has limited usefulness for assessment of the deep soft-tissues. CT angiography and conventional arteriography are helpful for assessment of vascular injury, and bone scintigraphy can be used in assessment of complex regional pain syndrome after traumatic shoulder injury. The American College of Radiology Appropriateness Criteria are evidence-based guidelines for specific clinical conditions that are reviewed annually by a multidisciplinary expert panel. The guideline development and revision include an extensive analysis of current medical literature from peer reviewed journals and the application of well-established methodologies (RAND/UCLA Appropriateness Method and Grading of Recommendations Assessment, Development, and Evaluation or GRADE) to rate the appropriateness of imaging and treatment procedures for specific clinical scenarios. In those instances where evidence is lacking or equivocal, expert opinion may supplement the available evidence to recommend imaging or treatment.

Extravascular findings during upper limb computed tomographic angiography focusing on undiagnosed malignancy

BACKGROUND

Computer tomography angiography (CTA) has been an established method for diagnostic vascular disease of lower limbs. Recently, the method is widely used for diagnosis of vascular pathologies in the upper limbs too. It also has increased the possibilities of this scans being reviewed by no specially trained radiologists. This increases the risk of incidental non vascular findings to be missed or misinterpreted. The study is focusing in the frequency of extravascular incidental finding (EVIF) and highlights the importance for both the reporting radiologist and the referring physician recognizing the frequency of EVIFs.

AIM

To analyse the frequency of EVIF identified on computed angiography (CT) of the upper limb.

METHODS

A total of 1383 CT angiographic studies of the peripheral arterial system were performed between August 2015 and August 2017. All upper limb CTAs (n = 79) were retrospectively reviewed for the presence of non-vascular incidental findings within the chest, abdomen/pelvis, musculoskeletal system or head and neck. These EVIFs were subsequently grouped into 3 categories based on clinical significance. EVIFs of immediate clinical relevance were included in category A, findings considered indeterminate but most likely benign were placed in category B, while incidental findings of no clinical significance were included in category C.

RESULTS

Complete imaging datasets were available in 74/79 (93.7%). Patient demographics included 39 (52.7%) females and 35 (47.2%) males with a mean age of 59 ± 19.5 years (range 19-93 years). A total of 153 EVIFs were reported in 52 patients (70.3%). Of these, 44 EVIFs (28.7%) were found in the chest, 83 (54.2%) in the abdomen, 14 (9.2%) in the musculoskeletal system and 9 (5.8%) in the head and neck. Thirteen EVIFs (8.4%) identified in 11 patients were noted to be of immediate clinical significance (Category A), 50 EVIFs (32.3%) were identified in 20 patients and were considered indeterminate but most likely benign, while the remaining 91 EVIFs (59.5%) identified in 21 patients were determined to be of no clinical significance (Category C). One index case of malignancy (1.3%) and four cases of new disseminated metastatic disease (5.4%) were identified.

CONCLUSION

Our study of upper limb CTA examinations demonstrated a frequency of 8.4% for extravascular incidental findings of immediate clinical significance. We highlight the importance for both the reporting radiologist and the referring physician of the need to recognize the frequency with which EVIFs are identified in the upper limb peripheral arterial system and of the necessity for further clinical and imaging work-up.

Role of lower extremity run-off CT angiography in the evaluation of acute vascular disease

In the acute care setting, radiologists are frequently asked to assist in the evaluation of patients presenting with signs and symptoms of lower extremity peripheral vascular disease. Non-traumatic peripheral vascular emergencies are most commonly the result of thrombosis, either in a native vessel or within a bypass graft or stent. Arterial emboli, peripheral aneurysm with embolus or thrombosis, and direct arterial trauma are additional, less common causes. Traumatic peripheral vascular emergencies include vessel occlusion, transection, pseudoaneurysms, active extravasation, and arteriovenous fistulas. The high morbidity and mortality associated with acute limb ischemia makes rapid diagnosis and early initiation of therapy critical in the management of such patients. Computed tomographic angiography (CTA) offers the vascular specialist a rapid, widely available, and accurate means to diagnose and grade the extent of vascular disease in the acute care setting. In this pictorial essay, the key elements of lower extremity run-off CTA are reviewed, including relevant anatomy, imaging approach, and spectrum of imaging findings.

Evaluation of the diagnostic value of a venous phase in CT angiography of the extremities in the setting of trauma: is vein imaging in vain?

PURPOSE

This study examined the value of including a venous phase in addition to the initial arterial phase in the CT angiography evaluation of extremity trauma.

METHODS

CT studies from 157 patients (average age 38 years, age range 18-89 years, male 83%, female 17%) were obtained for trauma to the upper or lower extremity with both arterial and venous phases and retrospectively reviewed. The detection rate and type of vascular injury were evaluated by using the arterial phase alone and compared to the detection rate when interpreting the arterial and venous phases together.

RESULTS

Arterial injury was identified in 35 cases (22%), and venous injury was identified in seven cases (5%). Four cases of discrepant diagnoses were identified between image interpretation of the arterial phase alone and interpretation using both phases, all of which were venous injuries that were visible only on the venous phase. None of the four cases of venous injury required a change in surgical management. Overall, no significant difference in diagnosis between the two methods of image interpretation (arterial phase alone, arterial and venous phases) was discovered (p > 0.125; CI 95%).

CONCLUSIONS

The use of a venous phase in the CT angiography evaluation of extremity trauma does not add significant arterial diagnostic or clinical management value despite its potential of increasing the diagnostic detection rate of venous injury.

Upper Extremity Runoff: Pearls and Pitfalls in Computed Tomography Angiography and Magnetic Resonance Angiography

Upper extremity vasculature can be affected by various traumatic and nontraumatic pathologies; however, the evaluation of these arteries can be challenging for the radiologists as well as for the clinicians. After an accurate history and clinical examination, imaging plays a vital role in the diagnosis and treatment planning of these patients. Depending on the urgency and the indication, upper extremity arteries may be evaluated by ultrasonography with color Doppler, computed tomography (CT), magnetic resonance imaging (MRI), or digital subtraction angiography. This review article discusses relevant imaging anatomy of the upper extremity arteries, presents CT and MRI protocols, briefly describes the state-of-the-art CT and MRI of various pathologies affecting the upper extremity arteries, and summarizes the important pearls needed for busy practicing radiologist.

Acute Arterial Thrombosis of the Hand

Arterial thrombosis of the hand occurs infrequently but may result in considerable morbidity and compromise of hand function. The hand surgeon may be called upon to direct management in cases of acute arterial thrombosis of the hand and should have an understanding of the available diagnostic tools and treatment modalities. This article discusses the vascular anatomy of the hand and clinical manifestations of arterial thrombosis. Differences between isolated thrombosis and diffuse intravascular injury are detailed, and treatment options for these conditions are described. Appropriate care often requires coordination with interventional radiologists or vascular surgeons. Outcomes after treatment of arterial thrombosis of the hand are variable, and prognosis may be related to whether isolated thrombosis or diffuse intravascular injury is present.

Use of diagnostic modalities for assessing upper extremity vascular pathology

Vascular pathology of the upper extremity requires consideration of constitutional, anatomic, and functional factors. The medical history and physical examination are essential. The Allen test can be performed alongside a handheld Doppler for arterial mapping. Useful studies include digital-brachial index measurements, digital plethysmography, laser Doppler, and color ultrasounds. Three-phase bone scintigraphy still plays a role in the evaluation of vascularity after of frostbite injury. Angiogram remains the gold standard radiographic instrument to evaluate vascular pathology of the upper extremity, but computed tomography and magnetic resonance scans have an increasing role in diagnosis of vascular pathology.

Interpretation of upper extremity arteriography: vascular anatomy and pathology [corrected]

Understanding the utility and interpretation of upper extremity angiography is critical for the hand surgeon treating vaso-occlusive diseases of the hand. Although invasive and requiring the use of contrast dye, it remains the gold standard for imaging of the vascular system of the upper extremity. Angiography may detect numerous variants of the upper limb arterial system which may contribute to surgical pathology. Extensive vascular collateralization helps to maintain perfusion to the hand and facilitates reconstruction of the upper extremity. It is paramount to remember that angiography is a dynamic study and should represent a "flexible roadmap" for surgical reconstruction.

Efficacy of 'fine' focal spot imaging in CT abdominal angiography

OBJECTIVES

To assess the efficacy of fine focal spot imaging in calcification beam-hardening artefact reduction and vessel clarity on CT abdominal angiography (CTAA).

METHODS

Adult patients of any age and gender who presented for CTAA were included. Thirty-nine patients were examined with a standard focal spot size (SFSS) of 1 × 1 mm in the first 3 months while 31 consecutive patients were examined with a fine focal spot size (FFSS) of 1 × 0.5 mm in the following 3 months. Vessel clarity and calcification beam-hardening artefacts of the abdominal aorta, celiac axis, superior mesenteric artery, inferior mesenteric artery, renal arteries, and iliac arteries were assessed using a 5-point grading scale by two blinded radiologists randomly.

RESULTS

Cohen's Kappa test indicated that on average, there was substantial agreement among reviewers for vessel wall clarity and calcification artefact grading. Mann-Whitney test showed that there was a significant difference between the two groups, with FFSS performing significantly better for vessel clarity (U, 6481.50; p < 0.001; r, 0.73) and calcification artefact reduction (U, 1916; p < 0.001; r, 0.77).

CONCLUSION

Fine focus CT angiography produces images with better vessel wall clarity and less vessel calcification beam-hardening artefact.

KEY POINTS

Focal spot size affects the spatial resolution of a CT system. Fine focus CTAA produces images with improved vessel wall clarity. Fine focus CTAA is associated with fewer calcification beam-hardening artefacts. Fine focus CTAA may improve accuracy in assessment of luminal stenosis.