Three-dimensional MR angiography in the evaluation of thoracic outlet syndrome.

OBJECTIVE: The objective is to present our initial experience with the combination of three-dimensional time-resolved contrast-enhanced MR angiography and T1-weighted spin-echo imaging for investigation of vascular compression related to thoracic outlet syndrome. CONCLUSION: In patients with clinical signs of thoracic outlet syndrome suggesting vascular elongation or compression, this technique proves to be robust, and its results are comparable to those of conventional catheter angiography. Our results allow precise identification of the anatomic structure(s) responsible for the clinical symptoms and show the effect of arm hyperabduction on the patency of the subclavian vessels.     

Thoracic outlet syndrome in a throwing athlete diagnosed with MRI and MRA

Thoracic outlet syndrome comprises the clinical manifestations in the arm caused by compression of the neuro-vascular bundle as it leaves the thoracic inlet. The neuro-vascular bundle is composed of the subclavian artery, the subclavian vein, and the bra-chial plexus. The symptoms of thoracic outlet or inlet syndrome are most often caused by compression of the nerves of the brachial plexus, which is involved in up to 98% of cases; the remainder are due to vascular compression. MRI with MRA demonstrates well the anatomy of the brachial plexus as well as any vascular compression or occlusion. The relationship of the axillary and subclavian vein to the first rib and subclavius muscle also can be demonstrated. We present a college baseball player who presented with numbness in the fingers of his throwing hand when throwing a baseball. Evaluation with spin-echo and two-dimensional time-of-flight MR angiographic (MRA) imaging of the thoracic outlet region revealed obstruction of the subclavian vein with the arm abducted. To our knowledge, no such cases have been diagnosed previously with MRI.     

Subclavian steal phenomenon: a correlation between duplex sonographic and angiographic findings

Summary Correlation of duplex sonography, angiography of the vertebral artery, and the degree of subclavian or innominate stenosis was carried out in ten patients with the subclavian steal phenomenon. Four successive stages of Doppler waveform were identified by duplex sonography. Three angiographic patterns of decreasing severity, permanent reversal, to-and-fro motion and delayed opacification, were found. Permanent reversal angiograms corresponded to complete reversal or late transient Doppler waveforms. To-and-fro motion and delayed opacification angiograms did not necessarily have a corresponding Doppler pattern. The different stages of subclavian steal phenomenon on duplex sonography correlated significantly with the degree of subclavian or innominate stenosis. Stenosis of at least 60% was found to produce abnormal vertebral artery Doppler sonography, except in one patient. Duplex sonography is considered to be a sensitive and convenient method for detecting abnormal vertebral artery haemodynamics and the subclavian steal phenomenon, but some other factors may be important in producing the Doppler waveforms.     

MR angiography of thoracic outlet syndrome.

Thoracic outlet syndrome is a disorder caused by neurovascular compression of the brachial nerve plexus and the subclavian artery or vein by bones and muscles. We report the MR angiographic findings of a patient with thoracic outlet syndrome.     

Correlation of contrast-enhanced power Doppler sonography and conventional angiography of abduction-induced hip ischemia in piglets

OBJECTIVE: The purpose of this study was to determine if enhanced power Doppler sonography can detect early ischemia of the capital femoral epiphysis induced by hip hyperabduction in piglets and to correlate these findings with angiography. MATERIALS AND METHODS: Proximal femoral perfusion was evaluated in 18 studies of 10 piglet hips with unenhanced power Doppler sonography, enhanced power Doppler sonography with IV contrast agent, and digital angiography, in neutral position, hyperabduction, and after release to neutral position. Enhancement ratios between pixel intensities of power Doppler sonography and enhanced power Doppler images in each position were calculated. Angiograms were analyzed for differences in flow with changes in hip position. RESULTS: With the piglet in neutral position, power Doppler sonography revealed few vessels in the femoral head. Contrast administration resulted in a temporary marked increase in the visualization of vessels in the femoral head. Quantitative enhanced power Doppler sonography revealed a marked decrease in pixel intensity with abduction (p < 0.001) that was not apparent on unenhanced studies (p = 0.28). The enhancement ratio decreased from 0.45 (mean +/- SD, +/- 0.26) in neutral position to 0.10 (+/- 0.21) after abduction; it returned to 0.41 (+/- 0.14) after release of abduction (p < 0.001 for each comparison). Angiographic studies in hyperabduction revealed a variable level of ischemia. CONCLUSION: Enhanced power Doppler sonography can be used to visualize the vascular supply to the cartilaginous femoral head in piglets and can detect reversible ischemia induced by hip hyperabduction. These differences correlate with digital angiographic evidence of ischemia.     

Angiographic positions for thoracic outlet syndrome

Thirty four patients (18 males and 16 females, 54 lesions) with thoracic outlet syndrome (TOS) were studied with conventional angiography. Angiography in the supine position did not confirm subclavian artery compression in 43.4% of patients. Lordotic position or upright position was useful for demonstration of subclavian artery compression in patients who did not show any findings in conventional techniques.     

A case of venous thoracic outlet syndrome recognized by arm swelling

Most cases of thoracic outlet syndrome are detected by neulogical symptoms, and most of the other symptoms are caused by arterial stenosis. It is rare for the syndrome to be recognized by venous symptoms. We report a 56-year-old woman with thoracic outlet syndrome recognized by arm swelling. She was admitted for radiation therapy of a recurrent tumor of lung cancer at the left apex. Her right arm gradually became swollen. We performed venography from the right median cubital vein because of suspected venous thrombosis. Venography revealed stenosis of the right subclavian vein at the costoclavicular space, and this finding was confirmed by helical CT. These findings strongly support our diagnosis of thoracic outlet syndrome.     

Arterial abnormalities of the shoulder in athletes

Vascular lesions of the shoulder may be misinterpreted as one of the more familiar shoulder abnormalities by a treating physician. We are reporting on 13 athletes who were found to have symptoms related to compression of the subclavian or axillary artery or their tributaries. Nine were amateur or professional baseball pitchers. Severe arm fatigue or finger ischemia, secondary to embolization, were presenting symptoms. Arm fatigue was noted in all pitchers. After complete history and physical examination, including auscultation for bruits in functional positions, all athletes were evaluated by noninvasive tests (Doppler and Duplex scanning). Arteriography was performed with positional testing, recreating overhead activity, and complete radiographic visualization of the dye to the digital arteries. Two patients were found to have subclavian artery aneurysm. The remaining athletes were found to have compression of the subclavian artery beneath the anterior scalene muscle (five patients), the axillary artery beneath the pectoralis minor (two patients), both arterial segments (two patients), and one was found to have arterial compromise at the level of the humeral head. Branch artery compression was also noted. One pitcher occluded the posterior circumflex humeral artery with embolization to the digit. The two patients with subclavian aneurysms underwent saphenous vein bypass with cervical rib resection. All of the other athletes except one underwent resection of a 2 to 3 cm segment of the anterior scalene muscle or pectoralis minor muscles. All returned to their previous level of activity except one patient who developed impingement type symptoms and required acromioplasty. He is currently undergoing rehabilitation. Proper recognition of vascular compromise in the upper extremity of athletes is essential to avoid the catastropic complications of arterial thrombosis.     

Functional anatomy of extracranial arteries in occlusive vascular diseases by direct continuous wave Doppler sonography

Doppler sonography of supratrochlear and neck arteries permits a determination of the direction and speed of flow. By compression of distal branches, the external carotid artery can be recognized, the occipital artery can be distinguished from the vertebral, and the direction of flow in the supratrochlear artery can be ascertained regardless of the artery's coiling. Compression of the arm can reveal subclavian steal. In order to localize a stenosis the vessel is followed by the probe. The accuracy of Doppler sonography is approximately 96%, and while the method may miss the diagnosis of slight stenoses and ulcerations, it nevertheless appears to be superior to all other indirect, noninvasive techniques that are currently available.     

"Effort" thrombosis of the subclavian vein in a competitive swimmer

"Effort" thrombosis is a unique form of subclavian and axillary vein thrombosis because it is the result of an unusual variant of the thoracic outlet syndrome. Another cause of subclavian vein thrombosis is local compression from trauma, tumor, or development anomalies; a third is intimal damage from indwelling central venous catheters. This is a case report of "effort" thrombosis of the subclavian vein in a competitive swimmer. A recently developed technique of local infusion of low-dose streptokinase therapy is used for clot lysis. Early diagnosis is essential for effective thrombus dissolution with streptokinase. The rationale, risk, and method of streptokinase administration are discussed. Since "effort" thrombosis is secondary to thoracic outlet syndrome (TOS), decompression of the thoracic outlet by removal of the first rib after clot lysis is recommended.     

Functional imaging of the thoracic outlet syndrome in an open MR scanner

Symptoms due to thoracic outlet syndrome may present only in abduction, a position that cannot be investigated in conventional MR scanners. Therefore, this study was initiated to test MRI in an open magnet as a method for diagnosis of thoracic outlet syndrome. Ten volunteers and 7 patients with a clinical suspicion of thoracic outlet syndrome were investigated at 0.5 T in an open MR scanner. Sagittal 3D SPGR acquisitions were made in 0 and 90 ° abduction. In the patients, a similar data set was also obtained in maximal abduction. To assess compression, the minimum distance between the first rib and the clavicle, measured in a sagittal plane, was determined. In the neutral position, no significant difference was found between patients and controls. In 90 ° abduction, the patients had significantly smaller distance between rib and clavicle than the controls (14 vs 29 mm; p < 0.01). On coronal reformatted images, the compression of the brachial plexus could often be visualised in abduction. Functional MR examination seems to be a useful diagnostic tool in thoracic outlet syndrome. Examination in abduction, which is feasible in an open scanner, is essential for the diagnosis. Received: 22 February 1999; Revised: 15 June 1999; Accepted: 30 June 1999     

锁骨下动脉窃血综合征的彩色多普勒超声与CTA的对比研究

目的探讨锁骨下动脉窃血综合征的彩色多普勒超声与CTA特征及诊断价值。方法回顾性分析2l例锁骨下动脉(subclavian artery,SCA)窃血综合征患者的超声及CTA资料,并进行对照分析。结果锁骨下窃血综合征发生于左侧病变l4例,右侧7例,其中部分窃血6例,完全窃血14例,其中锁骨下动脉起始部闭塞5例。患侧椎动脉反向程度与该侧锁骨下动脉或无名动脉狭窄程度与CTA对照呈正相关。结论椎动脉反流是诊断锁骨下动脉窃血综合征的重要依据之一,也是超声多普勒诊断锁骨下动脉窃血综合征的优势。锁骨下动脉管腔的真实狭窄程度CTA具有绝对的优势。     

MRI findings in thoracic outlet syndrome

We discuss MRI findings in patients with thoracic outlet syndrome (TOS). A total of 100 neurovascular bundles were evaluated in the interscalene triangle (IS), costoclavicular (CC), and retropectoralis minor (RPM) spaces. To exclude neurogenic abnormality, MRIs of the cervical spine and brachial plexus (BPL) were obtained in neutral. To exclude compression on neurovascular bundles, sagittal T1W images were obtained vertical to the longitudinal axis of BPL from spinal cord to the medial part of the humerus, in abduction and neutral. To exclude vascular TOS, MR angiography (MRA) and venography (MRV) of the subclavian artery (SA) and vein (SV) in abduction were obtained. If there is compression on the vessels, MRA and MRV of the subclavian vessels were repeated in neutral. Seventy-one neurovascular bundles were found to be abnormal: 16 arterial-venous-neurogenic, 20 neurogenic, 1 arterial, 15 venous, 8 arterial-venous, 3 arterial-neurogenic, and 8 venous-neurogenic TOS. Overall, neurogenic TOS was noted in 69%, venous TOS in 66%, and arterial TOS in 39%. The neurovascular bundle was most commonly compressed in the CC, mostly secondary to position, and very rarely compressed in the RPM. The cause of TOS was congenital bone variations in 36%, congenital fibromuscular anomalies in 11%, and position in 53%. In 5%, there was unilateral brachial plexitis in addition to compression of the neurovascular bundle. Severe cervical spondylosis was noted in 14%, contributing to TOS symptoms. For evaluation of patients with TOS, visualization of the brachial plexus and cervical spine and dynamic evaluation of neurovascular bundles in the cervicothoracobrachial region are mandatory.     

Thoracic outlet syndrome in aquatic athletes

Thoracic outlet syndrome is a well-recognized group of symptoms resulting from compression of the subclavian artery and vein, as well as the brachial plexus, within the thoracic outlet. Symptoms are related directly to the structure that is compressed. Diagnosis is difficult because there is no single objective, reliable test; therefore, diagnoses of thoracic outlet syndrome is based primarily on a set of historical and physical findings, supported and corroborated by a host of standard tests. Because aquatic athletes are primarily "overhead" athletes, one may expect a higher incidence of thoracic outlet syndrome in this population. The differential between TOS and "swimmer's shoulder" (multidirectional instability and subacromial impingement) may be difficult. Nonsurgical treatment methods can be helpful in relieving symptoms; in certain recalcitrant cases, however, surgical intervention can provide lasting relief and a return to aquatic athletics.     

Thoracic outlet syndrome: review and reference to stroke in a major league pitcher

The thoracic outlet compression syndrome is reviewed. It should be considered in all neurologic and vascular complaints of the upper extremity. Symptoms are related to arm position and use and are aggravated by sustained activity that stresses the shoulder. A participant in any sport that requires a repetitive violent throwing motion is a potential candidate for this condition. A detailed report of a major league pitcher illustrates the importance of early diagnosis and appropriate treatment, inasmuch as delay can be catastrophic, as in the case of this career athlete. A thorough history is the best aid in arriving at a diagnosis. When the symptoms are mild or moderate, conservative therapy may suffice. When surgery is indicated, the object is to create adequate space for passage of the brachial plexus, subclavian artery, and subclavian vein. Patients with thrombosis and occlusion of a major artery supplying the upper extremity require an additional arterial reconstructive procedure plus a cervicothoracic sympathectomy.     

Recurrent middle cerebral artery stroke caused by arterial thoracic outlet syndrome and coagulopathy

Thoracic outlet syndrome (TOS) is defined as compression of neurovascular components passing the thoracic outlet. While neurologic compression is the most common form, rare cases of arterial comprssion could result in concerning cerebral thromboembolic events. Here we present a 15-year-old female with repeated left hemiparesis and radiologic signs of cerebrovascular accident (CVA) in right middle cerebral artery. Further investigations revealed stenosis of the right subclavian artery, saccular aneurysm, and occlusion of the right brachial artery which suggested the diagnosis of arterial TOS. Based on this report, we present this diagnosis as a rare but important cause of CVA, especially in young patients.     

Positional occlusion of the descending scapular artery in transverse thoraco-brachial syndrome with neurologic symptoms

We report a thoracic outlet syndrome revealed by neurological complications. Angiography of the subclavian artery depicted an isolated positional occlusion of the descending scapular artery. This side branch of the subclavian artery is anatomically located close to and supplies the brachial plexus. Surgical treatment led to improvement of most symptoms and post-operative control angiography was normal. Not previously described, this sign illustrates the objective compression of the brachial plexus. Ischemia is perhaps intricated with compression, a well-known pathophysiological mechanism of neurological complications in this syndrome. This artery feeding the brachial plexus is usually ligated during surgical neurolysis but must be preserved in order to improve recovery of neurological function and prevent surgical failures.     

A prospective comparison of duplex sonography vs angiography of the vertebral arteries

A prospective blind comparison was completed between duplex sonography and angiography of the vertebral arteries. Thirty-two vertebral arteries were studied for direction of flow, degree of origin plaque or stenosis, Doppler characteristics, and vessel size. The vertebral arteries were reliably identified by imaging their course from the subclavian artery into the transverse foramina and by identifying a Doppler signal similar in waveform to the internal carotid artery. With Doppler, a 90% accuracy was obtained for direction of blood flow. Nonvisualization of origins was primarily due to vessel depth and/or tortuosity. In 12 vessel origins that were well seen with both techniques, angiography and sonography agreed in two-thirds of the cases. In four cases, origin plaque was underestimated with duplex imaging. Interestingly, no Doppler frequency or velocity elevation was identified distal to significant stenoses. One false-positive diagnosis of occlusion occurred with sonography, in which a 99% origin stenosis resulted in no detectable Doppler signal. By comparing sonography with angiography, sonography was shown to be 80% accurate in determining vertebral artery size. Our preliminary results indicate that duplex scanning is a reasonably accurate screening technique for size, patency, and direction of blood flow in the vertebral arteries. Duplex evaluation of the vertebral artery origin was limited by vessel depth, tortuosity, and calcifications.     

Pulsatile portal vein flow: a sign of tricuspid regurgitation on duplex Doppler sonography

Sonography and duplex Doppler frequently fail to identify a cause for right upper quadrant pain, liver dysfunction, or ascites. The aim of our study was to describe and analyze the pulsatile portal venous waveform in which minimum velocity dropped to or below zero on duplex Doppler sonography and to investigate its possible association with tricuspid regurgitation, one of the causes of liver dysfunction. We correlated the findings in 15 patients in whom this duplex Doppler waveform was seen with the findings on Doppler echocardiography (n = 14) or ultrafast CT (n = 1). All patients had biochemical liver abnormalities or sudden onset of ascites, rapid weight gain, increased abdominal girth, and hepatomegaly. They were referred for sonography to rule out liver metastases, biliary disease, portal vein thrombosis, or Budd-Chiari syndrome. All examinations were done with a 3-MHz phased-array sector transducer with duplex Doppler capability. Seventeen volunteers with no known liver or heart disease served as a control group. We correlated maximum and minimum flow velocities on the portal venous Doppler waveform with the portal vein diameters of the study and control groups. Thirteen patients were later proved to have tricuspid regurgitation, one patient had an aortic-right atrial fistula owing to rupture of an aneurysm of the sinus of Valsalva, and one patient was proved to be normal. In none of the 17 control subjects was this pulsatile portal venous waveform seen. Our study shows that detection of a pulsatile portal venous waveform on duplex Doppler sonography in patients with liver dysfunction should raise the possibility of tricuspid regurgitation.     

Thrombosis of upper extremity thoracic inlet veins: diagnosis with duplex Doppler sonography

Duplex Doppler sonography of the axillary, subclavian, internal jugular, and brachiocephalic veins was performed in 20 normal volunteers and in a series of 22 consecutive patients with suspected venous thrombosis. When normal, these vessels had hypoechoic or anechoic lumina, sharply echogenic walls, and characteristic Doppler flow patterns that varied with changes in intrathoracic pressure. Most thrombosed vessels had poorly defined walls and echogenic lumina. All had absent flow on Doppler analysis. Duplex Doppler sonography was positive in all 10 patients subsequently shown to have venous thrombosis by venography or CT. One false-positive result occurred in a technically limited study. Sonography has the advantages of portability, ease of performance, and high patient acceptance. Duplex Doppler has advantages over either continuous-wave Doppler or imaging sonography alone. Our experience suggests that duplex Doppler sonography should be the initial diagnostic study in evaluating suspected thrombosis of the upper extremity thoracic inlet veins.