Color Doppler and Duplex Sonography in 5 Patients With Thoracic Outlet Syndrome

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1 Case Series Color Doppler and Duplex Sonography in 5 Patients With Thoracic Outlet Syndrome Raju Wadhwani, DMRD, DNB, Nitin Chaubal, MD, Rajan Sukthankar, MD, Manu Shroff, MD, Sanjay Agarwala, MS Purpose. To evaluate the use of color Doppler sonography in the diagnosis of thoracic outlet syndrome. Methods. We studied color Doppler sonographic findings in 5 clinically suspected cases of thoracic outlet syndrome. The subclavian artery and vein were studied in varying degrees of abduction to assess the severity of the syndrome. Results. Significant changes, i.e., stages of increased velocities, preocclusion, and occlusion in the subclavian artery in varying degrees of abduction, were noted in 4 of 5 cases. Blunted flow in the axillary artery (4 patients) and a rebound increase in velocities on release of abduction were noted in 3 patients. These changes suggested that significant narrowing was causing symptoms. Conclusion. Color Doppler sonography is a noninvasive, effective method compared with digital subtraction angiography in the diagnosis of thoracic outlet syndrome. Key words: color Doppler sonography; thoracic outlet syndrome; vascular sonography. Abbreviations DSA, digital subtraction angiography; PSV, peak systolic velocity; SCA, subclavian artery; TOS, thoracic outlet syndrome Received February 29, 2000, from the P. D. Hinduja National Hospital and Medical Research Centre, Mumbai, India. Revision requested May 3, Revised manuscript accepted for publication January 23, Address correspondence and reprint requests to Raju Wadhwani, DMRD, DNB, Department of Radiology, P. D. Hinduja National Hospital and Medical Research Centre, Veer Savarkar Marg, Mahim, Mumbai , India. Thoracic outlet syndrome (TOS) is a complex of signs and symptoms caused by compression of the vital neurovascular structures at the thoracic outlet region. This term was first coined by Peete et al in The causative factor is either an osseous or a soft tissue component, the most common being the cervical rib, first-rib abnormalities, and congenital bands and ligaments. The basic symptoms are related to compression of the brachial plexus and subclavian vein and artery. Diagnosis is usually made on the basis of clinical tests, radiography, electromyography, color Doppler sonography, and digital subtraction angiography (DSA). Little has been written about the color Doppler findings of this entity. We describe 5 cases of TOS and its diagnosis made on the basis of color-coded Doppler sonography. The key Doppler findings were changes in the subclavian artery (SCA) during different maneuvers, which have already been described in the literature, i.e., increased velocities in the SCA and blunted flow in the axillary artery on 2001 by the American Institute of Ultrasound in Medicine J Ultrasound Med 20: , /01/$3.50

2 Thoracic Outlet Syndrome abduction. However, the important findings that we will emphasize are the different stages, i.e., narrowing, preocclusion, occlusion, and a rebound increase in velocities with spectral broadening in the SCA on release of abduction. Patients and Methods Five patients (mean age, 21 years) underwent color Doppler examinations. The study included 3 women and 2 men. The predominant symptom in our patients was pain in an arm, especially on abduction. Numbness and weakness of the upper extremity were seen in 3 cases. On clinical examination, results of Adson s and hyperabduction maneuvers were positive for TOS in all cases. A positive Adson s maneuver result is marked by obliteration of the radial pulse when the head is turned to the affected side and the neck is extended during breath holding. The hyperabduction maneuver also has radial pulse obliteration as its end point. 2 Three patients had bilateral symptoms and 2 had unilateral symptoms (Table 1). For patients with bilateral symptoms, color Doppler sonography was first performed on the side with severe symptoms and then compared with color Doppler sonography of the opposite side. Color Doppler sonography was performed with a 7.5-mHz linear high-frequency probe and a GE Logiq 500 system (GE Medical Systems, Milwaukee, WI) or an ATL HDI Ultramark 9 system (ATL Ultrasound, Bothell, WA). The patients were examined in the sitting position. The subclavian, axillary, brachial, and forearm veins were scanned by color Doppler sonography for evidence of thrombi. Sonography was performed to look for compressibility of the vein in the arm and forearm. This was followed by color Doppler sonography of the subclavian, axillary, brachial, radial, and ulnar arteries to look for evidence of narrowing or thrombi. Dynamic studies were then performed. The SCA was assessed at the thoracic outlet by color Doppler sonography in a neutral position, at 90 abduction, at 120 abduction, in a hyperabduction position, and on release of abduction. Peak systolic velocities were calculated in these positions. Analysis of the waveform was performed on release of abduction. The axillary artery was also assessed in the abduction position, and peak systolic velocities (PSVs) were calculated in the neutral and abduction positions. The results of Doppler sonography were recorded on black-and-white film and color prints. The technique involved placing the transducer beneath the clavicle, and a longitudinal view of the subclavian artery and vein was obtained (in the costoclavicular space). On color Doppler sonography, narrowing was seen as turbulence and color aliasing in the SCA on 90 abduction. Complete absence of color flow was noted on hyperabduction. The normal velocities in the SCA in the neutral position were 50 to 100 cm/s; on abduction the velocities increased 2 to 3 times. In the preocclusion stage (120 abduction), flow velocity waveforms were obtained, i.e., half the normal values of velocities followed by occlusion (complete absence of flow in the hyperabduction position). On average, 3 waveforms were analyzed in a series, and average PSV was calculated; i.e., 3 peaks were averaged. The waveforms were acquired during maneuvers as real-time studies, i.e., 90, 120, and 135 abduction and hyperabduction. Peak systolic velocities were calculated. Table 1. Patients Symptoms and Treatment of TOS Patient Clinical Symptoms Age, y Sex Location of Symptoms Treatment 1 Pain in shoulder and 21 F Bilateral Surgery, Roos procedure arm on abduction (on left side) for scalene (more on left) muscle hypertrophy 2 Pain and weakness 26 M Bilateral Conservative of upper extremity (more on left) 3 Pain and numbness 21 F Unilateral Surgery, fibrous bands found of upper extremity 4 Shoulder pain 25 M Bilateral Conservative (more on right) 5 Pain and weakness 22 F Unilateral Surgery, anomalous rib on abduction operation (on left side) 796 J Ultrasound Med 20: , 2001

3 Wadhwani et al Presets for color Doppler sonography were as follows. A 7.5-mHz linear high-frequency probe was used. The velocity scale (i.e., pulse repetition frequency) and the filter were adjusted to get the maximal color and filter without tissue noise. The Doppler angle selected was constant at 60 during all waveforms. The persistence and frame rate were set on medium mode. The color sensitivity was adjusted with a low wall filter. Results Subclavian Artery These tests were performed in 5 control subjects and 5 symptomatic patients. The velocity criteria and other findings were correlated in both sets of patients. The normal velocities in the SCA were 50 to 100 cm/s. The velocities in the neutral position and on 120 abduction, 180 abduction, and hyperabduction were calculated. No significant change in velocities and other findings as mentioned below were noted during different maneuvers in control subjects (Table 2). Examination of the SCA by Doppler sonography in all symptomatic patients revealed the following findings. On Doppler examination, there was evidence of doubling of PSV in the SCA on 90 abduction (Fig. 1). Total obliteration of flow was noted on hyperabduction (Fig. 2); between the 2 stages was a stage of preocclusion, i.e., on 120 abduction, during which velocities decreased (Fig. 3). These 3 stages were noted in 4 of our 5 patients. A decrease in PSV in the axillary artery on hyperabduction due to proximal narrowing in the SCA (Fig. 4), suggesting significant compression, was noted in 4 patients. A rebound increase in PSVs and spectral broadening in the SCA on release of hyperabduction (Fig. 5) was noted in 3 of our 5 patients. This finding may suggest significant vascular compromise (Table 3). None of our patients had thrombi in the subclavian and axillary vessels. Angiography (Fig. 6) confirmed the color Doppler findings in 3 of our patients. Angiography revealed a complete cutoff of the SCA at the thoracic outlet on the hyperabduction (Lang s) maneuver (Table 4). Table 2. Changes in the SCA in Control Subjects PSV in SCA, cm/s Release of Abduction Hyper- Spectral Patient Neutral abduction PSV, cm/s Broadening None None None None Minimal Figure 1. Pulsed Doppler image showing an increase in PSV in the SCA on abduction. On the right, the increase in PSV (156 cm/s) in the SCA on abduction is shown; on the left, normal PSV (59 cm/s) in the SCA during the neutral position is shown. Figure 2. Pulsed Doppler image showing total obliteration of flow on hyperabduction in the SCA. On the left, high PSV in the SCA on abduction is shown; on the right, complete obliteration of flow on hyperabduction is shown. J Ultrasound Med 20: ,

4 Thoracic Outlet Syndrome Figure 3. Pulsed Doppler image showing normal PSV in the neutral position on the left and a decrease in PSV in preocclusion on the right. Subclavian Vein All patients had compression of the subclavian vein during arm abduction. A normal venous waveform was noted in the neutral position; however, a significant increase in velocities with loss of atrial and respiratory dynamics on 90 abduction was noted in 4 patients (Fig. 7), suggesting significant compression. Cessation of flow was noted on hyperabduction. However, in the remaining 2 patients, the normal atrial and Figure 4. Pulsed Doppler image showing systolic blunting in the axillary artery on hyperabduction. On the left, high systolic PSV (144 cm/s) in the SCA on abduction is shown; on the right, a blunted systolic peak with a decrease in PSV (81 cm/s) in the axillary artery on abduction is shown. respiratory dynamics were maintained in the vein, with increased velocities on abduction and cessation of flow on hyperabduction suggesting mild compression. A thrombus in the subclavian vein was not noted in any of our patients; however, venography was not performed in any of them. Color Doppler sonography revealed turbulence and aliasing, suggesting narrowing in the subclavian vein on 90 abduction (Fig. 8). Of 5 patients, 3 had surgery and 2 had conservative treatment. Of the 3 patients who had surgery, 1 had an anomalous rib, 1 had fibrous bands, and 1 had scalene muscle hypertrophy. The patient with scalene muscle hypertrophy had improvement after the Roos procedure (transaxillary first rib resection). Clinical improvement confirmed the diagnosis in all patients who had curative surgery. At follow-up Doppler examination, normal systolic velocities were noted on hyperabduction (Fig. 7). A total of 8 upper limbs were studied in 5 patients. A significant compromise as evident on color Doppler sonography was noted in 4 upper limbs, of which 3 were treated surgically and 1 was treated conservatively. Discussion Thoracic outlet syndrome is an underrated, overlooked, and misdiagnosed important but difficult-to-treat syndrome. 3 The thoracic outlet is the space between the rib cage and the clavicle through which the main blood vessels and nerves pass from the neck and thorax into the arm between the 2 scalene muscles; the structures are the brachial plexus and the subclavian artery and vein. Thus the causative factor could be bone or soft tissue. Bone factors leading to TOS comprise the cervical rib in 5% to 91% of cases, first rib abnormalities, fracture of the first rib and clavicle, and a prominent transverse process at C7. 3 Soft tissue components comprise congenital bands and ligaments and acquired scalene muscle changes. Symptoms are primarily attributable to compression of the brachial plexus and the subclavian artery and vein. The syndrome is characterized by a combination of pain, numbness, tingling, weakness, a cold upper extremity, and swelling of the extremity. On clinical examination, positive results of Adson s test and the hyperabduction maneuver are the criteria for diagnosing TOS; how- 798 J Ultrasound Med 20: , 2001

5 Wadhwani et al ever, false-positive rates for these tests are known. 4 Plain radiographs of the cervical spine and chest are taken to rule out cervical rib and first rib abnormalities. 4 Little has been mentioned about the role of color Doppler sonography in the evaluation of TOS. Both arteries and veins have been examined in 1 color Doppler sonographic study during diagnostic maneuvers that cause vascular compression at the outlet. Color Doppler sonography of the subclavian artery and vein and the axillary artery is performed in the neutral position, at 90 and 120 abduction, and during hyperabduction. 5 The most important finding is doubling of PSV in the subclavian artery and vein on 90 abduction because of narrowing of the vessel. 6 Abduction beyond that degree, e.g., 120, leads to a decrease in flow, i.e., a decrease in PSV in the vessel because of the preocclusive stage. On hyper- Figure 5. Pulsed Doppler image showing a rebound increase in PSV on release of hyperabduction. On the left, normal PSV (94 cm/s) in the SCA is shown; on the right, high velocities (PSV, 156 cm/s; end-diastolic velocity, 57 cm/s) are shown, with spectral broadening in the SCA on release of abduction. Table 3. Changes on Doppler Sonography in 5 Cases of TOS PSV in SCA, cm/s Changes on Release of Abduction Hyper- Axillary artery Spectral Patient Neutral abduction blunting of waveform PSV, cm/s Broadening Absence of flow Present 156 Present Absence of flow Present 160 Present Absence of flow Present No findings* No findings* No findings* No findings* No findings* No findings* No findings* Absence of flow Present 164 Present *The test was performed, but findings were not present. Figure 6. A, Angiogram showing normal SCA in the neutral position. B, Angiogram showing complete cutoff of the SCA during the hyperabduction maneuver. A B J Ultrasound Med 20: ,

6 Thoracic Outlet Syndrome Table 4. Color Doppler Sonographic and DSA Findings Color Doppler Sonography SCA Subclavian Vein Patient Right Left Right Left DSA 1 Increase in velocities All 3 stages of narrowing, Mild increase Loss of atrial and Narrowing of subclavian on abduction, no preocclusion, and occlusion; in velocities respiratory dynamics artery during Adson s evidence of preocclusion blunted flow in axillary with increase in maneuver and occlusion stages artery; rebound increase velocities on in PSV in SCA on release abduction of abduction 2 As above As above As above As above Findings not noted 3 Findings not noted All 3 stages of narrowing, Findings not Loss of atrial and Findings not noted preocclusion, and occlusion; noted respiratory dynamics blunted flow in axillary artery with doubling of velocity 4 Increase in velocities on Doubling of velocities Increase in Increase in velocities Narrowing of subclavian abduction, evidence of on abduction, no velocities on abduction artery during Adson s preocclusion and evidence of occlusive stage on abduction maneuver occlusion 5 Findings not noted All 3 stages of narrowing, Findings not Loss of atrial and As above preocclusion, and occlusion; noted respiratory dynamics blunted flow in axillary artery; rebound increase in PSV in SCA on release of abduction with doubling of velocity abduction, complete cessation of flow is noted because of complete occlusion. This is seen in severe cases. On hyperabduction, a decrease in PSV with a blunted waveform, suggesting low flow in the axillary artery, is noted. 6 There is a Figure 7. Pulsed Doppler image showing normal PSV on hyperabduction postoperatively. On the left, normal PSV (97 cm/s) in the SCA in the neutral position is shown; on the right, the PSV is not increased on abduction (80 cm/s), suggesting a normal response postoperatively. rebound increase in PSVs and spectral broadening on release of the hyperabduction maneuver because of a sudden gush of flow through the narrowed segment. Similar findings were noted in the subclavian vein on Doppler sonography, with loss of atrial respiratory dynamics in some cases suggesting significant compression. An increase in velocities on abduction in the SCA and blunting of flow in the axillary artery have been reported in the literature as findings on color-coded Doppler sonography in TOS. 6 However, to our knowledge, the importance of the 3 different stages of narrowing, preocclusion, occlusion, and the rebound increase in velocities with spectral broadening on release of abduction in SCA have not been mentioned in the literature. Color Doppler sonography is also used to detect venous thrombosis in the subclavian and axillary veins seen in severe cases. It is noninvasive and cost-effective without the effects of ionizing radiation, unlike DSA. Color Doppler sonography also plays an important role in postoperative evaluation of these patients, as shown by the normal velocities on hyperabduction. Magnetic resonance angiography shows the anatomy of the brachial plexus J Ultrasound Med 20: , 2001

7 Wadhwani et al References 1. Roos DB. Historical perspectives and anatomic considerations. Thoracic outlet syndrome. Semin Thorac Cardiovasc Surg 1996; 8: Hurst LC, Paul S. Thoracic outlet syndrome: peripheral nerve injuries and entrapments. In: Dee R, Mango E, Hurst LC (eds). Principles of Orthopedic Practice. Vol 1. New York: McGraw-Hill; 1988: Atasoy E. Thoracic outlet compression syndrome. Orthop Clin North Am 1996; 27: Figure 8. Pulsed Doppler image showing the presence of normal color flow in the left subclavian vein (left) and turbulent flow with aliasing in the vein on abduction (right). and subclavian vessels well, but it cannot show vascular compression, because dynamic studies are not possible. Treatment of TOS is either conservative or surgical. Conservative treatment comprises exercises 8 and is used in all cases except those in which patients have long-standing or obvious neurologic symptoms and signs of vascular compression. Surgical treatment consists of combined transaxillary first rib resection and cervical scalenectomy during the same operation to achieve the best possible results for total decompression of the thoracic outlet region and to reduce the chance of recurrence. In conclusion, we have described the role of color Doppler sonography in TOS. In all 5 patients, altered hemodynamics in the subclavian artery and vein were shown on color Doppler studies; however the severity of the changes was different in these patients. The 2 additional findings mentioned above on colorcoded Doppler sonography (various findings at different stages of abduction and spectral broadening with an increase in velocities on release of abduction) may give us insight into the diagnosis of TOS on the basis of color Doppler studies. Although the number of patients was small, we hope that these findings will provide the basis for future prospective studies in more patients. 4. Plew MC, Delinger M. The false positive rate of thoracic outlet syndrome shoulder maneuvers in healthy subjects. Acad Emerg Med 1998; 5: Davidovic LB, Lotia SI, Vojnoric BR, et al. Treatment of thoracic outlet vascular syndrome. Srp Arh Celok Lek 1998; 126: Longley DG, Vedlicka JW, Molina EJ, et al. Thoracic outlet syndrome: evaluation of the subclavian vessels by color duplex sonography. AJR Am J Roentgenol 1992; 158: Esposito MD, Anignton JA, Blackshear MN, et al. Thoracic outlet syndrome in throwing outlet diagnosed with MRI and MRA. J Magn Reson Imaging 1997; 7: Novak CB. Conservative management of thoracic outlet syndrome. Semin Thorac Cardiovasc Surg 1996; 8: J Ultrasound Med 20: ,