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| Year : 2001 | Volume
: 11
| Issue : 2 | Page : 71-73 |
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| Sonographic approach to the superior mediastinum |
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S Ganesan
Department of Radiodiagnosis & Imaging INHS Asvini Colaba, Mumbai 400005, India
Click here for correspondence address and email
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Keywords: Ultrasound, Chest, Mediastinum
How to cite this article:
Ganesan S. Sonographic approach to the superior mediastinum. Indian J Radiol Imaging 2001;11:71-3 |
The use of US as an imaging tool in the evaluation of mediastinum has been overlooked to a large extent. With the advent of CT and MR mediastinal US has not been given adequate importance it actually deserves. We present our experiences with sonographic evaluation of the superior mediastinum from a large series of patients assessed in our institution over a period of last four years as a pictorial essay. Technical Considerations US evaluation of the superior mediastinum was carried out using a commercially available ultrasound machine equipped with Doppler applications as well. A high resolution, dual frequency (6.5 MHz / 5 MHz ) end firing, tightly packed curved array endovaginal probe with a small foot print of 10 mm radius of curvature and a beam angle of 900 was employed for assessing the superior mediastinum. Patients were examined in a supine position using a pillow placed under the shoulders. The neck was minimally extended and the chin flexed. A generous amount of acoustic coupling gel was used to provide adequate contact for the probe. Suprasternal and supraclavicular sites just lateral to the sternocleidomastoid on either side were used for obtaining adequate windows to the superior mediastinum. Semicoronal, sagittal, parasagittal and combination oblique views were easily obtained from suprasternal, paratracheal and supraclavicular windows. The major blood vessels of the neck and upper limbs along with the great vessels of the superior mediastinum serve as road maps for evaluating different anatomic subsites. Once an abnormality was localized to a particular territory the lesion was further evaluated for its structure of origin, nature, internal architecture and any other characteristics which may suggest a specific diagnosis.
 Discussion | |  |
The diagnostic value of mediastinal US has been overlooked to a great extent. The paucity of relevant literature with respect of mediastinal US bears ample testimony to this. High resolution US imaging of superior mediastinal pathology can play an adjunctive role to other imaging modalities such as chest radiographs, CT or MR [1]. Mediastinal US is a very sensitive imaging modality in the detection of abnormalities involving the prevascular, paratracheal and supraaortic areas. Similarly abnormalities along the superior vena cava, the paracaval area upto the right atrium, the right hilar region and the aortopulmonary window area can be demonstrated as well. The posterior mediastinum and paraspinal regions are beyond the reach of US. Once the abnormality is localised topographically, US can offer information with regards to its structure of origin, size, solid or cystic nature, internal architecture, calcification, areas of breakdown, necrosis, collection and any evidence of vascular compromise [1],[2],[3]. These sonographic characteristics along with the clinical presentation may suggest a specific diagnosis in a particular clinical setting [Figure - 1],[Figure - 2],[Figure - 3],[Figure - 4],[Figure - 5],[Figure - 6],[Figure - 7],[Figure - 8],[Figure - 9],[Figure - 10],[Figure - 11]
Superior mediastinal US may be employed as an effective preliminary imaging modality in a wide variety of clinical presentations. US can confirm or rule out the presence of a possible abnormality in patients presenting with a widened superior mediastinum on chest radiography. Similarly, US can also be used for studying superior mediastinal masses, for the evaluation of patients with cervical, supraclavicular and axillary lymphadenopathy, for contiguous mediastinal nodal extension and for follow up of known cases such as lymphoma, for monitoring response to treatment [4],[5]. Mediastinal US along with Doppler applications may find valuable and crucial information in suspected vascular masses and pseudo-masses [6]. US guidance can also be employed for performing biopsies / FNACs from abnormal areas or for aspiration of collections [7],[8]. High resolution imaging of the superior mediastinum is a sensitive imaging modality, of course with some limitations. However with careful attention to technique and positioning of the patient, most areas of superior mediastinum can be assessed, using arteries and veins as reference road maps. It must be reiterated that the value of US lies in its being economical, highly cost effective, easily available and a radiation free imaging modality.
| References | | |
| 1. | Wernecke K, Diederich S. Sonographic features of mediastinal tumors. AJR 1994; 163:1357-64  [PUBMED] |
| 2. | Wernecke K, Peters P, Galanski M. Mediastinal tumors. Evaluation with suprasternal US. Radiology 1986 ; 159: 405-409 |
| 3. | Ikezoe J, Morimoto S, Arizawa J et al. Ultrasonography of mediastinal teratoma. JCU 1986 ; 14 : 513-520 |
| 4. | Wernecke K, Varsalla P, Hoffman G, et al. Value of US in monitoring the therapeutic response of mediastinal lymphoma ; comparison with chest radiography and CT. AJR 1991;156: 265-272 |
| 5. | Margli SI, Laing FC, Castelino RA. Current status of mediastinal US in the post treatment evaluation of patients with lymphoma. AJR 1991;157:647-673 |
| 6. | Kasper W, Meinertz T, Kersting F, Lang K, Just H. Diagnosis of dissecting aortic aneurysm with superior mediastinal echocardiography. Am J Cardiol 1978; 42:291-294 |
| 7. | Gupta S, Gulati M, Raghuvanshi A, Gupta D, Suri S. Sonographically guided fine needle aspiration biopsy of superior mediastinal lesions by the suprasternal route. AJR 1998;171:1303-6 |
| 8. | Wernecke K, Vagallo P, Peters et al. Mediastinal tumours - biopsy under ultrasound guidance. Radiology 1989 ; 172 : 473-476 |
Correspondence Address:
S Ganesan
Department of Radiodiagnosis & Imaging INHS Asvini Colaba, Mumbai 400005
India
 Source of Support: None, Conflict of Interest: None  | Check |
Figures
[Figure - 1], [Figure - 2], [Figure - 3], [Figure - 4], [Figure - 5], [Figure - 6], [Figure - 7], [Figure - 8], [Figure - 9], [Figure - 10], [Figure - 11] |
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