Letter to the Editor: Mostbeck G. Elastography Everywhere – Now Even the Lungs! Ultraschall in Med. 2014; 35: 5 – 8

 

 Buy Article Permissions and Reprints

Abstract

Clinical ultrasound approaches should be driven by physio-pathology knowledge and with explicit and realistic diagnostic and therapeutic goals. Thoracic ultrasound is valuable for reaching early and affordable preliminary diagnosis and for safe interventional guidance of cavity evacuations or of fine needle aspiration biopsy (FNAB) procedures by the continuous visual control of the operator. Using thoracic ultrasound elastography, only squamous cell lung carcinoma displays the feature of a significantly greater stiffness. No clear-cut diagnostic key is yet available and the clinical usefulness of TUS elastography is currently limited with a view to characterizing tumors. Nevertheless, TUS elastography does allow good noninvasive imaging of lung nodules, providing information on their stiffness, and can improve the safety of FNAB.

Dear Editor,

The brilliant and challenging editorial “Elastography Everywhere – Now Even the Lungs!” is particularly timely and well addressed. It focuses on the fact that clinical ultrasound approaches should be driven by physio-pathology knowledge to reach realistic diagnostic and therapeutic goals. The author, Mostbeck [1], articulates several relevant comments and criticisms in his reappraisal of the study of Adamietz et al. [2], who claim that their preliminary report of a case series dealing with 8 patients with a total of 18 histologically proven metastases of the lung is the first one in the literature and should show the feasibility of real-time elastography (RTE). Moreover, they claim that “in contrast to B-mode sonography, RTE is able to detect and visualize peripheral, non-pleural adherent pulmonary lesions”. We agree with most of the content of Mostbeck’s editorial [1], even if somewhat more could be added, including the fact that there are previous reports of ultrasound (US) elastography of primary lung cancer confirmed by US-guided biopsy. In addition, the statement that “ultrasound (US) and contrast-enhanced ultrasound (CEUS) [3] are currently not commonly used for the detection and visualization of pulmonary nodules” [2] is partially incorrect, in our opinion.

The field of thoracic US (TUS) is very important as the research objects are very prevalent, severe and – hopefully – treatable diseases such as pneumonitis [4], pneumothorax, effusions, fibrosis and autoimmune diseases [5] and lung cancer [6]. For all these entities, the added value of TUS is valuable for reaching an early, tentative preliminary diagnosis. However, even more important is the fact that TUS allows safe interventional guidance of cavity evacuations or of fine-needle aspiration biopsy (FNAB) procedures under the continuous visual US control of the operator [7]. The assessment of lung nodules by state-of-the-art US techniques, including elastography, is not really a completely “exotic” application [1] and, in our opinion, is no longer a pioneering methodology [8].

In 2013, we reported at the American Society of Clinical Oncology (ASCO) meeting a thoracic ultrasound elastography study on lung nodules in 57 proven primary lung cancer patients [9]. The conclusion was not over-enthusiastic: “Only squamous cell lung carcinoma displays the feature of a significantly greater stiffness, no clear-cut diagnostic key is yet available, and the clinical usefulness of TUS elastography is currently limited with a view to characterizing tumors. Nevertheless, TUS elastography does allow good noninvasive imaging of lung nodules, provides some information on their stiffness and on the presence of abscess cavities, and can improve the safety of FNAB also through a more accurate on-site definition of the lesion location which, of course, is finely defined by CT [9]”.

A reappraisal of elastography applications for a better definition of lung nodules primary to US-guided FNAB [10] [11], along with information on CEUS usefulness, which has been previously reported [3], was also included in a recent review [8]. Actually, the possible benefits of using TUS elastography and contrast-enhanced US (CEUS) were not really assumed to better detect lung cancer or to gain information on different histologic cancer subtypes (as cut-off values are not sufficiently established), but to detect the site, position and “quality” (fluid content, vasculature) of lung nodules with more detail, especially when FNAB of these lesions guided by US is considered. The information on “rigidity” is a collateral but, in our opinion, not a determinant detail [12].

There are also other merits of Mostbeck’s editorial [1] since he addresses the need of managing TUS and TUS elastography as imaging procedures complementary to radiology, acknowledging the limitation of TUS, especially the visibility of lung nodules restricted to pleural-based and very subpleural nodules: “Every man takes the limits of his own field of vision for the limits of the world (Arthur Schopenhauer)”. Radiologists and pneumologists are probably more diffident if not skeptical about the merits of TUS because part of the available literature is devoted to studies relying on artifacts, addressing clinical syndromes and decisional trees, in which the relationship with imaging of lung disease is quite remote [13] [14] [15]. The technical difficulties of TUS require adequate and continuous training, particularly if the professional goal is to perform trans-thoracic FNAB with minor trauma and diminished risks for the patient, whenever possible, i. e. when the lesions are sufficiently visible by US. It is noteworthy to remember that in these subsets, and particularly in malignant pleural mesothelioma [7] [8] [16], endo-bronchial ultrasound (EBUS) procedures are less useful and “fruitful”, since more peripheral parts of the lung are not reachable by EBUS. Last but not least, the present hard “caveats” addressed by Mostbeck are welcome since some US aspects of lung imaging by US are unrealistic due to its aerial physical properties.

• References

• 1 Mostbeck G. Elastography Everywhere – Now Even the Lungs!. Ultraschall in Med 2014; 35: 5-8
  Article in Thieme ConnectPubMedGoogle Scholar
• 2 Adamietz BR, Fasching PA, Jud S. et al. Ultrasound Elastography of Pulmonary Lesions – A Feasibility Study. Ultraschall in Med 2014; 35: 33-37
  Article in Thieme ConnectPubMedGoogle Scholar
• 3 Sperandeo M, Sperandeo G, Varriale A. et al. Contrast-enhanced ultrasound (CEUS) for the study of peripheral lung lesions: a preliminary study. Ultrasound Med Biol 2006; 32: 1467-1472
  CrossrefPubMedGoogle Scholar
• 4 Sperandeo M, Carnevale V, Muscarella S. et al. Clinical application of transthoracic ultrasonography in inpatients with pneumonia. Eur J Clin Invest 2011; 41: 1-7
  PubMedGoogle Scholar
• 5 Sperandeo M, Varriale A, Sperandeo G. et al. Transthoracic ultrasound in the evaluation of pulmonary fibrosis: our experience. Ultrasound Med Biol 2009; 35: 723-729
  CrossrefPubMedGoogle Scholar
• 6 Sperandeo M, Filabozzi P, Varriale A. et al. Role of thoracic ultrasound in the assessment of pleural and pulmonary diseases. J Ultrasound 2008; 11: 39-46
  PubMedGoogle Scholar
• 7 Trovato GM, Sperandeo M, Catalano D. Optimization of thoracic US guidance for lung nodule biopsy. Radiology 2014; 270: 308
  CrossrefPubMedGoogle Scholar
• 8 Sperandeo M, Rotondo A, Guglielmi G. et al. Transthoracic ultrasound in the assessment of pleural and pulmonary diseases: use and limitations. Radiol Med 2014; 119: 729
  PubMedGoogle Scholar
• 9 Sperandeo M, Trovato GM, Dimitri L. et al. Ultrasound Elastography Pattern of lung squamous cell carcinoma: Preliminary report on a possible adjunctive tool for noninvasive imaging. J Clin Oncol 2013; 31: e18518
  PubMedGoogle Scholar
• 10 Trovato GM, Sperandeo M, Catalano D. Computed tomography screening for lung cancer. Ann Intern Med 2013; 159: 155
  CrossrefPubMedGoogle Scholar
• 11 Trovato GM, Sperandeo M, Catalano D. Thoracic ultrasound guidance for access to pleural, peritoneal, and pericardial space. Chest 2013; 144: 1735-1736
  PubMedGoogle Scholar
• 12 D'Alessandro V, Parracino T, Stranieri A. et al. Computed-tomographic-guided biopsy of thoracic nodules: a revision of 583 lesions. Clin Ter 2007; 158: 509-513
  PubMedGoogle Scholar
• 13 Trovato GM, Rollo VC, Martines GF. et al. Thoracic ultrasound in the differential diagnosis of severe dyspnea: a reappraisal. Int J Cardiol 2013; 167: 1081-1083
  CrossrefPubMedGoogle Scholar
• 14 Trovato GM, Sperandeo M. Sounds, ultrasounds, and artifacts: which clinical role for lung imaging?. Am J Respir Crit Care Med 2013; 187: 780-781
  CrossrefPubMedGoogle Scholar
• 15 Trovato GM, Catalano D, Martines GF. et al. Is it time to measure lung water by ultrasound?. Intensive Care Med 2013; 39: 1662
  CrossrefPubMedGoogle Scholar
• 16 Heilo A, Stenwig AE, Solheim OP. Malignant pleural mesothelioma: US-guided histologic core-needle biopsy. Radiology 1999; 211: 657-659
  CrossrefPubMedGoogle Scholar
• 17 Mostbeck G. Elastography Everywhere – Now Even the Lungs!. Ultraschall in Med 2014; 35: 5-8
  Article in Thieme ConnectPubMedGoogle Scholar
• 18 Adamietz BR, Fasching PA, Jud S. et al. Ultrasound Elastography of Pulmonary Lesions – A Feasibility Study. Ultraschall in Med 2014; 35: 33-37
  Article in Thieme ConnectPubMedGoogle Scholar
• 19 Sperandeo M, Varriale A, Sperandeo G. et al. Transthoracic ultrasound in the evaluation of pulmonary fibrosis: our experience. Ultrasound Med Biol 2009; 35: 723-729
  CrossrefPubMedGoogle Scholar
• 20 Sperandeo M, Filabozzi P, Varriale A. et al. Role of thoracic ultrasound in the assessment of pleural and pulmonary diseases. J Ultrasound 2008; 11: 39-46
  PubMedGoogle Scholar
• 21 Trovato GM, Sperandeo M, Catalano D. Optimization of thoracic US guidance for lung nodule biopsy. Radiology 2014; 270: 308
  CrossrefPubMedGoogle Scholar
• 22 Linde H-NG, Holland A, Greene BH. et al. Kontrastunterstützte Sonografie (CEUS) bei Pneumonie: Darstellungsmuster und prognostische Bedeutung – eine retrospektive Studie bei n=50 Patienten. Ultraschall in Med 2012; 33: 146-151
  Article in Thieme ConnectPubMedGoogle Scholar
• 23 Kreuter M, Eberhardt R, Wenz H. et al. Diagnostische Wertigkeit der transthorakalen Sonografie vergleichend zur Thoraxübersicht beim Nachweis eines postinterventionellen Pneumothorax. Ultraschall in Med 2011; 32:  E20-E23
  Article in Thieme ConnectPubMedGoogle Scholar
• 24 Piscaglia F, Nolsøe C, Dietrich CF. et al. The EFSUMB Guidelines and Recommendations on the Clinical Practice of Contrast Enhanced Ultrasound (CEUS): Update 2011 on non-hepatic applications. Ultraschall in Med 2012; 33:  33-59
  Article in Thieme ConnectPubMedGoogle Scholar