ULTRASOUND DIAGNOSTICS OF LUNG TUMOR INVASION OF THE CHEST WALL: PITFAILS AND DIFFICULTIES

Purpose: One of the main methods of treatment in lung cancer, the most common malignant tumor in the world, is surgical operation. One of the causes of lung carcinoma inoperability lies in tumor penetration to the chest wall. Chest sonography is the best method for diagnostics in such situation. The aim of the investigation was to define pitfails and difficulties while ultrasound diagnosing lung tumor invasion (TI) in chest wall.

Methods and Materials: Ultrasound examinations (US) of the chest wall and lungs were performed in 88 patients with peripheral lung tumor using 3–5MHz convex or sector probes and 7,5MHz linear probes. Operations were carried out in 45(51,1%) cases.

Results: Next signs were used for diagnostics of TI of the chest wall: 1). Tumor immobility during respiration and/or cough; 2). Tumor penetration into soft tissues of the chest wall; 3) Destruction of ribs and their substitution by tumor. Involvement of the chest wall was determined, if no less than one sign was found. TI of the chest wall was diagnosed in 35(39,8%) cases including 18(40%) of operated patients. US allowed to diagnose chest wall affection in 13(28,9%) of operated patients, in one case false-positive conclusion was done. Marked adhesive process in pleural cavity was the reason of this mistake. False-negative conclusion in one case was given because of localization of TI in costovertebral region: mobility of ribs about the tumor was seen. Infiltration of soft tissues was invisible because of acoustic shadow behind ribs and vertebral column. Lobar atelectasis in patients with centralization of peripheral tumor was the reason of mistakes in the rest four cases: it wasn_t possible to examine tumor mobility during respiration. Central tumor was supposed until the operation in all of these cases. The sensitivity, specificity and accuracy of US in diagnosis of TI of the chest wall were 72,2%, 96,2% and 86,7%. In 41 operated patients without massive atelectasis the same indices were 92,9%, 96,2% and 95,1%.

Conclusions: As a whole, next pitfails and difficulties in diagnostics of TI of the chest may be classify: 1). Adhesive process in pleural cavity. False-positive conclusion may be done because of immobility of lung tumor. 2). Local TI of the chest wall. Rotatory movement of the tumor around commit point (place of invasion) may be seen instead of parallel movement of the tumor about the chest wall. False-negative conclusion may be done in such case. 3). TI in costovertebral region. Mobility of ribs about the tumor may be seen while infiltration of chest wall is invisible because of acoustic shadow from bones. If TI is extensive, movement of the tumor about the chest wall is parallel. If TI is local, we can see rotatory movement of the tumor, but the point of invasion is invisible: it is closed by bones. False-negative conclusions may be done in such cases. 4). TI in area of apex of lung. False-positive conclusion may be done because of depressed mobility of lung surface (and, therefore, noninvasive tumor) according to standard in this area. 5). Massive atelectasis in cases of peripheral tumor with centralization. False-negative conclusion may be done: we can not see tumor mobility. Diagnostics is possible, if the tumor invading into soft tissues and ribs only.