ELASTO ULTRASOUND GUIDELINES: Part 2. CLINICAL APPLICATIONS

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ELASTO GUIDELINES: PART 2. CLINICAL APPLICATIONS

Future perspectives

As befits a new method, elastography is being used in new applications which as yet lack sufficient strength of evidence to justify their inclusion in these Recommendations, though their exclusion should not be taken as implying that they may not prove to be of clinical value once more experience is gained. The topics below are an incomplete list of those that are of clinical interest but whose clinical value is still to be confirmed.

Elastography of superficial lymph nodes, for example in the neck or inguinal regions, is a promising application, where an increase in stiffness would be expected in malignancy but might also occur in inflamed nodes [177, 178].

Intraoperative elastography has been applied to the brain to guide the surgeon to stiffer regions that represent tumours and improve the precision of their resection [179, 180].

Elastography of the uterine cervix to assess the softening that precedes normal dilatation before delivery is potentially important. Premature delivery is a major cause of fetal death, which could be reduced if a simple and reliable means of identifying premature softening could be developed [181].

Testicular tumours are harder than the surrounding gland on palpation and this might be a useful application of elastography to aid the distinction between the commoner malignancies and the rarer less invasive tumours such as Leydig cell tumours, which can be managed with tissue-sparing surgery [182].

Anal incontinence, most commonly an obstetrical injury, leads to scarring which is stiffer than the normal sphincter muscles; a preliminary report focusses on the presurgical findings, with promising results [128] whereas postoperative evaluation was disappointing [183]. Elastography has been used in rectal and anal carcinomas where it improves the discrimination between adenoma and cancer [129] and the differentiation of T2 and T3 stages of rectal cancer. Although this improved differentiation has so far not been evaluated, it seems convincing because inflammatory changes appear softer than the usually harder tumours.

Perineal ultrasound is an effective method for imaging perianal inflammatory lesions (e. g. in Crohn's disease) but is too rarely used. Generally speaking, acute inflammatory lesions are softer and chronic lesions harder in comparison to the surrounding tissue [184].

Arterial and plaque stiffness has been studied in preliminary investigations [135, 185, 186] and might form a clinically useful way to assess vulnerable plaque.

Promising results have been reported on the clinical use of SE for tendon disease such as for common extensor origin tendons in order to depict tendon and fascia involvement in lateral epicondylitis [187], for plantar fascia where stiffness changes with age and disease [188] and for trigger finger, where there is increased stiffness of the flexor tendon which decreases after steroid injections [189]. Preliminary studies also show the potential use of strain elastography in localising myofascial trigger points to inject with botulin toxin [190] and for diagnosing and monitoring of inflammatory myopathies by showing changes in muscle stiffness in correlation with elevated serum markers [173]. Preliminary data are available on stiffness measurements and shear wave velocities of normal muscle and tendon using shear wave techniques [175, 191].

Other applications will no doubt emerge as more experience is gathered.