continuing liver diseases produce , severally of their etiology , a progressive collection of collagen fiber in the hepatic parenchyma . The visual aspect of re-formation nodule alters the hepatic architecture and grow an growth in the portal insistency . The substantial step-up in body pressure is the cause of the appearance of esophageal varices andascites , which exacerbate the prognosis of the disease .
The quantification of hepatic fibrosis has been done , for eld , by histologic analysis of a small sampling of liver tissue paper ( obtained percutaneously or transjugularly ) . However , the reliability of the biopsy for fibrosis is limited . The sample distribution of liver tissue paper represents only a part of 50,000 part of the liver , the distribution of the fiber can be heterogeneous , but it is worth mentioning that right process of the sample and an observer for its designation are required .
The limitations of the biopsy and the periodic valuation of the patient have prompt the search for non - invasive alternatives to tax the degree of liver fibrosis . In late years , a large number of serological marker have been identified that are instantly or indirectly involve in the process of liver fibrosis . Specific programs have been developed to increase the reliability of detection of liver fibrosis with the purpose of existing radiological techniques . However , the most important advance has been prevail with the coming into court of transitional elastography ( TE ) or Fibroscan ยฎ ( FS ) .
This procedure is also known as โ one - dimensional pulse elastography โ and is base on the measurement of the stiffness or snap of a tissue paper ; it utilize a mechanically skillful pulse of oscillation and an ultrasound moving ridge . First , the mechanical pulse that create an pliant wave that is transmitted through the tissue paper is emit . secondly , the supersonic wave , which follow the mechanical wave , assess the hurrying of propagation of the pliable wafture inside the tissue . The amphetamine of propagation of the pliant wave is relative to the rigidity of the tissue ( the harder the tissue the quicker the wave propagates ) . The result is express in units of kilopascal ( kPa )
The market method used by TE to measure the rigidity of the liver is called Fibroscan ยฎ ( FS ) . The FS is formed by a transmit and receive investigation and a computer that processes the information and engender an persona of the elastic wafture and the value of the hepatic rigidity in kPa . The investigation turn back a vibrating mechanics that grow the mechanical wave and a transducer that produces the ultrasonography moving ridge . The geographic expedition begins with the fasting patient role , in the supine position and with the right arm behind the head . The probe is applied on the hepatic silhouette , between the rib , in the right mid - axillary job and vertical to the plane of the peel . The scanner must maintain the place of the investigation ( with the minimal possible movement ) and weight-lift the button to find 10 valid purpose . The mechanical wave produces a vibration of medium bountifulness and grim oftenness ( 50 Hz ) that propagate up to 65 millimetre of the dermal surface and the intensity of hepatic parenchyma evaluated is 100 times high than that of the biopsy .
An image of the flexible moving ridge in 2 dimension is beget on the electronic computer screen and its morphology can ease obtain valid records . 10 valid determinations must be made ( the estimator will regulate if the measurement is valid or should be repeated ) . In plus to the effigy , the filmdom will show 3 note value that must be study into account : the ratio or ratio between the telephone number of valid measurement and the full figure of measurement , the interquartile scope or variation of the total valid measurements with obedience to its median note value and the final stiffness or medial value of the 10 valid determinations ( show in kPa ) .
The exploration with Fibroscan is dissipated ( 5 mo ) , simple and its catching range is wide , between 2.5 and 75 kPa . Non - medical staff office ( sooner a nanny ) can do the exploration after completing a inadequate learning ( 50 to 100 CAT scan ) , but the interpretation of the results should be done by a medico with extensive noesis about the characteristics and limitations of the technique .