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Thứ Bảy, 30 tháng 6, 2012

AJR 7-2012

1.        Performance of Real-Time Strain Elastography, Transient Elastography, and Aspartate-to-Platelet Ratio Index in the Assessment of Fibrosis in Chronic Hepatitis C

OBJECTIVE. The purpose of this article is to evaluate the diagnostic performance of transient elastography, real-time strain elastography, and aspartate-to-platelet ratio index in assessing fibrosis in patients with chronic hepatitis C by using histologic Metavir scores as reference standard.

SUBJECTS AND METHODS. Consecutive patients with chronic hepatitis C scheduled for liver biopsy were enrolled. Liver biopsy was performed on the same day as transient elastography and real-time strain elastography. Transient elastography and real-time strain elastography were performed in the same patient encounter by a single investigator using a medical device based on elastometry and an ultrasound machine, respectively. Diagnostic performance was assessed by using receiver operating characteristic curves and area under the receiver operating characteristic curve (AUC) analysis.

RESULTS. One hundred thirty patients (91 men and 39 women) were analyzed. The cutoff values for transient elastography, real-time strain elastography, and aspartate-to-platelet ratio index were 6.9 kPa, 1.82, and 0.37, respectively, for fibrosis score of 2 or higher; 7.3 kPa, 1.86, and 0.70, respectively, for fibrosis score of 3 or higher; and 9.3 kPa, 2.33, and 0.70, respectively, for fibrosis score of 4. AUC values of transient elastography, real-time strain elastography, aspartate-to-platelet ratio index were 0.88, 0.74, and 0.86, respectively, for fibrosis score of 2 or higher; 0.95, 0.80, and 0.89, respectively, for fibrosis score of 3 or higher; and 0.97, 0.80, and 0.84, respectively, for fibrosis score of 4. A combination of the three methods, when two of three were in agreement, showed AUC curves of 0.93, 0.95, and 0.95 for fibrosis scores of 2 or higher, 3 or higher, and 4, respectively.

CONCLUSION. Transient elastography, real-time strain elastography, and aspartate-to-platelet ratio index values were correlated with histologic stages of fibrosis. Transient elastography offered excellent diagnostic performance in assessing severe fibrosis and cirrhosis. Real-time elastography does not yet have the potential to substitute for transient elastography in the assessment of liver fibrosis.

o        © American Roentgen Ray Society

2. Snapping Knee: Imaging Findings With an Emphasis on Dynamic Sonography


Snaps usually result from the sudden displacement of an anatomic or pathologic structure during the movement of a neighboring joint.

Depending on the patient, repeated snaps may be regarded with mild curiosity or experienced with significant discomfort or true pain, compelling sufferers to reduce sports or professional activities. Identifying the structure responsible for the snap may be clinically challenging because of the depth at which the snap occurs and the fact that multiple causes are possible in the same area of a given joint.

Radiographs and CT scans are efficient in depicting bony structures. Additionally, MRI has good contrast resolution for soft-tissue components. Nevertheless, both techniques are usually performed in a static way that lacks time-frame resolution and prevents proper identification of transient snapping phenomena. In recent years, real-time sonography has proved to be an efficient approach, not only in the depiction of musculoskeletal snaps but also in the understanding of their underlying pathophysiology. Sonography emerges as the only technique with true dynamic capabilities that can provide an accurate correlation between symptoms and the movement of a suspected structure. In some cases, dynamic sonography may, nevertheless, be challenged by the depth of occurrence of a snap or the inability of the patient to reproduce it on demand at the time of scanning. Operator experience is another obvious factor contributing to a successful examination.

Because of its large size and the numerous anatomic structures that may be cartilaginous, fatty, and fibrous, the knee joint hosts a wide range of snapping conditions. Compared with the great number of articles that deal with pain or gross instability associated with cruciate ligament tears or patellar instability, few clinical studies including more than one patient have focused on the presence of a snap as an isolated cause of knee discomfort.

In native and prosthetic knee joints, both intra- and extraarticular structures can cause a snap. Most of these conditions are accessible to dynamic sonography.


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