Salvador Miralles MD, Presenter: Nothing to Disclose

Jose Vizuete, Abstract Co-Author: Nothing to Disclose

Tomas Ripolles MD, Abstract Co-Author: Nothing to Disclose

Maria Jesus Martinez Perez, Abstract Co-Author: Nothing to Disclose

Fructuoso Delgado MD, Abstract Co-Author: Nothing to Disclose

Teresa Pastor, Abstract Co-Author: Nothing to Disclose

To assess the usefulness of twinkling artifact in abdominal ultrasound studies in patients with renal colic.

From October 2008 to September 2009 we studied 109 patients with renal colic. The studies were done by 4 radiologists with different levels of experience (a 2 nd year resident, a 4th year resident and two staff radiologists with more than 10 years of experience). US examination was routinely initialized with the evaluation, of the kidney, proximal ureter and vesiocureteral union (the areas most accessible by ultrasound) and then with B-mode color Doppler. In cases where lithiasis was not visualized in these two areas the entire ureters were assessed with color Doppler. A CT scan without IV contrast was performed in cases where no lithiasis was visualized on ultrasound. All patients were followed clinically.  

We confirmed the presence of ureteral lithiasis in 94/109 (86%) patients, with clinical (spontaneous expulsion of the calculus), other imaging techniques (IVU or CT) or with interventional radiology techniques or lithotripsy. The ultrasound detected 85 lithiasis (sensitivity 90%, specificity 100%). The combination of lithiasis over obstructive signs showed a sensitivity of 97% and a specificity of 93%. The twinkling artifact was visualized in 64 (76%) lithiasis; in 41 cases it was seen before calculi, and in 4 cases the artifact was seen without identifying the lithiasis. The average duration of the ultrasound examination was 5.8 ± 4.3 minutes (range: 1-20 minutes). Although it was initially suspected renal colic, some patients had different diagnoses such as diverticulitis, ovarian torsion, liver metastases with retroperitoneal lymph nodes, bladder tumor, retrocaval ureter, cystitis, and acute pyelonephritis.  

Ultrasound can be used as an initial technique in patients with suspected ureteral lithiasis. The use of color Doppler twinkling artifact display increases the sensitivity of ultrasound and shortens the time of exploration. Ureteral calculi may be difficult to detect if acoustic shadowing is not seen or when intestinal gas or mesenteric fat are adjacent to the ureter. The twinkling artifact may be of great help in these cases.  

Twinkling artifact in abdominal US studies, allows a faster evaluation and an appropiate location of calculi in the urinary tract which can be important in making decisions quickly and appropiatrely.

Miralles, S, Vizuete, J, Ripolles, T, Martinez Perez, M, Delgado, F, Pastor, T, Usefulness of Twinkling Artifact for Detecting Ureteral Lithiasis in Patients with Renal Colic.  Radiological Society of North America 2011 Scientific Assembly and Annual Meeting, November 26 - December 2, 2011 ,Chicago IL. http://archive.rsna.org/2011/11010363.html