Most sensitive test for ureteric stones is?

ANSWER: (B) Non contrast CT scanREF: Blueprints radiology - Alina Uzelac, Ryan W. Davis Page 151, Essential urology: a guide to clinical practice: Volume 1 - Jeannette M. Potts Page 97, American Family Physician. 2001 Apr 1; 63(7): 1329-1339."Where available, a non-contrast helical CT scan with 5 millimeters (0.20 in) sections is the diagnostic modality of choice in the radiographic evaluation of suspected nephrolithiasis. All stones are detectable on CT scans except very rare stones composed of certain drug residues in the urine, such as from indinavir"Imaging Modalities in the Diagnosis of Ureteral CalculiImaging modalitySensitivity(%)Specificity(%)AdvantagesLimitationsU Itrasonography1997Accessible, Good for diagnosing hydronephrosis and renal stones, Requires no ionizing radiationPoor visualization of ureteral stonesPlain radiography45 to 5971 to 77Accessible and inexpensiveStones in middle section of ureter, phleboiiths, radiolucent calculi, extraurinary calcifications and non- genitourinary conditionsIntravenouspyelography64 to 8792 to 94Accessible, Provides information on anatomy and functioning of both kidneysVariable-quality imaging, Requires bowel preparation and use of contrast media, Poor visualization of non- genitourinary conditions, Delayed images required in high-grade obstructionNoncontrast helical computed tomography95 to 10094 to 96Most sensitive and specific radiologic test (i.e., facilitates fast, definitive diagnosis) Indirect signs of the degree of obstruction, Provides information on n on-genitourinary conditionsLess accessible and relatively expensive, No direct measure of renal functionTreatment Modalities for Renal and Ureteral CalculiTreatmentIndicationsAdvantagesLimitationsComplicationsExtracorporeal shock wave lithotripsyRadiolucent calculi, Renal stones < 2 cm, Ureteral stones <1 cmMinimallyinvasiveOutpatientprocedureRequires spontaneous passage of fragments, Less effective in patients with morbid obesity or hard stonesUreteral obstruction by stone fragments, Perinephric hematomaUreteroscopyUreteral stonesDefinitiveOutpatientprocedureInvasive, Commonly requires postoperative ureteral stentUreteral stricture or injuryU reterorenoscopyRenal stones < 2 cmDefinitiveOutpatientprocedureMay be difficult to clear fragments, Commonly requires postoperative ureteral stentUreteral stricture or injuryPercutaneousnephrolithotomyRenal stones > 2 cm Proximal ureteral stones > 1 cmDefinitiveInvasiveBleeding Injury to collecting system. Injury to adjacent structures Patient with abdominal pain |History and physical anamination| Renal colic suspected|Diagnostic Imaging||| Patient Is pregnant, or cholecystitis or gynecologic ocess 5 suspectedPatient has hrsaxy of radcoeque calculiAlt ether patterns| ||||UltrasoundexaminabonPlain-filmradiographyIntravenous pyelography if CT is not availableNoncontrast helical CT u | ||||StonedetectedStone not detects? ||Stone detectedStone not detected| || Clintcsl suspicion of urolithiasis --