All of the following are radiolucent kidney stones except-

Ans. is 'd' i.e., Cysteine Urinary stoneso AH individuals with urinary stones should undergo radiological investigation; following radiological modalities are usedPlane abdominal X-ray ("RUB" or kidney - ureter - Bladder X-ray)The first radiological test that is performed is the plain abdominal X-ray. Because majority of stones (90%) are radiopaque, these can be easily identified on X-ray :-Radiolucent stones :- Uric acid stone. Orotic acid stones. Xanthine, Triamterens, Dihydroxy adenine.Radiopaque stones Cystine, Struvite, calcium oxolate, calcium phosphate.Intravenous pyeiogram (IVP)IVP can demonstrate urinary obstruction from renal stone and can demonstrate the position of non - opaque (radiolucent) stones.CT scan:- Non - contrast helical CT is 95 to 100% sensitive and specific for detection of renal calculi and, therefore, is the imagining modality of choice for urinary stones.USG :- USG provide excellent assessments of kidney and bladder but inferior to IVP and CT scan in evaluation of the ureters.