You will be given a definition of a task first, then some input of the task.
Given a passage with a context and an answer, construct a question on the basis of the information present in the passage. Construct the question in such a way that (i) it is unambiguous, (ii) it is answerable from the passage, (iii) its answer is unique (iv) it answer uses text phrases from the passage. Avoid creating questions that (i) can't be answered correctly without actually understanding the passage and (ii) uses the same words or phrases given in the passage.

Context: Renal ultrasound is very important in the diagnosis of renal tumors.', 'From January 2000 to Jannuary 2005 we retrospectively examined the records of 116 patients, 37 women and 79 men (mean age 54 years, range 22-77), who underwent radical nephrectomy for kidney cancer in clinical stage CT1N0M0. 2.5 cm was the tumor dimension limit between the nephron sparing surgical technique and radical nephrectomy. We subdivided the sample into 2 groups, the first of 45 patients with tumor lesions smaller than 2.5 cm and the second with tumor lesions between 2.5 cm and 7 cm in diameter all patients underwent preoperative staging including ultrasound scan (ETG) and computer tomography scan (CT).', 'Ultrasound has showed 35% sensitivity and 49% specificity for lesions under 2.5 cm in diameter, and 65% sensitivity and 75% specificity and 80% specificity for lesions under 2.5 and 80% sensitivity and 95% specificity for lesions between 2.5 and 7 cm.
Answer: Ultrasound is the first step in the staging of renal cancer before surgery; to assess. 2.5 and 7 in diameter CT scan is the gold standard for solid and cystic lesions.
Output:
Do detection rate of ultrasound vs CT scan in clinical staging accuracy of renal tumors pT1NxMx?