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Difficulty: HardOrdering Imaging Studies

A 64-year-old man comes to the clinic reporting an episode of painless, bright red urine this morning. He denies any flank pain, abdominal discomfort, dysuria, fever, or increased urinary frequency. His medical history is significant for hypertension, hyperlipidemia, and a 45-pack-year smoking history. Current medications include hydrochlorothiazide and atorvastatin. He has no known drug allergies. Vital signs are within normal limits. Physical examination, including abdominal palpation and a digital rectal examination, is unremarkable.

Laboratory results:
Serum creatinine: 0.9 mg/dL

Urinalysis:
Color: Red
Clarity: Cloudy
Specific gravity: 1.018
Blood: Large
Protein: Negative
Leukocyte esterase: Negative
Nitrites: Negative
WBC: 1-2/hpf
RBC: >50/hpf

In addition to cystoscopy, which of the following is the most appropriate next step in the diagnostic imaging evaluation of this patient?

  1. Computed tomography (CT) urographyAnswer
  2. B
    Non-contrast computed tomography (CT) of the abdomen and pelvis
  3. C
    Renal and bladder ultrasonography
  4. D
    Magnetic resonance (MR) urography
  5. E
    Positron emission tomography (PET) scan

Answer

Computed tomography (CT) urography
The correct answer is Computed tomography (CT) urography. This patient's presentation of painless macroscopic hematuria, combined with advanced age and a significant smoking history, strongly suggests a urologic malignancy until proven otherwise. A complete evaluation requires cystoscopy (to assess the bladder and urethra) and upper urinary tract imaging (to assess the kidneys and ureters). CT urography is the gold standard imaging modality for this purpose. It utilizes a multiphasic protocol that includes a non-contrast phase (to detect radiopaque stones), a nephrographic phase with intravenous contrast (to evaluate the renal parenchyma for solid masses like renal cell carcinoma), and an excretory phase (to evaluate the urothelium of the renal pelvis and ureters for filling defects caused by transitional cell carcinoma). Because the patient has normal renal function, there is no contraindication to utilizing iodinated contrast.

Step-by-Step Solution

1
Analyze the patient's clinical presentation and demographic risk factors.
The patient is an older male with a 45-pack-year smoking history presenting with painless, macroscopic (gross) hematuria.
Identifying these classic red flags establishes a high pretest probability for a urologic malignancy, particularly urothelial (transitional cell) carcinoma or renal cell carcinoma.
2
Review the initial laboratory data.
Urinalysis confirms gross hematuria (>50 RBCs/hpf) without signs of infection (negative nitrites and leukocyte esterase). Serum creatinine is normal (0.9 mg/dL).
This rules out a simple urinary tract infection as the cause of bleeding and confirms normal renal function, meaning the patient can safely clear iodinated intravenous contrast.
3
Determine the required diagnostic workup based on established guidelines for painless gross hematuria.
The standard of care requires direct visualization of the lower urinary tract (cystoscopy) combined with comprehensive cross-sectional imaging of the upper urinary tract.
Urothelial carcinoma can occur anywhere from the renal pelvis down to the bladder. Cystoscopy evaluates the bladder, while upper tract imaging evaluates the kidneys and ureters.
4
Select the optimal imaging modality for the upper urinary tract.
Computed tomography (CT) urography is selected as the most appropriate study.
CT urography is a multiphasic scan (non-contrast, nephrographic, and excretory phases) that provides the highest sensitivity and specificity for detecting both solid renal masses and urothelial irregularities.

Key Concept

In patients with painless macroscopic hematuria and risk factors for malignancy (e.g., older age, smoking history), the gold standard imaging evaluation for the upper urinary tract is CT urography, which must be paired with cystoscopy for lower tract evaluation.
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Topics

Ordering Imaging Studies

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