It's a cool, sunny morning here in San Francisco, and the Stanford MDCT conference continues with Session V, looking at hepatobiliary and genitourinary imaging with CT. Knowing what urologists need and expect from their colleagues in radiology is particularly important as imaging continues to disseminate into other subspecialties, which is why I enjoyed Dr. Elliot Fishman's examination of the pitfalls of MDCT imaging of renal masses.
Fishman noted that "there's no one single phase that will visualize all the lesions" in the kidney, emphasizing the importance of both the non-contrast and subsequent phases -- particularly the excretory phase. "If you only had one phase of acquisition, that's the one you'd want," he said. He added that multiplanar data is important to urologists, especially coronal views. "This is what they expect from us," he told the audience.
More information on the oh-so-crucial excretory phase was provided by Graham Sommer, MD, who walked us through the Stanford protocol for MDCT urography. At Stanforf, the excretory phase is optimized by having the patient drink a liter of water 15-20 minutes before the study begins. Sommer noted that an informal survey of radiologists recently indicated that 33% do nothing to maximize this phase -- no IV saline, no diuretics and no hydration.
"I'm surprised to see that nothing is a preferred alternative to oral hydration," he said. He went on to get a few laughs out of the crowd -- no easy feat in the somber, quiet Grand Ballroom -- by adding, "After all, water is cheap, it's rarely contraindicated and so far we've observed very few side effects."
Dushyant Sahani, MD, presented on urolithiasis -- more commonly known as kidney stones, one of the most common reasons to visit a urologist in the first place. Sahani noted that the lifetime risk of getting a kidney stone is around 15%, and recurrence within a decade is common. "Imaging has demonstrated a very important tole in establishing an accurate diagnosis," he noted.
As a kidney stone sufferer myself, I was intrigued to hear that a high-tech method of diagnosis is needed. To me, the crippling pain has always had both the sensitivity and the specificity necessary for accurate diagnosis. What I didn't know is that MDCT can provide valuable information on stone size, fragility, and composition, helping determine what type of treatment will be best.
"We have historically done well with CT, but the expectations have changed," Sahani said. "Now we also need to know about stone composition. This is very important to determining stone management."