Digital tomosynthesis—a new lease of life for the intravenous urogram?

Abstract

Objectives: Digital tomosynthesis is a new digital technique based on conventional Xray tomography. It acquires multiple low-dose projections during a single sweep of the X-ray tube, which are reassembled to provide high-resolution slices at different depths. Suggested uses include visualisation of pulmonary nodules, mammography, angiography, dental imaging and delineation of fractures. This study aims to evaluate its potential role as part of an intravenous urogram (IVU) by assessing the diagnostic quality in imaging the kidneys in clinical practice. Methods: 100 renal units from consecutive traditional IVU studies were retrospectively compared with 101 renal units imaged using digital tomosynthesis. These were scored for visualisation of the renal outline and collecting system, presence of a renal cyst or mass and overall diagnostic quality. Radiation doses were calculated. Results: 46.5% of traditional IVUs were found to be of diagnostic quality. The IVUs with digital tomosynthesis were of diagnostic quality in 95.5%. This represents a highly statistically significant difference (p,0.0001). There was also a statistically significant dose reduction, with a mean reduction of 56%, for the samples studied. Conclusion: Digital tomosynthesis offers a significant increase in the percentage of diagnostic quality tests for assessing renal pathology, compared with traditional IVU, and significantly reduces radiation. It also offers considerable advantages in ease and speed of imaging. For these reasons, in any situation where IVU is still being used to assess the kidneys, digital tomosynthesis is likely to be of considerable benefit in improving diagnostic quality.

The value of X‑ray digital tomosynthesis in the diagnosis of urinary calculi

“…However, it administers a high dose of radiation to patients and follow-up is expensive, thus limiting its application. Previous studies determined that the conventional and low effective doses of UMDCT are higher than those of DTS (4,(8)(9)(10). In the present study it was determined that the detection rate of DTS prior to bowel preparation was 94.2%.…”

“…The Kidneys-Ureters-Bladder (KUB) radiograph is able to effectively identify the location of calculi (3). However, due to the influence of intestinal gas and the overlapping area of the abdominal cavity, KUB radiography has certain disadvantages, including low-density resolution, low sensitivity and low accuracy (4). Unenhanced multidetector computed tomography (UMDCT) is the procedure of choice for the radiological evaluation of patients with renal colic (5).…”

Imaging for urolithiasis

“…Sensitivity was 64 and 76% for stones between 2 and 5 mm and those larger than 5 mm, respectively. The radiation dose of digital tomosynthesis was only slightly increased in comparison to digital radiography and was substantially lower than CT or even low-dose CT. A second study by Wells et al compared the diagnostic quality of IVP with digital tomosynthesis to conventional IVP [57]. The addition of digital tomosynthesis to conventional IVP increased the diagnostic quality from 46.5 to 95.5% with a mean radiation dose reduction of 56%.…”

Radiation Exposure in the Follow-Up of Patients with Urolithiasis Comparing Digital Tomosynthesis, Non-Contrast CT, Standard KUB, and IVU

“…9 Wells et al studied the diagnostic quality of an IVU performed with the technique of DT. 10 In their study, two uro-radiologists compared a traditional IVU with an IVU performed with DT. They found that 95.5% of the IVU with DT were of subjective diagnostic quality v 46.5% of the traditional IVUs.…”