Objective: The aim of our study was to determine if virtual unenhanced CT (VUCT) is equivalent to unenhanced CT (UCT) for detecting urinary stones. Methods: Our institutional review board approved this retrospective study, which was compliant with the Health Insurance Portability and Accountability Act. A total of 80 stones were detected in 32 patients among 146 consecutive patients undergoing dualenergy CT urography. The number and size of stones were recorded on nephrographic VUCT (NVUCT) and excretory VUCT (EVUCT) images, respectively. UCT was a reference of standard for the number and size of stones. Image quality of VUCT was qualitatively assessed using a five-point scale. Repeated-measures analysis of variance with post-test was used for statistical analysis. Results: 62 stones in 29 patients were detected on NVUCT and 59 stones in 27 patients were detected on EVUCT. The size of stones detected on NVUCT or EVUCT was significantly smaller compared with stones on UCT (p,0.05). The size of stones detected on UCT, NVUCT and EVUCT ranged from 1.4 to 19.2 mm (mean, 4.6 mm), 0 to 19.2 mm (mean, 3.6 mm) and 0 to 18.7 mm (mean, 3.6 mm), respectively. 18 stones were missed on NVUCT and 21 were missed on EVUCT. The sizes ranged from 1.4 to 3.2 mm (mean, 2.1 mm) and 1.4 to 3.2 mm (mean, 2.2 mm) on UCT, respectively. VUCT was inferior to UCT regarding image quality (p,0.05). Conclusion: VUCT missed a significant number of small stones probably owing to poor image quality compared with UCT. Subsequently, VUCT cannot replace UCT for detecting urinary stones. Urolithiasis is a common cause of haematuria. Unenhanced CT (UCT) is considered a gold standard for diagnosing this disease entity because it is more sensitive to detecting urinary stones than simple radiography and ultrasound [1][2][3]. Therefore, UCT is an essential CT protocol that should be included for CT urography. Dual-energy CT (DECT) imaging can reconstruct virtual unenhanced CT (VUCT) images from contrastenhanced CT images. As VUCT is equivalent to UCT in characterising renal masses, radiation dose to patients can be reduced during CT scans using dual-energy sources [4,5]. DECT is also useful in evaluating composition of urinary stones, uric acid stones can be differentiated from calcified stones [6][7][8][9][10]. However, there are few in vitro or in vivo reports about the validity of VUCT in detecting urinary stones [11][12][13]. Still, it is unclear whether or not VUCT can be an alternative imaging to UCT for diagnosing urolithiasis.The purpose of our study was to determine whether or not VUCT is equivalent to UCT in detecting urinary stones. Methods and materialsThis retrospective study was approved by our institutional review board and informed consent was waived. PatientsBetween September 2009 and March 2010, a total of 146 patients (male-to-female ratio, 73:73; age range, 23-87 years; mean age 56 years) underwent CT urography due to one of the following chief complaints: microscopic haematuria (n560), gross haematuria (n525), flank discomfort (n546) ...

Objectives: To evaluate the incidence and pattern of spinous process fractures (SPFs) in patients with osteoporotic compression fractures (OCFs) of the thoracolumbar spine. Methods: Spinal MRI or CT of 398 female patients (age range 50-89 years, mean age 70 years) who had OCFs in the thoracolumbar spine were retrospectively reviewed. The incidence, location and imaging results for the SPFs were evaluated. Results: Of the 398 patients who had thoracolumbar OCFs, 14 (3.5%) had SPF. In six patients with single compression fractures, the SPF occurred at the level just above the vertebral compression fracture. In six out of seven patients with multiple continuous compression fractures, the SPF occurred just one level above the uppermost level of the compression fracture. The remaining one patient who had thoracolumbar spinal fixation at T12-L2 with continuous compression fractures in T12-L5 had a SPF in L2. In one patient who had multiple compression fractures in discontinuous levels (fractures at T10 and L1, respectively), the SPF occurred at T12. The directions of the fractures were vertical or oblique vertical (perpendicular to the long axis of the spinous process) in all cases. Conclusion: In the presence of an OCF in the thoracolumbar spine, a SPF was found in 3.5% of cases, and most of the fractures were located just one level above the compression fracture. Therefore, in patients who have OCF, the possibility of a SPF in the level just above the compression fracture should be considered. Osteoporosis is a common disease owing to an increase in the population of older people. Osteoporosis is a disease that induces bone fragility, caused by a decrease in trabecular bone, and the resulting fracture is called an insufficiency fracture. The most common osteoporotic compression fractures occur in the spine, sacrum, pubis, femoral neck and wrist [1].Although the most common methods for imaging vertebral fractures are still spinal radiographs, benign spinal compression fractures are commonly detected by MRI or CT on osteoporotic patients with back pain. Sometimes, it is difficult to differentiate a benign spinal compression fracture from a malignant cause of the spinal compression fracture. However, in most cases, a benign spinal compression fracture shows some specific features: a low-signal-intensity band on T 1 and T 2 weighted images, spared normal bone marrow signal intensity of the vertebral body, retropulsion of a posterior bone fragment and multiple compression fractures [2]. A relationship between osteoporosis and benign spinal compression fractures, including insufficiency fractures, has been reported. A study examining the relationship between benign compression fractures of the spine and insufficiency fractures of the sacrum has also been reported [3]. However, there have been few reports of spinous process fractures in the osteoporotic spine [4]. Moreover, there have been no studies examining the relationship between spinous process fractures and benign compression fractures of the spine.We have noted ind...