MATERIALS AND METHODS: This study was approved by the institutional review board and informed consent was waived. Between January 2007 and January 2011, the clinical data and imaging studies of 28 patients older than 18 years diagnosed with renal anomaly at the authors' institution were retrospectively reviewed. Renal anomalies in this study included only those with abnormality in position and in form.

RESULTS: Of these 28 patients, 22 underwent imaging studies and their results constituted the material of this study. Of the 22 patients, 14 had horseshoe kidneys (HSK), four had crossed renal ectopia and four had malrotation. Sixteen patients were men and six were women. The patients ranged in age from 19 to 74 years (mean age 51.1 years). Clinical presentations were abdominal pain (13), fever (13), haematuria (4), palpable mass (2), asymptomatic (2), polyuria (1) dysuria (1), blurred vision (1), and headache with weakness of left extremities (1). Imaging studies included abdominal radiograph (15), intravenous pyelography (IVP) (8), retrograde pyelography (RP) (4), ultrasonography (US) (7), and computed tomography (CT) (9). Associated complications included urinary tract stones (17), urinary tract infection (16), hydronephrosis (12), and tumours (2). Abdominal radiograph suggested renal anomalies in nine out of 15 studies. IVP, RP, US and CT suggested anomalies in all patients who had these studies performed. However, CT was the best imaging modality to evaluate anatomy, function and complications of patients with renal anomalies.

METHODS: Twenty-one patients with LA and 21 age-matched controls were studied with CTP and assessed for their cognitive function. The subjects were classified into four groups: Group 1, with LA (n = 21); Group 2, without LA (n = 21); Group 3, with dementia (n = 7); Group 4, without dementia (n = 11). The mean cerebral blood flow (CBF), cerebral blood volume (CBV) and mean transit time (MTT) values were compared between groups 1 and 2, while mean CBF values were compared between groups 3 and 4.

RESULTS: Mean white matter CBF was considerably reduced in patients with LA in the frontal region by 42% (p = 0.000), basal ganglia by 37% (p = 0.000) and occipital region by 18% (p = 0.019). The mean white matter CBV was reduced in patients with LA in the frontal region by 36% (p = 0.000) and basal ganglia by 28% (p = 0.017). The mean white matter CBF was dramatically reduced in patients with dementia in the frontal region by 44% (p = 0.000), basal ganglia by 32% (p = 0.038) and occipital regions by 24% (p = 0.001).

MATERIALS AND METHOD: Automatic registration was performed on kVCBCT studies of the head and pelvis of a RANDO anthropomorphic phantom. Images were reconstructed with 1.0 ≤ Δτ (mm) ≤ 5.0 at 1.0 mm increments. The phantoms were offset by a known amount, and the suggested shifts were compared to the known shifts by calculating the residual error. A uniform cylindrical phantom with cylindrical inserts of various known CT numbers was scanned with kVCBCT at 1.0 ≤ Δτ (mm) ≤ 5.0 at increments of 0.5 mm. The contrast-to-noise ratios for the inserts were measured at each Δτ.

RESULTS: For the planning CT slice thickness used in this study, there was no significant difference in residual error below a threshold equal to the planning CT slice thickness. For Δτ > 3.0 mm, residual error increased for both the head and pelvis phantom studies. The contrast-to-noise ratio is proportional to slice thickness until Δτ = 2.5 mm. Beyond this point, the contrast-to-noise ratio was not affected by Δτ.