Imaging US: — Echogenic with twinkle artifact more common than posterior acoustic shadowing on newest US machines due to spatial compounding — US blind spot is mid ureter — Presence of ureteral jets on US does not exclude stones — Can show dilated collecting system — US has moderate sensitivity for detecting stones and false negatives are common
Imaging CT without contrast: — Very sensitive for detecting stones — Stone protocol CT can be performed in prone position to distinguish bladder stones from stones lodged at ureterovesical junction
Imaging CT with contrast: — Obstruction due to stones causes delayed nephrogram — Pararenal stranding — Collecting system dilation
DDX: Artificial collagen injection mounds can calcify mimicking stones at the ureterovesical junction
Complications: Stones cause obstruction at ureteropelvic junction and mid ureter and ureterovesical junction (most common)
Treatment: Lithotripsy
Clinical: — Increasing in incidence in children — Types are calcium oxalate 70-80%, calcium phosphate 5-10%, struvite 5-10%, uric acid 5-10%, cysteine 1-5%
Radiology Cases of Nephrolithiasis
Radiology Cases of Kidney Stones
Axial CT without contrast of the abdomen (above left) shows a hydronephrotic left kidney with a small amount of perinephric fat stranding. There is a high density calcification associated with the inferior aspect of the left kidney (below left) that on the sagittal image (right) is seen to be at the left of the ureteropelvic junction.
Radiology Cases of Ureteral Stones
Axial (left) and coronal (right) CT without contrast of the abdomen shows a dense calcification at the right ureteovesical junction. There is mild associated enlargement of the right kidney with mild inflammatory fat stranding around the right kidney.
Radiology Cases of Bladder Stones
AXR AP (above) shows two irregularly-shaped calcified objects projecting over the pelvis. Spinal dysraphism is noted in the sacrum. There is a cecostomy tube in the right lower quadrant. Sagittal US of the bladder (below) shows an echogenic mass within the inferior aspect of the bladder (to the right of the image) that has posterior shadowing.Transverse (above) and sagittal (below) US of the bladder shows a round echogenic mass in the base of the bladder that has posterior shadowing. The bladder wall is mildly thickened.
Radiology Cases of Bladder Stones and Urethral Foreign Body
Transverse US of the prostatic urethra (upper left) shows a small round echogenic lesion with posterior shadowing in the center of the prostatic urethra which was not seen in the transverse US of the penile urethra (upper right). Sagittal US of the bladder (lower left) shows an echogenic lesion with posterior shadowing in the posterior aspect of the bladder that on transverse US of the bladder (lower right) resolved into two separate echogenic lesions with posterior shadowing.
