ABNORMAL SIZE, SHAPE OR POSITION

• Small Kidney
  • Chronic pyelonephritis (ref)
  • Chronic renal failure
  • Chronic obstruction (ref)
  • Congenital hypoplasia
  • Radiation nephritis (ref)
  • Renal artery stenosis
• Absent Kidney
  • Agenesis
  • Nephrectomy
• Large Kidney
  • Acute renal vein thrombosis (ref)
  • Acute renal infarction (ref)
  • Acute pyelonephritis
  • Duplex kidney
  • Polycystic kidneys
• Abnormal Shape
  • Horseshoe kidneys (ref)
• Abnormal Position
  • Pelvic kidney (ref)
  • Ptotic kidney
  • Renal ectopia (ref)
  • Renal transplant

A unilateral small kidney may be seen with chronic pyelonephritis , chronic obstruction, renal artery stenosis, congenital hypoplasia, or radiation nephritis. The absence of a kidney due to agenesis or nephrectomy is easily detected. Unilateral nephromegaly may be present in acute renal vein thrombosis, acute renal infarction, acute pyelonephritis, or a duplex kidney. Uptake in an adjacent mass such as a neuroblastoma, may simulate a large kidney. Renal ectopia, polycystic kidneys and horseshoe kidneys can be recognized on skeletal scintigraphy. Activity in the collecting system of a horseshoe kidney may be confused for abnormal uptake in the lumbar spine . Uptake in a pelvic kidney or in a renal transplant can be confused with abnormal uptake in the iliac bones or sacrum.

Chronic Pyelonephritis

(A) Bone scintigram (posterior view) in a patient with history of chronic pyelonephritis shows a small right kidney. An intravenous pyelogram (B) confirmed the presence of a small scarred right kidney.

Chronic Renal Failure

Bone scintigram (posterior view) in a patient with history of chronic renal failure shows small bilateral kidneys.

Polycystic Kidney

Patient with polycistic kidney, chronic renal failure, and secondary hyperparathyroidism. Bone scan image (A) shows enlarge kidneys with multiple photopenic areas corresponding to multiple cysts on CT (B). Also note lung uptake due to metastatic calcifications as a result of secondary hyperparathyroidism.

Duplicated Collecting System

Skeletal scintigram in posterior projection shows focal accumulation of radiotracer activity in the left collecting system in this patient with duplicated collecting system, that commonly presents with obstruction of the upper collecting system.

Horseshoe Kidney

On a bone scintigram (posterior (A) and lateral (B) images) in a patient with horseshoe kidneys the activity in the collecting system projecting over the spine can be misinterpreted as bone pathology.

Ptotic Kidney

Posterior (A) and right anterior oblique (B) views of a whole-body bone scintigram shows that the right kidney is displaced inferiorly a large liver mass. Patient has hepatoma.

Pelvic Kidney

(A) Bone scintigram in anterior projection shows absence of the right kidney in its usual location and collection of activity projecting over the lumbar spine and sacrum, a finding that corresponds to a pelvic right kidney seen on intravenous pyelogram (B).

Renal Transplant

Bone scintigram in anterior view (A) shows asymmetrically increased radionuclide activity in the region of the left iliac fossa, that on an oblique projection (B) represents an extraossoeus structure. Patient had undergone prior renal transplantation.