Table 2.
Differential diagnosis table of renal cystic disease
| Renal cystic disease | Imaging modality | Imaging findings |
|---|---|---|
| Lithium nephropathy | X-ray/IVP | None |
| Ultrasound | Normal sized kidneys with increased echogenicity | |
| CT | Normal sized kidneys with numerous small hypodense cysts | |
| MRI-T1 | Hypointense small cysts not differentiated from renal parenchyma [6] | |
| MRI-T2 | Numerous 1–2 mm hyperintense cysts [6] | |
| Contrast enhancement | Renal parenchyma enhances while cysts are hypointense and do not enhance [6] | |
| Simple renal cysts | X-ray/IVP | None |
| Ultrasound | Thin-walled anechoic cysts with well-defined posterior walls and posterior acoustic enhancement [7] | |
| CT | Multiple and bilateral sharply marginated variable sized cysts measuring −10 to +20 Hounsfield units [8] | |
| MRI-T1 | Variable sized hypointense cysts | |
| MRI-T2 | Variable sized hyperintense cysts | |
| Contrast enhancement | None | |
| Autosomal dominant polycystic kidney disease (ADPKD) | X-ray/IVP | Enlarged renal shadow with filling defects bilaterally. |
| Ultrasound | Bilateral progressive nephromegaly with multiple, variable sized, well-defined anechoic cysts within cortex and medulla [7] | |
| CT | Progressive nephromegaly with parenchymal replacement by numerous variable sized hypodense cysts [8] Hemorrhage may cause calcification and increased attenuation | |
| MRI-T1 | Nephromegaly with cysts of variable size and signal intensity [6] | |
| MRI-T2 | Nephromegaly with cysts of variable size and signal intensity [6] | |
| Contrast enhancement | Parenchymal enhancement without cyst enhancement | |
| Glomerulocystic kidney disease | ||
| X-ray/IVP | None | |
| Ultrasound | Bilateral renal enlargement with cortical and medullary echogenicity with multiple small cortical cysts and loss of corticomedullary differentiation [10] | |
| CT | Multiple small hypodense cysts at the corticomedullary junction [10] | |
| MRI-T1 | Hypointense cortex with loss of the corticomedullary junction [10] | |
| MRI-T2 | Small hyperintense cortical cysts and normal medulla [6] | |
| Contrast enhancement | None | |
| Medullary cystic kidney disease | ||
| X-ray/IVP | None | |
| Ultrasound | Cortical thinning with well-defined, anechoic cysts involving medulla and corticomedullary region [9] | |
| CT | Thinned cortex with hypodense cysts involving medulla and corticomedullary region [9] | |
| MRI-T1 | Thinned cortex with hypointense to intermediate medullary and corticomedullary cysts [9] | |
| MRI-T2 | Thinned cortex with hyperintense medullary and corticomedullary cysts [9] | |
| Contrast enhancement | None | |
| Acquired cystic kidney disease | ||
| X-ray/IVP | None | |
| Ultrasound | Small echogenic kidneys with variable sized, well-defined anechoic cysts [9] | |
| CT | Small kidneys with replacement of parenchyma with numerous hypodense cysts variable in size [6] | |
| MRI-T1 | Small kidneys with cortical and medullary cysts of variable size and signal intensity | |
| MRI-T2 | Small kidneys with cortical and medullary cysts of variable size and signal intensity | |
| Contrast enhancement | None |