CHAPTER 32
ALL ABOUT URO
ADRENAL GLANDS
- MDCT
- modality of choice
- Inverted V of Y shaped
- Limbs - 4 to 5 cm in length and 5 to 7 mm in thickness
- Chemical shift MR. Used to demonstrate intracellular fat. In benign adrenal adenoma by
utilizing in phase and out phase gradient recalled sequences. Intracellular fat demonstrate
signal loss on OP images - lipid rich adenoma
INCIDENTAL ADRENAL MASS
- < 4cm adrenal nodules are benign non hyper functioning adrenal cortical adenoma
Adrenal cortical adenoma
- MC adrenal mass and increasing in incidence with age
- 70% lipid rich adenoma, 30% lipid poor adenoma
- attenuation of adenoma on unenhanced image is -20 to 30 HU
- benign adenoma - characterized by rapid wash out of the contrast agent
Adrenal metastases
- < if less than 4 cm cannot be distinguished from benign
- > 4cm features of malignancy including inhomogeneous density, irregular shape, thick
irregular margination, internal hemorrhage or necrosis and invasion of adjacent structures
- Stability over time - absence of change for 6 months - benign
- increase size over 6 months is a strong evidence of malignancy
- Measurements of attenuation below 10 e ectively excludes malignancy
Perfusion di erences between adenoma and metastasis
- Rapid washout of contrast agent for adenoma whereas metastasis show slow contrast
washout
Delayed attenuation di erences are made on
images at 10 to 15 minutes following the onset of
intravenous contrast
-2 to 16 HU - lipid rich adenoma and higher HU of
20 - 25 are seen in lipid poor adenoma.
Adenoma typically demonstrate rapid washout
which is de ned as an APW if more than 60% and
40% RPW criteria used on either 10-15 minute
delayed images
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, MR characterization depends on chemical shift techniques that detect intracellular lipid. MR
o ers no-capability to characterize lipid poor adenomas. Repeat study with contrast CT or
PET-CT should be done.
Lesions not categorized by these methods may do follow up imaging in 4-6 months or for
image guided biopsy. Caution if it is likely to be pheochromocytoma - may precipitate
hypertensive crisis.
ADRENAL ENDOCRINE SYNDROMES
Cushing syndrome
- excessive amount of cortisone and corticosterone
- adrenal hyperplasia
- MR of sella may be done for suspected pituitary adenoma
Conn syndrome
- elevated level of aldosterone
- Hypertension, hypokalemia and urine aldosterone
- A solitary benign hyperfunctioning adrenal cortical adenoma is the cause of 80%
- Adrenal hyperplasia is the cause in 2%
Adrenogenital syndrome
- occurs in newborns and infants who have 11B or 22 hydroxylase de ciency leading to
production of aldosterone and cortisol and excess precursors of androgens
- adenomas and carcinomas
Addison disease
- primary adrenal insu ciency- occurs if adenal cortex is destroyed
- Idiopathic atrophy which is probably autoimmune
- other causes tuberculosis, histoplasmosis, infarction, lymphoma
- Bilateral enlargement seen in active infection
- Calci cation - tuberculosis or histoplasmosis
Pheochromocytoma
- hypertension, headace and tremors
- Rules of 10. 10 percent are bilateral, extra adrenal, are malignant, familial and incidental
- Associated with MEN II, von Hippel Lindau and neuro bromatosis
- cal i cation is rare but usually eggshell in con guration when present
- Washes out slowly like malignant lesions
- No change in IP and OP images
- Radionuclide scans using I-metaiodobenzylguanide (MIBG) are e ective in localizing
BENIGN ADRENAL LESIONS
Adrenal hyperplasia
- cause of 70% cases of cushing and 2% in Conn
- Must be distinguished from adenoma. Treated medically whereas adenoma is surgical
removal
- May appear normal. Uncommonly ,may appear nodular and mimic solitary or multiple
adenoma
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, - In di use hyperplasia, the limbs are longer than 5 cm and exceed 10 mm thickness
Adrenal myelolipoma
- no malignant potential
- Range in size up to 30 cm and are frequently inhomogeneous because of theri mixed
components of marrow fat and hemopoietic tissue
- Large lesions >5 cm have atendency to hemorrhage
- Calci cations are present in 20%
Adrenal hemorrhage
- MC in newborn infants
- Hypoxia, birth trauma or septicemina
- Most are bilateral
- In children - associated with child abuse
- Unilateral - MC in adults, right mc
- Additional ndings - fat stranding and thickening
Adrenal calci cation
- MC as a result from adrenal hemorrhage
- Tuberculosis and histoplasmosis may also calcify
Adrenal Cysts
- rare, produce no symptoms
- < 3 mm thin walls and size do not exceed 5 o 6 cm in size
Ganglioneuroma
- rare benign tumor
MALIGNANT ADRENAL LESIONS
Adrenal carcinoma
- Most are large > 6 cm and invasive at presentation
- Cause endocrine syndrome - mostly Cushing syndrome wih central areas of necrosis and
hemorrhage showing irregular enhancement
- Wash out us delayed in post contrast images
- Calci cation is present, hepatic and lymph node mets are common
- Tumor thrombus in renal vein may be evident
Lymphoma
- rare
KIDNEYS
IMAGING METHODS
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ALL ABOUT URO
ADRENAL GLANDS
- MDCT
- modality of choice
- Inverted V of Y shaped
- Limbs - 4 to 5 cm in length and 5 to 7 mm in thickness
- Chemical shift MR. Used to demonstrate intracellular fat. In benign adrenal adenoma by
utilizing in phase and out phase gradient recalled sequences. Intracellular fat demonstrate
signal loss on OP images - lipid rich adenoma
INCIDENTAL ADRENAL MASS
- < 4cm adrenal nodules are benign non hyper functioning adrenal cortical adenoma
Adrenal cortical adenoma
- MC adrenal mass and increasing in incidence with age
- 70% lipid rich adenoma, 30% lipid poor adenoma
- attenuation of adenoma on unenhanced image is -20 to 30 HU
- benign adenoma - characterized by rapid wash out of the contrast agent
Adrenal metastases
- < if less than 4 cm cannot be distinguished from benign
- > 4cm features of malignancy including inhomogeneous density, irregular shape, thick
irregular margination, internal hemorrhage or necrosis and invasion of adjacent structures
- Stability over time - absence of change for 6 months - benign
- increase size over 6 months is a strong evidence of malignancy
- Measurements of attenuation below 10 e ectively excludes malignancy
Perfusion di erences between adenoma and metastasis
- Rapid washout of contrast agent for adenoma whereas metastasis show slow contrast
washout
Delayed attenuation di erences are made on
images at 10 to 15 minutes following the onset of
intravenous contrast
-2 to 16 HU - lipid rich adenoma and higher HU of
20 - 25 are seen in lipid poor adenoma.
Adenoma typically demonstrate rapid washout
which is de ned as an APW if more than 60% and
40% RPW criteria used on either 10-15 minute
delayed images
fiff ff ff
, MR characterization depends on chemical shift techniques that detect intracellular lipid. MR
o ers no-capability to characterize lipid poor adenomas. Repeat study with contrast CT or
PET-CT should be done.
Lesions not categorized by these methods may do follow up imaging in 4-6 months or for
image guided biopsy. Caution if it is likely to be pheochromocytoma - may precipitate
hypertensive crisis.
ADRENAL ENDOCRINE SYNDROMES
Cushing syndrome
- excessive amount of cortisone and corticosterone
- adrenal hyperplasia
- MR of sella may be done for suspected pituitary adenoma
Conn syndrome
- elevated level of aldosterone
- Hypertension, hypokalemia and urine aldosterone
- A solitary benign hyperfunctioning adrenal cortical adenoma is the cause of 80%
- Adrenal hyperplasia is the cause in 2%
Adrenogenital syndrome
- occurs in newborns and infants who have 11B or 22 hydroxylase de ciency leading to
production of aldosterone and cortisol and excess precursors of androgens
- adenomas and carcinomas
Addison disease
- primary adrenal insu ciency- occurs if adenal cortex is destroyed
- Idiopathic atrophy which is probably autoimmune
- other causes tuberculosis, histoplasmosis, infarction, lymphoma
- Bilateral enlargement seen in active infection
- Calci cation - tuberculosis or histoplasmosis
Pheochromocytoma
- hypertension, headace and tremors
- Rules of 10. 10 percent are bilateral, extra adrenal, are malignant, familial and incidental
- Associated with MEN II, von Hippel Lindau and neuro bromatosis
- cal i cation is rare but usually eggshell in con guration when present
- Washes out slowly like malignant lesions
- No change in IP and OP images
- Radionuclide scans using I-metaiodobenzylguanide (MIBG) are e ective in localizing
BENIGN ADRENAL LESIONS
Adrenal hyperplasia
- cause of 70% cases of cushing and 2% in Conn
- Must be distinguished from adenoma. Treated medically whereas adenoma is surgical
removal
- May appear normal. Uncommonly ,may appear nodular and mimic solitary or multiple
adenoma
ff fi fifi ffi fi fi ff fi
, - In di use hyperplasia, the limbs are longer than 5 cm and exceed 10 mm thickness
Adrenal myelolipoma
- no malignant potential
- Range in size up to 30 cm and are frequently inhomogeneous because of theri mixed
components of marrow fat and hemopoietic tissue
- Large lesions >5 cm have atendency to hemorrhage
- Calci cations are present in 20%
Adrenal hemorrhage
- MC in newborn infants
- Hypoxia, birth trauma or septicemina
- Most are bilateral
- In children - associated with child abuse
- Unilateral - MC in adults, right mc
- Additional ndings - fat stranding and thickening
Adrenal calci cation
- MC as a result from adrenal hemorrhage
- Tuberculosis and histoplasmosis may also calcify
Adrenal Cysts
- rare, produce no symptoms
- < 3 mm thin walls and size do not exceed 5 o 6 cm in size
Ganglioneuroma
- rare benign tumor
MALIGNANT ADRENAL LESIONS
Adrenal carcinoma
- Most are large > 6 cm and invasive at presentation
- Cause endocrine syndrome - mostly Cushing syndrome wih central areas of necrosis and
hemorrhage showing irregular enhancement
- Wash out us delayed in post contrast images
- Calci cation is present, hepatic and lymph node mets are common
- Tumor thrombus in renal vein may be evident
Lymphoma
- rare
KIDNEYS
IMAGING METHODS
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