*Chapter 32 - Adrenal Glands and Kidneys (CHERI NOTES) Flashcards
In patients WITHOUT a known malignancy; most small (<4 cm) adrenal nodules are _____________. (p.796)
BENIGN HYPERFUNCTIONING ADRENAL CORTICAL ADENOMAS
Most common adrenal mass found in 4% to 6 % of the population increasing in incidence with age. (p.797)
ADRENAL CORTICAL ADENOMAS
Attenuation of ADENOMAS on unenhanced CT has a range of ____. (p. 797)
RANGE OF -20 TO 30 HU
Benign adenomas are characterized on MDCT by _____. (p. 797)
RAPID WASHOUT OF THE CONTRAST AGENT
Most common primary tumors with adrenal metastases. Name six of them. (p. 797)
- LUNG 2. BREAST 3. MELANOMA 4. GASTROINTESTINAL 5. THYROID 6. ADRENAL
Small adrenal metastases (< __ cm) tend to be homogeneous; well defined and difficult to distinguish from benign; nonfunctioning adenomas (p. 797)
< 4 cm
On CT and MR; larger adrenal metastases (> 4 cm); generally shows features characteristic of malignancy; including _______. Name FIVE of them. (p.797)
- INHOMEGENEOUS DENSITY 2. IRREGULAR SHAPE 3. THICK IRREGULAR MARGINATION 4. INTERNAL HEMORRHAGE OR NECROSIS 5. INVASION OF ADJACENT STRUCTURES
A well recognized feature of benign adenoma (p.797)
STABILITY OVER TIME - absence of change in size and appearance of a small adrenal lesion for 6 months is generally accepted as evidence of BENIGNANCY. - increase in size of the lesion over 6 months is strong evidence of MALIGNANCY.
Patients with hypertension should be evaluated for _____ and _____ (p. 797).
CUSHING and CONN syndromes - Cushing Syndrome is excluded with the absence of HYPERTENSION and OBESITY.
Imaging modality for ADRENAL METASTASES (p.797)
MULTIDETECTOR CT (MDCT)
Non-Contrast CT diagnostic feature of a benign lipid-rich adenoma (70% of patients). CT ATTENUATION? (p.798)
CT ATTENUATION OF LESS THAN 10 H - measurement is made on a thin section through the center of the lesion - range-of-interest(ROI) cursor should cover at least half of the lesion surface; avoiding areas of necrosis or hemorrhage
ADENOMAS are characterized by ____ washout of the contrast agent; ADRENAL METASTASES shows _____ contrast washout (p.798).
RAPID; SLOW
Percentage washout measurements are made on images taken at ________ (p. 798).
60 TO 75 SECONDS FOLLOWING THE ONSET OF INTRAVENOUS CONTRAST INJECTION (ENHANCED ATTENUATION)
DELAYED ATTENUATION MEASUREMENTS are made on images obtained at _____. (p. 798)
10 or 15 minutes following contrast injection
BENIGN ADRENAL LESIONS show ______ absolute percentage washout (APW) and __________ relative percentage washout at 15 minutes (p.798 to 799).
GREATER THAN 60 % (APW); GREATER THAN 40% (RPW)
Chemical shift MR relies on the ______ (p.799)
DIFFERENT PRECESSION FREQUENCIES OF FAT PROTONS VERSUS WATER PROTONS - when fat and water molecules occupy the same voxel; the MR signal from fat and water tend to cancel out each other reducing the signal intensity - CHEMICAL SHIFT MR consists of IP sequences when fat and water signals are additive and OP sequences when fat and water signals are subtractive.
A reduction in signal intensity on OP images as compared to IP images is indicative of _____. (p. 799)
INTRACELLULAR FAT - when evaluating adrenal nodules; the chemical shift MR finding of signal drop indicates a BENIGN LIPID-RICH ADENOMA
Patients with adrenal lesions not characterized by chemical shift MR should be considered for ________ (p. 799)
REPEAT STUDY WITH CONTRAST-ENHANCED CT or PET CT
PET-CT shows high sensitivity in the detection of malignant lesions because of _______ accumulate FDG (p.799-800)
HIGH METABOLIC ACTIVITY
Hemorrhage or necrosis within a metastasis may cause falsely ____ FDG uptake (p.800)
falsely NEGATIVE
Some metastases are false-negative on PET; including those from __ and ___ (p. 800)
NEUROENDOCRINE TUMORS and BRONCHIOALVEOLAR LUNG CA
Some benign lesions include ___ ; ___ and ___ lesions may show slightly increased acitivty in PET-CT (p.800)
- OCCASIONAL ADENOMAS 2. INFECTIOUS 3. INFLAMMATORY
Lesions smaller than __ cm are NOT accurately evaluated by PET (p.800)
1 cm
Adrenal lesions that show more FDG uptake than the liver parenchyma; SUV max greater than 3.1 . BENIGN OR MALIGNANT? (P.800)
MALIGNANT -lesions not categorized by the aforementioned PET-CT methods are considered for follow-up imaging in 4-6 months or for image-guided biopsy
CT-guided adrenal biopsy may be performed using _____ approach or with ____ positioning with adrenal lesions side _____ to diminish the risk of pneumothorax (p. 800)
TRANSHEPATIC approach; DECUBITUS positioning; side DOWN - adrenal biopsy is generally avoided if the lesion Iikely to be a PHEOCHROMOCYTOMA (may precipitate a hypertensive crisis)
______ syndrome is caused by excessive amounts of hydrocortisone and corticosterone released by the adrenal cortex (p. 800)
CUSHING syndrome