1. 1. Presentor: Dr Kusum Pathania Moderator: Dr Jyoti Arora IMAGING OF ADRENAL MASSES
2. 2. Adrenal Gland The adrenal gland is named for its location adjacent to the kidneys: ad-renal Also known as suprarenal glands Characteristic inverted Y, V, or T shape Pair of important endocrine glands situated on the posterior abdominal wall over the upper pole of the kidneys behind the peritoneum. Each gland is enclosed in the perirenal fascia and each have a body and two limbs -medial and lateral.
3. 3. HISTOLOGY ADRENAL CORTEX-90% of adrenal three zones 1.Zona glomerulosa-outer most 10-15% Secretes mineralocorticoids (aldosterone) 2.Zona fasciculata-80% - secretes cortisol 3.Zona reticulata-5-10% - secretes androgens
4. 4. ADRENAL MEDULLA- 10% of adrenal made up of chromaffin cells, secretes-EPINEPHRINE or NOREPINEPHRINE Partof sympathetic autonomic nervous system.
5. 5. VASCULAR SUPPLY: Arterial supply : inferior phrenic artery superiorly. aorta medially . renal artery inferiorlly Venous drainage : Right side: drain to IVC . Left side : drain to left adrenal vein or directly to IVC. Lymphatics : Para-aortic and paracaval lymph nodes.
6. 6. Normal gland CT Right adrenal gland : superior to right kidney, medial to right lobe of liver, lateral to crus of right hemidiaphragm, posterior to IVC. Shape : elongated comma lying in crease between liver and crus of diaphragm.
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8. 8. Normal gland CT Left adrenal gland : superior to and anterior to upper pole of kidney in triangle formed by left lateral margin of aorta, posterior surface of body and tail of pancreas and upper pole of left kidney.
9. 9. Normal CT measurements: Length - 4-6cm Width -2-3cm . Each limb normally measures 5mm in width and the body should measure 8-10mm in width Criteria for Enlargement: Length >6cm AP diameter > 3cm Limb thickness > 6mm Thickness more than adjacent crus.
10. 10. PURPOSE : Overview of adrenal disease and their imaging appearance. Current concept of differentiating a benign from malignant adrenal mass with particular attention to CT and MRI. Present an imaging alogrithm for characterizing an adrenal mass.
11. 11. IMAGING MODALITIES : Ultrasound Computed tomography Magnetic resonance imaging Nuclear medicine imaging
12. 12. ULTRASOUND : Primarily reserved for use in pediatric population because of lack of ionising radiation and small body habitus of children. Right adrenal best evaluated from midaxillary and anterior axillary line . Liver provide acoustic window. Left adrenal evaluated from posterior or mid axillary approach. No suitable acoustic window for left so completely evaluated in 80% of people.
13. 13. CT Routine CT protocol for adrenal imaging NCCT abdomen CECT abdomen (70 secs delay) Delayed scan (after 15 minutes) Computed tomography (CT) is the imaging modality of choice for evaluating adrenal glands morphology and masses associated with it. High resolution CT of upper abdomen, using 1-3mm thick slices to reduce the volume averaging, is most accurate technique for indentifying adrenal lesions. Contrast-enhanced CT and delayed images help in further characterization of the lesions. 100-150ml of contrast is injected at a rate of 3mlper second and images are aquired at 70sec and 15 min after contrast injection.
14. 14. MRI MRI of the adrenals is the modality of choice for further characterization of adrenal lesions. MR parameters should include T1-and T2-weighted sequences along with chemical shift imaging. T1 weighted signal show normal adrenal as low signal against high signal fat. Most tumor show high signal on T2W and low signal on T1W image. Contrast enhanced dynamic MRI used in d/d of adenoma, metastasis, granulomas and pheochromocytoma Chemical shift MR used in d/d of adenoma and metastasis: adenoma high lipid content
15. 15. (a)T1-weighted breath-hold. MR image demonstrates a normal left adrenal gland (arrow). (b)T2 weighted MR image. Normal gland MRI
16. 16. NUCLEAR MEDICINE IMAGING FDG PET. I-131MIBG In-111Octreotide
17. 17. Adrenal masses A. Neoplasm B. Other mass lesion 1. Cortical 1. Granuloma a. adenoma a. tuberculosis b. carcinoma b. histoplasmosis 2. Medullary c. blastomycosis a. pheochromocytoma 2. Bilateral hyperplasia b. neuroblastoma 3. Cyst c. ganglioneuroma a. endothelial (45%) 3. Stromal b pseudocyst (39%) a. lipoma c. epithelial (9%) b. myelolipoma d. parasitic (hydatid) 4. Metastasis 4. Hematoma
18. 18. ADRENAL DISEASES GROUP I : Adrenal disease with normal function. GROUP II : Adrenal Hyper-functional disease. GROUP III: Adrenal insufficiency.
19. 19. GROUP I : ADRENAL DISEASE WITH NORMAL FUNCTION: Most of these are incidentally detected as adrenal masses. Include : nonfunctional adrenal adenoma or carcinoma, metastasis , lymphoma , myelolipoma , adrenal cyst.
20. 20. INCIDENTALLY DISCOVERED ADRENAL MASSES: Common incidental discoveries on CT, MRI, FDG- PET. Adrenal incidentaloma lesions 20 HU) Enhancement with contrast Delayed contrast washout (10 min) Absolute contrast washout < 60% Isointensity or slightly less intense than liver T-1 , high to intermediate intensity T-2 MRI (represent water increase)
21. 61. Left adrenal metastases in a 74-year-old man with lung cancer. (a) T1- weighted in-phase MR image demonstrates a left adrenal mass (arrow). (b) T1-weighted out-of-phase MR image shows no significant signal loss in the adrenal gland compared with that of the spleen. The mass is either a metastasis or atypical adenoma, and biopsy was recommended.
22. 62. MYELOLIPOMA: Benign tumor of the cortex comprised of both mature fat and hematopoeitic cells. AGE=5Th to 6Th decade SEX=M=F C/F----asymptomatic/mass effect Imaging appearance may vary acc to histological component.
23. 63. USG----- 1.SIZE---- capillary AGE50-70yrs SEXF:M=2:1 C/Fasymptomatic
24. 97. Most characteristic are phleboliths and presence of vascular lakes. Centripetal enhancement is less characteristic than in hepatic hemangioma
25. 98. Imaging findings X-raycalcifications (64%)---similar to phleboliths USG no-specific app, heterogenous lesion often large>10cm is seen.
26. 99. NCCT----well- delienated hypoattenuating heterogenous mass + necrotic areas CECT----periph. pools of contrast (vasc. lakes) fill- in phenomenon less freq.- necrosis/hge/ fibrosis
27. 100. MRI---- T-1-heter. Low signal, periph. persistent enhancement in delayed images. T-2-high signal.
28. 101. Conclusion Most adrenal masses are incidentalomas and amongst them, adenomas are most common, which can be functioning or non- functioning. Some adrenal masses may have pathognomonic CT features such as myelolipoma, cysts, lipid-rich adenomas and malignant masses but most incidentalomas have nonspecific morphologic features. Most adrenal adenomas are lipid-rich and can be correctly diagnosed on chemical-shift MR imaging or unenhanced CT. Most lipid-poor adenomas can be accurately characterized on delayed enhanced CT. In patients with a primary extraadrenal neoplasm and no other evidence of distant metastatic disease, noninvasive imaging can reduce the necessity for percutaneous adrenal mass biopsy in most patients by confirming presence of adenoma. Percutaneous biopsy can be limited to larger masses whose imaging studies are not specific & do not indicate an adenoma.