logging in or signing up adrenal imaging ppt drvivektewari Download Post to : URL : Related Presentations : Share Add to Flag Embed Email Send to Blogs and Networks Add to Channel Uploaded from authorPOINT lite Insert YouTube videos in PowerPont slides with aS Desktop Copy embed code: (To copy code, click on the text box) Embed: URL: Thumbnail: WordPress Embed Customize Embed The presentation is successfully added In Your Favorites. Views: 543 Category: Entertainment License: All Rights Reserved Like it (7) Dislike it (0) Added: December 20, 2010 This Presentation is Public Favorites: 0 Presentation Description Radiological Imaging of Adrenal Gland Comments Posting comment... By: myoushani (1 month(s) ago) so many thanks for this great lecture may i download it thanks Saving..... Post Reply Close Saving..... Edit Comment Close By: khudur (12 month(s) ago) great presentation . would you please give me the permission to download it . thank you Saving..... Post Reply Close Saving..... Edit Comment Close By: yasmineg (14 month(s) ago) how can i download plz? Saving..... Post Reply Close Saving..... Edit Comment Close By: hoangtubui (14 month(s) ago) How can i download this file? Saving..... Post Reply Close Saving..... Edit Comment Close Premium member Presentation Transcript Adrenal imaging : Adrenal imaging Introduction : Introduction Among most important and vital endocrine organ Small bilateral yellowish retroperitoneal organ Lies just above kidney in gerota’s fascia 2 Anatomy : Anatomy 3 Right adrenal is triangular, related to upper pole Right kidney Left adrenal is crescent shaped, related to upper and medial part Left kidney Average size is 3-5 cm long, 2-3 cm wide and 5 mm in thickness Average weight is 3-5 g of which 90 % is contributed by cortex. Most frequent shapes of the adrenals : Most frequent shapes of the adrenals Embryology : Embryology 5 Cortex is mesodermal in origin Week 4 – 6 : start from coelomic mesoderm adjacent to urogenital ridge Week 8 : differentiate into thin definite outer cortex and thick inner fetal cortex Cont: : Cont: 6 Fetal cortex produce steroid during gestation and involutes at birth Definite cortex develop into functional adrenal cortex Embryology : Embryology 7 Medulla derived from neural crest cells Develop with sympathetic nervous system Week 5 : neural crest cell migrate to Para-aortic and Para-vertebral region towards medial aspect of adrenal cortex Cont: : Cont: 8 Extra adrenal chromaffin cells located to the left of aortic bifurcation near the origin of IMA Embryology : Embryology 9 Embryology : Embryology 10 Embryology : Embryology 11 Embryology : Embryology 12 Physiology : Physiology Adrenal gland has two distinct zones Adrenal cortex Adrenal medulla 13 Physiology : Physiology 14 Adrenal cortex produces -Glucocorticoids (Zona Fasciculata) -Mineralocorticoids (Zona Glomerulosa) -Adrenal androgens (Zona Reticularis) Physiology : Physiology 15 Adrenal medulla produces -Epinephrine (adrenaline) -Norepinehrine (noradrenaline) Help inc in cardiac output, vascular resistance and mediate stress response All are absolutely required for life Functions : Functions 16 Aldosterone helps in Na reabsorption & potassium excretion & preventing dehydration Cortisol stimulate protein breakdown, inhibition of tissue response in injury & antagonism to action of insulin Androgens helps in early development of male sex organ in childhood Functions : Functions 17 Slide 18: 18 Relations : Relations RT ADRENAL Anteriorly IVC Liver Posteriorly Diaphragm LT ADRENAL Anteriorly Pancreas Stomach Posteriorly Diaphragm 19 Relations : Relations Vascular supply : Vascular supply 21 Blood to adrenal supplied by Inferior phrenic artery (superiorly) Aorta (medially) Renal artery (inferiorly) Vascular supply : Vascular supply 22 Right Adrenal : drained to IVC via adrenal vein Left Adrenal : drained into left adrenal vein or directly to IVC Lymphatics : drained to Para-aortic and para-caval lymph nodes IMAGING INVESTIGATION : IMAGING INVESTIGATION Plain Radiography Intravenous urography Retroperitoneal air insufflation Arteriography Phlebography Inferior vena cavagraphy Hormone assay Ultrasound CT scanning MRI Needle biopsy Plain Radigraphy : Plain Radigraphy Mass Masses smaller than 5 cm are not visualised Seen displacing the kidney Calcifications Idiopathic Neoplasm Granuloma Cyst Old haemorrhage Wolmans disease Incidental adrenal lesion (IAL) : Almost all incidental adrenal lesions(IALs) in patients without a known primary cancer are benign. Characterization of IALs in cancer patients predict prognosis to assess staging to direct therapy Almost all IALs are characterized by using imaging alone, although some lesions require percutaneous biopsy for definitive characterization. Characterization depends on lesion morphology perfusion differences between benign and malignant masses the intracellular lipid concentration of the mass and the metabolic activity of the mass CT contrast medium washout tests offer the highest test sensitivity and specificity for IAL characterization Incidental adrenal lesion (IAL) CT Scan-Incidental adrenal lesion (IAL) : CT Scan-Incidental adrenal lesion (IAL) Primary imaging tool Targeted scan-adrenal only or non targeted scan - the entire abdomen Slice thickness -2.5 mm Contrast enhanced scans 100-150 ml at rate of 3 ml per second . between 25 and 40 seconds for arterial or parenchymal phase at 70 seconds after contrast injection for routine portovenous phase Delayed imaging done at 10 or 15 min CT SCAN : CT SCAN Lesion Size A definitive size threshold cannot be used to confidently distinguish benign from malignant lesions with diameter as the only imaging finding The appropriateness criteria of the American College of Radiology emphasize that management with respect to lesion size depends on whether patients have a history of malignancy; in those who do not, benign-appearing tumors smaller than 3 cm likely are benign Excision is generally advised for incidentally discovered masses larger than 5 cm Morphological appearance IAL : Morphological appearance IAL Adrenal size : Adrenal size Precontrast Attenuation : Precontrast Attenuation Lee et al explained the importance of centering the ROI within the lesion to avoid partial volume effects and beam-hardening artifacts, which are most pronounced in the periphery. In their 1998 review, Boland et al described the circular ROI and indicated that the circle must be large enough to cover at least one half of the cross-sectional area of the mass. Precontrast attenuation : Precontrast attenuation Precontrast attenuation : Precontrast attenuation Many investigators use a cutoff of less than 10 HU to diagnose an adenoma, a technique supported by the American College of Radiology appropriateness criteria Adenomas with higher pre contrast attenuation may identified by performing delayed contrast material– enhanced CT to measure washout characteristics Percentage washout formulas : Percentage washout formulas Percentage washout : Percentage washout Percentage washout : Percentage washout Histogram Analysis : Histogram Analysis MRI : MRI Single most important imaging protocol –chemical shift imaging Chemical shift imaging is performed with in-phase and opposed phase T1 weighted GRE technique. A coronal T2 weighted image without fat suppression Axial T2 weighted image with fat suppression If adrenal mass is not found to be adenoma on chemical shift imaging – Pre and post GAD gradient echo imaging with fat suppression Chemical shift imaging : Chemical shift imaging Adrenal venous sampling : Adrenal venous sampling Each adrenal vein catheterized via transfemoral or transjugular route Bilateral adrenal vein samples are tested for aldosterone in an attempt to localise the functional tumor to one gland Performed under continuous infusion of ACTH which acutely stimulates aldosterone Cortisol is measured to prove that the samples are taken from the adrenal vein Adrenal venous sampling : Adrenal venous sampling Ultrasound : Ultrasound Primarily reserved for use in pediatric population Right adrenal completely imaged in 90 % Left adrenal imaged in 80 % Visualised from the mid-axillary, anterior axillary, posterior axillary and sub costal oblique approach Structures mistaken to be adrenals Diaphragmatic crus Gastric diverticulum Renal or retroperitoneal masses Accessory spleen Ultrasound in evaluating adrenals : Ultrasound in evaluating adrenals In some cases the adrenal glands can be easily identified without localising the mains vessels. However, in most cases, especially if the adrenal glands are normal or small, the vessels will be needed to identify the location of the adrenal glands. Right adrenal gland : Right adrenal gland Left adrenal gland : Left adrenal gland Nuclear Medicine Imaging : Nuclear Medicine Imaging Usual role of scintigraphy is a second line test to clarify equivocal, inconclusive or unexpected results from anatomical imaging Indications Demonstrate functional status of adrenal nodules Assess function in contralateral gland To confirm bilateral disease in pituitary driven syndromes Detect extra adrenal or ectopic sites of hormone production To detect functioning metastasis in patients with primary adrenal tumors To detect recurrence after surgery Radionuclide imaging : Radionuclide imaging Adrenal cortex- Labeled cholesterol analogues given IV are incorporated into low density lipoproteins and concentrated into adrenal cortex where they join the synthetic pathway for steroid production These tracers undergo esterification but are then stored in the intracellular lipid pool Only a small portion reaches the adrenals remaining excreted in the bile Rate of clearance and excretion of the tracer is slow a long lived radionuclide is needed Most effective is 75 Se – labeled seleno-nor-cholesterol (t1/2 is 120 days) Adrenal cortex radionuclide imaging : Adrenal cortex radionuclide imaging Images are acquired 5 days and again 7 days after the injection Additional 99TC DMSA is given to outline the kidneys Normal uptake is seen in the adrenals and in the liver, with biliary excretion. Cushings syndrome Bilaterally symmetrical hyperplasia indicates pituitary driven hyperplasia. Bilateral asymmetric activity- nodular hyperplasia which may be independent of the pituitary control Adrenal adenoma causing cushings syndrome will show increased uptake on the side of the lesion with suppression of the contralateral gland Adrenal carcinoma – absence of uptake on both sides Adrenal cortex radionuclide imaging : Adrenal cortex radionuclide imaging Conn’s syndrome Unilateral uptake is seen on the side of the adenoma As Conn's adenomas do not suppress ACTH production the contralateral adrenal remains active Sensitivity of the scintigraphy is increased by dexamethasone suppression Adrenal Medulla Radionuclide Imaging : Adrenal Medulla Radionuclide Imaging Radiopharmaceuticals Metaiodobenzylguanidine (mIBG) is a nor epinephrine precursor analogue Concentrated in cells of neural crest origin particularly in adrenal medulla but also in salivary glands, myocardium, lungs and spleen After initial cellular uptake mIBG undergoes little or no further metabolism and 50 % is excreted by kidneys in first 24 h and 80 % within 4 days Major application is detection of pheochromocytoma and neuroblastoma and their metastasis Adrenal Medulla Radionuclide Imaging : Adrenal Medulla Radionuclide Imaging Drugs which interfere in uptake of mIBG should be stopped 1-3 days before the test. Thyroid blockade with lugols iodine should be done Diagnostic studies – I123-mIBG which offers better imaging characteristics than I131-mIBG Administered activity of 150-200 MBq of I 123 –mIBG delivers whole body dose of 8-10 mSv Images of whole body obtained at 4 and 24 h Adrenal medulla radionuclide imaging : Adrenal medulla radionuclide imaging Scintigraphy with mIBG is highly accurate in localization of the Pheochromocytomas with sensitivity of > 90 % The sensitivity of mIBG for detecting primary neuroblastoma is >90 % and more sensitive than bone scan in finding bone metastasis CONDITIONS ASSOCIATED WITH HYPERFUNCTIONING ADRENAL GLANDS : CONDITIONS ASSOCIATED WITH HYPERFUNCTIONING ADRENAL GLANDS Cushing’s syndrome –excess circulating glucocorticoids ACTH – NON DEPENDANT ACTH -DEPENDANT PITUITARY HYPERSECRECTION ECTOPIC ACTH PRODUCTION ADRENAL ADENOMA ADRENAL CARCINOMA Pituitary hyper secretion – 70 % ACTH independant adrenal lesions – 20 % ACTH dependant ectopic tumors – 10 % Cushings syndrome : Cushings syndrome Adrenals are imaged when pituitary has been excluded as causative agent. Adrenal adenomas responsible for cushings syndrome are 2-4 cm low density lesions often eccentric in location. Adrenal carcinoma are large mixed density masses (10-15 cm) Radiologist should observe the thickness of the of the unaffected limb when evaluating adrenal nodule in cushings syndrome. Cortisol producing adenomas suppress ACTH levels resulting in atrophy of remaining tissue. Adrenal hyperplasia secondary to pituitary causes. Adrenal adenomas : Adrenal adenomas CONN’S SYNDROME( PRIMARY HYPERALDOSTERONISM) : CONN’S SYNDROME( PRIMARY HYPERALDOSTERONISM) Hypersecretion of aldosterone, moderate hypertension and hypokalemia. Etiologies Unilateral aldosterone secreting adrenal adenoma(60%) Less than 2 cm Solitary Frequently eccentric Adrenal hyperplasia(40 %) Very rarely adrenal adenocarcinoma CT, MRI or adrenal vein sampling Adrenogenital syndromes : Adrenogenital syndromes Excessive secretion of the sex hormones – virilization, feminization or precocious puberty Androgen excess m/c – 80 % in female population Imaging finding – uniformly enlarged adrenal glands Both benign adenomas and adrenocortical carcinomas give rise to Adrenogenital syndrome PHEOCHROMOCYTOMA : PHEOCHROMOCYTOMA Rare tumor of chromaffin cells in adrenal medulla 1 in 20,000 individuals Secrete both epinephrine and nor epinephrine Severe headaches , palpitations, excess sweating, tremor , anxiety and hypertension. 3-10 % detected in asymptomatic patients 10 % rule Extra adrenal in 10 % Bilateral in 10 % Malignant in 10 % Pheochromocytoma : Pheochromocytoma Asssociations MEN type IIA and IIB Von Hipple Lindua disease Neurofibromatosis Struge Weber syndrome Paraganglioma- Extra adrenal catecholamine secreting tumors Paraganglioma are associated with increased risk of malignancy in itself and increased risk of associated neoplasm's Pheochromocytoma and Paraganglioma vary little in imaging Pheochromocytomas : Pheochromocytomas Imaging is performed to localise tumor that is already diagnosed clinically or biochemically Radiologists role is to identify if the Pheochromocytoma is unilateral or bilateral and whether it is metastatic Paraganglioma can occur anywhere neural crest cells are present Reported from base of skull to epididymis. Most common location is retroperitoneum CT scan of entire abdomen is done to identify ectopic tumour Pheochromocytomas : Pheochromocytomas Pheochromocytomas are typically intra-adrenal masses that range in size from 1 cm to 20 cm (average -5 cm) Smaller when they are bilateral and associated with MEN syndrome Well defined oval or round masses with homogenous density and occasionally have foci of calcification, central necrosis or cystic change Often enhance uniformly Pheochromocytomas : Pheochromocytomas MRI- On T1 weighted – low signal intensity On T2 weighted – Hyperintense signal (although described as “lightbulb bright” on T2 weighted images this finding is neither sensitive nor specific as they are more often heterogeneous Pheochromocytoma do not demonstrate loss of signal intensity on chemical shift imaging Typically enhance avidly on contrast administration MIBG is the only definitive test to date Pheochromocytomas : Pheochromocytomas The imaging finding as well as pathological evaluation in the benign as well as malignant Pheochromocytomas are nearly identical Only the presence of metastasis can clearly define a pheochromocytoma as malignant Imaging of recurrent pheochromocytomas and paragangliomas is more complex, and MIBG scintigraphy is extremely valuable Pheochromocytoma : Pheochromocytoma Pheochromocytoma : Pheochromocytoma Adrenal Hypofunction : Adrenal Hypofunction Hypofunction primarily refers to disorders of adrenal cortex No syndromes of medullary hypofunction are described May be due to destruction of adrenals (secondary) or due to inadequate pituitary stimulation (primary) Lethargy , fatigue and weakness. Weight loss, anorexia, abdominal pain and hypotension. POTENTIAL CAUSES OF ADRENOCORTICAL FALIURE : POTENTIAL CAUSES OF ADRENOCORTICAL FALIURE Autoimmune disorders Infections (fungal and TB) Drugs that inhibit cortical synthesis (ketoconazole, etomidate) or increase cortical clearance (barbiturates and phenytoin) Adrenal haemorrhage Metastasis Sarcoidosis Haemochromatosis Adrenal hematoma : Adrenal hematoma Traumatic hematoma 28 % of significant abdominal trauma Arise in the medulla and stretch the cortex Seen in 90 % on the right side CT- modality of choice Round to oval adrenal hematoma(83% cases) Diffuse irregular hemorrhage obliterating the gland (9% cases) Uniform adrenal enlargement (9% cases) Hematoma vary in attenuation depending on the age Acute to subacute HU 50 to 90 Gradually decrease in size and attenuation May develop calcification Biopsy may be required to differentiate it from metastasis Non traumatic adrenal hematoma : Non traumatic adrenal hematoma Adrenal hematoma on MRI : Adrenal hematoma on MRI Adrenal Metastasis : Adrenal Metastasis The adrenal gland is a common site for metastatic disease, most commonly from carcinomas (lung, breast, and colon), lymphoma, and melanoma, although virtually any primary malignancy can metastasize to the adrenal gland CT –enlarged and irregular margins Usually bilateral and have inhomogeneous center with enhancing rim Have HU >20 on non enhanced scans More intense persistent enhancement than adenomas MRI – low SI on T1 , high if hemorrhagic and Hyperintense on T2 Adrenal metastasis : Adrenal metastasis Adrenal metastasis : Adrenal metastasis Adrenocortical carcinoma : Adrenocortical carcinoma Adrenal carcinoma is rare Are larger than 6 cm when detected, despite the fact that 50% of patients present with Cushing syndrome(from Cortisol Hypersecretion) or, more rarely, Conn syndrome or Adrenogenital syndrome Lesions are typically heterogeneous and irregular, show areas of cystic change and calcification is seen in up to 30% of cases. Heterogeneously enhancing Low on SI on T1 and high SI on T2 when compared to liver HCC : HCC Myelolipoma : Myelolipoma Variable mixture of fat and hematopoietic elements Myelolipomas are usually detected incidentally at CT Although mostly small, they can occasionally be large, hemorrhagic, or, rarely, extraadrenal Specific imaging features on CT or MR imaging due to their abundance of mature fat The amount of recognizable macroscopic fat varies from almost 100% to none. The presence of even the slightest macroscopic fat indicates that the lesion is a Myelolipoma Myelolipomas : Myelolipomas When a Myelolipomas large (5 cm), the myeloid elements have a tendency to hemorrhage CT- large, well defined, encapsulated. Hallmark recognition of gross fat within the lesion (HU ranges from -150 to -50) soft tissue component may enhance after contrast administration Exception is “Collision tumor” in which a myelolipoma and metastasis co-exists Myelolipomas : Myelolipomas MRI occasionally be helpful by demonstrating high fat signal intensity on T1- and T2-weighted images which is reduced on fat suppression images Chemical shift imaging may or may not be helpful, depending on the proportion of fat to water in an MR imaging voxel, since pure fat may demonstrate no signal intensity decrease on opposed-phase images Myelolipoma : Myelolipoma Myelolipoma : Myelolipoma Adrenal cysts : Adrenal cysts Found incidentally at imaging or autopsy Endothelial in 45%, pseudocyst in 40 % epithelial in 10 % and parasitic in 5 % Endothelial cysts are most often lymphangiomatous and contain clear fluid, pseudocyst from previous injury or hemorrhage Imaging- simple cysts solitary well circumscribed. Uniform attenuation on CT, punctate calcification may be seen. Wall may enhance on CT and MRI MRI- low SI T1 and high SI on T2 Echinococal cysts are complex and difficult to differentiate from cystic neoplasm Pseudolesions : Pseudolesions You do not have the permission to view this presentation. In order to view it, please contact the author of the presentation.
adrenal imaging ppt drvivektewari Download Post to : URL : Related Presentations : Share Add to Flag Embed Email Send to Blogs and Networks Add to Channel Uploaded from authorPOINT lite Insert YouTube videos in PowerPont slides with aS Desktop Copy embed code: (To copy code, click on the text box) Embed: URL: Thumbnail: WordPress Embed Customize Embed The presentation is successfully added In Your Favorites. Views: 543 Category: Entertainment License: All Rights Reserved Like it (7) Dislike it (0) Added: December 20, 2010 This Presentation is Public Favorites: 0 Presentation Description Radiological Imaging of Adrenal Gland Comments Posting comment... By: myoushani (1 month(s) ago) so many thanks for this great lecture may i download it thanks Saving..... Post Reply Close Saving..... Edit Comment Close By: khudur (12 month(s) ago) great presentation . would you please give me the permission to download it . thank you Saving..... Post Reply Close Saving..... Edit Comment Close By: yasmineg (14 month(s) ago) how can i download plz? Saving..... Post Reply Close Saving..... Edit Comment Close By: hoangtubui (14 month(s) ago) How can i download this file? Saving..... Post Reply Close Saving..... Edit Comment Close Premium member Presentation Transcript Adrenal imaging : Adrenal imaging Introduction : Introduction Among most important and vital endocrine organ Small bilateral yellowish retroperitoneal organ Lies just above kidney in gerota’s fascia 2 Anatomy : Anatomy 3 Right adrenal is triangular, related to upper pole Right kidney Left adrenal is crescent shaped, related to upper and medial part Left kidney Average size is 3-5 cm long, 2-3 cm wide and 5 mm in thickness Average weight is 3-5 g of which 90 % is contributed by cortex. Most frequent shapes of the adrenals : Most frequent shapes of the adrenals Embryology : Embryology 5 Cortex is mesodermal in origin Week 4 – 6 : start from coelomic mesoderm adjacent to urogenital ridge Week 8 : differentiate into thin definite outer cortex and thick inner fetal cortex Cont: : Cont: 6 Fetal cortex produce steroid during gestation and involutes at birth Definite cortex develop into functional adrenal cortex Embryology : Embryology 7 Medulla derived from neural crest cells Develop with sympathetic nervous system Week 5 : neural crest cell migrate to Para-aortic and Para-vertebral region towards medial aspect of adrenal cortex Cont: : Cont: 8 Extra adrenal chromaffin cells located to the left of aortic bifurcation near the origin of IMA Embryology : Embryology 9 Embryology : Embryology 10 Embryology : Embryology 11 Embryology : Embryology 12 Physiology : Physiology Adrenal gland has two distinct zones Adrenal cortex Adrenal medulla 13 Physiology : Physiology 14 Adrenal cortex produces -Glucocorticoids (Zona Fasciculata) -Mineralocorticoids (Zona Glomerulosa) -Adrenal androgens (Zona Reticularis) Physiology : Physiology 15 Adrenal medulla produces -Epinephrine (adrenaline) -Norepinehrine (noradrenaline) Help inc in cardiac output, vascular resistance and mediate stress response All are absolutely required for life Functions : Functions 16 Aldosterone helps in Na reabsorption & potassium excretion & preventing dehydration Cortisol stimulate protein breakdown, inhibition of tissue response in injury & antagonism to action of insulin Androgens helps in early development of male sex organ in childhood Functions : Functions 17 Slide 18: 18 Relations : Relations RT ADRENAL Anteriorly IVC Liver Posteriorly Diaphragm LT ADRENAL Anteriorly Pancreas Stomach Posteriorly Diaphragm 19 Relations : Relations Vascular supply : Vascular supply 21 Blood to adrenal supplied by Inferior phrenic artery (superiorly) Aorta (medially) Renal artery (inferiorly) Vascular supply : Vascular supply 22 Right Adrenal : drained to IVC via adrenal vein Left Adrenal : drained into left adrenal vein or directly to IVC Lymphatics : drained to Para-aortic and para-caval lymph nodes IMAGING INVESTIGATION : IMAGING INVESTIGATION Plain Radiography Intravenous urography Retroperitoneal air insufflation Arteriography Phlebography Inferior vena cavagraphy Hormone assay Ultrasound CT scanning MRI Needle biopsy Plain Radigraphy : Plain Radigraphy Mass Masses smaller than 5 cm are not visualised Seen displacing the kidney Calcifications Idiopathic Neoplasm Granuloma Cyst Old haemorrhage Wolmans disease Incidental adrenal lesion (IAL) : Almost all incidental adrenal lesions(IALs) in patients without a known primary cancer are benign. Characterization of IALs in cancer patients predict prognosis to assess staging to direct therapy Almost all IALs are characterized by using imaging alone, although some lesions require percutaneous biopsy for definitive characterization. Characterization depends on lesion morphology perfusion differences between benign and malignant masses the intracellular lipid concentration of the mass and the metabolic activity of the mass CT contrast medium washout tests offer the highest test sensitivity and specificity for IAL characterization Incidental adrenal lesion (IAL) CT Scan-Incidental adrenal lesion (IAL) : CT Scan-Incidental adrenal lesion (IAL) Primary imaging tool Targeted scan-adrenal only or non targeted scan - the entire abdomen Slice thickness -2.5 mm Contrast enhanced scans 100-150 ml at rate of 3 ml per second . between 25 and 40 seconds for arterial or parenchymal phase at 70 seconds after contrast injection for routine portovenous phase Delayed imaging done at 10 or 15 min CT SCAN : CT SCAN Lesion Size A definitive size threshold cannot be used to confidently distinguish benign from malignant lesions with diameter as the only imaging finding The appropriateness criteria of the American College of Radiology emphasize that management with respect to lesion size depends on whether patients have a history of malignancy; in those who do not, benign-appearing tumors smaller than 3 cm likely are benign Excision is generally advised for incidentally discovered masses larger than 5 cm Morphological appearance IAL : Morphological appearance IAL Adrenal size : Adrenal size Precontrast Attenuation : Precontrast Attenuation Lee et al explained the importance of centering the ROI within the lesion to avoid partial volume effects and beam-hardening artifacts, which are most pronounced in the periphery. In their 1998 review, Boland et al described the circular ROI and indicated that the circle must be large enough to cover at least one half of the cross-sectional area of the mass. Precontrast attenuation : Precontrast attenuation Precontrast attenuation : Precontrast attenuation Many investigators use a cutoff of less than 10 HU to diagnose an adenoma, a technique supported by the American College of Radiology appropriateness criteria Adenomas with higher pre contrast attenuation may identified by performing delayed contrast material– enhanced CT to measure washout characteristics Percentage washout formulas : Percentage washout formulas Percentage washout : Percentage washout Percentage washout : Percentage washout Histogram Analysis : Histogram Analysis MRI : MRI Single most important imaging protocol –chemical shift imaging Chemical shift imaging is performed with in-phase and opposed phase T1 weighted GRE technique. A coronal T2 weighted image without fat suppression Axial T2 weighted image with fat suppression If adrenal mass is not found to be adenoma on chemical shift imaging – Pre and post GAD gradient echo imaging with fat suppression Chemical shift imaging : Chemical shift imaging Adrenal venous sampling : Adrenal venous sampling Each adrenal vein catheterized via transfemoral or transjugular route Bilateral adrenal vein samples are tested for aldosterone in an attempt to localise the functional tumor to one gland Performed under continuous infusion of ACTH which acutely stimulates aldosterone Cortisol is measured to prove that the samples are taken from the adrenal vein Adrenal venous sampling : Adrenal venous sampling Ultrasound : Ultrasound Primarily reserved for use in pediatric population Right adrenal completely imaged in 90 % Left adrenal imaged in 80 % Visualised from the mid-axillary, anterior axillary, posterior axillary and sub costal oblique approach Structures mistaken to be adrenals Diaphragmatic crus Gastric diverticulum Renal or retroperitoneal masses Accessory spleen Ultrasound in evaluating adrenals : Ultrasound in evaluating adrenals In some cases the adrenal glands can be easily identified without localising the mains vessels. However, in most cases, especially if the adrenal glands are normal or small, the vessels will be needed to identify the location of the adrenal glands. Right adrenal gland : Right adrenal gland Left adrenal gland : Left adrenal gland Nuclear Medicine Imaging : Nuclear Medicine Imaging Usual role of scintigraphy is a second line test to clarify equivocal, inconclusive or unexpected results from anatomical imaging Indications Demonstrate functional status of adrenal nodules Assess function in contralateral gland To confirm bilateral disease in pituitary driven syndromes Detect extra adrenal or ectopic sites of hormone production To detect functioning metastasis in patients with primary adrenal tumors To detect recurrence after surgery Radionuclide imaging : Radionuclide imaging Adrenal cortex- Labeled cholesterol analogues given IV are incorporated into low density lipoproteins and concentrated into adrenal cortex where they join the synthetic pathway for steroid production These tracers undergo esterification but are then stored in the intracellular lipid pool Only a small portion reaches the adrenals remaining excreted in the bile Rate of clearance and excretion of the tracer is slow a long lived radionuclide is needed Most effective is 75 Se – labeled seleno-nor-cholesterol (t1/2 is 120 days) Adrenal cortex radionuclide imaging : Adrenal cortex radionuclide imaging Images are acquired 5 days and again 7 days after the injection Additional 99TC DMSA is given to outline the kidneys Normal uptake is seen in the adrenals and in the liver, with biliary excretion. Cushings syndrome Bilaterally symmetrical hyperplasia indicates pituitary driven hyperplasia. Bilateral asymmetric activity- nodular hyperplasia which may be independent of the pituitary control Adrenal adenoma causing cushings syndrome will show increased uptake on the side of the lesion with suppression of the contralateral gland Adrenal carcinoma – absence of uptake on both sides Adrenal cortex radionuclide imaging : Adrenal cortex radionuclide imaging Conn’s syndrome Unilateral uptake is seen on the side of the adenoma As Conn's adenomas do not suppress ACTH production the contralateral adrenal remains active Sensitivity of the scintigraphy is increased by dexamethasone suppression Adrenal Medulla Radionuclide Imaging : Adrenal Medulla Radionuclide Imaging Radiopharmaceuticals Metaiodobenzylguanidine (mIBG) is a nor epinephrine precursor analogue Concentrated in cells of neural crest origin particularly in adrenal medulla but also in salivary glands, myocardium, lungs and spleen After initial cellular uptake mIBG undergoes little or no further metabolism and 50 % is excreted by kidneys in first 24 h and 80 % within 4 days Major application is detection of pheochromocytoma and neuroblastoma and their metastasis Adrenal Medulla Radionuclide Imaging : Adrenal Medulla Radionuclide Imaging Drugs which interfere in uptake of mIBG should be stopped 1-3 days before the test. Thyroid blockade with lugols iodine should be done Diagnostic studies – I123-mIBG which offers better imaging characteristics than I131-mIBG Administered activity of 150-200 MBq of I 123 –mIBG delivers whole body dose of 8-10 mSv Images of whole body obtained at 4 and 24 h Adrenal medulla radionuclide imaging : Adrenal medulla radionuclide imaging Scintigraphy with mIBG is highly accurate in localization of the Pheochromocytomas with sensitivity of > 90 % The sensitivity of mIBG for detecting primary neuroblastoma is >90 % and more sensitive than bone scan in finding bone metastasis CONDITIONS ASSOCIATED WITH HYPERFUNCTIONING ADRENAL GLANDS : CONDITIONS ASSOCIATED WITH HYPERFUNCTIONING ADRENAL GLANDS Cushing’s syndrome –excess circulating glucocorticoids ACTH – NON DEPENDANT ACTH -DEPENDANT PITUITARY HYPERSECRECTION ECTOPIC ACTH PRODUCTION ADRENAL ADENOMA ADRENAL CARCINOMA Pituitary hyper secretion – 70 % ACTH independant adrenal lesions – 20 % ACTH dependant ectopic tumors – 10 % Cushings syndrome : Cushings syndrome Adrenals are imaged when pituitary has been excluded as causative agent. Adrenal adenomas responsible for cushings syndrome are 2-4 cm low density lesions often eccentric in location. Adrenal carcinoma are large mixed density masses (10-15 cm) Radiologist should observe the thickness of the of the unaffected limb when evaluating adrenal nodule in cushings syndrome. Cortisol producing adenomas suppress ACTH levels resulting in atrophy of remaining tissue. Adrenal hyperplasia secondary to pituitary causes. Adrenal adenomas : Adrenal adenomas CONN’S SYNDROME( PRIMARY HYPERALDOSTERONISM) : CONN’S SYNDROME( PRIMARY HYPERALDOSTERONISM) Hypersecretion of aldosterone, moderate hypertension and hypokalemia. Etiologies Unilateral aldosterone secreting adrenal adenoma(60%) Less than 2 cm Solitary Frequently eccentric Adrenal hyperplasia(40 %) Very rarely adrenal adenocarcinoma CT, MRI or adrenal vein sampling Adrenogenital syndromes : Adrenogenital syndromes Excessive secretion of the sex hormones – virilization, feminization or precocious puberty Androgen excess m/c – 80 % in female population Imaging finding – uniformly enlarged adrenal glands Both benign adenomas and adrenocortical carcinomas give rise to Adrenogenital syndrome PHEOCHROMOCYTOMA : PHEOCHROMOCYTOMA Rare tumor of chromaffin cells in adrenal medulla 1 in 20,000 individuals Secrete both epinephrine and nor epinephrine Severe headaches , palpitations, excess sweating, tremor , anxiety and hypertension. 3-10 % detected in asymptomatic patients 10 % rule Extra adrenal in 10 % Bilateral in 10 % Malignant in 10 % Pheochromocytoma : Pheochromocytoma Asssociations MEN type IIA and IIB Von Hipple Lindua disease Neurofibromatosis Struge Weber syndrome Paraganglioma- Extra adrenal catecholamine secreting tumors Paraganglioma are associated with increased risk of malignancy in itself and increased risk of associated neoplasm's Pheochromocytoma and Paraganglioma vary little in imaging Pheochromocytomas : Pheochromocytomas Imaging is performed to localise tumor that is already diagnosed clinically or biochemically Radiologists role is to identify if the Pheochromocytoma is unilateral or bilateral and whether it is metastatic Paraganglioma can occur anywhere neural crest cells are present Reported from base of skull to epididymis. Most common location is retroperitoneum CT scan of entire abdomen is done to identify ectopic tumour Pheochromocytomas : Pheochromocytomas Pheochromocytomas are typically intra-adrenal masses that range in size from 1 cm to 20 cm (average -5 cm) Smaller when they are bilateral and associated with MEN syndrome Well defined oval or round masses with homogenous density and occasionally have foci of calcification, central necrosis or cystic change Often enhance uniformly Pheochromocytomas : Pheochromocytomas MRI- On T1 weighted – low signal intensity On T2 weighted – Hyperintense signal (although described as “lightbulb bright” on T2 weighted images this finding is neither sensitive nor specific as they are more often heterogeneous Pheochromocytoma do not demonstrate loss of signal intensity on chemical shift imaging Typically enhance avidly on contrast administration MIBG is the only definitive test to date Pheochromocytomas : Pheochromocytomas The imaging finding as well as pathological evaluation in the benign as well as malignant Pheochromocytomas are nearly identical Only the presence of metastasis can clearly define a pheochromocytoma as malignant Imaging of recurrent pheochromocytomas and paragangliomas is more complex, and MIBG scintigraphy is extremely valuable Pheochromocytoma : Pheochromocytoma Pheochromocytoma : Pheochromocytoma Adrenal Hypofunction : Adrenal Hypofunction Hypofunction primarily refers to disorders of adrenal cortex No syndromes of medullary hypofunction are described May be due to destruction of adrenals (secondary) or due to inadequate pituitary stimulation (primary) Lethargy , fatigue and weakness. Weight loss, anorexia, abdominal pain and hypotension. POTENTIAL CAUSES OF ADRENOCORTICAL FALIURE : POTENTIAL CAUSES OF ADRENOCORTICAL FALIURE Autoimmune disorders Infections (fungal and TB) Drugs that inhibit cortical synthesis (ketoconazole, etomidate) or increase cortical clearance (barbiturates and phenytoin) Adrenal haemorrhage Metastasis Sarcoidosis Haemochromatosis Adrenal hematoma : Adrenal hematoma Traumatic hematoma 28 % of significant abdominal trauma Arise in the medulla and stretch the cortex Seen in 90 % on the right side CT- modality of choice Round to oval adrenal hematoma(83% cases) Diffuse irregular hemorrhage obliterating the gland (9% cases) Uniform adrenal enlargement (9% cases) Hematoma vary in attenuation depending on the age Acute to subacute HU 50 to 90 Gradually decrease in size and attenuation May develop calcification Biopsy may be required to differentiate it from metastasis Non traumatic adrenal hematoma : Non traumatic adrenal hematoma Adrenal hematoma on MRI : Adrenal hematoma on MRI Adrenal Metastasis : Adrenal Metastasis The adrenal gland is a common site for metastatic disease, most commonly from carcinomas (lung, breast, and colon), lymphoma, and melanoma, although virtually any primary malignancy can metastasize to the adrenal gland CT –enlarged and irregular margins Usually bilateral and have inhomogeneous center with enhancing rim Have HU >20 on non enhanced scans More intense persistent enhancement than adenomas MRI – low SI on T1 , high if hemorrhagic and Hyperintense on T2 Adrenal metastasis : Adrenal metastasis Adrenal metastasis : Adrenal metastasis Adrenocortical carcinoma : Adrenocortical carcinoma Adrenal carcinoma is rare Are larger than 6 cm when detected, despite the fact that 50% of patients present with Cushing syndrome(from Cortisol Hypersecretion) or, more rarely, Conn syndrome or Adrenogenital syndrome Lesions are typically heterogeneous and irregular, show areas of cystic change and calcification is seen in up to 30% of cases. Heterogeneously enhancing Low on SI on T1 and high SI on T2 when compared to liver HCC : HCC Myelolipoma : Myelolipoma Variable mixture of fat and hematopoietic elements Myelolipomas are usually detected incidentally at CT Although mostly small, they can occasionally be large, hemorrhagic, or, rarely, extraadrenal Specific imaging features on CT or MR imaging due to their abundance of mature fat The amount of recognizable macroscopic fat varies from almost 100% to none. The presence of even the slightest macroscopic fat indicates that the lesion is a Myelolipoma Myelolipomas : Myelolipomas When a Myelolipomas large (5 cm), the myeloid elements have a tendency to hemorrhage CT- large, well defined, encapsulated. Hallmark recognition of gross fat within the lesion (HU ranges from -150 to -50) soft tissue component may enhance after contrast administration Exception is “Collision tumor” in which a myelolipoma and metastasis co-exists Myelolipomas : Myelolipomas MRI occasionally be helpful by demonstrating high fat signal intensity on T1- and T2-weighted images which is reduced on fat suppression images Chemical shift imaging may or may not be helpful, depending on the proportion of fat to water in an MR imaging voxel, since pure fat may demonstrate no signal intensity decrease on opposed-phase images Myelolipoma : Myelolipoma Myelolipoma : Myelolipoma Adrenal cysts : Adrenal cysts Found incidentally at imaging or autopsy Endothelial in 45%, pseudocyst in 40 % epithelial in 10 % and parasitic in 5 % Endothelial cysts are most often lymphangiomatous and contain clear fluid, pseudocyst from previous injury or hemorrhage Imaging- simple cysts solitary well circumscribed. Uniform attenuation on CT, punctate calcification may be seen. Wall may enhance on CT and MRI MRI- low SI T1 and high SI on T2 Echinococal cysts are complex and difficult to differentiate from cystic neoplasm Pseudolesions : Pseudolesions