Radiology of Endocrine System PDF

Imaging of the endocrine system Presented by Heba Hassan, PhD, MD Assistant Professor of Medical Imaging, Women’s Imaging Unit & Team Coordinator Alexandria University Ground rul...

Imaging of the endocrine system Presented by Heba Hassan, PhD, MD Assistant Professor of Medical Imaging, Women’s Imaging Unit & Team Coordinator Alexandria University Ground rules AGENDA  Imaging modalities Ionizing radiation Non-ionizing radiation X-ray – Radiographs/ mammography CT Fluoroscopy / Angiography Nuclear medicine US – 2D/ 3D/ 4D/ Doppler MRI  Thyroid and Parathyroids Schematic diagram of the thyroid and parathyroid glands (green dots) and their relationship to important anatomical landmarks. A. Frontal view. B. Axial cross-section Thyroid and Parathyroids Thyroid – US anatomy Thyroid – US anatomy Sagittal plane Axial plane Homogenous - echogenic/ hyperechoic to the overlying hypoechoic strap muscles  Thyroid – US anatomy color Doppler image of thyroid showing normal vascularity. Thyroid – US anatomy Spectral Doppler flow – low resistive wave Thyroid – US anatomy Transverse dimension (width-W) and anterior-posterior Length (L) of the lobes is 4–5 cm. (depth- D) dimension are approximately 2 cm each Measured longitudinally consistent way to assess the thyroid size is by measuring the volume = measured using π/6 (W × D × L) or (W × D × L) ÷ 2 Thyroid – CT anatomy US - Axial plane CT - Axial plane Thyroid hyperdense on CT Thyroid – CT anatomy CT non-contrast - Axial CT with contrast - Axial plane plane Thyroid always hyperdense on CT due to iodine content on non-contrast + iodine uptake on contrast phase Thyroid – CT anatomy Thyroid hyperdense on CT + hyperintense on MRI due to iodine content Thyroid – CT anatomy Axial plane Coronal plane Thyroid always hyperdense – iodine uptake in contrast Thyroid – Pathologies Notice the bulge – convex not flattened outline Thyroid – Pathologies AGENESIS OF THE THYROID GLAND = congenital absence of the entire thyroid Thyroid – Pathologies ??? AGENESIS OF THE THYROID GLAND  Thyroid – Pathologies ECTOPIC THYROID GLAND Thyroid scan with ultrasound image of the floor of the mouth, revealing presence of thyroid glandular tissue suprasternal marker CT axial image of the floor of the mouth Confirm dense ectopic thyroid tissue. Thyroid – Pathologies HEMIGENESIS = congenital absence of one lobe of the thyroid Thyroid – Pathologies normal sized right lobe of thyroid gland hypoplastic left lobe of thyroid gland Congenital hypoplasia of thyroid gland Thyroid – Pathologies Graves disease Typical sonographic features enlarged, heterogeneous and hypoechoic. Doppler - diffusely increased vascularity = ‘thyroid inferno’ or "thyroid storm". Thyroid – Pathologies Graves disease Typical sonographic features enlarged, heterogeneous and hypoechoic. Doppler - diffusely increased vascularity = ‘thyroid inferno’ or "thyroid storm". Thyroid-Associated Orbitopathy (TAO) Thyroid – Pathologies Thyroid – Pathologies Thyroid – Pathologies Hashimoto thyroiditis gland may appear enlarged, normal, or reduced in size on an US scan, depending on the stage and severity of the disease. Initially, may appear enlarged due to inflammation, causing transitory elevation of thyroid hormones («hashitoxicosis») But over time, it may become scarred and atrophied, resulting in a smaller-than-normal gland and hypothyroidism Thyroid gland – Nuclear Medicine Studies Scintigraphy + PET-CT  Thyroid – Pathologies Thyroid nodules Colloid cysts Suspicious Colloid cysts nodule Thyroid – Pathologies Probably benign nodule Suspicious nodule Ultrasonography Guided Fine Needle Aspiration (FNA)  Thyroid – Pathologies Contrast-enhanced computed tomography scans and MRI are useful in evaluating the extension and invasion of tumor into the adjacent neck structures including metastatic lymph nodes and lung metastasis MRI is superior to CT for assessing invasion of trachea/oesophagus (less suited for the lungs) Thyroid gland – Nuclear Medicine Studies Malignant nodule carcinoma Isotope scan / scintigraphy PET-CT Parathyroid gland – Pathologies When normal, they are usually not identifiable. When enlarged, these structures display as hypoechoic nodules, may compress the adjacent anterior thyroid parenchyma and can erroneously be classified as thyroid nodules. Parathyroid gland – Pathologies Parathyroid gland – Pathologies US + Doppler US + Isotope/ CT – contrast scintigraphy + PET-CT  Parathyroid gland – Pathologies Normal Osteoporosis Normal Osteolysis Normal Osteoporosis = Subperiosteal Brown tumor resorption Pituitary Gland Pituitary Gland Pituitary Gland Schematic diagram of the sella turcica (sagittal view) with Schematic diagram of the sella turcica with the pituitary gland (coronal view). The the anterior and posterior parts of the pituitary gland cavernous sinuses are rendered in blue. The internal carotid artery and cranial nerves (adenohypophysis and neurohypophysis). III, IV, V1, V2 and VI traverse the cavernous sinuses. Superiorly the main suprasellar structure located in proximity is the optic chiasm. Pituitary Gland Schematic diagram of the sella turcica (sagittal view) with Schematic diagram of the sella turcica with the pituitary gland (coronal view). The the anterior and posterior parts of the pituitary gland cavernous sinuses are rendered in blue. The internal carotid artery and cranial nerves (adenohypophysis and post-hypophysis). III, IV, V1, V2 and VI traverse the cavernous sinuses. Superiorly the main suprasellar structure located in proximity is the optic chiasm. Pituitary gland – anatomy Sagittal T1 weighted unenhanced image of the pituitary fossa Anterior pituitary tissue (adenohypophysis), A posterior pituitary (neurohypophysis), bright spot (vasopressin), P, The stalk (arrow) with a small cleft of CSF visible within –the infundibular recess of the third ventricle. The optic chiasm, C, and mamillary bodies, M, are seen in the suprasellar region. B - brainstem, S - sphenoid air sinus, CL - clivus. Pituitary gland – anatomy Coronal T1 weighted unenhanced image of the pituitary fossa. Anterior pituitary gland (adenohypophysis), A, Posterior pituitary (neurohypophysis), bright spot (vasopressin) visible centrally, P. he stalk is seen extending up into the suprasellar region. The optic chiasm, C, is visible. The cavernous segments of the carotid arteries, I, are seen within the cavernous sinuses, which form the lateral boundaries of the pituitary fossa. Pituitary gland – anatomy Coronal T2 weighted unenhanced image Coronal T1 weighted unenhanced image Pituitary gland – anatomy Sagittal T1 weighted unenhanced image Sagittal T1 weighted enhanced image  Pituitary gland – anatomy Sagittal T1 weighted unenhanced image Sagittal T2 weighted unenhanced image  Pituitary gland – Pathologies pituitary microadenomas = less than 10 mm in size pituitary macroadenomas = over 10mm in size Pituitary gland – Pathologies Pituitary gland – Pathologies pituitary maroadenomas = over 10 mm in size Pituitary gland – Pathologies “snowman’” configuration. pituitary maroadenomas = over 10 mm in size  Pituitary gland – Pathologies Craniopharyngioma CT best in showing calcifications MRI best in showing relation to other structures Craniopharyngioma = benign tumor – frequent in the pediatric population Craniopharyngioma = partially cystic + calcifications  Pituitary gland – Pathologies partially empty sella, filled with cerebrospinal post contrast shows an enlarged pituitary fluid. gland and stalk (arrow) with homogenous The pituitary gland is small and compressed n contrast enhancement due to inflammation the floor of the pituitary fossa Compression symptoms Cyst with mass effect on the neurohypophysis and in contact with the optic chiasm Adrenal Glands Schematic illustration of the adrenal Schematic drawing of an adrenal gland glands and surrounding anatomic and its different components. structures (coronal view). Adrenal gland – anatomy Ultrasonography is the method of choice in the assessment of the adrenal glands in neonates and young children  Adrenal gland – anatomy Their shapes may or may not resemble bilaterally either but are largely normally confined into; pyramidal, crescentic, lambda, y, comma, or wishbone-shaped appearances when normal with both having a body and 2 limbs  Adrenal gland – anatomy Trilaminar appearance = central echogenic/ hyperechoic medulla and surrounding hypoechoic cortex  Adrenal gland – anatomy CT non-contrast - Axial CT with contrast - Axial CT with contrast - Coronal plane plane plane  Adrenal gland – anatomy MRI in phase - Axial plane MRI out of phase - Axial plane MRI out of phase – Coronal plane Performed to identify intra-cellular fat = in cases of adenoma (signal drop = dark) Clue = look at the vertebral body = if dark – intracellular fatty marrow Adrenal gland – Pathology  Adrenal gland – Pathology CT with contrast - Axial CT with contrast - Axial CT non-contrast - Axial plane plane plane CT (density – 15 to 5 HU < 10 HU).  Adrenal gland – Pathology CT with contrast - Axial CT with contrast - Coronal plane Coarse rounded, peripheral or septal calcifications are typically benign plane Bilateral calcifications also suggest a benign origin. and may be seen in: Adenoma Myelolipoma Trauma Granulomatous infection Adrenal gland – Pathology CT non-contrast - Axial MRI in phase - Axial plane MRI out of phase - Axial plane plane Indeterminate lesion on the nonenhanced CT (density 24 HU > 10 HU). Signal drop on out-of-phase imaging compared to in-phase imaging LIPID POOR ADENOMA  Adrenal gland – Pathology Pheochromocytoma CT with contrast - Axial PET- CT - Axial plane MRI T2W - Axial plane MRI T1W post-contrast - Axial plane plane Contrast-enhanced CT (A) and PET –CT fusion intense On MRI, the lesion has a high signal on T2W (light bulb sign) (C) tracer uptake in heterogenous enhancing right adrenal and cystic unenhanced portions on T1W post contrast (D) mass. sequences. Adrenal gland – Pathology Adrenocortical carcinoma CT with contrast - Axial CT with contrast - Coronal plane plane Heterogenous enhancing right adrenal mass of 7 cm > 4 cm Punctate, irregular calcifications are not typically benign and can be seen in: Adrenocortical cancer Adrenal metastases TAKE HOME MASSAGES The first line of imaging modality for endocrine system components depends on the type of organ you are imaging: Thyroid gland = Ultrasound Parathyroid gland = US Pituitary gland = MRI Adrenals = US in neonates and children – CT in adults TAKE HOME MASSAGES Complimentary imaging modalities: Thyroid gland CT - MRI = staging of tumors, ectopic site Nuclear = activity Parathyroid gland CT = localization - staging of tumors, verify the site Nuclear = activity Pituitary gland CT in case of craniopharyngioma = calcifications Adrenals TAKE HOME MASSAGES Thyroid gland Appears homogenous and echogenic/ hyperechoic on US Appears hyperdense on CT both before and after contrast due to iodine content Size matters - measured in two view Graves’ disease – enlarged, heterogenous, hypermetabolic (increased vascularity on Doppler + hot gland on scintigraphy) Initial stage of Hashimoto cannot be differentiated from Graves’ disease on imaging TI-RADS system to stratify thyroid nodules = from benign to malignant spectrum TAKE HOME MASSAGES Parathyroid gland If normal not identifiable in all imaging modalities Once identified – pathological, most common adenoma Once identified ask for further investigations (effect of hyperparathyroidism) TAKE HOME MASSAGES Pituitary gland MRI is the imaging modality to assess pituitary pathologies Anterior and posterior lobes are distinguished by T1-W sequence, posterior bright Microadenoma and small macroadenomas cannot be identified on CT Microadenoma can sometimes not be identified without contrast Macroadenoma causes mass effect – other symptomatology than endocrine CT can identify calcifications in cases of craniopharyngioma TAKE HOME MASSAGES Adrenal gland Layers of cortex and medulla are identified in neonates and young children by US Not identifiable in adults by US – identifiable by CT Once lesion identified in suprarenal fossa by US further investigation to verify if adrenal or not (renal, hepatic, splenic) Fat plays as key role in differentiating adenoma from carcinoma Fat identified on CT = lipid-rich adenoma, no need for MRI Fat not identified on CT = lipid-poor versus carcinoma, need for MRI to differentiate MRI sequence in phase out of phase to detect intra-cellular fat Adenoma if < 10 HU, if > 10 HU lipid-poor versus carcinoma, need for MRI to differentiate Size usually suspicious Calcification according to size – coarse = benign, fine = suspicious Identify the imaging modality + organ Identify the imaging modalities + organ Identify the imaging modality + organ + pathology Thank You