Radiological imaging of thyroid diseases. - PowerPoint Presentation

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Radiological imaging of thyroid diseases.

PG STUDENT - DR. SAGAR M RAUL.

UNDER THE GUIDANCE OF

DR. RAJESH UMAP SIR,

ASSOCIATE PROFESSOR,

DEPT OF RADIOLOGY,

BJGMC AND SGH PUNE.

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HYPERPLASTIC

NODULAR

Iso/hyperechoichypoechoic-honeycoombThin peripheral haloPeri & intranodular vascula.

ADENOMAHyper/iso/hypoechoicThick peripheral haloSpoke wheel Appearance

LYMPHOMAElderNHLDyspnoea,DysphagiaHashimoto’s thyroditisHypoechoic nd lobular Hypovascular/chaotic vasc.encasement

METSHomogenous HypoechoicNo calcificationPrimary-Rcc/breast/Melanoma

CARCINOMA

PAPILARY3RD,7TH DecadePsammoma bodiesCervical LNHYPOECHOIC PUNCTATECALCIFICATIONDisorganisedhypervascularityCystic LN Mets

FOLLICULARHyperechoicThick irregular haloTortous vesselsHematogenous spreadToBone/lung/brain/liver

MEDULARY

Famillial

MEN type-2Calcitonnin LN METS-HIGHHYPOECHOICCOARSE CALCIFICA

ANAPLASTICElderAggressiveInvasion=muscles,vesselsWorst prognosis

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Normal ultrasound anatomy of thyroid

It is located anterior and lateral to trachea

below the level of thyroid cartilage and above the sternal notch. (infrahyoid compartment)DIVISION : RIGHT AND LEFT LOBES,ISTHMUSPYRAMIDAL LOBE (10-40 %)

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The superior thyroid Vessels are found at upper pole of each lobe and inferior thyroid vein is found at lower pole whereas the inferior thyroid artery is located posterior to lower third of each lobe.

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Anteriorly-Sternohyoid & omohyoid muscles,

As hypoechoic bands.

Lateral- Sternocleidomastoid

As large oval band Posterior- Longus colli muscle Recurrent laryngeal nerve & inferior thyroid artery pass in the angle between trachea, oesophagus & thyroid lobe.On longitudinal scans, recurrent laryngeal nerve & inferior thyroid artery may be seen as hypoechoic bands between the thyroid lobe & oesophagus on left , thyroid lobe & longus colli on right.

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NORMAL DIMENSIONS OF THYROID LOBES

A-P LENGTHNEWBORN 8-9mm 18-20mmINFANT 12-15mm 25mmADULT 13-18mm 40-60mmNormal Mean Thyroid Volume (LxWxTHICKNESSx0.52) :

MALE-UPTO 23gm IS NORMALFEMALE- UPTO 22gm IS NORMAL. Mean thickness of isthmus

– 4 to 6mmA-P diameter is most precise because relatively independent of possible dimensional asymemetry between two lobes.When AP diameter- > 2cm --- Enlarged gland.8

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EMBRYOLOGY

Thyroid gland is originated from epithelial cells of

floor of pharynx.

It descends from pharynx & remains connected to pharynx through a tract,known as thyroglossal duct.The gland reaches to its normal location by 7 weeks of gestational age.Then after duct involutes.

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CONGENITAL ABNORMALITIES

AGENESIS/HYPOPLASIA OF THYROID

ECTOPIC THYROID

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THYROID AGENESIS

USG : Abnormal

echogenic tissue in the expected location of the thyroid, without any normal flow on color Doppler imaging. There is no evidence of ectopic thyroid tissue.

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ECTOPIC THYROID

The thyroid gland develops as a median angle from a diverticulum of the foramen cecum.Normally, it descends to its typical location anterior to the cervical trachea via the thyroglossal duct. Anomalies of descent can lead to a lingual or sublingual

position of the gland.Nuclear medicine scintigraphy with sodium iodine-123 or pertechnetate-99m is used to evaluate the neck for the presence of thyroid tissue.Diagnosis of lingual thyroid is made when uptake is seen at the tongue base but not in the thyroid bed.

Further evaluation can be done using CT & MRI imaging.14

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CT image- round mass at tongue base which enhances after contrast administration.  A pertechnetate-99m scan shows uptake corresponding to mass at tongue base without uptake in the thyroid bed. 

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Thyroid disorders

Thyroid disorders can be divided into

Nodular thyroid disease

Diffuse thyroid disease.16

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Nodular thyroid disease

Hyperplasia and goiter

Adenoma

CarcinomaLymphomaMetastases

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Hyperplasia and Goiter:

Etiology:

Iodine deficiency, dishormonogenesis (familial),poor utilization of Iodine.

F:M-3:1 ,more between 35-50 years.When hyperplasia leads to an overall increase in size or volume of the gland it is called as GOITER.Hyperplastic nodules often undergo liquefactive

degeneration with the accumulation of blood, serous fluid and colloid substance, referred to as hyperplastic,adenomatous, or colloid nodules.Coarse and perinodular calcification occur.18

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HYPERPLASIA AND GOITER

Sonography

Most   hyper plastic or adenomatous nodules are

isoechoic compared to normal thyroid tissue.As Size of the mass increases, it may become hyperechoic.Less frequently hypo echoic sponge—like or honey coomb cystic pattern is seen.When nodule is hyperechoic or isoechoic, a thin peripheral hypoechoic halo is commonly seen-due to perinodular blood vessels and edema or compression of adjacent normal parenchyma.Perinodular, intranodular

vascularity on colour Doppler.DEGENERATIVE CHANGES:Purely anechoic -due to serous/colloid fluid.Echogenic fluid/moving fluid-fluid levels due to hemorrhage.Bright echogenic foci with comet tail artifacts due to

dense colloid material/microcrystals.Eggshell(thin peripheral) or coarse calcification.19

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Sagittal image of predominantly cystic nodule (calipers), which proved to be benign at cytologic examination.

Sagittal image of predominantly

solid nodule , which proved to be benign at cytologic examination.

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Transverse US images of mostly cystic thyroid nodule with a mural component containing flow. (a) Gray-scale image shows predominantly cystic nodule with small solid-appearing mural component

(b)

Addition of color Doppler mode demonstrates flow within mural component , confirming that it is tissue and not debris. US-guided FNA can be directed into this area. The lesion was benign at cytologic examination.

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FOLLICULAR ADENOMA

F:M – 7:1

Solitary or as a part of multi nodular goiter.

SonographyHyperechoic,

iso or hypoechoic solid masses .Have Peripheral hypoechoic halo which is thick & smooth- due to fibrous capsule and blood vessels.Typical spoke and wheel type of appearance on color

doppler.D/D : FOLLICULAR CARCINOMA— where vascular and capsular invasion are hallmarks.26

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FOLLICULAR ADENOMA

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Thyroid Carcinoma:

Papillary cancer

3

rd and 7th decade. F>MThe major route of spread is through lymphatics to nearby cervical lymph nodes.Distant metastasis is rare (2-3%) and occurs to mediastinum and lungs.

HISTOLOGY: PSAMMOMA BODIES31

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Sonography

Hypoechoic nodules with

microcalcifications

(tiny punctuate hyperechoic foci with or without acoustic shadowing). Disorganized hypervascularity on color doppler,Mostly in well encapsulated form. Cervical lymphnode metatasis which may contain tiny

punctate echogenic foci due to microcalcifications. Cystic lymph node metatasis in neck occur almost exclusively with papillary carcinoma.32

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Role of color Doppler US.

(a)

Transverse gray-scale image of Predominantly solid thyroid nodule (b) Addition of color Doppler modeshows marked internal vascularity,indicating increased likelihood that nodule is malignant. This was a papillary carcinoma.

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Malignant Benign

Punctate

echogenicities in thyroid nodules. (a) Sagittal US image of nodule containing multiple fine echogenicities with no comet-tail artifact. These are highly suggestive of malignancy.FNA and surgery confirmed papillary carcinoma. (b) Transverse US image of nodule containing cystic areas with punctate

echogenicities and comet-tail artifact consistent with colloid crystals in a benign nodule.

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Follicular variant of papillary ca of thyroid:-

10%

cases of Papillary Ca.

Similar to Follicular Ca on ultrasound and gross pathology.Microscopic studies show nuclear features of Papillary Ca.Clinical course and treatment are same as Papillary Ca.Papillary Microcarcinoma:-

Rare, non encapsulated sclerosing tumor measuring less than 1.0 cm.Pt present with enlarged cervical LN with palpably normal gland.Nodules have hyper echoic fibrotic patches with no visible micro calcifications.

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Follicular Carcinoma

5 -15%

of thyroid neoplasms.Hematogenous spread to bone/lung/brain/liver.Sonography

:Cant be differentiated from follicular adenomaSo treatment for both is surgical excision.Hypoechoic nodule with irregular tumor marginsThick, irregular halo.Tortuous or chaotic arrangement of internal blood vessels on color doppler.PATHOLOGY: Vascular & capsular invasion

.40WIDELY INVASIVE FORMMINIMALLY INVASIVE FORM-Not well encapsulated -Invasion of vessels and adjacent thyroid is more easily demonstrated.

-Metastasis is in 20-40% cases Well encapsulatedNo gross invasion seen. Only focal histologic invasion noted.5-10% cases.

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Medullary

Carcinoma

only 5 % thyroid cancer. Derived from parafollicular or C cells secretes calcitonin.- useful serum marker.Frequently familial and Associated with MEN II

syndrome.Bilateral in 90% of familial cases.High incidence of metastatic to lymphnodes.Sonography

- Similar to papillary carcinoma- hypoechoic solid mass with calcifications(often, but coarse than papillary carcinoma). -Local invasion and cervical lymphadenopathy are also more common.44

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Anaplastic

thyroid carcinoma

Occurs in elderly < 5% tumors WORST prognosis Presents as a rapidly enlarging mass extending beyond

gland and invading adjacent structures. Show aggressive local invasion of muscle and vessels. Sonography Hypoechoic masses often seen to

encase or invade blood vessel and neck muscles (CT or MRI demonstrates the tumor more accurately owing to their large size) . 48

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Aggressive thyroid cancer in left neck with spread to lungs

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Lymphoma

4%

of all thyroid malignancies.Mostly non-Hodgkin’s typeElder females In 70-80% cases arises from pre-existing chronic lymphocytic thyroiditis(HASHIMOTO’S thyroiditis) with subclinical or overt hypothyroidism. Sonography

Markedly Hypoechoic lobulated mass .Hypovascular or show blood vessels with chaotic distribution and arteriovenous shunts.Large areas of cystic necrosis may occur as well as encasement of adjacent neck vessels. Adjacent thyroid parenchyma heterogenous

due to associated chronic thyroiditis.51

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Isotope scan of thyroid demonstrating a photopenic area within the left lobe.

Axial contrast enhanced CT of the same patient shows a solid mass within left lobe of thyroid . Lymphoma was proven by biopsy.

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METASTASIS TO THYROID GLAND

RARE

THROUGH

HAEMATOGENOUS SPREADSOLITARY WELL CIRCUMSCRIBED HYPOECHOIC NODULES WITH OR WITHOUT CALCIFICATIONSMELANOMA (39%)BREAST CA (21%)RENAL CELL CA (10%)

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Differentiation

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Feature

Benign

malignant

Internal contents

Purely cystic

Cystic with thin septaeMixed solid and cysticComet tail artifact

++++

++++

+++

+++

+

+

++

+

Echogenicity

Hyperechoic

Isoechoic

Hypoechoic

++++

+++

+++

+

++

+++

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Feature

Benign

Malignant

Halo

Thin

Thick incomplete

++++

+

++

+++

Margins

Well definedPoorly defined

+++

++

++

+++

Calcification

Eggshell

Coarse calcification

Microcalcification

++++

+++

++

+

+

++++

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+ rare (<1%)++ low probability (<15%)

+++ intermediate probability(16 to 84%)

++++ high probability (>85%)

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Benign

Malignant

Doppler

Peripheral flow

Internal flow

+++++

++

+++

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HYPERPLASTIC

NODULAR

Iso/hyperechoichypoechoic-honeycoombThin peripheral haloPeri & intranodular vascula.

ADENOMAHyper/iso/hypoechoicThick peripheral haloSpoke wheel Appearance

LYMPHOMAElderNHLDyspnoea,DysphagiaHashimoto’s thyroditisHypoechoic nd lobular Hypovascular/chaotic vasc.encasement

METSHomogenous HypoechoicNo calcificationPrimary-Rcc/breast/Melanoma

CARCINOMA

PAPILARY3RD,7TH DecadePsammoma bodiesCervical LNHYPOECHOIC PUNCTATECALCIFICATIONDisorganisedhypervascularityCystic LN Mets

FOLLICULARHyperechoicThick irregular haloTortous vesselsHematogenous spreadToBone/lung/brain/liver

MEDULARY

Famillial

MEN type-2Calcitonnin LN METS-HIGHHYPOECHOICCOARSE CALCIFICA

ANAPLASTICElderAggressiveInvasion=muscles,vesselsWorst prognosis

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Evaluation of nodules incidentally detected by sonography

Nodules

<1.5cm

: follow up by palpation at time of next physical examinatonNodules > 1.5cm : evaluation usually by FNAAny nodule with malignant features like–microcalcifications, irregular margin , thick halo , or internal flow: FNA

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Indications for Biopsy guidance

Nonpalpable

suspected nodule with inconclusive physical examination.Patients at high risk of developing thyroid cancer, normal gland by physical examination but sonography demonstrates a nodule.Previous

non diagnostic / inconclusive biopsy. 61

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Diffuse Thyroid disease

Characterised

by

Generalized enlargement of gland and no palpable nodules.Diagnosis is usually based on clinical and laboratory finding and occasion by FNA. Sonography helpful when underlying disease causes asymmetric thyroid enlargement. Sonographic diagnosis of diffuse thyroid disease is made when isthmus may be up to 1 cm or more thickness.

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DIFFUSE THYROID DISEASE

1.THYROIDITIS

CHRONIC AUTOIMMUNE LYMPHOCYTIC THYROIDITS(HASHIMOTO’S THYROIDITIS)

SUBACUTE GRANULOMATOUS THYROIDITIS (DE QUERVAIN’S DISEASE)

ACUTE SUPPURATIVE THYROIDITIS2.ADENOMATOUS OR COLLOID GOITRE

3. GRAVE’S DISEASESILENT/PAINLESS THYROIDITIS

INVASIVE

FIBROUSTHYROIDITIS

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ACUTE SUPPURATIVE THYRODITIS

Rare inflammatory disease caused by bacteria affecting children.Sonography useful in selected cases to detect thyroid abscess.

Thyroid abscess: Ill defined hypoechoic heterogenous mass with internal debris +/-- septa and gas.

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SUBACUTE GRANULOMATOUS THYROIDITIS

(DE QUERVAIN’S)

Spontaneously remitting inflammatory disease probably caused by viral infection.C/F : fever, enlargement of gland ,Tenderness Sonography –

Enlarged hypoechoic gland with normal or decreased vascularity due to edema.

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Chronic autoimmune lymphocytic thyroiditis

.

(HASHIMOTO’S THYROIDITIS)

Most common thyroiditisYoung / middle aged woman F:M – 8 : 1 Painless diffuse enlargement of gland

Often a/w hypothyroidismAutoimmune – Antibodies against Thyroglobulin or TPO.

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Chronic autoimmune lymphocytic thyroiditis

.

(HASHIMOTO’S THYROIDITIS)

USG :- Diffuse enlarged coarsened parenchymal echotexture Usually more hypoechoic than normal gland Vascularity

: normal / decreased Occasionally hypervascular similar to thyroid inferno due to stimulation from high levels of TSH. Cervical LN present. In end stage, atrophy of gland heterogenous with absent blood flow.MICRONODULATION :- Multiple discrete

hypoechoic nodules of 1-6 mm size strongly s/o chronic thyroiditis. Lobules of thyroid parenchyma are infiltrated by lymphocytes.These lobules are surrounded by multiple linear echogenic fibrous septations giving PSEUDO-LOBULATED APPEARANCE.Both benign and malignant nodules coexist.Increased risk of B – cell malignant lymphoma of thyroid gland.FNA biopsy is helpful.

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Painless (silent) thyroiditis

Thyroid enlargement with hyperthyroidism occurs in early phase Followed by hypothyroidism.

Clinical findings are similar to subacute thyroiditis except tenderness Histologic and sonographic pattern of chronic autoimmune thyroiditis.Spontaneously remitts in 3-6 months

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MULTINODULAR GOITRE

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Graves disease

Diffuse abnormality of thyroid gland with associated

hyperfunction

(thyrotoxicosis ). SonographyDiffusely hypoechoic or inhomogenous

texture Color Doppler shows hypervascular pattern known as “thyroid inferno”. Spectral Doppler shows peak velocities exceeding 70cm/sec.

No correlation with hypervascularity and lab (hormone) levels.Significant decrease in flow velocities in thyroid vessels post treatment.75

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Graves disease.

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Graves′ disease, the thyroid usually

appears

moderately enlarged with hypoechoic

area inside.

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Graves’ disease – diffuse

hypervascularity

and peak systolic velocity of 80cm\sec

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Comparison between scans from the normal patient and a patient with Grave's disease. Note the overall increased uptake throughout the enlarged thyroid gland in the Grave's

patient.

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CT scans of the orbits show marked enlargement of the extra-ocular muscles with sparing of the tendons consistent with the ophthalmopathy seen with Grave's disease.

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Proptosis with enlargement of the eye muscles and compression of the optic nerve in the left eye.

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Voluminous

thickening of

all orbital muscles with

oedematous changes, pathognomonic for active Graves

’ orbitopathy with moderate to marked enhancement at the post-contrast study.

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Diagnosis Graves’ disease, Location(s) Eye, with gamuts Ocular muscles thickening

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Invasive fibrous

thyroiditis

(Riedel’s

struma)Female RareTends to progress to complete destructionUSG

Diffusely enlarged thyroid gland Inhomogenous parenchymal echo texture May have associated mediastinal or retroperitoneal fibrosis or sclerosing cholangitis

.D/D : From Anaplastic thyroid carcinoma….by biopsy.85

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Role of CT and MRI

in thyroid disorders

To demonstrate- Extent of local invasion - regional LN metastasisTo determine recurrence following Surgery.Detection of retrosternal & retrotracheal extension of the thyroid enlargement.Confirm the location of mass within the gland, evaluating nodal disease and assessing the airway.

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GOITER -Enhancing heterogenous

soft tissue mass

orignated

in thyroid and causing deviation of the trachea88

Large heterogenous soft tissue mass replacing the thyroid with speck of calcification,causing deviation of the trachea–medullary carci.

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Cystic metastasis from thyroid carcinoma

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CT signs suggesting the thyroid origin of

mediastinal

mass includeIntimate association of the superior pole of mass with thyroid gland & close proximity to the trachea.Hyperdensity of lesion compared to surrounding tissue.Presence of calcification.Persistent enhancement of the mass.

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Differentiation of benign and malignant primary thyroid masses is impossible on imaging, although the associated

lymphadenopathy

, vocal cord paralysis and bone or cartilage invasion obviously suggests malignancy.

MRI helps to differentiate scar from residual or recurrent tumor. Tumor - hypointense to isointense on T1WI iso

to hyperintense on T2WI scar - hypointense on both T1 and T2WI.91

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Role of radionuclide thyroid scintigraphy

To determine

functional status of the nodules

.Nodules may be cold, warm or hot depending on the uptake of tracer as compared to the normal thyroid tissue.Thyroid nodules concentrate less radioiodine (only 1%) than normal thyroid tissue hence appear cold.Most cold nodules are adenomas, colloid nodules or foci of thyroiditis or rarely intrathyroid lymphnodes, lymphoma or metastases.92

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Approximately 10 to 20 % of cold solitary thyroid nodules are malignant.Cold nodules further require FNAC or biopsy.

The demonstration of hot nodule on scintigraphy is not synonymous with autonomy, as it often represents spared focus of normal thyroid tissue in gland otherwise involved in destructive process.

The more important role is of 131 I whole body scintigraphy to identify

most functioning metastases, usually in the neck, lungs or bone, following total thyroidectomy.93

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TYPES USG RADIOACTIVE IODINE

UPTAKE

HASHIMOTO’S HYPOECHOIC

THYROIDITIS COARSENED VARIABLE

MICRONODULATION SUBACUTE HYPOECHOIC

GRANULOMATOUS N/HYPOVASCULAR DECREASED GRAVE’S DISEASE INHOMOGENOUS INCREASED HYPERVASCULAR

INVASIVE FIBROUS INHOMOGENOUS VARIABLE EXTRATHYROID INFLAMMATION VESSEL ENCASEMENT

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SONO ELASTOGRAPHY

Newer non invasive technique.

To diff b/w benign and malignant nodule.

Select a portion of nodule having nodule.Acquire two images – Before & After tissue compression.Freehand compression -minimize inter/intraobserver variability.ELASTICITY SCORE / PATTERN.1- WHOLE NODULE IS ELASTIC2- LARGE PART OF NODULE IS ELASTIC

3- PERIPHERAL PART OF NODULE IS ELASTIC4- UNIFORMLY ANELASTIC.

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Thank you