الله الله بسم بسمالرحيم الرحيم الرحمن الرحمن

ROLE OF MRI IN ROLE OF MRI IN ENT DISEASESENT DISEASES

BYBY

PROF. Dr. YASSER ABDEL AZEEM M.D.PROF. Dr. YASSER ABDEL AZEEM M.D.PROF. OF RADIODIAGNOSISPROF. OF RADIODIAGNOSIS

AIN SHAMS UNIVERSITYAIN SHAMS UNIVERSITY

MR PHYSICS IN BRIEFMR PHYSICS IN BRIEF

Non invasive imaging using hydrogen Non invasive imaging using hydrogen protons abundant in human body tissuesprotons abundant in human body tissues

Placing the patient in a magnet and Placing the patient in a magnet and

exposing him to various magnetic fields. exposing him to various magnetic fields. This yields variations in the magnetic This yields variations in the magnetic effect induced on protons .effect induced on protons .

Computer softwares ------> image formation Computer softwares ------> image formation based on differences in magnetic relaxation based on differences in magnetic relaxation properties basically the T1 & T2 differences properties basically the T1 & T2 differences -----> this is highlighted by the used -----> this is highlighted by the used parameters ( mainly TR & TE ) that yield parameters ( mainly TR & TE ) that yield T1W or T2W images or other.T1W or T2W images or other.

Sequence: the way we repeat our MR Sequence: the way we repeat our MR experiment to yield T1W, T2W, Proton experiment to yield T1W, T2W, Proton density, Flair etc.density, Flair etc.

Spin echo sequenceSpin echo sequence ( (Basic sequence )Basic sequence )

Good contrastGood contrast

Relatively long timeRelatively long time

Now less than 5 minutesNow less than 5 minutes

Gradient echo sequenceGradient echo sequence ( Fast sequence)( Fast sequence)

Average contrastAverage contrast

Fast scanningFast scanning

Used for MR angiographyUsed for MR angiography

Inversion recovery sequenceInversion recovery sequence

STIR--------------> Fat suppressedSTIR--------------> Fat suppressed

FLAIR------------> Water suppressedFLAIR------------> Water suppressed

Echo planar techniques for functional imagingEcho planar techniques for functional imaging

DiffusionDiffusion

PerfusionPerfusion

Brain activationBrain activation

MR cisternographyMR cisternography

Heavily T2W sequences emphasizing CSF Heavily T2W sequences emphasizing CSF

Magnetization transfer techniqueMagnetization transfer technique Best for post contrast T1W imagesBest for post contrast T1W images

MR SpectroscopyMR Spectroscopy Placing voxel or voxels over lesions to Placing voxel or voxels over lesions to

analyze the metabolic contents of lesions for analyze the metabolic contents of lesions for characterization.characterization.

MR angiography techniquesMR angiography techniques Time of flightTime of flight Phase contrastPhase contrast Contrast enhancedContrast enhanced

Bright signal on T1 spin echoBright signal on T1 spin echo- Blood- Blood

- Fat including Bone marrow- Fat including Bone marrow

- Protenacious material - Protenacious material

- Melanin- Melanin

- Paramagnetic substances e.g. gadolinium - Paramagnetic substances e.g. gadolinium

Dark signal on T1 spin echoDark signal on T1 spin echo

- Fluid- Fluid

- Most lesions - Most lesions

- Metallic objects- Metallic objects

- Calcification & Air- Calcification & Air

- Cortical bone - Cortical bone

Bright signals on T2 spin echoBright signals on T2 spin echo- Subacute blood- Subacute blood

- most lesions- most lesions

- Fluids- Fluids

- Melanin- Melanin

Dark signals on T2 spin echoDark signals on T2 spin echo- Fat- Fat

- Calcification - Calcification

- Chronic blood (hemosiderin)- Chronic blood (hemosiderin)

- Air- Air

MAIN PATHOLOGIES WHERE MRI MAIN PATHOLOGIES WHERE MRI CAN HAVE A SIGNIFICANT ROLECAN HAVE A SIGNIFICANT ROLE

1.1. Skull base lesions difficult or impossible to Skull base lesions difficult or impossible to view on endoscopies or by direct examination. view on endoscopies or by direct examination. for origin, extent, perineural spread, vascular for origin, extent, perineural spread, vascular affection, intracranial extension. affection, intracranial extension.

Marrow invasion is best detected in non Marrow invasion is best detected in non contrast T1W & fat suppressed sequences, contrast T1W & fat suppressed sequences, occasionally , CT may detect early cortical occasionally , CT may detect early cortical erosion not detected by MR yet CT consistently erosion not detected by MR yet CT consistently underestimate the extent of neoplastic skull underestimate the extent of neoplastic skull base involvement e.g. nasopharyngeal base involvement e.g. nasopharyngeal carcinoma & MR is the recommended study of carcinoma & MR is the recommended study of choicechoice

2- Neck compartments lesions specially the 2- Neck compartments lesions specially the

deep ones , better characterize lesions than deep ones , better characterize lesions than

CT scanning CT scanning

3. Cerebellopontine angle & internal auditary 3. Cerebellopontine angle & internal auditary canal lesions canal lesions

4 - Better visualization and staging of cancer 4 - Better visualization and staging of cancer larynx the issue of laryngeal cartilage larynx the issue of laryngeal cartilage invasion which upstages tumors to T4 invasion which upstages tumors to T4 precluding organ preservation therapyprecluding organ preservation therapy

5- Metastatic nodal detection, non contrast MR 5- Metastatic nodal detection, non contrast MR images are slightly better than CT yet also images are slightly better than CT yet also depend on size criteria. Recently tissue depend on size criteria. Recently tissue specific MR contrast agent can differentiate specific MR contrast agent can differentiate metastatic from benign cervical metastatic from benign cervical adenopathiesadenopathies

6- Potential problems or complaints tinnitus 6- Potential problems or complaints tinnitus specially the pulsatile type and also to detect specially the pulsatile type and also to detect for reterocochlear causes of the deafnessfor reterocochlear causes of the deafness

Pulsatile tinnitus (subjectivePulsatile tinnitus (subjective))

1-Benign increase ICP: usually female, obese, with 1-Benign increase ICP: usually female, obese, with headache, clinically she has papilledema, tinnitus. headache, clinically she has papilledema, tinnitus. CT & MRCT & MR empty sella, slit like ventricles or empty sella, slit like ventricles or normal.normal.

Cause: increased resistance to CSF absorption Cause: increased resistance to CSF absorption interstitial brain edema interstitial brain edema systolic CSF pulsations systolic CSF pulsations transmitted to dural sinuses transmitted to dural sinuses periodic periodic compression of heir walls.compression of heir walls.

2-Otosclerosis: osseous dysplasia of the inner ear where 2-Otosclerosis: osseous dysplasia of the inner ear where abnormal foci of vascular haversian bone replaces abnormal foci of vascular haversian bone replaces the normal otic capsule. Abnormal intraosseous the normal otic capsule. Abnormal intraosseous anastomosis and inflammation are responsible for anastomosis and inflammation are responsible for the tinnitus.the tinnitus.

3-Paget’s disease of the temporal bone: as in otosclerosis, 3-Paget’s disease of the temporal bone: as in otosclerosis, abnormal intraosseous anastomosis.abnormal intraosseous anastomosis.

Pulsatile tinnitus (objective)Pulsatile tinnitus (objective)1-Vascular neoplasms: as glomus jugulare or glomus 1-Vascular neoplasms: as glomus jugulare or glomus

tympanicumtympanicum

2-Congenital vascular anomalies: as aberrant or 2-Congenital vascular anomalies: as aberrant or dehiscent internal carotid artery, dehiscent dehiscent internal carotid artery, dehiscent jugular vein, high jugular bulb, redundant jugular vein, high jugular bulb, redundant arterial loop of AICAarterial loop of AICA

3-Vascular malformations: dural AVM or AVF, pial 3-Vascular malformations: dural AVM or AVF, pial (parenchymal) AVM.(parenchymal) AVM.

4-Other vascular abnormalities: intracranial aneurysm, 4-Other vascular abnormalities: intracranial aneurysm, atherosclerotic carotid artery disease, atherosclerotic carotid artery disease,

fibromuscular dysplasia of ICA, carotid artery fibromuscular dysplasia of ICA, carotid artery dissection. dissection.

7- Congenital anomalies of the inner ear 7- Congenital anomalies of the inner ear

9- Better detection and characterization of 9- Better detection and characterization of the brain causes of ENT problems.the brain causes of ENT problems.

9- Non invasive imaging of vascular lesions9- Non invasive imaging of vascular lesions

10-10- MR Spectroscopy has the potential to MR Spectroscopy has the potential to monitor surgical & radiotherapy or monitor surgical & radiotherapy or chemotherapy treatment & to identify early chemotherapy treatment & to identify early recurrent tumors of head & neck & recurrent tumors of head & neck & differentiate them from post treatment differentiate them from post treatment changes by identifying the metabolic changes by identifying the metabolic constituents of the lesion rather than constituents of the lesion rather than depending on volume changes. Main indicator depending on volume changes. Main indicator is the elevation of choline\creatinine ratio is the elevation of choline\creatinine ratio

11- MR cisternography for CSF rhinorrhea & 11- MR cisternography for CSF rhinorrhea &

otorrheaotorrhea

CONCLUSIONCONCLUSION

Full history & detailed clinical data are Full history & detailed clinical data are essential for the radiologist to tailor this essential for the radiologist to tailor this MR study & to add other modalities if MR study & to add other modalities if neededneeded

THANK YOUTHANK YOU