1. بسم الله الرحمن الرحيم

2. ROLE OF MRI IN ENT DISEASES BY PROF. Dr. YASSER ABDEL AZEEM M.D. PROF. OF RADIODIAGNOSIS AIN SHAMS UNIVERSITY

3. MR PHYSICS IN BRIEF  Non invasive imaging using hydrogen protons abundant in human body tissues  Placing the patient in a magnet and exposing him to various magnetic fields. This yields variations in the magnetic effect induced on protons.

4.  Computer softwares ------> image formation based on differences in magnetic relaxation properties basically the T1 & T2 differences - ----> this is highlighted by the used parameters ( mainly TR & TE ) that yield T1W or T2W images or other.  Sequence: the way we repeat our MR experiment to yield T1W, T2W, Proton density, Flair etc.

5.  Spin echo sequence (Basic sequence ) Good contrast Good contrast Relatively long time Now less than 5 minutes  Gradient echo sequence ( Fast sequence) Average contrast Fast scanning Used for MR angiography

6.  Inversion recovery sequence STIR--------------> Fat suppressed FLAIR------------> Water suppressed  Echo planar techniques for functional imaging DiffusionPerfusion Brain activation  MR cisternography Heavily T2W sequences emphasizing CSF

7.  Magnetization transfer technique Best for post contrast T1W images Best for post contrast T1W images  MR Spectroscopy Placing voxel or voxels over lesions to analyze the metabolic contents of lesions for characterization. Placing voxel or voxels over lesions to analyze the metabolic contents of lesions for characterization.  MR angiography techniques Time of flight Time of flight Phase contrast Phase contrast Contrast enhanced Contrast enhanced

8.  Bright signal on T1 spin echo - 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 echo - Fluid - Fluid - Most lesions - Most lesions - Metallic objects - Metallic objects - Calcification & Air - Calcification & Air - Cortical bone - Cortical bone

9.  Bright signals on T2 spin echo - Subacute blood - most lesions - Fluids - Melanin  Dark signals on T2 spin echo - Fat - Calcification - Chronic blood (hemosiderin) - Air

10. MAIN PATHOLOGIES WHERE MRI CAN HAVE A SIGNIFICANT ROLE 1.Skull base lesions difficult or impossible to view on endoscopies or by direct examination. for origin, extent, perineural spread, vascular affection, intracranial extension. Marrow invasion is best detected in non contrast T1W & fat suppressed sequences, occasionally, CT may detect early cortical erosion not detected by MR yet CT consistently underestimate the extent of neoplastic skull base involvement e.g. nasopharyngeal carcinoma & MR is the recommended study of choice Marrow invasion is best detected in non contrast T1W & fat suppressed sequences, occasionally, CT may detect early cortical erosion not detected by MR yet CT consistently underestimate the extent of neoplastic skull base involvement e.g. nasopharyngeal carcinoma & MR is the recommended study of choice

11. 2- Neck compartments lesions specially the deep ones, better characterize lesions than deep ones, better characterize lesions than CT scanning CT scanning

35. 3. Cerebellopontine angle & internal auditary canal lesions

43. 4 - Better visualization and staging of cancer larynx the issue of laryngeal cartilage invasion which upstages tumors to T4 precluding organ preservation therapy

51. 5- Metastatic nodal detection, non contrast MR images are slightly better than CT yet also depend on size criteria. Recently tissue specific MR contrast agent can differentiate metastatic from benign cervical adenopathies

55. 6- Potential problems or complaints tinnitus specially the pulsatile type and also to detect for reterocochlear causes of the deafness

56. Pulsatile tinnitus (subjective) 1-Benign increase ICP: usually female, obese, with headache, clinically she has papilledema, tinnitus. CT & MR  empty sella, slit like ventricles or normal. Cause: increased resistance to CSF absorption  interstitial brain edema  systolic CSF pulsations transmitted to dural sinuses  periodic compression of heir walls. Cause: increased resistance to CSF absorption  interstitial brain edema  systolic CSF pulsations transmitted to dural sinuses  periodic compression of heir walls. 2-Otosclerosis: osseous dysplasia of the inner ear where abnormal foci of vascular haversian bone replaces the normal otic capsule. Abnormal intraosseous anastomosis and inflammation are responsible for the tinnitus. 3-Paget’s disease of the temporal bone: as in otosclerosis, abnormal intraosseous anastomosis.

57. Pulsatile tinnitus (objective) 1-Vascular neoplasms: as glomus jugulare or glomus tympanicum tympanicum 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 AICA arterial loop of AICA 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.

62. 7- Congenital anomalies of the inner ear

63. 9- Better detection and characterization of the brain causes of ENT problems.

68. 9- Non invasive imaging of vascular lesions

70. 10- MR Spectroscopy has the potential to monitor surgical & radiotherapy or chemotherapy treatment & to identify early recurrent tumors of head & neck & differentiate them from post treatment changes by identifying the metabolic constituents of the lesion rather than depending on volume changes. Main indicator is the elevation of choline\creatinine ratio

72. 11- MR cisternography for CSF rhinorrhea & otorrhea otorrhea

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

76. THANK YOU