Clinical correlation and interpretation of Brain MRI by dr.Sagor
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How to correlate and interpret Brain MRI
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Clinical correlation and interpretation of Brain MRI by dr.Sagor
- 2. MAGNETIC RESONANCE IMAGING: Brain MRI - Interpretation & Clinical Correlation Dr. Md. Humayun Rashid MS Resident (Phase B, Year 2) Chittagong Medical College Hospital, Chattogram, Bangladesh
- 3. Table of contents Review of Basic Principle Basic steps of MRI interpretation Clinical correlation Interactive session Conclusion
- 4. “The value of experience is not in seeing much, but seeing wisely..” - Sir William Osler (1849-1919)
- 5. SEQUENCE OF MRI IMAGINGS T1WI T2WI FLAIR STIR DWI ADC GRE MRS Post-Gd images MRA MRV
- 9. Normal Anatomy of Brain MRI MRI is often incorrectly considered a superior imaging modality to other imaging techniques. In many circumstances, it is inferior to CT, ultrasound, or even plain X-ray. The successful application of MRI depends on the clinical question in mind, normal anatomical structure and pathological changes along with clinical scenario.
- 10. Fig. 1.1 Post Contrast Axial MR Image of the brain 1 2 3 4 5 Post Contrast sagittal M.R.I. Section at the level of Foramen Magnum Answers 1. Cisterna Magna 2. Cervical Cord 3. Nasopharynx 4. Mandible 5. Maxillary Sinus
- 11. Fig. 1.2 Post Contrast Axial MR Image of the brain 7 6 Post Contrast sagittal M.R.I. Section at the level of medulla Answers 6. Medulla 7. Sigmoid Sinus
- 12. Fig. 1.3 Post Contrast Axial MR Image of the brain 15 8 9 10 11 12 13 14 16 17 Post Contrast sagittal T1 Wtd M.R.I. Section at the level of Pons Answers 8. Cerebellar Hemisphere 9. Vermis 10. IV Ventricle 11. Pons 12. Basilar Artery 13. Internal Carotid Artery 14. Cavernous Sinus 15. Middle Cerebellar Peduncle 16. Internal Auditory Canal 17. Temporal Lobe
- 13. Fig. 1.4 Post Contrast Axial MR Image of the brain 18 19 20 21 22 Post Contrast sagittal M.R.I. Section at the level of Mid Brain Answers 18. Aqueduct of Sylvius 19. Midbrain 20. Orbits 21. Posterior Cerebral Artery 22. Middle Cerebral Artery
- 14. Fig. 1.5 Post Contrast Axial MR Image of the brain 23 24 25 26 27 Post Contrast sagittal T1 M.R.I. Section at the level of the III Ventricle Answers 23. Occipital Lobe 24. III Ventricle 25. Frontal Lobe 26. Temporal Lobe 27. Sylvian Fissure
- 15. Fig. 1.6 Post Contrast Axial MR Image of the brain 28 29 30 31 32 38 33 34 36 35 37 Post Contrast sagittal M.R.I. Section at the level of Thalamus Answers 28. Superior Sagittal Sinus 29. Occipital Lobe 30. Choroid Plexus within the occipital horn 31. Internal Cerebral Vein 32. Frontal Horn 33. Thalamus 34. Temporal Lobe 35. Internal Capsule 36. Putamen 37. Caudate Nucleus 38. Frontal Lobe
- 16. Fig. 1.7 Post Contrast Axial MR Image of the brain 39 40 41 Post Contrast sagittal M.R.I. Section at the level of Corpus Callosum Answers 39. Splenium of corpus callosum 40. Choroid plexus within the body of lateral ventricle 41. Genu of corpus callosum
- 17. Fig. 1.8 Post Contrast Axial MR Image of the brain 42 43 44 Post Contrast sagittal M.R.I. Section at the level of Body of Corpus Callosum Answers 42. Parietal Lobe 43. Body of the Corpus Callosum 44. Frontal Lobe
- 18. Fig. 1.9 Post Contrast Axial MR Image of the brain 45 46 Post Contrast sagittal M.R.I. Section above the Corpus Callosum Answers 45. Parietal Lobe 46. Frontal Lobe
- 22. We know from previous session: T1 W Images: Anatomy Sub-acute Hemorrhage Fat-containing structures T2 W Images: Edema Demyelination Infarction Chronic Hemorrhagecal Details
- 24. FLAIR Images: Edema, Demyelination Infarction esp. in Periventricular location
- 26. DWI & ADC:
- 27. GRE: Gradient Echo Imaging T2*
- 28. SWI:
- 30. MRI Protocols MRI protocols are a combination of various MRI sequences, designed to optimally assess a particular region of the body and / or pathological process. There are some general principles of protocol design for each area. However, the specifics of a protocol are dependent on MRI hardware and software, radiologist's and referrer's preference, patient factors (e.g. allergy) and time constraints.
- 31. MRI Protocols The implementation of a protocols has 3 chief purposes: maximizing diagnostic quality delivery of consistency in scan quality efficient and effective radiology service delivery
- 32. MRI Protocols MRI protocol: brain screen MRI protocol: brain tumour MRI protocol: stroke MRI protocol: brain infection MRI protocol: brain trauma MRI protocol: demyelinating diseases MRI protocol: epilepsy MRI protocol: neurodegenerative diseases MRI protocol: pituitary MRI protocol: CSF flow
- 33. MRI protocol: brain screen T1 weighted plane: sagittal (or volumetric 3D) sequence: fast-spin echo (T1 FSE) or gradient (T1) purpose: anatomical overview, which includes the soft tissues below the base of skull T2 weighted plane: axial sequence: T2 FSE purpose: evaluation of basal cisterns, ventricular system and subdural spaces, and good visualisation of flow voids in vessels
- 34. FLAIR plane: axial sequence: FLAIR purpose: assessment of white-matter disorders (e.g. chronic small vessel disease and demyelination diseases) diffusion weighted imaging (DWI) plane: axial sequence: DWI , ADC purpose: multiple possible purposes (from the identification of ischemic stroke to the assessment of active demyelination)
- 35. susceptibility weighted imaging (SWI) plane: axial sequence: susceptibility weighted imaging (ideal) or T2* purpose: identify blood products or calcification
- 36. MRI Protocol: Brain tumor: T1 T2 Flair DWI: Purpose: evaluation of the tumour cellularity. Post contrast sequence: plane: axial and coronal (at least two different planes)
- 37. susceptibility weighted imaging (SWI) purpose: identify blood products or calcification within the tumour When assessing gliomas it is relevant to include advanced MRI sequences, such as: perfusion purpose: elevation in rCBV is generally related with a high- grade tumour. It also helps in the evaluation f pseudoprogression and pseudoresponse spectroscopy purpose: metabolic peaks characterization to differentiate from non tumorous lesion.
- 38. MRS Magnetic resonance spectroscopy (MRS) is a means of noninvasive physiologic imaging of the brain that measures relative levels of various tissue metabolites Purcell and Bloch (1952) first detected NMR signals from magnetic dipoles of nuclei when placed in an external magnetic field. Initial in vivo brain spectroscopy studies were done in the early 1980s. Today MRS-in become a valuable physiologic imaging tool with wide clinical applicability.
- 39. Clinical Use of MRS Distinguish neoplastic from non neoplastic masses. Distinguish cerebral abcess from neoplastic masses. Primary from metastatic masses. Tumor recurrence vs radiation necrosis Prognostication of the disease Mark region for stereotactic biopsy. Monitoring response to treatment. Occasionally: Epilepsy Neurodegenerative disorders Multiple sclerosis Hepatic encephalopathy
- 42. Case Scenario Mr.Prodip Das, 60 years male hailing from satkania, chattogram with the complaints of headache for 2 months and gradual diminish of vision for 1.5 months with no neurological deficit.
- 45. Why Clinical Correlation? Although the MRI appearances provide information regarding the position and size of the areas of abnormality, it is the different clinical histories which provide the strongest clues to the diagnosis of neurological cases.
- 46. Patient 1: gradually worsening headaches and seizures – diagnosis = ? Patient 2: sudden onset left hemiplegia – diagnosis = ?
- 47. Case Scenario Mr.Sajal Shil, 35 years male presented with Headache for 2 weeks with gradual weakness in all extremities and altered level of consciousness.
- 50. Interactive Session on few clinical cases
- 57. 8 Years old Kaiser was admitted in our department with history of accidental injury to head. On examination, he had swelling in his left frontal region which was increasing in size gradually for last 6 months. What could be radiological diagnosis?
- 58. Meningiomas have characteristic imaging features and sites of origin, making diagnosis straightforward in most cases. However, meningiomas can be mimicked by other intracranial tumors and pseudo- tumors
- 64. Conclusion MRI is: Widely available Harmless to subject if proper safety precautions are used Still advancing in technology and applications Still in a growth phase for brain research
- 65. Take home message: Proper history, clinical examination, clinico-radiological correlation and sound knowledge on different MRI sequence is essential for proper diagnosis and management of neurosurgical patients.
- 66. Reference Diagnostic Imaging : Brain 3rd Edition by Anne G Osborn NEURORADIOLOGY: Key Differential Diagnoses and Clinical Questions 3rd Edition Bradley’s Neurology in clinical practice 6th Edition
Editor's Notes
- MRI is an imaging modality that uses non-ionizing radiation to create diagnostic useful images. MRI uses strong magnetic fields to align atomic nuclei (usually hydrogen protons) within body tissues, then uses a radio signal to disturb the axis of rotation of these nuclei and observes the radio frequency signal generated as the nuclei return to their baseline states.The radio signals are collected by small antennae, called coils, placed near the area of interest. These returning signals are converted into images by a computer attached to the scanner.
- T1WI: Tissue with short T1 relaxation time appears brighter (hyperintense) on T1WI. Tissue with long T2 relaxation time appears brighter (hyperintense) on T2WI.#Compartments filled with water (e.g. CSF) appears dark on T1WI.Compartments filled with water (e.g. CSF compartments) appear bright on T2WI. #Tissues with high fat content (e.g. white matter) appear bright on T1WI. Tissues with high fat content (e.g. white matter) appear less bright on T2WI. #T1WI is good for demonstrating anatomy. T2WI is good for demonstrating pathology since most (not all) lesions are associated with an increase in water content. FLAIR:Fluid-attenuation inversion recovery (FLAIR) sequence is used to eliminate the signal from CSF, which thus appears dark. It is useful for highlighting parenchymal lesions that lie close to ventricles or sulci like SAH, multiple sclerosis plaques, small cortical infarcts,meningitis or leptomeningeal carcinomatosis. DWI:is a way to display the molecular motion or diffusion of water protons within tissue. ADC: Apparent diffusion co efficient imaging: ADC is a measure of the rate of diffusion. True restricted diffusion will be bright on diffusion and low (dark) on ADC maps. Acute cerebral infarction with cytotoxic edema is the most commonly encountered pathologic process to restrict diffusion and can be seen as early as 30 minutes after ictus. Restricted diffusion can also be seen in other processes like pyogenic abscess, highly cellular tumor, epidermoid cyst, and Creutzfeldt-Jakob disease. Pathologies with vasogenic edema (most cases of PRES) typically do not cause restricted diffusion. GRE : Gradient Recalled Echo T2 weighted imaging STIR:Short tau inversion recovery sequence is used to eliminate signal from fat. This is useful in diagnosing fat containing lesions like lipoma and dermoid cyst. MRS:MRS provides metabolite/biochemical information about tissues. Contrast: The tesla (symbol T) is a unit of measurement of the strength of the magnetic field. One tesla is equal to one weber per square metre.The weber (symbol: Wb) is the SI unit of magnetic flux. A flux density of one Wb/m2 is one tesla.
- Time-of-flight (TOF) imaging is most commonly used for MRA. Signal in intracranial arteries is related to flow phenomenon, and thus no IV gadolinium is needed. TOF MRA can be performed by both 2D and 3D techniques.
- Contrast-enhanced MRA is often used to evaluate the neck vasculature. Contrast-enhanced intracranial MRA is useful in patients with stent and/or coils.
- MRV can be performed with 2D/3D TOF techniques, which do not need administration of IV gadolinium. Indication:Evaluation of thrombosis > Tumour of the cerebral venous sinus
- 1. Cisterna Magna 2. Cervical Cord 3. Nasopharynx 4. Mandible 5. Maxillary Sinus
- 6. Medulla 7. Sigmoid Sinus
- 8. Cerebellar Hemisphere 9. Vermis 10. IV Ventricle 11. Pons 12. Basilar Artery 13. Internal Carotid Artery 14. Cavernous Sinus 15. Middle Cerebellar Peduncle 16. Internal Auditory Canal 17. Temporal Lobe
- 18. Aqueduct of Sylvius 19. Midbrain 20. Orbits 21. Posterior Cerebral Artery 22. Middle Cerebral Artery
- 23. Occipital Lobe 24. III Ventricle 25. Frontal Lobe 26. Temporal Lobe 27. Sylvian Fissure
- 39. Splenium of corpus callosum 40. Choroid plexus within the body of lateral ventricle 41. Genu of corpus callosum
- 42. Parietal Lobe 43. Body of the Corpus Callosum 44. Frontal Lobe
- 45. Parietal Lobe 46. Frontal Lobe
- • High signal intensity at Acute , subacute and chronic stage on T2WI because of increment of fluid at infarction. • Iso-intensity at acute stage , iso- or slightly low intensity at subacute stage, low intensity at chronic stage on T1WI. • Flair and DWI sequences are more sensitive for detecting acute infarction.
- Fluid-attenuation inversion recovery (FLAIR) sequence is used to eliminate the signal from CSF, which thus appears dark. It is useful for highlighting parenchymal lesions that lie close to ventricles or sulci like SAH, multiple sclerosis plaques, small cortical infarcts,meningitis or leptomeningeal carcinomatosis.
- High signal seen on these images indicates a pathological process such as infection, tumour, or areas of demyelination – as in this patient with multiple sclerosis
- Diffusion Weighted Imaging (DWI) and Apparent Diffusion Coefficient (ADC) images are viewed together Areas of high signal on the DWI images and low signal on the ADC images indicate 'restricted diffusion' - an indicator of a pathological process of cell death such as infarction, cancer, or abscess formation Restricted diffusion in a wedge-shaped region of the brain (arrow) is a characteristic finding of a recent cerebral infarct. These images also show smaller areas of restricted diffusion due to recent lacunar infarcts. Apparent diffusion co efficient imaging: ADC is a measure of the rate of diffusion. True restricted diffusion will be bright on diffusion and low (dark) on ADC maps. Acute cerebral infarction with cytotoxic edema is the most commonly encountered pathologic process to restrict diffusion and can be seen as early as 30 minutes after ictus. Restricted diffusion can also be seen in other processes like pyogenic abscess, highly cellular tumor, epidermoid cyst, and Creutzfeldt-Jakob disease. Pathologies with vasogenic edema (most cases of PRES) typically do not cause restricted diffusion.
- GRE is sensitive to small amounts of blood breakdown products as well as calcium and metallic deposits, fat, and air. T2* images (pronounced ‘T2 star’ – also known as ‘gradient echo’ images) can be used to highlight the presence of blood products – such as in this cerebral haemangioma.
- Susceptibility-weighted imaging (SWI) is a very sensitive type of gradient echo MR sequence. The most common use of SWI is for the identification of small amounts of hemorrhage/blood product or calcium, both of which may be inapparent on other MR sequences. enhances the contrast of calcifications and hemosiderin deposits. Thus, SWI has supplemented the clinical diagnosis of neurological disorders (cranioencephalic trauma and harmful clots), hemorrhagic disorders (vascular malformation, cerebral infarction and neoplasias) and neuroinfectious conditions (neurotoxoplasmosis and neurocysticercosis)
- The pre-gadolinium image shows only an indistinct area of abnormality in the left cerebral hemisphere The post-gadolinium image of the brain shows a very well-defined area of enhancement – in this case due to a malignant brain tumour
- rCBV: Regional cerebral blood volume
- Cerebral infaction
- Patient 1: gradually worsening headaches and seizures – diagnosis = brain tumour Patient 2: sudden onset left hemiplegia – diagnosis = acute cerebral infarct
- MRI done on same day
- Diffuse axonal injury: A patient with a history of trauma with microhemorrhages involving the cerebral gray/ white matter junctions, corpus callosum, and the left middle cerebellar peduncle. There is restricted diffusion in the genu and splenium of the corpus callosum as well as the right corona radiata.
- Hypertension: Multiple cerebral microhemorrhages involving the deep gray nuclei, brainstem, and cerebellum in a patient with a history of hypertension. There also are periventricular T2 hyperintensity and bilateral deep gray nuclei lacunes.
- Hemorrhagic metastases (breast cancer): A patient with a history of malignancy with prominent foci of susceptibility, T1 hyperintensity, associated enhancement, and surrounding vasogenic edema.
- There is a 3-cm left parietal lesion with a thin, T2 hypointense peripheral rim, smooth enhancement, prominent surrounding edema, and central restricted diffusion. Of note, the ring of peripheral enhancement is slightly thicker toward its cortical margin. Dx: Abcess
- Metastasis: A 2.2-cm right cerebellar ring enhancing lesion without associated restricted diffusion is identified. Of note, there is an enhancing internal septation as well as irregularity, nodularity, and varying thickness of the enhancing wall.
- A 5-cm, heterogeneous right occipital mass demonstrates a thick and nodular rim of enhancement. No internal restricted diffusion is noted. However, DWI hyperintensity associated with the enhancing rim suggests hypercellularity. Subtle ependymal enhancement is noted along the walls of the temporal horn of the right lateral ventricle. Marked surrounding edema and mass effect are noted. Dx: Glioblastoma multiforme
- Sarcoidosis:Multifocal lobulated dural-based enhancing masses (white arrows, A, B, C) mimicking multiple meiningiomas (arrows, D).Note dural tail–like appearance adjacent to sarcoid masses (dark arrows, A, B)
- FIESTA: Fast imaging employing steady-state acquisition The images show a T2 heterogeneously hyperintense and avidly enhancing mass with cystic components in the CPA with mass effect on the adjacent right cerebellum, middle cerebellar peduncle, and the pons. The mass extends into and expands the internal auditory canal (IAC). Dx: Vestibular schwannoma with cystic components
- A predominantly cystic suprasellar mass with marked T2 hyperintensity and without associated restricted diffusion. A sagittal postcontrast fat-saturated image demonstrates an irregular, mildly thickened, and mildly nodular rim of enhancement. Close inspection of the axial CT image demonstrates a few associated peripheral punctuate calcifications that are most prominent anteriorly. Dx: Craniopharyngeoma
- A large mass remodels the superior clivus. The epicenter is in the sellar and suprasellar regions, with marked upward displacement of the optic chiasm (accounting for the patient’s visual disturbance). Tiny hyperintense cystic spaces are seen on T2-weighted images. There is mild enhancement. Dx: Pituitary macroadenoma
- An axial FLAIR image demonstrates central hyperintensity of the pons with sparing of the peripheral fibers. Diffusion-weighted MRI shows corresponding restricted diffusion. T1-weighted precontrast and postcontrast MRI discloses no corresponding enhancement. Dx; Pontine demyelination