Showing posts with label Spine-Neuro MRI Protocols. Show all posts
Showing posts with label Spine-Neuro MRI Protocols. Show all posts

Inflammatory Spine / Centocor Spine (Ankylosing Spondylitis) MRI Protocol


"Inflammatory Spine / Centocor Spine (Ankylosing Spondylitis) MRI Protocol"
(coverage cerebellum to entire sacrum)

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  • T1 – 3 Plane Loc (Upper and Lower full spine loc)
  • Sag FSE T1 – upper and lower 
  • Sag FSE-IR – upper and lower 
  • Cor Obl FSE-IR (sacrum)
  • Cor Obl T1 (sacrum)
  • Axial T2 fat sat respective to the lesion

Post Contrast 
  • T1 Fat Sat (plane according to the lesion)
Technical Notes for "Inflammatory Spine / Centocor Spine (Ankylosing Spondylitis) MRI Protocol"

  • T1 Sag assessment of chronic spinal lesions, such as erosions and syndesmophytes 
  • STIR sag technique is able to visualize acute spinal lesions by depiction of bone marrow oedema caused by inflammation and hypervascularization
  • T1 post gad with fat saturation after application of gadolinium- allows for assessment of acute spinal lesions by depicting enhancement of Gd-DTPA as a sign of hypervascularization due to spinal inflammation
  • Oedematous lesions can be optimized by removing the surrounding high signal of fat, either by suppression [Short Tau Inversion Recovery sequences (STIR)] or by saturation (application of an additional pulse to saturate the protons of fat), which can be applied to T2W or T1W sequences post-gadolinium. 
Fig. 2
Inflammatory posterior element lesions on STIR MRI sequences in axial-SpA. (A) Posterior element/costovertebral T12 (arrow) lesion. (B) Superior facet lesion of T6 (arrowhead) and grade 1 endplate lesion (arrow) inferior endplate T3.

Protocol for 3T MR imaging sequences used for MRN of the sciatic nerve



Typical protocol for 3T MR imaging sequences used for MRN of the sciatic nerve

SequenceFOV (cm)In-Plane Resolution (mm)TR/TE (ms)Turbo Factor
Coronal T1 TSE30–404780/103
Coronal T2 3D SPACE30–4011600/128151
Coronal STIR 3D SPACE30–4011500/9141
Axial T2 SPAIR TSE35–40 LR × 20 AP34000/7517
Axial T1 TSE35–40 LR × 20 AP3800/116
  • All sequences were run with a high-resolution matrix (256 × 392 or higher).

Protocol for 3T MR imaging sequences used for MRN of the sciatic nerve

MRI protocol for Neurography


High-resolution peripheral nerve imaging requires careful consideration of coil selection, pulse sequence, method of fat suppression, section thickness, and field of view (6). Successful identification of subtle nerve abnormalities by use of MR neurography requires that the imaging parameters be optimized to maximize the signal-to-noise ratio, that spatial and contrast resolution sufficient to permit accurate delineation of fascicular morphology and nerve signal intensity be produced, and that a reasonable imaging time be maintained.Pelvic phase-array coils provide satisfactory coverage of the lumbosacral plexus but are inadequate for examining the sciatic nerve in most patients.

 We used to do in our 1.5 T avanto,4- to 7-mm section thickness, 0-mm intersection gap, 18- to 24-cm field of view, 256 × 192 to 256 matrix, and an 8- to 10-minute imaging time per sequence.

The sequences(high-resolution) mainly used in "MRI protocol for Neurography"
  • Coronal T1 SE
  • Coronal T2 FSE Fat Sat  or STIR 
  • Axial T1 SE
  • Axial T2 FSE Fat Sat  or STIR 
  • Sagital T1 SE
  • Sagital T2 FSE Fat Sat  or STIR 


Post Contrast "MRI protocol for Neurography"
  • T1 Fat sat Spin Echo Coronal
  • T1 Fat sat Spin Echo Axial
  • T1 Fat sat Spin Echo Sagital(Optional)

Technical notes "MRI protocol for Neurography"
  • Coronal/Axial  imaging coverage from L3 through the ischial tuberosity centered in the midline the sacral ala through the ischial tuberosity 
  • Sagital imaging coverage from the sacral ala through the ischial tuberosity 
  • T1-weighted imaging is used to define the bony structures and tissue planes surrounding the nerves
  • T2-weighted or fast spin-echo inversion recovery images, the normal sciatic nerve is slightly hyperintense to adjacent muscle and hypointense to regional vessels, with clearly defined fascicles separated by interposed lower signal connective tissue
  • The normal sciatic nerve  is a well-defined oval structure with discrete fascicles isointense to adjacent muscle tissue on T1-weighted images
  • Suppress the normal high signal intensity of fat to make the nerves more conspicuous
fig 1.



Necessary Scan Coverage of the MR Neurography



Because MR neurography sequences are relatively lengthy and motion sensitive, it is not generally feasible to screen the whole extremity from nerve root to sciatic bifurcation in one sitting. Department scheduling constraints and limited patient tolerance for prolonged MR imaging generally limit imaging time to approximately 1 hour. Therefore, it is imperative to prospectively determine the most likely level of the abnormality before initiating imaging, using all available clinical and electrophysiological information. For most of the patients, the abnormality was clinically localized using pain distribution, presence of a palpable mass, and/or motor or sensory deficits to determine the necessary coverage. Where available, electrophysiological studies, including electromyography and nerve conduction velocity studies, were used to limit the area examined. If electrophysiological studies were unavailable and the physical examination could not localize the abnormality to either the lumbosacral plexus or sciatic nerve, imaging was initiated proximally at the lumbosacral plexus and continued distally into the thigh by using multiple stations through the tibioperoneal bifurcation or until the causative abnormality was revealed.

fig 1.

Understanding the relevant lumbosacral plexus and sciatic nerve anatomy is crucial for the correct interpretation of MR neurographic studies. The lumbar plexus is composed of the ventral rami of L1 through L4 and is anatomically located behind the psoas muscle . A minor branch of L4 combines with the ventral ramus of L5 to form the lumbosacral cord or trunk . The lumbosacral trunk descends over the sacral ala and combines with the ventral rami of S1, S2, and S3 (and a branch of S4 to form the sacral plexus. The individual sacral plexus neural components coalesce and diverge along the ventral piriformis muscle surface, making it the key anatomic landmark for locating the sacral plexus and sciatic nerve. The sciatic nerve originates from the upper division of the sacral plexus at the inferior piriformis muscle border, and exits the pelvis through the greater sciatic foramen . The sciatic nerve gives rise to the tibial and common peroneal nerves, two anatomically and functionally distinct nerves that travel together in the thigh as the sciatic nerve. In most patients, the sciatic nerve bifurcates just above the knee into separate common peroneal and tibial nerves.

Segments of the Internal Carotid Artery



Segments of the Internal Carotid Artery

Limitations of the MRI Brain



  • Limited ability in imaging the skull and facial bones -- conventional X-ray or CT scan is better in demonstrating bone details.
  • Compared to CT scanning, MRI is less sensitive in demonstrating acute hemorrhage, as in subarachnoid hemorrhage and hemorrhagic infarction.
  • Hard to depict calcifications
  • MRI does not always distinguish tumor tissue from edema fluid
  • Less sensitive in detecting small abnormalities compared to CT scans (poor spatial resolution)
  • Inability to scan critically-ill patients requiring life support systems and monitoring devices that employ ferromagnetic materials.
  • May be dangerous in scanning patients with metal implants and other metal objects
  • May provoke claustrophobia
  • Longer exam time compared to CT scans
  • Safety in scanning pregnant women is not known. 

Cerebral Abscess MRI Protocol

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Plain "Cerebral Abscess MRI Protocol"
  • T1-Sagittal head
  • T1 SE-Axial head
  • FLAIR Axial head
  • T2 FSE Axial head
  • DWI/ADC
Post Contrast "Cerebral Abscess MRI Protocol"
  • T1 SE-Axial post-gadolinium (This is essentially the same sequence as the pre-gadolinium scan, but can be performed with the addition of a flow compensation (FC) pulse to better delineate the cerebral vessels, and a magnetization transfer (MT) pulse to optimize enhancing lesion detection.)
  • T1-coronal post-gadolinium head
  • MR perfusion
  • MR spectroscopy  
Radiology notes:"Cerebral Abscess MRI Protocol"

MR perfusion : rCBV is reduced in the surrounding oedema c.f. to both normal white matter and tumour oedema seen in high grade gliomas .

MR spectroscopy : elevation of a succinate peak is relatively specific but not present in all abscesses ; high lactate, acetate, alanine, valine, leucine, and isoleucine levels peak may be present ; Cho / Crn and NAA peaks are reduced.Magnetic resonance (MR) spectroscopy may be helpful in the differential diagnosis of toxoplasmosis versus CNS lymphoma. CNS lymphoma generally shows a mild pattern of elevated lipid and lactate peaks, with a prominent choline peak with some other normal metabolites. In toxoplasmosis, there are elevated lipid and lactate peaks, while other normal brain metabolites are nearly absent.


Diffusion-weighted MRI may be useful in differentiating abscess MRI features from necrotic tumor. 



Brain Abscess MRI findings Classification



  • Early cerebritis stage-The early cerebritis stage presents as an ill-defined subcortical hyperintense zone that can be noted on T2-weighted imaging. Contrast-enhanced T1-weighted studies demonstrate poorly delineated enhancing areas within the isointense to mildly hypointense edematous region.
  • Late cerebritis stage-During the late cerebritis stage, the central necrotic area is hyperintense to brain tissue on proton-density and T2-weighted sequences. Peripheral edema is common. The rim enhances intensely following contrast administration. Satellite lesions may be demonstrated.
  • Early and late capsule stages-During the early and late capsule stages, the collagenous abscess capsule is visible prior to contrast as a comparatively thin-walled, isointense to slightly hyperintense ring that becomes hypointense on T2-weighted MRIs.Diffusion-weighted imaging aids in depiction of specific features of a brain abscess. If a cerebral abscess ruptures into the ventricular system, diffusion-weighted images demonstrate specific patterns.Purulent material within the ventricle appears similar to that of the central abscess cavity, with a strongly hyperintense signal on diffusion-weighted images.
MRI Features in different Stages
  • Early cerebritis: swollen, edematous, areas of necrosis, ill-define margins; nonspecific (tumor, infarct)
  • Late cerebritis: increased central necrosis, thick irregular contrast enhancement, high on FLAIR, T2, and DWI
  • Early capsule: within 2 weeks, walled off capsule, necrotic center, enhancing rim
  • Late capsule: more defined rim, multiloculated, capsule is low on T2, markedly high on DWI





  • Pediatric Stroke MRI Protocol

    Stroke is a serious condition that affects 25 in 100,000 newborns and 12 in 100,000 children under 18 years of age. It is the sixth leading cause of death in children. There are three types of stroke: arterial ischemic stroke, sinovenous thrombosis, and intracranial hemorrhage. 
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    Acute "Pediatric Stroke MRI "
    • DWI in three planes and calculated ADC map
    • Coronal FLAIR
    • Axial T2-W FSE
    • Sagittal T1-W SE
    • Intracerebral 3-D TOF MRA
    • Axial dual-echo STIR and T1-W spin-echo through the neck
    • Extracerebral 2-D TOF MRA of the neck down to the aortic root

    Non-acute "Pediatric Stroke MRI" 
    • Acute stroke protocol without imaging of the neck

    Teaching points of "Pediatric Stroke MRI" 
    The aims of conventional MRI are not only to detect the infarct, but also to provide information to establish the cause of the stroke and to exclude other causes (such as tumour or infection). The majority of children with stroke have a combination of risk factors including sickle cell disease, congenital heart disease, anaemia, prothrombotic disorders and infections such as varicella-zoster . The rationale for the inclusion of intracranial MRA in all children with stroke is that cerebral arteriopathy is found in up to 80% of these children and most commonly affects focal areas of large intracranial arteries . Specific entities such as moyamoya disease may also be diagnosed. The commonest abnormality identified is occlusion or stenosis, of unknown aetiology, affecting the terminal internal carotid artery (ICA) or proximal middle cerebral artery (MCA).

    Extracranial MRA and, either a dual-echo STIR or fat-saturated axial T1-W imaging, through the neck can detect arterial dissection, particularly in children with posterior circulation infarcts . The inversion time of the STIR sequence is selected to suppress the fat within the neck. The fat saturation provided by both these sequences improves the conspicuity of the haematoma within the extracranial vessel wall.

    A 3-D TOF MRA sequence is used for the imaging of the intracranial vessels and a 2-D TOF MRA sequence for the extracranial vessels. The TOF scan times are shorter than phase-contrast (PC) MRA and there is lack of dependence on the choice of correct velocity encoding with obvious advantages when scanning ill children. Intracranial 3-D TOF MRA is also included in the investigation of children with IPH, although its sensitivity to T1 shortening may obscure the underlying abnormality .

    As CT is often the first-line investigation in children with stroke, the potential of DWI to detect hyperacute cerebral infarction prior to changes on T2-W MRI is not realized. However, inpatients (e.g. cardiac patients, patients with recent-onset stroke) can be imaged early, and in these children DWI can be used to detect infarcts of different ages.

    a | The MRI reveals a small acute stroke that shows restriction on diffusion-weighted imaging in the periventricular region (arrow). b | The corresponding apparent diffusion coefficient map confirms the occurrence of acute ischemia (arrow). c | The perfusion-weighted image shows a large area of hypoperfusion—basically the entire left middle cerebral artery territory (arrows)—representing diffusion–perfusion mismatch. d | This stroke was caused by embolization of a cardiac thrombus that led to partial occlusion of the internal carotid artery—little flow is seen on magnetic resonance angiography (arrow)—and complete occlusion of the middle cerebral artery (arrowhead).







    Meningitis MRI Protocol


    Plain "MRI Protocol for Meningitis"
    Sag T1
    Ax T1
    Ax T2 FSE/TSE
    Ax FLAIR FSE/TSE
    Ax DWI / ADC / B0
    Cor T2 FSE/TSE

    Post Contrast "MRI Protocol for Meningitis"
     T1 Axial
     T1 Coronal
     FLAIR Axial

    "MRI Protocol for Meningitis" Technical Notes
    • Coronal and sagittal thin-section, heavily T2-weighted MRIs may show CSF leaks, which may be the source of infection in cases of recurrent meningitis.
    • Plain and contrast-enhanced MRIs help to depict the complications of meningitis. Such complications include empyema/effusion, cerebritis/abscess, venous thrombosis, venous and arterial infarcts, ventriculitis, hydrocephalus, and edema (with or without cerebral herniation). 
    • The imaging features of meningitis are non-specific, demonstrating abnormal meningeal enhancement. MRI is superior to CT in the evaluation of patients with suspected meningitis 
    •  Add FLAIR post gad in suspected meningeal disease.
    •  For brainstem and midline lesions get sagittal post gad instead of coronal.
    •  For pineal lesions add thin sagittal T2 and T1 pre and post gad images.
    •  Single voxel spectroscopy (TE 35 and 144) on all new mass lesions
    •  Multi voxel only on suspected gliomas. For follow-up use TE 144.
    CT22MeningitisCT23Meningitis
     T1 weighted pre and post-contrast MRI's demonstrate non-specific abnormal meningeal enhancement.











    MRI features of Cerebral Abscess



    MRI is more sensitive and especially with the addition MRS and DWI far more specific for the diagnosis of cerebral abscesses. 

    T1 "MRI features of Cerebral Abscess"

    • central low intensity (hyperintense to CSF)
    • peripheral low intensity (vasogenic oedema) 
    • ring enhancement 
    • ventriculitis may be present, in which case hydrocephalus will commonly also be seen

    T2 / FLAIR "MRI features of Cerebral Abscess"

    • central high intensity (hypointense to CSF, does not attenuate on FLAIR)
    • peripheral high intensity (vasogenic oedema)
    • the abscess capsule may be visible as a intermediate to slightly low signal thin rim 1.

    DWI / ADC "MRI features of Cerebral Abscess"

    • high DWI signal is usually present centrally
    • often this represents true restricted diffusion (low signal on ADC)
    • peripheral or patchy restricted diffusion may also be seen; this finding is however not as constant as one may think, with up to half of rim enhancing lesions demonstrating some restriction not proving to be abscesses 2.  
    • in many instances high DWI are associated with high ADC signal, consistent with T2 shine through of the central necrotic portion

    MR perfusion : rCBV is reduced in the surrounding oedema c.f. to both normal white matter and tumour oedema seen in high grade gliomas 2.
    MR spectroscopy : elevation of a succinate peak is relatively specific but not present in all abscesses ; high lactate, acetate, alanine, valine, leucine, and isoleucine levels peak may be present ; Cho / Crn and NAA peaks are reduced.

    Imaging of Cerebral Abscess by MRI Perfusion


    pMRI can help in differentiating abscess from necrotic neoplasm.This is a rapid acquisition with moderate spatial resolution that can yield information on the entire brain and multiple lesions, even in agitated patients. 
    This sequence must be the first sequence performed after the gadolinium injection, and is acquired dynamically. After a baseline brain image acquisition is performed, an injection time of <8 sec is used to deliver 0.2 mmol/kg gadolinium chelate with a 10 ml normal saline bolus flush via the injector. This step may be performed by hand, but timing of the sequence is problematic. 
    Perform image analysis visually or off-line on a workstation using commercially available programs. 
    Regional cerebral blood volume (rCBV) maps can be reconstructed using an appropriate analysis of the MR signal intensity as a function of time. 
    The rCBV maps can be aligned with the anatomic images to obtain region-of-interest (ROI) data. 

      Fig. 1A.   Fig. 1B.

    Pediatric Pituitary MRI Protocol with & without contrast

    Without Contrast "Pediatric Pituitary MRI"

    • T1 Sagital 3mm
    • T1 Coronal 3mm
    • T2 Coronal 3mm
    • T1 Axial 5mm (Occasionally according to the lesion T2 Axial 5mm also used) 
    • T1 weighted three-dimensional gradient echo MRI technique (FSPGR)
    Post Contrast "Pediatric Pituitary MRI"
    • T1 weighted three-dimensional gradient echo MRI technique (FSPGR)
    • T1 Sagital 3mm
    • T1 Coronal 2mm
    Technical notes for "Pediatric Pituitary MRI"

    • In "Pediatric Pituitary MRI" we used to do all the sequences Spin Echo.
    • The anterior and posterior portions of the gland were not measured separately, because the small size of the gland and the relative isointensity of the two portions of the gland in a large number of infants precluded separate measurements of these structures.
    • The T1-weighted sagittal sequence was used to measure both the anteroposterior diameter and the height.
    • The width was measured from either axial or coronal images
    • ACTH producing pituitary adenomas are the most common cause of Cushing's Syndrome in childhood. Although Gadolinium-DTPA (Gd) enhanced T1 weighted spin echo magnetic resonance imaging (SE-MRI) has proven to be the most sensitive imaging modality for localizing pituitary adenomas, its diagnostic accuracy does not exceed 40-50% in detecting Cushing's disease (CD)

    MRI Pediatric Spine Protocol


    "MRI Pediatric Spine Protocol"
    • Sagittal T1 FSE
    • Sagittal T2 FSE
    • Axial T1 FSE
    • Axial T2 FSE
    •  (Coronal T1-W spin-echo for scoliosis)
     "MRI Pediatric Spine Protocol" with contrast enhancement  
    • Sagittal T1 FSE
    • Sagittal T2 FSE
    • Axial T2 FSE
    Contrast-enhanced "MRI Pediatric Spine Protocol"
    • Sagittal T1FSE
    • Axial T1 FSE  through target area

    Pediatric Brain with Contrast MRI Protocol



    • SAG T1 SE 3/5mm
    • AXIAL T2 SE 3/5mm
    • AXIAL FLAIR 3/5mm
    • CORONAL T2 FSE 4mm/FLAIR 4mm
    • DWI in three planes and calculated ADC map
    • AXIAL T1  SE 4mm
    POST CONTRAST "PEDIATRIC BRAIN MRI"
    • AXIAL T1 POST SE 4mm
    • COR T1 POST SE 4mm
    Optional "Pediatric Brain with Contrast MRI" Sequences
    • T2 Gradient (trauma and vascular malformations)
    • Dual-echo axial STIR sequence (children under 2years )
    TECHNICAL NOTES: "Pediatric Brain with Contrast MRI Protocol"
    • MR sequences may disturb the sleeping infant or child and ear protection such as earplugs and baby earmuffs should be used. 
    • Some motion can be avoided by swaddling infants, keeping them warm, and by placing moulded foam or airbags around the baby’s or child’s head.
    • Optimizing imaging of infants requires adjustment of contrast and resolution parameters.
    • The high heart rates of small children lead to more flow artifacts compared to adults. Note that the number of packages affects flow artifacts in FLAIR. Dividing FLAIR scans into more packages reduces flow sensitivity. It costs more scan time, but reduces the potential for misinterpretation of images.
    • DWI is acquired in all children unless artefacts from, for example, dental braces or a ventriculoperitoneal shunt, preclude it, and an ADC is calculated using automated computer software and provided for reporting.
    • In some cases, a T2*-W gradient-echo (GE) sequence (“susceptibility-weighted” sequence), sensitive to changes in local field inhomogeneity caused by the breakdown products of haemoglobin, is added. The sequence is particularly useful in trauma and vascular malformations such as multiple cavernomas.

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    Indications for Pediatric Brain MRI contrast medium administration



    Acute inflammation  

    •  Acute disseminated encephalomyelitis (ADEM)
    •  Optic neuritis

    Acute infection

    •  Abscess
    •  Cerebritis
    •  Discitis
    •  Empyema
    •  Encephalitis
    •  Meningitis
    •  Transverse myelitis

    Neurocutaneous disorders  
    • Congenital melanocytic naevus
    •  Neurofibromatosis type II
    Tumours  
    •  Benign and malignant
    •  Intracranial
    •  Intraspinal
    White matter disorders
    Vascular anomalies  
    •  Cavernomas
    •  Developmental venous anomalies
    Vascular disorders

    Acute Stroke MRI Protocol

    Without contrast "Acute Stroke MRI Protocol"

    •  3-Plane loc
    • Axial Diffusion
    • Axial EPI GRE
    • Axial EPI Flair T2
    • Axial 2D TOF (coarse 10mm slices, corpus callosum to arch)
    • 3D TOF MRA if there is no perfusion
    If required you can add the following sequences according to the Lesion
    • Coronal T2 for periventricular/basal ganglia infarct
    • T1 Axial for the acute bleed-hemorrhage or hemorrhagic transformation in the region of infarct
     Optional Sequences in "Acute Stroke MRI Protocol"

    • Ax Permeability (30 sec delay)
    • Cor CEMRA: Carotids/Arch (22g insyte: 10cc Gadovist @ 1.5cc/sec. 30cc saline @ 1.5cc/sec, cover vertebral and carotid arteries posterior to anterior, aortic arch to top of COW)
    • Axial Perfusion (0 Delay)
    • Axial T1 Post-Contrast

    Role of Diffusion:
    Most sensitive and relatively specific.
    Based on principle of restriction of normal Brownian motion of water molecules in infarcted tissue.
    Infarct seen as an abnormal white area and described as an area of restricted diffusion.

    Role of FLAIR:
    Sensitivity to pick an infarct is arbitrarily comparable to CT.
    If an infarct seen on  diffusion and not seen FLAIR called FLAIR / Diffusion Mismatch indicate hyper acute infarct - reversible  ischemic changes and salvageable tissue or  tissue at risk.
    If changes are marked on FLAIR indicate already infracted and non salvageable tissue.

    Role of T2* GRE:
    Used to demonstrate hemorrhage or hemorrhagic transformation in the region of infarct as an alternative to CT.
    Area of bleed appear dark due to paramagenetic effect of blood degradation products.

    MR Angiography of brain and neck: 
    To demonstrate any major vessel stenosis or occlusion.
    No contrast required.Accuracy acceptable.   


    ADC




    READ MORE CLICK THE FOLLOWING LINKS:

    Pediatric Brain with Contrast MRI Protocol






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