Classification of Modic endplate changes in degenerative spine disease

Degenerative vertebral endplate and subchondral bone marrow changes were first noted on MR imaging by de Roos et al in 1987.A formal classification was subsequently provided by Modic et al in 1988, based on a study of 474 patients, most of whom had chronic low back pain (LBP). These authors described 2 types of endplate and marrow changes:


Type 1 changes were hypointense on T1-weighted imaging (T1WI) and hyperintense on T2-weighted imaging (T2WI) and were shown to represent bone marrow edema and inflammation.

Type 2 changes were hyperintense on T1WI and isointense or slightly hyperintense on T2WI and were associated with conversion of normal red hemopoietic bone marrow into yellow fatty marrow as a result of marrow ischemia.

Type 3 changes were subsequently described as hypointense on both T1WI and T2WI and were thought to represent subchondral bone sclerosis.

Mixed-type 1/2 and 2/3 Modic changes have also been reported, suggesting that these changes can convert from one type to another and that they all present different stages of the same pathologic process.

Modic Change
Type 1 :T1 Low T2 High
Type 2 : T1 High T2 High
Type 3 : T1 Low T2 Low

Salt and Pepper Sign

This sign is seen on MRI images in paragangliomas such as glomus tumors .

The sign is indicative of the hypervascularity of the mass. The 'pepper' represents multiple areas of signal void of vessels and the 'salt' represents the hyperintense foci due to slow-flow vessels or hemorrhages in these hypervascular tumors. The sign is seen in tumors that are more than 1 cm in diameter. The sign is not specific for paragangliomas and has been reported in other hypervascular lesions such as metastatic hypernephroma and metastatic thyroid carcinoma. Four common locations of paragangliomas in the head and neck are the carotid body, the jugular foramen, along the path of the vagus nerve, and the middle ear. Paragangliomas can be multiple and bilateral, especially in familial cases, and hence evaluation of the entire neck and of both sides is needed.

This term is used also for:

Sjogren syndrome
The parotid gland in Sjogren's syndrome has also been described as having a salt and pepper appearance, due to a combination of punctate regions of calcification (pepper) and fatty replacement (salt)

Vertebral haemangiomas
A less common usage for the term is for vertebral haemangiomas which have a courser black and white dotted appearance especially on axial T2 and T1 images (salt = fat, pepper = coarsened trabeculae).

MRI noise artefact
A related use of the term is to describe the noise sometimes seen in MRI images.

When you think about it, you can probably find folk who have used the term for all sorts of lesions... any lesion that has a fine granular imaging texture will do the trick.

Erdheim-Chester Disease

T1 mdc, T2, T1 Meningioma????? strange signal on T2 image!!!
It isn't a Meningioma, it's Erdheim-Chester Disease.
Rare condition thought to be a histiocytosis of the non-Langerhans cell type, with widespread manifestations. It is a systemic lipogranulomatous disorder with infiltration by foamy, lipid-laden histiocytes and giant cells, with or without fibrosis. Musculoskeletal involvement is relatively characteristic.
Dural accumulations, may mimic meningiomas, although the signal characteristics are somewhat different, as the accumulations in ECD are low on T2.

In the intracranial district it can involve also hypothalamus, pituitary infundibulum: presenting with diabetes insipidus, and retro-orbital tissue.

neuradiological sign: Dural Tail

Dural tail sign
This sign represents thickening and enhancement of the dura mater in continuity with a mass, which on MR images, gives the appearance of a tail arising from the mass. The dural tail is thought to represent reactive change; however, it may also be due to tumor invasion.Three criteria need to be met for a 'positive' dural tail sign: the tail should be seen on two successive images through the tumor, it should taper away from the tumor, and it must enhance more than the tumor. This sign has been traditionally considered as highly specific for meningioma. However, it is seen only in 60% of meningiomas and has also been reported in nonmeningiomatous lesions such as chloromas, primary CNS lymphomas, sarcoidosis, schwannomas, metastases, and syphilitic gummata.

Little Red Cap in the wood of neuroradiological signs

While walking in the woods, to bring a piece of cake and a
bottle of wine to her beloved grandmother, Little Red Cap
is abruptly confronted with a blizzard of unknown to her
neuroradiological signs.
Would you be willing to help the sweet little girl by
recognizing these signs and by coupling the neuroimages with
the corresponding inspiring objects, plants, animals, monsters,
and cartoons (Fig. 1)?

For a help looks for them into the next posts

clinical case: Pneumocephalus

A healthy 54-year-old woman presented with progressive abnormal acoustic sensations, aphasia, and visual-field disturbances. She reported no head trauma or recent infection, such as otitis media. An initial cranial radiograph revealed air in the left temporal region without evidence of a fracture (Panel A, arrow). A computed tomographic scan of the head showed a large amount of air in the left temporal lobe; the involved area was approximately 4 cm by 3 cm by 5 cm (Panel B, arrow).

Pneumocephalus is the presence of air or gas within the cranial cavity. It is usually associated with disruption of the skull: after head and facial trauma, tumors of the skull base, after neurosurgery or otorhinolaryngology, and rarely, spontaneously. Pneumocephalus can occur in scuba diving, but is very rare in this context.
If there is a valve mechanism which allows air to enter the skull but prevents it from escaping, a tension pneumocephalus can occur (similar to what can happen in a tension pneumothorax.
CT scans of patients with a tension pneumocephalus typically show air that compresses the frontal lobes of the brain, which results in a tented appearance of the brain in the skull known as the Mount Fuji sign.The name is derived from the resemblance of the brain to Mount Fuji in Japan, a volcano known for its symmetrical cone. In typical cases, there is a symmetrical depression near the midline (such as the crater of a volcano), due to intact bridging veins.
Its occurrence seems to be limited to tension pneumocephalus (not occurring in pneumocephalus without tension. The sign was first described by a team of Japanese neurosurgeons.

http://content.nejm.org/cgi/content/full/358/12/e13/F1

Clinical case

History : 30 years old man with new seizure

T2 and FLAIR images demostrate left frontal lobe cortical signal abnormality with subcortical cystic areas, this lesion has hypointense T1 signal and doesn't shows post contrast enanchement.

Diagnosis: Dysembryoplastic neuroepithelial tumour (DNET)

Dysembryoplastic neuroepithelial tumour (or DNET) is a benign (WHO Grade I) slow growing tumour arisig from either cortical (vast majority) or deep grey matter. They are thought to arise from secondary germinal layers and are frequently (upto 80% of cases) associated with co-existent cortical dysplasia, and is characteristically the cause of intractable partial seizures (see temporal lobe epilepsy).
They demonstrates essentially no growth over time, although very gradual increase in size has been described. As expected prognosis is excellent and even though these lesions are often incompletely resected, tumour progression is uncommon. Additionally even in cases of incomplete ressection, seizure frequently cease.
Location
The temporal lobe is the most common location, but all parts of the CNS containing grey matter are potential locations.
-temporal lobe: over 60% of cases
-frontal lobe: 30% of cases
-caudate nucleus
-cerebellum: presentation is then more commonly with ataxia rather than seizures
-pons

Radiographic Features
CT
if cortical may scallop the inner table of of the skull vault (44 - 60%)
calcification in 20 - 40% (more common histologically)
low density
no enhancement
MRI
high T2WI signal with high signal 'bubbly appearance'
FLAIR mixed signal intensity with bright rim sign.
low on T1WI
haemosiderin staining uncommon on Gradient Echo as bleeding into DNETs only occasionally occurs, although as calcification is not infrequent
no enhancement
no restriction on DWI
non-specific MRS although lactate may be present

Differential diagnosis
The differential diagnosis will depend on the location of the tumour.
Mesial temporal lobe
see also temporal lobe tumours
tumours (in order of decreasing frequency)
ganglioglioma
DNET
pilocytic astrocytoma
diffuse astrocytoma
oligodendroglioma
pleomorphic xanthoastrocytoma
cysts
neuroepithelial cyst
choriod fissure cyst
other
herpes simplex encephalitis: usually some bilateral changes, and different presentation
limbic encephalitis: usually some bilateral changes, and different presentation
mesial temporal sclerosis
Cortical
low grade astrocytoma
ganglioglioma
pleomorphic xanthoastrocytoma
oligoastrocytoma/oligodendroglioma
taylor dysplasia

Diffusion Weighted Imaging

Diffusion imaging makes use of the variability of “Brownian motion” of water molecules in brain tissue. Brownian motion refers to the random movement of molecules. Water molecules are in constant motion, and the rate of movement or diffusion depends on the kinetic energy of the molecules and is temperature dependent. In biological tissues, diffusion is not truly random because tissue has structure. Cell membranes, vascular structures, and axon cylinders, for example, limit or restrict the amount of diffusion. Also, chemical interactions of water and macromolecules affect diffusion properties. Therefore, in the brain, water diffusion is referred to as “apparent diffusion.”
To obtain diffusion-weighted images, a pair of strong gradient pulses are added to the pulse sequence. The first pulse dephases the spins, and the second pulse rephases the spins if no net movement occurs. If net movement of spins occurs between the gradient pulses, signal attenuation occurs. The degree of attenuation depends on the magnitude of molecular translation and diffusion weighting. The amount of diffusion weighting is determined by the strength of the diffusion gradients, the duration of the gradients, and the time between the gradient pulses.
Diffusion imaging is performed optimally on a high-field (1.5 T) echo-planar system, but it can be accomplished with a turboSTEAM sequence on systems with conventional gradients.
The diffusion data can be presented as signal intensity or as an image map of the apparent diffusion coefficient (ADC). Calculation of the ADC requires 2 or more acquisitions with different diffusion weightings. A low ADC corresponds to high signal intensity (restricted diffusion), and a high ADC to low signal intensity on diffusion-weighted images.
In the setting of acute cerebral ischemia, if the cerebral blood flow is lowered to 10 ml/100gm/min, the cell membrane ion pump fails and excess sodium enters the cell, which is followed by a net movement of water from the extracellular to intracellular compartment and cytotoxic edema. Diffusion of the intracellular water molecules is restricted by the cell membranes. The restricted diffusion results in a decreased ADC and increased signal intensity on diffusion-weighted images. Severe ischemia can lower the ADC by as much as 56% of normal tissue at 6 hours.
In patients who present with symptoms of cerebral ischemia, diffusion-weighted images are very helpful to identify any area of acute ischemia and to separate the acute infarction from old strokes and other chronic changes in the brain. Only the acute infarcts appear hyperintense on the diffusion
images. Subacute and chronic infarcts, vasogenic edema, the punctate and confluent changes of deep white matter ischemia, and dilated VR spaces are not bright.
Bacterial abscesses may exhibit restricted diffusion due to thick cellular debri within the central cavity. Other diseases of the brain, such as non-bacterial infections, neoplasia, contusions, and demyelinating diseases, are not associated with cytotoxic edema, and therefore as a rule, they are not hyperintense on the diffusion images. One exception is epidermoid tumors, which have restricted diffusion due to the waxy consistency of their contents. Also, the central portions of some primary and secondary brain tumors may exhibit restriction diffusion as they outgrow their blood supply and become ischemic. Occasionally, an acute MS plaque may be mildly hyperintense with diffusion weighting.
Lesions with prolonged T2 relaxation times are commonly mildly hyperintense on diffusion-weighted images. This phenomenon of “T2 shine-through” can easily be distinguished from true restricted diffusion on the ADC map. Only true restricted diffusion is low signal on the ADC map.





OTHER CAUSES OF POSITIVE DWI:

-Bacterial abscess

-Epidermoid tumor

-Acute demyelination

-Tumors undergoing central necrosis

-Acute encephalitis

-Jacob Crutzfeld disease

-Elevate protein or acute blood

-T2 shine-through

Differential Diagnosis: Posterior Fossa Mass

CHILD
Cerebellum/IVth Ventricle
- Medulloblastoma - midline, vermian or roof - usually hyperdense on plain CT - often enhance homogeneously
- usually PILOCYTIC ASTROCYTOMA - 2/3 are cystic with mural nodule - cyst fluid denser than CSF due to protein
- Ependymoma - INTRA-ventricular - "cast" of lumen - 50% are calcified
Brainstem
- Brainstem glioma - expands brainstem (infiltration w/o destruction) - hydrocephalus (may be late)
Extraaxial fluid collection
- Large cisterna magna ("Mega Cisterna Magna")
- Epidermoid inclusion cyst
- Arachnoid cyst (may bevel inner table of skull)
- Dandy Walker cyst of 4th ventricle
- Vermian agenesis
- Chronic subdural hematoma

ADULT
Extraaxial:
- Vestibular Schwannoma (CPA)
- Meningioma
- Ependymoma

Intraaxial:
- Metastasis - most common intraaxial neoplastic post fossa mass in adult
-Hemangioblastoma - cystic or solid - angio shows hypervascularity & stain
-Astrocytoma - usually not vascular on angio
-Medulloblastoma - often more lateral in adults

Rathkle's cleft cysts

Rathke’s cleft cysts (RCC) may occasionally present with symptoms of pituitary apoplexy, curiously in one small series only 2/6 had hemorrhage in the lesion at surgery so cause symptoms is uncertain.
Intralesional nodules help make the diagnosis of RCC and are believe to be due to mucinous material on histologic examination and cholesterol and protein on biochemical analysis. It has been suggested that the nodule is a concretion of material within the cyst and that the amount of protein in intracystic nodules influences MR signal intensity.

Demographics and clinical presentation
Rathke’s cleft cysts are typically asymptomatic and are found in 13-22% of autopsies. If large, they may cause visual disturbance due to compression of the optic chiasm or pituitary dysfunction due to compression of adjacent pituitary tissue and distortion of the pituitary stalk.
There appears to be a female preponderance with a female to male ratio of approximately 2:1.

Pathology
Rathke’s pouch forms during the 4th week of embryologic development as a rostral outpouching from the roof of the primitive oral cavity. The anterior wall of the pouch gives rise to the anterior lobe of the pituitary (pars distalis). The posterior wall of the pouch does not proliferate and remains as the intermediate lobe of the pituitary (pars intermedia). The lumen of the pouch narrows to form a cleft (Rathke’s cleft) that normally regresses. Persistence of this cleft with expansion is believed to be the origin of a Rathke’s cleft cyst.
The wall of the cyst is typically lined by a single cell layer of epithelium, often containing goblet cells, and often ciliated.
Radiographic findings
On imaging a Rathke’s cleft cyst is seen as a well-defined non-enhancing midline cyst within the sellar arising between the anterior and intermediate lobes of the pituitary. 40% are purely intrasellar and 60% have suprasellar extension, and purely suprasellar location, although reported, is rare.
On CT it is typically non-calcified and of homogenous low density. Uncommonly it may be of mixed iso- and low density, or contain small curvilinear calcifications in the wall (seen in 10-15% of cases)
On MRI the signal characteristics vary according to the cyst content which may be mucoid or serous. On T1, 50% are hyperintense and 50% are hypointense. On T2, 70% are hyperintense and 30% are iso or hypointense. In 70-80% of cases a small non-enhancing intracystic nodule can be identified which is virtually pathognomic of a Rathke’s cleft cyst. When seen it is hyperintense to surrounding fluid on T1 and hypointense on T2. Depending on the signal of the surrounding fluid it may be inapparent on one or other sequence.
No contrast enhancement of the cys is seen, however a thin enhancing rim of surrounding compressed pituitary tissue may be apparent.

Differential diagnosis
The main differential differential diagnoses are:
craniopharyngioma
no gender difference
similar age group
usually suprasellar or have a suprasellar component
cystic pituitary adenoma
arachnoid cyst
older patients
no gender difference
epidermoid cyst
usually suprasellar
restriction on DWI