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Internal auditory meatus xray

2011-12-27T07:09:00.000-08:00

1. Straight anterior posterior view, with beam passing through the orbits, no angulation. Tomography may be done coronally for better visualization.

2. Modified Stenver's view

For assessment of cochlear implant patient - able to visualize the electrode array and petromastoid anatomy.

Patient lie supine with head rotated towards the normal side, tube angled 15 degree caudally.

CR is parallel to modiolar axis (central axis in the cochlea).

* arrow: internal auditory meatus!

Source: Cochlear implants: a practical guide by Huw Cooper

CSF

2011-12-22T17:26:00.000-08:00

Cerebrospinal fluid is produced by the epithelial cells of the choroid plexus which are found in:

Inferior (temporal) horn and atrium (body) of lateral ventricle
Third ventricle
Fourth ventricle

CSF flow

It is produced at 0.4ml/min, approximately 600ml in 24 hours ( independent of CSF pressure).

Apart from ventricles of the brain, CSF circulates more in the subarachnoid space in the cisterns and spinal canal. 25ml of CSF is within and around spinal canal. This process is by passive diffusion.

From the inferior horn CSF flows to body of lateral ventricles passing through interventricular foramen of Monroe to the third ventricle.

Then it goes to the fourth ventricle through aqueduct of Sylvius.

Lower part of the roof of fourth ventricle has three openings: the larger median aperture of Magendie and two lateral aperture of Luschka. CSF flows to cisterna magna through median aperture and to pontine cistern through lateral aperture.

Pontine cistern communicates with interpeduncular cistern superiorly.

The interpeduncular cistern further communicates with suprasellar cistern superiorly and ambient cistern laterally.

Suprasellar cistern extends laterally into Sylvian cistern. Optic nerve pass to the chiasm in anterior part of suprasellar cistern a.k.a chiasma cistern.

The chiasma cistern and suprasellar cistern continuous superiorly as cistern of lamina terminalis and pericallosal cistern.

This continuous posteriorly as quadrigeminal cistern.

The ambient cisterns are also continuous with quadrigeminal cistern posteriorly.

Pulsations of arteries within the cisterns play a role in CSF directional flow.

From the basal cisterns, some fluid flow down and bathes the spinal cord.

The remainder passes upward to the tentorium hiatus and diffuses over the surface of cerebral hemispheres.

CSF is absorbed through the arachnoid villi (herniation of arachnoid through holes in dura) which are numerous in superior sagital sinus.

* Pacchonian granulations (arachnoid granulations) in children that aggregates into a visible clump.

The ventricles

Lateral ventricle

- consists of four parts:

inferior horn (temporal horn) - extends anteriorly to the temporal lobe, may not be seen in imaging unless dilated. Its lateral wall is formed by tapetum, floor is formed by the hippocampus.
body (atrium) - within the parietal lobe, its medial wall formed by septum pellucidum, roof and lateral wall are formed by corpus callosum and tapetum, floor by thalamus medially and caudate nucleus laterally.
anterior horn (frontal horn) - extends into frontal lobe
posterior horn (occipital horn)- extends into occipital lobe. Often asymmetrical or present one sided usually on left side. Only 12% subjects are bilaterally well developed.

Third ventricle

- slit like, increasing size with age. Normally 2-10mm diameter.

- two recesses: supraoptic recess anteriorly (<3cm in size), suprapineal recess posteriorly.

- lamina terminalis: thin anterior wall of third ventricle between anterior commisure above to the optic chiasm below it.

Fourth ventricle

-Floor is diamond shape (rhomboid fossa), formed by posterior surface of pons and upper prt of medulla.

-Roof formed by superior cerebellar peduuncle @brachium conjunctivum with superior medullary velum in between, and inferior cerebellar peduncles @ brachium pontis with inferior medullary velum between.

-Should be symmetrical, otherwise suspect pathology

-Choroid plexus invaginates lower part of its roof.

* Fifth ventricle

-@ cavum vergae

-posterior part of foramen of Monro

-begin to close from posterior to anterior in 6 month POG, complete obliteration by 2 months of age in 85% infants.

- does not exist without cavum septum pellucidum

Aqueduct of Sylvius

-measures 15mm in length, 2mm in diameter

-passes between tegmentum (part in midbrain) and tectum (quadrigeminal plate)

-surrounded by CN III, IV and V --periaqueductal grey matter

Mam-mo-graphy :)

2011-12-22T16:50:00.000-08:00

Routine view of mammography are:

Cranio-caudal: to view inner (medial) and outer (lateral) breast, the nearest to labelling is the outer part.
Medio-lateral oblique: to view upper and lower part of the breast.

11 criteria of good mammographic cranio-caudal view:

Medial and lateral breast tissues are included as mush as possible
Nipple in profile
Aim to include pectoralis muscle
Symmetrical breast tissue
No shoulder or skin fold in the view
Good compression- able to see skin pores
Good exposures
No motion
No artefacts
Markers and ID are correct
Good processing

11 Criteria of good mammographic MLO:

Pectoralis muscle is visualized in full length
Pectoralis muscle viewed to nipple line
Nipple in profile
Symmetrical view
Inframammary fold viewed
No skin fold seen
Good exposures
No motion
No artefacts
Correct ID and markers
Good processing

Images may be assessed by CAD (computer assisted diagnosis) which could locate area of possible mass / calcifications.

Microcalcification are calcifications less than 0.5mm, reported as clustered or scattered calcifications.

Complimentary ultrasound should be done to:

First timer patient
Suspected mass / microcalcifications on MMG - to confirm area and nature
Post mastetectomy, to look for lesions at the scar region.

Source: Wikiradiography - Mammogram

Facial nerve!

2011-12-21T18:19:00.000-08:00

The motor nucleus of facial nerve is from the anterior surface of brainstem at pons, lateral to olive of medulla.
Together with CN VIII at cerebellopontine angle, they enter the internal auditory canal and this part is called INTRACANALICULAR PART (13-15mm).

In IAC, the facial nerve occupies superior compartment of crista falciformis together with superior vestibular nerve (branches of CNVIII).

It then goes sharply anterior (almost at right angle to the long axis of petrous bone) to reach the geniculate ganglion, making u-turn at the cochlea giving the genu of facial nerve. This part is called LABYRINTHINE PART (3-4mm).

It then runs posteriorly as TYMPANIC PART (8-11mm). Facial nerve is seen median and parallel to wall of epitympanum. From geniculate ganglion, it goes to the pyramidal eminence.

It runs superior to the oval window and inferior to lateral semicircular canal.

From pyramidal eminence, it makes another turn inferiorly and dive into the mastoid bone. Here it is known as MASTOID PART (10-14mm).

It exits through stylomastoid foramen, giving branch in FACIAL CANAL.

The branches are Greater petrosal nerve, Stapedius Nerve, Chorda Tympani nerve.

Terminal branches of facial nerves are: Cervical nerve, Mandibular nerve, Buccal nerve, Zygomatic nerve and Temporal nerve.

Source:

Erik Bee and Robin Smithius, Temporal bone anatomy, Radiologyassistant.

my new perfume

2011-10-29T19:07:00.000-07:00

Really loving it :)

Poppy flower mixes of bright fruits with soft florals.

Riedel's? riddles?

2011-10-29T18:40:00.000-07:00

Riedel's lobe is a broad tongue-like downward projection of the right lobe of liver, adjacent to the gallbladder.

It's a rare variant of liver, found in 5-10% of females. Rarely seen in males.

It is not a true lobe, and it may be mistaken as a mass.

Source: www.ultrasound-images.com

Preauricular sulcus

2011-10-29T18:26:00.000-07:00

Nooo..It's not a strcuture in the ear.

It's in the pelvis, characteristically seen in 25% of female.

This sulcus is anterior to sacroiliac joint, and superior gluteal artery runs thorugh it.

It is also known as Paraglenoid sulcus!

Dandy Walker

2010-04-20T20:38:00.000-07:00

It is characterized by (1) agenesis or hypoplasia of the cerebellar vermis, (2) cystic dilatation of the fourth ventricle, and (3) enlargement of the posterior fossa. It may be associated with atresia of the foramen of Magendie and, possibly, the foramen of Luschka.

Dandy-Walker malformations are formed during embryogenesis. Insults of varying severity to both the developing cerebellar hemispheres and the fourth ventricle are currently believed to be the genesis of this anomaly.

Multiple theories have been offered to explain the diffuse manifestations of Dandy-Walker malformation, but no single theory has proven satisfactory or has been widely accepted.
The etiology of Dandy-Walker malformation is heterogeneous, and familial occurrence has been reported as well. A few cases resulting from autosomal recessive genes have been reported, although in most patients, the cause of Dandy-Walker malformation is not known.
Genetic counseling is critical to estimate the risk of recurrence of genetic disorders in family members.
Dandy-Walker malformation occurs more frequently in females than in males.

Dandy-Walker malformation
Complete or partial cerebellar vermian hypoplasia
Cystic dilatation of fourth ventricle
Large posterior fossa
High torcular and transverse sinuses
Hydrocephalus

Image 1 shows agenesis of the corpus callosum, a hypoplastic brainstem (b), elevation of the torcular herophili (lambdoid-torcular inversion, large arrow), a large fourth ventricle, and a markedly hypoplastic vermis that is rotated superiorly (small arrow).

Image 2 showing ventriculomegaly and a superiorly displaced posterior fossa cyst.

Dandy-Walker variant
Varying cerebellar primarily inferior vermian hypoplasia
Varying enlargement of the fourth ventricle
Normal posterior fossa volume

Mega cisterna magna
Normal cerebellar hemispheres and vermis
Large retrocerebellar CSF collection communicates with fourth ventricle
Normal fourth ventricle
Occasionally, quite enlarged posterior fossa

Posterior fossa arachnoid cyst
Noncommunicating posterior fossa cyst
Normal but distorted vermis and cerebellum
Normal but displaced fourth ventricle
Usually enlarged posterior fossa
mainly showing features of mass effect

Reference:

http://emedicine.medscape.com/article/408059-overview

favourite items for january 2010

2010-01-13T05:33:00.000-08:00

Weee! i juz bought this perfume today and i'm so glad to hav it :)
Bought it from Metrojaya MidValley for RM237 - 50ml EDT+body lotion+lip gloss and miniature, nicely packaged in a cute makeup bag (big grin~)
This scent includes a mixture of water lily, apple, mandarin meringue, and golden apricot skin, dark chocolate, amber, musk, and vanilla.
It smells sooo good! Must have perfume,okay!;P

sCoTty DoG!

2010-01-09T20:43:00.000-08:00

It's actually a sign that we see on x-ray that represents Spondylolisthesis

The nose: transverse process
The eye: pedicle
The neck: pars interarticularis
The ear: superior articular facet
The front leg: inferior articular facet

A break in the neck of the dog, or a dog collar, corresponds to a fracture in the region of the pars interarticularis, which is specific for spondylolysis

X-ray 1: Normal oblique view lumbosacral x-ray

Spondylolisthesis is graded in this manner:
Grade 1-vertebral body above subtends ¼ of the AP diameter of the vertebral body below

Grade 2- vertebral body above subtends 1/2 of the AP diameter of the vertebral body below

Grade 3- vertebral body above subtends 3/4 of the AP diameter of the vertebral body below

Grade 4- vertebral body above subtends the full AP diameter of the vertebral body below

Xray 2:
Lateral view of the lumbar spine demonstrates a bilateral break in the pars interarticularis or spondylolysis (lucency shown by black arrow) that allows the L5 vertebral body (red arrow) to slip forward on the S1 vertebral body (blue arrow).

The normal pars interarticularis is shown by the white arrow.
The forward slippage is called spondylolisthesis.

The degree of forward slippage is equal to about 1/4 to 1/2 of the AP diameter of S1 so this is a Grade1-Grade 2 spondylolisthesis.

References:
1. Zubin Irani, MD, MBBS and Jehangir J Patel, MD @ http://www.learningradiology.com/archives06/COW%20204-Spondolytic%20Spondylolisthesis/spondylocorrect.htm
2. A. Gentili, MD @ http://www.gentili.net/signs/20.HTM

sPinAL ultrasound

2010-01-07T06:47:00.001-08:00

Today after 15 months in radiology department, i finally have a case for spinal ultrasound :)
Mainly all these conditions suspected to have spinal dysphrapism (SD) requires spinal US;
(i) a neurological deficit
(ii) cutaneous stigmata, such as a haemangioma, sacral pit or tuft of hair
(iii) other abnormalities associated with SD such as cloacal exstrophy or anorectal or sacral abnormalities and agenesis.
My patient presented with sacral pitting, with no nneurological deficits or symdromic features.

Spinal US are not only a diagnostic sensitivity equal to MRI. Furthermore it can be performed portably, without the need for sedation or general anaesthesia. MRI is highly dependent on factors affecting resolution, including patient movement, physiological motion from cerebral spinal fluid (CSF) pulsation and vascular flow, factors that do not affect Spinal US.

The quality of ultrasound assessment decreases after the first 3–4 months of life as posterior spinous elements ossify, and in most children Spinal US is not possible beyond 6 months of age. However, the persisting acoustic window in children with posterior spinal defects of SD enables ultrasound to be performed at any age!

HOW TO DO IT and WHAT TO LOOK FOR?
Actually it will be easier if you know the anatomy :)
Dont forget that L2 is at the same level of iliac crest!
The normal neonatal spinal cord is displayed on ultrasound as a tubular hypoechoic structure with hyperechoic walls. The central canal is hyperechoic, the so-called central echo complex. The subarachnoid space surrounding the cord is hypoechoic. The caudal end of the spinal cord corresponds with the conus medullaris, which continues into the filum terminale. The cauda equina is seen as echogenic linear structures surrounding a hyperechoic filum terminale. The vertebral bodies are seen as echogenic structures ventral to the spinal cord.

Particular features to note are:
(i)The level of the conus medullaris. In term infants the tip of the conus medullaris normally lies above the mid level of the L2 vertebral body although there is a large range of normality (from T10/11 to L2/3). In pre-term infants the tip of the conus lies between L2 and L4, i.e. the level of the conus moves proximally with age.
(ii) The position of the cord in a dorsal/ventral or anterior/posterior orientation. In normal infants the cord lies a third to half way between the anterior and posterior walls of the spinal canal.
(iii) Tethering cord may be represented with a low-lying cord, if the cord lies more posteriorly,
absence of pulsation of the cord and nerve roots and/or thickened filum terminale (normal <2mm).

Common types of spinal dysraphism
(i) SD occulta (without back mass)
- low cord
- tethered cord
-diastematomyelia
- spinal lipoma
- anterior sacral meningocoele
(ii) SD with skin covered back mass
- lipomyelomeningocoele
- myelocystocoele
(iii) SD without skin covered back mass
-myelocoele
-myelomeningocoele

Reference:
Spinal ultrasound in infants E A Dick et al, British Journal of Radiology 75 (2002),384-392 © 2002

hello people!

2009-11-19T01:31:00.000-08:00

yeay..finally i have my own blog!
it's really simple..
glad i've made it!
coz everyone blogs, right? (err..almost everyone ;))
please leave some comment to my upcoming posts ya!