Monday, June 27, 2011

Cochlear implants and the Radiologist


9 yr old girl  shows presence of cochlear implant in situ, shows  pneumocochlea, pneumocephalus, and subtle  fluid density in to the middle  ear location, possibly perilymph fistula,  through the  iatrogenic, intended cochleostomy. The electrodes appear close to cochlea particularly apical region and are normal. There is no evidence of infection on this. Treatment of such moderate air without parenchymal presence is usually conservative. Case and discussion by Dr MGK Murthy






Indication
Nonfunctional  (ganglion cells ineffective)cochlea on  both sides leading to bilateral sensorineural  deafness with intact auditory nerve function. Usually in children, but of late the adult varieties are receiving the implant

Contraindications
·         Obliterative labyrinthine ossification, severe cochlear or fenestrative otosclerosis, congenital cochlear  malformations(mondini deformity, ossified cohlea etc), severe bilateral temporal bone fractures, Infected middle ear
·         Usually HRCT temporal bone would evaluate all , but some prefer MRI to evaluate 8th nerve, speech and language functional MRI as well


Normal hearing
Sound from the environment—via the external and middle ear(including tympanic membrane and ossicles)--- Cochlea spiral ganglion cells----auditory nerve---brainstem.

Implant  has two parts

External-microphone  to pick the environment sound
-Speech processor-digitizes the signal
-Transmitter-converts to FM type  of Radiosignals

Internal –kept aligned well by the magnets , and placed underskin behind ear
  -Receiver/stimulator(disk shape)-converts FM signals to electric signals
- through a wire connected to Electrodes(usually 24)
-stimulate the spiral ganglion cells (apical better because sound will be more natural)------auditory nerve---brain. Sound produced is different from ordinary and robotic, needs adjustment, because 24 electrodes cannot match 15000 haircells normally present

Surgery
Making communication between mastoid/ middle ear and mastoid / cochlea . Intra -operative Radiographs help in correct positioning of the electrodes


Complications
Extra cochlear placement of the electrodes including in the semicircular canals, breakage facial palsy, infection, pneumocephalus, fluid drainage, meningitis, cochlear damage during insertion of electrodes, osteogenesis, vestibular symptoms etc

MR Safety
Previously thought to be Unsafe (because of the magnets with in the gadgets), recent models are classified as conditional (can be performed with specific recommendations of the manufacturer  including the magnetic strength)

HRCT (if needed with contrast) is adequate for post operative evaluation including electrodes malpositioning

Saturday, June 25, 2011

Umblical Artery Reference Calculator

Just came across this link on Perinatology.com  which has an excellent tool for calculation of reference range for umblical artery doppler parameters based on article -Am J Obstet Gynecol.2005;192:937-44

UMBLICAL ARTERY REFERENCE RANGE CALCULATOR

Glenoid Subchondral Cystic Lesion -Approach.




A 23 year old young male after a fall from motor bike complains of chronic pain of 2 months duration. MRI shows a well defined, regular, complex heterogenously altered lobulated completely intraosseous lesion in the subchondral location of the glenoid with no expansion / bleed / labral / cartilage / joint involvement. The differential diagnosis is possibly intraosseous ganglion, post traumatic cyst ( no bleed or fluid / fluid level or heterogenity would make this less likely ), osteoid osteoma ( absence of nidus make this unlikely). Caries sicca ( uncommon location, septal indentification predomiant fluid make this less likely). Case by Dr MGK Murthy and Mr Abdul Hamid.




Teaching points
Intraosseous ganglion cyst are uncommon entities in general with femur and medial malleolus accounting for majority of them, followed by knee and ankle regions. Bone scan / X-ray would suggest presence of activity and no significant calcification.
            

Wednesday, June 22, 2011

Radiology MCQs-Maharashtra Mch Exam


Q- Pseudo billroth sign is present in
Crohns
ca stomach
 ulcer

Answer
The earliest radiographic sign in Crohn's disease is aphthous ulcers. The most common radiologic findings in gastroduodenal Crohn's disease are mucosal nodularity, or “cobblestoning,” thickened folds, and ulcerations. A pseudo-Billroth I appearance of involved antrum and proximal duodenum has been described. A rare but classic radiographic finding is the funnel-shaped deformity of diseased antrum and duodenal bulb, known as the “ram's horn” sign

Q-scimitar sign is present in
 1 ca rectum 
2 chordoma 
3 sacrococcgeal teratoma
 4 anterior meningocele

Answer-
Anterior sacral meningocele is an unusual lesion that usually presents as a presacral mass. Radiography of the pelvis demonstrates a sacral deformity or “scimitar sign” that is pathognomonic for anterior sacral meningocele.




Fibrous Dysplasia of Maxilla

 Fibrous dysplasia of the facial skeleton commonly involves the maxilla.  It commonly involves one maxilla.  CT scan shows a lesion that is confined to the bone with no soft tissue component. It is helpful in distinguishing fibrous dysplasia from a malignancy. Features of malignancy include osteolysis, destruction of sclerotic margins, and cortical destruction with soft tissue extension.  The bony lesion shows a homogenous matrix with obliteration of maxillary sinus cavity.


Buford Complex-Normal Variant


 An absent anterior superior labrum and an associated cordl like middIe glenohumeral ligament represent the normal variation that is known as the Buford complex rather than an avulsed labrum. This normal variation may be mistaken for a detached labrum.





Tuesday, June 21, 2011

Calcaneal Fracture-Plain Film

56 yr old with history of fall from ladder. Case discussion series by Dr MGK Murthy.


1.What is it?
It is calcaneal fracture–comminuted, intra articular variety of tuberosity fragment fracture with Bohlers angle reduced




2.How many type are there?
Mainly two- Intra (important) and extra articular

3. Subtypes?
Primary fracture line is through the posterior  facet (uncommonly it can be anterior or middle)

Three-
a) sustentacular fragment(constant)
b) Tuberosity fragment------- leads to incongruity of post facet ---widening and shortening of heel------further damage-----tuberosity fragment creation(superolateral fragment of posterior facet)
c) if axial load bearing continues –Thalamic fragment(depressed posterior part of the posterior facet)


4. Complications ?
Calcaneal cuboidal joint displacement Tendoachilles/peroneal tendons distraction
Heel short and wide
lateral wall comminution/talus dorsiflexion

5.Associated injuries? (Mechanism -fall from height)
Other foot/spinal
Soft tissue compartmental syndromes
Fracture blisters

6.Radiography?
True lateral and oblique play more role along with other side comparison in case of doubt. Bohlers angle (normally 20 -40 deg)(intersection line drawn from the most cephalic portion of tuberosity to highest point of posterior facet)is critical.

7.Best way to calculate?
MDCT

8. Management
Initially all -with rest and elevation till swelling subsides
Then if bohlers angle mildly or moderately reduced – conservative, if severely reduced (< or equal to 0)- surgery

Monday, June 20, 2011

Telerad Providers Nominated in eWorld Forum-Support by Voting


We are proud to announce that our company has been nominated for the category "ICT Enabled Diagnostic Service Provider". The final decision will be based on Public voting and Jury's opinion. Your votes are precious. Please support at  and vote for Teleradiology Providers-Imaging Remotely.

ICT Enabled Diagnostic Service Provider




Sunday, June 19, 2011

Mobile Version of Sumer's Radiology Blog

Finally realized by going through my weblog stats that around 20% of my viewer-ship is on mobile phones and for them i have now optimized the template for viewing on mobile phones. It looks great on my iPhone.Thanks to blogger's excellent template tools.

Are you viewing this on your mobile phone? Do you like the change?

Friday, June 17, 2011

Recurrent Dislocation Shoulder- MRI

This patient has a history of previous dislocations, 17 year old  boy with evidence of altered contour and possible periosteal sleeve avulsion involving the anteroinferior labrum with asssociated localized fluid collection in relation to anterior labrum possible labral tear and associated paralabral cyst. Likely ALPSA lesion: anterior labroligamentous periosteal sleeve avulsion. In the Bankart lesion, the anterior cartilage labrum is detached and torn from the periosteum. In the ALPSA, the labral fragment remains attached to the periosteum of the scapular margin and can be tethered in this abnormal position, increasing the likelihood further medial displacement and of re-dislocation.




Striatocapsular haemorrhage-MRI

13 yr old with movement disorders with history of hypoxia. MR shows bilateral, symmetrical linear altered  signal intensity with no restricted diffusion or blooming on susceptibility images. Possibly represents striatal haemorrhage sequelae in the external capsular area between lateral putamen and insular cortex. By Dr MGK Murthy, Mr Hamid and Dr Mukarab.



Teaching points

Striatocapsular haemorrhage is classfied by chung etal
type1-Anterior                                  in the region of artery of heubner
type2-Middle-                                   in the  region of medial lenticulostriatal  artery
type3-Posteromedial-                       in the region of Postero medial branches of  lateral lenticulostriatal artery
type4-Posterolateral-                        in the region of postero lateralbranches of lateral lentiuclostriate artery
type5-lateral-                                   Most lateral branches of lateral lenticulostriatal artery
type6-Massive 

Stress Fracture Sacrum -Case Discussion


50 yr old post menopausal lady with back pain. Case submitted by Dr MGK Murthy.

(A)What is the finding?
An ill defined, irregular ,marrow oedema with no joint abnormality with subtle vertical dark line on T2



(B)What is the diagnosis ?
The finding is nonspecific to etiology. The possibilities include
-Bone marrow syndrome -this  is supported by  focal osteoporosis on Xray, however is unusual site for occurrence
 -Insufficiency fracture-possible because of the gender and age ,as well as subtle darkline on T2 and the orientation is vertical .
However there is no horizontal component across the middle of sacrum at S2 or S3 , and the second vertical component of Honda sign
- sacroilitis of non specific cause-  is unlikely as the joint is not abnormal
-sacroilitis of infective variety possibly TB-unlikely as there is no destruction, joint involvement, and no soft  tissue collection

(C) what should be next step?
Radionuclide scan will show Honda sign of  increased activity. CT would show fracture line

(D) what should be done if the patient is not keen get other tests done?
As the treatment is usually conservative ,  Review after treatment for at least 6 weeks is helpful

(E) Is it necessary to do Review MRI?
No , A review Xray  would be adequate , as it is likely to show sclerosis along the fracture line

Thursday, June 16, 2011

Acquired cystic kidney disease


End stage renal disease on dialysis for 10 years with ultrasonography showing multiple renal cysts. The MR urogram shows multiple cysts of varying sizes involving both kidneys with normal pelvicalyceal system with no splaying and normal kidney sizes. All the cysts fall into Bosnaik type-I or type-II and hence are possibly to be ignored. Acquired cystic kidney disease ( ACKD) is frequent finding in patients long term dialysis. Case by Dr MGK Murthy and Mr Hamid

Teaching points :-
1)      Criteria for ACKD
-        Presence of atleast 1 to 5 kidneys cyst
-        Pathologically an extension to the cyst more than 25% of the renal parenchyma.

 2)      Usually ESRD kidneys are small in size. However normal to enlarged kidneys in ESRD are known to occur in specific causes.

Wednesday, June 15, 2011

MR Arthrography Shoulder

Teaching points 
Usually done under fluoroscopy /ultrasonography/CT guidance to avoid labral cartilage injury. By Dr MGK Murthy and Dr Sudheer Kunkunuru

·        Indications
1.   Primarily for Rotator cuff tear suspicion or evaluation
2.   Cartilage evaluation
3.   All the internal structures including glenohumeral ligaments



·        Technique

PreArthrography  Xray shoulder AP with external and internal rotation views to look for presence of hydroxyl apatite crystals/calcification (which could be confused with rotator cuff  tear producing contrast leak)

-Supine and external rotation
-Mark the joint lateral to humeral head cortex
-20 to 22gauge LP needle perpendicular to fluoroscopy beam. Testing the safe INJOINT position with local anaesthetic after aspiration to test for blood vessels
-Confirm position with iodinated  contrast
- Dilute gadolinium injected to the comfort level usually
10 to 16 ml (Cocktail made of 0.1 ml Gadolinium+10ml Iohexol+10ml 0.9%saline+0.3ml of epinephrine of 1:1000 in 20 ml syringe )

Monday, June 13, 2011

Teleradiology Providers-Interview in Medindia


Lakshmi Gopal of Medindia spoke to Sumer Sethi, MD, Sr Consultant Radiologist and Director of Teleradiology Providers, a unit of Prime Telerad Providers Pvt Ltd. An author of many academic papers and books on radiology, Dr Sethi specializes in musculoskeletal and neuroradiology.  The demand for radiologists is great in India and abroad - they are, however, in short supply. 


Teleradiology helps adjust this imbalance. India has a lot of talent and our doctors have emerged as one of the major providers of teleradiology services in the Indian subcontinent, the US, Africa, and the Middle East. Its key strength is that we have extensive experience working across both public and private hospital facilities. We have sub-specialist abilities and experience in the areas of neuroradiology, breast and cardiac imaging.  We also provide our own customized teleradiology software along with a dedicated web-based server platform and have the ability to link up with any centre in the world irrespective of the Internet speeds available. 

 Interview is featured here- 

Friday, June 10, 2011

Anterior Cruciate ligament Reconstruction – what the Radiologist needs to know?

Young male with history of ACL reconstruction about 1 year back shows good positioning an ligamentization of the  the graft, normal PCL and menisci with subtle free fluid  with too anterior placement of tibial tunnel, post bioabsorbable screws. Case submitted by Dr MGK Murthy, Mr Hari Om, Mr Sahadev Gupta. 


Healthy Graft on MRI should be:
-Low signals if intact unimpinged graft
- Posterior to but not in contact with intercondylar roof
- T1 shows the structure better than T2 because of inherent heterogeneity on T2
-Tibial tunnel should not be too anterior
-Posterior cruciate ligament signals should not be gray/ heterogeneous






(A)        Technical factors evaluation

On X –ray
-fractures/screws integrity or position/union of bony portion/tunnel placement/size of screw tunnel

On MRI
 -Tunnel positioning (common failure is far too anterior placement at tibia )
-Tunnel widening(harmless)
-Graft integrity(heterogeneous signals sign of tear) other soft tissues evaluation
-Femoral insertion  should be at intersection of blumensaat line (intercondylar roof)and extended line from posterior femoral cortex
-Tibial  tunnel should  be posterior and parallel  to tibial intersection of blumensaat line

(B)        Biological factors
-failed ligamentization—not well seen on MRI
-infection
-Arthrofibosis—seen as low signal nodule surrounded by fluid , anterolateral to tibial tunnel called Cyclops lesion on MR (consists of debris of remnant ACL and graft )
-infrapatellar contracture syndrome 

Is it a segond's fracture?


Tibial plateau on lateral  aspect shows subtle ill definition and distal tibia below the plateau is unremarkable  with no definite avulsion fragment  away from the bone even on tunnel view (superior to AP view) and hence it is possibly normal gerdy tubercle and does not represent segond’s fracture, however, if clinically relevant  MRI would help exclude segond’s and associated injuries. Case submitted by –Dr MGK Murthy. 



 Teaching points 
Lateral tibial avulsion fracture is referred to as segonds fracture ( eponym being named after Dr Paul Segond).  Originally thought to be a result of avulsion of the medial third of the lateral collateral ligament, more recent research suggests that the insertion of the iliotibial tract (ITT) and the anterior oblique band (AOB), a ligamentous attachment of the fibular collateral ligament to the midportion of the lateral tibia, also play an important role. Associations   ACL tear(75 to 100%), any of the meniscus(66 to 70%), avulsion of the  fibular head  fracture, avulsion of gerdy tubercle. Avulsion fracture of medial collateral ligament associated with   PCL and medial meniscus injuries is referred to as reverse segond’s fracture

Wednesday, June 08, 2011

Ganglion Cyst of ACL-MRI


Young male with pain knee joint with lachmann test negative shows a well defined, regular, lobulated, complex fluid signal intensity, space occupying lesion replacing the body and femoral attachment of the ACL with presence of internal septae, with rest of the study unremarkable – Ganglion cyst of the cruciate ligament is likely. Case submitted by Dr MGK Murthy.






Crowdsourcing Radiology Reads


Outrageous it may sound but the thought has been around on the web for some time now. There are some people who are of opinion that Image interpretation  is one aspect of medicine that may sometime be read by collective intelligence.  Have seen patients in the past who have some uncommon disease and they have done their own research on the internet about their disease and its radiological findings, and in turn they are sometimes able to do a better job than overworked unaware radiologist.  Probably this may lead to some way of crowd sourcing-  may be in future we might have patients putting up their images minus the identification on this crowd sourcing portal and have everybody comment on the images, they may other patients with similar diseases, Doctors, radiologists in other countries and help them reach to final conclusions. Something like Wikipedia versus Peer review journals, i rely more on Peer reviewed material, but i find myself on wikipedia more often whenever i am  looking  for something and i usually get the information. I am not sure of the legal implications though and it may just become an aid to the patient’s quest for diagnosis. 

What are your thoughts on this? Do you think this would happen in near future?

Tuesday, June 07, 2011

Musculoskeletal Plain Film Series


15 yr old with history of trauma

1. How do we read the radiograph?
There is evidence of mild increase in the humero-acromial width on the right as compared to the left
Acromion on the right is ill-defined and stippled with loss of outer marginal definition. Glenohumeral and acromioclavicular articulations and rest of the study is  normal

2. Is this  a  fracture?
This case is complex in that it shows stippling and not bilaterally symmetrical  as well as there is sublte  width increase  an may be possibly periosteal response of the mid humeral shaft


3. why not os acromiale ?
Good question
Os acromiale is present in about 15% of population
Acromion arises by 2 -3 separate ossification centers between 14 to 16 years and coalesce by 19 years with each other and join the main bone by 20-25 years
The catch in this is- it is invariably bilateral and in our case only the right acromion is stippled and asymmetrical

4. How do we report ?
I would be concerned about the duration of trauma and if it is more than 6-7 days , findings of increased width, humeral shaft response and irregular acromion would go in favour of acute osteomyelitis

5. In this case what happened?
The history in this case is fall few days ago and and I am inclined to go in for the infection superimposed on haematoma

6. What should be radiology follow up?
Academically MRI would solve all the problems .it will show marrow edema, soft tissues, fluid in the joint, and show  true nature of acromion finding

7. Is there any other way?
 One needs to treat it as infection  after blood tests, Chest Xray (as the infections are possibly staphyloccus)  and review x ray after 3 weeks would give true picture



Monday, June 06, 2011

Diffusion Tractography-Made Simple

Teaching points
 Diffusion(Brownian Movement)denotes random motion of molecules at temperatures more than absolute zero. If it is equal in all directions called isotropic (as in grey matter). However in white matter diffusion is restricted to perpendicular to the long axis axonsand diffuses faster along the Z axis and is called ANISOTROPY. By acquiring multiple images each sensitive to diffusion to different orientation, fit the model (diffusion tensor)to measurements , can quantify mean diffusion and its orientation dependant of each voxel(Fractional anisotropy). Submitted by Dr MGK MURTHY.

Estimate mean diffusion, fractional anisotropy and maximum diffusion orientation to construct white matter paths. Mapping principal eigen vector, in each voxel ,forms basics of tractography. Sequence used is Single shot EPI. Disadvantage is no spatial /directional anisotropy. To get over this, we give color coding to tell directions.
Blue=superior/inferior
Green=Anterior/Posterior
Red=Left /Right

On 2D wherever fibers cross, mixture of colors are formed

Yellow=Green+Red
Magenta=Red+Blue
Cyan=Green+Blue

Other disadvantages include, inability to differentiate anterograde or retrograde connectivity, presence of synapses, and whether the path is functional.

There are 4 basic types of fibers

1. Projection fibers

–corticobulbar (cortex to brainstem)
-corticospinal(from pre/post central sulcus to spinal)
-Thalamic projections (post thalamic projections consist of optic radiation)
All these pass through the internal capsule



2.Association fibers
-superior longitudinal fasciculus (goes to most lateral of temporal region with C shape)
-Inferior longitudinal fasciculus
-inferior fronto-occipital fasciculus (ILF and IFOF go to post temporal/occipital regions)
-Uncinate fasciculus(IFOFand UF go to frontal lobe )
-superior fronto occipital fasciculus (only one to project medially along thalamus and ventricle)

3.Limbic system fibers
-cingulum(from cingulate gyrus to temporal lobes)
-Fornix(goes to hypothalamus)
-StriaTerminalis (goes to temporal lobe)
-Hippocampus
-Amygadala

4.Callosal fibers

-Genu(projections from this form forceps minor)
-Splenium(projections from this form forceps major)
-from splenium to temporal lobe along lateral ventricle forms Tapetum

Clinical uses

a) Temporal Lobe Epilepsy(TLE)
b) Multiple sclerosis (MS)
c) Amyotrophic lateral sclerosis (ALS)
d) Neuropsychiatry particularly schizophrenia
e) Cerebral palsy
f) Early acquired blindness







Radiology Workshop- Update

This is the intial flyer for 2012 MSK Radiology Course in Penang. If anyone is interested they can contact the organisers directly on msk.rad@gmail.com .

Friday, June 03, 2011

Unusual secondary ossification center for scaphoid tubercle-Plain Film

11 yr old child with history of trauma with pain wrist. Questions between Professor and the resident. Submitted by Dr MGK Murthy.
1.What is this?
Stippled scaphoidal tuberosity region with no associated soft tissue or articulation abnormality

2. is it fracture?
Even though there is history of fall , this not likely to represent fracture

3. Then what is the possibility?
In this age group(11 years) , unusual secondary ossification center for scaphoid tubercle needs consideration

4.When does scaphoid osification center normally appear?
It varies between 4 to 7 years

5. How to confirm?
Follow up after 2 weeks and comparison wwith other noninjured side is usually rewarding, as it is often bilateral

6. when do we confirm that it is secondary ossification center?
After the union of the bone in the normal course ,though sometimes it could remain separate

7. what is the importance of tubercle of scaphoid?
Flexor retinaculum and abductor pollcisbrevis are attached here

8. What are accessory bones of scaphoid?
Refers to replacement of residual secondary ossification centers. It could also occur on account of trauma or heterotopic ossification in synovial tags

9. can you name few?
-Os centrale is between scaphoid/capitate and trapezium
-Os Radiale externum located at the distal border of the scaphoid
-Os epitrapezium between scaphoid and trapezium
-Os epilunatum between scaphoid and lunate
-Os epiradial syloideum between radial styloid and waist of scaphoid
10. Will cross sectional imaging with MDCT or MRI would help in this child?
No. it is unlikely to help as we are not suspecting bone bruise or fracture







Thursday, June 02, 2011

Rare vertebro-vertbral fistula treatment


42yr / male presented with sudden onset weakness of right superior extremity.Weakness progressed rapidly to both superior extremities. K/C/O Neurofibromatosis. MRI and Digital subtraction angiography (DSA) demonstrated a very rare condition: Vertebro-vertebral fistula (VVF). The VVF was completely embolized (cured) by endovascular coiling with excellent recovery in power.

Case by

Dr. Sibasankar Dalai, MD, FACP
Fellow, Australasian College of Phlebology,
Member, American College of Phlebology.


Wednesday, June 01, 2011

Patellar Tendon Rupture-MRI


Young adult with history of  RTA shows complete tear of patellar tendon  midsubstance with involvement of retinacula ,  retraction of patella  with extensive haemorrhage and oedema of the soft tissues with involvement of hoffas  pad of fat. ACL  shows tear as associated finding. Case submitted by Mr Sahadev Gupta, Hariom, Dr Akshay & Dr  MGK Murthy



TEACHING POINTS
  • Rectus femoris fibres continue down the anterior aspect of patella  as patellar tendon.
  • Vastus lateralis continues as lateral and medialis continues as medial retinaculum and these are often involved in patellar tendon rupture.
  • MRI is the modality of choice though high frequency USG would show acute tear as hypoechoic region in experienced hands.
  •  Treatment is surgical repair as early as possible and preferably after 4-7 days to reduce the post surgical  infection due haematoma  before that 

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