Common compressive neuropathy Increase in the volume of the carpal tunnel or Reduction in the available space in the carpal tunnel leads to compression / mass effect over the median nerve MERCURY IMAGING INSTITUTE SCO 172-173 SEC 9C CHANDIGARH MERCURY IMAGING CENTRE SCO 16-17 SEC 20D CHANDIGARH CARPAL TUNNEL SYNDROME ULTRASOUND AND MR FINDINGS
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Common compressive neuropathy Increase in the volume
of the carpal tunnel or Reduction in the available space in the carpal tunnel
leads to compression / mass effect over the
median nerve
MERCURY IMAGING INSTITUTE SCO 172-173 SEC 9C CHANDIGARHMERCURY IMAGING CENTRE SCO 16-17 SEC 20D CHANDIGARH
CARPAL TUNNEL SYNDROMEULTRASOUND AND MR FINDINGS
CARPAL TUNNEL Dedicated assesment of the CARPAL TUNNEL carried out at three levels
• Distal radioulnar joint• Pisiform bone• Hook of hammate.
Fibro-osseous concave space in the volar aspect of the carpal bones and flexor retinaculum.flexor retinaculum is seen to extend from the scaphoid to tubercle of trapezium on one side and pisiform to hook of hamate on other side. Normal homogenous fat is appreciated in the carpal tunnel aling the dorsal aspect.
MEDIAN NERVE
NORMAL CARPAL TUNNEL
Flexor tendons are hypointense .
Flexor retinaculum has hypointense signal with minimal volar bowing .
Fat is appreciated normally in dorsal aspect of the tunnel.
Median nerve has normal fasciculated, nonfaceted , non angulated appearance.
MEDIAN NERVE
MEDIAN NERVE :It is normally placed in the volar and radial
aspect of the tunnel.NORMAL APPEARANCE
1. Oval with higher signal than adjacent flexor tendons .
2. Non faceted , non angulated , Fascicular appearance is normal.
3. Size decreases from Proximal to distal course in the carpal tunnel.
Some facts ...........................
CARPAL TUNNEL SYNDROME COMMON COMPRESSIVE NEUROPATHY
• SYMPTOMS =Pain in thumb/ index finger and radial aspect of the Middle finger.
• Worse at night .• Most common cause of the
syndrome is tenosynovitis of the flexor tendons. ( overuse as in typists).
Cardinal fetaures on MR imaging
• Focal / segmental thickening of the median nerve ( pseudoneuroma ) – compare size at distal radioulnar joint and at level of pissiform.
• Flatenning or angulation of the surface of the nerve in vicnity of the flexor tendons.
• Increased bowing ratio .• Increased signal intensity of the
median nerve. ( obstructed venous return with resultant nerve edema ).
Post op assesment .................
In case of failure
1. Incomplete release of the flexor retinaculum appreciated as intact part of the flexor retinaculum .
2. Low signal intensity fibrotic tissue in vicnity of the median nerve
3. Persistant / recurrent mass 4. Median nerve neuroma
1. Retinaculum is not completely seen.
2. Free ends of the retinaculum are appreciated with volar deviation.
3. Contents of the carpal tunnel show volar deviation.
Normal post op apperance after the release of the flexor retinaculum
VOLAR BOWING – Quantitative assesment for
carpal tunnel syndrome
VOLAR BOWING : Normal flexor retinaculum has minimal volar bowing. TH – Line drawn from tubercle of trapezium to hook of hammate. PD :The palmar displacement is line drawn perpendicular to TH and reaching till the flexor retinaculum …….. The ratio of PD/TH (15% is normal) . 14% TO 26% is taken as abnormal.
CASE REVIEW
Case of Rheumatoid arthritis with carpal tunnel syndrome.
40 YR FEMALE WITH Inflammatory arthritis ( RA) sequel