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

affecting Distal Radioulnar / Radiocarpal / intercarpal joint spaces, Articular / subarticular surfaces. ( synovial cysts, marginal erosions, synovial thickening )

Carpal tunnel syndrome. Edema in the carpal tunnel space , Volar bowing of the flexor Retinaculum , Flattening of the median nerve , Tenosynovitis.

BULKY MEDIAN NERVE WITH SIGNIFICANT

VOLAR BOWING OF THE FLEXOR RETINACULUM.

FLUID ALONG FLEXOR TENDONS- TENOSYNOVITIS

ONE OF THE COMMON CAUSES OF THE CARPAL

TUNNEL SYNDROME

EROSION / DESTRUCTION ALONG THE ARTICULAR , SUBARTICULAR LOCATIONS INVOLVING CARPAL

BONES , DISTAL RADIUS. APPRECIATED CHONDRAL THINNING , EROSIONS , SURFACE IRREGULARITY ALONG ARTICULAR MARGINS

CASE 2 – CARPAL TUNNEL SYNDROME

• 30 yr old female with MR findings supportive of CARPAL TUNNEL SYNDROME with important features as

1. Tenosynovitis along flexor tendons.2. Bulky , indentated median nerve with

relatively increased intrasubstcnace signal.3. Small articular / subarticular erosion /

irregularities of the carpal bones.4. Synovial thickening of especially along the

intercarpal joints.5. Synovial cysts as detailed in text above.6. To R/o INFLAMMATORY ARTHRITIS SEQUAEL

( RHEUMATOID ARTHRITIS) AS POSSIBILITY.

BULKY MEDIAN NERVE WITH SIGNIFICANT VOLAR BOWING OF THE FLEXOR

RETINACULUM

SYNOVIAL CYSTS IN RELATION TO THE DORSAL

ASPECT OF THE FLEXOR TENDONS.

ASSESMENT OF THE CARPAL TUNNEL WITH ULTRASOUND

FASCICULATED APPEARANCE OF THE MEDIAN NERVE

ULTRASOUND – Non invasive , No radiation , cost effective , Good for corelation.

FLUID ALONG THE TENDONS IN THE CARPAL TUNNEL

MEDIAN NERVE

FLUID ALONG THE TENDONS IN THE CARPAL TUNNEL

MEDIAN NERVE

CARPAL TUNNEL SAGITTAL VIEW.

FLEXOR TENDONS IN THE CARPAL TUNNEL – SAGITTAL PLANE