Quantitative MRI analysis of anatomic dimensions of the carpal tunnel in women

Carpal Tunnel Anthropometrics Using Acrylic Casts: A Cadaveric Study With Implications for Carpal Tunnel Release

BACKGROUND

Abundant literature exists on the morphology of the carpal tunnel. Despite this, the shape of the carpal tunnel has been reported erratically, and most studies did not attempt to correlate findings with measurements taken from cadavers. The objective of this study was to perform a morphological analysis, determine the shape and mean dimensions of the carpal tunnel, determine the level of the narrowest area of the tunnel, and establish a set of values capable of serving as a reference for carpal tunnel release.

METHODS

The carpal tunnels of 20 fresh cadaveric hands were dissected, and acrylic casts were created and measured using industrial computed tomography.

RESULTS

Of the 20 casts, 19 were shaped like elliptic cylinders, with little variation in their measurements along the length. The location of the narrowest section of the carpal tunnel is very different among casts, and the length of the roof of the carpal tunnel ranged from 21.26 to 29.86 mm.

CONCLUSIONS

The most common shape of the carpal tunnel is an elliptic cylinder. Because of the unpredictability of the location of the narrowest area of the carpal tunnel, carpal tunnel release must continue through all extension of its roof. We advise that the release should rarely be extended distally more than 30 mm from the distal palmar wrist crease, which corresponds, in most cases, to the middle of the pisiform.

Ligament and Bone Arch Partition of the Carpal Tunnel by Three-Dimensional Ultrasonography

The carpal tunnel is geometrically irregular due to the complex composition of many carpal bones intercalated by numerous intercarpal ligaments. The purpose of the study was to investigate the relative contributions of the ligament and bone arches to carpal tunnel space at the proximal, middle, and distal tunnel regions. A catheter ultrasound probe acquired fan-like images inside cadaveric carpal tunnels for three-dimensional reconstruction of the tunnel. The total tunnel volume was 5367.6 ± 940.1 mm3 with contributions of 12.0%, 6.9%, and 4.1% by proximal, middle, and distal ligament arches, respectively, and 27.0%, 25.3%, and 24.7% by proximal, middle, and distal bone arches, respectively. The bone arch occupied more tunnel space than the ligament arch at all regions (p < 0.05). The ligament arch was largest at the proximal region of the tunnel and significantly decreased toward the distal region (p < 0.05). However, the bone arch significantly decreased only from the proximal to middle region (p < 0.05) but not from the middle to distal region (p = 0.311). Consequently, it was observed that the ligament arch was the key contributor to the unequal carpal tunnel space across regions. Partitional and regional tunnel morphometric information may provide a better understanding of tunnel abnormality associated with various wrist pathological conditions. The developed framework of ultrasonography and data processing can be applied to other areas of interest in the musculoskeletal system.

The Effect of Hamatum Curvature Angle on Carpal Tunnel Volumetry: A Mathematical Simulation Model

In carpal tunnel volume measurements, the angle of the hamatum curvature is not considered a variable, and its effect on carpal tunnel volume has not been investigated. We hypothesize that a change in the anatomical angle of the hamatum curvature changes the carpal tunnel volume. To prove our hypothesis, we used a mathematical simulation model considering the carpal tunnel as a truncated cone. We reviewed the wrist CT scans of 91 adults (>18 years of age), including 51 men and 40 women. We measured the angle of the hamatum curvature in the CT scans. We measured cross-sectional areas at the outlet of the carpal tunnel at the level of the trapezium and hook of hamate (r1) and at the inlet at the level of the scaphoid and pisiform (r2) and the length (h) of the carpal tunnel. We attempted to calculate the effect of 2 degree by 2-degree changes in the angle of the hamatum curvature between the angles of 98° and 140° on the carpal tunnel volume. The mean angle of the hook of hamatum of the subjects was 122.55° ± 8.20° (range, 97.20° − 139.31°). No suitable cutoff point was found for the angle values. There was no difference between the gender groups according to the angle value. The data clearly show that there is a high correlation between carpal tunnel volume and the angle of hamatum curvature. The results of our study emphasize the importance of taking into account the anatomical features of the hamatum bone, especially the angle of curvature, which may play a predisposing role in idiopathic carpal tunnel syndrome.

Carpal tunnel and median nerve volume changes after tunnel release in patients with the carpal tunnel syndrome: a magnetic resonance imaging (MRI) study

PURPOSE

Our aim was to study the dynamics of the post-surgical canal and nerve volumes and their relationships to objective [electromyoneurography (EMNG)] and subjective (pain) outcomes.

METHODS

Forty-seven patients with carpal tunnel syndrome (CTS) (median age 52, range 23-75 years) with a prominent narrowing of the median nerve within the canal (observed during carpal tunnel release) were evaluated clinically using EMNG and magnetic resonance imagining (MRI) before and at 90 and 180 days post-surgery.

RESULTS

Canal and nerve volumes increased, EMNG findings improved and pain resolved during the follow-up. Increase in tunnel volume was independently associated with increased nerve volume. A greater post-surgical nerve volume was independently associated with a more prominent resolution of pain, but not with the extent of EMNG improvement, whereas EMNG improvement was not associated with pain resolution.

CONCLUSIONS

Data confirm that MRI can detect even modest changes in the carpal tunnel and median nerve volume and that tunnel release results in tunnel and nerve-volume increases that are paralleled by EMNG and clinical improvements. Taken together, these observations suggest that MRI could be used to objectivise persistent post-surgical difficulties in CTS patients. Level of evidence 3 (follow-up study).

Idiopathic Carpal Tunnel Syndrome: Evaluation of the Depth of the Carpal Tunnel by Ultrasonography

The objective of the work described here was to evaluate the depth of the carpal tunnel (DCT) in patients with idiopathic carpal tunnel syndrome (CTS) and healthy volunteers by ultrasonography (US), through measurement of the distance from the flexor retinaculum to the surface of the capitate bone at the carpal tunnel outlet, and compare it with other ultrasonographic and electrophysiologic parameters in CTS. The study was conducted in 60 non-diabetic patients with idiopathic carpal tunnel syndrome (unilateral n = 37, bilateral n = 23) evidenced by electrophysiologic diagnosis according to the criteria of the American Association of Electrodiagnostic Medicine (AAEM). Furthermore, 40 hands from 20 healthy volunteers were examined. Median nerve cross-sectional area (CSA); flattening ratio (FR), the ratio of the length to the width of the median nerve; and DCT at the canal outlet were measured for all participants. The mean age was 35.6 ± 9.48 y. The female-to-male ratio was 47:13 in the CTS patients. The sensitivity and specificity were 82% and 95% for CSA, 75% and 60% for FR and 75% and 87.5% for DCT, respectively. Differences between patients and healthy controls were significant for all three parameters, greatest for DCT, followed by CSA and then FR. We conclude that DCT increased in CTS and this new parameter is comparable in sensitivity and specificity to CSA and FR. DCT increased independently of the cause of the CTS (decrease in size of canal or increase in contents).

Median nerve behavior at different wrist positions among older males

The effect of wrist flexion-extension on the median nerve appearance, namely the cross-sectional area (MNCSA) and the longitudinal (D1) and vertical (D2) diameters, was investigated among older adults (N = 34). Ultrasound examination was conducted to examine the median nerve at different wrist angles (neutral; and 15°, 30°, and 45° extension and flexion), in both the dominant and nondominant hand. Median nerve behavior were significantly associated with wrist angle changes. The MNCSA at wrist flexion and extension were significantly smaller (P < .001) compared with the neutral position in both the dominant and nondominant hand. The D1 and D2 were significantly reduced at flexion (P < .001) and extension (P < .001), respectively, in both the dominant and nondominant hand. Our results suggest that a larger flexion-extension angle causes higher compression stress on the median nerve, leading to increased deformation of the MNCSA, D1, and D2 among older adults.

The effect of low- and high-velocity tendon excursion on the mechanical properties of human cadaver subsynovial connective tissue

Fibrosis of the subsynovial connective tissue (SSCT) in the carpal tunnel is the most common histological finding in carpal tunnel syndrome (CTS). Fibrosis may result from damaged SSCT. Previous studies found that with low-velocity (2 mm/s), tendon excursions can irreversibly damage the SSCT. We investigated the effect of tendon excursion velocity in the generation of SSCT damage. Nine human cadaver wrists were used. Three repeated cycles of ramp-stretch testing were performed simulating 40%, 60%, 90%, and 120% of the middle finger flexor tendon superficialis physiological excursion with an excursion velocity of 60 mm/s. Energy and force were calculated and normalized by values obtained in the first cycle for each excursion level. Data were compared with low-velocity excursion data. For high-velocity excursions, a significant drop in the excursion energy ratio was first observed at an excursion level of 60% physiological excursion (p < 0.024) and that for low-velocity excursions was first observed at 90% physiological excursion (p < 0.038). Furthermore, the energy ratio was lower at 60% for high velocities (p ≤ 0.039). Increasing velocity lowers the SSCT damage threshold. This finding may be relevant for understanding the pathogenesis of SSCT fibrosis, such as that accompanying CTS, and a relationship with occupational factors.

The effect of transverse carpal ligament lengthening on carpal tunnel volumetry: a comparison between four techniques

Transverse carpal ligament (TCL) reconstruction after open carpal tunnel release has been advocated to restore wrist kinematics and grip strength. This study investigates the effect of TCL reconstruction in carpal tunnel volume (CTV). Thirty-eight cadaveric wrists were volarly approached and TCL was exposed to its proximal and distal edges. Carpal tunnel contents were removed and the CTV was measured considering that carpal tunnel resembled the shape of a truncated cone. TCL was then dissected and subsequently reconstructed by using 4 different surgical lengthening techniques. Three of these techniques were retrieved from the literature. The fourth was proposed and performed by the authors. Postreconstruction calculation of CTV was done with the same method. In 6 cadavers, a magnetic resonance imaging-based measurement of CTV was performed to assess the validity and reliability of simulation method. The average increase of CTV ranged from 31% to 44% (P < 0.001 for all techniques). However, no statistical significant difference was found between the 4 techniques (P = 0.097). Magnetic resonance imaging volumetric values were equal to simulation measured values before and after reconstruction of TCL (P = 0.224 and P = 0.674, respectively). Lengthening of TCL substantially increases the carpal tunnel capacity regardless the applied surgical technique. The simulation model method seems to be an accurate, precise, and cost-effective approach for the evaluation of CTV.

MRI of the median nerve and median artery in the carpal tunnel: prevalence of their anatomical variations and clinical significance

OBJECTIVE

Anatomical variations of the median nerve and the persistent median artery (PMA) in the carpal tunnel (CT) are important to understand for their clinical and surgical significance. The aim of this cohort retrospective study was to investigate the prevalence of aberrant median nerve branches and persistent median artery in the CT in a selected population using magnetic resonance imaging (MRI).

MATERIALS AND METHODS

MR wrist images of 194 patients, 77 males and 117 females, aged 12-80 years were randomly selected and retrieved from our clinical and radiology data base. The MR examinations were performed using either 1.5-T or 3.0-T magnet using a cylindrical receive-transmit wrist coil for all cases. The course of the bifurcation of the median nerve was followed on axial T2-weighted and axial proton density fat saturated images and classified as either proximal, within, or distal to the CT. The flexor retinaculum proximally and the metacarpal bases were used as anatomic landmarks to subdivide these three categories. In addition, the median artery was searched in order to assess the prevalence of its presence inside the CT. A total of 194 wrists were analyzed by two musculoskeletal-trained radiologists. They were blinded on the population age, gender, and the sides of the wrists. Agreement was reached by consensus.

RESULTS

Among the 194 wrists, there was bifurcation of the nerve proximal to the CT in 12 (6.1%) wrists. There was nerve bifurcation within the CT in 36 (18%) wrists. Nerve bifurcation distal to the CT was more frequently observed, occurring in 147 (75%) wrists. Only one nerve trifurcation was seen within the CT. There was no gender predominance for the nerve bifurcation within the tunnel. There were 107 right wrists and 87 left wrists. On the right side, bifurcation of the nerve within the CT was seen in 21 (19.6%) wrists; and on the left side bifurcation of the nerve was present in 15 (17.2%) wrists. Statistically, we found no significant difference in the prevalence of the bifid nerve within the tunnel in the subgroups based on age, gender, or side of the wrists. A persistent median artery (PMA) within the tunnel was observed in 21 (11%) wrists--10 males and 11 females. Of these, four (19%) cases were presented with coexistent PMA and bifid median nerve within the tunnel. Statistically, we found that the two variations are not independent traits, and their covariance is not null.

CONCLUSION

There was a high prevalence of bifid median nerve (19%) and PMA (11%) within the tunnel regardless of gender or age. The PMA was more frequent on the left side.

The effect of landmarks and bone motion on posture-related changes in carpal tunnel volume

BACKGROUND

Deviated wrist postures have been linked to carpal tunnel syndrome development, yet the effect of posture on carpal tunnel volume remains unclear. The purposes of this study were (i) to evaluate the effect of boundary definitions on tunnel volume estimates in neutral and non-neutral (30 degrees flexion, 30 degrees extension) wrist postures and (ii) to develop a biomechanical wrist simulation to predict posture-related changes in tunnel volume.

METHODS

Two carpal tunnel volume measures were calculated using (i) ulnar bony landmarks and (ii) radial and ulnar bony landmarks identified directly from magnetic resonance imaging (MRI) scans. A third volume measure combined computerized tunnel reconstructions with modelled bone surfaces to calculate an anatomically landmarked volume. Six individual simulations were then generated to predict volume in the flexed and extended postures based on individual carpal bone motions.

FINDINGS

Boundary definitions influenced the absolute volume in each posture and the relative changes between postures. Relative to fully reconstructed volumes, radial and ulnar landmarked volumes were 15-25% larger across postures (681 (SD 467) mm(3); P=0.01), while the ulnar-only landmarked volumes were 10-20% smaller (562 (343) mm(3); P<0.01). Simulation predicted volumes were not significantly different from the reconstructed anatomically landmarked volumes, with less inter-individual variability between postures compared to MRI-based volumes.

INTERPRETATION

Comparison of volume measures indicated the importance of capturing posture-related changes in the orientation of the proximal and distal tunnel boundaries, and revealed potential sources of error associated with volume reconstruction. Simulations can enable changes in tunnel dimensions to be related to bone movements throughout a range of motion.

Wrist and carpal tunnel size and shape measurements: effects of posture

BACKGROUND

Wrist anthropometrics and posture have been implicated in the development of carpal tunnel syndrome, yet it remains unclear how external measurements relate to carpal tunnel parameters in neutral and non-neutral postures. The purposes of this study were (i) to evaluate the effect of slice orientation on several indices of carpal tunnel size and shape and (ii) to examine the relationship between carpal tunnel and external wrist dimensions.

METHODS

Three-dimensional static models were generated to measure carpal tunnel and wrist parameters for six wrists in three wrist postures (30 degrees flexion, neutral and 30 degrees extension). A simulated imaging plane enabled measurement of four carpal tunnel dimensions and two shape indices throughout the tunnel length, using "axial" and "tunnel" slice orientations (perpendicular to forearm and tunnel, respectively).

FINDINGS

Correction for tunnel orientation eliminated posture-related changes in tunnel size and shape noted at the distal end using "axial" alignment. "Tunnel" alignment reduced average carpal tunnel area and depth by nearly 15% in extension, but generally less than 5% in neutral and 2% in flexion. Subsequently, "tunnel" alignment also decreased carpal tunnel and non-circularity ratios to reveal a flatter, more elliptical shape throughout the tunnel in extension than neutral and flexion. Wrist dimensions correlated significantly with tunnel dimensions, but not tunnel shape, while wrist shape correlated significantly with tunnel shape, area and depth.

INTERPRETATIONS

Slice alignment with the carpal tunnel may improve the consistency of findings within and between patient and control populations, and enhance the diagnostic utility of imaging in clinical settings.

Magnetic resonance imaging of idiopathic carpal tunnel syndrome: correlation with clinical findings and electrophysiological investigation

OBJECTIVE

To compare clinical evaluation, electrophysiological investigation and magnetic resonance findings in assessing the severity of idiopathic carpal tunnel syndrome.

PATIENTS AND METHODS

Seventy-four patients with idiopathic carpal tunnel syndrome were prospectively recruited. Clinical evaluation included symptoms severity score and two-point discrimination, sensory and motor nerve conduction velocities were determined by electroneuromyography and imaging parameters were obtained after wrist magnetic resonance. The Wilcoxon test was used to define the differences between measurements of median nerve area. The Pearson and Spearman correlation tests were used to determine the relationships between all the measured parameters.

RESULTS

Cross-sectional area of median nerve was smaller at hamate level than at radio-ulnar joint and pisiform levels (p<0.001). With exception of median nerve area at hamate level, there was a lower degree of correlation between MRI parameters and findings obtained by clinical assessments and electrophysiological measurements. The median nerve area at hamate level correlated negatively with duration of symptoms, two-point discrimination, symptoms severity score and positively with sensory nerve conduction velocity (p<0.01).

CONCLUSION

In patients with idiopathic carpal tunnel syndrome, median nerve area measured by wrist magnetic resonance at hamate level may be considered as a valuable indicator to grading the severity of disease.

The role of magnetic resonance imaging in the early diagnosis of rheumatoid arthritis

Rheumatoid arthritis (RA) is a common disease that affects 1% of the population. With the advent of disease-modifying therapies, it became particularly important to detect RA as early as possible. In this article, we discuss the role of magnetic resonance imaging (MRI) in the imaging of early RA. Imaging of soft tissues manifestations, which precede the development of osseous erosions, is discussed. We also review the role of MRI in establishing correct diagnosis in cases of arthritis, which do not demonstrate classical clinical presentation. The role of MRI in the follow-up of RA is addressed.

Evaluation of the carpal tunnel based on 3-D reconstruction from MRI

While deviated wrist postures have been linked to the development of carpal tunnel syndrome, the relative contributions of posture-related changes in size, shape and volume of the carpal tunnel contribute to median nerve compression are unclear. The purpose of this study was two-fold: (1) to reconstruct the carpal tunnel from MRI data in neutral and non-neutral (30 degrees extension, 30 degrees flexion) wrist postures, and (2) to evaluate errors associated with off-axis imaging. Three-dimensional reconstruction of the carpal tunnels of 8 volunteers from the university community revealed that the orientation of the carpal tunnel was not directly explained by external wrist angle. The average orientation of the carpal tunnel was extended in all postures, ranging from 25 degrees +/-9 degrees in extension, 13 degrees +/-5 degrees in neutral and 4 degrees +/-4 degrees in the flexed wrist. Changing the orientation of the imaging plane to be perpendicular to the reconstructed carpal tunnel revealed that axial images overestimated cross-sectional area by an average of nearly 10% in extension, 4% in neutral and less than 1% in flexion. Similarly, adjusting the imaging plane to be perpendicular to external wrist angle overestimated cross-sectional area by an average of 2% in extension, 4% in neutral and 24% in flexion. Distortion of the carpal tunnel shape also became evident with rotation of the imaging plane. The data suggest that correction for the orientation of the carpal tunnel itself to be more appropriate than relying on external wrist angle. Computerized reconstruction provided detailed anatomic visualization of the carpal tunnel, and has created the framework to develop a biomechanical model of the carpal tunnel. Similar reconstruction of the tissue structures passing through (median nerve and flexor tendons) and entering the carpal tunnel (muscle tissue) will enable evaluation and partitioning of median nerve injury mechanisms.

An MRI evaluation of carpal tunnel dimensions in healthy wrists: Implications for carpal tunnel syndrome

BACKGROUND

Deviated wrist postures and pinch grip use have been linked to the development of carpal tunnel syndrome and are likely related to the size and shape of the carpal tunnel. The purpose of this study was to quantify carpal tunnel dimensions with changes in wrist posture and pinch grip.

METHODS

Eight healthy volunteers (4 male, 4 female) underwent magnetic resonance imaging of their dominant wrists under seven conditions which included: 30 degrees wrist extension, neutral and 30 degrees flexion (with and without a 10 N pinch force) and a fist with a neutral wrist. Cross-sectional area of the carpal tunnel and its contents were calculated at 3mm increments along the length of the tunnel and integrated to calculate volumes. Ratios were calculated between the contents of the tunnel to the tunnel itself for area and volume.

FINDINGS

The use of a correction factor significantly reduced volume and distal carpal tunnel area in flexed and extended wrists. Carpal tunnel areas were largest in neutral and smallest at the distal end with wrist flexion. An extended wrist resulted in the smallest carpal tunnel and content volumes as well as the smallest carpal tunnel content volume to carpal tunnel volume ratios. While men had significantly larger areas and volumes than women for both the carpal tunnel and it contents, there were no differences in ratios between the contents and tunnel size.

INTERPRETATION

A simple correction factor for non-perpendicular magnetic resonance images proved useful in relating volume changes to known pressure changes within the carpal tunnel. More inclusive and detailed evaluation of the carpal tunnel and its contents is required to fully understand mechanisms for median nerve compression in the carpal tunnel.

Pathomechanics of peripheral nerve loading. Evidence in carpal tunnel syndrome

Peripheral nerve injury is a common occurrence, with carpal tunnel syndrome (CTS) receiving the most attention. Nerve dysfunction associated with compression syndromes results from an interruption or localized interference of microvascular function due to structural changes in the nerves or surrounding tissues. This article reviews the physiologic, pathophysiologic, and histologic effects of compressing peripheral nerves in animal models, and then examines the evidence for similar processes in humans using CTS as a model.

Ultrasonographic evaluation of age-related changes in bowing of the flexor retinaculum

The effects of age, gender, and hand dominance on bowing of the flexor retinaculum, used in diagnosing carpal tunnel syndrome, were analyzed. Forty men aged 23-58 years old (39.7 +/- 11.2) and 40 women aged 20-57 years old (39.6 +/- 11.3) were the normal subjects. A total of 160 wrists was examined with a linear array transducer. Bowing of the flexor retinaculum was measured as the distance from a line drawn between the trapezium and the hamate to the palmar apex of the outer surface of the flexor retinaculum. It was 0.5-3.7 mm (2.00 +/- 0.64) for all hands, 0.6-3.7 mm (2.06 +/- 0.62) for men, 0.5-3.4 mm (1.96 +/- 0.67) for women, 0.5-3.4 mm (1.00 +/- 0.64) for dominant, and 0.6-3.7 mm (2.03 +/- 0.65) for nondominant hands. There was no difference between genders or dominant vs non-dominant hands regarding this parameter. However, it was highly correlated with age (r=0.59, p<0.0001). In conclusion, bowing of the flexor retinaculum measurements should be carefully compared with the standardized values when diagnosing carpal tunnel syndrome.

Cross-sectional area of the carpal canal proximal and distal to the wrist flexion crease

PURPOSE

The purposes of this study were as follows: (1) to locate the position of the distal wrist flexion crease with respect to the carpal bones, specifically the proximal pole of the capitate, and (2) to determine the cross-sectional area of the carpal canal proximal and distal to the wrist flexion crease to enable us to determine whether or not there is a focal area of narrowing that would provide an anatomic basis for the proximal extent of carpal tunnel release.

METHODS

This study had 2 parts. The first part was a plain radiographic study of 21 uninjured wrists in 12 volunteers that defined the position of the distal wrist flexion crease with respect to the carpus. The second part was a magnetic resonance imaging study of 13 wrists in asymptomatic volunteers that measured the cross-sectional area of the carpal canal proximal and distal to the wrist flexion crease.

RESULTS

In 19 of 21 wrists the distal wrist flexion crease was within 2 mm of the proximal pole of the capitate. We noted a gradual increase in the area of the carpal canal moving proximal from its narrowest point. There was no significant increase in area until approximately 23 mm proximal to the narrowest point.

CONCLUSIONS

We noted no focal area of narrowing in the cross-sectional area of the carpal canal either proximal or distal to the wrist flexion crease.

Ergonomic Pain--Part 2: Differential Diagnosis and Management Considerations

Work-related musculoskeletal disorders (MSDs) can produce ergonomic pain in several different regions of the body, including the shoulder, elbow, wrist and hand, lumbar spine, knee, and ankle/foot. Each family of disorders is distinctive in presentation and requires diagnosis-specific interventions. Because of the complex nature of these disorders, management approaches may not always eliminate symptoms and or completely restore patient function to a level found prior to symptom onset. As a consequence, ergonomic measures should be implemented to reduce the overload on tissue and contribute to patient recovery. However, functional limits may persist and the clinician must make further decisions regarding a person's functional status in the chronic stages of the patient's care.

Diagnosis of carpal tunnel syndrome: electrodiagnostic and MR imaging evaluation

In clinically classic carpal tunnel syndrome (CTS) without symptoms or signs to suggest other disorders that can mimic CTS, it remains somewhat controversial as to whether performing nerve conduction studies is necessary or cost-effective. MR imaging reliably depicts normal carpal tunnel anatomy. It can also identify pathologic nerve compression and mass lesions, such as ganglion cysts, that compress nerves. Currently, MR imaging is most commonly used to image patients with ambiguous electrodiagnostic studies and clinical examinations. MR diffusion-weighted imaging of peripheral nerves might prove to be the most sensitive imaging sequence for the detection of early nerve dysfunction. Electrodiagnostic studies are likely to remain the pivotal diagnostic examination in patients with suspected CTS for the foreseeable future. With advances in both software and hardware, however, high-resolution MR imaging of peripheral nerves will become faster, cheaper, and likely more accurate, possibly paving the way for an expanded role in the diagnosis of this common syndrome.

Advanced imaging of early rheumatoid arthritis

Advances in MR imaging of arthritis include contrast-enhanced, dynamic, and quantitative imaging techniques. These advances may result in MR imaging becoming the gold standard in diagnosing early RA. MR imaging is a useful technique in diagnosis, follow-up, and evaluation of remission in rheumatic diseases of the joints. Early diagnosis of RA, in the first 6 months after the onset of symptoms, may lead to earlier control and prevent future erosions and deformities.

Does carpal canal stenosis predict outcome in women with carpal tunnel syndrome?

OBJECTIVE

We investigated the role of carpal canal stenosis as a predictor of outcome in patients who underwent surgical treatment for carpal tunnel syndrome (CTS).

METHODS

We performed magnetic resonance imaging (MRI) of the wrist in 31 female patients with clinically and neurophysiologically confirmed CTS. With a computerized analyser we quantitatively calculated the focal narrowest point of the tunnel. Patient's assessment of CTS-related symptoms were obtained by using a visual analogue scale before, and 6 months after treatment.

RESULTS

Seventeen (56%) patients improved in all symptoms after treatment. The focal narrowest point of the tunnel was identified at its distal third in all patients, at 8 mm from the outlet. The median area of the narrowest point in those who improved clinically (n=17) was 238.9 mm2 compared with 269.8 mm2 in others (n=14), P=0.046.

CONCLUSION

Identification of carpal canal stenosis may be important in selecting candidates for treatment in symptomatic CTS.