Depiction of the triangular fibro-cartilage in patients with ulnar-sided wrist pain: comparison of direct multi-slice CT arthrography and direct MR arthrography

To compare direct multi-slice CT arthrography (MSCT-AG) and direct MR arthrography (MR-AG) of the wrist with regard to the depiction of the triangular fibro-cartilage (TFC). Fifteen consecutive patients with ulnar-sided wrist pain suspicious for TFC tear underwent both MSCT-AG and MR-AG of the wrist. Images obtained were evaluated by two radiologists in a blinded fashion for the depiction of six anatomical areas (radial, central and ulnar portion on the proximal and distal side) of the TFC by means of a five-point scoring system (1 = excellent visibility to 5 = not visible). Scores for MSCT-AG and MR-AG were compared using the Student's t-test. Mean scores for MSCT-AG and MR-AG, respectively, were 2.5/2.0, 3.2/2.5 and 2.8/2.4 for the radial, central and ulnar portion of the TFC on its proximal side, and 2.7/2.0, 3.1/2.3 and 2.9/2.4 for the radial, central and ulnar portion on its distal side (n = 15). Paired Student's t-test showed no significant difference between MSCT-AG and MR-AG (P > 0.05). In a first, small series, depiction of the TFC with MSCT-AG is comparable to that of MR-AG. Further evaluation of direct multi-slice CT arthrography of the wrist in a larger patient population would be promising.     

The scapholunate interosseous ligament in MR arthrography of the wrist: correlation with non-enhanced MRI and wrist arthroscopy

 Objective. To compare three-compartment MR wrist arthrography with non-enhanced MRI in correlation with wrist arthroscopy, and to evaluate the potential of MR arthrography for consistently visualizing all parts of the scapholunate interosseous ligament of the wrist (SLIL) and exactly diagnosing the site and extent of SLIL defects. Design and Patients. In 41 patients with wrist pain (34 patients with wrist pain for more than 6 months) plain radiographs, stress views, non-enhanced MRI and three-compartment MR arthrography were done within 2 h of each other, using three-dimensional volume acquisition (0.6–1.0 mm effective slice thickness) with a gradient-recalled echo sequence and a 1.5-T magnet. The MR arthrography findings were compared with the findings from non-enhanced MRI and correlated with the arthroscopic findings in all patients. Results. The dorsal, central and palmar segments of the SLIL could be delineated exactly by MR arthrography in 95% of the patients; with non-enhanced MRI only 28% of SLIL segments were seen consistently. Demonstration of SLIL defects was possible with high diagnostic confidence in 42% of SLIL segments by non-enhanced MRI and in 94% by MR arthrography. With wrist arthroscopy as the standard of reference, sensitivity and specificity values for SLIL perforations were 52%/34% for non-enhanced MRI and 90%/87% for MR arthrography. Conclusions. MR arthrography, using three-dimensional volume acquisition with thin slices (0.6–1.0 mm), combines the advantages of three-compartment arthrography and non-enhanced MRI. It shows the precise location and magnitude of ligamentous defects of all parts of the SLIL, correlates well with wrist arthroscopy and has potential implications for diagnosis and treatment planning.     

MR直接关节造影在腕三角纤维软骨复合体损伤中的应用

目的 通过与腕关节镜结果对照,探讨MR直接关节造影在腕三角纤维软骨复合体(TFCC)损伤中的作用.方法 14例临床怀疑腕TFCC损伤的患者接受了常规MRI和MR直接关节造影,其中10例行腕关节镜检查.MR直接关节造影在腕拇长伸肌腱与伸指总肌腱间隙(相当于桡舟关节间隙)处进针,注入5～7 ml的钆喷替酸葡甲胺(0.1 mmol/L)混合液(0.3 ml钆喷替酸葡甲胺+100 ml生理盐水),与腕关节镜结果相对照,分析常规MRI和MR直接关节造影表现.结果 (1)14例中TFCC尺侧撕裂5例,桡侧撕裂4例,整体损伤5例(包括2例长期类风湿关节炎).(2)在脂肪抑制序列(STIR)及T2和T1WI序列上,损伤的TFCC表现为高信号或等信号,正常的低信号部分或完全消失,MR直接关节造影显示4例桡侧撕裂在腕TFCC的下尺桡关节和5例尺侧撕裂在尺骨茎突附着处可见不同程度的高信号对比剂聚集,5例整体损伤在下尺桡关节和尺骨茎突附着处均可见对比剂.MR直接关节造影表现与腕关节镜结果在损伤部位相符合,包括4例桡侧撕裂,3例尺侧撕裂和3例整体损伤.(3)14例腕TFCC损伤患者,8例伴有下尺桡关节半脱位,6例伴有尺桡骨骨挫伤,常规MRI和MR直接关节造影均可清晰地显示其滑膜反应和骨髓水肿等表现.结论 MR直接关节造影可以清晰地显示腕TFCC损伤,同时与常规MRI相结合能显示伴随的滑膜反应和骨髓水肿.     

Work in progress: postarthrography computed tomography of the wrist: evaluation of the triangular fibrocartilage complex

This report reviews a work in progress evaluating the use of postarthrography computed tomography (CT) of the wrist in assessing triangular fibrocartilage complex abnormalities. Twenty-two triangular fibrocartilage complex perforations in 119 patients were identified with both multiple compartment arthrography and postarthrography CT. To obtain a double contrast image of the triangular fibrocartilage complex, the postarthrography CT examinations were performed after multiple compartment arthrography and the injection of air into the radiocarpal compartment. The site of triangular fibrocartilage complex perforation could be identified (radial versus peripheral) as could degenerative changes and internal derangements such as chondrocalcinosis. We did not, however, find any information not provided by arthrography that would have changed the course of management. At this time there is no clinical role for postarthrography CT in the evaluation of triangular fibrocartilage complex derangements.     

Ultra-high resolution C-Arm CT arthrography of the wrist: Radiation dose and image quality compared to conventional multidetector computed tomography

ObjectiveObjective of this phantom and cadaveric study was to compare the effective radiation dose (ED) and image quality (IQ) between C-arm computed tomography (CACT) using an ultra-high resolution 1 × 1 binning with a standard 16-slice CT (MDCT) arthrography of the wrist.MethodsED was determined with thermoluminescence dosimetry using an anthropomorphic phantom and different patient positions. Imaging was conducted in 10 human cadaveric wrists after tri-compartmental injection of diluted iodinated contrast material and a wire phantom. IQ of MDCT was compared with CACT reconstructed with a soft (CACT1) and sharp (CACT2) kernel. High and low contrast resolution was determined. Three radiologists assessed IQ of wrist structures and occurrence of image artifacts using a 5-point Likert scale.ResultsED of MDCT was comparable to standard CACT (4.3 μSv/3.7 μSv). High contrast resolution was best for CACT2, decreased to CACT1 and MDCT. Low contrast resolution increased between CACT2 and MDCT (P < 0.001). IQ was best for CACT2 (1.3 ± 0.5), decreased to CACT1 (1.9 ± 0.6) and MDCT (3.5 ± 0.6). Non-compromising artifacts were only reported for CACT.ConclusionsThe results of this phantom and cadaveric study indicate that ultra-high resolution C-Arm CT arthrography of the wrist bears the potential to outperform MDCT arthrography in terms of image quality and workflow at the cost of mildly increasing image artifacts while radiation dose to the patient is comparably low for both, MDCT and C-Arm CT.     

MDCT arthrography of the wrist: Diagnostic accuracy and indications

Purpose

To evaluate the diagnostic accuracy and indications of arthrography with Multidetector Computed Tomography (arthro-MDCT) of the wrist in patients with absolute or relative contraindications to magnetic resonance imaging (MRI) studies and in patients with periarticular metal implants using diagnostic arthroscopy as the gold standard.

Materials and methods

After intra-articular injection of iodixanol and volumetric acquisition, 43 wrists in patients of both genders (18 females, 25 males, age range 32-60 years) were examined with a 16-detector-row CT scanner. Fifteen patients had prior wrist surgery. The patients had arthralgia, degenerative and traumatic arthropathies as well as limited range of motion, but no radiologically detected fractures. All examinations were interpreted by two experienced musculoskeletal radiologists.The findings were compared with arthroscopic findings carried out within 28 days of the CT study.

Results

In non-operated and operated wrists the comparison between arthro-MDCT and arthroscopy showed sensitivity, specificity and accuracy ranging between 92% and 94% for triangular fibrocartilage complex (TFCC), between 80% and 100% for intrinsic ligaments located within the proximal carpal compartment, and between 94% and 100% for articular cartilage.Inter-observer agreement between two radiologists, in the evaluation of all types of lesions, was almost perfect (k = 0.96) and statistically significant (p < 0.05).

Conclusions

Arthro-MDCT of the wrist provides an accurate diagnosis to identify chondral, fibrocartilaginous and intra-articular ligament lesions in patients who cannot be evaluated by MRI, and in post-surgical patients.     

Tuberculous tenosynovitis of the wrist: MRI findings in three patients

 We report recent MRI findings in patients with tuberculous tenosynovitis of the wrist. Marked synovial thickening around the flexor tendons and fluid in the tendon sheath were clearly shown on MRI. Post-contrast study was useful in distinguishing the thick tenosynovium from the surrounding structures and fluid in the tendon sheath. The well-enhanced tenosynovium was also seen in the carpal tunnel in all cases. On the basis of these findings, we could easily distinguish tenosynovitis from other soft-tissue-mass lesions, such as tumors or infected ganglia. Tuberculous tenosynovitis is often not diagnosed early, and its differentiation from soft tissue tumors may be clinically difficult. MRI, particularly post-contrast study, is useful for early diagnosis of, and planning treatment for, tuberculous tenosynovitis.     

The value of multi-detector CT arthrography of the wrist joint in evaluation of ligamentous and capsular injuries in post-traumatic pain

The wrist joint is a complex joint containing several intrinsic and extrinsic ligaments that contribute to carpal stability. There is increased incidence of ligamentous/capsular injury following trauma.

Triangular fibrocartilage and intercarpal ligaments of the wrist: Does MR arthrography improve standard MRI?

The objective of this study was to assess the value of adding MR arthrography to standard MRI for patients with chronic wrist disorders. Thirty consecutive patients (age range, 19–73 years; mean, 36.2 years) were included in the investigation. The images were evaluated blindly and separately by two radiologists with regard to lesions of the scapholunate (SL) and lunotriquetral (LT) ligaments and the triangular fibrocartilage (TFC). Conventional two- or three-compartment arthrography was used as the standard of reference. For TFC lesions, standard MR images had a sensitivity of 92.3% (reader 1) and 84.6% (reader 2) and a specificity of 41.2% (reader 1) and 52.9% (reader 2). For MR arthrography, sensitivity was 84.6% (reader 1) and 84.6% (reader 2) and specificity was 88.2% (reader 1) and 100% (reader 2). For SL ligament tears, standard MRI had a sensitivity of 33.3% (reader 1) and 11.1% (reader 2) and a specificity of 47.6% (reader 1) and 57.1% (reader 2). For MR arthrography, sensitivity was 66.7% (reader 1) and 55.6% (reader 2) and specificity was 52.4% (reader 1) and 81.0% (reader 2). For LT ligament tears, standard MRI had a sensitivity of 28.6% (reader 1) and 35.7% (reader 2) and a specificity of 93.8% (reader 1) and 81.3% (reader 2). For MR arthrography, sensitivity was 35.7% (reader 1) and 23.1% (reader 2) and specificity was 93.8% (reader 1) and 94.1% (reader 2). In conclusion, the diagnostic performance of MRI in suspected lesions of the TFC and the SL and LT ligaments is improved by adding MR arthrography to the standard examination.     

Sonographic findings of the median nerve and prevalence of carpal tunnel syndrome in patients with Parkinson's disease

PURPOSE: Parkinson's disease (PD) is a chronic progressive disorder which is characterized by rest tremor, akinesia or bradykinesia and rigidity. Carpal tunnel syndrome (CTS) is caused by compression of median nerve and can occur as a result of repetitive trauma. The aim of this study was to estimate the prevalence of CTS in PD and evaluate the median nerve sonographically. MATERIALS AND METHODS: Fifty-three wrist of 29 patients with PD were included in the study according to Hoehn and Yahr (H&Y) clinical stage and divided into two groups. The first group consisted of 29 wrists of patients with mild PD (H&Y stage I-II). The second group consisted of 24 wrists of patients with severe PD (H&Y stage III-IV). Thirty-six wrists of 20 age-matched patients were used as control group. Both of the patients with PD and control group underwent sonography and electromyography (EMG). Axial sonograms of the median nerve were obtained at the level of distal radioulnar joint (level 1) and at the level of pisiform bone in the carpal tunnel (level 2). At each level, the cross-sectional area of the median nerve and flattening ratio were calculated. RESULTS: There was no significant difference for all parameters, except one parameter, between the patients with PD and control group, and also among mild and severe groups of PD and control group (p>0.05). Interestingly, amplitude of median nerve in the second finger was significantly lower in PD patients than control group within normal limits (p=0.010). Of all wrists of PD patients, 13 (24.4%) have been diagnosed as CTS and 7 (19.4%) control wrists had CTS. Median nerve cross-sectional area of CTS patients were more than 10mm(2) in 6 (46%) wrists of PD patients but in only 1 (14%) control wrist at each level. Although it was not statistically significant, there was higher cross-sectional area at each level in patients with severe PD (level 1: 10.43+/-2.30mm(2), level 2: 10.35+/-3.19mm(2)) than patients with mild PD (level 1: 9.93+/-2.61mm(2), level 2: 9.51+/-2.83mm(2)) and control group (level 1: 9.69+/-3.19mm(2), level 2: 9.07+/-3.61mm(2)). CONCLUSION: PD may pose a risk for the development of CTS due to the repetitive movement of tremor. Although sonography is not an ideal method of diagnosis for CTS, it may take our attention for indicating CTS in patients with PD especially in severe ones.     

1253个椎体经皮成形术的治疗结果及远期疗效的单中心研究

多位研究者报道经皮椎体成形术（PVT）是一项成熟的技术，但其远期疗效仍存在争议。本研究的目的在于评价经皮椎体成形术治疗有症状而经保守治疗无效的椎体骨折病人的疗效。共624例病人的1253个压缩性骨折纳入本研究。     

Tendon involvement in rheumatoid arthritis of the wrist: MRI findings

Objective. To evaluate the distribution and extent of wrist tendon alterations in patients with active rheumatoid arthritis (RA) using magnetic resonance imaging (MRI). Design and patients. Forty-three clinically active RA patients with an illness duration of less than 4 years and no clinical evidence of tendons tears were enrolled in the study. There were 10 men and 33 women, with an average age of 52 years (range 33– 63 years). MRI of both wrists, with one exception, was performed at 1.0 T using T1- and T2-weighted sequences (slice thickness 3 mm). Twelve healthy subjects (8 women, 4 men; mean age 31 years) were also evaluated as a control group. Two radiologists reviewed each of four schematic anatomical regions (volar, dorsal, ulnar, radial) for the degree of tendon and tendon sheath alterations using two progressive scales. Results. In the control group all tendons had homogeneous low signal intensity on all sequences. A small amount of fluid was found in six subjects but the diameter was always less than 1 mm. In the patient group minimal fluid (<2 mm) was found in 35 (41%) wrists, grade 2 fluid (<2>5 mm) in 26 (31%) and grade 3 fluid (>5 mm) in 24 (28%). Fifty-nine (69%) of the grade 1 changes were in the volar compartment but grade 2 involvement was evenly distributed. Grade 3 changes were most common in the dorsal compartment and combined grade 2 and 3 in the dorsal and ulnar compartments were 32 (38%) and 25 (30%) compared with 16 (18%) and 17 (20%) respectively in the volar and radial compartments. The tendons were normal (grade 0) in 47 (46%) wrists. A maximum tendon signal change (grade 1) was demonstrated in 28 wrists (32%). When associated with other individual tendons grades this grade was demonstrated in the dorsal compartment in 30 (35%) wrists, in the volar compartment in 12 (14%), in the radial compartment in 17 (20%) and in the ulnar compartment in 26 (30%). A partial tear (grade 2) was detected in 7 (8%) wrists, all involving the dorsal and ulnar compartments; five underwent surgical repair and one proved to have a complete rupture of extensor digitorum. Three (3%) had a grade 3 complete tendon tear: all of these were in extensor tendons. Surgical repair was successful in one case but two ruptured again within 3 months. Conclusions. Low grades of peritendinous effusion were more common in the volar compartment whereas moderate and high degrees of tendon sheath fluid collection and/or pannus and signs of tendonitis were more frequent in the dorsal and ulnar tendon sheaths. Received: 20 January 2000 Revision requested: 24 February 2000 Revision received: 25 October 2000 Accepted: 19 December 2000     

Usefulness of intra-articular bupivacain and lidocain adjunction in MR or CT arthrography: A prospective study in 148 patients

Purpose

To evaluate the influence of shorter- and longer-acting intra-articular anaesthetics on post-arthrographic pain.

Materials and methods

154 consecutive patients investigated by MR or CT arthrographies were randomly assigned to one of the following groups: 1 – intra-articular contrast injection only; 2 – lidocain 1% adjunction; or 3 – bupivacain 0.25% adjunction. Pain was assessed before injection, at 15 min, 4 h, 1 day and 1 week after injection by visual analogue scale (VAS).

Results

At 15 min, early mean pain score increased by 0.96, 0.24 and 0 in groups 1, 2 and 3, respectively. Differences between groups 1 &; 3 and 1 &; 2 were statistically significant (p = 0.003 and 0.03, respectively), but not between groups 2 &; 3 (p = 0.54). Delayed mean pain score increase was maximal at 4 h, reaching 1.60, 1.22 and 0.29 in groups 1, 2 and 3, respectively. Differences between groups 1 &; 2 and 2 &; 3 were statistically significant (p = 0.002 and 0.02, respectively), but not between groups 1 &; 2 (p = 0.46). At 24 h and 1 week, the interaction of local anaesthetics with increase in pain score was no longer significant. Results were independent of age, gender and baseline VAS.

Conclusion

Intra-articular anaesthesia may significantly reduce post-arthrographic pain. Bupivacain seems to be more effective than lidocain to reduce both early and delayed pain.     

Sacro-iliac joint arthrography in low back pain: feasibility of MRI guidance

Objective: Evaluation of the feasibility of MR-guidance in sacro-iliac joint arthrography in patients whose low back pain is suspected to arise from the sacro-iliac joint (SIJ). Methods and patients: Twenty patients with low back pain underwent MR-guided sacro-iliac joint arthrography. Needles made from titanium (size 20 G, MDTech, USA) were used. For image guidance a 0.23T open-configuration C arm magnet (Proview, Marconi Medical Systems, USA) with special interventional hardware and software package (I-Path 200, Marconi Medical Systems) containing an MR compatible in-room console, large-screen (36″) display, optical navigator and accompanying software with dedicated sequences was used. No other image guidance modalities were used. Results: MR-guided SIJ arthrography was successfully performed in all twenty patients without complications. The optimal imaging sequence both for preoperative and intraoperative images was 3D-Gradient Echo sequence. The dispersal of the injected saline and anaesthetic could be determined inside the joint in all cases with heavily T2-weighted fast spin echo sequence. In the present study, 60% of the patients had significant reduction of pain after sacro-iliac joint arthrography and sacro-iliac joint was considered to be the source of patients low back pain in these patients. Conclusion: The present study shows that MR guidance with open configuration low field scanner is an accurate guiding method for sacro-iliac joint arthrography.     

Intra-articular distribution pattern after ultrasound-guided injections in wrist joints of patients with rheumatoid arthritis

Objective

To investigate the distribution of an ultrasound-guided intra-articular (IA) injection in the wrist joint of patients with rheumatoid arthritis (RA).

Methods

An ultrasound-guided IA drug injection into the wrist joint was performed in 17 patients with 1 ml methylprednisolone (40 mg/ml), 0.5 ml Lidocaine^® (5 mg/ml) and 0.15 ml gadolinium (Omniscan 0.5 mmol/ml). The drug solution was placed in the central proximal part of the wrist between the distal radius and the lunate bone. Coronal and axial MRI sequences were performed after the injection to visualize the distribution. Carpal distribution (radio-carpal, inter-carpal, and carpo-metacarpal) as well as radio-ulnar distribution was recorded. Full distribution in one compartment was given the value 1, partial distribution 0.5 and no distribution 0. A sum of the total distribution for all four compartments was calculated and correlated to the clinical parameters and the MRI OMERACT scores.

Results

No uniform pattern was seen in the distribution of the contrast. Only two patients had full contrast distribution to all four compartments, and the mean distribution count for all patients was 2.4 (range 0.5–4). The distribution count correlated with the MRI OMERACT synovitis score (r = 0.60, p = 0.014), but not with the erosions, bonemarrow oedema scores or any clinical parameters.

Conclusion

The distribution of contrast on MRI showed patient specific and random patterns after IA injections in active RA wrist joints. The degree of distribution increased with the MRI synovitis score, while no association was found with the erosion- and bonemarrow oedema score. These results indicate that a single injection into a standard injection site in the proximal part of the wrist cannot be assumed to distribute – and treat – the whole joint.     

Sonography of the finger flexor and extensor system at the hand and wrist level: findings in volunteers and anatomical correlation in cadavers

We present a review of sonography of the flexor and extensor system of the hand and wrist in volunteers and cadavers. CT tenography also was performed in cadaveric specimens. Anatomical structures of the extensor system that were assessed with sonography included the extensor tendons and insertions, retinaculum, and dorsal hood. On the flexor side, the variable relationship between the flexor superficialis and profundus could be appreciated. Volar plates, tendon insertions, and annular pulleys could also be investigated. Sonography can show details of the finger flexor and extensor system.     

Diagnosis of superior labral lesions: comparison of noncontrast MRI with indirect MR arthrography in unexercised shoulders

Objective To prospectively compare the accuracy of noncontrast magnetic resonance imaging (MRI) with indirect MR arthrography (I-MRa) of unexercised shoulders for diagnosis of superior glenoid labral lesions. Materials and methods Institutional Review Board approval and patient informed consent were obtained for this prospective study. Superior labral findings on shoulder MRI and unexercised I-MRa studies of 104 patients were correlated with findings at arthroscopic shoulder surgery. Two musculoskeletal radiologists independently reviewed the two sets of MR images while blinded to arthroscopic results. For each radiologist, the McNemar test was used to detect statistically significant differences between techniques. Results The superior labrum was intact in 24 and abnormal in 80 subjects. For detection of superior labral lesions by each radiologist, I-MRa was more sensitive (84–91%) than MRI (66–85%), with statistically significant improvement in sensitivity for one reader (p = 0.003). However, I-MRa was less specific (58–71%) than MRI (75–83%). Overall, accuracy was slightly improved on I-MRa (78–86%) compared with MRI (70–83%), but this difference was not statistically significant for either reader. Conclusion Compared with noncontrast MRI, I-MRa was more sensitive for diagnosis of superior glenoid labral lesions. However, the diagnostic value of I-MRa in shoulders remaining at rest is potentially limited by decreased specificity of the technique. The opinions and assertions contained herein are the private views of the authors and are not to be construed as official or as reflecting the views of the Department of the Army or the Department of Defense.     

3-T direct MR arthrography of the wrist: Value of finger trap distraction to assess intrinsic ligament and triangular fibrocartilage complex tears

Purpose

To determine the value of applying finger trap distraction during direct MR arthrography of the wrist to assess intrinsic ligament and triangular fibrocartilage complex (TFCC) tears.

Materials and methods

Twenty consecutive patients were prospectively investigated by three-compartment wrist MR arthrography. Imaging was performed with 3-T scanners using a three-dimensional isotropic (0.4 mm) T1-weighted gradient-recalled echo sequence, with and without finger trap distraction (4 kg). In a blind and independent fashion, two musculoskeletal radiologists measured the width of the scapholunate (SL), lunotriquetral (LT) and ulna-TFC (UTFC) joint spaces. They evaluated the amount of contrast medium within these spaces using a four-point scale, and assessed SL, LT and TFCC tears, as well as the disruption of Gilula's carpal arcs.

Results

With finger trap distraction, both readers found a significant increase in width of the SL space (mean Δ = +0.1 mm, p ≤ 0.040), and noticed more contrast medium therein (p ≤ 0.035). In contrast, the differences in width of the LT (mean Δ = +0.1 mm, p ≥ 0.057) and UTFC (mean Δ = 0 mm, p ≥ 0.728) spaces, as well as the amount of contrast material within these spaces were not statistically significant (p = 0.607 and ≥0.157, respectively). Both readers detected more SL (Δ = +1, p = 0.157) and LT (Δ = +2, p = 0.223) tears, although statistical significance was not reached, and Gilula's carpal arcs were more frequently disrupted during finger trap distraction (Δ = +5, p = 0.025).

Conclusion

The application of finger trap distraction during direct wrist MR arthrography may enhance both detection and characterisation of SL and LT ligament tears by widening the SL space and increasing the amount of contrast within the SL and LT joint spaces.