Sonoanatomy relevant for lumbar plexus block in volunteers correlated with cross-sectional anatomic and magnetic resonance images.

BACKGROUND: Ultrasound imaging of the anatomy relevant for lumbar plexus block (LPB) is challenging because of its deep anatomic location and the "acoustic shadow" of the overlying transverse processes. A paramedian transverse scan (PMTS) of the lumbar paravertebral region with the ultrasound beam being insonated through the intertransverse space (ITS) and directed medially toward the intervertebral foramen (PMTS-ITS) may overcome the problem of the "acoustic shadow" and allow clear visualization of the anatomy relevant for LPB. This study assessed the feasibility of using PMTS-ITS for imaging the anatomy relevant for LPB in healthy volunteers. METHODS: Thirty young volunteers underwent a PMTS-ITS of the right lumbar paravertebral region. The sonoanatomy was defined in corresponding cadaver anatomic sections and magnetic resonance images. Visibility of the paravertebral structures in the sonograms was assessed by 4 independent observers using a 4-point Likert scale (0, not visible; 1, hardly visible; 2, well visible; 3, very well visible), and the mean total ultrasound visibility score (UVS; maximum score possible, 30) was determined. Overall ultrasound visibility was judged as good if the total UVS was greater than 20, average if it was 10 to 20, and poor if it was less than 10. RESULTS: Ultrasound imaging of the right lumbar paravertebral region at the L3-L4-L5 vertebral level was successfully performed through the PMTS-ITS scan window in all volunteers studied. The lumbar nerve root, lumbar paravertebral space, lumbar plexus, and the psoas compartment were delineated in 57%, 27%, 57%, and 87% of volunteers, respectively. Overall ultrasound visibility of the lumbar paravertebral structures was judged as "good" (mean [SD] total UVS, 20.4 [3]). CONCLUSIONS: A PMTS-ITS can be used to image the sonoanatomy relevant for LPB including the lumbar nerve root, lumbar paravertebral space, lumbar plexus, and the psoas compartment.

Image-guided versus blind corticosteroid injections in adults with shoulder pain: a systematic review.

BACKGROUND: Corticosteroid injections can be performed blind (landmark-guided) or with image guidance, and this may account for variable clinical outcomes. The objective of this study was to assess the effectiveness and safety of image-guided versus blind corticosteroid injections in improving pain and function among adults with shoulder pain. METHODS: MEDLINE, the Cochrane Controlled Trials Register and EMBASE were searched to May 2010. Additional studies were identified by searching bibliographies of shortlisted articles. Search items included blind, landmark, anatomical, clinical exam, image-guided, ultrasound, fluoroscopy, steroid injection, frozen shoulder, random allocation, randomized controlled trial (RCT) and clinical trial.Randomized controlled studies comparing image-guided versus blind (landmark-guided) corticosteroid shoulder injections that examined pain, function and/or adverse events were included. Independent extraction was done by two authors using a form with pre-specified data fields, including risk of bias appraisal. Conflicts were resolved by discussion. The decision to pool data was based on assessment of clinical design homogeneity. When warranted, studies were pooled under a random-effects model. RESULTS: Two RCTs for pain, function and adverse events (n = 101) met eligibility criteria. No serious threats to validity were found. Both trials compared ultrasound-guided versus landmark-guided injections and were judged similar in clinical design. Low to moderate heterogeneity was observed: shoulder pain I2 = 60%, function I2 = 22%. A meta-analysis demonstrated greater improvement with ultrasound-guided injections at 6 weeks after injection in both pain (mean difference = 2.23 [95% CI: 1.27, 3.18]), as assessed with a 0 to 10 visual analogue scale, and shoulder function (standardised mean difference = 1.09 [95% CI: 0.61, 1.57]) as assessed with shoulder function scores. Although more adverse events (all mild) were reported with landmark-guided injections, the difference was not statistically significant (risk ratio = 0.20 [95% CI: 0.04, 1.13]).This review was only based on two moderate-sized trials. Blinding of patients was not performed in both trials, causing some risk of bias in outcome assessment since primary endpoints were wholly or partially patient-reported. CONCLUSION: There is a paucity of RCTs on image-guided versus landmark-guided corticosteroid shoulder injections examining pain, function and adverse events. In this review, patients who underwent image-guided (ultrasound) injections had statistically significant greater improvement in shoulder pain and function at 6 weeks after injection. Image-guided (ultrasound) corticosteroid injections potentially offer a significantly greater clinical improvement over blind (landmark-guided) injections in adults with shoulder pain. However, this apparent benefit requires confirmation from further studies (adequately-powered and well-executed RCTs).

MR-guided direct arthrography of the hip.

PURPOSE: To develop an MR-guided technique for direct magnetic resonance arthrography (DMRA) of the hip using a conventional 1.5 Tesla (T) MRI scanner. MATERIALS AND METHODS: Interactive versions of standard single-shot fast spin echo, coherent gradient echo, and fully balanced steady-state free precession sequences were developed, together with the ability to operate the scanner from within the magnet room. Initial optimization was performed using ex vivo animal joints. After informed consent, five patients underwent DMRA using dilute gadolinium as the contrast medium. RESULTS: The procedure was successful in all five patients and diagnostic quality MR arthrography studies were obtained in all cases. The time taken from the initial placement of skin marker to the introduction of contrast medium reduced with successive patients: 26, 22, and 19 min with the final two studies taking 13 min each. CONCLUSION: This work demonstrates the feasibility of performing DMRA using MR guidance, avoiding the need for X-ray fluoroscopy facilities but exploiting the available imaging performance of a high-field closed-bore MR system. The use of an in room control and display system together with interactive fluoroscopic imaging sequences simplifies the positioning of the needle and allows rapid confirmation of an intra-articular injection.

Ultrasound-guided core-needle biopsy of the testis for focal indeterminate intratesticular lesions.

The aim of this study was to evaluate ultrasound (US)-guided core-needle testicular biopsy. Twelve biopsies were performed in eleven patients, under US guidance using disposable 16- or 18-gauge needles, between April 2003 and October 2006. Details were entered on a database and records reviewed 9 months to 3 years after biopsy. Final diagnoses were based on histology of the biopsy, open surgical resection where performed, and interval follow-up. Biopsies were well tolerated and no complications were encountered apart from a single minor testicular haemorrhage. Benign histology was demonstrated on the core-needle samples of six patients and US follow-up was compatible with these diagnoses. Of five patients whose core-needle biopsies yielded malignancy, two patients had primary testicular tumours; both have been treated successfully with orchiectomy and chemotherapy. Three patients with haematological malignancies had successful chemotherapy without orchiectomy; one of these three underwent post-chemotherapy biopsy demonstrating resolution. There are four main clinical scenarios when core-needle testicular biopsy is performed in our institution: (1) lesions with equivocal malignant US features, (2) discrepancy between radiological and clinical findings, (3) suspected malignant process where orchiectomy is unnecessary, e.g. lymphoma, (4) atrophic testes, where it is frequently difficult to differentiate malignancy from the heterogeneous echo pattern.

Impact of calcification and intraluminal thrombus on the computed wall stresses of abdominal aortic aneurysm.

BACKGROUND: Increased biomechanical stresses within the abdominal aortic aneurysm (AAA) wall contribute to its rupture. Calcification and intraluminal thrombus can be commonly found in AAAs, but the relationship between calcification/intraluminal thrombus and AAA wall stress is not completely described. METHODS: Patient-specific three-dimensional AAA geometries were reconstructed from computed tomographic images of 20 patients. Structural analysis was performed to calculate the wall stresses of the 20 AAA models and their altered models when calcification or intraluminal thrombus was not considered. A nonlinear large-strain finite element method was used to compute the wall stress distribution. The relationships between wall stresses and volumes of calcification and intraluminal thrombus were sought. RESULTS: Maximum stress was not correlated with the percentage of calcification, and was negatively correlated with the percentage of intraluminal thrombus (r = -0.56; P = .011). Exclusion of calcification from analysis led to a significant decrease in maximum stress by a median of 14% (range, 2%-27%; P < .01). When intraluminal thrombus was eliminated, maximum stress increased significantly by a median of 24% (range, 5%-43%; P < .01). CONCLUSION: The presence of calcification increases AAA peak wall stress, suggesting that calcification decrease the biomechanical stability of AAA. In contrast, intraluminal thrombus reduces the maximum stress in AAA. Calcification and intraluminal thrombus should both be considered in the evaluation of wall stress for risk assessment of AAA rupture.