Thermal protection during percutaneous thermal ablation procedures: interest of carbon dioxide dissection and temperature monitoring

Percutaneous image-guided thermal ablation of tumor is widely used, and thermal injury to collateral structures is a known complication of this technique. To avoid thermal damage to surrounding structures, several protection techniques have been reported. We report the use of a simple and effective protective technique combining carbon dioxide dissection and thermocouple: CO(2) displaces the nontarget structures, and its low thermal conductivity provides excellent insulation; insertion of a thermocouple in contact with vulnerable structures achieves continuous thermal monitoring. We performed percutaneous thermal ablation of 37 tumors in 35 patients (4 laser, 10 radiofrequency, and 23 cryoablations) with protection of adjacent vulnerable structures by using CO(2) dissection combined with continuous thermal monitoring with thermocouple. Tumor locations were various (19 intra-abdominal tumors including 4 livers and 9 kidneys, 18 musculoskeletal tumors including 11 spinal tumors). CO(2) volume ranged from 10 ml (epidural space) to 1500 ml (abdominal). Repeated insufflations were performed if necessary, depending on the information given by the thermocouple and imaging control. Dissection with optimal thermal protection was achieved in all cases except two patients where adherences (one postoperative, one arachnoiditis) blocked proper gaseous distribution. No complication referred to this technique was noted. This safe, cost-effective, and simple method increases the safety and the success rate of percutaneous thermal ablation procedures. It also offers the potential to increase the number of tumors that can be treated via a percutaneous approach.

Value of diffusion-weighted imaging to detect small malignant pelvic lymph nodes at 3 T

OBJECTIVE

To investigate the usefulness of diffusion-weighted imaging (DWI) to discriminate between metastatic and non-metastatic small lymph nodes in pelvic carcinoma.

MATERIALS AND METHODS

A total of 259 patients (180 normal, 79 metastatic) prospectively underwent DWI at 3 T. We measured the short-axis diameter and the mean apparent diffusion coefficient (ADC) value. Lymph nodes with a short-axis diameter larger than 8 mm were recorded as being suspected metastatic lymph nodes. Imaging data were correlated station by station with histopathological results.

RESULTS

A total of 140 metastatic nodes were accurately matched with histology. On T2w, the short-axis diameter for non-metastatic and metastatic lymph nodes was 6.4 mm +/- 2.5 mm and 8.3 mm +/- 4.5 mm, respectively. Almost all metastatic or non-metastatic nodes had similar high signal intensity on DWI (except in 5 cases) with a homogeneous pattern. The mean ADC values (10(-3) mm(3)/s +/- standard deviation) of involved lymph nodes, control iliac nodes and control inguinal nodes were 924 +/- 217, 968 +/- 182 and 1,036 +/- 181, respectively. There were no statistically significant differences in the ADC of metastatic and non-metastatic nodes.

CONCLUSION

Isolated measurement of mean ADC values in a suspected station does not contribute to the diagnosis of metastatic nodes, in patients with small ambiguous nodes.

Diffusion-weighted MRI of denervated muscle: a clinical and experimental study

OBJECTIVE

The aim of this study was to investigate skeletal muscle denervation using diffusion-weighted magnetic resonance imaging (DWMRI).

MATERIALS AND METHODS

Sciatic nerve axotomy was performed in a group of nine New Zealand White rabbits, and electromyographic (EMG), pathological, and DWMRI studies were conducted on ipsilateral hamstring muscles 1 and 8 days after axotomy. In addition, DWMRI studies were carried out on leg muscles of ten patients with acute and subacute lumbosacral radiculopathy.

RESULTS

High intensity signals on short tau inversion recovery (STIR) magnetic resonance imaging and an increased apparent diffusion coefficient (ADC) were observed in denervated muscles of the animals 1 and 8 days after axotomy as well as in denervated muscles of the patients with radiculopathy. In the clinical study, ADC was 1.26 +/- 0.18 x 10(-9) m(2)/s in normal muscle and increased to 1.56 +/- 0.23 x 10(-9) m(2)/s in denervated muscles (p = 0.0016). In animals, EMG and muscle pathological studies were normal 1 day after axotomy, and the muscles demonstrated spontaneous activity on EMG and neurogenic atrophy on histological studies 7 days later.

CONCLUSION

This DWMRI study demonstrates that enlargement of extracellular fluid space in muscle denervation is an early phenomenon occurring several days before the appearance of EMG and histological abnormalities.

Radiofrequency and laser ablation of spinal lesions

Radiofrequency current and laser energy can be delivered locally through electrode-needle or optical fiber inserted in the tissue and allows local ablation of tissues, up to a volume of 4 to 5 cm in diameter with one application or vaporizes tissue. Tumor ablation guided with medical imaging proved a high local efficacy over 90% for tumors less than 25 mm in the liver, lung, and kidney. The spinal applications of the thermal energy of RF and laser are reported in this paper. First, the tumor ablation is reviewed with malignant and benign tumors. In malignant tumors, radiofrequency is very efficient in local tumor control and in pain management. The second part of this paper is devoted to disk diseases where laser and RF techniques increase their applications. The technique, indications and results of these techniques are reported and illustrated.

Early prediction of femoral head avascular necrosis following neck fracture

Femoral neck fracture puts at risk functional prognosis in young patients and can be life-threatening in the elderly. The present study reviews methods of femoral head vascularity assessment following neck fracture, to address the following issues: what is the risk of osteonecrosis? And what, in the light of this risk, is the best-adapted treatment to avoid iterative surgery? Femoral head vascularity depends on retinacular vessels and especially the lateral epiphyseal artery, which contributes from 70 to 80% of the femoral head vascular supply. Fracture causes vascular lesions, which are in turn the prime cause of necrosis. Other factors combine with this: hematoma tamponade effect, reduced joint space and increased pressure due to lower extremity positioning in extension/internal rotation/abduction during surgery. Head deformity is not due to direct cell death but to the repair process originating from the surrounding living bone. In post-traumatic necrosis, proliferation rapidly invades the head, with significant osteogenesis. Pathologic fractures occur at the boundary between the new and dead bone. Many techniques have been reported to help assess residual hemodynamics and risk of necrosis. Some are invasive: superselective angiography, intra-osseous oxygen pressure measurement, or Doppler-laser hemodynamic measurement; others involve imaging: scintigraphy, conventionnal or dynamic MRI. The future seems to lie with dynamic MRI, which allows a new classification of femoral neck fractures, based on a non-invasive assessment of femoral head vascularity.

In antisynthetase syndrome, ACPA are associated with severe and erosive arthritis: an overlapping rheumatoid arthritis and antisynthetase syndrome

Anticitrullinated peptide/protein antibodies (ACPA), which are highly specific for rheumatoid arthritis (RA), may be found in some patients with other systemic autoimmune diseases. The clinical significance of ACPA in patients with antisynthetase syndrome (ASS), a systemic disease characterized by the association of myositis, interstitial lung disease, polyarthralgia, and/or polyarthritis, has not yet been evaluated with regard to phenotype, prognosis, and response to treatment. ACPA-positive ASS patients were first identified among a French multicenter registry of patients with ASS. Additionally, all French rheumatology and internal medicine practitioners registered on the Club Rhumatismes et Inflammation web site were asked to report their observations of ASS patients with ACPA. The 17 collected patients were retrospectively studied using a standardized questionnaire and compared with 34 unselected ACPA-negative ASS patients in a case-control study. All ACPA-positive ASS patients suffered from arthritis versus 41% in the control group (P < 0.0001). The number of swollen joints was significantly higher (7.0 ± 5.0 vs 2.9 ± 3.9, P < 0.005), with a distribution resembling that of RA. Radiographic damages were also more frequent in ACPA-positive ASS patients (87% vs 11%, P < 0.0001). Aside from a significantly higher transfer factor for carbon monoxide in ACPA-ASS patients, lung, muscle, and skin involvements had similar incidences, patterns, and severity in both groups. Although Nonbiologic treatments were similarly used in both groups, ACPA-positive patients received biologics more frequently (59% vs 12%, P < 0.0008), mostly due to refractory arthritis (n = 9). Eight patients received anti-Cluster of differentiation 20 (CD20) monoclonal antibodies (mAbs) with good efficacy and tolerance, whereas 2 of the 5 patients treated with antitumor necrosis factor drugs had worsened myositis and/or interstitial lung disease. After a >7-year mean follow-up, extra-articular outcomes and survival were not different. ACPA-positive ASS patients showed an overlapping RA-ASS syndrome, were at high risk of refractory erosive arthritis, and might experience ASS flare when treated with antitumor necrosis factor drugs. In contrast, other biologics such as anti-CD20 mAb were effective in this context, without worsening systemic involvements.

Accuracy of delayed post-contrast flair MR imaging for the diagnosis of leptomeningeal infectious or tumoral diseases

AIMS

To compare unenhanced, gadolinium enhanced, delayed gadolinium enhanced FLAIR images, gadolinium enhanced and delayed gadolinium enhanced T1 images in different types of leptomeningeal diseases, and to determine the most accurate MRI sequence for the diagnosis of leptomeningeal disease.

MATERIAL

and methods: Ten patients (6 men, 4 women, age: 52,7+/-16,4) clinically suspected of cerebral leptomeningeal infectious or tumoral disease underwent brain MR examination: Axial FLAIR and T1 SE images were acquired before, immediately after administration of gadobenate dimeglumine (0.1 mmol per kilogram of body weight) (early enhancement), and 20 minutes after injection of contrast media (delayed enhancement). Images were analysed to determine the more appropriate technique for the diagnosis of leptomeningeal disease.

RESULTS

Early enhanced FLAIR and delayed enhanced T1 were always more or equally accurate for the diagnosis of leptomeningeal diasease, as compared to, respectively, unenhanced FLAIR and early enhanced T1 images Delayed enhanced FLAIR was always more accurate for the diagnosis of leptomeningeal disease as compared to early enhanced FLAIR images. Delayed enhanced FLAIR was in most of the cases more accurate for the diagnosis of leptomeningeal disease as compared to delayed enhanced T1 images.

CONCLUSION

Delayed enhanced FLAIR MR sequence seems to improve the diagnosis of leptomeningeal infectious or tumoral diseases as compared to other MR sequences.

Acute torsion of uterine leiomyoma: CT features

Acute torsion of a subserosal leiomyoma is a rare acute condition that is infrequently diagnosed preoperatively. It is a recognized surgical emergency, especially when additional systemic symptoms are associated. There are two main differential diagnoses: ovary/adnexal torsion and massive infarct inside a common leiomyoma. The diagnosis can be established by computed tomographic features. Ultrasound examination is less sensitive.

Septic arthritis: monitoring with USPIO-enhanced macrophage MR imaging

PURPOSE

To prospectively evaluate in vivo noninvasive monitoring of antibiotic therapy in experimental infectious arthritis by imaging macrophages by using magnetic resonance (MR) imaging enhanced with ultrasmall superparamagnetic iron oxide (USPIO) particles.

MATERIALS AND METHODS

The institutional review committee on animal care approved the experimental protocol. Unilateral knee infection was induced by intra-articular injection of Staphylococcus aureus in 12 rabbits. Each rabbit underwent MR imaging before and after injection of USPIO particles, as well as before and after injection of gadoterate meglumine. All 12 of the animals were imaged during the acute phase of infection. Half were then sacrificed to obtain histopathologic samples, and the other half were imaged a second time after antibiotic treatment. MR imaging data were analyzed and compared with bacteriologic and histopathologic findings.

RESULTS

In acute infections, intense synovitis with marked signal intensity increase of the synovium on gadoterate dimeglumine-enhanced fat-suppressed T1-weighted images was observed in all animals and was associated with areas of signal intensity loss within the infected synovium on USPIO-enhanced T2*-weighted gradient-echo images, reflecting an intense infiltration of USPIO-loaded macrophages. After antibiotic treatment and histologic evidence of healing infection, less synovial signal intensity loss was seen (P = .03). In contradistinction, the signal intensity increase on gadoterate dimeglumine-enhanced fat-suppressed T1-weighted images remained unchanged.

CONCLUSION

In contrast to conventional MR imaging performed by using extracellular contrast agents, USPIO-enhanced macrophage MR imaging can demonstrate resolution of experimental bacterial joint infection.

Contrast-to-Dose Relationship of Gadopiclenol, an MRI Macrocyclic Gadolinium-based Contrast Agent, Compared with Gadoterate, Gadobenate, and Gadobutrol in a Rat Brain Tumor Model

Background Detection of cerebral lesions at MRI may benefit from a chemically stable and more sensitively detected gadolinium-based contrast agent (GBCA). Gadopiclenol, a macrocyclic GBCA with at least twofold higher relaxivity, is currently undergoing clinical trials in humans. Purpose To determine the relationship between MRI contrast enhancement and the injected dose of gadopiclenol in a glioma rat model compared with those of conventional GBCA at label dose. Materials and Methods Between April and July 2012, 32 rats implanted with C6 glioma received two intravenous injections at a 24-hour interval. The injections were randomly selected among five doses of gadopiclenol (0.025, 0.05, 0.075, 0.1, and 0.2 mmol/kg) and three reference GBCAs (gadoterate meglumine, gadobutrol, and gadobenate dimeglumine) at 0.1 mmol/kg. MRI tumor enhancement was assessed on T1-weighted images before and up to 30 minutes after injection. Two blinded radiologists visually and qualitatively scored contrast enhancement, border delineation, and visualization of tumor morphology. Quantitatively, variations in contrast-to-noise ratio (ΔCNR) between tumor and contralateral parenchyma were calculated at each time point and were compared for each treatment at 5 minutes by using a mixed model after normality test. Results A total of 24 rats underwent the complete protocol (n = 5-7 per group). A linear dose-dependent ΔCNR relationship was observed between 0.025 and 0.1 mmol/kg for gadopiclenol (R ² = 0.99). No difference in ΔCNR was observed between the three reference GBCAs (P ≥ .55). Gadopiclenol resulted in twofold higher ΔCNR at 0.1 mmol/kg (P < .001 vs gadobutrol and gadoterate, P = .002 vs gadobenate) and similar ΔCNR at 0.05 mmol/kg (P = .56, P > .99, and P = .44 compared with gadobutrol, gadobenate, and gadoterate, respectively). For both readers, 0.05 mmol/kg of gadopiclenol improved contrast enhancement, border delineation, and visualization of tumor morphology (scores > 3 compared with scores between 2 and 3 for the marketed GBCA). Conclusion Gadopiclenol at 0.05 mmol/kg yielded comparable change in contrast-to-noise ratio and morphologic characterization of brain tumors compared with gadobenate, gadoterate, or gadobutrol at 0.1 mmol/kg. Published under a CC BY 4.0 license. Online supplemental material is available for this article. See also the editorial by Tweedle in this issue.

Thoracic manifestations of primary humoral immunodeficiency: a comprehensive review

Humoral immunodeficiencies, which are characterized by defective production of antibodies, are the most common types of primary immunodeficiency. Pulmonary changes are present in as many as 60% of patients with humoral immunodeficiency. Chronic changes and recurrent infections in the respiratory airways are the main causes of morbidity and mortality in those affected by a humoral immunodeficiency. Medical imaging, especially computed tomography (CT), plays a crucial role in the initial detection and characterization of changes and in monitoring the response to therapy. The spectrum of abnormalities seen at thoracic imaging includes noninfectious airway disorders, infections, chronic lung diseases, chronic inflammatory conditions (granulomatosis, interstitial pneumonias), and benign and malignant neoplasms. Recognition of characteristic CT and radiographic features, and correlation of those features with clinical and laboratory findings, are necessary to differentiate between the many possible causes of parenchymal and mediastinal disease seen in patients with primary humoral immunodeficiencies.

Macrophage activity in infected areas of an experimental vertebral osteomyelitis model: USPIO-enhanced MR imaging--feasibility study

PURPOSE

To prospectively evaluate ultrasmall superparamagnetic iron oxide (USPIO) magnetic resonance (MR) imaging for the depiction of macrophages in infected areas of an experimental rabbit vertebral osteomyelitis model.

MATERIALS AND METHODS

Lumbar vertebral osteomyelitis was induced in 10 rabbits with intradiscal injection of bacteria in a vertebral disk (test level) versus saline injection in another disk (control level). After a mean interval of 12 days, rabbits were imaged prior to and 24 hours after administration of USPIO. The MR imaging protocol included T1-weighted spin-echo, T2-weighted fast spin-echo, and T2*-weighted gradient-echo sequences. MR findings were compared with histologic findings (macrophage immunostaining and Perls Prussian blue staining). A Wilcoxon signed rank test was used to compare signal-to-noise ratio (SNR) results before and after USPIO administration.

RESULTS

T1-weighted MR images of infected vertebral test levels obtained 24 hours after USPIO administration showed a significant increase in SNR (P = .005), whereas T2- and T2*-weighted images showed no significant changes in SNR (P = .14 and P = .87, respectively). Histologic examination results of infected areas demonstrated complete replacement of hematopoietic bone marrow by macrophage infiltration. Perls Prussian blue staining showed that some macrophages were iron loaded. T1- (P = .02), T2- (P = .04), and T2*-weighted (P = .04) images of control vertebrae showed a significant decrease in SNR. Histologic examination results confirmed the persistence of normal hematopoietic bone marrow without macrophage infiltration, which was reflected by more intensive Perls Prussian blue staining compared with that in infected areas.

CONCLUSION

MR imaging can depict USPIO-loaded macrophage infiltration present in infected areas in an experimental rabbit model of vertebral osteomyelitis.

Sacrotuberous ligament: relationship to normal, torn, and retracted hamstring tendons on MR images

PURPOSE

To evaluate continuity of the sacrotuberous ligament (STL) in normal and abnormal hamstring (HS) tendons on magnetic resonance (MR) images and to test the hypothesis that greater degrees of HS retraction are correlated with STL discontinuity.

MATERIALS AND METHODS

The institutional review board approved this retrospective HIPAA-compliant study and waived informed consent. Control cohort comprised 33 patients (mean age, 54.1 years) without HS abnormalities at hip MR arthrography. Study cohort comprised 100 patients (mean age, 55.3 years) with HS abnormalities at pelvic or hip MR imaging. Two musculoskeletal radiologists independently assessed STL continuity with the ischium and semimembranosus (SM) and conjoined biceps femoris and semitendinosus (BF-ST) tendons and evaluated these tendons for tendinopathy, partial tear, or rupture. A third musculoskeletal radiologist measured retraction of ruptured tendons. Inter- and intraobserver agreement was calculated with weighted κ or intraclass correlation coefficients. HS abnormalities in the cohorts were compared with Mann-Whitney test. In patients with tendon rupture, relationships between qualitative (STL and HS attachments) and quantitative (tendon retraction measurements) data were analyzed with analysis of variance and linear regression with Bonferroni correction.

RESULTS

STL was continuous with ischium in all patients. In control patients, STL was always continuous with BF-ST but never continuous with SM. In study patients, BF-ST tendon alone, SM tendon alone, and both BF-ST and SM tendons showed abnormalities in 17, six, and 77 patients, respectively. HS rupture occurred in 24 patients; it involved BF-ST tendon alone in 13 patients and both BF-ST and SM tendons in 11. STL was continuous with BF-ST tendon in 12 patients and discontinuous in 12 patients. Retraction of BF-ST tendon (mean, 33 mm; range, 5-81 mm) was independently correlated with STL continuity with BF-ST (P = .0001) and SM (P = .0004) tendon rupture. Retraction was significantly greater (P ≤ 0.01) when STL was discontinuous and SM tendon was ruptured. Inter- and intraobserver agreement was very good or excellent in categorization of HS abnormalities and measurement of retraction.

CONCLUSION

STL showed continuity with both ischium and BF-ST tendon but not SM tendon. In HS rupture, tendon retraction was significantly less when STL remained attached to BF-ST tendon.

An illustrative review to understand and manage metal-induced artifacts in musculoskeletal MRI: a primer and updates

This article reviews and explains the basic physical principles of metal-induced MRI artifacts, describes simple ways to reduce them, and presents specific reduction solutions. Artifacts include signal loss, pile-up artifacts, geometric distortion, and failure of fat suppression. Their nature and origins are reviewed and explained though schematic representations that ease the understanding. Then, optimization of simple acquisition parameters is detailed. Lastly, dedicated sequences and options specifically developed to reduce metal artifacts (VAT, SEMAC, and MAVRIC) are explained.

Survivor of a traumatic atlanto-occipital dislocation

Atlanto-occipital dislocation is a devastating ligamentous injury that most often turns fatal. However, because of on-site resuscitation improvements, the emergency teams are increasingly dealing with this condition. We report a rare case of atlanto-occipital dislocation (AOD) in a surviving patient with more than one-year follow-up. The mechanism of injury appears to be an extreme hyperextension applied to the head. This injury occurs more frequently in children since they are anatomically predisposed (flat articulation between the occiput and the atlas, increased ligamentous laxity). The diagnosis should be suggested by severe neurological injury after high trauma but also post-traumatic cardiorespiratory deficit. There have been reports of atlanto-occipital dilocations without neurologic impairment. A radiographic examination must be performed and lateral cervical radiographs should be acquired. However, additional imaging with CT or MRI may be required to aid diagnosis of AOD in cases in which radiographic findings are equivocal. Once the diagnosis of AOD has been confirmed, an anatomical classification should be made according to the magnitude of displacement. Fatal lesions are of neurological and vascular origin and some authors advocate the systematic use of angiography. Consensus regarding the management of AOD in adults has been achieved. Occipito-cervical arthrodesis is the recommended treatment option. We advocate a two-stage surgery: the patient is initially fitted with a halo vest then occipitocervical fusion is performed. Surgical treatment should be combined with cardiorespiratory management. The emergency teams should get familiar with this injury since they will be increasingly confronted to it. Early recognition and standard appropriate management is essential to avoid delayed treatment and complications.

Macrophage imaging by USPIO-enhanced MR for the differentiation of infectious osteomyelitis and aseptic vertebral inflammation

The purpose of this study was to prospectively evaluate USPIO-enhanced MR imaging for the differentiation of vertebral infectious osteomyelitis and sterile inflammation. Vertebral osteomyelitis and sterile vertebral inflammation were induced in two groups of six rabbits each. MRI examinations were performed including unenhanced and gadolinium-enhanced fat-saturated SE T1w sequences. Once endplate enhancement was observed on the T1 gadolinium-enhanced MR sequence, a second MRI examination (SE T1w sequence) was performed 24 h after USPIO administration (45 micromol Fe/kg). MR imaging was correlated with histopathological findings (macrophage immunostaining and Perls Prussian blue staining). On gadolinium-enhanced T1 sequences, a significant SNR increase in vertebral endplates was present in both groups without significant difference between the two groups (P = 0.26). On USPIO-enhanced T1 sequences, a significant SNR increase was only observed in the infection group (P = 0.03) with a significant difference in SNR between the infection and the sterile-inflammation groups (P = 0.002). Infected areas presented replacement of bone marrow by an intense macrophage infiltration, some being iron-loaded. Sterile inflammation showed a replacement of bone marrow by inflammatory tissue with only rare macrophages without any Perls blue staining. USPIO-enhanced MR imaging can distinguish infectious osteomyelitis from sterile vertebral inflammation due to different macrophage distributions in the two lesions.

Enchondromas in children: imaging appearance with pathological correlation

OBJECTIVE

Enchondromas are benign lesions that may present with nonspecific features on imaging in children. Correlation of histology with imaging findings is often required to make the final diagnosis of a benign lesion. The aim of this study was to review imaging and pathological findings of enchondromas in children.

MATERIALS AND METHODS

Imaging examinations of 12 enchondromas in 11 patients (median age 14 years) were retrospectively reviewed. Imaging evaluation included an assessment of lesion size, relationship to the growth plate, mineralization, matrix and periosteal reaction, intrinsic MR signal characteristics, and intraosseous and soft-tissue edema. Pathological findings were reviewed.

RESULTS

Lesions were located in the phalanx in 33% (4 out of 12), metacarpal in 25% (3 out of 12), femur in 33% (4 out of 12) and tibia in 8% cases (1 out of 12). The mean size was 28 mm (range, 11-70 mm). Matrix mineralization in a typical "rings-and-arcs" pattern was observed in 20% of the lesions with available radiographs/CT (2 out of 10). Lesions were expansive with endosteal scalloping in 75% of cases (9 out 12) and contacted the growth plate in 50% of cases (6 out of 12). All enchondromas in which MR imaging was available (5 out of 5) demonstrated typical cartilaginous matrix of lobules of high T2 signal, low T1 signal, and peripheral enhancement.

CONCLUSION

Enchondromas in children are relatively large lesions, with frequent endosteal scalloping and rare matrix mineralization.

Interdisciplinary consensus statements on imaging of scapholunate joint instability

Objectives

The purpose of this agreement was to establish evidence-based consensus statements on imaging of scapholunate joint (SLJ) instability by an expert group using the Delphi technique.

Methods

Nineteen hand surgeons developed a preliminary list of questions on SLJ instability. Radiologists created statements based on the literature and the authors’ clinical experience. Questions and statements were revised during three iterative Delphi rounds. Delphi panellists consisted of twenty-seven musculoskeletal radiologists. The panellists scored their degree of agreement to each statement on an eleven-item numeric scale. Scores of ‘0’, ‘5’ and ‘10’ reflected complete disagreement, indeterminate agreement and complete agreement, respectively. Group consensus was defined as a score of ‘8’ or higher for 80% or more of the panellists.

Results

Ten of fifteen statements achieved group consensus in the second Delphi round. The remaining five statements achieved group consensus in the third Delphi round. It was agreed that dorsopalmar and lateral radiographs should be acquired as routine imaging work-up in patients with suspected SLJ instability. Radiographic stress views and dynamic fluoroscopy allow accurate diagnosis of dynamic SLJ instability. MR arthrography and CT arthrography are accurate for detecting scapholunate interosseous ligament tears and articular cartilage defects. Ultrasonography and MRI can delineate most extrinsic carpal ligaments, although validated scientific evidence on accurate differentiation between partially or completely torn or incompetent ligaments is not available.

Conclusions

Delphi-based agreements suggest that standardized radiographs, radiographic stress views, dynamic fluoroscopy, MR arthrography and CT arthrography are the most useful and accurate imaging techniques for the work-up of SLJ instability.

Key Points

• Dorsopalmar and lateral wrist radiographs remain the basic imaging modality for routine imaging work-up in patients with suspected scapholunate joint instability.

• Radiographic stress views and dynamic fluoroscopy of the wrist allow accurate diagnosis of dynamic scapholunate joint instability.

• Wrist MR arthrography and CT arthrography are accurate for determination of scapholunate interosseous ligament tears and cartilage defects.

Reduced DICER1 Expression Bestows Rheumatoid Arthritis Synoviocytes Proinflammatory Properties and Resistance to Apoptotic Stimuli

OBJECTIVE

While the regulatory role of individual microRNAs (miRNAs) in rheumatoid arthritis (RA) is well established, the role of DICER1 in the pathogenesis of the disease has not yet been investigated. The purpose of this study was to analyze the expression of factors involved in miRNA biogenesis in fibroblast-like synoviocytes (FLS) from RA patients and to monitor the arthritis triggered by K/BxN serum transfer in mice deficient in the Dicer gene (Dicer(d/d) ).

METHODS

The expression of genes and precursor miRNAs was quantified by quantitative reverse transcription-polymerase chain reaction (qRT-PCR). MicroRNA macroarray profiling was monitored by qRT-PCR. Cytokines were quantified by enzyme-linked immunosorbent assay. Experimental arthritis in mice was achieved by the transfer of serum from K/BxN donors. Apoptosis was quantified using an enzyme-linked immunosorbent assay.

RESULTS

We found decreased DICER1 and mature miRNA expression in synovial fibroblasts from RA patients. These cells were hyperresponsive to lipopolysaccharide, as evidenced by their increased interleukin-6 secretion upon stimulation. Experimental serum-transfer arthritis in Dicer(d/d) mice confirmed that an unbalanced biogenesis of miRNAs correlated with an enhanced inflammatory response. Synoviocytes from both RA patients and Dicer(d/d) mice exhibited increased resistance to apoptotic stimuli.

CONCLUSION

The findings of this study further substantiate the important role of DICER1 in the maintenance of homeostasis and the regulation of inflammatory responses.

Vascular complication after percutaneous femoral cerclage wire

Cerclage wire is an effective fracture fixation method. However, its mechanical benefits are countered by local ischemia. Its efficacy for treating femoral periprosthetic fractures has been demonstrated since femoral fixation is possible even there is a stem in the diaphysis. It securely holds the proximal femur typically with an additional plate. The development of minimally-invasive surgery with plate fixation has led to the cerclage wire being inserted percutaneously. Here, we report on a case of secondary femoral ischemia following percutaneous cerclage wire of a periprosthetic femoral fracture. This was a Vancouver type B1 fracture. On the 3rd day after admission, minimally-invasive fixation with a femoral locking plate was performed with five cerclage wires added percutaneously. During the immediate postoperative course, the patient developed ischemia of the operated leg that required vascular surgery after confirmation by CT angiography. An arterial stop was visible with deviation of the superior femoral artery, which was not properly surrounded by the cerclage wire. The latter pulled perivascular tissues towards the femur. When combined with reduced arterial elasticity due to severe atherosclerosis, it resulted in arterial plication. The postoperative course was marked by multiple organ failure and death of the patient. Percutaneous surgery is an attractive option but has risks. The presence of severe atherosclerosis is a warning sign for loss of tissue elasticity. This complication can be prevented by preparing the bone surfaces and carefully positioning the patient on the traction table to avoid forced adduction. The surgeon must also be familiar with alternative techniques to cerclage wire such as polyaxial screws and additional plates.

Diffusion-weighted MRI, dynamic susceptibility contrast MRI and ultrasound perfusion quantification of denervated muscle in rabbits

OBJECTIVE

The purpose of this study was to assess denervated muscle perfusion using dynamic susceptibility contrast MRI (DSCMRI) and contrast-enhanced ultrasound (CEUS), and to measure denervated muscle apparent diffusion coefficient (ADC) on b1000 diffusion-weighted MRI (DWMRI) at 3 T in order to clarify whether muscle denervation leads to an increase in the extracellular extravascular space, or an increase in blood flow-or both.

MATERIALS AND METHODS

Axotomy of the right sciatic nerve of six white rabbits was performed at day 0. At day 9, hind limb muscles MRI and CEUS were performed to assess the consequences of denervation and both semimembranosus muscles of each rabbit were explanted for histological studies. Signal intensity on T2- and T1-weighted MRI, ADC on DWMRI, maximum signal drop (MSD) on DSCMRI and the area under the curve (AUC) on CEUS were measured over circular regions of interest (ROI), in both semimembranosus muscles. Non-parametric Wilcoxon matched-pairs tests were used to assess the mean differences between denervated and normal muscles.

RESULTS

T2 fat-saturated (FS) MRI studies showed a strong signal in the right semimembranosus muscles compared with the left side, and gadolinium enhancement was observed on T1 FS MRI. Denervated muscles show a significant increase in ADC on DWMRI (p < 0.01) and a significant signal enhancement on DSCMR imaging (p < 0.05) and on first-pass CEUS (p < 0.05).

CONCLUSION

The results of this study--based on perfusion- and diffusion-weighted images--suggest that, after denervation, both increased blood flow through muscle tissue and expansion of the extracellular water volume are present.

Satisfactory long-term MRI after autologous chondrocyte implantation at the knee

PURPOSE

Autologous chondrocyte implantation (ACI) to address isolated condylar lesions is supposed to limit degenerative deterioration in neutrally aligned knees. Here, we report long-term results of the first-generation ACI technique with periosteal flap.

METHODS

Twelve patients, 29 years old on average, were included on the basis of pre-operative MRI selection of lesions >2 cm2. Cartilage carrots were harvested arthroscopically, then cultured and finally re-implanted within a mean time interval of 12 weeks. Ten-year MRI results were analysed according to a semi-quantitative scale, along with functional assessment based on International Knee Documentation Committee score, Lysholm et al. score and the Tegner et al. activity scale.

RESULTS

One patient secondarily required valgus tibial osteotomy with mosaic plasty. Another incurred graft hypertrophy that necessitated arthroscopic peeling. MRI showed that cartilage repair filled more than 50% of the initial defect in 9 patients. Standard radiographs revealed slight narrowing of the joint line. Overall, functional scores improved durably by 50%, although activity level decreased substantially.

CONCLUSION

ACI contained degenerative changes within moderate stages while maintaining durable functional improvement. However, in the absence of controls, it was difficult to differentiate between these findings and the spontaneous evolution of non-treated lesions.

LEVEL OF EVIDENCE

Case series, Level IV.