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

Magnetic resonance imaging-guided spine injections

Magnetic resonance (MR)-guided spine injections describe techniques for selective spine injection procedures, in which MR imaging is used to visualize spinal targets and needle placement, monitor the injected drugs, and detect spread to potentially confounding nearby structures. The introduction of clinical high-field wide-bore MR imaging systems has increased the practicability and availability of MR-guided spine injections. The use of 1.5-T field strength, modern coils, and parallel imaging technology increases the MR signal, which can be utilized for faster temporal image acquisition, higher image resolution, better image contrast, or combinations thereof. Magnetic resonance imaging guidance provides excellent osseous and soft-tissue detail of spinal structures and is well suited to avoid radiation exposure. In this article, we discuss the technical background of interventional MR imaging, review the literature, and illustrate interventional MR imaging techniques of commonly performed spinal injection procedures, including sacroiliac joint injections, lumbar facet joint injections, selective spinal nerve root infiltration, and percutaneous drug delivery to the lumbar sympathetic nerves.

MRI image overlay: Application to arthrography needle insertion

Magnetic Resonance Imaging (MRI) offers great potential for planning, guiding, monitoring and controlling interventions. MR arthrography (MRAr) is the imaging gold standard for assessing small ligament and fibrocartilage injury in joints. In contemporary practice, MRAr consists of two consecutive sessions: (1) an interventional session where a needle is driven to the joint space and MR contrast is injected under fluoroscopy or CT guidance; and (2) a diagnostic MRI imaging session to visualize the distribution of contrast inside the joint space and evaluate the condition of the joint. Our approach to MRAr is to eliminate the separate radiologically guided needle insertion and contrast injection procedure by performing those tasks on conventional high-field closed MRI scanners. We propose a 2D augmented reality image overlay device to guide needle insertion procedures. This approach makes diagnostic high-field magnets available for interventions without a complex and expensive engineering entourage. In preclinical trials, needle insertions have been performed in the joints of porcine and human cadavers using MR image overlay guidance; in all cases, insertions successfully reached the joint space on the first attempt.

MRI-guided interventions of the musculoskeletal system

MRI has become the modality of choice for many diagnostic questions in musculoskeletal radiology. Naturally, with the increasing role of MRI in diagnosis of musculoskeletal conditions, clinicians have been eager to explore the possibility of using MR guidance for musculoskeletal procedures. Researchers are actively investigating the utility and practicality of MRI compared with more established modalities for procedure guidance such as computed tomography, fluoroscopy, and ultrasound. Early studies have demonstrated the safety and feasibility of MR guidance for biopsies, spine procedures, cyst aspirations, therapeutic injections, and tumor ablation. Applications in the musculoskeletal system are likely to expand as technology improves and clinicians gain more experience. Hybrid X-ray fluoroscopy/MR imaging systems hold great promise for the future of musculoskeletal intervention by combining the excellent temporal and spatial resolution of X-ray with the anatomic detail provided by MRI.

Transverse morphology of the sacroiliac joint: effect of angulation and implications for fluoroscopically guided sacroiliac joint injection

OBJECTIVE

Effects of angulation of computed tomography (CT) reconstruction plane on sacroiliac (SI) joint morphology were studied, and factors influencing the approach to fluoroscopically guided SI joint injection were assessed.

DESIGN AND PATIENTS

CT scans of pelvises were reformatted on 41 subjects, aged 51.7 (+/-15.1) years. Transverse images were reconstructed at the caudal 3 cm of the SI joint tilting plane of reconstruction from -30 degrees to +30 degrees at 15 degrees increments. Anteroposterior diameter of joint (depth), angle from sagittal plane (orientation angle), and distance from skin were measured. Joint contour was classified, and presence of bone blocking access to the joint was recorded. Comparison between angles were analysed by t-test. Relationships between variables were assessed by a Pearson correlation test.

RESULTS

Depth was shorter with angulation in the inferior direction (P<0.01). Orientation angle increased with superior angulation (P<0.01). Distance from skin increased (P<0.01) with angulation in either direction. Joint contour was significantly different from baseline at each angle (P<0.001) but highly variable. Inferior angulation resulted in interposition of ilium between skin and SI joint, and superior angulation caused bone block due to the lower sacrum. None of these features was identified without tilting of the reconstruction plane, and effects were more pronounced with steeper angulation.

CONCLUSION

Angulation of the reconstruction plane considerably affects the appearance of the sacroiliac joints. By shortening joint depth, an inferiorly directed approach to SI joint injection may make fluoroscopic guidance easier, although associated bony interposition can prevent access to the synovial compartment. A superiorly directed approach is more likely to have adverse effects.

Interventional and intraoperative MRI at low field scanner--a review

Magnetic resonance imaging (MRI) is a cutting edge imaging modality in detecting diseases and pathologic tissue. The superior soft tissue contrast in MRI allows better definition of the pathology. MRI is increasingly used for guiding, monitoring and controlling percutaneous procedures and surgery. The rapid development of interventional techniques in radiology has led to integration of imaging with computers, new therapy devices and operating room like conditions. This has projected as faster and more accurate imaging and hence more demanding procedures have been applied to the repertoire of the interventional radiologist. In combining features of various other imaging modalities and adding some more into them, interventional MRI (IMRI) has potential to take further the interventional radiology techniques, minimally invasive therapies and surgery. The term "Interventional MRI" consists in short all those procedures, which are performed under MRI guidance. These procedures can be either percutaneous or open surgical of nature. One of the limiting factors in implementing MRI as guidance modality for interventional procedures has been the fact, that most widely used magnet design, a cylindrical magnet, is not ideal for guiding procedures as it does not allow direct access to the patient. Open, low field scanners usually operating around 0.2 T, offer this feature. Clumsy hardware, bad patient access, slow image update frequency and strong magnetic fields have been other limiting factors for interventional MRI. However, the advantages of MRI as an imaging modality have been so obvious that considerable development has taken place in the 20-year history of MRI. The image quality has become better, ever faster software, new innovative sequences, better MRI hardware and increased computing power have accelerated imaging speed and image quality to a totally new level. Perhaps the most important feature in the recent development has been the introduction of open configuration low field MRI devices in the early 1990s; this enabled direct patient access and utilization of the MRI as an interventional device. This article reviews the current status of interventional and intraoperative MRI with special emphasis in low field surrounding.

Sacroiliac Joint Pain: A Comprehensive Review of Anatomy, Diagnosis, and Treatment

Sacroiliac (SI) joint pain is a challenging condition affecting 15% to 25% of patients with axial low back pain, for which there is no standard long-term treatment. Recent studies have demonstrated that historical and physical examination findings and radiological imaging are insufficient to diagnose SI joint pain. The most commonly used method to diagnose the SI joint as a pain generator is with small-volume local anesthetic blocks, although the validity of this practice remains unproven. In the present review I provide a comprehensive review of the anatomy, function, and mechanisms of injury of the SI joint, along with a systematic assessment of its diagnosis and treatment.

Sacroiliac joint dysfunction: evaluation and management

Sacroiliac joint dysfunction is believed to be a significant source of low back and posterior pelvic pain.

METHODS

To assess the clinical presentation, diagnostic testing, and treatment options for sacroiliac joint dysfunction, a systematic literature review was performed using MEDLINE.

RESULTS

Presently, there are no widely accepted guidelines in the literature for the diagnosis and treatment of sacroiliac instability. Establishing management guidelines for this disorder has been complicated by the large spectrum of different etiologic factors, the variability of patient history and clinical symptoms, limited availability of objective testing, and incomplete understanding of the biomechanics of the sacroiliac joint.

CONCLUSIONS

A reliable examination technique to identify the sacroiliac joint as a source of low back pain seems to be pain relief following a radiologically guided injection of a local anaesthetic into the sacroiliac joint. Most patients respond to non-operative treatment. Patients who do not respond to non-operative treatment should be considered for operative sacroiliac joint stabilization.

High- Versus Low-Field MR Imaging

The role of MR imaging as a noninvasive technique in the detection and evaluation of musculoskeletal diseases is unquestionable. Most of the studies reported in the literature are based on high-field MR imaging. Initial studies performed with low-field-strength have reported unsatisfactory results in the assessment of the musculoskeletal system. Recent improvements, however, have generated a renewed interest in low-field-strength MR imaging. This article presents the principal applications and results published in the literature.

Pediatric MR-guided interventions

MRI guided interventions are a relatively new but steadily growing field within surgery in pediatric age. Besides the advantages of MRI, such as multiplanar capability and excellent soft tissue contrast and spatial resolution, particularly relevant for the pediatric population is the lack of ionizing radiation. There is meanwhile a group of well defined diagnostic or therapeutic indications for applying MR imaging during pediatric interventions. Aim of this review is to give an overview about indications of MR-guided procedures in children as well as the advantages and disadvantages of MR-guided interventions. We also briefly discuss interventional MR-systems and MR-compatible devices. It is our opinion that MR-guidance for pediatric interventions is a promising technique at the beginning of its development.

New developments in imaging for diagnosis and therapy monitoring in rheumatic diseases

The availability of therapeutic modalities that are able to stop inflammatory joint damage has also markedly influenced recent developments in muskuloskeletal imaging. One focus of interest is the detection of joint pathology as early as possible in order to prevent erosive bony changes. Ultrasonography and magnetic resonance imaging are the most valuable technologies in this respect. Another focus is on the exact assessment and documentation of joint damage using scoring systems not only in therapeutic trials, but also in clinical practice. In addition to these recent advances in peripheral and axial joint imaging, this chapter also discusses advances in vascular imaging and scintigraphy in rheumatoid diseases as well as interventional procedures guided by imaging technologies.

Interventional radiology and the musculoskeletal system

Imaging-guided interventional procedures are becoming increasingly important in clinical rheumatology, since arthrocentesis of peripheral joints and the spine, as well as soft tissue injections, have a high rate of para-articular localisation when performed as blind techniques. Ultrasound-guided needle placement is the method of choice for interventional procedures on peripheral joints and for soft tissue injections. Fluoroscopy and computed tomography (CT) are not recommended for these indications due to the application of ionising radiation and the high procedural effort. By contrast, CT and magnetic resonance imaging are preferred for a variety of percutaneous procedures on the spine and sacroiliac joints. The increasing use of these methods for interventional purposes should improve both technical and procedural quality, thus ensuring cost-effectiveness and patient safety.

Interventional and intraoperative MR: review and update of techniques and clinical experience

The concept of interventional magnetic resonance imaging (MRI) is based on the integration of diagnostic and therapeutic procedures, favored by the combination of the excellent morphological and functional imaging characteristics of MRI. The spectrum of MRI-assisted interventions ranges from biopsies and intraoperative guidance to thermal ablation modalities and vascular interventions. The most relevant recently published experimental and clinical results are discussed. In the future, interventional MRI is expected to play an important role in interventional radiology, minimal invasive therapy and guidance of surgical procedures. However, the associated high costs require a careful evaluation of its potentials in order to ensure cost-effective medical care.

Sacroiliac joint injections performed with sonographic guidance

OBJECTIVE

To investigate the feasibility and effectiveness of sonographic guidance for therapeutic intra-articular sacroiliac joint injections in patients with sacroiliitis.

METHODS

Thirty-four consecutive patients with sacroiliitis were enrolled in this study. The synovial portions of 60 sacroiliac joints received injections under sonographic guidance. For treatment, a mixture of a corticosteroid and a local anesthetic was injected intra-articularly. Fluoroscopic spot images were obtained to assess the accuracy of the sonographically guided technique.

RESULTS

Of the 60 sonographically guided injections, 46 (76.7%) were successful (i.e., intra-articular), and 14 (23.3%) were missed. The successful intra-articular injection rate was 60% in the first 30 injections, and it gradually improved, reaching 93.5% in the last 30 injections. The mean procedure time was 9 minutes.

CONCLUSIONS

Our initial experience suggests that sonographically guided therapeutic injections to sacroiliac joints could be valuable alternatives to other guidance modalities in patients with sacroiliitis. In the hands of experienced radiologists, this technique is safe, rapid, and reproducible.

Percutaneous MR-guided discography in a low-field system using optical instrument tracking: a feasibility study

PURPOSE

To evaluate the feasibility of MRI-guided discography with optical tracking.

MATERIAL AND METHODS

12 consecutive patients who had a clinical suspicion of lumbar discogenic pain and/or suggestive finding of disc degeneration in imaging studies (MRI, CT, plain radiography) underwent MRI-guided discography in order to determine possible pain provocation during puncture and contrast injection. An 0.23 T open configuration MRI device with interventional tools (Outlook Proview, Philips Medical Systems, MR Technologies, Finland) was used in procedural imaging and instrument guidance. An optical guidance tool was attached to the MRI compatible needle (Chiba-type MReye, Cook, Bloomington, IN). After initial disc puncture, 1-2 mL of gadolinium contrast (Magnevist, 469 mg/mL, Schering AG, Germany) saline mixture (1:8) was injected into the disc. Immediately after injection, sagittal FE T1 weighted images were obtained to verify the final position of the needle and formation of the MRI discogram. On nine patients, additional noncontrast sagittal fast spin echo (FSE) T1, FSE T2, and axial 3D T1 gradient echo imaging was performed before and after contrast media injection to obtain MRI discograms.

RESULTS

Overall, 35 disc punctures were initialized and 34 MRI discograms were obtained. In all punctures, a positive or negative pain response was obtained. The average time for performing a procedure for three discs was 1 hour 25 minutes (minimum 45 minutes, maximum 2 hours, 15 minutes), and the average number of imaging sequences used for a puncturing one disc was 12. On one disc, the puncture failed and a discogram was not acquired. There was one complication (disc collapse) reported during follow-up.

CONCLUSION

Our results show that MRI guidance in performing discography is accurate and relatively safe. It is a technically comparable method to CT-guidance or fluoroscopy.