Inaccuracies in the Use of Magnification Markers in Digital Hip Radiographs

BACKGROUND

With the ubiquity of digital radiographs, the use of digital templating for arthroplasty has become commonplace. Although improved accuracy with digital radiographs and magnification markers is assumed, it has not been shown.

QUESTIONS/PURPOSES

We wanted to (1) evaluate the accuracy of magnification markers in estimating the magnification of the true hip and (2) determine if the use of magnification markers improves on older techniques of assuming a magnification of 20% for all patients.

METHODS

Between April 2013 and September 2013 we collected 100 AP pelvis radiographs of patients who had a THA prosthesis in situ and a magnification marker placed per the manufacturer's instructions. Radiographs seen during our standard radiographic review process, which met our inclusion criteria (AP pelvic view that included a well-positioned and observed magnification marker, and a prior total hip replacement with a known femoral head size), were included in the analysis. We then used OrthoView(TM) software program to calculate magnification of the radiograph using the magnification marker (measured magnification) and the femoral head of known size (true magnification).

RESULTS

The mean true magnification using the femoral head was 21% (SD, 2%). The mean magnification using the marker was 15% (SD, 5%). The 95% CI for the mean difference between the two measurements was 6% to 7% (p < 0.001). The use of a magnification marker to estimate magnification at the level of the hip using standard radiographic techniques was shown in this study to routinely underestimate the magnification of the radiograph using an arthroplasty femoral head of known diameter as the reference. If we assume a magnification of 20%, this more closely approximated the true magnification routinely. With this assumption, we were within 2% magnification in 64 of the 100 hips and off by 4% or more in only four hips. In contrast, using the magnification marker we were within 2% of true magnification in only 20 hips and were off by 4% or more in 59 hips.

CONCLUSION

We found the use of a magnification marker with digital radiographs for preoperative templating to be generally inaccurate, with a mean error of 6% and range from -5% to 15%. Additionally, these data suggest that the use of a magnification marker while taking preoperative radiographs of the hip may be unnecessary, as simply setting the software to assume a 20% magnification actually was more accurate.

LEVEL OF EVIDENCE

Level III, diagnostic study.

Shoulder-Mounted Robot for MRI-guided arthrography: Accuracy and mounting study

A new version of our compact and lightweight patient-mounted MRI-compatible 4 degree-of-freedom (DOF) robot for MRI-guided arthrography procedures is introduced. This robot could convert the traditional two-stage arthrography procedure (fluoroscopy-guided needle insertion followed by a diagnostic MRI scan) to a one-stage procedure, all in the MRI suite. The results of a recent accuracy study are reported. A new mounting technique is proposed and the mounting stability is investigated using optical and electromagnetic tracking on an anthropomorphic phantom. Five volunteer subjects including 2 radiologists were asked to conduct needle insertion in 4 different random positions and orientations within the robot's workspace and the displacement of the base of the robot was investigated during robot motion and needle insertion. Experimental results show that the proposed mounting method is stable and promising for clinical application.

Diffraction-Enhanced Computed Tomographic Imaging of Growing Piglet Joints by Using a Synchrotron Light Source

The objective of this project was to develop and test a new technology for imaging growing joints by means of diffraction-enhanced imaging (DEI) combined with CT and using a synchrotron radiation source. DEI-CT images of an explanted 4-wk-old piglet stifle joint were acquired by using a 40-keV beam. The series of scanned slices was later 'stitched' together, forming a 3D dataset. High-resolution DEI-CT images demonstrated fine detail within all joint structures and tissues. Striking detail of vasculature traversing between bone and cartilage, a characteristic of growing but not mature joints, was demonstrated. This report documents for the first time that DEI combined with CT and a synchrotron radiation source can generate more detailed images of intact, growing joints than can currently available conventional imaging modalities.

Shielding during x-ray examination of pediatric female patients with developmental dysplasia of the hip

Patients with developmental dysplasia of the hip (DDH) generally undergo multiple x-ray examinations of both hip joints. During these examinations, the gonads are completely exposed to radiation, unless shielded. Although many types and sizes of gonad shields exist, they often do not provide adequate protection because of size and placement issues; additionally, these shields are frequently omitted for female patients. Our aim was to assess gonad protection during x-ray examination that is provided by gonad shields designed for individual female patients with DDH.We retrospectively retrieved data from the Picture Archiving and Communication System database; pelvic plain x-ray films from 766 females, 18 years old or younger, were included in our analysis. Based on x-ray measurements of the anterior superior iliac spine, we developed a system of gonad shield design that depended on the distance between anterior superior iliac spine markers. We custom-made shields and then examined shielding rates and shielding accuracy before and after these new shields became available. Standard (general-purpose) shields were used before our custom design project was implemented. The shielding rate and shielding accuracy were, respectively, 14.5% and 8.4% before the project was implemented and 72.7% and 32.2% after it was implemented. A shield that is more anatomically correct and available in several different sizes may increase the likelihood of gonad protection during pelvic x-ray examinations.

[Proposal for an auxiliary tool designed to reduce retake rates for lateral radiography of the knee joint]

The reproducibility of lateral radiography of the knee joint in the lateral position is low because patient positioning can be easily affected by passive rotation of the knee joint. We calculated the correction angle of the femoral external rotation and the lower leg elevation and developed our own auxiliary tool for obtaining a lateral view image. We were able to obtain, in a single attempt, an image with misalignment of the condyle limited to less than 7 mm. Our tool also contributed to the reduction of the re-imaging rate, suggesting its usefulness in contributing to a lower re-imaging rate for lateral radiography of the knee joint.

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.

Registration of low dose bi-planar acquisitions for motion analysis

In this paper, we introduce a 2d-3d registration method for searching the motion of knee bones. We use a low dose bi-planar acquisition system that provides us with simultaneous frontal and profile radiographs in different positions, and the 3d volume reconstruction of the standing position. The purpose here is to reduce the user intervention during the motion tracking. The registration method is based on the central slice Fourier Transform theorem. Motion results with rotations and translations using synthetic data are shown.

Radiofrequency cannula with active tip radio-opaque marker: image analysis for facet, gray ramus, and dorsal root ganglion techniques

BACKGROUND

Radiofrequency neurolysis is a common technique used in the treatment of chronic pain, particularly facet (zygapophyseal joint) arthralgia. A needle-like cannula is insulated except for the exposed active tip, which is positioned as parallel and adjacent as possible to the targeted nerve branch. Via an inserted probe connected to a radiofrequency generator, energy flowing from the tip of the cannula creates a heat lesion in the 80 - 85 degree Celsius range mostly about the length of the exposed active tip and in proportion to the diameter of the probe. The common active tip lengths used for neurolysis are 5mm or 10mm. The cannulae are FDA approved. The manufacturer advises physicians not to bend or otherwise modify a cannula prior to use. The cannulae are available straight or bent, sharp and blunt. The technique is guided under C-arm fluoroscopy. X-rays passing through the patient demonstrate in 2 dimensions the projected relative radio-opaque bony landmarks and the metallic cannula. Most currently available cannulae are uniform in their radio-opacity from tip to hub. The physician must make an educated guess as to the portion of the cannula that will be making the lesion in relationship to the bony landmark.

OBJECTIVE

A new radiofrequency cannula with a radio-opaque marker (ROC) delineates the proximal end of the active tip. The cannula was used in a phantom model. Images were reproduced with explanation of the potential advantage of the new device.

RESULT

The marker on the new cannula was visible and did help delineate the active tip as well as its orientation. It was also helpful in making sequential lesions at the same nerve using a "tip to tail" repositioning technique.

CONCLUSION

The ROC did represent an improvement over standard cannulae to optimize visualization of cannula and thus lesion placement using a phantom model. The applications described were only for conventional or "hot" RF.

The clinical utility of computed tomography compared to conventional radiography in diagnosing sacroiliitis. A retrospective study on 910 patients and literature review

OBJECTIVE

Ankylosing spondylitis (AS) is a progressive, debilitating disease with complex symptoms, unclear etiology and pathogenesis, and difficult diagnosis. Current imaging methods are useful in diagnosing AS and other spondyloarthropathies, and are frequently used in investigations of sacroiliitis. The radiographic diagnosis of sacroiliitis has large interobserver variations. Computed tomography (CT) has been used for evaluation of sacroiliitis since 1979, and has been evaluated in several studies, most of them with a limited number of patients. These studies have shown a large number of false-negative results from radiography.

METHODS

In a retrospective study of clinical data, we evaluated 910 patients with AS who were examined by radiography and CT within a 2-year period. The reported outcomes from radiography and CT were compared.

RESULTS

The agreement between radiography and CT data was only fair, with a kappa value of 0.2418. There were 35.0% false-positive radiography reports, 22.5% false-negative radiography reports, and 86.0% false-equivocal radiography reports. In total, 41.3% of all radiological reports gave a false answer. While the number of false negatives was similar to that previously reported, the number of false positives was much higher than previously reported, and is probably similar to everyday radiology reporting.

CONCLUSION

Our results indicate that the clinical utility of radiography for evaluation of sacroiliitis is limited. The high rate of inaccurate results should motivate the use of sectional imaging for its superior performance.

Vibroarthrography--a possible functional non-invasive method for early detection damaged cartilage joint

The vibroacoustic signals emitted by the diarthrodial articulation during a normal movement differentiates a healthy case from a pathologic one, due to alteration in forms and contact surfaces. The differences are shown by a various dynamics of the vibroacoustic spectra. Parametric representation of the acquired signals, filtering and clinical interpretation of those allow classification and fast recognition of a normal/pathologic status of the investigated articulation by the physician. Our method of acquiring the sound and vibration signals is effectuated completely non-invasive, with a set of translators using Pulse - sounds and vibrations analyzers (a matrix of prepolarised microphones with measurement domain in infrasound scale and piezoelectric acceleration transducers). A comparative study of vibroacoustic and thermal spectra, with early alterations revealed by knee nuclear magnetic resonance, correlates vibroacoustic and thermic spectra alterations with morphological ones, by determining certain limits between normal and pathological morphofunctional patterns. This prospective comparative study will help us evaluate the method in terms of sensibility, specificity, negative and positive predictive value, indices that assure the diagnostic power to the method.

Differential diagnosis of rheumatic diseases using conventional radiography

The approach to the differential diagnosis of rheumatic diseases using conventional radiography is systematic and module-oriented, which, with respect to future developments, forms the basis for computer-assisted diagnosis (CAD). The indications follow consensus-based referral criteria and attempts should be made to raise the evidence level of the recommendations. Investigation techniques have been improved in the last few years with the use of digital radiography. New imaging technologies may be available in the future that will achieve at least the same quality of images, while exposing patients to a significantly lower radiation dose. The interpretation of radiographical signs could be enhanced through a correlation with other imaging modalities. Computer-assisted techniques with image processing tools for automated measurements, lesion detection and in the form of expert systems are under development. With conventional radiography embedded in CAD systems, promising options will be available to enhance the differential diagnosis of rheumatic diseases.

[The advanced technology of three-dimensional medical imaging in spine, bone and joints]

The advanced technology of three-dimensional (3-D) medical imaging allows us to understand the patient specific anatomy in detail. Especially, in orthopedic surgery, treated spinal diseases or the disorders of bone and joints, the 3-D computed tomography(CT), such as multi-slice CT and helical CT is a useful tool for clinical diagnosis and surgical treatment. Since 1995, by the use of these 3-D CT image data, computer navigation system and surgical robot were developed and applied to a spinal instrumentation surgery and an artificial joint replacement. Now surgeons can perform the precise and safe surgical procedure by the computer guidance on the base of 3-D medical imaging.

Radiography of rabbit articular cartilage with diffraction-enhanced imaging

Articular cartilage of synovial joints is not visible with conventional X-ray imaging. Hence, the gradual degeneration and destruction of articular cartilage, which is characteristic of degenerative joint diseases, is only detected at a late stage when the cartilage is lost and the joint space that it once occupied narrows. The development of an X-ray imaging technique that could detect both the degenerative cartilage and bone features of joint diseases is of special interest. Here we show, for the first time, that a high-contrast imaging technique, diffraction-enhanced X-ray imaging (DEI), allows the visualization of articular cartilage of both disarticulated and articulated rabbit knee joints. Furthermore, a single cartilage lesion can be visualized within an intact joint. The results suggest that DEI has the potential to be of use in the study of cartilage degeneration.

Description of the potential of an arthrometer for standard and reduced radiographs suitable to measurement of angles and segments of hip, knee, foot and joint space widths

BACKGROUND

Primary osteoarthritis is usually selected in either epidemiological or therapeutic studies. This implies exclusions. Among cases of secondary osteoarthritis considered for either stratification or exclusion--or for prognosis and treatment in daily practice--are those due to architectural defects. Parameters of the latter should be measured to ascertain diagnosis. At present, measurements have to be performed either on digitized reduced films or standard radiographs.

OBJECTIVE

To finalize an instrument capable of measuring the main angles and segments characteristic of the main dysmorphisms of the hip, knee and foot on different sizes of films.

METHODS

An arthrometer drawn on transparent material to be placed on radiographs was designed, involving several appropriate protractors and millimetric scales; it was tested on 60 hip, 35 knee and 17 foot radiographs with various architectural defects. Angles and segments most often used according to literature were measured. Reduction rates of films were various, reflecting the range of radiograph sizes currently used in everyday practice.

RESULTS

Measurements were easily performed on radiographs from standard (100%) up to 50% of reduction rate. So the arthrometer allows the recognition, especially in moderate, not obvious forms, of the following developmental or acquired dysmorphisms: hip congenital dysplasia and subluxation, including coxa valga and neck excess of anteversion; acetabular protrusion and coxa vara; tilt deformity; knee: patellar height abnormalities, patellar maltracking, trochlear depth insufficiency; foot: pes cavus, flatfoot. Angle and segment ratios do not change in reduced film, whereas segments (absolute lengths) obviously should be converted according to the reduction rate for retrieving the classical values established for decades.

CONCLUSION

The arthrometer allows us to measure the relevant parameters of various dysmorphisms without drawing lines over the films themselves. It is suitable to reduced as well to standard radiographs. However, only the instrument and its ability to be used in various films sizes are here presented. Study of reproducibility of measurements--especially concerning the joint space width--remain to be performed.

[Introduction of a new mobile C-arm/CT combination equipment (ISO-C-3D). Initial results of 3-D sectional imaging]

Preclinical evaluation of a new mobile C-arm image amplifier with an option for three-dimensional computed tomography (CT) imaging (prototype Iso-C3D) with respect to high-contrast resolution and possible clinical applications. Cadaveric specimens (n = 30) of different joints of the lower and upper extremities and specimens of the spinal column were examined with the Iso-C3D and evaluated for image quality. In addition, using a high-contrast phantom (Catphan, Phantom Laboratory, Salem, N.Y., USA) and a fracture model of the femoral bone, measurements of high-contrast resolution were performed in comparison to spiral CT. With the exception of the shoulder, all joint regions including the entire spinal column could be examined. Adequate image quality could be achieved in smaller joints such as the wrist, elbow, ankle, and knee, whereas a remarkably decreased image quality was found when imaging the hip as well as the lumbar and thoracic spine. Images of the phantom study and high-contrast fracture model showed a high-contrast resolution comparable to helical CT (9 Lp/cm in xy-axis). In smaller joints, the image quality of the mobile C-arm CT imaging system (Iso-C3D) is comparable to that of helical CT. Image quality in examinations of the hip and lumbar and thoracic spine seems to be sufficient for intraoperative control studies of osteosynthesis. Problems still occur in shoulder examinations.

Functional magnetic resonance imaging of temporomandibular joint disorders

Fifty-eight temporomandibular joints (TMJs) from 40 patients with TMJ-related symptoms were examined by means of magnetic resonance scans with modified gradient echo sequences and a special double coil. This technique yielded a good spatial resolution of the intra-articular soft tissues, especially the articular disc and the bone structure of the TMJ. In combination with an incremental jaw opener, the disc-condyle complex was analysed in various closed and open mouth positions, depending on the clinical examination. Open mouth movement with differentiation of disc-condyle rotational and translation movement was demonstrated. Disturbances of TMJ motion showed interrupted condylar translation combined with mandibular deviation during open mouth movement (n = 8/58). Early phases of internal derangement of the TMJ with partial anterior disc displacement with (n = 12/58) or without (n = 2/58) reduction, total anterior disc displacement without reduction (n = 10/58), disc deformation (n = 10/58), disc adhesion (n = 2/58), condylar hypermobility (n = 6/58), condylar displacement (n = 8/58), and late phases of internal derangement of the TMJ with osteoarthrosis (n = 14/58) were clearly identified. Bilateral TMJ disorder was found in 72.5 per cent of the patients. By using motion-adapted, semi-dynamic magnetic resonance imaging (MRI), it is possible to improve the understanding of the complexity of TMJ movements.

In vivo kinematics of total knee arthroplasty. Concave versus posterior-stabilised tibial joint surface

We studied the kinetics of the knee in 20 patients (22 knees) 12 months after total knee arthroplasty (TKA), by using three-dimensional radiostereometry and film-exchanger techniques. Eleven knees had a concave (constrained) tibial implant and 11 a posterior-stabilised prosthesis. Eleven normal knees served as a control group. In the posterior-stabilised knees there was less proximal and posterior displacement of the centre of the tibial plateau during extension from 45 degrees to 15 degrees, with a decrease in the anterior translation of the femoral condyles of 4 mm at 45 degrees. There was less internal tibial rotation and increased distal positioning of the centre of the tibial plateau with both designs when compared with the normal knees, and in both the centre of the plateau was displaced posteriorly by more than 1 cm. Increased AP translation has been recorded in all prosthetic designs so far studied by radiostereometry. The use of a posterior-stabilised design of tibial insert could reduce this translation but not to that of the normal knee.

Accurate needle placement by the suction-bubble technique for hip arthrography

We present a novel, effective method for verifying intraarticular needle placement for hip aspiration and arthrography. The vacuum created by hip-joint distraction induces an easily visualized movement of air bubbles in attached tubing, thereby confirming accurate localization. The suction-bubble technique is safe, objective, and reproducible in even inexperienced hands. We report no complications of erroneous extracapsular injection of contrast in >50 cases.

[MRI arthrography of the ankle joint]

Due to its superior soft tissue contrast conventional MRI is the imaging method of choice in the evaluation of ankle joint disorders. Conventional MR imaging can accurately demonstrate normal or acutely injured ligaments; however, in subacute and chronic injury joint fluid necessary for delineation of injured ligaments is absent and MR arthrography should be performed. MR arthrography uses the intraarticular injection of contrast material to distend the joint, yielding improved discrimination of intraarticular structures. This joint distension with MR arthrography is also helpful in the staging of osteochondritis dissecans, since in cases of unstable lesions tracking of contrast material into the interface can be more easily demonstrated. Finally, high contrast and joint distension by MR arthrography improves the detection of intraarticular loose bodies, which often require surgery. MR arthrography, although invasive, may provide additional information in various ankle joint disorders.

Ankle tenography. A therapeutic imaging modality

Ankle tenography is an easily learned technique for the treatment of tenosynovitis. This article describes the procedure in detail and discusses the indications and contraindications for tenography. The anatomy of the ankle tendons is briefly reviewed. This article familiarizes radiologists with this minimally-invasive therapeutic modality so that they can offer it as an option for their referring physicians, who often have few other choices when it comes to managing patients with chronic ankle pain.

Simultaneous multilayer arthrotomography of the temporomandibular joint using photostimulable phosphor computed radiography

OBJECTIVE

To compare the image quality of photostimulable phosphor computed radiography (CR) with that of a conventional screen-film system for simultaneous multilayer arthrotomography of the temporomandibular joint (TMJ).

METHODS

X-ray attenuation, resolution and granularity was compared. Simultaneous multilayer tomography of TMJ was performed using a skull phantom and diagnostic quality of bone structures estimated. The clinical outcome is demonstrated in two typical cases.

RESULTS

X-ray attenuation was larger with CR. Granularity was more prominent in edge-enhanced CR images and was associated with inferior diagnostic quality. However, it was improved by using a higher tube voltage. Clinical CR without edge enhancement showed a similar resolution to the conventional system but this decreased with enhancement. In an enhanced arthrotomogram, the boundary between contrast medium, bone and soft tissue were clearly defined and a fibrous adhesion also easily seen.

CONCLUSION

Photostimulable phosphor CR is an acceptable alternative for simultaneous multilayer arthrotomography of the TMJ.

Evaluation of selective wrist arthrography of contralateral asymptomatic wrists for symmetric ligamentous defects

OBJECTIVE

The objective of this investigation was to study the role of selective wrist arthrography of the asymptomatic wrists of patients with unilateral wrist pain and the efficacy of three-compartment and selective-compartment injections of contrast medium into the asymptomatic wrist in demonstrating symmetric and asymmetric intercarpal ligament and triangular fibrocartilage communicating defects.

SUBJECTS AND METHODS

Wrist arthrography with bilateral three-compartment injections was performed for 62 patients with unilateral wrist pain. The numbers of bilateral intercarpal ligament and triangular fibrocartilage communicating defects were recorded. The results obtained with three-compartment injections in each wrist of these patients were compared with those obtained with single-compartment injections.

RESULTS

Bilateral three-compartment injections identified 110 communicating defects (59 in the symptomatic and 51 in the asymptomatic wrists). Midcarpal injections showed all 36 scapholunate and lunatotriquetral ligament defects that were also shown by three-compartment injections in asymptomatic wrists. However, only 26 (72%) of these 36 ligament defects were shown by radiocarpal injections. No single-compartment injection showed all triangular fibrocartilage defects that were shown by three-compartment injections. Ten bilateral symmetric triangular fibrocartilage communicating defects were shown by three-compartment injections. All 10 triangular fibrocartilage communicating defects in asymptomatic wrists were shown by radiocarpal injections. However, only five of the 10 triangular fibrocartilage communicating defects in asymptomatic wrists were shown by injection of the distal radioulnar joints.

CONCLUSION

Selective midcarpal injection of an asymptomatic wrist showed all matching defects in that wrist when only intercarpal ligament defects were found in the symptomatic wrist. Similarly, selective radiocarpal injection of an asymptomatic wrist showed all matching defects of the triangular fibrocartilage in that wrist. In either situation, routine injection of all three compartments of the asymptomatic wrist should not be necessary.

[Arthrography of the wrist joint in acute trauma]

At least 20-25% of the patients with distal radius fractures show concomitant lesions of the intrinsic ligaments of the proximal carpal row and lesions of the triangular fibrocartilage complex. A high number of these lesions cause persistent pain and discomfort, even if there is a good radiological result. Wrist arthrography as a screening method can identify these lesions and help to select the patients in whom further diagnostic and therapeutic procedures (diagnostic arthroscopy, arthroscopical refixation of the discus or SL stabilization) should be performed. Wrist arthrography also allows cartilage lesions to be detected, as well as associated fractures or lesions of the capsular ligaments. The technique of wrist arthrography in the acute traumatized wrist, which is different from wrist arthrography in patients suffering from chronic post-traumatic pain, is described in this paper.

Arthroscopy in food animal practice

Arthroscopy can be an effective technique for diagnosis and treatment of various orthopedic disorders in cattle, including septic arthritis and osteochondrosis. Cost of equipment and surgery may be prohibitive for some individuals, yet the techniques of arthroscopic surgery are proven efficacious when applied to cattle. Arthroscopic techniques may also be quite useful in the evaluation and treatment of the same disorders in sheep, goats, and camillids. The technology remains the same and applicability rests with financial constraints and the physical aspects of specific species and joints. We speculate that arthroscopy would be quite useful for exploration and treatment of the larger joints and other selected joints of these species.

Sensitivity versus specificity of phonoarthrography as an indicator for cartilage degeneration

In an attempt to update the idea of recording knee sounds, 400 osteoarthritic (OA) knees, 100 knees from a young age group (18-31 years) and 100 knees from an age-matching group (45-60 years) were recorded by a computerized device using a special program that enabled the conversion of sounds--recorded in a fixed lapse of time--to waves which were then analysed in terms of frequency/second and average amplitude. Radiological grading was done for all groups in order to compare both parameters. Reproducibility of the recordings for each knee was confirmed statistically. Phonoarthrography was found to be 100% sensitive for radiological changes and for clinically felt crepitus, simultaneously diagnosing early OA in 32.5% of subjects with no radiological changes and in 7.5% of subjects with no clinically felt crepitus. From the work it can be deduced that computerized phonoarthrography can diagnose early cases of OA and is excellent for assessing and following up cases. It may be regarded as an indicator for cartilage degeneration.

[A comparison of NMR tomography and arthrography in functional disorders of the temporomandibular joint]

PATIENTS AND METHODS

31 patients with clinically diagnosed dysfunction of the temporomandibular joint (TMJ) were examined by magnetic resonance imaging (MRI; 1.5 Tesla, TR/TE 600/30) in closed and open mouth position and functional arthrography with digital image recording.

RESULTS

Both methods agreed in the evaluation of the disc position. In 23 joints with displaced disc reposition was found in 11 cases and in 14 cases using MRI or arthrography, respectively. MRI proved to be superior in the diagnosis of sideways disc rotations. Joint hypermobility, eccentric disc displacement (n = 4) and perforation (n = 3) were shown by functional arthrography. Due to the good demonstration of osseous, muscular and discoligamentous structures, MRI as a noninvasive imaging modality is the method of choice for TMJ evaluation. Arthrography can be advantageous in complex functional disturbances or if MRI and clinical findings are inconclusive. The clinical diagnosis of disc displacement was found to be accurate in only 68% of the cases.

[Rotator cuff rupture in the shoulder impingement syndrome. Echography and arthrography: 2 diagnostic methods compared]

After briefly reviewing the shoulder impingement syndrome, the authors investigate the role of two diagnostic imaging methods, i.e., ultrasonography (US) and arthrography, in demonstrating the typical features of this condition. Over a 15 months' period, 190 patients suffering from shoulder pain were examined with arthrography; 50 of them subsequently underwent acromion plastic surgery and rotator cuff stitching. This study was aimed at comparing US and arthrographic results, applying classifiable criteria to make the most accurate diagnosis of rotator cuff tears. The lack of visibility of the rotator cuff at US was the major and clearest sign of tear (100% of cases). The association between cuff thinning and hypo/hyperechoic damaged focal areas was another major sign (in 76.19% of complete tears and in 14.28% of incomplete tears). Hyperechoic focal areas alone proved to be a false-positive finding in 5 cases, while in 11 of 19 cases normal US patterns were a false-negative finding; in 3 cases other conditions were diagnosed. To conclude, the value of US is emphasized in the screening of the painful shoulder and the use of arthrography is suggested when both clinical tests and US fail to yield enough information for a diagnosis to be made.

Changes in stiffness following short- and long-term application of standard physiotherapeutic techniques

A computer-controlled MCP joint arthrograph was developed to measure the stiffness of finger joints objectively. This was used to study the short-term (one application) and long-term (multiple applications over 6 weeks) effects of several physiotherapeutic methods on the reduction in joint stiffness. The techniques used were hot wax baths, pulsed ultrasound alone, wax baths plus pulsed ultrasound and exercise. In the short-term (i.e. after each application) wax plus ultrasound produced a statistically significant reduction in elastic torque range (P < 0.01) and dissipated energy (P < 0.05). However, the reductions in these stiffness parameters were temporary. Long-term no significant reductions in stiffness were measured. In other words, stiffness was reduced by each therapy session, but it then increased again before the next session. Wax, ultrasound alone or exercise produced no short- or long-term effects.

[Clinical use of magnification radiography in rheumatologic differential diagnosis]

Rheumatologic joint disorders were examined with high-definition microfocal magnification radiography. The magnification technique was compared to conventional radiographs (mammographic film-screen combinations). The microfocal x-ray unit had a spot size of 20-130 microns. Fourty patients with early arthritis (history of less than 18 months) were examined; x5 magnification was used. Digital luminescence radiography was employed to minimize radiation dose. Digital image processing included simulation of conventional technique and edge enhancement. Magnification radiographs and conventional technique were evaluated. In 20/40 patients articular lesions were detected. Magnification radiography gave additional information in 14/20 patients: in 5/14 patients lesions were seen only with magnification radiography (erosions n = 3, loss of the cortical white line n = 2), in 9/14 patients the extent of the lesions could be evaluated better. Hence, magnification radiography proved a valuable mean in early diagnosing and evaluating rheumatic disease.

Quantitative stress radiography for diagnosis of anterior cruciate ligament deficiency. Comparison between manual and instrumental techniques and between methods with knee flexed at 20 degrees and at 90 degrees

A portable stress-applying device for stress radiography was developed for daily clinical use. Using this device, stress radiography for the diagnosis of the anterior cruciate ligament (ACL) deficiency was performed with the knee flexed at 20 degrees and at 90 degrees. A 100-N force was chosen as a standardized stress. The subjects were classified into four groups: the manually tested ACL-deficient group (32 knees), the manually tested control group (80 knees), the instrumentally tested ACL-deficient group (14 knees), and the instrumentally tested control group (34 knees). There was no statistical difference in the reliability (sensitivity, specificity, and accuracy) of stress radiography between the manual technique and the instrumental technique. When stress radiography with the knee flexed at 20 degrees and that at 90 degrees were compared, the former was more reliable than the latter. As the manual technique is compromised by a lack of standardization in applied force, a mechanical device is required in quantitative stress radiography. The reliability of stress radiography with the knee flexed at 20 degrees is considered high enough to warrant dispensing with further stress radiography with the knee flexed at 90 degrees for diagnosing ACL deficiency.

Measurements of carpal bone angles on lateral wrist radiographs

Measurements of carpal bone angles on lateral wrist radiographs can be of assistance in the diagnostic evaluation of wrist malalignment. A series of 75 normal wrists was examined by use of a standardized radiographic technique. The normal carpal bone angles were determined using the bone axes with the least observer variability (mean and range): radiolunate, -1.02 (-10 to 12), radioscaphoid, 51.80 (35 to 65), and scapholunate, 50.77 (36 to 66). Normal mean values and ranges for intercarpal bone angles may be of assistance in the diagnostic evaluation of ligamentous injury to the wrist.

[The methods and place of digital subtraction arthrography of the hip in detecting endoprosthesis loosening]

Digital subtraction arthrography (DSAr) of the operated hip is presented and compared to nuclide bone scan and plain radiograph. Surgical proof was obtained in 47 patients. In the evaluation DSAr proved to be superior to nuclide bone scan and plain radiograph. DSAr had the best predictive value in the diagnosis of loosening of a prosthesis. In contrast to conventional arthrography there is a better differentiation between the contrast medium, the prosthesis, the acrylic cement and the bone by using DSAr. In addition DSAr presents the advantage of postprocessing, especially pixel shift.

MRI in the evaluation of patients with suspected instability of the shoulder joint including a comparison with CT-arthrography

Thirty-two patients with clinical suspicion of shoulder instability were the subject of this assessment of MRI (1.5 T G. E. Signa) and its comparison with CT-arthrography (GE8800 and GE9800) of the shoulder. Twenty-seven patients had a final diagnosis established by arthroscopy and five by arthrotomy. The imaging examinations were interpreted independently by three radiologists blinded against history, surgical diagnosis and results of the compared test. The statistical analysis included ROC-curves, sensitivity, specificity and accuracy as well as predictive values. The significance of the comparative results was assessed by the McNemar Sign test. MRI showed significantly better diagnostic results in the evaluation of labral structures (sensitivity 85%, specificity 90%, accuracy 88%) and humeral head impression fractures (75, 82, 78 %). None of the tests were of sufficient diagnostic value to identify capsular abnormalities. CT and MRI results regarding the biceps tendon and loose bodies were similar, however, statistically not significant. MRI proved to be of high diagnostic value in the assessment of the unstable shoulder and compared favorably with CT-A.

Exposure factors and screen-film combinations in temporomandibular joint radiography

Exposure factors and screen-film combinations providing optimal quality are identified for transcranial and transpharyngeal temporomandibular joint views, using conventional intra-oral radiographic equipment without grids. Standardized transcranial and transpharyngeal views, using a fixed whole cadaver head, were performed. Ten readily available screen-film combinations, ranging in nominal speed 20-600, were exposed over 40-100 kV. Films were blindly and independently order ranked by three observers on the basis of sharpness and contrast of cortical outline, trabecular detail, and visualization of adjacent bony structures. Preferred screen-film combinations as a function of kV, preferred kV levels for each screen-film combination, and overall ranking irrespective of kV or screen-film combination, were established. Accepting the use of the lowest radiation dose possible for diagnostically useful radiographs but imposing arbitrarily an upper limit of 20 mGy, it was found that exposures between 50 kV and 70 kV gave the optimal result for both techniques. The amount of scattered radiation in the emergent beam differs greatly between the two techniques. The most favoured combinations for the transpharyngeal technique used screens of fine resolution. Min-r/ortho M screen and film with nominal speed 40 at 60 kV gave 8.0 mGy skin dosage at 0.8 seconds exposure; the same combination at 50 kV was the most favoured, but with skin dosage calculated at 16.7 mGy for 3.0 seconds exposure. For the transcranial technique, medium speed screens providing better differentiation of scattered radiation beams and increased speeds were preferred. Most favoured for image quality was the Lanex Fine/T-Mat G combination at 60 kV giving 17.5 mGy skin radiation dose at 1.75 seconds exposure.(ABSTRACT TRUNCATED AT 250 WORDS)

[A new digital radiology system. The technical considerations and clinical experience]

The authors report their experience with a new digital X-ray film processing system, particularly used in the diagnosis of breast, chest, joint and bone pathologic conditions. The technical features of the system are described, and the results are reported which appear as the most significant in mammography, with better visualization of both microcalcifications and small detail images. The above results are due to the possibility of broad contrast variations and of processing basal X-ray images. The possibility is also stressed of improving the diagnostic value of a technically incorrect radiograph, especially if overexposed, with subsequent dose saving.

[Radiology of the temporomandibular joint]

Different radiological techniques have been developed through the years within the realm of studies on the temporomandibular joint, which have implemented significant improvements in diagnosis by professionals in stomatology. Some of the most modern radiographical techniques, such as computerized tomography (CT) or magnetic resonance image (MRI) are not yet regularly used in our country for the diagnosing of temporomandibular dysfunctions. However, it is quite possible that in the near future, this type of techniques may be more widely handled, with resultant benefits for ailing patients.

Temporomandibular joint arthrography without fluoroscopy

An arthrographic technique for the temporomandibular joint that can be performed in a dental surgical room is described. This technique utilizes a dental radiographic unit and extraoral cassettes for visualization of the needle tip in the inferior synovial space for arthrography. The radiographic visualization is combined with tactile discernment of the needle tip on the mandibular condyle. The successful application of these two methods makes fluoroscopy unnecessary. After an initial success rate of 81% (34 of 42 attempts), we have used the technique successfully in more than 100 cases. Most of the problems encountered with this technique can be attributed to initial operator inexperience. This technique is not suggested as a replacement for fluoroscopy. However, it is a convenient, economical technique that can be used in the dental surgical room by trained clinicians when arthrography is indicated to determine meniscal-condylar relationships and meniscal perforations.