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Biomedical subjects

J Hodler

Publications and source records attributed to J Hodler.

At least 91 records · Page 5Linked to original sources

Current status of imaging of articular cartilage.

Various imaging methods have been applied to assessment of articular cartilage. These include standard radiography, arthrography, CT, CT arthrography, ultrasonography, and MR imaging. Radiography remains the initial musculoskeletal imaging method. However, it is insensitive to early stages of cartilage abnormalities. MR imaging has great potential in the assessment of articular cartilage, although high-quality scans are required because imaging signs of cartilage abnormalities may be subtle. The potential and limitations of various sequences and techniques are discussed, including MR arthrography. The role of the other imaging methods in assessment of articular cartilage appears to be limited.

Cartilage Diseases↗

[Magnetic resonance tomography (MRI) of ligament injuries of the upper ankle joint].

This paper discusses MR imaging in injuries to the lateral collateral ankle ligaments. Based on recent publications and our own results MR imaging may be useful for demonstration of ankle ligament tears. However, clinical outcome can probably not be predicted by such diagnosis. MR imaging may still be useful in certain settings, such as suspected additional trauma to medial ligaments, bone, or articular cartilage. In chronic pain MR imaging may be indicated for demonstration of articular bodies, occult fractures, significant cartilage damage, tendon injuries and dislocations, and soft tissue scars.

Ankle Injuries↗

Posterolateral aspect of the knee: improved MR imaging with a coronal oblique technique.

PURPOSE: To determine if angling the coronal plane in magnetic resonance (MR) imaging of the knee increases the conspicuity of the posterolateral structures. MATERIALS AND METHODS: A coronal oblique MR imaging sequence performed parallel to the popliteal tendon proximally was added to our routine study in patient knee examinations. One hundred patients (age range, 12-72 years) underwent MR imaging. RESULTS: Coronal oblique images depicted the arcuate ligament in 46%, the fabellofibular ligament in 48%, and the fibular origin of the popliteal muscle in 53% of the patients, whereas standard coronal images depicted these in 10%, 34%, and 8% of the patients, respectively. Sagittal oblique images did not adequately depict these structures. CONCLUSION: Depiction of the structures in the posterolateral aspect of the knee was optimal on coronal oblique images. We advocate obtaining coronal oblique T2-weighted images in patients with either posterolateral knee pain or suspected injury to the posterolateral ligamentous structures.

Adolescent↗

Clinical examination and magnetic resonance imaging in the assessment of ankle sprains treated with an orthosis.

This is a prospective clinical study of treatment of ankle sprains with an ankle brace that permits ankle dorsiflexion and plantarflexion of 20 degrees, but limits inversion and eversion for 6 weeks. The ankle brace is followed by physiotherapy for another 6 weeks. Thirty patients were evaluated with clinical examination and magnetic resonance (MR) imaging before treatment and after 12 weeks of treatment. MR imaging revealed acute tears in the anterior talofibular ligament in all 30 ankles (100%) and tears in the calcaneofibular ligament in 25 of 30 ankles (83%). At 12 weeks after injury, MR evidence of healing was present for the anterior talofibular ligament in 22 of 30 ankles (73%) and for the calcaneofibular ligament in 23 of 25 ankles (92%). Postural sway analysis after therapy was used to quantify functional stability of the ankle. There was no correlation with MR findings, but there was a correlation with the subjective impression of functional instability. Twenty-eight of 30 patients (93%) had a functionally stable ankle after 12 weeks of treatment. MR findings after ankle sprain could not predict clinical outcome.

Adult↗

Titanium implant for the osteosynthesis of massive allograft reconstruction to improve follow-up by magnetic resonance imaging.

In twelve patients with local aggressive or malignant bone tumors allograft reconstruction after limb sparing procedures were performed using titanium implants for osteosynthesis. In eleven of these patients magnetic resonance imaging studies could be completed. Distortions of the images were limited to the vicinity of the implants and did not preclude detailed analysis of the gross anatomy and of fine articular structures involving and adjacent to the allografts used. Titanium implants therefore can be recommended whenever magnetic resonance imaging can be anticipated to be of importance for follow-up studies, such as after limb saving procedures for malignant musculoskeletal tumors. Aspects of high interest and importance in such cases include early recognition of local recurrence, bone fusion and healing of soft tissue structures, incorporation of allografts, and viability of cartilage.

Adolescent↗

Correlation of MR imaging, CT arthrography, and arthroscopy of the shoulder.

Rotator cuff tears and instability of the glenohumeral joint are a common cause of chronic shoulder pain and disability. Currently CT arthrography is the method of choice to evaluate the extent of osseous and soft tissue abnormalities. This study was undertaken to determine if magnetic resonance imaging was able to depict post-dislocation abnormalities and rotator cuff pathology and if MRI can replace CT arthrography. Sixty four patients, who were operated on for the first time (arthroscopy or arthrotomy) between November 1986 and July 1991, were compared in a blinded fashion with the results of MR imaging in 40 cases and of CT arthrographies in 24 cases. For the evaluation of rotator cuff tears MRI proved to have a sensitivity of 83.3% and an accuracy of 90.3%. Labral pathology was depicted with a sensitivity of 69.2% and an accuracy of 87.1%. In cases involving a Hill-Sachs lesion the sensitivity of MRI was 90% and the accuracy 95%. MR imaging is an accurate method in the evaluation of rotator cuff pathology and to some extent labral abnormalities.

Adolescent↗

[Knee problems--imaging techniques].

Standard radiographs still represent the standard imaging method in knee abnormalities. Major advantages include high spatial resolution, low cost, high availability and standardized imaging technique. Because there is an increasing pressure on the cost of health care, additional imaging should only be employed based on a working hypothesis. In most cases MR imaging is most suitable for further diagnosis. In internal knee derangements MR imaging has been shown to have a high negative predictive value, thus obviating unnecessary surgery. MR imaging also is the imaging method of choice in the detection and follow-up of arthritis, in the detection, staging and follow-up of malignant neoplasms, and in the detection of occult fractures. Ultrasonography is useful in the characterization of superficial soft-tissue abnormalities, but has not gained high acceptance in searching for internal derangements of the knee. Scintigraphy is competing with MR imaging in the early detection of bone abnormalities and for follow-up. However, it is less expensive and can be employed for the evaluation of multilocular processes. CT has a limited role in the evaluation of complex fractures mainly of the tibial plateau.

Arthritis↗

[Aortic elongation: merely mimicked in increased thoracic kyphosis? radiologic-pathologic correlation].

The purpose of this investigation was to demonstrate that the radiologically "elongated" thoracic aorta corresponds to an increase in anatomical aortic length and is not merely mimicked by increased thoracic kyphosis with shortening of the thoracic cage. 50 consecutive autopsies were included (age at death: 33-90 years, mean 65.1 years). Radiologically, mediastinal width was measured on in vivo posteroanterior radiographs, and a scoring system was used to assess aortic elongation semiquantitatively. The angle of kyphosis was measured on lateral in vivo radiographs that had been obtained in a standardized fashion. With relative aortic length defined as anatomical aortic length divided by body length, there was a statistically significant correlation with radiological mediastinal width and the radiological scoring system (p < 0.001). However, there was no statistically significant correlation between relative aortic length and radiological mediastinal width (p = 0.47) and the radiological scoring system (p = 0.56). Therefore, the radiological diagnosis of aortic elongation appears to correspond to true aortic lengthening.

Adult↗

[Quality assurance in diagnostic radiology].

Quality assessment is increasingly important in medicine in general as well as in diagnostic imaging. Quality in medicine includes state-of-the-art procedures, patient satisfaction, economic aspects, safety, and access to adequate care for the entire population. In order to measure quality more specifically in diagnostic imaging, several levels of efficacy have been defined. These include technical efficacy, diagnostic accuracy, diagnostic-thinking efficacy, therapeutic efficacy, outcome efficacy, and societal efficacy. Major factors in improving quality in diagnostic imaging include the expanded access to and use of databases, progress in continuing education, and increased research activities.

Diagnostic Imaging↗

Fast spin-echo inversion-recovery imaging versus fast T2-weighted spin-echo imaging in bone marrow abnormalities.

RATIONALE AND OBJECTIVES: The purpose of this investigation is to compare a fat-suppressed T2-weighted fast spin-echo (FSE) sequence in bone marrow abnormalities with an FSE STIR sequence that recently has become commercially available. METHODS: Fast spin-echo images (repetition time [TR], 3500-5000 mseconds; echo time [TE], 96-114 mseconds) and FSE STIR images (TR, 3000-5000 mseconds; TE, 32-40 mseconds; inversion time [TI], 140-150 mseconds) were compared quantitatively and qualitatively calculating signal-to-noise ratios (SNRs), contrast-to-noise ratios (CNRs), and lesion conspicuity and using a qualitative scoring system. RESULTS: Signal-to-noise ratio (mean +/- standard deviation) was 36.4 +/- 19.3 for the FSE and 29.0 +/- 15.9 for the FSE STIR images (P = .002). Contrast-to-noise ratio (mean +/- standard deviation) was 18.7 +/- 14.3 for the FSE and 20.3 +/- 16.0 for the FSE STIR images (P = .45). Lesion conspicuity (mean +/- standard deviation) was 1.7 +/- 1.5 for the FSE and 3.5 +/- 4.0 for the FSE STIR images (P = .025). The most important difference in the qualitative evaluation related to the better signal homogeneity on the FSE STIR images. CONCLUSIONS: Fast spin-echo STIR images may be preferable to FSE images with fat suppression due to better image homogeneity and lesion conspicuity.

Adolescent↗

Assessment of articular cartilage thickness of the humeral head: MR-anatomic correlation in cadavers.

OBJECTIVE: The purpose of our study was to evaluate several commonly used MR sequences to determine how accurately each demonstrates the thickness of the articular cartilage of the humeral head. MATERIALS AND METHODS: Ten cadaveric shoulders (age at death, 58-92 years; mean, 79 years) were imaged with fat-suppressed transaxial T1-weighted spin-echo three-dimensional gradient-recalled sequences, both before and after injection of 12 ml of diluted gadopentetate dimeglumine. Articular cartilage was measured to the nearest 10th of a millimeter on the MR images and corresponding anatomic sections. RESULTS: Cartilage could not be differentiated from surrounding structures in 14 of 112 locations (13%) on the spin-echo images obtained without contrast material, in 4 of 112 locations (4%) on the spin-echo images obtained with contrast material, in 4 of 112 locations (4%) on the gradient-echo images obtained without contrast material, and in 6 of 112 locations (5%) on the gradient-echo images obtained with contrast material. Mean true cartilage thickness was 1.23 mm (SD, 0.52 mm). The mean MR-anatomic differences (absolute values) were 0.38 mm for the spin-echo images obtained without contrast material, 0.42 mm for the spin-echo images obtained with contrast material, 0.49 mm for the gradient-echo images obtained without contrast material, and 0.37 mm for the gradient-echo images obtained with contrast material. There was a tendency to overestimate thin cartilage and to underestimate thick cartilage. CONCLUSION: Several of the routinely used MR sequences, with and without intraarticular contrast medium, may cause errors in the assessment of the articular cartilage of the humeral head. Some of these errors result from either insufficient contrast between cartilage and surrounding structures or inadequately concentrated contrast medium.

Aged↗

MR arthrography of the hip: improved imaging of the acetabular labrum with histologic correlation in cadavers.

OBJECTIVE: The objective of this study was to correlate findings on conventional MR imaging and MR arthrography of the hip with pathologic findings in cadavers with abnormal labra to determine (1) the efficacy of MR imaging in assessing labral degeneration, (2) whether delineation of the labrum from the joint capsule is possible, and (3) if the conspicuity of surface abnormalities of the labrum is improved by administering intraarticular contrast material. MATERIALS AND METHODS: Twelve cadaveric hip joints were obtained from elderly cadavers. Each hip was examined using fat-suppressed three-dimensional spoiled GRASS (gradient-recalled acquisition in the steady state) (SPGR) imaging and T1-weighted spin-echo imaging before and after intraarticular injection of contrast material. Thirty-six labral sections (three from each hip joint) were evaluated histologically to determine the labral-capsular relationship, the presence of degeneration, and the configuration of the labral base. These findings were correlated with the results of a blinded MR evaluation of these sections. RESULTS: Delineation of the labrum from the adjacent joint capsule was possible on SPGR and T1-weighted MR arthrographic images (34 of 36 and 33 of 36 specimens, respectively), but was not consistently possible on standard SPGR and T1-weighted MR images (7 of 36 and 4 of 36 specimens, respectively). The sensitivities and specificities of the various MR sequences in evaluating labral degeneration varied from 50% to 67%, and from 25% to 94%. Increased signal at the base was common in both the normal (n = 12) and the abnormal (n = 24) labrum. CONCLUSION: Conspicuity of the acetabular labral complex is enhanced with the intraarticular administration of contrast material. Although MR arthrography did not improve our specificity for diagnosing labral degeneration, the detection of surface abnormalities, particularly those near the base, was significantly improved.

Acetabulum↗

[Ultrasonography and magnetic resonance tomography (MRI) of tendon injuries].

Both ultrasound and MR imaging have become increasingly important for the assessment of tendon abnormalities. Ultrasound is widely available and is mainly suitable for emergency situations in traumatology and as a screening method. For soft tissue imaging only up-to-date sonographic equipment should be used. Moreover, the examiner's experience is crucial for adequate results. MR imaging is not as easily available. However, it is more reproducible and may be indicated in a preoperative situation. Most publications about sonography and MR imaging deal with the rotator cuff and the Achilles tendon. Fewer investigations relate to the posterior tibial tendon, the extensors of the knee and the proximal and distal biceps tendon. The role of ultrasound and MR imaging in abnormalities of these structures is discussed based on the literature and our own experience.

Achilles Tendon↗

MR imaging versus alternative imaging techniques.

MR imaging is the method of choice in evaluating a large number of soft-tissue abnormalities; however, it has certain draw-backs, some of which may make other imaging methods more suitable. MR imaging is more expensive than alternative imaging methods; it may not be affordable for screening purposes and for diagnoses obtainable by less expensive imaging methods. In addition, immediate scheduling is not always possible for MR imaging, and an MR scanner may not be available close to the patient's home, which may be important for imaging follow-up. These factors support the use of other imaging modalities, with sonography frequently being the appropriate choice. In some situations, mainly in the presence of certain biomedical implants and devices, MR imaging is contraindicated. Additionally, under some circumstances patient access may be difficult during MR imaging; sonography and CT therefore are preferable (as for imaging guided biopsy). Moreover, some artifacts, such as motion artifacts, may have less relevance in other imaging methods (such as sonography), which may be important in noncooperative patients and children. MR imaging may not be specific in tumors and infection; this deficiency is shared with most alternative imaging methods, with the exception of scintigraphy in selected indications. Lastly, standard radiography and CT commonly are superior to MR imaging in diagnosing calcification and abnormalities of cortical bone. Consequently, in selected cases and for screening purposes, methods other than MR imaging should be considered for depicting soft-tissue structures.

Artifacts↗

[Magnetic resonance tomography of the hand: current status].

Magnetic resonance imaging (MRI) is an established imaging method in abnormalities of the wrist. Inherent advantages of this imaging method such as the lack of ionizing irradiation, the free choice of imaging planes and its excellent contrast resolution have been enhanced by the introduction of surface coils and new sequences. These developments result in an improved spatial resolution, allowing imaging of small structures such as the triangular fibrocartilage. There is a number of established indications for MRI of the wrist, e.g. diagnosis of avascular necrosis, follow-up after carpal tunnel surgery and imaging of soft tissue masses. Increasingly, MRI can be used for the diagnosis of intercarpal ligament tears as well. The diagnostic capabilities of MRI of the wrist are discussed, based on personal experience and a review of the literature.

Carpal Tunnel Syndrome↗

[Is the "classical" release of the flexor retinaculum in carpal tunnel syndrome obsolete?].

Carpal tunnel release used to be the standard treatment for carpal tunnel syndrome. However, some authors now prefer reconstruction of the transverse carpal ligament, due to suspected palmar dislocation of the median nerve in wrist flexion after simple ligament release. In this retrospective study the topographic location of the median nerve after release is investigated and an attempt made to find a correlation with the postoperative clinical outcome. In computed tomography no palmar subluxation of the nerve was found, even in a patient with a poor clinical result.

Adult↗

[Preoperative magnetic resonance tomography in chronic osteomyelitis of the extremities].

39 patients with bone and joint infections of the extremities were examined with magnetic resonance imaging (MRI) in view of an operative procedure. Patients with hip affections and patients with nonoperative treatment were excluded; therefore, 21 patients including 12 post-traumatic and 9 hematogenous cases of chronic osteomyelitis form the study group. MRI findings were verified at operation. Typical MRI findings were: intraosseous abscess (n = 15), extraosseous abscess (n = 9), communication of both (n = 7), edema of bone marrow (n = 9), soft tissues changes (n = 6) and fluid-surrounded sequestrum (n = 6). 83% of the post-traumatic cases had an intraosseous abscess, 67% of the hematogenous cases an edema of bone marrow. MRI improves preoperative planning considerably by sensitive depiction of pathological findings in three planes. To obtain information about activity of the process, scintigraphy is needed in addition. In some cases computer tomography (CT) is helpful to find small sequestra.

Adolescent↗

Juvenile chronic arthritis: imaging of the knees and hips before and after intraarticular steroid injection.

Intraarticular steroid therapy in juvenile chronic arthritis (JCA) is performed because of high local efficacy with few side effects. Imaging is used for initial evaluation and for monitoring of treatment response. The aim of this study was to compare imaging findings in diseased hips and knees before and after therapy. A prospective study was performed on 10 patients (15 joints) scheduled for intraarticular therapy. Pretherapeutic assessment included clinical work-up, radiographs, ultrasound (US), and magnetic resonance imaging (MRI) of affected joints. Following therapy, clinical and sonographic examinations were performed at 1 week and 1 month. MRI was repeated at 1 month. MRI and US demonstrated pannus formation and effusion, but differentiation was less distinct on US. Popliteal cysts and lymph nodes were visible in both modalities. MRI additionally revealed articular cartilage loss and subchondral cysts, not shown by US. Epiphyseal overgrowth and osteopenia were best seen radiographically. At present MRI is the best tool to assess the inflammatory changes of the joints in JCA. Initial staging of the joints may be done with plain films and MRI. US is useful to assess effusion and pannus and may be used to monitor treatment response.

Administration, Topical↗