[Reproducibility of the radiographic analysis of dysplasia of the femoral trochlea. Intra- and interobserver analysis of 68 knees]

PURPOSE OF THE STUDY

The relation between patello-femoral instability and trochlear dysplasia was identified by Dejour. Trochlear dysplasia, diagnosed on knee lateral Xray when the trochlear groove crosses both femoral condyles (the so-called "crossing sign"), must be corrected to improve patello-femoral stability. However surgery should be related to the severity and the shape of trochlear dysplasia, underlining the importance of a reproducible classification. The aim of this study was to establish intra and inter-observer reliability of Dejour's radiographic criteria.

MATERIAL

68 preoperative exact knee profile radiographs were harvested from clinical records of 64 patients who underwent trochleoplasty because of patello-femoral instability and trochlear dysplasia. On these 68 views, the crossing sign was identified by the senior surgeon (F.G.) who performed or supervised surgery.

METHOD

The 68 radiographs were examined independently by 7 observers (2 juniors, 5 seniors) in order to assess interobserver agreement. Two juniors repeated the observation to test intraobserver agreement. Reproducibility for categorical data (7 shapes of trochlea according to Dejour (3 for dysplasia)) was evaluated by Kappa statistics, and for numerical data (depth and anterior projection of the trochlear groove with respect to anterior femoral cortex) we used the interclass correlation analysis.

RESULTS

Two out of the 7 observers rated all the 68 trochleas as dysplastics. The 5 others rated as normal 1 to 6 trochleas out of the 68. None of the 68 trochleas were recognized with the same shape by the 7 examiners. At best, 6 observers agreed on the same shape and for only 12 trochleas. Disagreement was mostly related to mistakes between type I and type II of dysplasia. For trochlear morphology interobserver agreement was slight (Kappa = 0.17) and intraobserver agreement was fair (Kappa = 0.3). The mean prominence of the trochlea was 3 +/- 2.1 mm [-6 to 10], and the mean trochlea depth was 1 +/- 1.9 mm [0 to 11]. These measurements were more reliable since the interclass correlation coefficients were respectively 0.62 and 0.38. The level of experience of the observers had no influence for categorical or numerical data.

DISCUSSION

Our results indicated a low interobserver agreement for trochlear shape identification according to Dejour. The most reliable criteria was measurement of the trochlear prominence which was mostly pathological in our series. The "crossing sign" was reliable to diagnose dysplasia since the probability to rate as normal a true dysplastic trochlea was only 3.1 per cent. However, once the dysplasia diagnosed, this classification gave inconsistent results to select the trochlear shape, particularly for type II. To improve reproducibility we propose to diagnose a type II only when 5 millimeters separate the crossings between the medial and lateral condyles.

CONCLUSION

We recommend to use anterior projection of the trochlear groove to rate trochlear dysplasia and to determine the adequate type of trochleoplasty: elevating of the lateral facet if non prominent or deepening of the groove when prominent.

[Uncommon etiology of extradural hematoma]

Intracranial or spinal epidural hematomas are almost always of post-traumatic origin, and rarely related to rupture of a dural vascular malformation or a hemostasis disorder. We report a case of spontaneous cerebral epidural hematoma observed in a young girl with homozygous sickle cell disease. After analysis of post-operative cerebral MRI, showing skull bone infarction inside and around the bone flap, it was considered that the skull bone infarction could be responsible for a diploic venous thrombosis with subsequent "spontaneous" epidural hematoma.

[Malignant melanoma of soft tissues. Apropos of a case]

A case of malignant melanoma of the quadriceps tendon is reported. This is an uncommon soft tissue sarcoma of melanocytic origin. The appearance on MRI depends on its melanin content. The microscopic appearance is distinctive and prognosis is poor. This tumor should be kept in mind when a nodular lesion is detected in specific tendon or aponeurosis.

Extrinsic and intrinsic ligaments of the wrist: normal and pathologic anatomy at MR arthrography with three-compartment enhancement

The ligaments of the wrist have been demonstrated with magnetic resonance (MR) imaging by many authors. Distinction has been made between the extrinsic, or radiocarpal and ulnocarpal, ligaments and the intrinsic, or intercarpal, ligaments. The stability of the wrist depends on numerous ligaments: The volar ligaments are important stabilizers of the wrist, whereas the dorsal ligaments are less crucial for wrist stability. An MR imaging protocol that demonstrates these structures with high resolution has been developed. Cadaveric wrists are imaged with a spoiled gradient-recalled-echo volume-acquisition technique with fat suppression after three-compartment enhancement with a contrast agent containing gadolinium. The specimens are then sectioned, and the anatomic and pathologic findings are correlated with the findings on the MR images. The extrinsic and intrinsic ligaments of the wrist are clearly demonstrated with this technique. This protocol was designed for anatomic study and promotes understanding of the anatomy and biomechanics of the wrist; it is not intended for clinical use.

Percutaneous vertebroplasty: state of the art

Vertebroplasty is an effective new radiologic procedure consisting of the percutaneous injection of a biomaterial, usually methyl methacrylate, into a lesion of a vertebral body. This technique allows marked or complete pain relief and bone strengthening in most cases. The principal indications for vertebroplasty are osteolytic metastasis and myeloma, painful or aggressive hemangioma, and osteoporotic vertebral collapse with debilitating pain that persists despite correct medical treatment. Radiography and computed tomography must be performed in the days preceding vertebroplasty to assess the extent of vertebral collapse, the location and extent of the lytic process, the visibility and degree of involvement of the pedicles, the presence of cortical destruction or fracture, and the presence of epidural or foraminal stenosis caused by tumor extension or bone fragment retropulsion. Leakage of methyl methacrylate during vertebroplasty may cause compression of adjacent structures and necessitate emergency decompressive surgery; thus, the procedure should be performed only in a surgical center. The decision to perform vertebroplasty should be made by a multidisciplinary team because the choice between vertebroplasty, surgery, radiation therapy, medical treatment, or a combination thereof depends on a number of factors. Radiologists need to be aware of the various indications for vertebroplasty and of potential future developments and applications of the procedure.

Magnetic resonance imaging in focal myositis

We describe 4 cases of focal myositis of the lower leg in which magnetic resonance imaging (MRI) was useful and sensitive in clearly revealing the detailed anatomic extent of muscle change and in guiding muscle biopsy. We also observed a correlation between MRI findings and severity of both clinical and histological manifestations, suggesting that MRI may provide prognostic criteria in focal myositis. MRI may be a helpful, noninvasive test for the followup of focal myositis, in assessing disease progression or resolution.

CT scan texture analysis of the distal radius: influence of age and menopausal status

OBJECTIVES

To gain information on bone architecture by performing bone texture analysis in a sample of women covering a broad age range.

PATIENTS AND METHODS

We studied 29 healthy women aged 23 to 80 years (55 +/- 18 years), 19 of whom were postmenopausal. None was taking drugs known to influence bone mass or bone metabolism. Computed tomography of the nondominant distal radius was performed with 1 mm slice thickness and 1 mm gap. Four consecutive coronal and four consecutive axial sections were selected for each patient and entered into a PC-type computer. Bone texture was evaluated using grey level run length analysis (five parameters), differential local variation analysis (four parameters), fractal analysis (two parameters), trabecular network extraction and three-dimensional relief characterization. The mean of each study parameter for the four coronal sections and for the four axial sections was calculated. Absorptiometry was done in 16 patients.

RESULTS

Linear correlations with age were strongest (P < 0.001) for parameters measured on coronal sections by trabecular network extraction, i.e., trabecular bone volume (r = -0.68), trabecular plate separation (r = -0.65), total skeletal length (r = -0.71), number of nodes (r = 0.73), number of node-node segments (r = -0.74) and trabecular bone pattern factor (r = 0.71). Also, these parameters were significantly different between premenopausal women (33 +/- 9 years) and postmenopausal women (67.3 +/- 9 years). Correlations between bone mineral density and texture parameters were few in number and modest in strength, suggesting that the parameters measured may reflect bone structure rather than bone mass.

CONCLUSION

Bone texture in women undergoes changes with advancing age that may reflect alterations in bone microarchitecture.

Magnetic resonance imaging of the forearm: cross-sectional anatomy in a cadaveric model

RATIONALE AND OBJECTIVES

Compartmental anatomy of the forearm is complex and controversial. The purpose of this investigation was to demonstrate via magnetic resonance the anatomy of forearm compartments and their preferential ways of communication in a human cadaveric model.

METHODS

Twelve forearm spaces (11 muscles and one intermuscular) were injected with a solution containing gadopentetate dimeglumine. The extent and distribution of leakage were evaluated on axial fat-suppressed T1-weighted spin-echo images. The findings were related to known descriptions of compartmental anatomy of the forearm.

RESULTS

Contrast leakage occurred mostly into the intermuscular space and into the muscles adjacent to the injected muscle. A frank communication within the classically described three forearm compartments (volar, radial, and dorsal) was not present. The interosseous membrane was not an absolute barrier between flexor and extensor compartments.

CONCLUSION

The classic description of three forearm compartments may not be sufficient to explain distribution of soft tissue abnormalities.

Acetabular labrum: MRI in asymptomatic volunteers

PURPOSE

The purpose of this study was to describe the MR appearance of the acetabular labrum in asymptomatic hips on high resolution MRI.

METHOD

Fifty-two hips in 46 asymptomatic volunteers with an age range of 15-85 years were evaluated with coronal and axial T1-weighted and T2-weighted sequences. The shape, margin, size, and signal intensity of the acetabular labrum were analyzed.

RESULTS

The labrum was absent in its anterosuperior aspect in five hips (10%). Intralabral regions of intermediate of high signal intensity were detected in 30 hips (58%) imaged with T1-weighted and proton density-weighted sequences. Intralabral linear hyperintense foci reaching the articular surface and consistent with a labral tear were detected in four labra on T2-weighted images. Intralabral microcysts were seen in three labra.

CONCLUSION

The MR appearance of the hip labrum is varied in asymptomatic volunteers. Intralabral increased signal intensity and absent anterosuperior labra are especially frequent and may represent asymptomatic lesions or normal variations.

Collateral ligaments of the elbow: conventional MR imaging and MR arthrography with coronal oblique plane and elbow flexion

PURPOSE

To determine the best plane and position of the elbow for optimal visualization of normal and abnormal collateral ligaments with conventional magnetic resonance (MR) imaging and MR arthrography, to determine the normal appearance of the collateral ligaments at MR arthrography and to assess use of MR arthrography in evaluation of collateral ligamentous lesions.

MATERIALS AND METHODS

Nine cadaveric elbow specimens were imaged with and without intraarticular administration of gadolinium-containing solution in several planes that were identified as potentially useful in a pilot study in two specimens. MR imaging findings were compared with anatomic findings.

RESULTS

Normal and abnormal ligaments were best depicted in a 20 degrees posterior oblique coronal plane in relation to the humeral shaft with the elbows extended and a coronal plane aligned with the humeral shaft with the elbows slightly flexed (20 degrees-30 degrees of flexion). Gadolinium enhancement improved the delineation of normal and abnormal ligaments on T1-weighted images in each case.

CONCLUSION

The posterior oblique coronal plane with the elbows extended or the coronal plane aligned with the humeral shaft with the elbows slightly flexed allows accurate assessment of the collateral ligaments. Gadolinium-enhanced MR arthrography of the elbow seems to be a promising technique.

MR arthrography of the elbow: normal anatomy and diagnostic pitfalls

PURPOSE

Our goal was to determine the normal MR arthrographic appearance of the elbow and to identify the potential diagnostic pitfalls of this technique.

METHOD

MRI with intra-articularly administered gadopentetate dimeglumine was performed in seven elbow joints derived from cadavers. Coronal, sagittal, and axial SE T1-weighted images with fat suppression and coronal 3D SPGR images with fat suppression were obtained in each elbow. The elbows were then sectioned.

RESULTS

This technique allowed depiction of the cartilaginous surfaces of the elbow joint as well as clear delineation of the inner surface of the collateral ligaments. Potential diagnostic pitfalls included fat pads projecting into the joint, synovial folds, and cartilaginous pseudoerosions.

CONCLUSION

MR arthrography allows clear delineation of the intraarticular structures of the elbow. However, diagnostic pitfalls exist that increase the difficulty of interpreting MR arthrographic images.

Percutaneous vertebroplasty in patients with osteolytic metastases or multiple myeloma

Osteolytic metastases and spinal myeloma lesions are difficult to treat because they denote disseminated malignant disease. The pain-relieving and other effects of radiation therapy are delayed. We evaluated short- and medium-term outcomes of vertebroplasty in this indication, in patients with severe or excruciatingly severe pain (McGill-Melsack score 4 or 5) unresponsive to narcotics.

PATIENTS AND METHODS

forty vertebras were treated in 37 patients including 29 with bone metastases and eight with multiple myeloma. Mean age was 58 years (range 36-83). The spinal segment involved was the cervical spine in five cases, the thoracic spine in 12 and the lumbar spine in 23. Vertebroplasty was done under fluoroscopy guidance after premedication and local anesthesia.

RESULTS

thirty-six patients (97.3%) reported a decrease in their pain 48 hours after the procedure; five of these patients (13.5%) were completely free of pain, 20 (55%) were significantly improved and 11 (30%) were moderately improved. One patient failed to respond. The clinical results were not correlated to the extent of vertebral body filling. Beneficial effects were increased or unchanged in 100% of cases after one month, 88.9% after three months and 75% after six months. Leakage of the cement outside the vertebral body occurred in 29 cases (72.5%), usually into the paraspinal soft tissues (n = 21,52.5%). Leakage was usually clinically silent and only two patients developed severe nerve root pain due to leakage into a neural foramen, with in both instances a favorable outcome after surgery.

CONCLUSION

Vertebro- plasty is simple and effective for the treatment of osteolytic metastases and multiple myeloma lesions, but should be performed only in centers with neurosurgical and/or orthopedic surgery units because of the possibility of severe complications.

[Giant cell tumors of the spine. Report of a case, literature review]

Giant cell tumors of bone are uncommon in the vertebrae above the sacrum. We report the case of a giant cell tumor of the third lumbar vertebra, revealed by lumbar and radicular pain. X ray, computed tomography and magnetic resonance imaging showed osteolysis of the body and vertebral arch of L3. Histologic evaluation gave a conclusion of a giant cell tumor, grade 2. Spondylectomy of L3 was performed using a combined approach (anterior and posterior) in two stages. The patient had a good functional result without recurrence at three years and six months. A review of the literature indicates that the radiological appearance is nonspecific but shows the extent of the tumor. Diagnosis can be based only on histological features. Radiotherapy could induce malignant transformation. Radical resection limits the risk of recurrence. Total spondylectomy is recommended for giant cell tumors when both the body and arch are involved.

Natural course of erosive arthropathy of the hand in patients undergoing hemodialysis

OBJECTIVE

To assess the radiographic features of erosive arthropathy of the hands occurring in patients undergoing hemodialysis, and its relationship with metabolic abnormalities.

PATIENTS AND DESIGN

A retrospective study of hand radiographs of 80 patients on maintenance hemodialysis was performed with the aim of detecting erosive arthropathy.

RESULTS AND CONCLUSIONS

Ten patients showed erosive arthropathy of the hands with a predilection for distal interphalangeal joints. The first joint abnormality was joint space narrowing with or without erosion. The mean duration of hemodialysis was 5 years (range 1-15 years). The development of arthropathy could not be related to a metabolic factor. The pathogenesis of arthropathy of the hands is possibly multifactorial, accounting for the disparate descriptions of the radiographic features in the literature.

Percutaneous vertebroplasty for osteolytic metastases and myeloma: effects of the percentage of lesion filling and the leakage of methyl methacrylate at clinical follow-up

PURPOSE

To determine whether the percentage of vertebral lesion filling and the leakage of methyl methacrylate have any clinical significance at follow-up.

MATERIALS AND METHODS

Forty percutaneous vertebroplasties were performed for metastases (30 cases) and myeloma (10 cases) in 37 patients. A computed tomographic scan was obtained 1-8 hours after methyl methacrylate injection and was used to assess the percentage of lesion filling by methyl methacrylate and the leakage of methyl methacrylate into the epidural tissues, neural foramina, intervertebral disks, venous plexus, and paravertebral tissue. The results were correlated with those obtained at clinical follow-up.

RESULTS

Partial or complete pain relief was sustained in 36 of 37 patients. Pain relief was not proportional to the percentage of lesion filling. Clinical improvement was maintained in most patients. The 15 epidural leaks, eight intradiskal leaks, and two venous leaks of methyl methacrylate had no clinical importance. Two of eight foraminal leaks produced nerve root compression that required decompressive surgery. One of 21 paravertebral leaks produced transitory femoral neuropathy.

CONCLUSION

Pain relief can occur despite insufficient lesion filling. In most patients, intradiskal and paravertebral leaks of cement had no clinical importance.

[Spinal tuberculosis. Study of clinical and radiological aspects from a series of 82 cases]

We present a retrospective study of 82 cases of spinal tuberculosis diagnosed over the last 30 years. An increasing incidence of this disease not related to HIV infection has become apparent since 1992. 24% of patients were born outside continental France. The intradermal reaction was negative in 10% of patients. Discovertebral lesions detected in 93% of patients was the most frequent radiological presentation. Spondylitis with osteolysis or bone sclerosis at single or multiple levels was seen in the others. Tuberculous lesion of the posterior arch was associated in 10% of patients. In most cases CT scan showed a fragmentary vertebral destruction which was characteristic of the disease. MRI revealed the precise extent of the lesions into the spinal canal. Morphologic features suggestive of the tuberculous nature of paravertebral abcesses could be demonstrated when slices were performed in the axial or coronal plan. Tuberculous involvement of the spine is still a frequent disease. The main clinical and radiological findings are presented.

Evaluation of destructive spondyloarthropathies in hemodialysis by computerized tomographic scan and magnetic resonance imaging

OBJECTIVE

The incidence of destructive spondyloarthropathies (SpA) in hemodialysis can reach 50% after 10 years of treatment. Few studies have analyzed the magnetic resonance (MR) appearance of destructive SpA and data are controversial. Our objective was to evaluate the computerized tomographic (CT) scan and MR appearance of destructive SpA in comparison to infectious spondylodiscitis.

METHODS

23 destructive SpA were observed in 11 patients who had undergone hemodialysis [mean duration of treatment 12 years (89-228 mo)]: 17 SpA of the cervical spine, one of the dorsal, and 5 of the lumbar spine. CT scans at all levels demonstrating narrowing and discovertebral erosions were performed without injection. MRI was performed with T1 and T2* weighted spin echo sequences (0.5T) without gadolinium injection. Radiographs were analyzed by 2 independent examiners. The data concerning MRI of infectious spondylodiscitis were based on a study of 57 personal cases and literature reports.

RESULTS

CT scan appearance was similar in all cases, especially showing multiple small well defined lucencies of the vertebral endplates. In 9 patients, MRI showed low signal intensity of the disk and the adjacent vertebral endplates on T1 and T2* sequences. In no case was discal or vertebral high signal intensity on T2* sequence noted. No periodontoidal pseudotumor was observed.

CONCLUSION

CT scans and MRI of destructive SpA, even nonspecific, are different from those observed in infectious spondylodiscitis, particularly due to the absence of discal and vertebral hypersignal on T2* sequences.

Abdominal aortic aneurysm. A rare cause of destructive lesions of the spine

A case of destructive vertebral and discal lesions in a patient with chronic, noninfected rupture of an abdominal aortic aneurysm is reported. The main rheumatic manifestations of abdominal aortic aneurysms are reviewed. Perianeurysmal inflammation may contribute to the development of destructive vertebral and discal lesions.