Use of MR imaging to assess results of chemotherapy for Ewing sarcoma

MR imaging was used to monitor the results of initial chemotherapy of primary Ewing sarcoma of bone. The signal intensities of the soft-tissue and marrow components of the tumor were evaluated on T2-weighted images obtained in 10 patients (nine with responsive tumors) at presentation and during and immediately after completion of two cycles of chemotherapy. MR evidence of marrow and soft-tissue involvement was seen in all tumors at presentation. After treatment, the bone-marrow component of the nine drug-sensitive tumors showed an increase in signal intensity that in eight cases became comparable to that of water. Changes in signal intensity of the soft-tissue component were variable, consisting of increases in two of the responsive lesions, no change in three, a decrease in two, and complete resolution of the soft-tissue mass in two. There was no increase in signal intensity of either the bone-marrow or the soft-tissue component of the single nonresponsive tumor. All of the responsive tumors showed advanced healing, and abundant bony sclerosis was apparent on CT. Bone-marrow examinations, performed in seven of the nine patients with responsive lesions, disclosed no evidence of tumor in four. Two patients had residual extramedullary tumor; the nonresponsive lesion contained sheets of tumor cells. The increase in marrow signal intensity on T2-weighted images was associated with replacement of marrow elements by a loose, hypocellular myxoid matrix containing modest amounts of collagen, consistent with response to chemotherapy and eradication of disease. Therefore, an increase in the T2-weighted signal intensity of the bone-marrow component of Ewing sarcoma of bone reflected a favorable response to chemotherapy. MR signal changes, however, were not predictive of resolution of malignant disease within adjacent soft tissue.     

Imaging of osteomyelitis in the mature skeleton

Diagnosis of acute osteomyelitis is often challenging but can be made by plain radiograph, bone scan, or MR imaging. This diagnosis may be more problematic in small bones, in diabetic or immunocompromised patients, those partially treated, post-traumatic, previous surgery, or with pre-existing marrow conditions and associated soft tissue infections. CT is the modality of choice for revealing sequestra and cortical erosions in chronic osteomyelitis. Nonenhanced and enhanced STIR or fat-saturated sequences are essential to reveal the marrow abnormality and its extension for diagnosis of subtle cases with neuropathic or other associated conditions. Combined radionuclide scintigraphy becomes necessary in complicated situations.     

Osteomyelitis in children: gadolinium-enhanced MR imaging.

Fifteen pediatric patients with biopsy- or culture-proved nonspinal osteomyelitis were studied with magnetic resonance (MR) imaging. Osteomyelitis was acute in seven patients, subacute in three, and chronic in five. Four patients had subperiosteal abscesses, one had a large associated soft-tissue abscess, and one had an intraosseous (Brodie) abscess. Areas of active inflammation had decreased marrow signal intensity on T1-weighted images, increased signal intensity on T2-weighted images, and enhancement on T1-weighted images obtained after gadopentetate dimeglumine administration (n = 10). Abscesses were rim enhancing (n = 3) or not (n = 2) with gadolinium-enhanced MR imaging. Nonenhancing areas presumably represented necrotic material. Gadolinium-enhanced MR imaging assisted in definition of the presence and extent of nonvascularized fluid collections within the bone and/or adjacent soft tissues and the extent of bone involvement in patients with chronic osteomyelitis. It also helped guide surgical debridement of intraosseous disease (n = 7) and open or percutaneous drainage of subperiosteal or soft-tissue fluid collections (n = 5).     

MR imaging of osteogenic and Ewing's sarcoma

Twenty patients with biopsy-proven osteogenic (11 cases) or Ewing's (nine cases) sarcoma were evaluated by MR imaging on a 0.15-T resistive unit to determine the value of MR in the diagnosis and treatment of these two neoplasms and to develop the best protocol for MR imaging. In all 20 cases, MR identified tumor spread into bone marrow, and it was superior to CT in five cases. Extension of tumor into the soft tissues adjacent to bone was shown better by MR than CT in six cases. Improved anatomic information from MR is the result of the ability to image in the axial, coronal, and sagittal planes. Compared with CT, MR identifies cortical disease but has inferior spatial resolution and defines calcium poorly. MR can be used to monitor tumor response to chemotherapy, and the relationship of tumor to adjacent vasculature can be determined without the use of contrast agents. Two pulse sequences are necessary for maximum display of disease, since, in general, tumor involvement of the bone marrow is best assessed on T1-weighted sequences, and tumor involvement of the soft tissue is best seen on T2-weighted sequences. Additional information about bone-marrow involvement, soft-tissue tumor extent, and the relationship of tumor to blood vessels makes MR a valuable adjunct to CT in the evaluation of these neoplasms.     

Detection of malignant bone tumors: MR imaging vs scintigraphy

One hundred six patients with a known or suspected diagnosis of bone cancer (11 patients with biopsy-proved primary tumors, 95 patients with metastatic disease) were evaluated with scintigraphy and MR imaging to determine the relative sensitivity of each technique in the detection of bone disease. MR imaging was performed at 0.5 T as part of the entry evaluation into Intramural Research Board protocols (30%), for evaluation of cord compression, or because of an equivocal scintigram. MR was performed with T1-weighted (e.g., 300-500/10-20 [TR/TE]), T2-weighted (e.g., 2000/80) spin-echo (SE), and a short-TI inversion recovery (STIR) pulse sequence. Scintigrams were performed with 99mTc-methylene diphosphonate. A retrospective analysis showed that in 30 (28%) of 106 patients, MR imaging performed over a limited region of interest revealed a focal abnormality consistent with tumor that was not observed on scintigraphy. Only one patient had an abnormality on scintigraphy, caused by a metastasis, that was not found on MR images. In 73 (69%) of the 106 patients, the results of MR imaging and scintigraphy were equivalent; in 41 cases results of both techniques were normal. A McNemar analysis of the discordant cases showed MR imaging to be more sensitive than scintigraphy was (p less than .001). Our results suggest that although MR imaging has a greater sensitivity in detecting focal disease, scintigraphy is still the most useful screening test for evaluating the entire skeleton. MR imaging should be reserved for clarification of scintigraphic findings when suspicion is high for tumor.     

Staging of neuroblastoma at imaging: report of the radiology diagnostic oncology group

PURPOSE: To compare the accuracies of computed tomography (CT), magnetic resonance (MR) imaging, and bone scintigraphy in staging disease in patients with neuroblastoma. MATERIALS AND METHODS: Ninety-six children with newly diagnosed neuroblastoma were enrolled in a multicenter prospective cohort study. CT, MR, and bone scintigraphy were used to evaluate tumor stage. Sensitivity and specificity values and receiver operating characteristic (ROC) curve analyses were used to compare the accuracy of CT, MR, and scintigraphy for tumor staging. RESULTS: Eighty-eight patients were eligible for staging analysis, and 45 patients who underwent surgery at initial diagnosis were eligible for analysis of local tumor extent. CT and MR had sensitivities of 43% and 83%, respectively (P <.01), and specificities of 97% and 88%, respectively (P >.05), for detection of stage 4 disease. Areas under the ROC curves for CT and MR were 0.81 and 0.85, respectively (P =.06); that for scintigraphy was 0.83. Addition of scintigraphy to both CT and MR increased the areas under the ROC curves to 0.90 and 0.88, respectively. Accuracy of CT and MR for staging disease confined to the chest or abdomen (stages 1, 2, and 3) was poor. CONCLUSION: MR alone and CT and MR combined with bone scintigraphy enable the accurate detection of stage 4 disease. Both CT and MR perform poorly for local tumor staging.     

Utility of 99mTc-labelled antimicrobial peptide ubiquicidin (29-41) in the diagnosis of diabetic foot infection

Purpose

Detection of osteomyelitis beneath a diabetic foot ulcer is imperative for proper management; however, accurate and noninvasive diagnosis of osteomyelitis remains a challenge. Ubiquicidin 29-41 (UBI 29-41) is a synthetic antimicrobial peptide fragment reported to be highly infection-specific. ^99mTc-UBI 29-41 has recently been reported to be a promising radiotracer for infection imaging. The aim of this prospective study was to evaluate the utility of ^99mTc-UBI 29-41 scintigraphy in diabetic patients with suspected osteomyelitis of the foot.

Methods

Included in the study were 65 patients with type 2 diabetes mellitus and foot ulcer and with clinical suspicion of osteomyelitis . Each patient had a three-phase bone scan and a ^99mTc-UBI scan at 30 and 60 min after injection. The scan was considered to be consistent with osteomyelitis when the ^99mTc-UBI 29-41 uptake was concordant with the ^99mTc-MDP uptake. It was considered negative for osteomyelitis if there was no uptake of ^99mTc-UBI 29-41 or if ^99mTc-UBI 29-41 accumulated in an area not concordant with the abnormal uptake of ^99mTc-MDP on the bone scan. In the latter case a diagnosis of soft-tissue infection was made. Bone infection was confirmed by bone biopsy/culture and by clinical and radiological follow-up.

Results

Final analysis was done in 55 patients. Osteomyelitis was confirmed in 37 patients, and 18 patients were free of bone infection. ^99mTc-UBI 29-41 was positive in all 37 patients and with the bone scan as the reference for the bone identified all osteomyelitic foci (68 in total). ^99mTc-UBI 29-41 was negative for osteomyelitis in all 18 patients, and 17 of these patients were diagnosed with soft-tissue infection (^99mTc-UBI 29-41 accumulation without concordant abnormal uptake on bone scintigraphy). The sensitivity, specificity and accuracy of ^99mTc-UBI 29-41 scan in combination with three-phase bone scan for the diagnosis of osteomyelitis in diabetic foot was 100 %. Accuracy for soft-tissue infection was also 100 %. Maximum accumulation of the ^99mTc-UBI 29-41 with maximum target to background activity was observed in the infectious foci at 30 min after injection.

Conclusion

Tc-UBI 29-41 may be a useful agent for the accurate diagnosis of bone infection in diabetic foot because of the high accuracy demonstrated in this pilot study. It was able to differentiate between bone and soft-tissue involvement effectively in combination with a bone scan.     

MR imaging of infectious spondylitis

MR images of 14 patients with pyogenic and three patients with tuberculous infectious spondylitis were studied to develop criteria for diagnosis. T1-weighted scans, 800/20 (TR/TE), were obtained in 17 patients and T2-weighted scans, greater than 2000/30,80, were obtained in 14. In seven patients, T2*-weighted scans (gradient-recalled acquisition into steady state, 25/15/5-7 degrees [TR/TE/flip angle]) and short-T1 inversion-recovery scans (STIR), 1400/150/40 (TR/TI/TE), as well as fat and water images (using a suppression technique), were obtained. Unenhanced and gadopentetate-dimeglumine-enhanced scans were obtained in four patients. In all but two patients with pyogenic infectious spondylitis, the T1-weighted sagittal scan showed characteristic findings: narrowed disk space, low signal intensity in the marrow of at least two adjacent vertebrae, subligamentous or epidural soft-tissue masses, and erosion of cortical bone. In one patient the T1-weighted scan was normal and abnormalities could be detected only on the T2-weighted scan. The remaining patient had abnormal marrow signal on the T1-weighted scan but only in one vertebral body. On T2-weighted images the major findings were a narrowed disk space with variable signal changes, abnormal high signal in marrow of at least two adjacent vertebrae, high-signal subligamentous or epidural masses, and cortical bone erosion. The findings in the three patients with tuberculous spondylitis included areas of increased and decreased signal intensity in vertebrae on T1-weighted images. Disk spaces were relatively spared given the extent of disease. Extraosseous soft-tissue components could be large. Bone erosion was best seen on the first echo of a T2-weighted sequence and on a water image; the latter was most reliable since it had no chemical-shift artifact. The use of gadopentetate dimeglumine could obscure or clarify MR findings, depending on the situation. T1- and T2-weighted MR images should be obtained for assessment of infectious spondylitis. STIR scans are particularly helpful. Fat images can be useful in subtle presentations, since they are very sensitive to marrow replacement, and gadopentetate dimeglumine may be helpful for epidural delineation of disease.     

Failure of MR imaging to detect reflex sympathetic dystrophy of the extremities

Reflex sympathetic dystrophy of the extremities is a disease with a wide spectrum of clinical manifestations. It is characterized by pain, hyperthermia, and cutaneous changes and has been linked to an abnormality of regional blood flow. The disease is associated with previous injury or trauma including surgery, but also has been found in association with myocardial infarctions and tumors. The final diagnosis can be made only on the basis of the clinical course, which is characterized either by regression without sequel or the appearance of aponeurotic and tendinous retractions including bony sclerosis in the affected region occurring over many months to years. The literature and our own results show that MR imaging has high sensitivity for diagnosing transient osteoporosis of the hip, which is generally thought to be a form of reflex sympathetic dystrophy. Therefore we investigated the usefulness of MR imaging for diagnosing sympathetic dystrophy of the extremities. Twenty-five patients underwent T1- and T2-weighted MR imaging of the affected body region. They were selected on the basis of the initial clinical findings and positive findings on scintigraphy, which is known to be a sensitive, but not very specific, imaging method for sympathetic dystrophy. The final diagnosis was established on the basis of the clinical course in 17 of the 25 patients. In 10 of these, findings on MR images were completely normal, in six the MR images showed only nonspecific soft-tissue changes or bone marrow sclerosis, and in one patient they showed changes in bone marrow signal. Of the remaining eight patients without a final diagnosis of sympathetic dystrophy, MR showed soft-tissue or bone marrow alterations in six. MR imaging appears to be of little value in establishing the diagnosis of sympathetic dystrophy, but it may improve diagnostic specificity when used in conjunction with scintigraphy.     

Infections of the musculoskeletal system: high-field-strength MR imaging

Twenty-two patients with clinical findings consistent with osteomyelitis, soft-tissue infection, or both were studied with magnetic resonance (MR) imaging at 1.5 T. Another 15 patients with joint effusion but no clinical or laboratory signs of infection served as controls. Soft-tissue abscesses, osteomyelitis, joint and tendon sheath effusion, and cellulitis were well depicted on MR imaging, allowing the correct diagnosis of presence and extent of infection in all but two cases. MR imaging was as sensitive as technetium-99m methylene diphosphonate bone scintigraphy in demonstrating osteomyelitis and was more specific and more sensitive than other scintigraphic techniques in demonstrating soft-tissue infections, primarily because of its superior spatial resolution. Computed tomography, performed in seven cases, was as accurate as MR imaging in demonstrating bone and soft-tissue infections. Infected and noninfected synovial effusions had the same signal intensity, but associated findings such as soft-tissue fluid collections or osteomyelitis made the distinction possible.     

Segmental patterns of avascular necrosis of the femoral heads: early detection with MR imaging

Thirty-two patients (64 hips) in whom avascular necrosis (AVN) of the femoral heads was highly suspected clinically were studied by magnetic resonance (MR) imaging, radionuclide bone scintigraphy, and conventional radiography. MR studies were positive for AVN in 37 hips, compared with 30 positive scintigraphic studies. In all cases in which scintigraphy and radiography were positive, MR imaging demonstrated decreased signal from the affected femoral heads, indicative of bone marrow disease. Imaging results were confirmed by biopsy or subsequent imaging appearances. In patients with negative initial scintigraphic and radiographic studies, the MR imaging criterion for a positive study was a moderately decreased bone marrow signal displaying segmental patterns within an otherwise normal-appearing femoral head on relatively T1-weighted images. In this series of high-risk patients, radionuclide scintigraphy had a sensitivity of 81%, compared with 100% for MR imaging. MR imaging should be the imaging modality of choice for early evaluation of bone marrow changes indicative of AVN.     

MR features of tuberculous osteomyelitis

OBJECTIVE: To describe the MR imaging features of tuberculous osteomyelitis. DESIGN AND PATIENTS: MR imaging features of 11 patients (14-65 years) with proven extra-spinal tuberculous osteomyelitis were reviewed. Osseous and adjacent soft-tissue changes were analyzed. RESULTS: On the basis of the signal intensity characteristics compared with the normal marrow fat, two kinds of lesions were observed: (a) predominantly intermediate to low signal intensity lesions on T2-weighted images with low signal intensity on T1-weighted images, and (b) lesions which had a discrete peripheral zone of marginally higher signal intensity than the center on T1-weighted images and surrounding edema and lower signal intensity than the fatty bone marrow with variable signal intensity on T2-weighted images. Soft-tissue abscesses and marrow edema were each noted in eight cases. Soft-tissue edema was noted in most cases. CONCLUSION: An osseous lesion with intermediate to low signal intensity on T2-weighted images and associated soft-tissue abscess may be suggestive of tuberculous osteomyelitis. Lesions with a rim of mildly increased signal intensity on T1-weighted images, a non-specific indicator of an infective process, may also be seen.     

Whole-body bone marrow MRI in patients with metastatic disease to the skeletal system

PURPOSE: The purpose of this study was to evaluate the diagnostic potential of a whole-body bone marrow MR protocol in the detection of bone metastases. METHOD: Whole-body bone marrow MRI was performed in 18 patients with known malignant tumors and suspected bone metastases. The imaging protocol consisted of fast T1-weighted and STIR sequences applied in different anatomical positions covering the whole skeleton. MRI findings indicating bone metastases were compared with findings from bone scintigraphy. Metastatic lesions were confirmed by follow-up MR examinations, bone scintigraphy, radiography, or CT. RESULTS: A total number of 216 lesions were detected with MRI in comparison with 159 lesions detected with bone scintigraphy. Follow-up examinations confirmed 105 lesions. MRI detected 96 (91.4%) of the confirmed lesions, whereas bone scintigraphy detected 89 (84.8%). The entire examination, including patient positioning and changing of imaging coils, required 45 min of room time. CONCLUSION: Whole-body bone marrow MRI as used in this study is an effective method for evaluating the entire skeletal system in patients with suspected metastatic disease.     

Staging of spinal metastasis using special techniques of magnetic resonance imaging

The diagnosis of spine metastasis is a problem of great interest which leaves many questions unanswered. In this field MR imaging plays a fundamental role, as the only technique able to directly demonstrate the changes in bone marrow tissue, bound to tumoral activity. The introduction of gradient-echo (GE) sequences has helped reduce examination time. Moreover, with the accurate choice of pulse-sequence parameters (TR, TE, flip angle) additional information is acquired which is not yielded by conventional spin-echo (SE) sequences. Our study was aimed at evaluating MR sensitivity in the different stages of bone metastatic evolution. The comparative adequacy was evaluated of combined bone scintigraphy and conventional radiology versus MR imaging in 62 patients with vertebral metastases. Time interval between bone scan and/or radiological study and MR exam ranged from 10 days to 8 months. SE and GE T1-weighted images, and SE and GE T2-weighted images on the sagittal plane were employed, and axial images; coronal images were rarely acquired. Metastases were demonstrated by MR imaging at 122 vertebral levels, versus 88 true positives of combined scintigraphy and conventional radiology. Scintigraphic false-positives were observed at 15 vertebral levels, versus 9 with radiography. GE sequences were superior to SE ones in detecting vertebral morphologic lesions and bone marrow involvement thanks to their improved resolution and sensitivity. Moreover, GE sequences demonstrated tumoral bone marrow spread and persistent tumoral activity in the follow-up of spine metastases. Our results point to GE sequences as those of choice because of their higher resolution and sensitivity, which also allow response to treatment to be evaluated.     

Chronic osteomyelitis: diagnosis with tech netium-99m-d,l-hexamethylpropylene amine oxime labelled leucocytes

To evaluate the diagnostic value of technetium-99md,l-hexamethylpropylene amine oxime (HMPAO) labelled leucocytes in combination with a^99mTc-methylene diphosphonate (MDP) bone scan in the detection of chronic osteomyelitis, we retrospectively reviewed 55 patients. Prior to the^99mTc-d,I-HMPAO labelled leucocyte scan, all patients underwent a^99mTc-MDP bone scan. The correct diagnosis was confirmed by long-term clinical follow-up (n=29) or by bacteriological cultures (n=26). We found an overall sensitivity of 94%, a specificity of 91% and an accuracy of 92% for^99mTc-d,l-HMPAO labelled leucocyte scintigraphy in the diagnosis of chronic osteomyelitis. When the patients were divided into three groups according to the location of the infection, our study results showed a sensitivity and specificity for the central location (containing active bone marrow) of 94% and 100% respectively; for the peripheral location (hands and feet) both parameters were 100%, and for the middle location (all sites between the central and the peripheral location) the values were 92% and 81% respectively. Specificity and accuracy were significantly lower in the middle location than in the central and peripheral locations. The results of our study confirm that a^99mTc-d,l-HMPAO labelled leucocyte scan in combination with an^99mTc-MDP bone scan is a reliable way to diagnose chronic osteomyelitis, except for vertebral osteomyelitis.     

Effect of soft-tissue pathology on detection of pedal osteomyelitis in diabetics

Three-phase bone scans were performed on 30 diabetic patients suspected of having acute pedal osteomyelitis; 23 also had a pedal ulcer, seven had coexisting cellulitis, and 14 had diminished pedal pulses. Fifteen patients were receiving antibiotics at the time of the scan. A tissue diagnosis was available in 18 patients and 12 had no clinical evidence of infection on follow-up. Focal arterial hyperemia combined with focally increased activity on blood-pool and delayed (2-3 hr) scans were interpreted as acute osteomyelitis. Scans showing venous hyperemia were interpreted as soft-tissue pathology without acute osteomyelitis. Companion radiographs were reviewed independently. The sensitivity and specificity of the scans for osteomyelitis were 0.94 and 0.79, respectively, while radiographic sensitivity was 0.93 and specificity was 0.50. The presence of soft-tissue ulcers or cellulitis, peripheral vascular disease, or recent antibiotic therapy had no significant adverse effect on the accuracy of the three-phase scan in diagnosing osteomyelitis.     

Imaging of tumoral calcinosis: new observations

Five patients with tumoral calcinosis were evaluated with radiography, bone scintigraphy, computed tomography (CT), and magnetic resonance (MR) imaging. The arthropathy of calcium pyrophosphate dihydrate deposition disease was seen in two of the patients and pseudoxanthoma elasticum-like syndrome in three. Identification of calcific particular masses on radiographs is characteristic of tumoral calcinosis. Marrow lesions could be identified as patchy areas of calcification (calcific myelitis) in long bones and the calvarium. Bone scintigraphy appears to be the best modality for detection of the masses and marrow lesions and for monitoring therapy. At CT the masses demonstrated a varied appearance, from small and solid to large and cystic. The marrow abnormality appears as an area of increased attenuation and spotty calcification that in the skull may be associated with dural and vascular calcifications. MR imaging of the particular masses was remarkable in that the masses displayed high signal intensity on T2-weighted images despite a large calcific component. Marrow lesions also showed increased signal intensity on T2-weighted images. When calcified particular masses are present the diagnosis is rarely in question. The diagnosis may be overlooked, however, when calcific myelitis is the only manifestation.     

MR imaging characteristics in primary lymphoma of bone with emphasis on non-aggressive appearance

Purpose To assess the heterogeneity of magnetic resonance (MR) imaging characteristics in primary lymphoma of bone (PLB), in particular the non-aggressive appearance. Subjects and methods In a retrospective study, MR imaging features were analyzed in 29 patients with histologically proven PLB. The following parameters were evaluated: tumor size, bone marrow and extension into soft tissues, signal characteristics of bone marrow and soft-tissue components, including enhancement, and involvement of cortical bone (complete disruption, focal destruction, permeative destruction and cortical thickening). Results PLB presented with extension into the soft tissue in 22 (76%) of 29 patients, was only subtle in three of these 22 patients, and was absent in seven patients. Signal intensity (SI) of the soft-tissue part was most frequently homogeneously isointense with muscle on T1-weighted images (90%) and high on T2-weighted images (91%). Enhancement was predominantly homogeneous and diffuse (82%). In 93% of patients cortical bone appeared abnormal: among those patients complete cortical disruption was seen in 28%, with extension into soft tissues in all but one patient; a permeative pattern of destruction was present in 52% of patients, 66% of these had an associated soft-tissue mass. Two patients with normal-appearing cortical bone had no extension into soft tissues. In two patients focal cortical destruction was noticed; in one patient cortical bone was homogeneously thickened, and in one patient PLB was selectively localized within the cortical bone. SI of the bone marrow tumor component was more frequently heterogeneous (in 54%), compared with the soft-tissue component, being high on T2-weighted images in 89%, intermediate in 7% and low in 4%. Similarly, enhancement was heterogeneous in 59%. Conclusion The MR imaging appearance of PLB is variable. In 31% of PLB patients, the tumor was intra-osseous, with linear cortical signal abnormalities or even normal-appearing or thickened cortical bone without soft-tissue mass, and, as such, PLB may not infrequently look non-aggressive on MR imaging.     

Anterolateral ankle impingement: mr arthrographic assessment of the anterolateral recess

PURPOSE: To determine the accuracy of magnetic resonance (MR) arthrography in assessing the anterolateral recess of the ankle. MATERIALS AND METHODS: Thirty-two patients with chronic ankle pain prospectively underwent gadolinium-enhanced MR arthrography of the tibiotalar joint. All underwent clinical examination and were included if anterolateral impingement (n = 13) or a control condition (n = 19; suspected osteochondral defect, intraarticular bodies, instability, osteoarthritis) was diagnosed. MR imaging included transverse and coronal T1-weighted and sagittal T2-weighted imaging sequences. Images were prospectively analyzed by two readers blinded to the clinical diagnosis. The anterolateral gutter contour was assessed. MR arthrographic findings were correlated with subsequent arthroscopic appearances. RESULTS: MR arthrographic assessment of the anterolateral soft tissues had an accuracy of 97%, sensitivity of 96%, specificity of 100%, negative predictive value of 89%, and positive predictive value of 100%. Accuracy was 100% with clinical anterolateral impingement, with an arthroscopically confirmed abnormality in 12 cases and a normal appearance in one. Anterolateral soft-tissue thickening was identified at MR arthrography in 11 control cases, with arthroscopic confirmation in all. The remaining cases had normal appearances, with an arthroscopic soft-tissue abnormality in one case and a normal appearance in seven. CONCLUSION: MR arthrography of the tibiotalar joint is accurate in assessing the anterolateral recess of the ankle.     

Trans-sphenoidal spread of rhinopharyngeal neoplasms. Correlations between computerized tomography and magnetic resonance

In 1957 Teoh observed, in an autopsic series of 31 patients with nasopharyngeal carcinoma, 3 cases of neoplastic spread through the marrow spaces of the base of the skull, without macroscopic bone alterations. In order to demonstrate in vivo this kind of neoplastic spread, CT and MR examinations of 35 patients with nasopharyngeal carcinoma were reviewed. In 3/26 cases the invasion of the marrow spaces of the clivus was demonstrated. In these cases CT showed only minimal alterations in spongiosa and cortices of the clivus, associated with intracranial soft-tissue tumoral components. MR imaging demonstrated, with great accuracy, the replacement of bone marrow in the clivus by neoplastic tissue of intermediate signal intensity on T1-weighted images. Tumor tissue was characterized by high signal intensity on T2-weighted images. The authors stress the greater utility of MR imaging in evaluating the permeative involvement of the base of the skull.