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Malignant cartilaginous tumors (chondrosarcomas) are, with a relative frequency of 20%, the second most common malignant tumors of bone after osteosarcoma. The diagnosis of chondrosarcoma can usually be made confidently based on combination of clinical information, radiographs, Gd-enhanced MR imaging, and histologic examination of a biopsy sample. The combination of these parameters is important because accuracy of histologic diagnosis is adversely affected by unrepresentative sampling of these usually large tumors. The prognosis of patients with chondrosarcoma becomes poorer with more axial location, higher histologic grade, larger tumor size and inadequate resection. By careful analysis of radiographs and Gd-enhanced MR imaging the radiologist has the ability to improve the management of patients with chondrosarcoma.

Objective: To identify an optimal pulse sequence for in vitro imaging of hyaline cartilage at 0.5 T., Materials and Methods: Twelve holes of varying diameter and depth were drilled in the cartilage of two pig knees. These were submerged in saline and scanned with a 0.5-T MR system. Sixteen T1-weighted gradient echo (GE), two T2-weighted GE, and 16 fast spin echo sequences were used, by varying repetition time (TR), echo time (TE), flip angle (FA), echo train length, profile order, and by use of fat saturation. Contrast-to-noise ratios (CNR) of cartilage versus saline solution and cartilage versus subchondral bone were measured. Cartilaginous lesions were evaluated separately by three independent observers. Interobserver variability and correlation between the quantitative and qualitative analyses were calculated., Results: The mean CNRs of two specimens of cartilage versus saline solution ranged from 6.3 (+/- 2.1) to 27.7 (+/- 2.5), and those of cartilage versus subchondral bone from 0.3 (+/- 0.2) to 22.5 (+/- 1.4). The highest CNR was obtained with a T1-weighted spoiled 3D-GE technique (TR 65 ms, TE 11.5 ms, FA 45 degrees). The number of lesions observed per sequence varied from 35 to 69. Observer agreement was fair to good. The T1-weighted spoiled GE sequences with a TR of 65 ms, TE of 11.5 ms and FA of 30 degrees and 45 degrees were significantly superior to the other 34 sequences in the qualitative analysis., Conclusion: T1-weighted spoiled 3D-GE sequences with a TR of 65 ms, a TE of 11.5 ms, and a FA of 30-45 degrees were found to be optimal for in vitro imaging of cartilage at 0.5T.

Objective: To identify specific features of chondroblastic osteosarcoma on gadopentetate dimeglumine (Gd)-enhanced magnetic resonance (MR) imaging., Design and Patients: Nine patients with chondroblastic osteosarcoma and a control group of 20 patients with conventional central osteosarcoma were included in this study. The histopathological findings of the surgical specimens were compared with enhancement patterns on static Gd-enhanced MR images., Results: In chondroblastic osteosarcoma septonodular and peripheral rim enhancement represented tumour with a pure chondroid matrix. Non-enhancing and heterogeneous enhancing areas represented tumour with both chondroid and osteoid matrix. In the tumours in the control group enhancement was predominantly heterogeneous but in one it was homogeneous. All these areas corresponded to necrotic or viable osteoid tumour tissue or fibrovascular tissue in areas of necrosis., Conclusion: Gd-enhanced MR imaging can assist in obtaining diagnostic biopsy material of chondroblastic osteosarcoma by identifying both osteoid- and chondroid-forming areas.

Magnetic resonance imaging, because of its exquisite soft tissue contrast, has dramatically improved the ability to preoperatively stage primary osseous and soft tissue neoplasms. This technique also has allowed the monitoring of the effects of chemotherapy and the screening for recurrence of neoplasms. The role of magnetic resonance imaging in the preoperative evaluation of the patient with a suspected primary osseous or soft tissue neoplasm is outlined, instances where magnetic resonance imaging potentially may make a specific diagnosis are outlined, the importance of gadolinium enhancement as an adjunct to native magnetic resonance imaging is stressed, and an algorithm for followup of patients after chemotherapy or definitive surgical treatment is presented. In all cases, the magnetic resonance images should be correlated with the plain film, which is still an important aspect of the diagnosis of osseous lesions.

Diagnostic imaging is pivotal in the initial detection, characterization, staging and post-treatment follow-up of patients with high-grade osteogenic and Ewing's sarcoma. In the present review article, conventional and new imaging modalities are discussed with regard to the monitoring of the effect of neoadjuvant chemotherapy in such patients. Presurgical monitoring of response to chemotherapy may have an impact on modification of neoadjuvant treatment protocols, on patient selection for the performance and timing of limb-salvage surgery and on planning of radiation therapy (in non-operated Ewing's sarcomas) and selection of postoperative chemotherapy regimens. Dynamic contrast-enhanced MR imaging, as part of a routine MR protocol, assists in the detection of the most viable parts of the tumour and serves as an initial standard for follow-up of the metabolic activity of the tumour during and after chemotherapy, both in small intraosseous tumours and in tumours with an associated soft tissue mass. In combination with selected morphological features, dynamic imaging parameters are therefore advocated for monitoring the effect of neoadjuvant chemotherapy in patients with osteogenic and Ewing's sarcoma.

Objective: To analyse to what extent MR imaging based decisions were correct in determining the surgical procedure in patients with osteosarcoma of the distal femur., Design: We compared the findings on MR imaging that determined the surgical strategy with the actual surgical findings or histopathological specimen. We assessed to what extent MR images could be used to determine the surgical procedure in patients with osteosarcoma., Patients: Between 1985 and 1992, 34 patients with an osteosarcoma were treated. Two patients had a low-grade osteosarcoma. Thirty-two patients with a high-grade osteosarcoma of the distal femur (17 stage IIB, 15 stage III) were included in this study. Surgical options consisted of either limb salvage surgery or ablative surgery, which included the Van Nes-Borggreve rotationplasty. Limb salvage surgery consisted of extra-articular or transarticular resection, followed by reconstruction. Surgery was planned depending on the local extent of the tumour as depicted on the MR studies, coupled with data from the biopsy, age, patient compliance and histological grade. Follow-up was available in all patients. Nine of 17 patients graded as IIB were alive with an average follow-up of 68 months (range 46-109 months), of whom one has metastases. No local recurrence was encountered., Results: If no tumour involvement on MR imaging was found and this was used as a determining factor, this proved to be correct at subsequent analysis. We found that in eight of 11 cases, when MR images suggested a close relationship between tumour and nerve, an oncologically safe plane could be achieved during surgery. In three, a free plane could not be accomplished, as confirmed at histopathological examination. Hence, when nerve involvement was equivocal on MR imaging we found it valuable to reassess nerve involvement during surgery and reconsider limb salvage surgery. When the decisive factor was the vascular involvement and tumour extension was read as equivocal, it was possible to obtain a oncologically safe plane in six of 13 cases. When comprehensive tumour involvement of any structure was noted pre-operatively, it proved to be correct at histopathological examination, except for one case of assumed vascular involvement that proved to be free., Conclusions: If no tumour involvement of a structure was found on MR imaging and this was used as a determining factor, this proved to be correct. When nerve involvement was equivocal on MR imaging we found it valuable to reassess nerve involvement during surgery and reconsider limb salvage surgery. Extensive tumour involvement of any structure, as shown by MR imaging, could be used correctly as a decisive argument in planning a surgical procedure.

Objective: The purpose of this study was to evaluate clinical symptoms and radiographic features that allow radiologists to differentiate between enchondroma and central grade 1 chondrosarcoma. Such differentiation is important because of differences in management., Materials and Methods: Clinical symptoms and location and size of 35 enchondromas and 43 central grade 1 chondrosarcomas were analyzed. Radiographic features were assessed independently by three observers. The chi-square test and linear discriminant analysis were used to identify features with discriminating strength. Kappa values were calculated to validate the consistency of observations among observers. A consensus diagnosis made by histology and long-term follow-up was used as the standard., Results: No statistically significant correlation was found between clinical symptoms and the benign or malignant nature of the neoplasms. Grade 1 chondrosarcomas were more likely to be found in the axial skeleton and in flat bones. Also, chondrosarcomas were significantly larger than enchondromas (p < .001). Ill-defined margins and lobulated contours were the only morphologic features seen on radiographs that allowed significant discrimination (p = .004 and .009, respectively). An optimal combination of four radiographic features still left 72 of the 78 lesions with a 10-90% probability of malignancy, indicative of poor discriminating power. Kappa values generally showed poor to fair agreement., Conclusion: Location in the axial skeleton and size greater than 5 cm are the most reliable predictors of central grade 1 chondrosarcoma. Morphologic features seen on radiographs and clinical symptoms do not improve the ability to differentiate between enchondromas and central grade 1 chondrosarcomas.

MR imaging has had an unparalleled impact on the treatment of patients with musculoskeletal sarcoma. Basically, the high accuracy of local staging has made the introduction of reconstructive and limb salvage procedures instead of amputation of disarticulation available to the majority of patients with musculoskeletal sarcoma. Pre-operative work-up with MRI is not only more accurate, but also much faster and cheaper than the conventional work-up. Staging is the single most important reason for performing MR imaging in patients with musculoskeletal tumours. The impact of MR specificity is less dramatic but the benefit to the patient is an increased safety margin. When diagnostic errors with devastating consequences are made nowadays, it is usually because the proper protocol has not been followed. A patient with a potentially malignant, or equivocal, musculoskeletal mass deserves to have a combined radiographic-MRI examination prior to invasive procedures. MRI does not currently have a major impact on chemotherapy decisions and colour Doppler ultrasound has a higher accuracy than MRI. However, selected cases, i.e. intraosseous tumours, dynamic Gd-enhanced MRI, can replace colour Doppler ultrasound.

The objective of this study was to evaluate the appearance and the natural evolution of desmoid tumors on MR imaging, given histologic correlation. The MR images of 30 desmoids (20 primary and 10 recurrent) in 26 patients were scored for a multiplicity of morphological parameters, signal intensity (SI) on different pulse sequences, and behavior after contrast administration. Natural evolution was evaluated in 2 primary and 3 recurrent lesions, and correlated with evolution on histologic specimens. Desmoid tumors are mostly found in muscles of shoulder and hip girdle and are often fusiform with partially ill-defined margins. Rare subcutaneous desmoids have a more stellar morphology. Variable amounts of low-SI areas are present on all sequences. On T1-weighted images (T1-WI), most lesions are near homogeneous and isointense to muscle, whereas on T2-WI they are more heterogeneous with an overall SI equal to or slightly lower than fat. Histologic correlation reveals that SI on T2-WI cannot be explained solely by cellularity. After initial growth, spontaneous evolution of desmoids is characterized by shrinking and an increase in low-SI areas on T2-WI. While distal lesions shrink, the more recent lesions in asynchronous multicentric desmoids have a tendency to develop proximally in the same limb, and should not be confused with recurrences. Fast growth, extracompartmental spread, and bone involvement are often seen in recurrences. Follow-up MR imaging of desmoids indicates natural regression of desmoids and more aggressive behavior of recurrences, which may justify a more conservative therapeutic approach.

Purpose: To investigate the cost-effectiveness of diagnostic strategies involving spiral computed tomographic (CT) or conventional pulmonary angiography in the diagnosis of suspected pulmonary embolism., Materials and Methods: A model was created for analyzing cost-effectiveness on the basis of available literature data. Diagnostic algorithms consisting of combinations of perfusion and ventilation scintigraphy, ultrasound, D-dimer assay, conventional angiography, and spiral CT angiography were compared. Preference for strategies was determined on the basis of the mortality and cost per life saved., Results: For all realistic values of the pretest probability of pulmonary embolism and coexisting deep vein thrombosis and of the specificity of spiral CT angiography, all of the best strategies included spiral CT angiography. With an assumed sensitivity for spiral CT angiography of less than 85%, a conventional angiographic strategy yielded a lower mortality but did not yield superior cost-effectiveness., Conclusion: The use of spiral CT angiography is likely to reduce the mortality and improve cost-effectiveness in the diagnostic work-up of suspected pulmonary embolism.

Two men aged 17 and 23 years had a swelling on the foot which was neither an abscess nor a ganglion. Histological study revealed Ewing's sarcoma and synoviosarcoma, respectively. In both patients amputation under the knee was performed; nevertheless both developed metastases. In case of a swelling of the foot the possibility of malignancy has to be considered in order to shorten the diagnostic period. Consultation of the 'Commissie voor Beentumoren' may be desirable because of the low incidence and often difficult diagnostic process.

The purpose of this article is to review the basic principles and clinical applications of dynamic contrast-enhanced MRI in the musculoskeletal system. This method of physiologic imaging provides clinically useful information by depicting tissue vascularization and perfusion, capillary permeability, and composition of the interstitial space. Different imaging, evaluation, and postprocessing techniques are described. The most important applications in the musculoskeletal system are identification of areas of viable tumor for biopsy, tissue characterization, and monitoring of preoperative chemotherapy. Practical guidelines for performing a dynamic contrast-enhanced MR examination are proposed.

Objective: Comparison of clinically observed neurologic long tract signs in a heterogeneous group of patients with rheumatoid arthritis (RA), with morphologic abnormalities of the cervical spine as depicted on radiographs and magnetic resonance (MR) images., Design: The patients were prospectively assigned to one of three classes on the basis of their neurologic status. Lateral cervical spine radiographs and sagittal T1-weighted and gradient echo images were performed. The qualitative MR features evaluated were erosion of the dens and atlas, brain stem compression, subarachnoid space encroachment, pannus around the dens, appearance of the fat body caudal to the clivus, and the signal intensity of the pannus. The quantitative imaging parameters were the cervicomedullary angle and the distance of the dens to the line of McRae., Patients: Sixty-three consecutive patients with RA and subjective symptoms, especially neck or occipital pain, and/or clinical objective signs consistent with a compromised cervical cord were included in this study., Results and Conclusions: Damage documented with radiographs and MR imaging in patients with RA is often severe, even in those without neurologic signs (class 1). None of the abnormalities confined to the atlantoaxial level correlated significantly with neurologic classification. Subarachnoid space encroachment anywhere in the entire cervical spine did correlate significantly with neurologic classification.

Objective: The objective of this study was to assess the effectiveness of conventional radiography in predicting histopathologic response in patients with osteogenic sarcoma who were treated with preoperative chemotherapy., Design and Patients: The radiographs of 22 patients with an osteogenic sarcoma, taken before and after neoadjuvant chemotherapy, were reviewed. Tumour location, size, radiographic appearance, margination, cortical destruction and periosteal reaction were evaluated. The findings were correlated with the histopathologic response of the surgical specimen., Results: None of the findings proved to be of predictive value for the histopathologic response. Increase in tumour diameter and increase in ossification and/or calcification, which were seen in more than half of the patients, did not correlate with response., Conclusion: Conventional radiographs do not contribute to the identification of good or poor responders.

Purpose: To evaluate radiographically the history of the Mecron acetabular prosthesis., Material and Methods: The pelvic radiographs of 350 consecutive patients with a smooth threaded acetabular prosthesis type Mecron were retrospectively evaluated (follow-up 1 to 6 years, mean 4 years). A demarcation zone seen at the medial side of the prosthesis was graded from 0 (absent) to 3 (severe). Prostheses with grades 0 and 1 were considered stable and those with grade 3 with or without migration were presumed to be unstable., Results: At five years, 62 (62%) of the cups were unstable and only 23 (23%) were stable. The rate of migration was unacceptably high, and seen in 43 (43%) patients. Migration was only seen in prosthesis with a grade 3 demarcation., Conclusions: Demarcation visible on radiographs is an important sign of instability of the prosthesis. With the grading system it is possible to evaluate radiographically the history of the prosthesis.

Objective: This study analyzed the value of dynamic contrast-enhanced and subtraction MR images in detecting residual viable tumor before surgery, with emphasis on timing of enhancement, in patients with high-grade osteosarcoma and Ewing's sarcoma after neoadjuvant chemotherapy., Subjects and Methods: Twenty-one patients with proved osteosarcoma or Ewing's sarcoma were treated with neoadjuvant chemotherapy followed by surgery. After IV administration of gadopentetate dimeglumine, dynamic enhancement patterns on preoperative MR images were compared with corresponding areas on histologic sections of the resected specimens. On dynamic subtraction images obtained with high temporal resolution (1.5-3 sec), the interval between arrival of the bolus of contrast agent in an artery and start of tumoral enhancement was used to distinguish residual viable tumor. Early enhancing foci (interval artery-tumor < 6 sec) and late or nonenhancing areas seen on MR images were correlated with the histopathologic findings in these areas of the resected specimens., Results: Early and progressively enhancing structures seen on MR images corresponded to feeding arteries, physeal vessels, or residual viable tumor at specific preferential sites on corresponding histologic sections of the resected specimens. Tumor foci as small as 3-5 mm2 could be detected on dynamic MR images. Remnant viable tumor was often located subperiosteally and at the margins of the tumor. Occasionally, active periosteal reaction without presence of viable tumor contributed to early enhancement. Late and gradually enhancing or nonenhancing areas corresponded histopathologically to regions of chemotherapy-induced necrosis, mucomyxoid degeneration, or fibrosis. Alternatively, late or nonenhancing areas were associated with reactive changes such as edema, hemorrhage, or osteomyelitis or with tumor-related extracellular matrices such as abundant osteoid or chondroid. Viable tumor areas with scarce formation of matrix on microscopy, such as small cell osteosarcoma areas or Ewing's sarcoma, showed early enhancement with rapid washout of contrast agent on the dynamic MR images., Conclusion: Fast dynamic contrast-enhanced sequences are essential for identifying residual tumor before surgery. A short time interval of less than 6 sec between arterial enhancement and tumoral enhancement strongly correlates with presence of viable tumor. Both therapy-related alterations of tissue and tumor-related matrices must be considered when late or lack of enhancement is noted on dynamic MR images.

To improve visibility of the interosseous ligaments at magnetic resonance (MR) imaging of the wrist, the authors made and tested a device to apply ulnar and radial stress. In two men with small lunotriquetral (n = 1) and scapholunate (n = 1) ligament defects, depiction became evident only with stress deviation. Stress testing with this device increased the diagnostic accuracy of MR imaging for detection of these lesions.

Objective: The purpose of this study was to use color Doppler flow imaging to predict the response to preoperative chemotherapy in patients with Ewing's sarcoma or high-grade osteosarcomas early in treatment., Subjects and Methods: Color Doppler flow imaging was done in 31 patients before, during, and after chemotherapy. In each phase of treatment, semiquantitative changes in intratumoral blood flow, changes in maximum intratumoral Doppler shifts, and changes in resistive indexes of arteries feeding limbs that contained tumors relative to contralateral normal arteries were compared with the histopathologic response, as evaluated on the resected specimens., Results: Before chemotherapy, pathologic flow was found in the extraosseous component of all but two patients. Resistive indexes in arteries that fed tumors were significantly lower (p < .001) than the resistive indexes in the contralateral normal arteries. Histopathologic response could not be predicted on the basis of the initial measurements of Doppler shifts and resistive indexes taken before or after the first cycle of chemotherapy. Histopathologic response could be predicted after the second cycle of chemotherapy. After the second cycle of chemotherapy, the resistive index in the arteries that fed tumors increased in eight of nine good respondents but did not change or decreased in eight of nine poor respondents (p = .03). Lower intratumoral Doppler shifts were measured in six of 10 good respondents but also in five of 13 poor respondents (p = .07). After the full course of chemotherapy, persistent lower resistive indexes were measured in the arteries that fed tumors in all poor respondents but one. Intratumoral flow and Doppler shifts further decreased in all good respondents but one. Changes in Doppler shifts (p = .001) and resistive indexes (p < .001) were statistically significant between good and poor respondents, irrespective of the tumor type studied., Conclusion: Decreased or unaltered resistive index in the arteries that feed tumors in addition to persistent intratumoral flow and high-frequency Doppler shifts after two cycles of chemotherapy suggest poor histologic response to chemotherapy in osteosarcoma and Ewing's sarcoma. An increased resistive index after two cycles is indicative of good response.

The magnetic resonance (MR) changes after one cycle of chemotherapy were compared with the prechemotherapy studies in 39 patients with osteosarcoma, in order to identify MR changes which can be used to assess early response to chemotherapy. Measurements of total tumour volume, signal intensity, and tumour enhancement of the intra- and extraosseous tumour component were performed. Change in the amount of oedema was subjectively assessed. Changes observed were correlated with histopathological response. Changes in tumour volume and of the signal intensity of the extraosseous tumour component on T2-weighting were the only two parameters which correlated significantly (P < 0.05) with histopathological response. Increase of tumour volume is the most significant parameter and indicates poor response (sensitivity 89%, specificity 73%). Only one good responder showed increase of tumour volume. Decreased or stable tumour volume was observed in both good and poor responders. Increase of signal intensity was found exclusively in five poor responders (sensitivity 100%, specificity 23%). Decreased or stable signal intensity was observed in both good and poor responders. Changes in the amount of oedema and contrast enhancement could not predict response at an early stage. We conclude that increase of tumour volume and increase of T2 signal intensity of extraosseous tumour can be predictive for poor response. MR criteria are not helpful in the early identification of good responders.

Magnetic resonance (MR) imaging was performed in 26 patients with Ewing's sarcoma of bone preceding and following neoadjuvant chemotherapy, to assess tumour response non-invasively prior to surgery. T1- and T2-weighted spin echo images were obtained. Changes including intra- and extramedullary signal intensities, tumour demarcation, tumour volume and the appearance of residual extramedullary tumour were compared with histopathology of the resected specimens. Reduction of tumour volume was significantly higher in good responders. Other single parameters did not correlate with histologic tumour response. However, when several MR parameters summarized in a classification system were combined, a positive correlation with histopathologic response was found. A limited decrease of tumour volume (< 25%) and/or residual soft tissue mass following chemotherapy correlated with a poor response. An inhomogeneous, well-defined cuff of abnormal tissue encircling the bone and/or radiological disappearance of the soft tissue tumour component following chemotherapy correlated with good response. Twenty-three out of 26 patients were correctly classified by MR as good or poor responders. Minimal residual disease (< 10% of the entire tumour volume), observed histologically, could not be identified with MR imaging. Tumour volume reduction and residual extramedullary tumour, rather than changes of signal intensity, are major features for evaluating the response to chemotherapy in Ewing's sarcoma.

A 36 year old woman with a history of chronic renal failure secondary to acute glomerulonephritis sustained an injury to the tendon of the triceps brachii in her right arm. Magnetic resonance imaging showed an incomplete rupture of the tendon. The injury was successfully treated conservatively.

A uniform classification of response to chemotherapy is essential to allow comparison of local effect and ultimate prognosis between different therapy schedules. We define a histological grading system for assessment of the response to chemotherapy in Ewing's sarcoma, based on the amount and architectural pattern of residual histologically viable-appearing tumour, the preferential sites of minimal residual tumour and the amount of tumour necrosis. Twenty-six consecutive patients with a biopsy-proven Ewing's sarcoma were treated with chemotherapy prior to surgery. The effect of chemotherapy was evaluated microscopically on the specimens obtained after surgery. Response to chemotherapy was classified as minimal or no effect (< 10% tumour necrosis), moderate effect (solid areas of remnant viable tumour), minimal residual disease, and no evidence of disease (100% tumour necrosis or well-vascularized fibrous tissue). The subperiosteal area in particular and, less frequently, soft tissues and intramedullary compartment were identified as sites of predilection for persistence of microscopic viable tumour foci, frequently depicted as pseudo-rosettes in a characteristic scattered pattern. Although it is not well known whether morphological viability of these residual clusters in Ewing's sarcoma indicates biological viability, accurate preoperative local staging, with special attention to preferential sites of residual viable tumour, is essential. The proposed grading system can be used to standardize assessment of chemotherapy in trials, and may serve as a standard for non-invasive monitoring of preoperative chemotherapy with magnetic resonance imaging.

35 patients with a smooth, threaded acetabular Mecron type prosthesis were examined with the aid of a table top with wiremarkers and a fixed 30-degree wedge to allow for reproducible positioning. Under fluoroscopic control, pelvic and spot films were made. The inter- and intraobserver variability of anteversion and inclination angle measurements of the prostheses had a standard deviation of less than 1 degree. The method can be applied to other acetabular prostheses as well.

Purpose: To prospectively evaluate color Doppler flow imaging (CDFI) with spectral analysis versus dynamic gadolinium-enhanced magnetic resonance (MR) imaging and three-phase bone scintigraphy in monitoring the effect of chemotherapy on bone sarcomas., Materials and Methods: Seventeen osteosarcomas and five Ewing sarcomas were examined with these imaging techniques before and after chemotherapy. Results were compared with the histopathologic response., Results: Before chemotherapy, high systolic Doppler frequency shifts (DFSs) and/or low-impedance Doppler signals were found in all but one tumor. Resistive indexes (RIs) in tumor-feeding arteries were substantially lower than in contralateral normal arteries. After chemotherapy, DFSs disappeared in five of seven good respondents and remained substantial in all but one poor respondent. RIs increased substantially in all good respondents and decreased or showed minor changes only in all but one poor respondent., Conclusion: CDFI with spectral analysis has an advantage over the other two techniques in monitoring the efficacy of chemotherapy in bone sarcomas because of its superior accuracy, noninvasive nature, availability, and low cost.

Objective: Because the distinction between adenomas and nonadenomas of the adrenal gland is essential, we investigated which of the following parameters--size, CT attenuation values, MRI signal intensity ratios on T1- and T2-weighted sequences, calculated T2 relaxation times, or T2 relaxation time ratios--provides better discrimination., Materials and Methods: We compared these parameters in 44 adrenal masses of 37 patients by means of the Student t test and receiver operating characteristics (ROC) analyses., Results: Only size, CT attenuation values, and signal intensity ratios on T2-weighted MR images of adenomas showed a significant difference from those of nonadenomas. With use of ROC analysis, CT demonstrated a significantly larger area under the curve compared to size and T2 signal intensity ratios, indicating superior performance., Conclusion: We found attenuation values on non-contrast-enhanced CT to be the best method in discriminating adrenal adenomas from nonadenomas. Adrenal masses with CT attenuation values below 15 HU warrant no further investigations.

To evaluate the incidence, quantity, and presentation of intra- and extraosseous edema accompanying benign and malignant primary bone lesions, the magnetic resonance (MR) studies of 63 consecutive patients with histologically proven primary bone tumors were reviewed. MR scans were assessed for the presence and quantity of marrow and soft tissue edema and correlated with peroperative findings, resected specimens and follow-up data. The signal intensity and enhancement of tumor and edema prior to and after intravenous administration (if any) of gadolinium-labeled diethylene triamine pentaacetate (Gd-DTPA) was analyzed. Marrow edema was encountered adjacent to 8 of 39 malignant tumors and 14 of 24 benign lesions. Soft tissue edema was found accompanying 28 of 39 malignancies and 10 of 24 benign disorders. On unenhanced T1-weighted MR images tumor and edema were difficult to differentiate. Tumor inhomogeneity made this differentiation easier on T2-weighted sequences. In 36 patients the contrast medium Gd-DTPA was used. Edema was present in 27 of these patients and the respective enhancement of tumor and edema could be compared. Edema always enhanced homogeneously, and in most cases it enhanced to a similar degree as or more than tumor. Marrow and, more specifically, soft tissue edema is a frequent finding adjacent to primary bone tumors. The mere presence and quantity of marrow and soft tissue edema are unreliable indicators of the biologic potential of a lesion. Unenhanced MR scans cannot always differentiate between tumor and edema, but the administration of Gd-DTPA is of assistance in differentiating tumor from edema.(ABSTRACT TRUNCATED AT 250 WORDS)

To study the effect of chemotherapy on normal fat, skeletal muscle, and bone marrow, T1 and T2 relaxation times were measured in 15 patients with bone sarcoma before and after each cycle of preoperative chemotherapy. A section plane containing the tumor and if possible the nonaffected extremity was imaged with combined multiecho spin echo and inversion recovery pulse sequences. T1 and T2 relaxation times were calculated in the normal-appearing tissues. Although some variation was found in the values in the individual patient and between patients, no systematic changes of relaxation times of fat, muscle, or bone marrow occurred in the course of treatment. We conclude that the chemotherapy used in bone sarcoma has no effect on relaxation times of normal fat, muscle, and bone marrow, and that therefore these tissues may serve as a reference for the signal intensity of tumor.

Objective: Contrast enhancement with gadopentetate dimeglumine has been advocated to increase the efficacy of MR imaging for paragangliomas of the head and neck. However, contrast media are expensive, time-consuming to use, and involve minimal but not negligible risks. The purpose of this study was to determine if the use of contrast material is warranted in patients undergoing MR imaging for the diagnosis of paragangliomas of the head and neck., Materials and Methods: Unenhanced MR images were compared with images obtained after administration of gadopentetate dimeglumine in 23 healthy subjects and 37 patients who had a total of 71 tumors. Three combinations of sequences were reviewed independently and in a random order by four observers who had no clinical information. Combination A comprised enhanced and unenhanced T1-weighted sequences, combination B comprised unenhanced T1- and T2-weighted sequences, and combination C was a combination of all sequences. A four-point scale of certainty was used. CT, scintigraphic, angiographic, and surgicopathologic findings were used as the standard of reference. Results were subjected to alternative free-response receiver-operating-characteristic (AFROC) scoring and statistical analysis., Results: The mean areas under the AFROC curve for combinations A, B, and C were 0.761, 0.856, and 0.827, respectively. Mean sensitivity/specificity values after dichotomizing the scoring results were 0.73/0.94, 0.79/0.95, and 0.78/0.94 for combinations A, B, and C, respectively. The performance of combinations B and C did not differ markedly, but both combinations were significantly better than combination A. In a relatively large percentage (36%) of small postoperative tumor residues not detected on unenhanced images, however, gadopentetate dimeglumine allowed detection., Conclusion: The results of this study indicate that, in general, the use of gadopentetate dimeglumine is not necessary for the detection of head and neck paragangliomas. The addition of contrast-enhanced imaging does not increase the sensitivity or specificity compared with imaging without enhancement. Only when searching for small postoperative tumor residues is the addition of gadopentetate dimeglumine warranted.

Gadolinium-enhanced magnetic resonance (MR) images were correlated with histopathologic findings in patients with cartilaginous tumors. Short repetition time/echo time spin-echo MR images obtained before and after intravenous administration of gadopentetate dimeglumine in 34 patients were evaluated. Twenty-four of 27 low-grade chondrosarcomas showed septal enhancement. The enhancing curvilinear speta consisted of fibrovascular tissue. The nonehancing areas consisted of paucicellular hyaline cartilage, cystic mucoid tissue, and necrosis. This enhancement pattern and corresponding histopathologic findings were not seen in three benign osteochondromas or four high-grade chondrosarcomas. Inhomogeneous or homogeneous enhancement correlating with highly cellular areas at histopathologic analysis was seen in all high-grade chondrosarcomas. The three osteochondromas showed peripheral enhancement that correlated with fibrovascular tissue covering the non-enhancing cartilage cap. The authors conclude that septal enhancement on MR images after intravenous administration of gadopentetate dimeglumine improves tissue characterization of cartilaginous tumors and may assist in identifying low-grade chondrosarcoma.

This article focuses on major clinical and imaging features that are of practical interest in diagnosis and management of bone forming neoplasms. Current histologic classification of these tumors is emphasized. Data presented are based on files of 1400 patients who have osseous neoplasms.

In a patient presenting with a soft tissue tumor, radiographs are needed to visualize or exclude osseous involvement. Ultrasound can be used to visualize the lesion for cytologic biopsy. If cytology does not rule out sarcoma, magnetic resonance imaging is indicated to stage the lesion. As a rule staging studies other than MR imaging are not needed to evaluate the local situation. Usually MR imaging does not assist in suggesting a specific diagnosis. In certain instances, however, morphology or the presence of high signal intensity on T1, or low signal intensity on T2-weighted images increases specificity. Thick needle biopsy or open biopsy should be performed following MR imaging. This reduces sample errors and increases the accuracy of preoperative staging.

Fifty-seven patients undergoing chemotherapy for osteosarcoma underwent evaluation with magnetic resonance (MR) imaging to identify changes related to a good or poor response. Spin-echo MR images obtained after preoperative chemotherapy were compared with images obtained before treatment. Histopathologic examination of each resected specimen was used to quantify the response. An increase in tumor volume and increased or unchanged edema were predictive of a poor histopathologic response (predictive values, 85%-92%). Decreased or unchanged tumor volume and a decrease in edema were poor predictors of a good response (predictive values, 56%-62%). Improved tumor demarcation, an increase in the size of areas of low signal intensity, and a decrease in joint effusion occurred independently of histopathologic response in almost half of the patients. With a subjective interpretation of MR images, poor respondents can be identified if an increase in tumor volume or no decrease in the amount of edema is seen. Subjective criteria do not contribute to the identification of good respondents.

In order to analyse the normal signal intensity of the medullary space of the odontoid process (dens) relative to age, the craniovertebral junction of 33 asymptomatic volunteers in six age groups was examined by means of magnetic resonance imaging. To avoid partial-volume effects 3-mm slices were used in sagittal and axial planes. The signal intensities relative to cerebral white matter varied from 0.51 to 1.23 in the sagittal plane and 0.56 to 1.51 in the axial plane. The signal intensities relative to muscle varied from 0.76 to 2.40 in the sagittal plane and 0.96 to 2.30 in the axial plane. The signal intensities relative to fat varied from 0.22 to 0.62 in the sagittal plane and 0.23 to 0.68 in the axial plane. No correlation with age of the volunteers was found. The normal medulla of the dens may exhibit a low signal intensity on T1-weighted images irrespective of age.

The long deltopectoral approach promoted by Neer is the standard for performing a total shoulder arthroplasty. However, this exposure is inadequate for preparation and bone grafting of the glenoid cavity or repairing an associated large rotator cuff tear. In the anatomy laboratory we looked for an alternative approach to the glenohumeral joint which would accommodate these difficulties. Afterwards we used this approach in 7 of 13 patients in whom a Biomet Bio-modular shoulder arthroplasty was planned. The study is prospective with a 1-year follow-up of 12 cases.

The demonstration of tendon xanthomas is helpful in diagnosing heterozygous familial hypercholesterolemia, but in many patients lipid may accumulate without clinical abnormality being present. We investigated the possibility of detecting the lipid element with magnetic resonance (MR) imaging in seven patients with familial hypercholesterolemia and six controls. Although the mean relative signal intensities measured on long TR/TE spin echo sequences of the tendon were significantly higher in patients than in controls, the lack of such elevation does not rule out the presence of such lesions. In vitro measurements indicated that the signal intensity of triglycerides was quenched by cholesterolesters. The anatomic findings of MR imaging were compared with those of ultrasonography (US), showing excellent correlation in measurements between MR images and US [r(S) = 0.95 and 0.97 respectively]. MR imaging and US provide equal information on the anatomy of the Achilles tendon; as an abnormally increased signal intensity within the xanthoma on MRI was found in only a minority of our patients, the value of MRI in the demonstration of Achilles tendon xanthomas is limited when using conventional T1 and T2 spin echo sequences.

The findings of MR imaging in 3 patients with bone metastases from medulloblastoma are reported. The first patient showed focal lesions of low signal intensity on T1-weighted spin echo images at a time when bone scintigraphy was negative for metastases. This patient later developed extensive osteosclerotic lesions visible on plain films. The bone marrow of the second patient showed diffuse low signal intensity on T1-weighted images. After chemotherapy the signal intensity of the bone marrow increased which correlated with a return of normal hematopoietic tissue. A response to chemotherapy was also found on MR imaging and repeat bone marrow biopsies in a third patient. A consistent finding was a low signal intensity on pre-gadolinium images, but the pattern (focal or diffuse abnormal signal intensity) was different in each patient. To our knowledge, this is the first report on MR imaging findings in bone metastases from medulloblastoma.

Computed tomography, ultrasound, nuclear scintigraphy, and laboratory tests (lactic dehydrogenase, alkaline phosphatase, and 5-nucleotidase) were compared in 135 patients with gastro-intestinal carcinoma to define the most useful test to detect hepatic metastases. Thirty-six patients (26.7 per cent) had hepatic metastases at laparotomy. Sensitivities were low: 46.2 per cent for nuclear scintigraphy, 57.6 per cent for ultrasound, 67.7 per cent for computed tomography and 62.9 per cent for lactic dehydrogenase. Accuracies ranged from 62.9 (lactic dehydrogenase) to 77.6 per cent (nuclear scintigraphy). No significant differences were found. Accurate and efficient detection of hepatic metastases is hampered by relatively low sensitivity, specificity and accuracy of the conventional imaging tests and laboratory tests.

The conventional methods of CT scan (CT), ultrasound (US), scintigraphy (SC), and laboratory tests (LDH, AP, 5-Nt) were prospectively compared in 135 patients with gastrointestinal carcinoma to define the most useful test to detect hepatic metastases. Thirty-six patients (26.7%) had hepatic metastases at laparotomy. Sensitivities were low: 46% for SC, 58% for US, 68% for CT and 63% for LDH. Accuracies ranged from 62% (LDH) to 78% (SC). No significant differences were found. Accurate and efficient detection of hepatic metastases is hampered by the relatively low sensitivity, specificity and accuracy of conventional imaging and laboratory tests.

Differentiation between benign fibrous dysplasia and malignant adamantinoma of the tibia is challenging because of the impact the diagnosis has on the choice of treatment (none or extensive surgery). The histologic and pathologic similarities of the lesions and the controversial relationship between fibrous dysplasia, osteofibrous dysplasia, and adamantinoma complicate the matter. We found a large overlap of histologic features in lesions considered either fibrous dysplasia or osteofibrous dysplasia on the basis of the radiologic findings. The purpose of this study was to determine the value of the plain radiograph of the lower leg in combination with clinical findings to differentiate the benign from the malignant condition. The clinical symptoms, radiographs, and histologic slides of 46 patients with fibrous dysplasia and 22 with adamantinoma in the tibia were reviewed retrospectively. In only one of 12 patients with radiologic or histologic characteristics of osteofibrous dysplasia were both radiologic and histologic criteria for the diagnosis present. A linear discriminant analysis was performed on six clinical (age, spontaneous pain, pain after trauma, swelling only, pain and swelling, and bowing deformity) and 25 radiologic signs. Fibrous dysplasia and its variant osteofibrous dysplasia could be identified correctly in 87% (40 of 46 patients) and adamantinoma in 95% (21 of 22 patients) by using the patient's age and four radiologic signs. When results from the discriminant analysis of a randomized subgroup of patients (32) were used on the other subgroup (36 patients), fibrous dysplasia was correctly identified in 84% (21 of 25) and adamantinoma in 82% (nine of 11). Fibrous dysplasia is more prevalent than adamantinoma in a young patient, when radiographs show a ground-glass appearance and anterior bowing and when there is no multilayered periosteal reaction and moth-eaten destruction. When radiologic signs and the patient's age are combined, fibrous dysplasia and adamantinoma can be discriminated in a high percentage of patients.

The appearance of the pancreas in 17 adult patients with cystic fibrosis was evaluated with magnetic resonance (MR) imaging. The pancreas was abnormal in 15 patients. Three patterns were observed: (a) lobulated enlarged pancreas with complete replacement by fatty tissue (n = 9), (b) small atrophic pancreas with partial replacement by fat tissue (n = 5), and (c) diffuse atrophy of the pancreas without fatty replacement (n = 1). Replacement of the pancreas by fat tissue was seen on T1-weighted images with, characteristically, a very high signal intensity. The sensitivity of MR imaging in depicting pancreatic abnormality in cystic fibrosis is 94%, which is comparable to that of computed tomography.

Eighteen hips in 15 children showed persistent roentgenographic evidence of congenital acetabular residual dysplasia at four- to eight-year follow-up evaluations. The mean follow-up period was 5.8 years. These hips were subsequently evaluated by magnetic resonance (MR) imaging. MR imaging studies revealed thick unossified chondroepiphyseal cartilage of the acetabular roof adjoining the ilium in all hips. The cartilage in these hips counterbalanced the steep acetabular slope seen on roentgenograms. Initially these hips were regarded as candidates for an acetabular reconstruction, but 11 hips displayed sufficient cartilaginous acetabular coverage on MR images. MR imaging promotes more accurate selection of patients for acetabular reconstruction and aids in the choice of the most appropriate type of acetabular reconstruction.

In a double-blind, prospective study, the authors analyzed bone scintigrams and magnetic resonance (MR) images of the spine in 71 patients with histologically proved skeletal metastases. Bone scintigrams and MR images were separately reviewed by four independent observers. Bone scintigraphy permitted identification of 499 abnormal vertebrae and MR imaging, 818 abnormal vertebrae. MR imaging depicted additional abnormal vertebrae in 49 patients. The authors conclude that MR imaging is more sensitive than bone scintigraphy in detection of vertebral metastases.

In order to establish the reliability of the assessment of tumour stage and hence of resectability of carcinoma of the pancreatic head by ultrasonography (US) and computed tomography (CT) a retrospective analysis was performed on 41 patients. Both direct imaging techniques were very accurate in detecting non-resectable disease, 100 and 85% respectively, but were much less accurate in predicting resectable cancer, 18 and 15% respectively. False-resectable results were established in 58% of US examinations and 42% of CT examinations. As demonstrated in this study, predicting resectability of carcinoma of the pancreatic head with US and CT is an inadequate method of assessing tumour stage and should be complemented by other techniques to ensure a reliable result.