Ewing sarcoma versus osteomyelitis: differential diagnosis with magnetic resonance imaging.

OBJECTIVE: To find and evaluate characteristic magnetic resonance imaging (MRI) patterns for the differentiation between Ewing sarcoma and osteomyelitis. MATERIALS AND METHODS: We identified 28 consecutive patients referred to our department for MRI (1.5 T) of an unclear bone lesion with clinical symptoms suggestive of Ewing sarcoma or osteomyelitis. MRI scans were re-evaluated by two experienced radiologists, typical MR imaging features were documented and a diagnostic decision between Ewing sarcoma and osteomyelitis was made. Statistical significance of the association between MRI features and the biopsy-based diagnosis was assessed using Fisher's exact test. RESULTS: The most clear-cut pattern for determining the correct diagnosis was the presence of a sharp and defined margin of the bone lesion, which was found in all patients with Ewing sarcoma, but in none of the patients with osteomyelitis (P < 0.0001). Contrast enhancing soft tissue was present in all cases with Ewing sarcoma and absent in 4 patients with osteomyelitis (P = 0.0103). Cortical destruction was found in all patients with Ewing sarcoma, 4 patients with osteomyelitis did not present any cortical reaction (P = 0.0103). Cystic or necrotic areas were identified in 13 patients with Ewing sarcoma and in 1 patient with osteomyelitis (P = 0.004). Interobserver reliability was very good (kappa = 1) in Ewing sarcoma and moderate (kappa = 0.6) in patients with osteomyelitis. CONCLUSIONS: A sharp and defined margin, optimally visualized on T1-weighted images in comparison to short tau inversion recovery (STIR) images, is the most significant feature of Ewing sarcoma in differentiating from osteomyelitis.

Isolated right-sided varicocele as a salvage pathway for portal hypertension.

Retrograde blood flow can occur in the testicular veins and in the pampiniformis plexus in the absence of valves or if the valves are incompetent, resulting in tortuosity and dilatation of the veins. These abnormal alterations in the anatomy of the veins, termed varicoceles, are associated with infertility in the male. Most varicoceles occur on the left. We report the case of a rare isolated right-sided varicocele in a male evaluated for infertility in whom extensive work-up revealed venous anomalies and a spontaneous porto-systemic shunt. In such cases, standard approaches to infertility treatment are fruitless.

[Diffusion-weighted MRI--a new parameter for advanced rectal carcinoma?]. / Diffusionsgewichtete Magnetresonanztomographie--Ein neuer Prognoseparameter beim fortgeschrittenen Rektumkarzinom?

PURPOSE: To evaluate the predictive value of apparent diffusion coefficient (ADC) on therapy outcome of combined chemoradiation in patients with primary carcinoma of the rectum. MATERIALS AND METHOD: Prior to standardized, combined, neoadjuvant chemoradiation, 16 patients with primary carcinoma of the rectum (cT3) were examined with magnetic resonance imaging (MRI). Diffusion-weighted spin echo echo-planar images (SE-EPI) and contrast-enhanced T 1 -weighted spin echo (SE) images at 1.5 Tesla were obtained. The mean ADC of the tumor region was calculated and correlated with the therapy outcome substantiated by postsurgical histopathologic staging. RESULTS: Tumor down-staging (pT0-2) occurred in 9 patients (therapy responders) and no down-staging (pT3) in 7 patients (therapy non-responders). The mean ADC measured 0.476 +/- 0.114 x 10(-3) mm 2/s in the responder group and 0.703 +/- 0.085 x 10(-3) mm 2/s in the non-responder group. Comparison of the mean ADC between the groups reached statistical significance (p = 0.001). CONCLUSION: The mean ADC might be a new quantitative parameter to predict therapy outcome of combined preoperative chemoradiation in patients with primary carcinoma of the rectum.

Creatine kinase, myosin heavy chains and magnetic resonance imaging after eccentric exercise.

The aim of this study was to examine the relationship between myosin heavy chain (MHC) release as a specific marker of slow-twitch muscle fibre breakdown and magnetic resonance imaging (MRI) of skeletal muscle injury after eccentric exercise. The effects of a single series of 70 high-intensity eccentric contractions of the quadriceps femoris muscle group (single leg) on plasma concentrations of creatine kinase and MHC fragments were assessed in 10 young male sport education trainees before and 1 and 4 days after exercise. To visualize muscle injury, MRI of the loaded thigh was performed before and 4 days after the eccentric exercise. All participants recorded an increase (P < 0.05) in creatine kinase after exercise. In five participants, T2 signal intensity was unchanged post-exercise compared with pre-exercise and MHC plasma concentration was normal; however, they showed an increase (P < 0.05) in creatine kinase after exercise. For the remaining five participants, there was an increase in T2 signal intensity of the loaded vastus intermedius and vastus lateralis. These changes in MRI were accompanied by an increase in MHC plasma concentration (P< 0.01) as well as an increase in creatine kinase (P < 0.01). We suggest that changes in MRI T, signal intensity after muscle damage induced by eccentric exercise are closely related to damage to structurally bound contractile filaments of some muscle fibres. Additionally, MHC plasma release indicates that this damage affects not only fast-twitch fibres but also some slow-twitch fibres.

Tumor microcirculation evaluated by dynamic magnetic resonance imaging predicts therapy outcome for primary rectal carcinoma.

Contrast enhanced dynamic studies of malignant tumors performed by computed tomography or magnetic resonance imaging (MRI) are increasingly applied to characterize tumor microcirculation for the prediction of therapy outcome. The aim of our study was to correlate perfusion index (PI) values determined in primary rectal carcinoma before chemoradiation with therapy outcome. In 17 patients with clinically staged T3 primary rectal carcinoma, dynamic MRI was performed before the onset of therapy using an ultrafast T1-mapping sequence. On the basis of the acquired data sets, PI values were calculated on a pixel-by-pixel basis. To characterize the heterogeneity of tumor microcirculation, relative cumulative frequency histograms of PI values within the tumors were computed. Subsequent resection of the tumors allowed correlating PI with histopathological classification. In 12 of 17 patients, T-downstaging as a response to therapy was found, whereas in the remaining 5 patients no therapy response was observed after chemoradiation. A statistically significant difference between both groups was found for the mean PI (P < 0.001; 8.5+/-1.7 ml/min/100 g versus 11.4+/-0.7 ml/min/100 g). Analyzing the cumulative frequency histograms for both groups revealed an optimal discrimination for a P1 value of 12.6 ml/min/100 g. The fraction of pixels in the tumor with PI values larger than 12.6 ml/min/100 g was significantly different (P < 0.001) between therapy-responding (3+/-3.6%) and therapy-nonresponding tumors (21+/-4.3%). The results indicate either a reduced supply of nutrients as well as chemotherapeutic agents attributable to increased shunt flow or highly aggressive tumor cell clusters characterized by increased angiogenic activity. Noninvasive PI measurements by dynamic MRI in rectal carcinoma before therapy seem to be of predictive value for therapy outcome in patients scheduled for preoperative chemoradiation.

Calvarial "doughnut lesions": clinical spectrum of the syndrome, report on a case, and review of the literature.

Many pathologic fractures, lumps on the head, elevated serum alkaline phosphatase (ALP) levels, and dental caries are the main characteristics of the rare autosomal dominantly inherited calvarial "doughnut lesions" (MIM 126550). We report the sporadic case of a 16-year-old patient who has had 10 pathologic fractures between age 6 weeks and 15 years. An elevated serum ALP level was found at age 11 and skull lumps at age 15; radiography showed frontal and parietal round radiolucencies surrounded by sclerotic bone comparable to doughnuts. Magnetic resonance imaging (MRI) showed skull lesions at an early stage. Because the findings are reminiscent of osteogenesis imperfecta (OI), collagen types I, III, and V were analyzed in fibroblasts and shown to be normal in terms of quantities, proportions, electrophoretic mobility, and thermostability. Thus, this rare syndrome can be distinguished from OI by collagen analysis and MRI of the skull at an early stage, even before palpable skull lesions appear.

Monitoring of tumor microcirculation during fractionated radiation therapy in patients with rectal carcinoma: preliminary results and implications for therapy.

PURPOSE: To measure microcirculatory changes during chemoirradiation and to correlate perfusion index (PI) values with therapy outcome. MATERIALS AND METHODS: Perfusion data in 11 patients with cT3 (clinical staging, tumor invaded the perirectal tissue) rectal carcinoma who underwent preoperative chemoirradiation were analyzed. Perfusion data were acquired by using a T1 mapping sequence with a whole-body magnetic resonance (MR) imager. After contrast medium was intravenously infused at a constant rate, concentration-and-time curves were evaluated for arterial blood and tumor. All patients underwent MR imaging before and at constant intervals during chemoirradiation. Clinical stages before therapy were compared with surgical stages after therapy. RESULTS: Spatial and temporal resolution on dynamic T1 maps were sufficient to reveal changes in contrast medium accumulation in the tumor. Comparison of PI values and radiation dose showed a significant increase in the 1st (P: =.003) and 2nd weeks (P: =.01) of treatment; values subsequently returned to pretreatment levels or showed a renewed increase. High initial PI values correlated with greater lymph node downstaging (P: =.042). CONCLUSION: Dynamic T1 mapping provides a suitable tool for monitoring tumor microcirculation during chemoirradiation and offers the potential for individual optimization of therapeutic procedures. Furthermore, these results indicate that the PI map may serve as a prognostic factor.

Staging of rectal cancer by double-contrast MR imaging using the rectally administered superparamagnetic iron oxide contrast agent ferristene and IV gadodiamide injection: results of a multicenter phase II trial.

The aim of this study was to assess the accuracy of double-contrast magnetic resonance imaging (MRI) with rectal application of the superparamagnetic iron oxide contrast agent (SPIO) ferristene and IV gadodiamide for preoperative staging of rectal cancer. In a randomized phase II dose-ranging trial, 113 patients were studied preoperatively with one of four different formulations of ferristene (Abdoscan) as an enema before MRI. T1-weighted spin-echo (T1w SE) and T2w turbo spin-echo (TSE) single-contrast images were obtained as well as T1w SE and gradient-echo (GRE) double-contrast images after IV gadodiamide injection (Omniscan). Images were assessed qualitatively, and TNM tumor stage was compared with histopathology. High-viscosity ferristene formulations were superior to low-viscosity formulations in tumor staging (accuracy 90% vs 74%, P < 0.01). There was no significant difference between high and low iron content ferristene. MRI had a sensitivity of 97%, specificity of 50%, and accuracy of 82% for staging of rectal carcinoma higher than T2 stage. At receiver operator characteristic (ROC) analysis, MR differentiation between T1/T2 and T3/T4 tumor stages yielded a ROC index of 0.848. Double-contrast MRI is an accurate method for preoperative staging of rectal cancer.

[Perfusion-index values evaluated by dynamic magnetic resonance imaging in advanced rectal carcinoma. A new predictor of response to preoperative radiochemotherapy?]. / Mittels dynamischer Magnetresonanztomographie erhaltene Perfusionsindexwerte beim fortgeschrittenen Rektumkarzinom. Eine neue Voraussagemöglichkeit über ein Therapieansprechen bei präoperativer Radiochemotherapie?

PURPOSE: The aim of our study was to evaluate in vivo the influence of tumor microcirculation data on therapy outcome. PATIENTS AND METHODS: Tumor perfusion data of primary rectal carcinoma (n = 14, cT3) who underwent preoperative chemoradiation have been analyzed (Table 1). The perfusion data were acquired at the beginning and at the end of therapy by use of an ultrafast T1-mapping sequence on a whole-body magnetic resonance imager. The gadolinium-DTPA concentration-time-curves were evaluated for arterial blood and tumor before, during and after intravenous constant rate infusion and from that the perfusion index (PI) was calculated. Subsequent resection of the tumors allowed for a correlation of perfusion index values with the pathological classification. RESULTS: Nine patients showed a T downstaging (ypT0-2, group 1), 5 patients did not (ypT3, group 2). The initial mean perfusion index value of group 1 (n = 9) was 8.2 ml/min/100 g (+/- 2) and for group 2 (n = 5) 10.4 ml/min/100 g (+/- 0.4). The difference in perfusion index values before chemoradiation between group 1 and group 2 was significant different (p = 0.012, Mann-Whitney test). The perfusion index value at the end of therapy of group 1 (n = 6) was 9.6 ml/min/100 g (+/- 2.8) and for group 2 (n = 4) 10.7 ml/min/100 g (+/- 1.6). The difference in perfusion index values after chemoradiation between group 1 and group 2 was not significant different (Table 2). CONCLUSION: Our used perfusion index value combines 2 parameters: tumor perfusion and extraction fraction. Therefore a significant negative influence on therapy outcome of high perfusion index values could be explained possibly by areas with a high portion of high perfusion (e.g. av-shunts) and a low extraction fraction (= low exchange of nutrients). However, we could show a significant negative influence of high perfusion index values on therapy outcome (p = 0.012). Because the tumor stage has a significant influence on tumor-free survival, there is a possibility for using initial perfusion index values as a new prognostic factor in rectal carcinoma without sphincter infiltration undergoing a preoperative chemoradiation. To examine this hypotheses a prospective trial is in preparation.

[Development and application of dynamic MR imaging in the evaluation of perfusion changes in rectal carcinoma during radiotherapy in clinical routine. Preliminary results]. / Entwicklung und Anwendung dynamischer MRT-Messungen zur Evaluierung von Perfusionsveränderungen bei Rektumkarzinomen unter Bestrahlung in der klinischen Routine. Erste Ergebnisse.

PURPOSE: This study was aimed at measuring microcirculatory parameters and contrast medium accumulation within the rectal carcinoma during fractionated radiotherapy in the clinical setting. MATERIAL AND METHODS: Perfusion data were observed in patients with rectal carcinoma (n = 8) who underwent a pre-operative combined chemo/radiotherapy. To acquire perfusion data, an ultrafast T1 mapping sequence was carried out on a 1.5-Tesla whole body imager to obtain T1 maps at intervals of 14 or 120 seconds. The overall measurement time was 40 minutes. The transaxial slice thickness (5 mm) was chosen in such a way that both arterial vessels and the tumor could be clearly identified. The gadolinium-DTPA (Gd-DTPA) concentration time curve was evaluated for arterial blood and tumor after intravenous constant rate infusion. The method allows a spatial resolution of 2 x 2 x 5 mm and a temporal resolution of 14 seconds. Patients underwent MR imaging before and at constant intervals during fractionated radiotherapy. RESULTS: Spatial and temporal resolution of dynamic T1 mapping was sufficient to reveal varying CM accumulation levels within the tumor and to identify the great arteries in the pelvis. In 6 patients Gd-DTPA concentration-time-curves were evaluated within the tumor during radiation. Pi index of Gd-DTPA versus radiation dose showed a significant increase in the first or second week of treatment, then either returned slowly to pretreatment level or a renewed increase was observed. The average Pi-value at the beginning was 0.16 (+/- 0.049), reaching highest level of 0.23 (+/- 0.058). In all groups the rise from the Pi-value to the Pi-maximum was statistically significant. The relative increase in perfusion ranged between 20 to 83%. CONCLUSION: The results show, that the ultrafast MR-technique described above provide a suitable tool for monitoring tumor microcirculation during therapeutic interventions and offers the potential for an individualized optimization of therapeutic procedures.

Diagnosis of digital flexor tendon annular pulley disruption: comparison of high frequency ultrasound and MRI.

PURPOSE: The objective of this study is to assess accuracy of ultrasound (US) and MRI to diagnose completely disrupted annular pulley ligaments (APL) of the flexor tendons of the fingers. PATIENTS AND METHODS: In a prospective study 32 patients (all males 18-42 years, mean age 25 years) with clinically suspected annular pulley disruption were studied with US and MRI. As a control group we investigated 40 fingers of 10 healthy volunteers and a non-injured finger of the patients with US. A 10 MHz linear array was used for US examinations and a 1.5 Tesla unit for MRI. Imaging was performed between the accident and surgical repair within 6 weeks. Examinations were performed in an extended and forced flexed finger position. RESULTS: Complete disruption of the APL was diagnosed by US and MRI in 14 cases confirmed by surgery. The typical sign of disruption was a marked volar displacement of the flexor tendon in the area of the torn annular pulley during forced flexion. A distance between tendon and bone at the area of the ruptured pulley of 3 mm during extension and a distance of 5 mm at flexion was typical for complete disruption. CONCLUSION: Both diagnostic modalities, US and MRI are valuable techniques in diagnosing complete disrupted annular pulleys of the flexor tendons.

MR findings in tibial adamantinoma. A case report.

Adamantinoma of the long bones is a rare skeletal tumor and its MR features have seldom been reported. It is difficult to distinguish from other bone lesions (such as osteofibrous dysplasia or osteosarcoma) by means of conventional radiography and CT. MR imaging, however, may be useful in differentiating adamantinoma from such lesions. With this presentation of a typical case, we hope to draw the attention of radiologists to this lesion and contribute information on its MR appearance.

Metallic artifacts in magnetic resonance imaging of patients with spinal fusion. A comparison of implant materials and imaging sequences.

STUDY DESIGN: Devices for spinal fusion were compared with respect to their influence on magnetic resonance images. In addition, different magnetic resonance pulse sequences were evaluated to elicit their susceptibility to imaging artifacts. OBJECTIVES: To determine the implants with the least imaging artifacts as a recommendation for the spine surgeon and to assess the best imaging strategy for the radiologist. SUMMARY OF BACKGROUND DATA: For patients who have had surgical spinal fusion with instrumentation, magnetic resonance imaging is the most favorable diagnostic method. Unfortunately, metallic implants lead to severe degradation of image quality. These artifacts depend on the material of the implant and on the choice of the pulse sequence. METHODS: The fusion devices were mounted on a simple plastic phantom in various combinations and were imaged on 1.5-T magnetic resonance units. Frequently used types of plates and screws made of titanium or steel in various alloys were examined on the phantom with routinely used pulse sequences. The results of these examinations were compared with those in patient studies involving the same implants as well as the same pulse sequences. RESULTS: The least imaging artifacts were caused by titanium implants, especially when using shorter screws, wider screw placement, and thinner titanium plates. Nevertheless, there were distinct image distortions that could lead to erroneous image interpretation. The best images were acquired by spin echo (T1), turbo spin echo (T1, T2), and half Fourier single shot turbo spin echo (HASTE) sequences. Sequences containing any gradient echo components (gradient echo or turbo gradient and spin echo sequence or frequency-selective fat saturation techniques) resulted in the highest amount of image degradation. CONCLUSION: By choosing appropriate spinal fusion devices as well as pulse sequences, postoperative magnetic resonance imaging examinations can give acceptable results, in spite of the presence of metallic implants.

Partial nephrectomy in a cystic partially differentiated nephroblastoma.

Cystic partially differentiated nephroblastoma (CPDN) is a rare neoplastic disorder consisting of a well-demarcated cystic lesion of the kidney where blastemal or other embryonic cells are present in the septa of the cysts. Magnetic resonance imaging can detect the cystic character of the lesion and will produce imaging features that are highly suggestive of either CPDN or cystic nephroma (CN) (synonym: multilocular cyst of the kidney), a benign entity. Although malignant potential exists in CPDN, all cases reported to date have had a favorable prognosis after surgery alone. Partial nephrectomy is considered safe, and the treatment of choice in the newborn period. We report a case of CPDN in a newborn that was successfully treated with partial nephrectomy. More than five years after nephron sparing surgery, the involved kidney shows normal anatomical structure except for a diminished upper pole, no evidence of tumor recurrence and good renal function.

MR and CT anatomy of the axilla.

PURPOSE: To depict the complex anatomy of the axilla with CT and MR imaging. MATERIAL AND METHODS: The axillary regions of 2 cadavers (with arms hyperabducted) were examined by means of CT and MR. In this position the cadavers were frozen and cryosectioned. The anatomical sections documented by the MR and CT images were compared and anatomical structures were designated. To show the reproducibility of the anatomical structures and to find variations, 20 volunteers were also examined by MR, and 20 consecutive patients without axillary symptoms were examined by CT. RESULTS: The complexity of the axilla was excellently shown by both CT and MR, but MR was able to demonstrate more detail in the small vessels and in the brachial plexus. The comparability of the examinations of the different individuals was best in the axial plane. Some differences appeared in the coronal and sagittal planes caused by different positions of the arm. CONCLUSION: Axillary anatomy was demonstrated in detail and was reproducible with CT and MR imaging.