Long-Term Halo Follow-Up Confirms Less Invasive Treatment of Low-Grade Cartilaginous Tumors with Radiofrequency Ablation to Be Safe and Effective

Background: Radiofrequency ablation (RFA) is a minimally invasive alternative in the treatment of bone tumors. Long-term follow-up has not been described in current literature. Detailed analysis of mid- and long-term follow-up after RFA treatment for a cohort of patients with low-grade cartilaginous tumors (atypical cartilaginous tumors and enchondroma) was performed. The results, complications, and development of halo dimensions over time are presented. Methods: Data of all patients with an RFA procedure for an ACT between 2007-2018 were included. Ablation area is visible on baseline MRI, 3 months post-procedure, and is called halo. Volume was measured on MR images and compared to different follow-up moments to determine the effect of time on halo volume. Follow-up was carried out 3 months and 1, 2, 5, and 7 years after the procedure. Occurrence of complications and recurrences were assessed. Results: Of the 137 patients included, 82 were analyzed. Mean follow-up time was 43.6 months. Ablation was complete in 73 cases (89.0%). One late complication occurred, while no recurrences were seen. Halo dimensions of height, width, and depth decreased with a similar rate, 21.5% on average in the first year. Subsequently, this decrease in halo size continues gradually during follow-up, indicating bone revitalization. Conclusion: RFA is a safe and effective treatment in low-grade cartilaginous tumors with an initial success rate of 89.0%. Extended follow-up shows no local recurrences and gradual substitution of the halo with normal bone

Can FDG-PET/CT replace blind bone marrow biopsy of the posterior iliac crest in Ewing sarcoma?

OBJECTIVE: To determine and compare the value of (18)F-fluoro-2-deoxy-D-glucose positron emission tomography/computed tomography (FDG-PET/CT) to blind bone marrow biopsy (BMB) of the posterior iliac crest in detecting metastatic bone marrow involvement in newly diagnosed Ewing sarcoma. MATERIALS AND METHODS: This retrospective study included 20 patients with newly diagnosed Ewing sarcoma who underwent pretreatment FDG-PET/CT and a total of 38 blind BMBs (two unilateral and 18 bilateral) of the posterior iliac crest. FDG-PET/CT scans were evaluated for bone marrow involvement, both in the posterior iliac crest and other sites, and compared to blind BMB results. RESULTS: FDG-PET/CT was positive for bone marrow involvement in 7/38 posterior iliac crests, whereas BMB was positive in 5/38 posterior iliac crests. FDG-PET/CT and BMB results in the posterior iliac crest agreed in 36/38 cases (94.7%, 95% confidence interval [CI]: 82.7-98.5%). On a patient level, FDG-PET/CT was positive for bone marrow involvement in 4/20 patients, whereas BMB of the posterior iliac crest was positive in 3/20 patients. On a patient level, FDG-PET/CT and BMB results agreed in 19/20 patients (95.0%, 95% CI: 76.4-99.1%). The only discrepancies between FDG-PET/CT and BMB were observed in two BMBs of one patient. Both BMBs in this patient were negative, whereas FDG-PET/CT indicated bilateral posterior iliac crest involvement and also extensive bone marrow involvement elsewhere. CONCLUSIONS: FDG-PET/CT appears to be a valuable method for metastatic bone marrow assessment in newly diagnosed Ewing sarcoma. The routine use of blind BMB of the posterior iliac crest should be reconsidered when FDG-PET/CT is available

Children's spatial analysis of simple and complex Hierarchical Patterns in a Drawing Task

BACKGROUND: Primary tumor volume is as an important and independent prognostic factor in Ewing sarcoma. However, the observer variability of magnetic resonance imaging (MRI)-based primary tumor volume measurements in newly diagnosed Ewing sarcoma has never been investigated. Furthermore, it is unclear how MRI-based volume measurements compare to (18)F-fluoro-2-deoxy-D-glucose (FDG) positron emission tomography (PET)-based volume measurements. This study aimed to determine the observer variability of simplified MRI-based primary tumor volume measurements in newly diagnosed treatment-naive Ewing sarcoma and to compare them to the actual primary tumor volume at MRI and the FDG-PET-based metabolically active tumor volume (MATV). MATERIAL AND METHODS: Twenty-nine newly diagnosed Ewing sarcoma patients with pretreatment MRI (of whom 11 also underwent FDG-PET) were included. Both exact and dichotomized (according to the proposed threshold of 200 mL) primary tumor volume measurements were analyzed. RESULTS: Mean inter- and intraobserver differences of MRI-based simplified tumor volume ± limits of agreement varied between 15-42 ± 155-204 mL and between 9-16 ± 64-250 mL, respectively. Inter- and intraobserver agreements of dichotomized MRI-based simplified tumor volume measurements was very good (κ = 0.827-1.000). Mean difference between simplified and actual tumor volumes at MRI ± limits of agreement was 60 ± 381 mL. Agreement between dichotomized simplified and actual tumor volumes at MRI was very good (κ = 0.839). Mean difference between MRI-based simplified tumor volume and MATV ± limits of agreement was 181 ± 549 mL and almost significantly different (p = .0581). Agreement between dichotomized MRI-based simplified tumor volume and MATV was moderate (κ = 0.560). CONCLUSIONS: Exact MRI-based simplified primary tumor volume measurements in Ewing sarcoma suffer from considerable observer variability, but observer agreement of dichotomized measurements (≤200 mL vs. >200 mL) is very good and generally matches MRI-based actual volume measurements. MRI-based primary tumor volume measurements poorly-moderately agree with and tend to be lower than the MATV

Early detection of heart function abnormality by native T1:a comparison of two T1 quantification methods

Objective To compare the robustness of native T1 mapping using mean and median pixel-wise quantification methods. Methods Fifty-seven consecutive patients without overt signs of heart failure were examined in clinical routine for suspicion of cardiomyopathy. MRI included the acquisition of native T1 maps by a motion-corrected modified Look-Locker inversion recovery sequence at 1.5 T. Heart function status according to four established volumetric left ventricular (LV) cardio MRI parameter thresholds was used for retrospective separation into subgroups of normal (n = 26) or abnormal heart function (n = 31). Statistical normality of pixel-wise T1 was tested on each myocardial segment and mean and median segmental T1 values were assessed. Results Segments with normally distributed pixel-wise T1 (57/58%) showed no difference between mean and median quantification in either patient group, while differences were highly significant (p <0.001) for the respective 43/42% non-normally distributed segments. Heart function differentiation between two patient groups was significant in 14 myocardial segments (p <0.001-0.040) by median quantification compared with six (p <0.001-0.042) by using the mean. The differences by median quantification were observed between the native T1 values of the three coronary artery territories of normal heart function patients (p = 0.023) and insignificantly in the abnormal patients (p = 0.053). Conclusion Median quantification increases the robustness of myocardial native T1 definition, regardless of statistical normality of the data. Compared with the currently prevailing method of mean quantification, differentiation between LV segments and coronary artery territories is better and allows for earlier detection of heart function impairment

Radiofrequency ablation of atypical cartilaginous tumors in long bones:a retrospective study

Purpose: To determine the size of the ablation zone after radiofrequency ablation (RFA) of atypical cartilaginous bone tumors (ACT) using temperature-controlled 20 and 30 mm RFA straight non-cooled electrodes. Materials and methods: Sixteen patients with ACT in their long bones, who had undergone a single-session single-application CT-guided temperature-controlled RFA, were included retrospectively in the study. Tumors with a diameter of 10-25 mm were treated with 20 mm electrodes (n = 10), and tumors of 25-35 mm, with 30 mm electrodes (n = 6). The ablated zone was measured after three months on MRI images. Results: All the tumors were within the ablated zone on the 3-month follow-up MRI scan. The mean ablation time with the electrode, at a target temperature of 90 degrees C, was 7.6 minutes (range 6-10). The median of the largest ablation diameters, on applying the 20 and 30 mm electrodes, were 42 mm (IQR 8.5, range 30-51 mm) and 44.5 mm (IQR 4.5, range 42-63 mm), respectively. Conclusions: All the retrospectively viewed tumors in the long bones of ACT patients treated with RFA were completely ablated. The ablation zone diameters in the bones were larger than expected, when compared to other tissues, such as the liver

Culture yield of repeat percutaneous image-guided biopsy after a negative initial biopsy in suspected spondylodiscitis:a systematic review

Objective: To systematically review the published data on the culture yield of a repeat (second) percutaneous image-guided biopsy after negative initial biopsy in suspected spondylodiscitis. Materials and methods: A systematic search was performed of the PubMed/Medline and Embase databases. The methodological quality of the studies included was assessed. The proportions of positive cultures among all initial biopsies and second biopsies (after a negative initial biopsy) were calculated for each study and assessed for heterogeneity (defined as I2 > 50%). Results: Eight studies, comprising a total of 107 patients who underwent a second percutaneous image-guided biopsy after a culture-negative initial biopsy in suspected spondylodiscitis, were included. All eight studies were at risk of bias and were concerning with regard to applicability, particularly patient selection, flow of patients through the study, and timing of the biopsy. The proportions of positive cultures among all initial biopsies ranged from 10.3 to 52.5%, and were subject to heterogeneity (I2 = 73.7%). The proportions of positive cultures among all second biopsies after negative initial biopsy ranged from 0 to 60.0%, and were not subject to heterogeneity (I2 = 38.7%). Conclusion: Although a second percutaneous image-guided biopsy may have some value in patients with suspected spondylodiscitis, its exact value remains unclear, given the available poor-quality evidence. Future well-designed studies are needed to determine the role of a second percutaneous image-guided biopsy in this setting. Such studies should clearly describe the spectrum of patients that was selected for a second percutaneous image-guided biopsy, the method of biopsy, and differences compared with the first biopsy, if any

Diagnostic value of MRI signs in differentiating Ewing sarcoma from osteomyelitis

Background: The value of magnetic resonance imaging (MRI) signs in differentiating Ewing sarcoma from osteomyelitis has not be thoroughly investigated. Purpose: To investigate the value of various MRI signs in differentiating Ewing sarcoma from osteomyelitis. Material and Methods: Forty-one patients who underwent MRI because of a bone lesion of unknown nature with a differential diagnosis that included both Ewing sarcoma and osteomyelitis were included. Two observers assessed several MRI signs, including the transition zone of the bone lesion, the presence of a soft-tissue mass, intramedullary and extramedullary fat globules, and the penumbra sign. Results: Diagnostic accuracies for discriminating Ewing sarcoma from osteomyelitis were 82.4% and 79.4% for the presence of a soft-tissue mass, and 64.7% and 58.8% for a sharp transition zone of the bone lesion, for readers 1 and 2 respectively. Inter-observer agreement with regard to the presence of a soft-tissue mass and the transition zone of the bone lesion were moderate (κ = 0.470) and fair (κ = 0.307), respectively. Areas under the receiver operating characteristic curve of the diameter of the soft-tissue mass (if present) were 0.829 and 0.833, for readers 1 and 2 respectively. Mean inter-observer difference in soft-tissue mass diameter measurement ± limits of agreement was 35.0 ± 75.0 mm. Diagnostic accuracies of all other MRI signs were all < 50%. Conclusion: Presence and size of a soft-tissue mass, and sharpness of the transition zone, are useful MRI signs to differentiate Ewing sarcoma from osteomyelitis, but inter-observer agreement is relatively low. Other MRI signs are of no value in this setting

Radiofrequency ablation in the treatment of atypical cartilaginous tumours in the long bones:Lessons learned from our experience

BACKGROUND: Surgery is the cornerstone of treatment of symptomatic cartilaginous neoplasms. We previously studied the application of radiofrequency ablation of atypical cartilaginous tumours in the long bones. The purpose of the present study was to investigate the additional effect of placing multiple needles and a longer procedure duration on the proportion of completely ablated tumours. Post-ablation MRI findings and the occurrence of complications were also assessed. METHODS: We prospectively included 24 patients with atypical cartilaginous tumours in the long bones. Patients underwent CT-guided radiofrequency ablation followed by curettage with adjuvant phenolisation 3 months later, retrieving material assessed for viable tumour. Before curettage, gadolinium-enhanced MRI was performed to check for residual tumour. The occurrence of complications was noted. RESULTS: Complete tumour ablation was achieved in 17 out of 24 patients (71%). Complete ablation was achieved in 5 of the 6 cases (83%) when multiple needles were used in tumours ≥30 mm. There was incomplete ablation in 8% of patients. Post-ablation gadolinium-enhanced MRI findings agreed with the histological results in 17 out of 23 cases and there was a negative predictive value of 83%. One patient suffered a fracture after radiofrequency ablation. CONCLUSION: Radiofrequency ablation could be an alternative to curettage when treating atypical cartilaginous tumours in the long bones. It was shown that multiple needle placement in addition to longer duration of the ablation procedure is an effective measure in achieving complete ablation in tumours ≥30 mm. Gadolinium-enhanced MRI has a negative predictive value of 83% and could guide post-ablation follow-up

CT-guided biopsy in suspected spondylodiscitis:microbiological yield, impact on antimicrobial treatment, and relationship with outcome

Purpose: To investigate the clinical impact of CT-guided biopsy, as performed in routine clinical practice, in patients with suspected spondylodiscitis on MRI in terms of culture yield, impact on antimicrobial treatment, and outcome. Methods: This study included 64 patients with MRI findings compatible with spondylodiscitis who underwent CT-guided biopsy. Results: Initial CT-guided biopsies were culture-positive in 20/64 (31.3%, 95% confidence interval [CI] 21.2–43.3%). Repeat CT-guided biopsies (after initial negative biopsy) were culture-positive in an additional 5/15 (33.3%, 95% CI 15.2–58.3%). Serum leukocytes, C-reactive protein, pre-biopsy use of antibiotics, neurological symptoms, MRI findings, vertebral height loss, and hyperkyphosis were not significantly different between culture-positive and culture-negative cases (P = 0.214–1.000); 75% (15/20) of initial CT-guided biopsies that were culture-positive provided additional information to clinicians for guiding antibiotic treatment. Sixty-two of 64 patients (96.9%, 95% CI 89.3–99.1%) would have been adequately treated if a strategy was followed that would subject all patients without clinical findings suspicious for “atypical” microorganisms and negative blood cultures to empirical antibiotics (i.e., clindamycin for coverage of Gram-positive bacteria) without using biopsy results to determine the optimal antibiotic regimen. Outcome within 6 months (development of neurologic or orthopedic complications, surgery, and death) was not significantly different (P = 0.751) between culture-positive and culture-negative patients. Conclusions: Although CT-guided biopsies are culture-positive in a minority of cases, the majority of positive cultures are useful to tailor antibiotic treatment. Empirical treatment with clindamycin may cover almost all micro-organisms in positive biopsy specimens, provided patients are not immunocompromised. Outcome appears similar between culture-positive and culture-negative patients

A single digital droplet PCR assay to detect multiple KIT exon 11 mutations in tumor and plasma from patients with gastrointestinal stromal tumors

__Background:__ Gastrointestinal stromal tumors (GISTs) are characterized by oncogenic KIT mutations that cluster in two exon 11 hotspots. The aim of this study was to develop a single, sensitive, quantitative digital droplet PCR (ddPCR) assay for the detection of common exon 11 mutations in both GIST tumor tissue and in circulating tumor DNA (ctDNA) isolated from GIST patients' plasma. __Methods:__ A ddPCR assay was designed using two probes that cover both hotspots. Available archival FFPE tumor tissue from 27 consecutive patients with known KIT exon 11 mutations and 9 randomly selected patients without exon 11 mutations were tested. Plasma samples were prospectively collected in a multicenter bio-databank from December 2014. ctDNA was analyzed of 22 patients with an exon 11 mutation and a baseline plasma sample. __Results:__ The ddPCR assay detected the exon 11 mutation in 21 of 22 tumors with exon 11 mutations covered by the assay. Mutations in ctDNA were detected at baseline in 13 of 14 metastasized patien