J. Bloem - Academia.edu (original) (raw)

Papers by J. Bloem

JBR-BTR : organe de la Société royale belge de radiologie (SRBR) = orgaan van de Koninklijke Belgische Vereniging voor Radiologie (KBVR)

ABSTRACT

Osteoarthritis and Cartilage, 2013

were frozen or incubated for 24h in serum-free media. Visfatin/NAMPT conformation and release in ... more were frozen or incubated for 24h in serum-free media. Visfatin/NAMPT conformation and release in media by the different tissues was evaluated using Western Blot (WB) and ELISA, respectively. In parallel, proteins were extracted from frozen joint tissues to assess the in situ production and conformation of visfatin/NAMPT by WB. NAMPT enzymatic activity was also assessed in OA synovium using Cyclex colorimetric assay. Primary cultures of mouse chondrocytes and osteoblasts were stimulated with recombinant visfatin/NAMPT (5 mg/mL) for 24h. To determine

European Radiology, 2006

The purpose of this study was to determine the prevalence, extension and signal characteristics o... more The purpose of this study was to determine the prevalence, extension and signal characteristics of fluid-fluid levels in a large series of 700 bone and 700 soft tissue tumors. Out of a multi-institutional database, MRI of 700 consecutive patients with a bone tumor and MRI of 700 consecutive patients with a soft tissue neoplasm were retrospectively reviewed for the presence of fluidfluid levels. Extension (single, multiple and proportion of the lesion occupied by fluid-fluid levels) and signal characteristics on magnetic resonance imaging of fluid-fluid levels were determined. In all patients, pathologic correlation was available. Of 700 patients with a bone tumor, 19 (10 male and 9 female; mean age, 29 years) presented with a fluid-fluid level (prevalence 2.7%). Multiple fluid-fluid levels occupying at least one half of the total volume of the lesion were found in the majority of patients. Diagnoses included aneurysmal bone cyst (ten cases), fibrous dysplasia (two cases), osteoblastoma (one case), simple bone cyst (one case), telangiectatic osteosarcoma (one case), "brown tumor" (one case), chondroblastoma (one case) and giant cell tumor (two cases). Of 700 patients with a soft tissue tumor, 20 (9 males and 11 females; mean age, 34 years) presented with a fluid-fluid level (prevalence 2.9%). Multiple fluid-fluid levels occupying at least one half of the total volume of the lesion were found in the majority of patients. Diagnoses included cavernous hemangioma (12 cases), synovial sarcoma (3 cases), angiosarcoma (1 case), aneurysmal bone cyst of soft tissue (1 case), myxofibrosarcoma (1 case) and high-grade sarcoma "not otherwise specified" (2 cases). In our series, the largest reported in the literature to the best of our knowledge, the presence of fluid-fluid levels is a rare finding with a prevalence of 2.7 and 2.9% in bone and soft tissue tumors, respectively. Fluid-fluid levels remain a non-specific finding and can occur in a wide range of bone and soft tissue tumors, both benign and malignant. Therefore, they cannot be considered diagnostic of any particular type of tumor, and the diagnosis should be made on the basis of other radiological and clinical findings.

Arthroscopy: The Journal of Arthroscopic & Related Surgery, 2004

Mucoid degeneration of the anterior cruciate ligament (ACL) is not a well-known entity. Only 1 ca... more Mucoid degeneration of the anterior cruciate ligament (ACL) is not a well-known entity. Only 1 case of mucoid degeneration of the ACL has been reported in the English-language literature. This article describes 5 cases of mucoid degeneration of the ACL with clinical features, magnetic resonance imaging (MRI) findings, and a method of arthroscopic management of these cases. Type of Study: Case series. Methods: Over a period of 21 months from 1999 to 2001, 5 patients were diagnosed to be suffering from mucoid degeneration of the ACL using MRI, histopathologic, and arthroscopic criteria. All patients presented with progressive knee pain and restriction of flexion without history of a significant trauma or instability preceding the symptoms. MRI showed an increased signal in the substance of the ACL both in the T1-and T2-weighted images, with a mass-like configuration that was reported as a partial or complete tear of the ACL by most radiologists. At arthroscopy, the ACL was homogenous, bulbous, hypertrophied, and taut, occupying the entire intercondylar notch. The ligamentum mucosum was absent in all patients. A debulking of the ACL was performed by a judicious excision of the degenerate mucoid tissue, taking care to leave behind as much of the intact ACL as possible. Releasing it and performing a notchplasty treated impingement of the ACL to the roof and lateral wall. The ACL was not fully excised in any of the patients. Results: All patients were pain free and had recovered full flexion except one who experienced painful flexion beyond 120°. None of the patients showed symptoms of instability. Postoperative MRI performed after at least 12 months in 2 patients showed some intact ACL fibers in a now-thinned ACL mass. Conclusions: Mucoid degeneration of the ACL is a clinical condition afflicting active middle-aged people without a single significant traumatic episode with a specific MRI picture. They respond well to a judicious arthroscopic release of the ACL with notchplasty.

Skeletal Radiology, 2007

Objective The objective was to determine the value of radiographs in young adults with non-acute ... more Objective The objective was to determine the value of radiographs in young adults with non-acute knee symptoms who are scheduled for magnetic resonance imaging (MRI). Materials and methods Nine hundred and sixty-one consecutive patients aged between 16 and 45 years with knee symptoms of at least 4 weeks' duration were prospectively included in three participating hospitals. After applying exclusion criteria, 798 patients remained. Exclusion criteria were previous knee surgery (including arthroscopy) or MRI, history of rheumatoid arthritis, clinical diagnosis of retropatellar chondromalacia, contra-indication for MRI and recent trauma. We identified two groups: group A with no history of trauma (n=332), and group B with an old (>4 weeks) history of trauma (n=466). Patients had a standardized history taken, and underwent a physical exam, antero-posterior (AP) and lateral radiographs and MRI. We evaluated the radiographs and MRI for osseous lesions, articular surface lesions, fractures, osteoarthritis, loose bodies, bone marrow edema and incidental findings. Subsequently, patients with osseous abnormalities (Kellgren grade 1 and 2 excluded) on radiographs and a matched control group was evaluated again using MRI without radiographs. Results Median duration of symptoms was 20 weeks. In group A, radiographs showed 36 osseous abnormalities in 332 patients (10.8%). Only 13 of these, all Kellgren grade 1 osteoarthritis, were not confirmed on MRI. MRI showed 72 (21.7%) additional abnormalities not confirmed on radiographs. In group B, radiographs showed 40 osseous abnormalities (8.6%) in 466 patients. Only 15 of these, all Kellgren grade 1 osteoarthritis, were not confirmed on MRI. MRI showed 194 (41.6%) additional abnormalities not confirmed on radiographs. The second evaluation of MRI without radiographs in 34 patients was identical to the first MRI evaluation. Common lesions were significantly more often diagnosed with MRI than with radiographs. Conclusion Radiographs should not be obtained routinely when MRI is being performed in young adults with nonacute knee complaints because the yield and added value to MRI are low.

Spine, 2009

A prospective study on 24 patients with spinal osteoid osteoma treated with radiofrequency ablati... more A prospective study on 24 patients with spinal osteoid osteoma treated with radiofrequency ablation (RFA). To determine if and when computed tomography (CT)-guided RFA is a safe and effective treatment for spinal osteoid osteomas. Surgery has been considered the standard treatment for spinal osteoid osteomas. Surgery may cause spinal instability, infection, and nervous injury. We evaluated CT-guided RFA as an alternative treatment. A total of 28 RFA procedures in 24 patients with spinal osteoid osteoma were performed, using a 5-mm noncooled electrode. Clinical symptoms and spinal deformity were evaluated before and after the procedure. Unsuccessful treatment was defined as the presence of residual or recurrent symptoms. The mean follow-up was 72 months (range: 9-142 months). Nineteen (79%) patients were successfully treated after 1 RFA, and all except one after repeat RFA. One patient with nerve root compression needed further surgery. No complications were observed. Spinal deformity persisted in 3 of 7 patients after successful RFA. CT-guided RFA is a safe and effective treatment for spinal osteoid osteoma. Surgery should be reserved for lesions causing nerve root compression.

PURPOSE To evaluate the effectiveness of MR imaging and chest X-ray or CT at standardized interva... more PURPOSE To evaluate the effectiveness of MR imaging and chest X-ray or CT at standardized intervals in detecting first local and distant recurrence in patients with primary soft tissue sarcomas (STS) and extra-abdominal aggressive fibromatoses (AF). METHOD AND MATERIALS Between March 1999 and March 2001, we prospectively included 64 STS and 7 AF. Patients were observed at 3 weeks, 3, 6, 12, 18 and 24 months after treatment by taking patient’s history, physical examination, chest X-ray or CT, and MR imaging. After two years, patients were observed annually by taking patient’s history and physical examination. Median follow-up was 45 months, range 35-59 months. Excluded were 14 patients with locally irresectable tumors and 12 patients with diffuse metastatic disease at presentation. Two patients were lost from follow-up. Patient records and imaging reports were reviewed to determine local and distant recurrence. RESULTS Recurrence (local and/or distant) occurred in 17 of 43 (40%) pati...

Radiology, 2004

To prospectively evaluate static and dynamic gadopentetate dimeglumine-enhanced magnetic resonanc... more To prospectively evaluate static and dynamic gadopentetate dimeglumine-enhanced magnetic resonance (MR) imaging relative to nonenhanced MR imaging in differentiation of benign from malignant soft-tissue lesions and to evaluate which MR imaging parameters are most predictive of malignancy, with associated interobserver variability. One hundred forty consecutive patients (78 male patients [median age, 51 years], 62 female patients [median age, 53 years]) with a soft-tissue mass underwent nonenhanced static and dynamic contrast material-enhanced MR imaging. Diagnosis was based on histologic findings in surgical specimens (86 of 140), findings at core-needle biopsy (43 of 140), or results of all imaging procedures with clinical follow-up (11 of 140). Multivariate logistic regression analysis was used to identify the best combination of MR imaging parameters that might be predictive of malignancy. Subjective overall performance of two observers was evaluated with receiver operating characteristic analysis. For subjective overall diagnosis, area under the receiver operating characteristic curve, a measure for diagnostic accuracy, was significantly larger for combined nonenhanced and contrast-enhanced MR imaging than it was for nonenhanced MR imaging alone, with no significant difference between observers. Multivariate analysis of all lesions revealed that combined nonenhanced static and dynamic contrast-enhanced MR imaging parameters were significantly superior to nonenhanced MR imaging parameters alone and to nonenhanced MR imaging parameters combined with static contrast-enhanced MR imaging parameters in prediction of malignancy. The most discriminating parameters were presence of liquefaction, start of dynamic enhancement (time interval between start of arterial and tumor enhancement), and lesion size (diameter). Results for extremity lesions were the same, with one exception: With dynamic contrast-enhanced MR imaging parameters, diagnostic performance of one observer did not improve. Static and dynamic contrast-enhanced MR imaging, when added to nonenhanced MR imaging, improved differentiation between benign and malignant soft-tissue lesions.

European Radiology, 2003

The objective of this study was to evaluate whether dynamic contrast-enhanced MR imaging can dete... more The objective of this study was to evaluate whether dynamic contrast-enhanced MR imaging can determine tumor response and localize residual viable tumor after isolated limb perfusion (ILP) chemotherapy in soft tissue tumors. Twelve consecutive patients, with histologically proven high-grade soft tissue sarcoma, prospectively underwent nonenhanced MR and dynamic contrastenhanced MR imaging before and after ILP. Tumor volume was measured on non-enhanced MR images. The temporal change of signal intensity in a region of interest on dynamic contrast-enhanced MR images was plotted against time. Start, pattern, and progression of enhancement were recorded. Histopathologic response was defined as complete response if no residual viable tumor was present, partial remission if <50% viable tumor was present, and no change if ≥50% viable tumor was present in the resection specimen. Resected specimens for correlation with histopathology were available for 10 patients; 5 patients had partial remission and 5 had no change. Volume measurements correctly predicted tumor response in 6 of 10 patients. Dynamic contrastenhanced MR correctly predicted tumor response in 8 of 10 patients. Early rapidly progressive enhancement correlated histologically with residual viable tumor. Late and gradual, or absence of enhancement, was associated with necrosis, predominantly centrally located, or granulation tissue. These preliminary results show that dynamic contrastenhanced MR imaging offers potential for non-invasive monitoring of response to isolated limb perfusion in soft tissue sarcomas due to identification of residual areas of viable tumor and subsequently may provide clinically useful information with regards to timing and planning of additional surgery. Further prospective studies in a larger patient population is warranted.

Arthritis & rheumatology (Hoboken, N.J.), 2015

To determine possible patterns of synovitis on contrast-enhanced magnetic resonance imaging (CE-M... more To determine possible patterns of synovitis on contrast-enhanced magnetic resonance imaging (CE-MRI) and its relation to pain and severity in patients with radiographic knee osteoarthritis (OA). In total, 86 patients (mean age 62 years, 66% women, median body mass index 29 kg/m(2) ) with symptomatic knee OA (Kellgren/Lawrence radiographic score 3) were included. T1-weighted, gadolinium-chelate-enhanced MRI with fat suppression was used to semiquantitatively score the extent of synovitis at 11 knee sites (total score range 0-22). Self-reported pain was assessed with 3 standardized questionnaires. Principal components analysis (PCA) was used to investigate patterns (the location and severity) of synovitis. Subsequently, these patterns were assessed for associations with pain measures and radiographic severity in adjusted logistic regression models. Synovitis was observed in 86 patients and was found to be generally mild on CE-MRI (median total synovitis score 7, range 0-16). The media...

Osteoarthritis and Cartilage, 2013

Skeletal Radiology, 2005

Objective: To develop a scoring system for quantifying osteoarthritic changes of the knee as iden... more Objective: To develop a scoring system for quantifying osteoarthritic changes of the knee as identified by magnetic resonance (MR) imaging, and to determine its inter-and intra-observer reproducibility, in order to monitor medical therapy in research studies. Design and patients: Two independent observers evaluated 25 consecutive MR examinations of the knee in patients with previously defined clinical symptoms and radiological signs of osteoarthritis. We acquired on a 1.5 T system: coronal and sagittal proton density-and T2-weighted dual spin echo (SE) images, sagittal three-dimensional T1-weighted gradient echo (GE) images with fat suppression, and axial dual turbo SE images with fat suppression. Images were scored for the presence of cartilaginous lesions, osteophytes, subchondral cysts, bone marrow edema, and for meniscal abnormalities. Presence and size of effusion, synovitis and Baker's cyst were recorded. All parameters were ranked on a previously defined, semiquantitative scale, reflecting increasing severity of findings. Kappa, weighted kappa and intraclass correlation coefficient (ICC) were used to determine interand intra-observer variability. Results: Inter-observer reproducibility was good (ICC value 0.77). Interand intra-observer reproducibility for individual parameters was good to very good (inter-observer ICC value 0.63-0.91; intra-observer ICC value 0.76-0.96). Conclusion: The presented comprehensive MR scoring system for osteoarthritic changes of the knee has a good to very good inter-observer and intra-observer reproducibility. Thus the score form with its definitions can be used for standardized assessment of osteoarthritic changes to monitor medical therapy in research studies.

Publications by J. Bloem

Contrast enhancement with gadopentetate dimeglumine has been advocated to increase the efficacy o... more 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. 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. 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. 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.

Books and Scientific Papers by J. Bloem

Skeletal Radiology, 1994

Magnetic resonance (MR) imaging was performed in 26 patients with Ewing's sarcoma of bone precedi... more 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.

Radiographics : a review publication of the Radiological Society of North America, Inc, 1987

Although CT should be used as the initial procedure, MRI potentially can identify most adrenal ma... more Although CT should be used as the initial procedure, MRI potentially can identify most adrenal masses without the hazard of ionizing radiation or the injection of iodinated contrast material.

JBR-BTR : organe de la Société royale belge de radiologie (SRBR) = orgaan van de Koninklijke Belgische Vereniging voor Radiologie (KBVR)

ABSTRACT

Osteoarthritis and Cartilage, 2013

European Radiology, 2006

Arthroscopy: The Journal of Arthroscopic & Related Surgery, 2004

Skeletal Radiology, 2007

Spine, 2009

Radiology, 2004

European Radiology, 2003

Arthritis & rheumatology (Hoboken, N.J.), 2015

Osteoarthritis and Cartilage, 2013

Skeletal Radiology, 2005

Skeletal Radiology, 1994

Radiographics : a review publication of the Radiological Society of North America, Inc, 1987