Nicolas Theumann

University Hospital of Lausanne, Lausanne, Vaud, Switzerland

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Publications (111)223.19 Total impact

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    ABSTRACT: PURPOSE: To determine the value of applying finger trap distraction during direct MR arthrography of the wrist to assess intrinsic ligament and triangular fibrocartilage complex (TFCC) tears. MATERIALS AND METHODS: Twenty consecutive patients were prospectively investigated by three-compartment wrist MR arthrography. Imaging was performed with 3-T scanners using a three-dimensional isotropic (0.4mm) T1-weighted gradient-recalled echo sequence, with and without finger trap distraction (4kg). In a blind and independent fashion, two musculoskeletal radiologists measured the width of the scapholunate (SL), lunotriquetral (LT) and ulna-TFC (UTFC) joint spaces. They evaluated the amount of contrast medium within these spaces using a four-point scale, and assessed SL, LT and TFCC tears, as well as the disruption of Gilula's carpal arcs. RESULTS: With finger trap distraction, both readers found a significant increase in width of the SL space (mean Δ=+0.1mm, p≤0.040), and noticed more contrast medium therein (p≤0.035). In contrast, the differences in width of the LT (mean Δ=+0.1mm, p≥0.057) and UTFC (mean Δ=0mm, p≥0.728) spaces, as well as the amount of contrast material within these spaces were not statistically significant (p=0.607 and ≥0.157, respectively). Both readers detected more SL (Δ=+1, p=0.157) and LT (Δ=+2, p=0.223) tears, although statistical significance was not reached, and Gilula's carpal arcs were more frequently disrupted during finger trap distraction (Δ=+5, p=0.025). CONCLUSION: The application of finger trap distraction during direct wrist MR arthrography may enhance both detection and characterisation of SL and LT ligament tears by widening the SL space and increasing the amount of contrast within the SL and LT joint spaces.
    European journal of radiology 06/2013; · 2.65 Impact Factor
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    ABSTRACT: A 55-year-old man presented with a 2-year history of progressive pain in the right arm, which persisted at night and was exacerbated by exposure to cold. His past medical history was relevant for type 1 diabetes mellitus and hypertension. There was no history of cancer or prior trauma. Physical examination revealed exquisite point tenderness upon palpation of a 5-mm sub-cutaneous nodule located on the lateral aspect of the right arm, approximately 10 cm distal to the greater tuberosity of humer-us. No overlying epidermal abnormality was noted. The axil-lary lymph nodes felt normal. Fig. 1 Longitudinal a B-mode and b color Doppler US images (17–5 MHz linear probe) of the lateral aspect of the right arm Fabio Becce and Emilie Uldry contributed equally to this work. The diagnosis can be found at doi:10.
    04/2013; 42:587-588.
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    ABSTRACT: The objective of our study was to report the MRI findings in dorsal fractures of the triquetrum, with an emphasis on dorsal carpal ligament injuries. A total of 21 patients (16 men, five women; mean age, 41.9 years) with acute or subacute (≤ 6 weeks) dorsal triquetral fractures on radiography and MRI were included in this two-center retrospective study. MRI of the wrist was performed on 3-T units with transverse T1-weighted, coronal or transverse (or both) fat-suppressed T2weighted, transverse gadolinium-enhanced fat-suppressed T1-weighted turbo spin-echo, and 3D gadolinium-enhanced fat-suppressed T1-weighted gradient-recalled echo sequences. Three musculoskeletal radiologists evaluated the ulnar styloid process index (USPI) on radiographs and the following MRI features: fracture pattern (types 1-6), bone fragment size and displacement, bone marrow edema distribution, and dorsal carpal ligament tears. Eight type 1, one type 2, six type 3, five type 4, and one type 5 fractures were identified. These fractures were associated with 14 (66.7%), 17 (81.0%), and 16 (76.2%) tears of the dorsal radiocarpal, ulnotriquetral, and intercarpal ligaments, respectively. There was no correlation between bone marrow edema distribution and dorsal carpal ligament injuries (all p > 0.05). The mean (± SD) bone fragment volume and displacement were 205 ± 157 mm(3) and 1.0 ± 1.1 mm, respectively. The mean USPI was 0.21 ± 0.10. Dorsal fractures of the triquetrum are frequently associated with dorsal carpal ligament injuries. Bone marrow edema distribution is not correlated with these ligament tears.
    American Journal of Roentgenology 03/2013; 200(3):608-17. · 2.74 Impact Factor
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    ABSTRACT: PURPOSE: To investigate magnetization transfer (MT) effects as a new source of contrast for imaging and tracking of peripheral foot nerves. MATERIALS AND METHODS: Two sets of 3D spoiled gradient-echo images acquired with and without a saturation pulse were used to generate MT ratio (MTR) maps of 260 μm in-plane resolution for eight volunteers at 3T. Scan parameters were adjusted to minimize signal loss due to T2 dephasing, and a dedicated coil was used to improve the inherently low signal-to-noise ratio of small voxels. Resulting MTR values in foot nerves were compared with those in surrounding muscle tissue. RESULTS: Average MTR values for muscle (45.5 ± 1.4%) and nerve (21.4 ± 3.1%) were significantly different (P < 0.0001). In general, the difference in MTR values was sufficiently large to allow for intensity-based segmentation and tracking of foot nerves in individual subjects. This procedure was termed MT-based 3D visualization. CONCLUSION: The MTR serves as a new source of contrast for imaging of peripheral foot nerves and provides a means for high spatial resolution tracking of these structures. The proposed methodology is directly applicable on standard clinical MR scanners and could be applied to systemic pathologies, such as diabetes. J. Magn. Reson. Imaging 2012. © 2012 Wiley Periodicals, Inc.
    Journal of Magnetic Resonance Imaging 09/2012; · 2.57 Impact Factor
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    ABSTRACT: PURPOSE: To assess the value of adding axial traction to direct MR arthrography of the shoulder, in terms of subacromial and glenohumeral joint space widths, and coverage of the superior labrum-biceps tendon complex and articular cartilage by contrast material. MATERIALS AND METHODS: Twenty-one patients investigated by direct MR arthrography of the shoulder were prospectively included. Studies were performed with a 3 Tesla (T) unit and included a three-dimensional isotropic fat-suppressed T1-weighted gradient-recalled echo sequence, without and with axial traction (4 kg). Two radiologists independently measured the width of the subacromial, superior, and inferior glenohumeral joint spaces. They subsequently rated the amount of contrast material around the superior labrum-biceps tendon complex and between glenohumeral cartilage surfaces, using a three-point scale: 0 = no, 1 = partial, 2 = full. RESULTS: Under traction, the subacromial (Δ = 2.0 mm, P = 0.0003), superior (Δ = 0.7 mm, P = 0.0001) and inferior (Δ = 1.4 mm, P = 0.0006) glenohumeral joint space widths were all significantly increased, and both readers noted significantly more contrast material around the superior labrum-biceps tendon complex (P = 0.014), and between the superior (P = 0.001) and inferior (P = 0.025) glenohumeral cartilage surfaces. CONCLUSION: Direct MR arthrography of the shoulder under axial traction increases subacromial and glenohumeral joint space widths, and prompts better coverage of the superior labrum-biceps tendon complex and articular cartilage by contrast material. J. Magn. Reson. Imaging 2012;. © 2012 Wiley Periodicals, Inc.
    Journal of Magnetic Resonance Imaging 09/2012; · 2.57 Impact Factor
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    ABSTRACT: To evaluate the influence of shorter- and longer-acting intra-articular anaesthetics on post-arthrographic pain. 154 consecutive patients investigated by MR or CT arthrographies were randomly assigned to one of the following groups: 1--intra-articular contrast injection only; 2--lidocain 1% adjunction; or 3--bupivacain 0.25% adjunction. Pain was assessed before injection, at 15 min, 4 h, 1 day and 1 week after injection by visual analogue scale (VAS). At 15 min, early mean pain score increased by 0.96, 0.24 and 0 in groups 1, 2 and 3, respectively. Differences between groups 1 & 3 and 1 & 2 were statistically significant (p=0.003 and 0.03, respectively), but not between groups 2 & 3 (p=0.54). Delayed mean pain score increase was maximal at 4 h, reaching 1.60, 1.22 and 0.29 in groups 1, 2 and 3, respectively. Differences between groups 1 & 2 and 2 & 3 were statistically significant (p=0.002 and 0.02, respectively), but not between groups 1 & 2 (p=0.46). At 24 h and 1 week, the interaction of local anaesthetics with increase in pain score was no longer significant. Results were independent of age, gender and baseline VAS. Intra-articular anaesthesia may significantly reduce post-arthrographic pain. Bupivacain seems to be more effective than lidocain to reduce both early and delayed pain.
    European journal of radiology 07/2012; 81(9):e957-61. · 2.65 Impact Factor
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    ABSTRACT: Pregnancy-associated osteoporosis usually appears during the first pregnancy and does not affect the followings. We report two cases where non-traumatic fractures have been diagnosed shortly after delivery of second pregnancies. Wide investigations could not find a cause of secondary osteoporosis. In the first case we came to the diagnosis of pregnancy-associated osteoporosis and an intravenous treatment of ibandronate has been prescribed. In the second case the bone mineral density (BMD) being almost normal and the localisation of the fracture being atypical, we concluded to a fracture of non-osteoporotic origin, probably due to mechanical stress during pregnancy. No therapy against osteoporosis has been prescribed.
    Praxis 07/2012; 101(14):923-8.
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    ABSTRACT: Vertebral osteoporotic fracture (VOF) is a major problem of public health. Surgical treatments such as vertebroplasty and kyphoplasty are interesting adjuvant treatments for the management of osteoporosis. A consensus proposed by the principal contributors of this management is important. Regarding the actual data, we propose a vertebroplasty or a kyphoplasty for all patients suffering of an acute VOF. If a previous kyphosis or an important local kyphosis exists, secondary to the acute VOF or others, we propose a kyphoplasty. If the VOF is older and the conservative treatment is inefficient, we propose a vertebroplasty. In all cases, a specific management and treatment of osteoporosis is proposed.
    Revue médicale suisse 06/2012; 8(347):1417-21.
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    Skeletal Radiology 05/2012; · 1.74 Impact Factor
  • Skeletal Radiology 05/2012; · 1.74 Impact Factor
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    ABSTRACT: Magnetic resonance imaging (MRI) is an excellent imaging modality for soft tissues. Magnetization transfer (MT) imaging is an MRI technique that is sensitive to the bound protons of macromolecules and therefore can aid in the assessment of nerve damage. Measurements of the MT ratio (MTR), which provides an index of the MT effects in tissues, were performed in the wrist and foot of 5 volunteers. The MTR of foot (interdigital) nerves (22.2 ± 2.1%) was smaller than that of the median nerve (41.1 ± 1.4%). No difference was observed between MTR in muscles adjacent to foot nerves (46.0 ± 1.5%) and muscles adjacent to the median nerve (44.2 ± 1.9%). In this study we demonstrate the feasibility of measuring the MTR of foot nerves. The difference of MTR between median and foot nerves indicates a difference in structure/composition. The MTR of peripheral nerves may serve as a biomarker of nerve damage, collagen integrity, and demyelination.
    Muscle & Nerve 01/2012; 45(1):13-7. · 2.31 Impact Factor
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    François Luthi, Yan Eggel, Nicolas Theumann
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    ABSTRACT: Retinoids are effective and widely prescribed in the treatment of severe acne. However their use can be associated with numerous side effects. Some rare cases of premature epiphyseal closure were reported. We present the case of a sixteen-year-old soccer player referred for progressive anterior pain in both knees, evoking a patellar problem. Careful pharmacological questioning revealed use of isotretinoin for several months. MRI findings showed an irregularity of the growth plate and an important metaphyso-epiphyseal oedema, more noticeable in the left knee. Retinoid-induced premature epiphyseal closure was diagnosed. The treatment was stopped, with a resolution of pain within two months. After recovery a persisting small sequelar thumbprint-like growth plate lesion was observed on the control MRI. Retinoids induce an invasion of the growth plate by osteoclasts and a decrease in proteoglycans synthesis. It seems that the knee is the most affected joint. This complication being rare, a radiological follow-up of the young patients treated by retinoids is not proposed.
    Joint, bone, spine: revue du rhumatisme 12/2011; 79(3):314-6. · 2.25 Impact Factor
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    ABSTRACT: Osteochondritis dissecans (OCD) is a joint disorder that affects the articular cartilage and subchondral bone, most commonly at the knee. OCD of the sacroiliac joint is extremely rare. Management of OCD remains controversial, and surgery is often needed, especially when conservative treatment fails. We present a rare case of OCD involving the left sacroiliac joint successfully treated by percutaneous computed tomography-guided retrograde drilling and debridement.
    CardioVascular and Interventional Radiology 12/2011; 35(4):963-7. · 2.09 Impact Factor
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    ABSTRACT: The glomus tumor is a rare, benign, but painful vascular neoplasm arising from the neuromyoarterial glomus. Primary intraosseous glomus tumor is even rarer, with only about 20 cases reported in the literature so far, 5 of which involved the spine. Surgical resection is currently considered the treatment of choice. We herewith present an uncommon case of primary intraosseous spinal glomus tumor involving the right pedicle of the eleventh thoracic vertebra (T11). To our knowledge, this is the first case of primary intraosseous spinal glomus tumor successfully treated by percutaneous CT-guided radiofrequency ablation (RFA).
    Skeletal Radiology 11/2011; 41(4):467-72. · 1.74 Impact Factor
  • The Spine Journal 10/2011; 11(10). · 2.80 Impact Factor
  • Y. Eggel, F. Luthi, N. Theumann
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    ABSTRACT: Les rétinoïdes sont des médicaments efficaces dans le traitement de l’acné sévère. Leur utilisation peut cependant induire de nombreux effets secondaires. De rares épiphysiodèses prématurées ont été rapportées. Nous présentons le cas d’un jeune footballeur qui avait consulté pour des douleurs antérieures progressives. L’anamnèse médicamenteuse révélait l’utilisation d’isotrétinoïne. L’IRM montrait une irrégularité du cartilage de conjugaison et un important œdème métaphyso-épiphysaire, plus marqué au genou gauche. Le diagnostic d’épiphysiodèse induite par la prise de rétinoïde était retenu. Le traitement était stoppé, avec une résolution des symptômes en deux mois. Après guérison, une image en empreinte de pouce de la plaque de croissance persistait à l’IRM de contrôle. Les rétinoïdes provoquent une invasion de la plaque de conjugaison par des ostéoclastes et une diminution de synthèse de protéoglycans. Le genou semble l’articulation la plus touchée. Cette complication étant rare, un suivi radiologique des jeunes patients traités par rétinoïdes n’est cependant pas proposé.
    Revue du Rhumatisme 10/2011; 54.
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    ABSTRACT: Palmer previously proposed a classification system of triangular fibrocartilage complex (TFCC) injuries that proved to be useful in directing clinical management. However, dorsal peripheral tears (variants of class 1C) were not described and have rarely been reported in the literature since. We herewith present a rare case of bucket-handle tear of the TFCC. To our knowledge, this is the first case demonstrating partial separation of both the palmar and dorsal distal radioulnar ligaments (DRULs) from the articular disc. The particular wrist magnetic resonance (MR) arthrographic findings of this unusual complex peripheral TFCC tear (a variant of both class 1B and 1C) were nicely appreciated upon sagittal reformatted images.
    Skeletal Radiology 09/2011; 40(12):1617-21. · 1.74 Impact Factor
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    ABSTRACT: To assess the impact of axial traction during acquisition of direct magnetic resonance (MR) arthrography of the wrist with regard to joint space width and amount of contrast material between the opposing cartilage surfaces. Fifteen consecutive patients (12 male, mean age 38.1 years) were included in this Institutional Review Board-approved prospective study. Three-compartment wrist MR arthrographies were performed between October and December 2009 on a 3 T unit using a fat-suppressed T1-weighted isotropic high-resolution volumetric interpolated breathhold examination (VIBE) sequence in the coronal plane, with and without axial traction (3 kg). Two radiologists measured radiocarpal (radioscaphoid, radiolunate) and midcarpal (lunocapitate, hamatolunate) joint space widths, with and without traction, and assessed the amount of contrast material between the opposing cartilage surfaces using a three-point scale: 0 = absence, 1 = partial, 2 = complete. With traction, joint space width increased significantly at the radioscaphoid (Δ = 0.78 mm, P < 0.01), radiolunate (Δ = 0.18 mm, P < 0.01), and lunocapitate (Δ = 0.45 mm, P < 0.01) spaces, and both observers detected significantly more contrast material between the cartilage surfaces. At the hamatolunate space, the differences in joint space width (Δ = 0.14 mm, P = 0.54) and amount of contrast material were not significant. Direct wrist MR arthrography with axial traction of 3 kg increases joint space width at the radiocarpal and lunocapitate spaces, and prompts better coverage of the articular cartilage by the contrast material.
    Journal of Magnetic Resonance Imaging 07/2011; 34(1):239-44. · 2.57 Impact Factor

Publication Stats

794 Citations
223.19 Total Impact Points

Institutions

  • 1999–2013
    • University Hospital of Lausanne
      • Service de radiodiagnostic et radiologie interventionnelle
      Lausanne, Vaud, Switzerland
  • 2012
    • Clinique Bois-Cerf, Lausanne
      Lausanne, Vaud, Switzerland
  • 2011
    • Clinique romande de réadaptation
      Sitten, Valais, Switzerland
  • 2009
    • University of Lausanne
      • Department of Musculoskeletal Medicine
      Lausanne, VD, Switzerland
  • 2008
    • Université René Descartes - Paris 5
      • Faculté de Médecine
      Lutetia Parisorum, Île-de-France, France