Vittorio Pansini

Use of Tomosynthesis for Erosion Evaluation in Rheumatoid Arthritic Hands and Wrists

PURPOSE To compare tomosynthesis with radiography for the detection of hand and wrist bone erosions in patients with rheumatoid arthritis (RA), using multidetector computed tomography (CT) as the reference method. MATERIALS AND METHODS The study was approved by the local ethics committee, and written consent was obtained from all patients. From December 2008 to April 2009, 30 consecutive patients with RA were included in this prospective study. They underwent radiography, tomosynthesis, and CT of the most symptomatic hand and wrist on the same day. Two radiologists and one rheumatologist independently read images from the three imaging modalities. RESULTS A total of 232 erosions were detected with CT, while 199 and 140 erosions, respectively, were detected with tomosynthesis and radiography. More erosions were revealed with CT than with tomosynthesis and radiography (P < .0001); significantly more erosions were shown with tomosynthesis than with radiography (P < .0001). With CT as the reference method for bone erosions, the overall sensitivity, specificity, and accuracy of tomosynthesis were, respectively, 77.6%, 89.9%, and 83.1%. The corresponding values for radiography were 53.9%, 92%, and 70.9%. The sensitivity of each reader increased by roughly 20% with use of tomosynthesis. CONCLUSION The depiction of bone erosions of the hands and wrists is significantly greater with tomosynthesis than with radiography.

Bone marrow fat.

Bone marrow fat (BMF) results from an accumulation of fat cells within the bone marrow. Fat is not a simple filling tissue but is now considered as an actor within bone microenvironment. BMF is not comparable to other fat depots, as in subcutaneous or visceral tissues. Recent studies on bone marrow adipocytes have shown that they do not appear only as storage cells, but also as cells secreting adipokines, like leptin and adiponectin. Moreover bone marrow adipocytes share the same precursor with osteoblasts, the mesenchymal stem cell. It is now well established that high BMF is associated with weak bone mass in osteoporosis, especially during aging and anorexia nervosa. But numerous questions remain discussed: what is the precise phenotype of bone marrow adipocytes? What is the real function of BMF, and how does bone marrow adipocyte act on its environment? Is the increase of BMF during osteoporosis responsible for bone loss? Is BMF involved in other diseases? How to measure BMF in humans? A better understanding of BMF could allow to obtain new diagnostic tools for osteoporosis management, and could open major therapeutic perspectives.

3 Tesla 1H MR spectroscopy of hip bone marrow in a healthy population, assessment of normal fat content values and influence of age and sex

To evaluate in a healthy population normal spectroscopic fat content (FC) values of the hip bone marrow and to assess the influence of age and sex on bone marrow conversion.

Diffusion Tensor Imaging in Musculoskeletal Disorders

Diffusion tensor (DT) imaging is an emerging magnetic resonance (MR) imaging technique for evaluating the microstructure of well-organized biologic tissues such as muscles and nerves. DT imaging provides information about tissue microstructure by producing three-dimensional maps of water molecule movements. The two main parameters of measurement at DT imaging, fractional anisotropy and the apparent diffusion coefficient, allow quantitation of architectural changes occurring in tissue. These parameters are modified in the presence of cervical spondylotic myelopathy, cervical spine trauma, carpal tunnel syndrome, lumbar nerve compression, peripheral nerve tumors, and muscle ischemia. Their alteration may be observed at DT imaging even when no abnormality is seen at conventional MR imaging, a fact that suggests that DT imaging allows the detection of abnormalities at an earlier stage of injury. Experimental studies in animals have shown that DT imaging consistently allows identification of pathophysiologic alterations in tissue that correlate with histologic findings. Tractographic images accurately depict both normal and abnormal diffusion in anatomic structures such as the thigh and pelvic muscles, cervical spine, and lumbar nerves. Patients with chronic diseases also may benefit from follow-up evaluation with DT imaging, although DT imaging sequences must be further adapted to improve the evaluation of specific anatomic regions by reducing artifacts, optimizing spatial resolution, and minimizing acquisition time. Given its proven potential for use in identifying abnormalities that are otherwise identifiable only with electrophysiologic and histopathologic studies, and with future technical improvements, DT imaging could soon become a standard method for early diagnosis, management, and follow-up of disease in the spine, muscles, and peripheral nerves.

Comparison of two-dimensional fast Raman imaging versus point-by-point acquisition mode for human bone characterization.

Recent technical developments gave rise to a new technology for two-dimensional fast Raman imaging: the DuoScan averaging mode (DS-Avg). This technology allows the acquisition of a Raman spectrum over a rastered macro spot. The aim of this study was to evaluate the interest of the DS-Avg applied on trabecular human bone. The evaluation was based on the comparison of the DS-Avg versus the point-by-point mapping mode in real usage conditions. The signal-to-noise ratio, the spectral difference, and the physicochemical parameters were estimated for comparison of the efficiency of both modes. Principal component analysis was performed to explore the capacity of both modes to detect compositional variations. Results showed that the DS-Avg spectrum was equivalent to the average spectrum of individual spectra acquired with the point-by-point mode for the same sample area. The physicochemical parameters can be also determined from DS-Avg acquisition. The DS-Avg combined with an objective ×50 allows a drastic decrease of the acquisition time, but the information about the micrometric composition is lost. The combination of the DS-Avg with an objective ×100 is a good compromise between acquisition time and resolution. The DS-Avg is a useful technology for imaging mineral and organic phases of bones and for assessing their spatial distribution on large samples. The point-by-point imaging mode is more appropriate to assess the heterogeneous composition of bone within the micrometer scale. For the first time, this study compares the DuoScan averaging mode to the point-by-point imaging mode on a trabecular human bone.

Anatomical study of the pisotriquetral joint ligaments using ultrasonography

ObjectiveThe aim of this study was to demonstrate that ultrasonography may allow a precise assessment of the primary stabilizers of pisotriquetral joint (pisohamate, pisometacarpal, and ulnar pisotriquetral ligaments).Methods and materialsThis study was initially undertaken in eight cadavers. Metal markers were placed in the ligaments using ultrasonographic guidance, followed by the dissection of the wrists. High-resolution ultrasonography was then performed in 15 volunteers (30 wrists) for the analysis of the presence, appearance, and thickness of the ligaments.ResultsAt dissection, the metal markers were located in the ligaments or immediately adjacent to them, confirming that they were correctly depicted using ultrasonography. The three ligaments could also be identified in each volunteer. The optimal positioning of the probe and the dynamic maneuvers of the wrist allowing the strain of these ligaments could be defined. No significant changes in the appearance and thickness of the ligaments could be observed.ConclusionsThe three ligaments stabilizing the pisotriquetral joint can be identified using ultrasonography. Further studies are now required to know whether this knowledge may be useful in the assessment of pain involving the ulnar part of the wrist.

Reproducibility of 1H MR spectroscopy of hip bone marrow at 3 tesla

To assess the reproducibility of fat content (FC) values in five different anatomical areas of proximal femur by the means of 1H 3 Tesla MR spectroscopy and to evaluate if any statistical difference exists when comparing right side to left side FC values in the same individual.

Entrapment Neuropathies of the Shoulder

Entrapment neuropathies are a rare but presumably underdiagnosed cause of shoulder pain and painful instability. Radiologists must be aware of the clinical presentations and imaging features of these neuropathies because they may be the first to suggest these diagnoses. In this article, instead of a classical nerve-by-nerve approach, entrapment neuropathies are deciphered according to the clinical situation: which anatomic structures may be involved, how to explore them, which imaging abnormalities can be expected, how to manage differential diagnoses, and which therapeutic options can be considered.

Pisotriquetral joint disorders: an under-recognized cause of ulnar side wrist pain

Pisotriquetral joint disorders are often under-recognized in routine clinical practice. They nevertheless represent a significant cause of ulnar side wrist pain. The aim of this article is to present the main disorders of this joint and discuss the different imaging modalities that can be useful for its assessment.