Standardized reporting of spine and sacroiliac joints in axial spondyloarthritis MRI: from the ESSR-Arthritis Subcommittee.

OBJECTIVES: Apply a modified Delphi-based approach and produce a practical, radiology-specific set of definitions for interpretation and standardization of the multiple MRI findings in axial spondyloarthritis (ax-SpA), specifically to aid the general radiologist with a musculoskeletal interest, working with gold standard basic MRI protocols. MATERIALS AND METHODS: We report the results of a modified Delphi-based consensus of 35 experts from 13 countries in the Arthritis Subcommittee of the European Society of Musculoskeletal Radiology (ESSR). Seventeen definitions were created (i.e., nine for the spine and eight for the sacroiliac joint) and two Delphi rounds were conducted on an electronic database, collated and revised by the project leader with agreement. Group leads were appointed for each definition following the first round. Final definitions included only those that reached a consensus > 80%; if > 50% agreed on exclusion consensus, definitions were excluded. Final results have been shared during the Arthritis meeting at the Annual ESSR Congress. RESULTS: Fourteen definitions, eight for the spine and six for the sacroiliac joint were agreed for standardized reporting. Andersson's, anterior corner sclerotic and costovertebral joint inflammatory lesions of the spine, with active and non-active erosions, and fat metaplasia of the sacroiliac joint reaching the highest consensus (≥ 95%). More than 50% of the experts agreed to exclude joint space inflammation in the sacroiliac joint and tissue backfill. Syndesmophytes reached 76% agreement. CONCLUSIONS: Agreed definitions by expert radiologists using a modified Delphi process, should allow standardized actionable radiology reports and clarity in reporting terminology of ax-SpA. CLINICAL RELEVANCE STATEMENT: The proposed definitions will support reporting from musculoskeletal and general radiologists working with gold-standard basic MRI, improve confidence in lesion assessment, and standardize terminology to provide actionable reports on MRI in patients with ax-SpA. KEY POINTS: Experts applied a modified Delphi method to optimize the definitions of MRI findings of ax-SpA. After two Delphi rounds and one in-person meeting, fourteen definitions reached the agreement threshold. These consensus-based definitions will aid in actionable reporting specifically for the general radiologist with a musculoskeletal interest.

Renal Failure: A Modern Semiology for an Old Disease.

Chronic kidney disease (CKD) is a complex systemic disease that induces mineral metabolic dysfunction leading to bone fragility and tissue calcifications. Bone abnormalities in CKD can include increased bone turnover and resorption due to secondary hyperparathyroidism, decreased bone turnover and bone formation, defective bone mineralization, or a mixed pattern of these abnormalities. Other features of musculoskeletal involvement include synovial, tendon, and ligament thickening due to ß2-microglobulin amyloidosis, soft tissue masses, or axial and peripheral arthropathies. The accurate assessment of bone involvement in early-stage CKD is crucial for the success of therapeutic interventions. We summarize the key semiologic features of bone abnormalities in CKD and review musculoskeletal complications as depicted by conventional radiography, computed tomography, magnetic resonance, and ultrasound imaging. We also discuss different experimental diagnostic approaches developed for the purpose of identifying changes in bone quality and structure in early-stage CKD.

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

PURPOSE: 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. MATERIALS AND METHODS: Eighty volunteers (40 men; 40 women; ages: 20-60 years; divided into four consecutive groups) underwent acetabulum, femoral head, femoral neck, greater trochanter, and diaphysis localized (1) H MR spectroscopy. FC values of each anatomical site were obtained according to the following formula: Fat content = CH2 /(CH2 + Water)*100. To assess bone marrow conversion, a spectroscopic conversion index (SCI) was calculated as FC neck/FC greater trochanter. RESULTS: FC values showed a gradient as follows: greater trochanter > femoral head > femoral neck > diaphysis > acetabulum in every age group both in men and in women. SCI increased with age both in men and women, showing lower values in women for every age group. CONCLUSION: We obtained normal spectroscopic FC values from different areas of the hip, according to age and sex. These values may be used as reference values to evaluate, by the means of (1) H MR spectroscopy, pathological conditions affecting hip bone marrow.

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.

Reproducibility of 1H MR spectroscopy of hip bone marrow at 3 Tesla.

PURPOSE: To assess the reproducibility of fat content (FC) values in five different anatomical areas of proximal femur by the means of (1)H 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. MATERIALS AND METHODS: Thirty-three volunteers underwent unilateral (1)H MR spectroscopy of the hip. From 1 to 4 weeks later, they repeat the MR examination of the same hip to assess the reproducibility of the technique. Fifteen other volunteers underwent a bilateral (1)H MR hip spectroscopy to compare right and left side FC values. RESULTS: The reproducibility of (1)H MR spectroscopy was high in all the anatomic areas considered, ranging from 0.90 to 0.98. No statistically significant difference was found when the fat content values on the right side were compared to those on the left side. (P > 0.16). CONCLUSION: The 3 Tesla (1)H MR spectroscopy of hip bone marrow permitted highly reproducible fat content values in all the five anatomic areas examined. No statistical significant difference existed when comparing fat content values of the right side to those of the left side in the same individual.

Anatomical study of the pisotriquetral joint ligaments using ultrasonography.

OBJECTIVE: The 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 MATERIALS: This 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. RESULTS: At 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. CONCLUSIONS: The 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.

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.

Assessment of lobar perfusion in smokers according to the presence and severity of emphysema: preliminary experience with dual-energy CT angiography.

The purpose of the study was to assess pulmonary perfusion on a lobar level in smokers using dual-energy computed tomography (CT). Forty-seven smokers and ten non-smokers underwent a dual-energy multi-detector CT angiogram of the chest that allowed automatic quantification of emphysema and determination of the iodine content at the level of the microcirculation (i.e. "perfusion imaging"). Emphysema was present in 37 smokers and absent in ten smokers. Smokers with an upper lobe predominance of emphysema (n = 8) had: (1) significantly lower attenuation enhancement values in the upper lobes compared with smokers without emphysema; (2) the lobes with the most severe emphysematous changes had a statistically significantly higher percentage of emphysema (p = 0.0001) and lower mean attenuation enhancement values (p = 0.0001) than the ipsilateral lobes with less severe emphysema, matching parenchymal destruction; (3) a correlation was found between the difference in percentage of emphysema between the upper and lower lobes and the difference in attenuation attenuation enhancement values in the corresponding lobes (p = 0.0355; r = -0.54). Regional alterations of lung perfusion can be depicted by dual-energy CT in smokers with predominant emphysema.

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.

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.

Screening for coronary artery disease in respiratory patients: comparison of single- and dual-source CT in patients with a heart rate above 70 bpm.

To evaluate the assessibility of coronary arteries in respiratory patients with high heart rates. This study was based on the comparative analysis of two paired populations of 54 patients with a heart rate >70 bpm evaluated with dual-source (group 1) and single-source (group 2) CT. The mean heart rate was 89.1 bpm in group 1 and 86.7 bpm in group 2 (P=0.26). The mean number of assessable segments per patient was significantly higher in group 1 compared to group 2 (P

Lung perfusion with dual-energy multidetector-row CT (MDCT): feasibility for the evaluation of acute pulmonary embolism in 117 consecutive patients.

RATIONALE AND OBJECTIVES: To investigate the accuracy of dual-energy computed tomography in the depiction of perfusion defects in patients with acute pulmonary embolism (PE). MATERIALS AND METHODS: One hundred seventeen consecutive patients with clinical suspicion of acute PE underwent dual-energy multidetector computed tomographic (CT) angiography of the chest with a standard injection protocol. Two radiologists evaluated, by consensus, the presence of endoluminal clots on (1) transverse "diagnostic" scans (contiguous 1-mm-thick averaged images from tubes A and B) and (2) lung perfusion scans. RESULTS: Seventeen patients showed CT features of acute PE, with the depiction of 75 clots within the lobar (n = 15), segmental (n = 43) and subsegmental (n = 17) pulmonary arteries. A total of 17 clots were identified as complete filling defects (ie, obstructive clots), located within segmental (12 of 17) and subsegmental (5 of 17) arteries. Fourteen of the 17 obstructive clots were seen with the concurrent presence of corresponding perfusion defects, whereas cardiac motion and/or contrast-induced artifacts precluded the confident recognition of perfusion abnormalities in the remaining two segments and one subsegment. Four subsegmental perfusion defects were depicted without the visualization of endoluminal thrombi within the corresponding arteries. Perfusion defects were identified beyond five nonobstructive clots. CONCLUSION: Simultaneous information on the presence of endoluminal thrombus and lung perfusion impairment can be obtained with dual-energy computed tomography.

Thoracic applications of dual-source CT technology.

Among the various imaging modalities available, CT has remained over time the core imaging technique for the evaluation of respiratory disorders. The recent advent of dual-source CT offers innovative approaches to investigate thoracic diseases, based on the use of one or two tubes as well as single or dual energy to scan the entire thorax. Two major options can be used in clinical practice with promising results. Dual source, single-energy scanning allows scanning of the entire thorax with ultra-high temporal resolution which opens the field of integrated cardiothoracic imaging without ECG gating as well as optimized evaluation of pediatric and adult patients with limited ability to cooperate. Dual-source, dual-energy acquisitions represent another very innovative means of investigating respiratory disorders, adding tissue characterization and functional analysis to morphological evaluation. The purpose of this review article is to provide results on preliminary experiences with the above-mentioned scanning conditions with dual-source CT and to envisage potential forthcoming applications in the field of thoracic imaging.