Tomosynthesis in musculoskeletal pathology.

Tomosynthesis is an imaging technique that uses standard X-ray equipment with digital flat panel detectors to create tomographic images from very low-dose projections obtained at different angles. These images are parallel to the plane of the detector. Filtered back-projection or iterative reconstruction algorithms can be used to produce them. Iterative reconstruction used with a metal artifact reduction algorithm reduces metal artifacts, and therefore, improve image quality and in-depth spatial resolution. The radiation dose is lower compared to that of computed tomography and is two to three times the dose of a standard radiography. Tomosynthesis is intended for the analysis of high-contrast structures and especially for bones. It is superior to projection radiography when bone superimpositions are important or when metal structures hide regions of interest. The high in-plane resolution and its ability to perform exams in weight-bearing positioning are some of the main advantages of this technique. The impossible production of perpendicular multiplanar reconstruction and a limited contrast resolution are its main limitations. Tomosynthesis must be considered as an extension or an addition to standard radiography, as it can be performed in the same diagnostic step. The purpose of this article was to describe the principles, advantages and limitations, and current and future applications in musculoskeletal pathology of tomosynthesis.

Multimodality evaluation of musculoskeletal sarcoidosis: Imaging findings and literature review.

Whilst the detailed X-ray features of thoracic manifestations of sarcoidosis are now clearly defined and known by most radiologists, the same does not apply to osteoarticular and muscular features of the disease, which may however raise major diagnostic problems, either because they are the presenting features of the disease (7% of cases) or because they develop during its course. The bony lesions of sarcoid dactylitis (classical Perthes-Jüngling disease) are very characteristic and well known. Many other presentations of bone and bone marrow sarcoidosis may however raise major diagnostic difficulties, particularly uni- or multifocal osteolytic and sclerotic forms of the disease. The articular manifestations of sarcoidosis are difficult to distinguish from those of the other inflammatory and degenerative arthropathies. The muscular lesions in sarcoidosis are generally clinically silent and therefore often missed. MRI has shown them to be very common in active sarcoidosis. Acute forms carry a good prognosis whereas chronic lesions are a presenting feature of multi-organ sarcoidosis. Finally, clinicians should always think about the possibility of an iatrogenic origin for musculoskeletal abnormalities seen in sarcoidosis, particularly those related to corticosteroid therapy.

Closed loop obstruction: pictorial essay.

Closed loop obstruction occurs when a segment of bowel is incarcerated at two contiguous points. The diagnosis is based on multiple transitional zones. The incarcerated loops appear in U or C form or present a radial layout around the location of the obstruction. It's very important to specify the type of obstruction because, in patients with simple bowel obstruction, a conservative approach is often advised. On the other hand, a closed loop obstruction immediately requires a surgical approach because of its high morbidity and the risk of death in case of a late diagnosis.

[Combined pulmonary fibrosis and emphysema: the natural history of the disease. The chronological evolution of clinical features, respiratory function and the CT scan]. / Syndrome emphysème - fibrose pulmonaire : histoire naturelle de la maladie. Évolution chronologique clinique, fonctionnelle respiratoire et scanographique.

INTRODUCTION: The syndrome of combined basal pulmonary fibrosis and apical emphysema (CPFE) is characterised by severe dyspnoea not fully explained by pulmonary function tests that show subnormal lung volumes and expiratory flows while CT imaging reveals varying degrees of emphysema and interstitial fibrosis. CASE REPORT: A man presented with chronic obstructive pulmonary disease associated with severe emphysema. Airflow obstruction was associated with early over-inflation. Five years later he developed interstitial fibrosis with CT appearances compatible with non-specific interstitial pneumonitis. Simultaneously, the decreased expiratory flows due to emphysema had become normal and the pulmonary distension had resolved. CONCLUSION: When CPFE develops, the reduced expiratory flows and thoracic distension due to emphysema can resolve. These changes may be explained by the late development of interstitial changes, which balance the functional consequences of emphysema by an increase in elastic recoil and reduction in volume. This is the first case report that describes the evolutionary profile in a single patient. It reinforces the pathophysiological hypothesis that explains the normal pulmonary volumes and expiratory flows in CPFE.

Aorto-enteric fistulas: a physiopathological approach and computed tomography diagnosis.

Infection of an abdominal aortic prosthesis with an enteroprosthetic fistula is a very serious, life-threatening complication, leading sometimes to severe functional consequences, the most serious being amputation. Since the symptoms, if there are any, are often rather non-specific, diagnosis is frequently difficult and has always to be based on a whole series of justifications. Early diagnosis is essential and this fistula should be the first possibility considered in a patient with an abdominal aortic prosthesis who is presenting rectorrhagia or melaena (even if only to a slight degree), sepsis and/or abdominal pain. Although rare, the clinical existence of hypertrophic osteoarthropathy may assist diagnosis. A CT scan is the examination of choice, the criteria providing evidence of a fistula being the presence of gaseous images in a periprosthetic fluid collection, thickening and/or retraction of the intestinal walls in contact, the existence of a false aneurysm, and finally, very rarely, extravasation of contrast agent into the intestinal lumen. The differential diagnoses that may mimic a fistula need to be well known, and can include retroperitoneal fibrosis, an infectious aneurysm, inflammatory or infectious aortitis, and above all, a 'simple' prosthesis infection without fistulisation.

[Peritoneal parasitic teratoma and chemical dermoid peritonitis]. / Tératomes parasitiques péritonéaux et péritonites chimiques dermoïdes.

Chemical peritonitis occurs following intraperitoneal rupture of a mature ovarian dermoid. Rupture may be acute and spontaneous, typically during pregnancy, or iatrogenic. Low grade ruptures lead to parasitic peritoneal dermoid cysts, usually involving the greater omentum, cul-de-sac of Douglas and perihepatic region. Radiologists should be familiar with their appearance to correctly diagnose the condition and not mistake the disease for peritoneal carcinomatosis.

[Impact of whole body magnetic resonance imaging (MRI) in the management of melanoma patients, in comparison with positron emission tomography/computed tomography (TEP/CT) and CT]. / Apport de l'imagerie en résonance magnétique (IRM) du corps entier dans la prise en charge du mélanome : comparaison avec la tomoscintigraphie par émission de positons couplée à la tomodensitométrie (TEP-TDM) et à la TDM seule.

BACKGROUND: PET/CT has proven extremely useful in the management of melanoma patients, with great sensitivity (Se), but it tends to give false-positive results. Whole-body MRI (wb-MRI) is a new method that has made considerable progress. STUDY AIMS: The aim of this study was to assess the Se and specificity (Sp) of wb-MRI with a diffusion sequence for detecting melanoma metastasis compared to PET/CT. METHODS: This was a prospective study, including patients at any AJCC (American Joint Committee on Cancer) stage of melanoma. PET/CT, wb-MRI and CT, including the brain, were performed on the same day. For each of the three exams, the number of lesions per patient was counted. The treatments proposed by the doctor immediately after PET/CT and then MRI were compared. RESULTS: Forty patients were included and a total of 72 metastases were noted. CT detected 53 of these metastases (Se 80%, Sp 95%), while PET/CT detected 53 metastases, with four false-positive (Se 74%, Sp 89%) and Wb-MRI detected 59, with two false-positive (Se 83%, Sp 96%). The sensitivity of MRI was distinctly superior to PET/CT for both hepatic and pulmonary lesions. The treatment proposed after PET/CT and MRI differed in three cases: one patient was falsely reclassified by MRI (AJCC IV instead of IIB) while two others were falsely reclassified by PET/CT (AJCC IV instead of IB and IIIC). Exclusively whole-body scan influenced the treatment of four patients (10%). CONCLUSION: Wb-MRI with diffusion sequence, which is less costly than PET/CT and is also non-radioactive, could play an important role in the detection of metastases in melanoma patients.

Additional benefit of procalcitonin to C-reactive protein to assess disease activity and severity in Crohn's disease.

BACKGROUND: Serum procalcitonin level may reflect non-infectious inflammation. AIM: To assess the correlation of serum procalcitonin level with clinical, biological, endoscopic and radiological markers of disease activity in inflammatory bowel diseases (IBD), and to evaluate the additional diagnostic benefit of measuring serum procalcitonin level to that of C-reactive protein (CRP) for disease activity appraisal. METHODS: We performed a prospective observational study. Spearman's rank correlation and receiver operating characteristic analysis were used to evaluate correlation and diagnostic accuracy respectively. RESULTS: In Crohn's disease (CD) (n = 30), serum procalcitonin level was strongly correlated with clinical, biological, endoscopic and radiological disease activity markers. In CD, the serum procalcitonin level >0.14 µg/L demonstrated a high accuracy for detecting severe disease (Sensitivity = 100%; Specificity = 96%; AUROC = 0.963; P = 0.0001). The diagnostic accuracy of the 'serum procalcitonin level-CRP strategy' (CRP >5 mg/L and serum procalcitonin level >0.05 µg/L) was significantly superior to that of CRP alone for diagnosing severe CD (AUROC = 0.783 vs. 0.674; P = 0.01). In ulcerative colitis (UC) (n = 27), serum procalcitonin level was correlated with CRP and with endoscopic and radiological disease activity markers. CONCLUSIONS: In CD, the serum procalcitonin level was correlated with all disease activity markers and a cut-off of 0.14 µg/L could distinguish severe forms of the disease. The 'serum procalcitonin level-CRP strategy' was superior to CRP alone for diagnosing active or severe CD.

[Liver calcifications in adults: the KUB stars are too frequently neglected in the CT era]. / Calcifications hépatiques de l'adulte: les stars de l'ASP trop souvent négligées à l'ère du scanner.

Liver calcifications have been extensively described on plain radiographs, either from KUB or angiography examinations. On the other hand, their characteristics are seldom reported on cross-sectional imaging: they are frequently considered as non-specific compared to multiple other imaging features. However, clinical practice demonstrates that in specific situations (such as parasitic infections and calcified metastases), the presence of calcifications may be a determining factor in avoiding misdiagnosis with potential deleterious effects to the patient. Both CT and US can detect a large number of "benign" calcifications without associated focal lesion and knowledge of their imaging features is useful to avoid unnecessary additional imaging work-up. A review of the literature and a series of 100 cases of liver calcifications on CT are presented to review the imaging features of calcified liver lesions and isolated liver calcifications without associated focal lesion.

[Do all cryptogenic organizing pneumonias require lung biopsy and steroid treatment?]. / Pneumopathie organisée cryptogénique : biopsie et corticoïdes sont-ils constamment utiles ?

INTRODUCTION: Diagnostic guidelines recommend a lung biopsy to make the diagnosis of cryptogenic organizing pneumonia (COP). However, in some cases, in the presence of a typical clinical picture, the diagnosis can be made without histological proof: the combination of a "reversed halo sign" and migratory areas of patchy alveolar consolidation on the CT-scan is strongly suggestive. Steroids are the recommended treatment, but relapses and complications of steroids occur frequently whereas the morbidity of COP is usually low and the evolution is often the same with or without treatment. CASE REPORT: We report the case of a 51 year old woman with mild COP. The diagnosis was made according to the clinico-radiological criteria that we propose, without any formal histological proof. Treatment consisted of a short course of steroids, which led to spectacular clinical and radiological improvement but was withdrawn due to poor tolerance. The patient refused further treatment but clinical progress was favourable. After a follow-up period of 2.5 years a CT-scan showed evidence of a radiological relapse but the patient remained asymptomatic. CONCLUSION: In this article, we do not attempt to prove that lung biopsy and steroid treatment are unnecessary in the management of COP, but we would like to propose that, in some situations with the coexistence of a "reversed halo sign" and migratory areas of patchy consolidation on the CT-scan, in the context of a typical clinical presentation and mild symptoms, the usefulness of lung biopsy and steroid treatment is debatable.