[Chronic nonbacterial osteomyelitis : Imaging and differential diagnoses]. / Chronische nichtbakterielle Osteomyelitis : Bildgebung und Differenzialdiagnosen.

Chronic nonbacterial osteomyelitis (CNO) is an autoinflammatory bone disease in childhood and adolescence with a preference for the female gender. It is manifested with multiple osseous lesions, with a predilection for the metaphyseal end zones of the long bones of the lower extremities. These bone lesions usually occur multifocally, can recur and develop a different appearance depending on the bone structure affected. Patients present with a longer disease history, changing clinical symptoms and unspecific paraclinical signs. Magnetic resonance imaging (MRI) is the imaging of choice and particularly as a whole body examination can speed up the diagnosis and is an important component of follow-up controls. Differential diagnoses include numerous inflammatory, benign and malignant bone diseases. Therefore, it is essential to know the diagnosis of CNO and to take it into consideration in cases of an unclear inflammatory bone process in young patients.

Magnetic Resonance imaging analysis of liver fibrosis and inflammation: overwhelming gray zones restrict clinical use.

Magnetic resonance (MR) identification and grading of subjects with liver fibrosis and inflammation represents a clinical challenge. MR elastography plays a well-defined role in fibrosis estimation, but its use is not widely available in clinical settings. Given that liver MR is becoming the reference standard for fat and iron quantitation, there is a need to clarify whether there is any role for MR imaging in the concomitant evaluation of fibrosis and inflammation in this setting. This review summarizes the diagnostic estimations of different MR imaging parameters obtained from conventional non-contrast-enhanced multiple b values diffusion-weighted acquisitions, variable flip angles T1 relaxation maps and STIR images. Although some derived parameters have shown a significant correlation to histological scores, a small magnitude of effect with wide overlap across severity grades is the rule. Contrary to fat and iron quantification, the low precision and reproducibility of MR imaging metrics limits its clinical relevance in fibrosis and inflammation assessment. In a sequential clinical approach combining different methodologies, MR imaging has no applicability for ruling-out and low accuracy for ruling-in advanced fibrosis. Thereby, MR elastography remains as the only image method with high diagnostic accuracy for the detection of advanced fibrosis. Until date, inflammation remains in a gray zone where biopsy cannot be replaced, and further investigations are needed. The present review offers an in-depth discuss of the MR imaging diagnostic performance for the evaluation of liver fibrosis and inflammation, highlighting the need for scientific improvements.

MRI-detected bone marrow changes within 3 weeks after initiation of high-dose corticosteroid therapy: a possible change preceding the subsequent appearance of low-intensity band in femoral head osteonecrosis.

Osteonecrosis of the femoral head is considered to occur early during the course of corticosteroid treatment. However, it remains unclear exactly how early it can develop after initiation of corticosteroid treatment. We report a case of osteonecrosis of the femoral head in which abnormal findings were observed on short-tau inversion recovery (STIR) sequence image performed 2 weeks and 4 days after initiation of high-dose corticosteroid therapy. A 45-year-old man with hemophagocytic syndrome was started on prednisolone, with a maximum dose of 40 mg/day. On day 13 after initiation of this corticosteroid therapy, he transiently experienced left hip pain with no apparent cause. STIR sequence image 5 days after the onset of pain revealed high-intensity bone marrow lesions at the femoral neck of both hips. At 3 months after initiation of corticosteroid therapy, T1-weighted magnetic resonance imaging revealed concave-shaped low-intensity bands, which corresponded to the preceding high-intensity lesions on both hips. Because of the subsequent progression to collapse of the left femoral head, he underwent prosthetic replacement surgery. The high-intensity lesions on STIR sequence image indicate the possibility that osteonecrosis can occur within 3 weeks after initiation of high-dose corticosteroid therapy.

MRI investigation of radiating pain in the lower limbs: value of an additional sequence dedicated to the lumbosacral plexus and pelvic girdle.

OBJECTIVE: In some cases, sciatica-like symptoms radiating through the buttock, anterior thigh, or leg result from spinal root compression in an extraspinal location or from injury to the pelvic girdle. It has been suggested that adding a coronal STIR sequence dedicated to the lumbosacral plexus and pelvis to the routine MRI protocol can provide a good depiction of disorders of this type. MATERIALS AND METHODS: Two hundred nine patients with sciatica-like symptoms of suspected lumbar origin were included in the study. Disorders responsible for symptoms involving extraspinal compression of the lumbosacral plexus or pelvic girdle were retrospectively noted and correlated with age, sex, location of pain, referring physician, presence of discoradicular impingement liable to explain symptoms, and history of neoplasia. RESULTS: An extraspinal cause of symptoms was depicted in 12 cases (5.7%), including three cases of extraspinal compression and nine differential diagnoses in the pelvic region. Prevalence of an extraspinal cause of pain was significantly correlated with the absence of discoradicular impingement in the spine (p=0.046). A higher prevalence of extraspinal compression of the lumbosacral plexus (p=0.029) was seen in patients 60 years old or older, whereas no other feature was statistically associated with an extraspinal cause of pain. CONCLUSION: Because of its short acquisition time and subsequent low cost, the additional coronal STIR sequence should be performed in the routine MRI investigation of sciatica-like symptoms when no discoradicular impingement is seen in the spine to depict an extraspinal cause of symptoms.