Imaging spectrum of Bing-Neel syndrome: how can a radiologist recognise this rare neurological complication of Waldenström's macroglobulinemia?

OBJECTIVES: Bing-Neel syndrome (BNS) is a rare neurological complication of Waldenström's macroglobulinemia. The aim of this study is to describe the spectrum of radiological manifestations of this syndrome and their prevalence in order to facilitate its early diagnosis. METHODS: Twenty-four patients with BNS were diagnosed between 1994 and 2016 in eight centres in France. We retrospectively examined the medical records of these patients as well as the corresponding literature, focusing on imaging studies. Recorded data were statistically analysed and radiological findings described. RESULTS: The mean age of our patients was 62.4 years (35-80 years). The vast majority of patients were men, with a male to female ratio of 9:1. Findings included parenchymal or meningeal involvement or both. The most common finding was leptomeningeal infiltration, either intracranial or spinal, with a prevalence reaching 70.8%. Dural involvement was present in 37.5% of patients. In 41.7% (10/24) of patients, there was parenchymal involvement with a higher prevalence of brain comparing to medullar involvement (33.3% and 23.1% respectively). High T2 signal of the parenchyma was identified in 41.7% of patients and high signal in diffusion was evident in 25% of them. Intraorbital or periorbital involvement was also detected in four cases. A proposition regarding the appropriate imaging protocol completed our study. CONCLUSION: BNS's diagnosis remains challenging. Central nervous system MRI findings in the setting of known or suspected Waldenström's macroglobulinemia appear to be highly suggestive of BNS and appropriate imaging protocols should be implemented for their depiction. KEY POINTS: • Diagnosis of Bing-Neel syndrome (BNS) remains challenging and recent expert recommendations include MRI in the diagnostic criteria for the syndrome. • The most common radiological manifestations of BNS are leptomeningeal/dural infiltration or parenchymal involvement of brain or spinal cord, but many atypical forms may exist with various presentations. • Appropriate imaging protocol for BNS should include enhanced MRI studies of both brain and spine.

Three-dimensional MR imaging of the brachial plexus.

Pathologic conditions of the brachial plexus often result in serious and disabling complications. With the increasing availability and use of new and powerful MRI sequences and coils, understanding and assessment of the complex anatomy and pathology of the brachial plexus have been greatly facilitated. These new technical developments have led to an improved assessment of brachial plexus lesions, thereby improving patient care. In this article we describe various MRI techniques for the evaluation of the brachial plexus obtained at 1.5 T and 3 T, and we explain differences and similarities between sequences and protocols performed on MRI equipment from different vendors. The main characteristics of pathologic conditions affecting the brachial plexus are discussed and illustrated, as well as their differential diagnoses, with an emphasis on key imaging findings and relevance for patient management. Pitfalls related to suboptimal technique and image interpretation are also addressed.

A new method of real-time skin dose visualization. Clinical evaluation of fluoroscopically guided interventions.

INTRODUCTION: We have conducted a prospective study to clinically evaluate a new radiation dose observing tool that displays patient's peak skin dose (PSD) map in real time. METHODS: The skin dose map (SDM) prototype quantifies the air kerma based on exposure parameters from the X-ray system. The accuracy of this prototype was evaluated with radiochromic films, which were used as a mean for PSD measurement. RESULTS: The SDM is a reliable tool that provides an accurate PSD estimation and location. CONCLUSION: SDM also has many advantages over the radiochromic films, such as real-time dose evaluation and easy access to critical operational parameters for physicians and technicians.

Dual-energy CT in vertebral compression fractures: performance of visual and quantitative analysis for bone marrow edema demonstration with comparison to MRI.

OBJECTIVE: To prospectively evaluate the performance of virtual non-calcium (VNC) dual-energy CT (DECT) images for the demonstration of trauma-related abnormal marrow attenuation in collapsed and non-collapsed vertebral compression fractures (VCF) with MRI as a reference standard. MATERIALS AND METHODS: Twenty patients presenting with non-tumoral VCF were consecutively and prospectively included in this IRB-approved study, and underwent MRI and DECT of the spine. MR examination served as a reference standard. Two independent readers visually evaluated all vertebrae for abnormal marrow attenuation ("CT edema") on VNC DECT images; specificity, sensitivity, predictive values, intra and inter-observer agreements were calculated. A last reader performed a quantitative evaluation of CT numbers; cut-off values were calculated using ROC analysis. RESULTS: In the visual analysis, VNC DECT images had an overall sensitivity of 84%, specificity of 97%, and accuracy of 95%, intra- and inter-observer agreements ranged from k = 0.74 to k = 0.90. CT numbers were significantly different between vertebrae with edema on MR and those without (p < 0.0001). Cut-off values provided sensitivity of 85% (77%) and specificity of 82% (74%) for "CT edema" on thoracic (lumbar) vertebrae. CONCLUSIONS: VNC DECT images allowed an accurate demonstration of trauma-related abnormal attenuation in VCF, revealing the acute nature of the fracture, on both visual and quantitative evaluation.

Imaging evaluation of inflammation in the musculoskeletal system: current concepts and perspectives.

Inflammation is the non-specific stereotyped reaction of the musculoskeletal system to various types of aggression, such as infection, tumor, autoimmune diseases, or trauma. Precise evaluation and, increasingly, reliable quantification of inflammation are now key factors for optimal patient management, as targeted therapies (e.g., anti-angiogenesis, anti-macrophages, anti-cytokines) are emerging as everyday drugs. In current practice, inflammation is evaluated mostly using MRI and US on the basis of its non-specific extracellular component due to the increased volume of free water. Inflamed tissue is described as areas of low T1 signal and high T2 signal on magnetic resonance imaging or as hypoechogenic areas on ultrasound imaging, and the evaluation of the increased tissue vascularity can be performed using gadolinium-enhanced MRI or power Doppler US. Emerging new imaging tools, regrouped under the label "cellular and molecular imaging" and defined as the in vivo characterization and measurement of biologic processes at the cellular and molecular level, demonstrate the possible shift of medical imaging from a macroscopic and non-specific level to a microscopic and targeted scale. Cellular and molecular imaging now allows the investigation of specific pathways involved in inflammation (e.g., angiogenesis, cell proliferation, and recruitment, proteases generation, metabolism, gene expression). PET and SPECT imaging are the most commonly used "molecular" imaging modalities, but recent progress in MR, US, and optical imaging has been made. In the future, those techniques might enable a detection of inflammation at its very early stage, its quantification through the definition of biomarkers, and possibly demonstrate the response to therapy at molecular and cellular levels.

Thick corpus callosum: a clue to the diagnosis of fetal septopreoptic holoprosencephaly?

We describe fetal septopreoptic holoprosencephaly (HPE) associated with a thick corpus callosum (CC) diagnosed with MRI in a fetus at 31 weeks' gestation. Our report supports a recently published study connecting a thick fetal CC to other brain abnormalities. On diffusion tensor imaging (DTI), the body of the CC contained an abnormal longitudinal bundle, presumed to be a congenital heterotopic cingulum. Prenatal and postmortem brain MRI with DTI, CT, and pathological analyses are described and illustrated.

Cone-beam computed tomography arthrography: an innovative modality for the evaluation of wrist ligament and cartilage injuries.

PURPOSE: Cone-beam computed tomography (CBCT) has become an important modality in dento-facial imaging but remains poorly used in the exploration of the musculoskeletal system. The purpose of this study was to prospectively evaluate the performance and radiation exposure of CBCT arthrography in the evaluation of ligament and cartilage injuries in cadaveric wrists, with gross pathology findings as the standard of reference. MATERIALS AND METHODS: Conventional arthrography was performed under fluoroscopic guidance on 10 cadaveric wrists, followed by MDCT acquisition and CBCT acquisition. CBCT arthrography and MDCT arthrography images were independently analyzed by two musculoskeletal radiologists working independently and then in consensus. The following items were observed: scapholunate and lunotriquetral ligaments, triangular fibrocartilage complex (TFCC) (tear, integrity), and proximal carpal row cartilage (chondral tears). Wrists were dissected and served as the standard of reference for comparisons. Interobserver agreement, sensitivity, specificity, and accuracy were determined. Radiation dose (CTDI) of both modalities was recorded. RESULTS: CBCT arthrography provides equivalent results to MDCT arthrography in the evaluation of ligaments and cartilage with sensitivity and specificity between 82 and 100%, and interobserver agreement between 0.83 and 0.97. However, radiation dose was significantly lower (p < 0.05) for CBCT arthrography than for MDCT arthrography with a mean CTDI of 2.1 mGy (range 1.7-2.2) versus a mean of 15.1 mGy (range 14.7-16.1). CONCLUSION: CBCT arthrography appears to be an innovative alternative to MDCT arthrography of the wrist as it allows an accurate and low radiation dose evaluation of ligaments and cartilage.

Multimodal imaging approach to cerebral gas embolism lesions.

Cerebral gas embolism may be revealed by the sudden onset of unconsciousness sometimes after surgery or after diagnostic and therapeutic procedures. The clinical diagnosis may be difficult if the context is not relevant. Imaging can therefore play a crucial role in revealing the presence of intracranial gas bubbles on CT or MRI scans. This report is of a case of fatal cerebral gas embolism revealed by CT and MRI performed for deep and unexplained coma. Etiological diagnosis revealed the presence of a lung tumor invading the mediastinum, thus possibly allowing the migration of gas from the lung to the arterial cerebral circulation. A second MRI performed 8 days after the initial event with diffusion tensor imaging (DTI) and proton magnetic resonance spectroscopic imaging ((1)H-MRSI) allowed better comprehension of the pathophysiological mechanisms of cerebral injury secondary to gas embolism by showing two kinds of cerebral lesions: white-matter vasogenic edema and cytotoxic gray-matter edema.

Septic arthritis: monitoring with USPIO-enhanced macrophage MR imaging.

PURPOSE: To prospectively evaluate in vivo noninvasive monitoring of antibiotic therapy in experimental infectious arthritis by imaging macrophages by using magnetic resonance (MR) imaging enhanced with ultrasmall superparamagnetic iron oxide (USPIO) particles. MATERIALS AND METHODS: The institutional review committee on animal care approved the experimental protocol. Unilateral knee infection was induced by intra-articular injection of Staphylococcus aureus in 12 rabbits. Each rabbit underwent MR imaging before and after injection of USPIO particles, as well as before and after injection of gadoterate meglumine. All 12 of the animals were imaged during the acute phase of infection. Half were then sacrificed to obtain histopathologic samples, and the other half were imaged a second time after antibiotic treatment. MR imaging data were analyzed and compared with bacteriologic and histopathologic findings. RESULTS: In acute infections, intense synovitis with marked signal intensity increase of the synovium on gadoterate dimeglumine-enhanced fat-suppressed T1-weighted images was observed in all animals and was associated with areas of signal intensity loss within the infected synovium on USPIO-enhanced T2*-weighted gradient-echo images, reflecting an intense infiltration of USPIO-loaded macrophages. After antibiotic treatment and histologic evidence of healing infection, less synovial signal intensity loss was seen (P = .03). In contradistinction, the signal intensity increase on gadoterate dimeglumine-enhanced fat-suppressed T1-weighted images remained unchanged. CONCLUSION: In contrast to conventional MR imaging performed by using extracellular contrast agents, USPIO-enhanced macrophage MR imaging can demonstrate resolution of experimental bacterial joint infection.

Raine syndrome: expanding the radiological spectrum.

We describe ante- and postnatal imaging of a 1-year-old otherwise healthy girl with Raine syndrome. She presented with neonatal respiratory distress related to a pyriform aperture stenosis, which was diagnosed on CT. Signs of chondrodysplasia punctata, sagittal vertebral clefting and intervertebral disc and renal calcifications were also found on imaging. This new case confirms that Raine syndrome is not always lethal. The overlapping imaging signs with chondrodysplasia punctata and the disseminated calcifications give new insights into its pathophysiology.

Endoscopic Transorbital Approaches to Anterior and Middle Cranial Fossa: A Laboratory Investigation on Surgical Anatomy and Potential Routes.

Background Transorbital neuroendoscopic (TONES) approaches promise to open up new horizons for skull base surgery, offering alternative routes to reach the anterior and middle cranial fossa (ACF and MCF, respectively). Objective The aim of this anatomical study is to acquire new surgical anatomy knowledge and exploit it for the refinement of TONES approaches, as an alternative to open surgery, to reduce the distance to the target, and the risk of neurovascular lesions in pathological conditions extending beyond the orbital cavity. Materials and Methods Six head specimens (12 orbits) were studied/dissected. The orbit was approached and divided in a four clockwise quadrants manner to simulate three transconjunctival routes: the precaruncular (PC), preseptal (PS), and lateral retrocanthal (LRC), and one transpalpebral route-the superior eyelid crease (SLC). The boundaries and the most important anatomical landmarks were identified and are herein duly detailed with particular attention to the neurovascular structures encountered in each of those routes. Results The dissections showed that the PC approach facilitates the treatment of optic nerve and frontal sinus pathologies, whereas LRC appears safer to reach ACF and MCF allowing for a free multiplanar working channel (up to 180 degrees) to the floor, roof, and lateral-to-medial walls. Conclusion The plane of tendon lateral canthal's insertion and the sphenofrontal suture (SFS) were identified as the key anatomical landmarks for TONES approaches. Further studies are warranted to establish a practical clinical algorithm based on the anatomical four clockwise quadrants herein implemented/proposed, and the key surgical landmarks identified.

MRI of macrophages in infectious knee synovitis.

OBJECTIVE: The objective of our study was to prospectively evaluate macrophage imaging using ultrasmall superparamagnetic iron oxide (USPIO)-enhanced MRI to depict bacterial knee infection in an experimental rabbit model. SUBJECTS AND METHODS: Unilateral knee infection was induced by intraarticular injection of Staphylococcus aureus in eight rabbits. The contralateral knees were used as internal controls. After a mean interval of 3 days, two MRI sessions (3-T MRI) were performed before and 24 hours after IV administration of USPIO. The protocol included T1-weighted spin-echo, T2-weighted spin-echo, and T2*-weighted gradient-echo images. A gadolinium-enhanced T1-weighted sequence was also performed in the first session to optimize detection of synovial hyperplasia. MR data were analyzed qualitatively and quantitatively and compared with histopathologic findings (H and E stain and Perls Prussian blue stain). Signal-to-noise ratio changes after USPIO administration were compared using Wilcoxon's signed rank test. RESULTS: All inoculated knees presented infectious synovitis with intense infiltration of iron-loaded macrophages. In these infected knees, signal loss was determined visually and quantitatively on T1-weighted (p < 0.01), T2-weighted (p < 0.01), and T2*-weighted images (p < 0.01) 24 hours after USPIO administration, reflecting the presence of USPIO-loaded macrophages in the synovium. In contrast, no significant MR signal changes were observed in the control knees (p = 0.07-0.48), which presented a normal synovium without infiltration of iron-loaded macrophages. CONCLUSION: Macrophage imaging using USPIO-enhanced MRI can depict infectious knee synovitis.

Intercostal myositis ossificans misdiagnosed as osteosarcoma in a 10-year-old child.

Myositis ossificans (MO) is a rare benign cause of heterotopic bone formation within soft tissue. It most commonly affects adolescents and young adults, typically in the limbs and following trauma. Very few cases have been reported in children. We report here a case of nontraumatic MO occurring in a 10-year-old girl with an uncommon location in the 5th right intercostal space; it was initially misdiagnosed and treated as osteosarcoma. Imaging findings including plain radiographs, CT, MRI, bone scintigraphy and PET-CT are described. This case highlights the central role played by imaging in diagnosis, thus avoiding biopsy that can erroneously suggest osteosarcoma as the diagnosis, as occurred in this case.

EBV limbic encephalitis after allogenic hematopoietic stem cell transplantation.

The clinical and radiological presentations of Epstein-Barr virus (EBV) encephalitis are pleomorphic, but a common and characteristic finding is an increased T2-weighted signal in the bilateral thalami and basal ganglia. We report here a case of post-transplant acute limbic encephalitis (PALE) syndrome that was possibly related to EBV infection. Six weeks after hematopoietic stem-cell transplantation, the patient developed confusion and anterograde amnesia. Brain magnetic resonance imaging (MRI) was performed and revealed bi-hippocampal and amygdala signal abnormalities. The technetium-99m single-photon emission computed tomography ((99m)Tc SPECT) imaging confirmed bilateral limbic structural involvement. The clinical, biological and radiological presentations were consistent with a diagnosis of EBV-induced PALE syndrome. To our knowledge, this is the first described case of PALE syndrome possibly related to EBV infection.

Macrophage imaging by USPIO-enhanced MR for the differentiation of infectious osteomyelitis and aseptic vertebral inflammation.

The purpose of this study was to prospectively evaluate USPIO-enhanced MR imaging for the differentiation of vertebral infectious osteomyelitis and sterile inflammation. Vertebral osteomyelitis and sterile vertebral inflammation were induced in two groups of six rabbits each. MRI examinations were performed including unenhanced and gadolinium-enhanced fat-saturated SE T1w sequences. Once endplate enhancement was observed on the T1 gadolinium-enhanced MR sequence, a second MRI examination (SE T1w sequence) was performed 24 h after USPIO administration (45 micromol Fe/kg). MR imaging was correlated with histopathological findings (macrophage immunostaining and Perls Prussian blue staining). On gadolinium-enhanced T1 sequences, a significant SNR increase in vertebral endplates was present in both groups without significant difference between the two groups (P = 0.26). On USPIO-enhanced T1 sequences, a significant SNR increase was only observed in the infection group (P = 0.03) with a significant difference in SNR between the infection and the sterile-inflammation groups (P = 0.002). Infected areas presented replacement of bone marrow by an intense macrophage infiltration, some being iron-loaded. Sterile inflammation showed a replacement of bone marrow by inflammatory tissue with only rare macrophages without any Perls blue staining. USPIO-enhanced MR imaging can distinguish infectious osteomyelitis from sterile vertebral inflammation due to different macrophage distributions in the two lesions.

Macrophage activity in infected areas of an experimental vertebral osteomyelitis model: USPIO-enhanced MR imaging--feasibility study.

PURPOSE: To prospectively evaluate ultrasmall superparamagnetic iron oxide (USPIO) magnetic resonance (MR) imaging for the depiction of macrophages in infected areas of an experimental rabbit vertebral osteomyelitis model. MATERIALS AND METHODS: Lumbar vertebral osteomyelitis was induced in 10 rabbits with intradiscal injection of bacteria in a vertebral disk (test level) versus saline injection in another disk (control level). After a mean interval of 12 days, rabbits were imaged prior to and 24 hours after administration of USPIO. The MR imaging protocol included T1-weighted spin-echo, T2-weighted fast spin-echo, and T2*-weighted gradient-echo sequences. MR findings were compared with histologic findings (macrophage immunostaining and Perls Prussian blue staining). A Wilcoxon signed rank test was used to compare signal-to-noise ratio (SNR) results before and after USPIO administration. RESULTS: T1-weighted MR images of infected vertebral test levels obtained 24 hours after USPIO administration showed a significant increase in SNR (P = .005), whereas T2- and T2*-weighted images showed no significant changes in SNR (P = .14 and P = .87, respectively). Histologic examination results of infected areas demonstrated complete replacement of hematopoietic bone marrow by macrophage infiltration. Perls Prussian blue staining showed that some macrophages were iron loaded. T1- (P = .02), T2- (P = .04), and T2*-weighted (P = .04) images of control vertebrae showed a significant decrease in SNR. Histologic examination results confirmed the persistence of normal hematopoietic bone marrow without macrophage infiltration, which was reflected by more intensive Perls Prussian blue staining compared with that in infected areas. CONCLUSION: MR imaging can depict USPIO-loaded macrophage infiltration present in infected areas in an experimental rabbit model of vertebral osteomyelitis.

Multidetector CT arthrography of the wrist joint: how to do it.

With its exquisite spatial resolution, multidetector computed tomographic (CT) arthrography of the wrist is a valuable tool for the diagnosis and evaluation of a wide spectrum of articular disorders. Traumatic tears of the interosseous ligaments can be classified as complete or incomplete and as partial- or full-thickness tears at multidetector CT arthrography and can also be differentiated from asymptomatic degenerative lesions. In addition, tears of the triangular fibrocartilage complex can be differentiated according to their location. A tailored contrast material injection technique and multiplanar reformation are recommended for optimal assessment of these structures. Multidetector CT arthrography is also remarkably effective in demonstrating cartilage and bone abnormalities, many of which cannot be depicted with other imaging techniques. The chief limitation of multidetector CT arthrography lies in the evaluation of soft-tissue abnormalities, which may benefit from the addition of other imaging techniques such as ultrasonography or magnetic resonance imaging. A basic knowledge of the relevant anatomy, pathophysiologic features, and imaging technique is mandatory for obtaining high-yield diagnostic information concerning the wrist joint. (c) RSNA, 2008.

Wrist ligament tears: evaluation of MRI and combined MDCT and MR arthrography.

OBJECTIVE: The purpose of this study was to evaluate the performance of MRI and a combination of MDCT arthrography and MR arthrography in the diagnosis of tears and cartilage abnormalities of the wrist ligaments. SUBJECTS AND METHODS: The feasibility of combining MDCT arthrography and MR arthrography and performing them with an optimized contrast solution was evaluated in vitro and in vivo. Forty-five consecutively enrolled subjects with suspected wrist ligament tears underwent MRI and a combined MDCT and MR arthrographic procedure. Two observers reviewed the images for evidence of tears and cartilage abnormalities of the scapholunate and lunotriquetral ligaments and triangular fibrocartilaginous complex. Interobserver agreement was determined with kappa statistics, and the diagnostic accuracy of each technique was calculated. RESULTS: A 1:1 solution of 2.5 mmol/L tetraazacyclododecanetetraacetic acid (DOTA)-gadolinium and 300 mg I/mL iopamidol provided adequate contrast enhancement for both in vitro and in vivo MDCT arthrographic and MR arthrographic images. Interobserver agreement was substantial for MRI (kappa = 0.61) and MR arthrography (kappa = 0.71) and almost perfect for MDCT arthrography (kappa = 0.93). The sensitivity and specificity of MRI, MDCT arthrography, and MR arthrography for tears of the scapholunate ligament were 59% and 70%, 95% and 96%, and 68% and 87% for the first observer and 77% and 83%, 95% and 100%, and 77% and 87% for the second observer. For tears of the lunotriquetral ligament, these values were 30% and 94%, 100% and 94%, and 60% and 97% for the first observer and 50% and 97%, 90% and 100%, and 50% and 94% for the second observer. The three techniques appeared equivalent for complete tears of the scapholunate and lunotriquetral ligaments, but partial tears were significantly better visualized with MDCT arthrography. The sensitivity and specificity of MRI, MDCT arthrography, and MR arthrography for triangular fibrocartilaginous complex tears were 27% and 100%, 100% and 100%, and 82% and 100% for the first observer and 45% and 100%, 100% and 100%, and 82% and 100% for the second observer. For cartilage abnormalities, these values were 30% and 100%, 100% and 100%, and 30% and 100% for the first observer and 10% and 100%, 100% and 100%, and 40% and 100% for the second observer. CONCLUSION: MDCT arthrography appears more accurate than MRI and MR arthrography, particularly for discerning partial tears of the scapholunate and lunotriquetral ligaments that do not necessitate surgical therapy.

[Magnetic resonance imaging of the brain]. / Imagerie par résonance magnétique de l'encéphale.

MRI uses the magnetic properties of the hydrogen atoms present in the human body. It presents no risks as long as the contraindications (pacemaker, metal fragment in the eye, pregnancy less than 3 months) are complied with. MRI is the reference imaging method for exploration of the brain. The contrast of these images depends on the type of sequence used. More specific sequences (diffusio-weighted, gradient echo) and gadolinium injection can be added to the basic sequences (T1, T2, Flair).

Vascular Imaging Techniques of the Spinal Cord.

The various imaging techniques used to depict vascular lesions of the spinal cord are described in this article with particular emphasis on magnetic resonance imaging (MRI), vascular sequences, and advantages of high-field MRI. Technical vascular protocols are discussed in computed tomography, MRI, and conventional angiography. The diverse magnetic resonance angiography protocols are presented as well as their findings, specificities, and pitfalls. A review of the vascular anatomy and the most common pathologies analyzed by magnetic resonance angiography and conventional angiography is described.