Emergent neuroimaging of intracranial infection/inflammation

Infectious and inflammatory processes of the intracranial compartment often result in acute clinical presentations. The possible causes are legion. Clues to the diagnosis involve clinical presentation, laboratory analysis, and neuroimaging. This article reviews some of the salient factors in understanding intracranial infection/ inflammation, including pathophysiology and neuroimaging protocols/findings, and provides some examples and a few "pearls and pitfalls."     

Orbital and anterior visual pathway infection and inflammation

Introduction  Orbital and anterior visual pathway infection and inflammation represent approximately 10–15% of all orbital pathology. Both conditions can occur separately but occasionally they can be observed simultaneously. Methods  While the diagnosis of infection is usually straightforward, it is important to depict the lesions and to know the potential devastating complications. CT plays an important role in confirming the clinical suspicion of orbital infection. Results  The diagnosis and differential diagnosis of inflammation is more challenging. Differentiating inflammation from lymphoproliferative diseases and tumours can be difficult. Conclusion  MR imaging plays an important role but a dedicated orbital imaging protocol is mandatory.     

Head and neck infection and inflammation

This article discusses the imaging manifestations of infectious and inflammatory conditions of the head and neck. Special attention is paid to the sites, routes of spread, and complications of neck infections. Because the clinical signs and symptoms and the complications of these conditions are often determined by the precise anatomic site involved, anatomic considerations are stressed. Familiarity with the fascial layers, spaces of the neck, and the contents of each space is helpful for this discussion. The fascial layers of the neck are important barriers to infection, and once infection is established, the fascial layers play a part in directing its spread.     

Non-Contiguous Spinal Injury in Cervical Spinal Trauma: Evaluation with Cervical Spine MRI

Objective

We wished to evaluate the incidence of non-contiguous spinal injury in the cervicothoracic junction (CTJ) or the upper thoracic spines on cervical spinal MR images in the patients with cervical spinal injuries.

Materials and Methods

Seventy-five cervical spine MR imagings for acute cervical spinal injury were retrospectively reviewed (58 men and 17 women, mean age: 35.3, range: 18-81 years). They were divided into three groups based on the mechanism of injury; axial compression, hyperflexion or hyperextension injury, according to the findings on the MR and CT images. On cervical spine MR images, we evaluated the presence of non-contiguous spinal injury in the CTJ or upper thoracic spine with regard to the presence of marrow contusion or fracture, ligament injury, traumatic disc herniation and spinal cord injury.

Results

Twenty-one cases (28%) showed CTJ or upper thoracic spinal injuries (C7-T5) on cervical spinal MR images that were separated from the cervical spinal injuries. Seven of 21 cases revealed overt fractures in the CTJs or upper thoracic spines. Ligament injury in these regions was found in three cases. Traumatic disc herniation and spinal cord injury in these regions were shown in one and two cases, respectively. The incidence of the non-contiguous spinal injuries in CTJ or upper thoracic spines was higher in the axial compression injury group (35.3%) than in the hyperflexion injury group (26.9%) or the hyperextension (25%) injury group. However, there was no statistical significance (p > 0.05).

Conclusion

Cervical spinal MR revealed non-contiguous CTJ or upper thoracic spinal injuries in 28% of the patients with cervical spinal injury. The mechanism of cervical spinal injury did not significantly affect the incidence of the non-contiguous CTJ or upper thoracic spinal injury.     

MRI在脊柱结核诊断中的应用价值

目的 探讨MRI在脊柱结核诊断中的价值. 资料与方法 对34例临床疑脊柱结核者,术前行X线平片、MRI平扫及增强检查,并分别与手术病理结果 对比. 结果 34例中,最终诊断结核者33例,另1例为慢性化脓性炎. 33例结核X线平片诊断正确24例(72.7%),MRI均正确诊断(100%);1例慢性化脓性炎平片及MRI 均误诊为结核. 结论 MRI可清楚显示脊柱结核的骨髓水肿、椎体破坏、椎旁脓肿、间盘受累和椎管内改变,诊断准确率高,评价细致全面,并且能早期诊断.     

MR imaging of urgent inflammatory and infectious conditions affecting the soft tissues of the musculoskeletal system

Soft tissue infections and inflammatory conditions of the musculoskeletal system are a group of disorders commonly seen by emergency room physicians and radiologists. Many of these entities can either be limb- or life-threatening. Magnetic resonance imaging is currently the best imaging modality to evaluate these conditions. In this review, the characteristic imaging findings of cellulitis, abscess formation, necrotizing fasciitis, pyomyositis, diabetic ischemic infarction, acute and exertional compartment syndromes, and rhabdomyolysis will be emphasized as well as imaging factors that can help to differentiate these disorders.     

68Ga-枸橼酸PET/CT在炎症及感染疾病中的应用进展

炎症及感染的早期、准确诊断有利于及时有效地治疗。68Ga-枸橼酸是一种新型核医学正电子炎症示踪剂,能够与体内转铁蛋白结合,在病灶部位形成放射性浓集,且生产成本低、半衰期适中、辐射剂量低,在骨感染、腹腔感染、炎性肠病的诊断以及肺部病变良恶性的鉴别诊断中表现出良好的特性,尤其在骨感染早期的诊断及鉴别诊断中作用突出。就68Ga-枸橼酸PET/CT在炎症和感染显像方面的研究进展进行介绍。     

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 μmol 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.     

Spinal infection

Spinal infection is a significant cause of morbidity. Despite advances in antibiotic treatment regimens, the incidence is not decreasing due at least in part to an increase in 'at-risk' populations, namely the elderly and the immunocompromised. Prompt diagnosis is greatly facilitated by early and appropriate imaging techniques together with microbiological assessment following culture from blood, needle aspirate and biopsy material. This article gives an overview of imaging of spinal infection with an emphasis on MR imaging, which has greatly contributed to early diagnosis, thus allowing implementation of timely appropriate treatment. Received: 4 August 1998; Accepted: 10 September 1998     

脊椎骨嗜酸性肉芽肿的MRI诊断

目的分析脊椎骨嗜酸性肉芽肿的MRI表现,探讨MRI对该病的诊断价值。资料与方法回顾性分析10例经手术和病理证实的脊椎骨嗜酸性肉芽肿的MRI表现。结果10例脊椎骨嗜酸性肉芽肿主要表现为T1WI等或低信号,T2WI及STIR像为高或混杂信号;椎体呈楔形或扁平状,其中9例前后径增加,3例左右径增加;6例形成椎旁软组织肿块,其中5例表现为袖套状;邻近椎间盘形态正常或轻度膨隆;增强扫描,病变及周围软组织肿块呈明显不均匀强化。结论脊椎骨嗜酸性肉芽肿的MRI表现有一定特点,对于诊断和鉴别诊断具有重要价值。     

Tumoral calcinosis presenting as an extradural mass: MR findings and pathological correlation

Two cases of idiopathic tumoral calcinosis presenting as an extradural mass are reported. There are few reports in the literature of this pathological process presenting as extradural masses, so both cases represent very unusual locations for tumoral calcinosis. Magnetic resonance imaging features and pathological correlation of these two cases are presented. Tumoral calcinosis might be considered as a rare but possible cause of extradural mass.     

Scintigraphic detection of infection and inflammation: new developments with special emphasis on receptor interaction

Various conventional radiopharmaceuticals are currently available for scintigraphic imaging of infection and inflammation. Although a wide variety of infectious and inflammatory foci can be detected with these agents, several disadvantages limit their application. These limitations have stimulated the search for new radiopharmaceuticals. In the past decade a new class of radiopharmaceuticals has emerged: radiolabelled receptor-specific small proteins and peptides. These proteins and peptides are naturally occurring inflammatory mediators which specifically bind to receptors abundantly present in the area of inflammation. In addition, owing to their small size, they rapidly clear from all non-target tissues. This paper provides an overview of these newly developed agents, focussing on imaging characteristics and in vivo uptake mechanisms.     

Radiation-induced osteochondroma of the T4 vertebra causing spinal cord compression

A case of a radiation-induced osteochondroma arising from the vertebral body of T4 in an 18-year-old man is reported. The patient presented with a history of progressive left lower extremity weakness. At 7 years of age, he had undergone resection of a cerebellar medulloblastoma and received adjunctive craniospinal irradiation and systemic chemotherapy. Both CT and MR imaging revealed an extradural mass contiguous with the posteroinferior endplate of the T4 vertebral body. This case indicates that radiation-induced osteochondroma should be considered in the differential diagnosis of patients with symptoms of myelopathy or nerve root compression and a history of radiation therapy involving the spine in childhood.     

Amyloidosis of the spine in a patient on long-term hemodialysis

Summary A 54-year-old man with a history of renal failure treated with hemodialysis for over 10 years presented with clinical signs and symptoms and plain radiographic, computed tomographic and magnetic resonance imaging features of cervical vertebral osteomyelitis with spinal cord compression. Decompressive surgery revealed amyloid deposition. In the setting of chronic hemodialysis, differentation between amyloid deposition and osteomyelitis may not be possible on an imaging basis necessitating biopsy for diagnosis.     

脊柱孤立性浆细胞瘤的影像学表现

目的分析脊柱孤立性浆细胞瘤的X线、CT和MRI表现,提高对浆细胞瘤的认识和诊断水平。资料与方法回顾性分析16例经临床病理证实的脊柱孤立性浆细胞瘤,总结分析其影像学表现。结果 16例脊柱孤立性浆细胞瘤患者年龄36～69岁(平均54岁),男女比例3∶1,1例发生在颈椎,10例发生在胸椎,5例发生在腰椎,病程从半个月到3年不等,病椎附近疼痛是共同的首发症状。X线和CT表现为脊椎单发溶骨性破坏,椎体膨胀性改变,边界清晰,无骨膜反应,可残存较厚的骨嵴。MRI表现为T1低等信号,T2高信号,增强扫描均匀强化,MRI可以更加清晰地显示软组织肿块,局限性终板骨折,椎管受累及脊髓受压。结论 X线平片表现为单发病变,膨胀性溶骨性破坏,无骨膜反应,X线检查可以作为孤立性浆细胞瘤的初筛。CT和MRI可以明确脊柱孤立性浆细胞瘤的病变范围和形态特征,为该病的诊断、鉴别提供更多的信息,溶骨性病变、软组织肿块、椎弓根、椎间盘及相邻椎体受累是病变的主要表现。     

MR imaging of spinal infection: atypical features, interpretative pitfalls and potential mimickers

The wide variability of MR features in spinal infection reflects rare distribution of discovertebral involvement, unexpected soft-tissue and bone abnormalities, unusual complications or uncommon pathogens. In addition, several degenerative and inflammatory entities can clinically and radiologically resemble spinal infection. In this pictorial review, we illustrate the various atypical features that may be found in MR imaging of spinal infection, with emphasis on interpretative pitfalls and common mimickers.