Atypical, unusual, and misleading imaging presentations of spondylolysis.

Although lumbar spondylolysis is a widely known and easily recognizable condition in its typical presentation, there are some less well-known forms that may occasionally be challenging and/or demand special attention on imaging. Examples include: acute and/or incomplete lesions; unilateral defects; lesions at unusual levels (cervical, upper lumbar, and multi-level spondylolyses); iatrogenic lesions; non-isthmic spondylolysis; and spondylolysis related to underlying diseases. In addition to their atypical, uncommon or confusing imaging presentations, these forms of spondylolysis are far rarer than the classic type and have been described, to a great extent, in the surgical literature, thus reducing the awareness of radiologists about them and raising the potential for misdiagnosis and inadequate treatment. In this review the authors address these special manifestations of spondylolysis, stressing the more important features to be considered in the differential diagnosis and the impact of a precise diagnosis of spondylolysis on the patient's care.

MRI of subchondral fractures: a review.

Several authors have recently emphasized the role of magnetic resonance imaging (MRI) in the diagnosis of subchondral fractures. There is increasing interest about this type of fractures, mostly because they have been implicated in the genesis of some well-known destructive articular conditions whose cause was previously undetermined, such as distal clavicular osteolysis, rapidly progressive osteoarthritis of the hip, spontaneous osteonecrosis of the knee and adult-type Freiberg's infraction. Subchondral fractures may ultimately lead to bone collapse, secondary osteonecrosis and severe articular damage, and there may be rapid progression of joint destruction over a period of weeks to months. It has been suggested that timely diagnosis might potentially improve the outcome and avoid the onset of destructive joint disease, making MRI even more important in this setting. The fracture line usually appears as a band of low signal intensity in the subchondral bone plate, adjacent to the articular surface, most often surrounded by bone marrow edema. In this article the authors review the most relevant imaging features of subchondral fractures in several joints, stressing the importance of early recognition for a better outcome.

Imaging diagnosis of early rheumatoid arthritis.

Early diagnosis of rheumatoid arthritis is essential for its proper management. Currently, the initial phase of rheumatoid arthritis is known to provide a window of therapeutic opportunity. Although the diagnosis is primarily clinical, the development and improvement of laboratory and imaging methods have contributed to earlier diagnosis and determination of procedures in early rheumatoid arthritis. In this article, the authors review the role of the major imaging methods used for assessing early rheumatoid arthritis, especially conventional radiography, ultrasonography, and magnetic resonance imaging.

Diagnóstico por imagem da artrite reumatoide inicial / Imaging diagnosis of early rheumatoid arthritis

O diagnóstico precoce da artrite reumatoide é essencial para o manejo adequado da condição. Atualmente, considera-se que a fase inicial da doença constitui uma janela de oportunidade terapêutica para a artrite reumatoide. Embora o diagnóstico seja primordialmente clínico, o desenvolvimento e o aprimoramento de métodos laboratoriais e de imagem têm contribuído para o diagnóstico mais precoce e a determinação da conduta na artrite reumatoide inicial. Neste artigo os autores revisam o papel dos principais métodos de imagem utilizados para a avaliação da artrite reumatoide inicial, notadamente a radiologia convencional, a ultrassonografia e a ressonância magnética.

Early diagnosis of rheumatoid arthritis is essential for its proper management. Currently, the initial phase of rheumatoid arthritis is known to provide a window of therapeutic opportunity. Although the diagnosis is primarily clinical, the development and improvement of laboratory and imaging methods have contributed to earlier diagnosis and determination of procedures in early rheumatoid arthritis. In this article, the authors review the role of the major imaging methods used for assessing early rheumatoid arthritis, especially conventional radiography, ultrasonography, and magnetic resonance imaging.

Unilateral dysgenesis of the internal carotid artery: spectrum of imaging findings.

OBJECTIVE: Dysgenesis of the internal carotid artery (ICA) is a broad term comprising hypoplasia, aplasia and agenesis of the vessel. It is a rare anomaly, often clinically silent, that can be confidently diagnosed by means of noninvasive imaging methods. METHODS: After a review of teaching files, 7 patients with unilateral carotid dysgenesis were found, 2 with agenesis of the ICA, 3 with carotid aplasia, and 2 with hypoplasia of the vessel. Computed tomography (CT) and magnetic resonance angiography (MRA) of the brain were performed in all patients, with a complete magnetic resonance of the brain in 3 of them, a CT angiography of the brain in one, and MRA of the cervical arteries in 3. RESULTS: The fetal pattern of arterial circulation was found in 3 patients with agenesis/aplasia of the ICA and the adult pattern was found in 2 patients, being the brain circulation of normal pattern in the patients with hypoplasia of the ICA. Two patients presented signs of reduced flow to the brain hemisphere ipsilateral to the carotid dysgenesis; one of them with an old homolateral brain infarction. CONCLUSION: Far from being just an anatomic curiosity, the dysgenesis of the ICA may have serious consequences if not recognized prior to endarterectomies, carotid ligation or transsphenoidal surgery. As much as one-third of these patients will have intracranial aneurysms as well. The imaging methods, instead being mutually exclusive, are complementary in the evaluation of carotid dysgenesis.

Chronic eosinophilic pneumonia secondary to long-term use of nitrofurantoin: high-resolution computed tomography findings.

The authors report the case of a female patient who developed chronic eosinophilic pneumonia secondary to long-term use of nitrofurantoin for prophylaxis of recurrent urinary tract infections due to urethral stenosis. On high-resolution computed tomography scans, the pulmonary reaction to nitrofurantoin most commonly manifests as an interstitial-alveolar pattern in both lung bases. However, in this case, the alterations were most pronounced in the periphery of the upper lobes. In itself, this tomographic profile is strongly indicative of chronic eosinophilic pneumonia. The patient had previously been submitted to an open lung biopsy. The diagnosis of chronic eosinophilic pneumonia was confirmed through a review of the biopsy.

Pneumonia eosinofílica crônica secundária ao uso prolongado de nitrofurantoína: achados da tomografia computadorizada de alta resolução do tórax / Chronic eosinophilic pneumonia secondary to long-term use of nitrofurantoin: high-resolution computed tomography findings

Os autores relatam o caso de uma paciente com estenose de uretra que desenvolveu pneumonia eosinofílica crônica secundária ao uso prolongado de nitrofurantoína como profilaxia para infecção urinária de repetição. A paciente havia sido submetida a uma biópsia pulmonar a céu aberto. É dada ênfase aos achados da tomografia computadorizada de alta resolução do tórax, já que, embora as alterações pulmonares associadas à toxicidade da nitrofurantoína geralmente sejam basais e bilaterais, no caso aqui descrito, as lesões de natureza interstício-alveolares situaram-se nas regiões subpleurais dos lobos superiores. Esses achados, por si só, são muito sugestivos de pneumonia eosinofílica crônica. O diagnóstico foi confirmado por meio da revisão da biópsia.

The authors report the case of a female patient who developed chronic eosinophilic pneumonia secondary to long-term use of nitrofurantoin for prophylaxis of recurrent urinary tract infections due to urethral stenosis. On high-resolution computed tomography scans, the pulmonary reaction to nitrofurantoin most commonly manifests as an interstitial-alveolar pattern in both lung bases. However, in this case, the alterations were most pronounced in the periphery of the upper lobes. In itself, this tomographic profile is strongly indicative of chronic eosinophilic pneumonia. The patient had previously been submitted to an open lung biopsy. The diagnosis of chronic eosinophilic pneumonia was confirmed through a review of the biopsy.

Lead arthropathy: radiographic, CT and MRI findings.

OBJECTIVE: Lead arthropathy is a well-known complication of gunshot injuries with retained intra-articular bullets. Although several previous reports have discussed the radiological findings of this entity, computed tomography (CT) and magnetic resonance imaging (MRI) findings have never been described before in this setting. MATERIALS AND METHODS: In this paper the authors review the imaging findings of 11 patients with lead arthropathy (1 of whom had clinical signs of lead poisoning as well), all of them studied by means of radiographs. In addition, non-enhanced CT scans were obtained in 3 patients and gadolinium-enhanced MRI in 1. RESULTS: Classic findings of intra-articular speckled lead deposits (occasionally with a "lead arthrogram" appearance), joint space narrowing and preserved bone density were found at radiographs in the great majority of cases. Furthermore, extension of intra-articular lead to adjacent tendon sheaths was observed in almost half of the patients, an observation rarely reported in the literature. CT scans and MRI, in their turn, were superior with regard to soft tissue abnormalities, accurately depicting joint effusion and the thickened synovium with lead particles embedded in it. CONCLUSION: Post-gadolinium MRI had the advantage of showing the enhancement pattern of the inflamed synovium and associated bone marrow edema pattern. Although it is not possible to establish the role of axial imaging in lead arthropathy from the small number of cases studied, this initial experience shows that both methods hold promise in this setting and may be useful, at least in selected cases.

Anomalias congênitas da veia cava inferior: valor dos métodos multiplanares em seu diagnóstico: ensaio iconográfico / Congenital anomalies of the inferior vena cava: importance of multiplanar imaging methods: an iconographic essay

A formação da veia cava inferior é o resultado de um complexo processo embriológico que se dá entre seis e oito semanas de vida intra-uterina. Numerosas variações no desenvolvimento deste vaso podem ocorrer, decorrentes de embriogênese aberrante, resultando no surgimento de variantes anatômicas. Embora boa parte delas seja assintomática, é imperativo que o radiologista esteja familiarizado a elas, já que o seu não-reconhecimento tem implicações médico-legais sérias, como em pacientes candidatos a manuseio cirúrgico abdominal ou procedimentos hemodinâmicos, porexemplo. Neste trabalho, o diagnóstico por imagem das principais anomalias congênitas da veia cava inferior é abordado sob a forma de um ensaio iconográfico, ressaltando-se a importância dos métodos multiplanares (tomografia computadorizada com aquisições volumétricas e ressonânciamagnética) neste contexto.

The inferior vena cava is the result of a complex embryologic process which takes place between 6 and 8 weeks of intra-uterine life. Several variations can occur during this process, and a defective embryogenesis of this vessel may lead to the development ofanatomic variants. Although many of these variants are asymptomatic,the radiologist should be aware of them and of the potential medico-legal issues involved, especially in cases in which abdominal surgery or hemodynamic procedures are contemplated. In thispaper, the major congenital anomalies involving the inferior vena cava are reviewed under the form of a pictorial essay, highlighting the role of the multiplanar imaging methods (volumetric computed tomography and magnetic resonance imaging) in their diagnosis.

Hipoplasia da veia cava inferior: relato de caso e revisão da literatura / Hypoplasia of the inferior vena cava: a case repost and review of the literature

Erros na embriogênese da veia cava inferior podem levar a vários tipos bem conhecidos de anomalias de desenvolvimento deste vaso. Entretanto, hipoplasia de toda a sua extensão abdominal é bastante rara, e a maioria dos casos previamente descritos como hipoplasia da veia cava inferior refere-se, na verdade, a hipoplasia ou atresia segmentares. Os autores descrevem os achados à tomografia computadorizada e à angio-ressonância magnética de um homem de 49 anos com antecedentes remotos de trombose bilateral das veias femorais comuns e hipoplasia de toda a veia cava inferior abdominal, apresentando-se com extensa rede colateral em abdome e pelve (inclusive com evidências de derivação sistêmico-portal), dilatação compensatória do sistema ázigos/hemi-ázigos e doença varicosa grave de membros inferiores. A ocorrência de trombose venosa profunda em pacientes jovens, especialmente quando proximal, bilateral ou recorrente, deve levantar a possibilidade de anomalias da veia cava inferior, sendo a angio-ressonância e a tomografia computadorizada contrastada especialmente úteis neste contexto.

Defective embryogenesis of the inferior vena cava may lead to several well-known types of developmental anomalies of this vessel. However, hypoplasia of the whole abdominal portion seems to be very rare, and most cases previously described as hypoplasia of inferior vena cava are related to segmental hypoplasia or atresia. The authors describe the computed tomography and magnetic resonance angiography findings of a 49-yearold man with remote antecedents of bilateral thrombosis of the common femoral veins and unsuspected hypoplasia of the entire abdominal inferior vena cava incidentally discovered, presenting with extensive collaterals in the abdomen and pelvis (including evidences of systemic-to-portal shunting), compensatory dilatationof the azygous/hemiazygous system and severe varicose disease in his lower limbs. Deep venous thrombosis in youngpatients, especially when proximal, bilateral or recurrent should raise the possibility of anomalies of the inferior vena cava, and magnetic resonance angiography and contrast-enhanced computed tomography are particularly useful in this setting.

Avulsão da espinha ilíaca ântero-inferior: aspectos dos achados de imagem / Avulsion fractures of the interior iliac spine: spectrum of imaging findings

Lesões avulsivas das apófises pélvicas são relativamente comuns em atletas entre 13 e 18 anos, principalmente, no Brasil, entre jogadores de futebol. O diagnóstico é estabelecido clinicamente e através dos exames de imagem. Fases aguda, reparativa e consolidada são encontradas nessas lesões, todas com características de imagem distintas. Enquanto as fases aguda e consolidada habitualmente não apresentam maiores dificuldades diagnósticas, a fase reparativa freqüentemente exibe aspecto agressivo aos exames de imagem, simulando lesão neoplásica. Neste artigo, os autores apresentam os achados de avulsões da espinha ilíaca ântero-inferior às radiografias convencionais, à tomografia computadorizada e à ressonância magnética, enfatizando as características típicas dos três estágios evolutivos destas lesões.

Osteoartropatia neurotrófica: ensaio iconográfico / Neuropathic osteoarthropathy: iconographic essay

A osteoartropatia neurotrófica caracteriza-se por uma artropatia crônica destrutiva, não-infecciosa, que se desenvolve em pacientes com alguma forma de perda da propriocepção ou da sensibilidade à dor, sendo o diabetes mellitus a causa mais freqüente no mundo contemporâneo. O quadro radiográfico clássico é o de fragmentação óssea, osteofitose, derrame e instabilidade articular, com densidade óssea preservada. Embora a radiologia convencional seja o método de imagem mais utilizado na avaliação da osteoartropatia neurotrófica, a tomografia computadorizada, a ressonância magnética e a medicina nuclear são importantes no estudo de casos complexos, especialmente quando a possibilidade de infecção for considerada. Neste artigo, as principais etio-logias da osteoartropatia neurotrófica e o papel dos métodos de imagem são abordados sob a forma de um ensaio iconográfico.

Tumores ósseos primários da coluna vertebral: ensaio iconográfico / Primary bone tumors of the spine: iconographic essay

Bem mais raros que as condições neoplásicas metastáticas ou linfoproliferativas da coluna, os tumores vertebrais primários devem ser sempre suspeitados quando uma lesão vertebral solitária for identificada. 0 diagnóstico diferencial, no entanto, depende do conhecimento do modo de apre-sentação de cada tumor nas diversas modalidades de exames de imagem. Os principais achados radiológicos deste grupo de enfermidades são descritos sob a forma de um ensaio iconográfico baseado em casos clínico-radiológicos.

Cavernous angioma of the cavernous sinus: imaging findings.

Cavernous angiomas (cavernomas) of the cavernous sinus are uncommon, with only scattered reports in literature. Unlike their parenchymatous counterparts, they are intensely enhancing para-sellar masses, iso/hypointense in T1- and hyperintense in T2-weighted images. Differential diagnosis with para-sellar meningiomas and schwannomas can be difficult. We report three cases of this condition, describing findings of diffusion-weighted imaging in this kind of lesion for the first time in literature.

Cavernous angioma of the cavernous sinus: imaging findings

Angiomas cavernosos (cavernomas) do seio cavernoso são lesões incomuns, com poucos relatos na literatura especializada. Ao contrário dos cavernomas parenquimatosos, são massas para-selares intensamente captantes, isointensas a hipointensas em T1 e hiperintensas em T2 nas imagens de ressonância magnética. O diagnóstico diferencial com meningiomas e schwannomas para-selares pode ser difícil. Relatamos os achados de imagem de três casos desta entidade, descrevendo os achados da ressonância magnética ponderada em difusão neste tipo de lesão pela primeira vez na literatura.