The value of computed tomography in osseous hydatid disease (Echinococcosis)

The authors report three cases of osseous hydatid disease (echinococcosis) in which examination by computed tomography (CT) was found to be helpful in establishing the diagnosis. Recognition of this rare bone infection in orthodox radiographs is notoriously difficult, but is aided by knowledge of the patient having lived in an area in which the disease is endemic. In two instances, one involving the shoulder and the other the thoracic spine, radiological abnormalities had been attributed at first to tuberculosis. In the third case, in which a destructive lesion in the sacrum had been interpreted correctly, CT studies provided confirmation of a recurrence.CT has proved to be an effective and sensitive method of demonstrating these destructive lesions in bone, of determining their spread, and of establishing the presence of other hydatid cysts in adjacent soft tissues. This technique has been found to be of value in preoperative planning of the surgical approach to hydatid lesions of the skeleton.     

Local complications of hydatid disease involving thoracic cavity: imaging findings

Hydatid disease, a worldwide zoonosis, is caused by the larval stage of the Echinococcus tapeworm. Although it can involve almost every organ of the body, lung involvement follows in frequency the hepatic infestation in adults and is the predominating site in children. Radiologically, hydatidosis usually demonstrates typical findings, but many patients are at risk of developing various complications of hydatid disease with atypical imaging findings and these are rarely described in the literature. In this pictorial review, the imaging features of local complications of hydatid disease involving the thorax including intrapulmonary or pleural rupture, infection of the ruptured cysts, reactions of the adjacent tissues, thoracic wall invasion and iatrogenic involvement of pleura are described. Additionally, imaging characteristics of transdiaphragmatic thoracic involvement of hepatic hydatid disease are presented. To prevent the development of subsequent catastrophic results, all radiologists need to be aware of the atypical imaging appearances of complications of pulmonary hydatid disease.     

Correlation between computed tomographic and magnetic resonance imaging findings of parenchymal lung diseases

Computed tomography (CT) is considered to be the gold standard method for the assessment of morphological changes in the pulmonary parenchyma. Although its spatial resolution is lower than that of CT, MRI offers the advantage of characterizing different aspects of tissue based on the degree of contrast on T1-weighted image (WI) and T2-WI. In this article, we describe and correlate the MRI and CT features of several common patterns of parenchymal lung disease (air trapping, atelectasis, bronchiectasis, cavitation, consolidation, emphysema, ground-glass opacities, halo sign, interlobular septal thickening, masses, mycetoma, nodules, progressive massive fibrosis, reverse halo sign and tree-in-bud pattern). MRI may be an alternative modality for the collection of morphological and functional information useful for the management of parenchymal lung disease, which would help reduce the number of chest CT scans and radiation exposure required in patients with a variety of conditions.     

Clear cell chondrosarcoma: radiographic, computed tomographic, and magnetic resonance findings in 34 patients with pathologic correlation

Objective To describe the radiographic features of clear cell chondrosarcoma (CCCS), including the computed tomographic (CT) and magnetic resonance (MR) findings, and to correlate them with the histopathologic findings.Design and patients A retrospective review was carried out of 72 patients with histopathologically confirmed CCCS. Imaging studies were available for 34 patients: conventional radiographs (n=28), CT scans (n=14), and MR images (n=15). Radiographic studies were reviewed by three radiologists who rendered a consensus opinion; the studies were correlated with the histopathologic findings.Results Of the 34 patients with imaging studies, 30 were male and 4 were female (mean age 38.6 years; range 11–74 years). Twenty-two lesions were in long bones (15, proximal femur; 1, distal femur; 1, proximal tibia; 5, proximal humerus) and 11 were in flat bones (5, vertebra; 4, rib; 1, scapula; 1, innominate). One lesion occurred in the tarsal navicular bone. Typically, long bone lesions were located in the epimetaphysis (19/22) and were lucent with a well-defined sclerotic margin and no cortical destruction or periosteal new bone formation. More than one-third of the long bone lesions contained matrix mineralization with a characteristic chondroid appearance. Pathologic fractures were present in six long bone lesions (4, humerus; 2, femur). Lesions in the proximal humerus were more likely to have indistinct margins (4/5) and extend into the diaphysis. Flat bone lesions were typically lytic and expansile and occasionally demonstrated areas of cortical disruption. Typically, matrix mineralization, when present, was amorphous. MR imaging, when available, was superior to conventional radiographs for demonstrating the intramedullary extent of a lesion as well as soft tissue extension. CT images better delineated the presence of cortical destruction and the character of matrix mineralization patterns. CCCS lesions were typically low signal intensity on T1-weighted images and moderately or significantly bright on T2-weighted images. Areas of lesion heterogeneity on T1- and T2-weighted images and on post-gadolinium T1-weighted images corresponded pathologically to areas of mineralization, intralesional hemorrhage, and cystic changes. Adjacent bone marrow edema was typically absent (12/15) or only minimally observed in a few cases (3/15). No cases examined with MR imaging demonstrated periosteal new bone formation.Conclusions CCCS typically presents radiographically as a geographic lytic lesion located in the epimetaphyseal region of long bones. Most commonly lesions are found in the proximal femur, followed by the proximal humerus. Lesions within the proximal humerus may exhibit more aggressive features. Lesions in the axial skeleton are typically expansile and destructive, often with soft tissue extension and lack of mineralization. MR imaging may show the presence or absence of bone marrow edema.     

Benign bone tumors

A solid knowledge of underlying histopathology of benign bone tumors aids in differential diagnoses of these tumors. Important factors in diagnosis of a bone tumor include patient age and gender; the bone involved; the location of the tumor along, within, or on the bone; lesion margin; matrix proliferation; and periosteal reaction. This article provides a review of the origin of the tumor matrix and its influence on the imaging properties of these tumors.     

Albendazole treatment of cerebral hydatid disease: evaluation of results with CT and MRI

We report a case of cerebral hydatid disease demonstrated by CT and MRI, treated with albendazole. Follow-up showed complete dissapearance of the cysts with residual focal calcification on CT and presumed gliosis on MRI. Received: 25 April 1997 Accepted: 25 May 1997     

Pelvic hydatid disease: CT and MRI findings causing sciatica.

Pelvic masses, especially hydatid disease, rarely present with sciatica (1, 2). We present the computed tomography (CT) and the magnetic resonance imaging (MRI) findings of a 49-year-old female patient with presacral hydatid disease, who was evaluated for her sciatica. We also want to emphasize the importance of assessing the pelvis of patients with symptoms and clinical findings that are inconsistent and that cannot be satisfactorily explained by the spinal imaging findings.     

骨原发性恶性纤维组织细胞瘤影像诊断

目的探讨骨原发性恶性纤维组织细胞瘤(BMFH)影像表现及诊断要点。方法回顾性分析6例经病理确诊为BMFH的X线、CT及MRI表现。结果4例侵犯单骨,2例侵犯多骨。溶骨型4例,混合型2例。股骨下端3例,肱骨上端1例,楔骨1例,横突1例,共侵犯12个骨骼。6例均有骨及骨皮质明显破坏,以溶骨性破坏为主,2例病灶周围有轻度骨硬化。全部病例均有软组织肿块,巨大肿块2例,局限性肿块4例,1例肿块内可见散在小钙化影。全部病例未见骨膜反应,3例合并病理性骨折。结论原发性BMFH好发于长骨干骺端或骨端,多见于股骨下端及胫骨上端。虫蚀状或大片状溶骨性骨质破坏,巨大软组织肿块,无骨膜反应,是其影像学特点,诊断需密切结合临床和病理。     

CT and MRI in hydatid disease of cervical vertebrae

Summary Hydatid disease (HD) of the cervical spine is rare. A case investigated by computed tomography (CT) and magnetic resonance imaging (MRI) is presented. While CT shows the bone lesion better, MRI is superior in demonstrating compression of neural structures. The complementary use of CT and MRI in such cases is suggested.     

The performance of MRI in detecting subarticular bone erosion of sacroiliac joint in patients with spondyloarthropathy: A comparison with X-ray and CT

Objective

To assess the sensitivity and specificity of detecting subarticular bone erosion of sacroiliac (SI) joint in patients with spondyloarthritis (SpA) using MRI three-dimensional water selective balanced steady-state free precession sequence (3D-WS-bSSFP) and T1-weighted (T1W) sequence.

Materials and methods

Radiography, CT and MRI of SI joint from 43 SpA patients were retrospectively analyzed. MRI examination sequences include T1W, short tau inversion recovery (STIR) and 3D-WS-bSSFP. Two radiologists, blinded to clinical data, independently determined bone erosion at bilateral sacral and iliac sides of the SI joint on radiography, CT, T1W and 3D-WS-bSSFP respectively. X² test was used to compare the sensitivity of detecting bone erosion among different diagnostic methods.

Results

Of the 86 sacral and 86 iliac articular surfaces from the 43 cases, radiography, CT, MRI T1W and 3D-WS-bSSFP showed the presence of bone erosion in 40, 74, 50 and 71 articular surfaces respectively. CT and MRI 3D-WS-bSSFP demonstrated similar sensitivity (x² = 0.11, P = 0.74), and both were superior to radiography (x² = 15.17, P < 0.01 and x² = 12.78, P < 0.01, respectively) and T1W (x² = 7.26, P < 0.01 and x² = 5.62, P < 0.05). Using CT diagnosis as the gold standard, the sensitivity and specificity of detecting bone erosion for MRI 3D-WS-bSSFP and T1W sequences were 91.8%, 96.9%, and 60.8%, 94.9% respectively.

Conclusion

MRI 3D-WS-bSSFP sequence is associated with short scanning time, zero ionizing radiation, high sensitivity and specificity of displaying the subarticular bone erosion of SI joints in patients with SpA. Therefore, it can be considered an alternative to CT.     

Acute small bowel ischemia: spectrum of computed tomographic findings

Acute small bowel ischemia is an important clinical entity with significant morbidity and mortality. Since the clinical presentation is often nonspecific, abdominal computed tomography (CT) is frequently obtained for the evaluation of patients with equivocal or unsuspected intestinal ischemia. In this article, the direct and ancillary CT findings of acute small bowel ischemia are reviewed. Although the individual CT manifestations are rarely specific, awareness of the spectrum of CT findings of small intestinal ischemia can help to suggest the diagnosis and direct appropriate management.     

Patterns of skull base fracture: a three-dimensional computed tomographic study

Three-dimensional (3D) computed tomographic (CT) reconstructions were studied retrospectively in 14 patients with skull base fractures. Our aim was to assess the clarity of visualisation and pattern of these fractures. The reformations were obtained from 3 mm thick two-dimensional (2D) CT images. The 2D data stored on optical discs were retrieved and reformatted using the scanner's software. The 3D technique could demonstrate the presence of fractures as well as 2D images. It was of special value in defining the depth and extent of fractures in the floor of the cranial fossae. Undisplaced and displaced fractures could both be demonstrated. Fractures in the anterior fossa run diagonally towards the midline and then cross the cribriform plate of the ethmoid bone. Fractures of the middle fossa run obliquely anteroposterior. Fractures in the lamina papyracea and cribriform plate were difficult to reconstruct due to the the thinness of these bones and threshold definitions. The volume of the 3D block determines the angles suitable for viewing the fractures. In spite of present technical difficulties, the 3D images are of greater anatomical and diagnostic value, particularly in anterior fossa fractures. There is no additional radiation risk to the patient, since reconstructions are made from routine 2D images.     

Radiographic,CT and MRI spectrum of hydatid disease of the chest: a pictorial essay

Thirty patients with thoracic hydatidosis (Echinococcus granulosus) were studied. The hydatid cysts were located in the lung parenchyma (70%), mediastinum (6.7%), inside the heart (10%), the pleurae (10%) and the chest wall (3.3%). complications of thoracic hydatid cysts, such as rupture, infection, pleural involvement, spread and calcifications are presented. Computed tomography (CT) without and/or with contrast enhancement was performed in all patients (30). Findings from conventional chest radiographs were compared with CT and confirmed by pathology (30). In 10 cases (33.3%), magnetic resonance imaging was also performed. The diagnostic spectrum of hydatid cysts, including variations and developmental stages, is presented in this pictorial essay.     

Calf hematoma — computed tomographic and magnetic resonance findings

Four patients with hematomas of the calf are presented. The diagnosis was made by computed tomography (CT) in three cases and CT/magnetic resonance imaging (MRI) in one case. In all cases, CT or MRI clarified a confusing clinical picture. CT and MRI can help differentiate the types of calf mass (i.e., hematoma, tumor, Baker cyst, thrombophlebitis) and assist proper clinical management in a rapid, noninvasive fashion.     

Imaging of periosteal reactions associated with focal lesions of bone

Periosteal reaction (PR) is the response of cortical bone to an underlying insult. It is manifest in a limited number of histological and radiological patterns. Although not specific for a particular diagnosis, the appearance of PR aids the radiological characterization of bone lesions. Once ossified, PR is demonstrated well on plain radiography but can also be visualized on ultrasound, CT, MRI and bone scintigraphy, particularly in the early stage. This article provides a pictorial review of the patterns of PR with particular reference to bone tumours.     

Dumbbell-shaped thoracic hibernoma: computed tomography and magnetic resonance imaging findings

Hibernoma is an uncommon, benign soft tissue tumor that arises in brown adipose tissue. The computed tomography (CT) and magnetic resonance imaging (MRI) findings of hibernomas are similar to those of well-differentiated liposarcoma or angiolipoma. We report the unique appearance of a rare thoracic wall hibernoma, which appeared as a dumbbell-shaped lipomatous tumor across an intercostal region. A dynamic contrast-enhanced study on MRI revealed early enhancement, which corresponded to the branching low-signal intensity on T2-weighted images of the mass.     

Tuberculosis of the parotid gland: computed tomographic findings

Background: Tuberculosis (TB) of the parotid gland is rare, even in endemic regions. Approximately 100 cases have been reported in the English literature. The computed tomographic (CT) features, however, have seldom been studied.

Purpose: To determine the diagnostic CT features of tuberculosis of the parotid gland.

Material and Methods: CT studies of four histologically proven cases of tuberculosis of the parotid gland were retrospectively reviewed.

Results: A total of 15 enlarged lymph nodes were found in the superficial lobes of the parotid glands. The nodes were arranged linearly within the gland. Enhancement patterns included homogeneous enhancement (9/15, 60%), homogeneous enhancement with eccentric microcysts (3/15, 20%), and thick-walled rim enhancement with central lucency (3/15, 20%). Thickened adjacent fascial plane and platysma were seen in two patients. Ipsilateral cervical lymphadenopathy was seen in all patients.

Conclusion: In patients presenting with unilateral parotid nodules, TB should be considered when linearly arranged enhancing nodules are demonstrated in the superficial lobes of the glands on CT scan.     

Magnetic resonance imaging of bone and soft tissue tumors: Early experience in 31 patients compared with computed tomography

In 31 patients with 21 soft tissue and 10 bone tumors, magnetic resonance imaging (MRI) and computed tomography (CT) were equally effective in delineating the margins of most soft tissue tumors, and the margins of bone tumors from fat and adjacent normal bone. However, MRI was superior to CT in delineating bone tumors from adjacent muscle, and in showing the relationships to bone of the deep margins of some soft tissue tumors. This was true because the quality of CT images around thick cortical bone often was severely degraded by streak artifact, which does not occur in MRI.Excellent anatomic detail was achieved on MRI by spin echo pulse sequences with short repetition times. Bone tumors were delineated best by spin echo 1000/30 images, and soft tissue tumors by spin echo 1000/30 or inversion recovery images.     

Computed tomography or magnetic resonance for evaluating the solitary tumor or tumor-like lesion of bone?

Following an abnormal radiograph, an initial 34 patients had both computed tomography (CT) and magnetic resonance (MR) to further characterize and stage a solitary tumor. This experience determined the choice between CT and MR in evaluating the next 55 solitary tumors. The choice of examination depends on the radiologist's ability to characterize the lesion from the radiograph as to its morphology, matrix, and probable histologic nature. The anatomic location, in turn, frequently influences the ability to characterize the lesion. Lesions in long bones can almost always be successfully characterized by radiography and, in these instances, only the MR examination is required to stage the tumor. Radiographic characterization of tumors in flat bones such as the scapula, certain portions of ribs, vertebrae, and pelvis is often difficult or incomplete. In these cases, CT is the preferred initial examination, and if further staging is required to establish the relationship of the tumor to soft tissues or neurovascular structures, the MR examination is done. Because of MR's superiority in staging the tumor and CT's superiority in characterizing the lesion, the initial choice between the two examinations should depend on the radiologist's ability to characterize the lesion from the radiograph. When radiographic depiction of tumor permits assessment of its morphology, matrix and probable histologic nature, (characterization) MR ought to be the next examination solely for staging purposes. It is the anatomic location of the tumor and the radiologist's ability to characterize it that ought to govern the choice of the next examination. Surgical and histopathological findings were known in all patients in this study.     

MRI in primary intraspinal extradural hydatid disease: case report

A rare case of pathologically proven primary intraspinal extradural hydatid disease of the thoracic region with spinal cord compression is reported. The diagnosis was established preoperatively on the basis of the MRI findings. The patient underwent surgery and recovered completely. Received: 7 April 1997 Accepted: 15 July 1997