Diffusion restriction in a superficial breast lesion

OBJECTIVE

To report the imaging findings of a 22-year-old Asian woman with a freely movable retro-areolar nodule in the right breast, first noticed after a holiday in The Philippines.

MATERIAL AND METHODS

We preformed clinical examination, mammography and ultrasound with color Doppler imaging. A differential diagnosis of epidermal inclusion cyst, complex cyst, well demarcated carcinoma and echinococcus cyst was proposed. For further differential diagnosis, a MRI of the breasts was performed on a 1.5 superconducting system, with a bilateral breast coil. T2- and T1 weighted images, followed by axial echo-planar diffusion-weighted MRI (DW-MRI) were performed with b values of 0, 500, and 1000 mm2/s (trace images and ADC maps).

RESULTS

The high signal intensity on T2 weighted images confirmed the cystic character of the lesion. The high signal intensity on T1 FS weighted images can be seen in complex cysts and inclusion cysts, but is less likely in an echinococcus cyst. On DW-MRI there is a marked diffusion restriction in the nodule, which can be seen in complex cysts and inclusion cysts. A well demarcated carcinoma is less likely, unless a tumour with a very high cellularity. Because neither carcinoma nor echinococcus cyst could be ruled out, a surgical excision was performed. Pathological examination revealed normal squamous epithelium with stratification and lamellated keratin, consistent with an epidermal inclusion cyst.

CONCLUSION

We argue that in selected cases DW-MRI can be useful to narrow the differential diagnosis and notable differentiate epidermal inclusion cysts from echinococcus cysts.

MR mammography is useful in the preoperative locoregional staging of breast carcinomas with extensive intraductal component

PURPOSE

To determine the role of magnetic resonance (MR) mammography in detection and assessment of extent of tumors with extensive intraductal component (EIC+).

MATERIAL AND METHODS

In a prospective study, 233 consecutive women with a suspicious lesion underwent preoperative MR mammography and 209 invasive ductal carcinomas were detected. We studied the prediction of intraductal spread on mammography (MX), ultrasound (US) and MR. We compared the size of the total lesion on MX, US and MR and correlated it with histopathology. Enhancement patterns on MR were described.

RESULTS

Of 209 invasive ductal carcinomas, 50 were EIC+ (24%). MX predicted intraductal spread in EIC+ carcinomas in 48.5%, US in 34.2% and MR in 68%. Compared to MX and US, MR was best in assessment of total tumor size. On MR, ductal spread in EIC+ tumors presented as ductal or linear enhancement, long spicules, a regional enhancing area or nodules adjacent to a mass.

CONCLUSION

MR had the highest sensitivity to predict intraductal spread and was superior in assessing total tumor size.

Chest MSCT acquisition and injection protocols

The past decade there has been an enormous advance in imaging technology, most obvious in the field of magnetic resonance imaging (MRI) and computed tomography (CT). Today nearly every radiology department has a multislice CT (MSCT) available for routine imaging, many of which are increasingly being replaced by last generation 16- and 64-slice CT scanners. However, the use of fast CT scanners requires a better insight in acquisition and contrast media injection protocols in order to achieve the best possible result. It is the aim of this article to give a review of the basic principles of CT protocol design for the chest and the kinetics of contrast media injection.

Campylobacter jejuni-induced acute transverse myelitis

STUDY DESIGN

Case report.

SETTING

University Hospital of Antwerp, tertiary referral hospital of the University of Antwerp, Edegem, Belgium.

CASE REPORT

Campylobacter jejuni infection is related to various syndromes in which the peripheral nervous system is involved. An immune response is triggered through molecular mimicry between gangliosides of the peripheral nervous system and lipo-oligosaccharides of C. jejuni. We report a case of a previously healthy 17-year-old girl, who developed clinical manifestations of acute transverse myelitis (ATM) 7 days after a culture-proven C. jejuni enteritis. High titres of serum IgG antibodies to the ganglioside GM1 were found in the acute phase of disease, which decreased with clinical recovery. These antibodies cross-reacted with C. jejuni lipo-oligosaccharides, indicating that C. jejuni infections may induce ATM.

CONCLUSIONS

Only a few cases of C. jejuni infection associated with demyelination of the central nervous system or spinal cord have been described. Physicians should be aware that C. jejuni might be another cause of transverse myelitis.

Functional imaging using computational fluid dynamics to predict treatment success of mandibular advancement devices in sleep-disordered breathing

Mandibular advancement devices (MADs) have emerged as a popular alternative for the treatment of sleep-disordered breathing. These devices bring the mandibula forward in order to increase upper airway (UA) volume and prevent total UA collapse during sleep. However, the precise mechanism of action appears to be quite complex and is not yet completely understood; this might explain interindividual variation in treatment success. We examined whether an UA model, that combines imaging techniques and computational fluid dynamics (CFD), allows for a prediction of the treatment outcome with MADs. Ten patients that were treated with a custom-made mandibular advancement device (MAD), underwent split-night polysomnography. The morning after the sleep study, a low radiation dose CT scan was scheduled with and without the MAD. The CT examinations allowed for a comparison between the change in UA volume and the anatomical characteristics through the conversion to three-dimensional computer models. Furthermore, the change in UA resistance could be calculated through flow simulations with CFD. Boundary conditions for the model such as mass flow rate and pressure distributions were obtained during the split-night polysomnography. Therefore, the flow modeling was based on a patient specific geometry and patient specific boundary conditions. The results indicated that a decrease in UA resistance and an increase in UA volume correlate with both a clinical and an objective improvement. The results of this pilot study suggest that the outcome of MAD treatment can be predicted using the described UA model.

MRI in patients with otovestibular complaints of unknown origin

OBJECTIVES

The place of MRI in the diagnostic work-up of patients with bilateral perceptive hearing loss, tinnitus and vertigo is under discussion. The purpose of this study is to investigate the role of MRI in patients with otovestibular and cranial nerve complaints of unknown aetiology.

METHODOLOGY

After thorough otologic examination, 430 patients were consecutively referred for an MR examination of the cerebellopontine angle.

RESULTS

The detection rate for essential lesions was 4.9%. Two groups of retrocochlear lesions were frequently observed: central WMLs/atrophy and neurovascular conflict affecting a cranial nerve.

CONCLUSIONS

MR imaging of the cerebellopontine angle, fossa posterior and petrous bones makes it possible to observe abnormalities of the vestibulocochlear nerve and inner ear. Additional T2-weighted FSE images of the whole brain make it possible to evaluate the occurrence of early central lesions. This imaging protocol can diagnose essential lesions relating directly to the complaint in 4.9% of the patients with hearing loss, subjective tinnitus or vertigo. We frequently observed two groups of lesions of uncertain significance in our study population. WMLs are present in 50% of patients with a mean age of 59 years. In the younger subpopulation aged under 51 years the prevalence of WMLs is 24%. It remains unclear whether these lesions can be accounted for by the diversity of symptoms with which the patients presented. In addition, we found a high number of neurovascular conflicts involving different cranial nerves.

Functional MRI of the cervical spinal cord on 1.5 T with fingertapping: to what extent is it feasible?

INTRODUCTION

Until recently, functional magnetic resonance imaging (fMRI) with blood oxygen level-dependent (BOLD) contrast, was mainly used to study brain physiology. The activation signal measured with fMRI is based upon the changes in the concentration of deoxyhaemoglobin that arise from an increase in blood flow in the vicinity of neuronal firing. Technical limitations have impeded such research in the human cervical spinal cord. The purpose of this investigation was to determine whether a reliable fMRI signal can be elicited from the cervical spinal cord during fingertapping, a complex motor activity. Furthermore, we wanted to determine whether the fMRI signal could be spatially localized to the particular neuroanatomical location specific for this task.

METHODS

A group of 12 right-handed healthy volunteers performed the complex motor task of fingertapping with their right hand. T2*-weighted gradient-echo echo-planar imaging on a 1.5-T clinical unit was used to image the cervical spinal cord. Motion correction was applied. Cord activation was measured in the transverse imaging plane, between the spinal cord levels C5 and T1.

RESULTS

In all subjects spinal cord responses were found, and in most of them on the left and the right side. The distribution of the activation response showed important variations between the subjects. While regions of activation were distributed throughout the spinal cord, concentrated activity was found at the anatomical location of expected motor innervation, namely nerve root C8, in 6 of the 12 subjects.

CONCLUSION

fMRI of the human cervical spinal cord on an 1.5-T unit detects neuronal activity related to a complex motor task. The location of the neuronal activation (spinal cord segment C5 through T1 with a peak on C8) corresponds to the craniocaudal anatomical location of the neurons that activate the muscles in use.

The value of magnetic resonance imaging in the differentiation between malignant peripheral nerve-sheath tumors and non-neurogenic malignant soft-tissue tumors

OBJECTIVE

To assess the sensitivity and specificity of MRI criteria in the differentiation between malignant peripheral nerve sheath tumors (MPNST) and non-neurogenic malignant soft-tissue tumors (MSTT).

DESIGN AND PATIENTS

MRI examinations of 105 patients with pathologically proven malignant soft-tissue lesions (35 MPNST and 70 MSTT) were retrospectively reviewed, the reviewers being unaware of the pathological diagnosis. Using a standardized protocol, the tumors were evaluated for multiple parameters regarding morphology and appearance on different sequences before and after gadolinium contrast administration (location, distribution, delineation, homogeneity, size, shape, relationship to bone and neurovascular bundle, intralesional hemorrhage, necrosis, perilesional edema, lymphangitis and signal intensities). Results were compared using a chi-square or Fisher's exact test.

RESULTS

MRI findings suggestive of MPNST (p<0,05) were intermuscular distribution, location on the course of a large nerve, nodular morphology, and overall non-homogeneity on T1-weighted images, T2-weighted images and T1-weighted images after gadolinium contrast injection. MRI findings in favor of MSTT were intramuscular distribution, ill-delineated appearance of more than 20% of the lesion's circumference, and presence of intralesional blood vessels, perilesional edema and lymphangitis. There is no significant difference for degree and pattern of enhancement after gadolinium contrast injection, nor for presence of bone involvement or cystic or necrotic areas.

CONCLUSION

MRI provides several features that contribute to the differentiation between MPNST and non-neurogenic malignant soft-tissue tumors. MRI findings suggestive of MPNST should be helpful to pathologists in the strategy for further examination.

Imaging of malignant bonetumors

Diagnostic imaging plays a pivotal role in the initial detection, characterization, pre-operative assessment and long term follow-up of malignant bone tumors. The purpose of this brief review is to discuss the specific role of the different imaging modalities in the diagnostic work-up of malignant bone tumors. The imaging features, with emphasis on standard radiography, allowing differentiation, of malignant bone tumors, will be highlighted.

Tuberculosis: epidemiology, manifestations, and the value of medical imaging in diagnosis

Mycobacterial infections have been shown to be increasing in number worldwide, mainly due a global increase in developing countries, the increased number of patients with HIV infection and AIDS disease worldwide, an increasing number of elderly patients and the emergence of multidrug resistant tuberculosis. Inhalation is the predominant pathway of Mycobacterium tuberculosis (M. tuberculosis) infection, making pulmonary tuberculosis the most common form of tuberculosis. Tuberculosis may arise either from a recent infection with M. tuberculosis, or from the reactivation of dormant bacilli, years or decades after initial infection. Extrapulmonary tuberculosis mainly results from reactivation of a tuberculous focus after hematogenous dissemination or lymphogenous spread from a primary, usually pulmonary focus. Tuberculosis may demonstrate a variety of radiological features depending on the organ site involved and may mimick other pathologies. The final diagnosis of tuberculous disease mainly depends on the detection of the causative organism on histopathological examination, culture and polymerase chain reaction-based assay for mycobacterial DNA on material obtained during bronchoscopic washings, fine needle aspiration cytology (FNAC) or biopsy.

Proceedings of the European Society of Musculoskeletal Radiology (ESSR) training module, Antwerp, 20-21.01.05. Part two: bone tumors. Benign bone lesions: characteristic imaging features

Benign bone lesions are a fairly common finding in radiology practice. Often, the combination of patient's age and plain radiographic findings are sufficient for diagnosis and obviates the need for further imaging. Generally the following parameters should be assessed in the evaluation of a bone lesion: clinical features, age of the patient, location, size, pattern of bone destruction, cortical involvement, zone of transition, sclerotic margination and matrix calcification. Cross sectional imaging, such as CT or MRI complements radiography, especially in complex anatomical sites. This article reviews the spectrum of clinical and imaging appearances of the most common benign bone tumors.

Imaging of soft tissue tumors: general imaging strategy and technical considerations

This paper reviews the imaging strategy and protocol for detection, grading and staging, and posttherapeutic follow-up of soft tissue tumors (STT), used in our institution. The role of each imaging technique, with emphasis on magnetic resonance imaging, is highlighted.

Imaging of vascular soft tissue tumors

Most tumors of the vascular system are benign, cutaneous or subcutaneous lesions that are usually readily diagnosed without significant differential diagnosis. On the other hand, lesions that arise in deep soft tissues have to be differentiated from malignant neoplasms. In these cases, further imaging work-up is necessary for local staging and planning therapy. Vascular lesions of intermediate malignancy and malignant vascular tumors are very rare and demonstrate nonspecific imaging findings. This manuscript aims to give a brief overview of vascular soft-tissue tumors and to discuss the imaging appearances.

Imaging of joint tumors

The paper gives an overview of the present nosological classification and imaging features of synovial tumors and tumor-like conditions of joints. The merits of each imaging technique will be emphasized.

Imaging of lipomatous soft tissue tumors

The purpose is to give an overview of the imaging features of benign and malignant lipomatous tumors. Imaging characteristics which are helpful in the differential diagnosis between benign and malignant subtypes are highlighted.

Imaging features of peripheral neurogenic tumors

Peripheral nerve sheath tumors (PNST) include schwannoma, neurofibroma and malignant peripheral sheath tumors. All neurogenic tumors share the same imaging characteristics, including fusiform shape, low attenuation on CT, fascicular sign, split fat sign and associated muscle atrophy. The aim of this article is to give a comprehensive overview of peripheral nerve tumors and to discuss the imaging characteristics that distinguish these masses.

Prevalence, extension and characteristics of fluid-fluid levels in bone and soft tissue tumors

The purpose of this study was to determine the prevalence, extension and signal characteristics of fluid-fluid levels in a large series of 700 bone and 700 soft tissue tumors. Out of a multi-institutional database, MRI of 700 consecutive patients with a bone tumor and MRI of 700 consecutive patients with a soft tissue neoplasm were retrospectively reviewed for the presence of fluid-fluid levels. Extension (single, multiple and proportion of the lesion occupied by fluid-fluid levels) and signal characteristics on magnetic resonance imaging of fluid-fluid levels were determined. In all patients, pathologic correlation was available. Of 700 patients with a bone tumor, 19 (10 male and 9 female; mean age, 29 years) presented with a fluid-fluid level (prevalence 2.7%). Multiple fluid-fluid levels occupying at least one half of the total volume of the lesion were found in the majority of patients. Diagnoses included aneurysmal bone cyst (ten cases), fibrous dysplasia (two cases), osteoblastoma (one case), simple bone cyst (one case), telangiectatic osteosarcoma (one case), "brown tumor" (one case), chondroblastoma (one case) and giant cell tumor (two cases). Of 700 patients with a soft tissue tumor, 20 (9 males and 11 females; mean age, 34 years) presented with a fluid-fluid level (prevalence 2.9%). Multiple fluid-fluid levels occupying at least one half of the total volume of the lesion were found in the majority of patients. Diagnoses included cavernous hemangioma (12 cases), synovial sarcoma (3 cases), angiosarcoma (1 case), aneurysmal bone cyst of soft tissue (1 case), myxofibrosarcoma (1 case) and high-grade sarcoma "not otherwise specified" (2 cases). In our series, the largest reported in the literature to the best of our knowledge, the presence of fluid-fluid levels is a rare finding with a prevalence of 2.7 and 2.9% in bone and soft tissue tumors, respectively. Fluid-fluid levels remain a non-specific finding and can occur in a wide range of bone and soft tissue tumors, both benign and malignant. Therefore, they cannot be considered diagnostic of any particular type of tumor, and the diagnosis should be made on the basis of other radiological and clinical findings.