Magnetic resonance imaging of musculoskeletal soft tissue masses

The role of MR imaging in the evaluation of children with large, deep, or infiltrative soft tissue masses is to characterize and determine the extent of the lesion for treatment planning. There are a small number of soft tissue tumors with MR imaging appearances characteristic enough to allow a specific diagnosis, obviating biopsy. In the remaining cases with nonspecific imaging appearances, MR imaging is used for anatomic staging, but tissue sampling is still required for determining histology and grading.     

Should an MR scan be performed routinely after a normal clearance CT scan in the trauma patient? Experience with 59 cases

Magnetic resonance (MR) imaging is not routinely used to exclude ligamentous and other soft tissue injury in the unconscious trauma patient. In order to determine the frequency and types of soft tissue injuries detected by MR imaging but not by computed tomography (CT), we performed a retrospective investigation comparing the MR findings in 59 trauma patients, either alert or unconscious, who previously had undergone a negative clearance multislice CT study of the cervical spine. Six patients had abnormalities not identified on the CT studies, including four cases of ligamentous injury.     

The role of MR imaging in invasive cervical carcinoma

In this article the role of MR imaging in the management of cervical cancer is reviewed and illustrated. The appearance of the normal uterine cervix and of cervical carcinoma is shown. Important factors for optimal MR imaging of cervical carcinoma are reviewed. The value of MR imaging in the staging of cervical carcinoma is illustrated by showing parametrial invasion and lymph node involvement. Finally, the value of MR imaging staging is compared with clinical staging, CT staging, and surgical findings. The role of new imaging techniques, such as fast dynamic enhanced MR imaging, is described. Received: 12 April 1999; Revised: 13 July 1999; Accepted: 14 July 1999     

Masses of the tongue and floor of the mouth: findings on magnetic resonance imaging

The purpose of this study was to determine the value of MR imaging for the demonstration of masses in the tongue and floor of the mouth. Nine patients were prospectively examined with MR imaging after physical examination. Imaging protocol included T2 and contrast-enhanced and non-contrast-enhanced T1-weighted turbo spin-echo sequences, and the findings were compared with surgical and histopathological results. Histopathological examination revealed four squamous cell carcinomas, one adenoid cystic carcinoma, two tongue abscesses, and one chronic inflammatory change. The other case was diagnosed as hemangioma depending on clinical and imaging findings alone. In cases with squamous cell carcinoma, staging was done on the basis of MR imaging findings, and was found to be T4 in two cases, T3 in one case, and T2 in another. The primary role of MR imaging of the tongue and oropharynx is not to make a tissue diagnosis. Multiple deep biopsies are mandatory for the differentiation of other inflammatory and neoplastic lesions. Magnetic resonance imaging produces coronal and sagittal image planes to assess the volume and spread of the lesion and helps the surgeon determine the direction in which the biopsy should be performed. Received: 4 October 1999; Revised: 31 January 2000; Accepted: 6 April 2000     

Mediastinal myelolipoma: CT and MRI appearances

A 72-year-old man presented with a mediastinal mass on chest radiograph. Computed tomography and MR imaging showed that the mass consisted of both fatty and small nodular soft tissue components, highly suggestive of an extramedullary hematopoiesis or a myelolipoma. A CT-guided needle biopsy was next performed and confirmed the diagnosis. We discuss the CT and MR imaging appearances of this tumor and usefulness of a CT-guided needle biopsy to avoid surgery in asymptomatic patients. Received: 8 March 1999; Revised: 23 June 1999; Accepted: 25 June 1999     

Preoperative evaluation and monitoring chemotherapy in patients with high-grade osteogenic and Ewing’s sarcoma: review of current imaging modalities

Diagnostic imaging is pivotal in the initial detection, characterization, staging and post-treatment follow-up of patients with high-grade osteogenic and Ewing’s sarcoma. In the present review article, conventional and new imaging modalities are discussed with regard to the monitoring of the effect of neoadjuvant chemotherapy in such patients. Presurgical monitoring of response to chemotherapy may have an impact on modification of neoadjuvant treatment protocols, on patient selection for the performance and timing of limb-salvage surgery and on planning of radiation therapy (in non-operated Ewing’s sarcomas) and selection of postoperative chemotherapy regimens. Dynamic contrast-enhanced MR imaging, as part of a routine MR protocol, assists in the detection of the most viable parts of the tumour and serves as an initial standard for follow-up of the metabolic activity of the tumour during and after chemotherapy, both in small intraosseous tumours and in tumours with an associated soft tissue mass. In combination with selected morphological features, dynamic imaging parameters are therefore advocated for monitoring the effect of neoadjuvant chemotherapy in patients with osteogenic and Ewing’s sarcoma.     

MR Imaging of Soft Tissue Tumors: An Overview

Over the past decade, magnetic resonance (MR) imaging has been established as the most widely used examination for the detection of a suspected soft tissue mass and often for depiction of the extent and the characterization of the mass. Sensitivity of the examination for the detection of soft tissue masses is high but specificity is limited. With experience accrued over the past decade, radiologists are increasingly able to predict the histology of lesions based on MR imaging criteria. However, because of the overlap of morphologic features of benign and malignant soft tissue masses, a benign-appearing mass should not be considered benign unless the tumor can be specifically named and its histology predicted by well-established MR imaging features. When a mass is not thought to be an overt sarcoma and there is uncertainty as to whether it is benign or malignant, the tumor should be characterized as indeterminate and approached as a sarcoma until proven otherwise. This article reviews MR imaging in diagnosing and staging soft tissue masses and briefly discusses the radiologist?s approach to percutaneous biopsy of indeterminate soft tissue masses.     

Diagnosis and staging of laryngeal tumors with CT and MRI

Summary Cross-sectional imaging with CT and MRI plays an indispensable complementary role to endoscopy in the pretherapeutic workup and staging of laryngeal neoplasms. Adequate interpretation of the CT and MR images requires a thorough knowledge of the patterns of submucosal spread and familiarity with the diagnostic signs of neoplastic invasion as seen with each modality. In addition, the radiologist should be aware of the implications of imaging for staging and treatment. Both CT and MR imaging are highly sensitive for the detection of neoplastic invasion of the pre-epiglottic space, paraglottic space, subglottic region and cartilage. The high negative predictive value of both CT and MRI allows exclusion of neoplastic cartilage invasion quite reliably. The specificity of both CT and MRI is, however, limited and both methods may therefore overestimate the extent of tumor spread. Nevertheless, both cross-sectional imaging methods significantly improve the pretherapeutic staging accuracy of laryngeal tumors if used in addition to clinical examination and endoscopic biopsy. In the presence of a submucosal mass, CT and MRI play a key role for the diagnosis, as they may characterize the lesion, reliably depict its submucosal extent, and guide the endoscopist to perform deep biopsies that allow a definitive histological diagnosis.      

Rectal tumour staging: MR imaging using pelvic phased-array and endorectal coils vs endoscopic ultrasonography

The aim of this study was to compare MR imaging and endoscopic ultrasonography (EUS) for the local staging of rectal tumours. Forty-nine patients were examined on a 1.5-T MR unit using either a pelvic phased-array coil (n = 37) alone or combined with an endorectal coil (n = 12). Sagittal and axial sequences with T2-weighted fast spin-echo and axial T1-weighted spin-echo techniques were employed. The EUS technique was performed using a flexible endosonoscope. The results were compared with findings at histopathological sectioning of the specimen. The T-stage on MR correlated with histopathology in 32 of 49 patients and on EUS in 29 of 49 patients. The N-stage on MR correlated with histopathology in 22 of 49 patients and on EUS in 26 of 49 patients. Tumour penetration of the rectal wall was predicted by MR with 86 % sensitivity and 65 % specificity, and by EUS with 89 % sensitivity and 33 % specificity. Preoperative radiotherapy was administered to 40 of the patients after the examinations which may explain some of the overstaging by MR and EUS. Three patients with surgically and histopathologically confirmed invasion of neighbouring organs in the pelvis were detected preoperatively on MR but none on EUS. Tumour penetration of the rectal wall and local lymph node metastases cannot accurately be predicted with MR or EUS. Magnetic resonance, however, seems to be more useful for preoperative identification of clinically occult advanced disease. Received: 18 February 1999; Revised: 17 September 1999; Accepted: 20 September 1999     

Radiological follow-up of inverted papilloma

The aim of this study was to describe cross-sectional imaging features of recurrent papilloma of the nasal fossa and paranasal sinuses and to evaluate the role of MR and CT in the postoperative follow-up of this lesion. Magnetic resonance imaging and CT of ten patients who presented recurrence of inverted papilloma were reviewed and correlated to initial imaging, endoscopy, and surgical reports. Imaging patterns of recurrent inverted papilloma are identical to those of initial tumors and recurrence location is closely related to the site of the former lesion. Magnetic resonance is more efficient than CT for the diagnosis and evaluation of extensions. Magnetic resonance supplies the deficiencies of endoscopy in case of extensions to the frontal sinus or the lateral recess of the antrum, especially if mucosal hyperplasia or sinusitis is associated. Magnetic resonance imaging is the first imaging modality to perform in the follow-up after removal of inverted papilloma. Received: 28 April 1999; Revised: 18 November 1999; Accepted: 19 November 1999     

MR imaging of tumor and tumorlike lesions of bone and soft tissue

This review examines the role of MR imaging in the diagnosis and staging of tumors and tumorlike lesions of bone and soft tissue. For tumors of bone, the plain radiograph is not only the least expensive diagnostic test but is the most reliable predictor of the histologic nature of a given lesion. Consequently, it should be the first procedure performed and serve as the basis for determining the next step in the patient's evaluation. MR imaging is the examination of choice for staging bone tumors. CT is preferred to MR imaging only when the characteristics of the lesion are inadequately defined on plain radiographs, as may occur in flat bones. Although MR imaging is of limited value in predicting the histology of bone tumors, it is a useful tool for distinguishing round-cell tumors and metastases from stress fractures and medullary infarcts in symptomatic patients with normal radiographs. For depiction of soft-tissue masses, MR imaging is unrivaled. The histologic nature of a soft-tissue mass may, in some instances, be predicted on the basis of its MR appearance and multicentricity. Biopsy of bone and soft-tissue tumors should follow and not precede MR imaging. MR imaging reliably shows change in tumor volume after radiation or chemotherapy. It is less reliable in predicting the amount of tumor necrosis.     

The use of magnetic resonance imaging in the evaluation of bone and soft-tissue tumors

We believe that MR imaging should follow plain films in the imaging analysis of soft-tissue tumors and bone tumors suspected of malignancy. MR imaging is primarily useful in tumor staging, although it may aid in diagnosis and the detection of recurrent or residual disease. Gd-DTPA and MR spectroscopy are currently being evaluated in many medical centers; their utility in the work-up and management of tumors of bone and soft tissue has yet to be determined.     

Value of fluid-attenuated inversion recovery sequences in early MRI of the brain in neonates with a perinatal hypoxic-ischemic encephalopathy

The aim of our study was to assess the usefulness of fluid-attenuated inversion recovery (FLAIR) sequences in comparison with conventional spin-echo and inversion MR imaging in neonates for evaluation of myelination and for detection of hypoxic-ischemic brain injury. We reviewed early MR scans of 18 neonates with suspected hypoxic-ischemic brain damage. Myelination could be evaluated with confidence using conventional MR imaging in all but 2 infants; however, the presence of myelin was very difficult to assess on FLAIR images. Overall, 53 lesions or groups of lesions were identified. The FLAIR technique was more sensitive in 11 of the lesions; especially (pre)cystic lesions could be identified much better and more cysts were found. Conventional MR imaging failed to identify 2 of the lesions and was more sensitive in 14 of the lesions; especially punctate hemorrhages and lesions in basal ganglia or thalami could be better determined. The FLAIR technique missed 3 of these lesions. In the remaining 28 lesions conventional MR and FLAIR images were equally diagnostic. The FLAIR technique and conventional MR imaging are complementary in detecting early sequelae of hypoxic-ischemic brain injury in neonates. The FLAIR technique is not suitable for assessing myelination of the neonatal brain; therefore, FLAIR cannot replace conventional MR imaging. Received: 11 January 2000; Revised: 10 April 2000; Accepted: 10 April 2000     

Contrast-enhanced three-dimensional helical CT for soft tissue tumors in the extremities

Objective. To evaluate the ability of contrast-enhanced three-dimensional (3D) helical computed tomography (CT) to image soft tissue tumors in the extremities. Design and patients. Forty-five consecutive patients with soft tissue tumors in the extremities were examined (mean age 46.2 years; 24 females, 21 males). Twenty-five patients had benign lesions and 20 had malignant lesions. All the patients underwent contrast-enhanced 3DCT scanning and magnetic resonance (MR) imaging preoperatively. All patients were surgically treated. Spiral CT scanning was performed with intravenous contrast enhancement. 3D reconstruction images were produced after thresholding, using Active-Windows (version 2.0, General Electric, Milwaukee, WI) software. 3DCT findings were compared in a masked fashion with the MR imaging and surgical findings regarding bone and major vessel invasion by the tumors. Results. Forty-four of 45 tumors were satisfactorily imaged for the interpretation of their size, location and relationship to the skeleton and major vessels. One malignant tumor was judged on 3DCT to invade the major vessel, but the vessel proved to be normal at surgery. Conclusions. Contrast-enhanced 3D helical CT can be used for the evaluation of soft tissue tumors in the extremities, for preoperative surgical planning. Received: 14 August 2000 Revision requested: 28 November 2000 Revision received: 29 December 2000 Accepted: 1 February 2001     

Gleno-humeral instabilities

The purpose of this review is to highlight the most efficient imaging exploratory techniques depicting shoulder instability, to describe its various forms and to point out the findings which can simulate instability. In anterior recurrent dislocation, surgery is indicated and the procedure essentially depends on the importance of glenoid rim lesions. In this case, a standard X-ray evaluation is usually sufficient. The CT arthrography or MRI techniques give more specific details as to the severity of the lesions, particularly soft tissues alterations; however, these data do not alter standard therapeutic protocol. In fixed posterior dislocations, CT scan represents the most pertinent technique to evaluate the size of the humeral head defect and to determine the therapeutic follow-up. In subtle forms of instability, diagnosis or instability direction are not clearly assessed clinically and standard X-ray evaluation is usually unremarkable. In this case, further exploration, such as CT arthrography, MR imaging or MR arthrography, are recommended to confirm the diagnosis of instability and to evaluate its direction. The technique of choice is undoubtedly MR arthrography. Atraumatic voluntary painless subluxations associated with hyperlaxity of the shoulder do not require any specific exploratory method because the findings are generally limited to a capacious axillary pouch. Received: 28 September 1998; Revised: 21 January 1999; Accepted: 22 March 1999     

MRI of breast tumors

Breast MRI is increasingly used as an adjunct to conventional imaging modalities, particularly in diagnostic problem cases, but also for pre-operative staging. It is an extremely sensitive technique, with relatively limited specificity. To avoid both, false-positive, but particularly false-negative diagnoses, it is imperative to be familiar with the varying MRI appearance of benign and malignant breast tumors. This review serves to give an overview of the different criteria that can be used for differential diagnostic purposes. Moreover, practical guidelines are given to help with the adequate management of enhancing lesions.     

MR Imaging features of pelvic mucinous carcinomas

Mucinous carcinomas in the pelvis differ from non-mucinous tumors because of the differences in clinical outcome and imaging appearance. Mucinous rectal carcinomas, for example, are known to be higher in stage at the time of the diagnosis because they are more likely to be infiltrative and show a greater tendency for recurrence. These factors may lead to a poorer prognosis in patients with the mucinous as compared with non-mucinous carcinomas. Mucinous carcinomas of all types typically show high signal intensity on T2-weighted MR images, and therefore mimic other conditions such as necrotic tumors, fluid collections, cysts, or liver hemangiomas. To familiarize readers with the MRI appearance, and to avoid pitfalls, this paper illustrates the MRI features of the mucinous adenocarcinomas in various pelvic organs. Received: 8 February 1999; Revised: 7 October 1999; Accepted: 10 January 2000     

Fat necrosis

 We report the MR appearance of a case of subcutaneous fat necrosis, which is a previously unreported etiology for knee mass. The role of MR imaging in differentiating fat necrosis from other causes of soft tissue masses is discussed. We conclude that MR characteristics of subcutaneous fat necrosis are typical and allow its differentiation from other types of soft tissue lesions.     

CT diagnosis of diaphragm injuries

Admission supine chest radiographs are the initial and most commonly performed imaging study to evaluate the thorax following trauma. Whenever the chest radiograph is ambiguous or suggestive of a diagnosis of acute diaphragmatic injury, CT is the next study of choice since it is generally available and often used to examine other body regions of the polytraumatized patient. CT is usually diagnostic, particularly if supplemented by multiplanar reformations obtained using a thin slice thickness. Currently MR imaging is used at our trauma center to evaluate the diaphragm in patients with an indeterminate diagnosis after spiral CT. A limited MR imaging examination with T1-weighted sagittal and coronal imaging has been extremely accurate in establishing or excluding diaphragm injury.     

Local recurrence of rectal cancer: MR imaging before and after oral superparamagnetic particles vs contrast-enhanced computed tomography

The aim of this study was to compare three imaging strategies for the diagnosis of local recurrence of rectal cancer: (a) MR imaging; (b) MR imaging after administration of enteral superparamagnetic particles (Ferristene); and (c) contrast-enhanced CT. Seventeen patients with previous surgery for rectal cancer were examined, 12 patients with local tumour recurrence in the pelvis and 5 patients with postoperative changes. Pelvic multi-coil MR imaging before and after oral administration of superparamagnetic contrast medium [Abdoscan (Ferristene USAN), Nycomed-Amersham, Liding?, Sweden] as well as abdominal and pelvic CT was performed in all patients. The examinations were independently evaluated by three different radiologists. The general effect of the oral MR contrast medium, the delineation of normal and pathological structures as well as confidence in the diagnosis were registered on a visual analog scale (VAS). The diagnosis according to MR before and after oral contrast medium, and CT, was compared, in 16 patients, with the final diagnosis which was verified by biopsy (n = 3), surgery (n = 6), clinical follow-up (n = 4) and by follow-up with MR or CT (n = 3). No significant improvement in MR image quality was found after enteral contrast medium. The post-contrast MR diagnosis was not changed in any of the patients. The diagnosis on MR correlated with the final diagnosis in 12 of 16 patients (sensitivity 91%, accuracy 62%) and the diagnosis on CT in 11 of 16 patients (sensitivity 82 %, accuracy 56 %). The radiologists' "confidence" in the diagnosis and the degree of accordance with the final diagnosis did not score higher on MR after than before oral contrast administration; however, the accordance with the final diagnosis scored better on MR than on CT. No advantages of orally administered superparamagnetic contrast medium were observed in the examined patient group. Magnetic resonance is preferable to CT in diagnosing local tumour recurrence.