Magnetic resonance imaging of primary skeletal neoplasms

The primary role of magnetic resonance (MR) imaging of skeletal neoplasms is that of staging. Understanding the staging process and selection of the proper imaging planes and pulse sequences is essential for proper staging. To date, image features are not specific for histologic type. In addition, there are still pitfalls with MR imaging for evaluating recurrent tumor or following therapeutic response to treatment. Dynamic gadolinium studies and spectroscopy may improve the future overall specificity for MR imaging.     

Magnetic resonance imaging in breast cancer staging

For many solid carcinomas, high-resolution cross-sectional imaging has changed cancer staging, the evaluation of therapeutic response, the detection of recurrence, and even how therapy is selected and performed. Such imaging has not yet had similar effects on breast cancer. Evaluations of therapeutic response in breast carcinomas have been impeded by the current limited methods of evaluating breast tumor size and extent: clinical palpation, ultrasonography, and mammography. The use of magnetic resonance imaging (MRI) of the breast in the evaluation of breast tumors brings the advantages of high-resolution cross-sectional imaging to breast cancer staging and treatment evaluation and is likely to greatly enhance research efforts in this complex disease. MRI of the breast has evolved to be the most accurate noninvasive technique for local staging of breast cancer. MRI is most accurate in measuring tumor size and detecting multicentric disease. These staging characteristics affect the selection of therapy and initial determination of prognosis; therefore, MRI of the breast can change the assessment of fundamental parameters on which treatment is selected. Because clinical trials of new cancer treatments are predicated on proper and accurate characterization of the tumor, MRI also should affect how clinical trials are performed and evaluated.     

Magnetic resonance imaging in the staging of solitary plasmacytoma of bone

PURPOSE: To assess prospectively the role of magnetic resonance (MR) imaging in the staging of patients with a solitary bone plasmacytoma (SBP). PATIENTS AND METHODS: Twelve consecutive patients with an apparent SBP underwent MR imaging of both the primary tumor and the thoracic and lumbosacral spine to seek additional foci of marrow involvement that might have been undetected by standard skeletal survey. All patients received megavoltage irradiation (total dose, 40 Gy) to the primary lesion. RESULTS: MR imaging of the thoracic and lumbosacral spine showed additional foci of marrow replacement in four of 12 patients, with signal characteristics identical to those of the primary tumor. In all four patients, the abnormal protein persisted at greater than 50% of the pretreatment value following radiation treatment. In contrast, the myeloma protein disappeared or was reduced by greater than 50% in five of the six patients with secretory disease and without additional marrow abnormalities. One of four patients progressed to multiple myeloma 10 months after diagnosis with new lesions on conventional radiographs in the same areas as detected previously by MR imaging. CONCLUSION: Four of 12 patients considered to have a SBP by standard criteria may have been understaged, because MR imaging showed additional marrow abnormalities consistent with myeloma. MR imaging of the spine may contribute to the initial staging of SBP, especially since some patients may be cured with radiotherapy.     

Diagnosis and staging of pancreatic neoplasms

The relative value of current approaches to the diagnosis and staging of pancreatic cancer is discussed. A rational sequence of testing is recommended based on the clinical presentation of the patient and the local institutional expertise and facilities that are available.     

Magnetic resonance cholangiopancreatography: a novel approach to the evaluation of suspected pancreaticobiliary neoplasms

BACKGROUND: Magnetic resonance cholangiopancreatography (MRCP) is a new noninvasive diagnostic method for pancreaticobiliary (PB) imaging without endoscopy, sedation, or iodinated contrast. The purpose of this study was to evaluate the ability of MRCP to depict pancreatic and biliary ductal anatomy compared to that of endoscopic retrograde cholangiopancreatography (ERCP) and to evaluate the ability of MRCP to accurately diagnose PB neoplasms. METHODS: Twenty patients had MRCP, and 17 also had ERCP. All studies were read prospectively by experienced reviewers blinded to other imaging data. Pathologic diagnosis was made in all patients. RESULTS: Bile duct dilatation seen by ERCP in 14 of 17 patients was correctly identified by MRCP in all 14 patients, and normal ducts were correctly identified by MRCP in the other 3 patients. The pancreatic duct was visible on MRCP in the pancreatic head in 17 of 20 patients, the body in 17 of 20 patients, and the tail in 15 of 20 patients. At ERCP, pancreatic duct dilatation was present in 11 cases and was identified by MRCP in 10 of them. Eighteen of 20 patients had malignant PB neoplasms. MRCP indicated PB neoplasm in 19 patients. Seventeen of these 19 patients had histologically confirmed malignant neoplasms pathologically, whereas 2 had benign pathology (both chronic pancreatitis). Among the 17 patients who also had ERCP, MRCP and ERCP correctly agreed on a final diagnosis of malignant neoplasm in 14 cases. In the three cases in which MRCP and ERCP disagreed on a final diagnosis, MRCP was correct in one and incorrect in two. CONCLUSIONS: MRCP can accurately and noninvasively delineate PB ductal anatomy and diagnose PB neoplasms comparably to ERCP. MRCP is an interesting new noninvasive method for evaluating patients with suspected PB neoplasms.     

Magnetic resonance imaging of the shoulder

MRI has rapidly become a commonly used technique for evaluation of the shoulder. It provides a wealth of information regarding the entire shoulder girdle, and it is the most accurate noninvasive method available for imaging the rotator cuff. There have been numerous technical improvements in MRI in the relatively short time that clinical MRI has been in existence. Further refinements in design, new imaging sequences, and additional clinical experience should help to increase the accuracy and flexibility of this imaging modality.     

Magnetic resonance imaging of the wrist

MR imaging of the wrist has the unique capability of simultaneously demonstrating bone and soft tissue structures. Its exquisite sensitivity for detecting bone marrow edema makes it and ideal screening tool for diagnosing radiographically occult osseous injuries and areas of AVN. This, together with its ability to provide a comprehensive, non-invasive assessment of the ligaments, tendons, nerves, and components of the TFC make MRI a very powerful tool for evaluating patients with wrist pain of uncertain etiology. Its exact role in the work-up of these patients has not been entirely established, but with further advances in technology and the radiologist's understanding of wrist anatomy and pathology, MRI is assuming a more central role in this clinical setting.     

Magnetic resonance angiography of the abdomen

The applications of abdominal MR angiography have been slow as compared with its applications in the head and neck mainly because of greater technical difficulties in dealing with respiratory motion and the use of the body coil, which has a poorer signal-to-noise ratio than head or surface coils. Further work is needed to reduce motion sensitivity and improve spatial resolution. Flow contrast and depiction of slowly flowing blood could be improved with the use of intravascular contrast agents. 52MR angiography is the imaging method of choice in the evaluation of the portal venous system, systemic veins, and aortic disease. With further technical improvements, it seems likely that applications of MR angiography will also be extended to smaller vessels.     

Magnetic resonance imaging]

During the last ten years substantial improvement of hardware and software used for the construction of MRI scanners has made available MRI sequences with high temporal and spatial image resolution. Therefore, MR imaging has become an excellent tool and in certain cases the gold standard for the evaluation of cardiovascular diseases. Primary indications for cardiovascular MRI include the assessment of aortic diseases, the arrhythmogenic right ventricle, surgically corrected congenital heart diseases, pericardial disease, intra- and paracardiac tumors and quantification of ventricular function and volumes and myocardial mass. Secondary indications include hypertrophic and dilative cardiomyopathies, valvular and ischemic heart disease. MRI is a totally noninvasive diagnostic technique which is safe and without known harmful potential to biological tissue. The wide diagnostic spectrum providing anatomical, geometrical functional and biochemical information cannot be accomplished by any other diagnostic method.     

Magnetic resonance imaging of the female pelvis

Evaluation of pelvic pathology is an important part of most radiology practices. Magnetic resonance imaging (MRI) has proven itself to be a useful and cost-effective method in evaluating many of these diseases. This article reviews appropriate MR imaging techniques and findings of common gynecologic disorders. Uterine pathology is categorized into congenital anomalies, benign lesions (leiomyomas, adenomyosis, endometrial polyps, and nabothian cysts), and malignancies (endometrial and cervical carcinoma). Adnexal pathology reviewed includes endometriosis, polycystic ovaries, teratomas, and benign and malignant ovarian epithelial tumors.     

Magnetic resonance imaging of the olfactory apparatus

The magnetic resonance imaging visualization of the olfactory apparatus is reported in this article. We used a superconductor-type magnetic resonance device (Siemens Magnetom H15 (1.5 T) with a surface coil. The subjects were patients with posttraumatic anosmia. The olfactory bulbs were clearly visualized in the frontal plane magnetic resonance images, the olfactory bulbs and the foramina of the cribriform plate were visualized in the sagittal section, and the olfactory bulbs, tracts, and other structures were visualized in the coronal sections. The olfactory nerves could not be seen.     

Magnetic resonance features of the enigmatic oligodendroglioma

RATIONALE AND OBJECTIVES: The authors characterize magnetic resonance (MR) features of oligodendroglioma that permit diagnosis. These features may be used to guide MR stereotactic biopsies. METHODS: Fifteen patients with mixed oligodendroglioma and four with pure oligodendroglioma were studied on a 1.5-tesla MR unit with contrast and also by computed tomography (CT). All patients had their diagnosis confirmed by light and electron microscopy, and by immunohistochemical staining. RESULTS: The most characteristic finding was a honeycomb tumor matrix (4 of 19) in oligodendroglioma. The most common finding was an amorphous pattern (12 of 19) and the least common was a large cystic pattern (3 of 19). Contrast enhancement most commonly was minimal and dot-like or lacy in appearance (11 of 19), or absent (5 of 19). Calcification was present in the majority (11 of 19). CONCLUSIONS: The honeycomb and stippled amorphous patterns reflect the cytoarchitecture of oligodendroglioma and were the most characteristic MR features. The amorphous pattern was the most commonly encountered pattern. There was a wider range of imaging findings on MR compared with CT; the flocculent calcification on CT was typical, but it was not always detected on MR. Including these characteristic areas that appear along the path of the stereotactic biopsy may ensure a correct diagnosis of oligodendroglioma because it most often is seen with another tumor, usually of the astrocytic family. Identifying the oligodendrogliomatous portion of the tumor will influence the therapy. No differences could be found in the MR appearance or biologic behavior of pure versus mixed oligodendrogliomas.     

Magnetic resonance imaging arthrography of the ankle

Magnetic resonance imaging (MRI) arthrography of the ankle is a useful diagnostic modality in the detection and staging of lateral ankle ligament tears, particularly in patients who fail to respond to conservative management. MRI arthrography also may be helpful in determining the extent of ligamentous injury in professional athletes, for whom immediate surgical repair may be the initial treatment. Preoperative planning is optimized with MRI arthrography. Frequently, alternative diagnoses may be made for conditions that can simulate lateral ligamentous injury, thus obviating the need for diagnostic arthroscopy.     

Magnetic resonance imaging based digitally reconstructed radiographs, virtual simulation, and three-dimensional treatment planning for brain neoplasms

Currently, patients with brain neoplasms must undergo both computed tomography (CT) and magnetic resonance (MR) imaging to take advantage of CT's density information and MR's soft tissue imaging capabilities. A method has been developed that allows virtual simulation, digitally reconstructed radiographs (DRRs), and 3-D treatment planning of patients with brain neoplasms to be generated using only one T1-weighted MR data set. DRRs of an anthropomorphic RANDO head phantom were generated using MR and CT imaging. The MR based DRRs provided structural information equivalent to CT based DRRs. The spatial linearity of CT and MR image sets was evaluated by measuring the percent distortion and spatial error. There was no statistical difference in spatial linearity or accuracy between the CT and MR image sets. MR and CT based treatment planning were compared using a variety of different treatment accessories, field sizes, photon energies, and gantry positions. Doses at various points throughout the head phantom were used as comparison points between CT based heterogeneous, CT based homogenous, and MR based homogenous treatment planning of the head phantom. Lithium fluoride thermoluminescent dosimeters were used to verify the dosimetric accuracy of MR based treatment planning by taking measurements at these points. For treatment plans with fields that pass through large air cavities, such as the maxillary sinus, homogenous treatment planning produces unacceptable dosimetric error (2%-4%). For treatment plans with fields that pass through the skull, MR homogenous treatment planning can be used with a dosimetric accuracy of +/- 2%.