Central nervous system: review of clinical use of contrast media.

The clinical utility of intravenous contrast administration for magnetic resonance imaging in neoplastic disease of the brain, non-neoplastic disease of the brain, and in disease of the spine is reviewed. Magnetic resonance imaging (MRI) is the modality of choice for the evaluation of most suspected intracranial and spinal pathology. Contrast use substantially improves lesion detection and differential diagnosis. Applications are discussed in neoplastic disease, infection, vascular disorders, demyelinating disease, and trauma (specifically including in the spine disk herniation). Gadolinium chelates play as important a role in magnetic resonance imaging as do iodinated agents in computed tomography. Contrast administration facilitates time-efficient and cost-effective diagnosis.

A multisite phase III study of the safety and efficacy of a new manganese chloride-based gastrointestinal contrast agent for MRI of the abdomen and pelvis.

The purpose of this study was to evaluate the safety and efficacy of a manganese chloride-based oral magnetic resonance (MR) contrast agent during a Phase III multisite clinical trial. Two hundred seventeen patients were enrolled who were already scheduled for MRI of the abdomen and/or pelvis. In this group of patients, it was postulated that the use of an oral agent would better allow discrimination of pathology from bowel. Patients with known gastrointestinal pathology including peptic ulcer disease, inflammatory bowel disease, obstruction, or perforation were excluded to minimize confounding variables that could affect the safety assessment. Of these 217 patients, 18 received up to 900 mL of placebo, and 199 patients were given up to 900 mL of a manganese chloride-based oral contrast agent, LumenHance (Bracco Diagnostics, Inc.). Safety was determined by comparing pre- and post-dose physical examinations, vital signs, and laboratory examinations and by documenting adverse events. Efficacy was assessed by unblinded site investigators and two blinded reviewers who compared pre- and post-dose T1- and T2-weighted MRI scans of the abdomen and/or pelvis. In 111 (57%) of the 195 cases evaluated for efficacy by site investigators (unblinded readers), MRI after LumenHance provided additional diagnostic information. Increased information was found by two blinded readers in 52% and 51% of patients, respectively. In 44/195 cases (23%) unblinded readers felt the additional information would have changed patient diagnosis and in 50 patients (26%), it would have changed management and/or therapy. Potential changes in patient diagnosis or management/therapy were seen by the two blinded readers in 8-20% of patients. No clinically significant post-dose laboratory changes were seen. Forty-eight patients (24%) receiving LumenHance and four patients (22%) receiving placebo experienced one or more adverse events. Gastrointestinal tract side effects were most common, seen in 29 (15%) of LumenHance patients and in 3 (17%) of the placebo patients. LumenHance is a safe and efficacious oral gastrointestinal contrast agent for MRI of the abdomen and pelvis.

Principles of contrast enhancement in the evaluation of brain diseases: an overview.

Intravenous contrast media are widely used in MR imaging of the brain. Clinical utility is high in both neoplastic and non-neoplastic disease. The agents approved to date are all gadolinium chelates, with extracellular distribution and renal excretion. The agents differ in regard to the maximum dose that can be administered and the theoretical safety margin. When administered at the same dose, the efficacy of the different available agents is comparable. Described in the following review article are the diagnostic use of contrast media and the patterns of enhancement encountered in neoplastic disease, infection, vascular disorders, and diseases of white matter. Only in congenital brain disease, when acute abnormalities are not suspected clinically and neoplastic disease is not a question, is contrast enhancement not indicated. The gadolinium chelates play a major role in the evaluation of patients by MR with known or suspected brain disease. These agents improve both the sensitivity and specificity of the examination. In many cases, lesions cannot be identified before contrast administration. Lesion delineation, assessment of lesion activity, and differential diagnosis are all improved, in general, with the addition of postcontrast scans. The scope of applications continues to expand as the modality and clinical experience matures.

Hepatic MR imaging with ferumoxides: a multicenter clinical trial of the safety and efficacy in the detection of focal hepatic lesions.

PURPOSE: To assess the safety and diagnostic efficacy of intravenous ferumoxides, a superparamagnetic iron oxide, for depiction of focal hepatic lesions on magnetic resonance (MR) images. MATERIALS AND METHODS: This open-label study included 208 patients with known or suspected focal hepatic lesions. MR images were obtained before and 45 minutes to 4 hours after intravenous infusion of ferumoxides (10 mumol/kg). The effect of ferumoxides on signal intensity of the liver was assessed with quantitative analysis. Safety was evaluated with patient monitoring and laboratory measurements. RESULTS: Mean lesion-to-liver contrast-to-noise ratio on T2-weighted images was 9.1 on unenhanced images and 12.7 on enhanced images. Signal intensity of normal liver on enhanced images decreased to 37% of that on unenhanced images. In blinded image evaluations, additional lesions were identified on 27% of enhanced images. No serious adverse events occurred. CONCLUSION: Ferumoxides is a safe and efficacious contrast agent for the detection of focal liver lesions on T2-weighted images.

The use of MR contrast in neoplastic disease of the brain.

Magnetic resonance imaging (MRI) is the modality of choice in the evaluation of patients with actual or suspected intracranial neoplasms. MRI has many advantages over alternative modalities. It provides increased sensitivity, permits multiplanar image display, is noninvasive, and has no associated ionizing radiation. MR contrast adds significantly to the evaluation of patients with suspected intracranial neoplasms. It further increases sensitivity to lesion detection, it more clearly defines tumor extent, and it facilitates the differentiation of tumor from normal adjacent structures. In virtually every instance, MR contrast enhances lesion conspicuity. In some cases, these neoplasms would be seen only with difficulty or not at all without the benefit of contrast enhancement. Thus, in the appropriate patient population, MR contrast enables more time-efficient and cost-effective diagnoses.

Subhypothalamic high-intensity signals identified by magnetic resonance imaging in children with idiopathic anterior hypopituitarism. Evidence suggestive of an 'ectopic' posterior pituitary gland.

Magnetic resonance imaging in two children with idiopathic hypopituitarism demonstrated a signal of high intensity near the optic tract that was consistent with the signal produced by posterior pituitary tissue. Patient 1 was a 15-year-old girl with panhypopituitarism but intact posterior pituitary function. Computed tomography disclosed widening of the superior aspect of the pituitary stalk and a partially empty sella. Magnetic resonance imaging disclosed a 3-mm high-intensity signal abutting the optic tract in the midline just above the sella. The pituitary stalk was not clearly defined, the pituitary gland was small, and the sella was filled with cerebrospinal fluid. Patient 2 was a 12-year-old boy with isolated deficiency of growth hormone secretion. Findings from magnetic resonance imaging and computed tomography were similar to those in patient 1. These data suggest that the high-intensity magnetic resonance imaging findings represent a displaced or "ectopic" posterior pituitary gland, and that the hypopituitary state is due to an insult to the pituitary stalk.

Association of heterotopic gray matter with seizures: MR imaging. Work in progress.

Heterotopic gray matter, which previously had been associated with severe congenital malformations of the brain and developmental delay, was found without these associated conditions. The authors found ten cases of heterotopic gray matter on magnetic resonance (MR) images. The lesions had a signal intensity that was isointense compared with that of gray matter on T1, spin-density, and T2-weighted images. Nine of the ten cases were associated with a seizure disorder. The tenth case, discovered during a workup for metastatic lung disease, was confirmed with pathologic studies. Heterotopic gray matter is the presence of cortical neurons in an abnormal location, which may be periventricular (nodular) or within the white matter (laminar). A knowledge of heterotopic gray matter and its association with seizures may prevent the misinterpretation of findings on MR images.

Detection of abdominal abscesses with gallium-67 citrate: correlative studies with computed tomography.

Undiagnosed abdominal abscess is a medical problem of substantial clinical importance. The high morbidity and mortality associated with this entity demand prompt, accurate diagnosis. The combined use of gallium scintigraphy and computed tomography provides the imaging tools necessary to accomplish this goal. If the suspected pathology cannot be localized, gallium scintigraphy is the initial diagnostic imaging procedure utilized. When antecedent events or clinical symptoms suggest a specific site for the suspected inflammatory collection, computed tomography (CT) is used to evaluate the area. The strengths and weaknesses of gallium scanning and computed tomography are explored in depth, and particular emphasis is given to proper technique and the avoidance of pitfalls. A logical approach to the use of these modalities in tandem is presented.

Bone scintigraphy in trauma of the hand and wrist.

Bone scintigraphy utilizing Tc-99m phosphate compounds was valuable in the diagnosis of injuries of the hand and wrist in three patients in whom conventional roentgenograms and other investigations over several months were inconclusive. With appropriate patient selection, either positive or negative scans may be helpful in assessing trauma to the hand or wrist. Full clinical evaluation is necessary for accurate interpretation of hand and wrist bone scintigraphy in order that potential causes of false positive or false negative studies may be recognized.

Right atrial myxoma presenting as nonresolving pulmonary emboli: case report.

A case of right atrial myxoma causing extensive pulmonary embolization is described. Five years elapsed between the initial consultation and the correct diagnosis. The patient has been free of symptoms for 3 years following surgical removal of the tumor. The clinical manifestations of right atrial myxoma, the differential diagnosis, and the atypical lung-scan features are discussed.

Radionuclide angiography.

Radionuclide angiography is an established, widely used diagnostic tool. It is safe, easy to perform, and the low patient radiation dose makes frequent follow-up studies feasible. High-quality scintiscans have contributed to the widespread clinical acceptance of the procedure. The areas of application include virtually every organ of the body. In the brain, abnormalities in cerebral perfusion may be detected with this technique. Hepatic and renal tumors can be differentiated from cysts with radionuclide angiography. Its application to cardiology is achieving rapid growth and acceptance in both congenital and acquired heart disease.

Encasement of the spleen: case report.

In a patient with extensive reticulum cell sarcoma involving the abdomen and thorax, encasement of the spleen was demonstrated by scintillation imaging. The features of this observation, not previously reported, and its diagnostic significance are discussed.