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Biomedical subjects

V M Runge

Publications and source records attributed to V M Runge.

At least 73 records · Page 4Linked to original sources
PubMed1993

Assessment of cerebral perfusion by first-pass, dynamic, contrast-enhanced, steady-state free-precession MR imaging: an animal study.

OBJECTIVE: The purpose of this study was to determine whether cerebral perfusion could be assessed with a conventional 1.5-T MR imaging system by applying a steady-state free-precession (SSFP) technique during bolus IV injection of contrast material (gadoteridol). Normal and abnormal perfusion states and the effect of the dose of contrast material were studied in cats. MATERIALS AND METHODS: Nine healthy anesthetized cats were imaged after administration of 0.5 mmol/kg (n = 5), 0.25 mmol/kg (n = 2), and 0.1 mmol/kg (n = 2) of gadoteridol. Six cats with an acute infarct of the middle cerebral artery (five cats 10 min after and one cat 1 hr after vessel occlusion) were evaluated at a dose of 0.5 mmol/kg. The middle cerebral artery was ligated in each instance by use of a snare placed around the vessel during surgery, which was performed via a transorbital approach. Each animal was imaged with spin-echo T2-weighted (3000/45,90 [TR/TE]) and T1-weighted (500/10) techniques before contrast material was injected. SSFP images (12/18, 80 degrees tip angle) were acquired sequentially (each with a 1-sec acquisition time and no interimage delay) immediately before and for 45 sec after IV injection of a bolus of gadoteridol. RESULTS: The first-pass effect in both normal gray and white matter was dose dependent, with a greater magnitude of change seen at higher doses of contrast material. A 55% decrease in signal intensity of normal peripheral gray matter was observed during the first pass after bolus injection of 0.5 mmol/kg gadoteridol, compared with a 23% decrease and a 17% decrease at doses of 0.25 and 0.1 mmol/kg, respectively. High temporal (one image per second) and spatial (1.5 x 1.5 x 6.0 mm) resolution was achieved, with sufficient sensitivity that both visual and statistical differentiation of normal and abnormal gray and white matter was possible. Ten minutes after vessel occlusion, the change in signal intensity during the first pass was 45 +/- 5% and 27 +/- 9% for normal central gray and white matter, respectively, as compared with 20 +/- 2% and 11 +/- 5% for ischemic central gray and white matter, respectively. CONCLUSION: Cerebral perfusion can be assessed on conventional 1.5-T MR imaging systems by combining high-dose IV bolus injection of contrast material (in this instance, using gadoteridol) with dynamic SSFP imaging.

Animals↗
PubMed1993

Enhanced liver MR: contrast agents and imaging strategy.

Contrast enhancement in liver MR can be achieved by a variety of fundamentally different strategies. The published clinical literature regarding Gd DTPA (gadopentetate dimeglumine), Gd HP-DO3A (gadoteridol), Gd BOPTA (gadobenate dimeglumine), Mn DPDP, and AMI-25 is reviewed, followed by a brief discussion of two new iron particulate agents currently in preclinical trials. Different imaging techniques also must be used for visualization of contrast enhancement depending on the specific type of agent utilized. With both gadolinium and manganese chelates, T1 weighted sequences are used to visualize the effect of the contrast agent. There is positive enhancement (an increase in signal intensity) of normal liver parenchyma post-contrast due to enhanced T1 relaxation. With iron particulate agents, T2 weighted sequences are used. In this instance, there is negative enhancement (a decrease in signal intensity) of normal liver post-contrast due to enhanced T2 relaxation. Clinical use at present is limited to the extracellular gadolinium chelates, with bolus injection and dynamic imaging improving efficacy. Current research also supports the use of a high dose (0.3 mmol/kg) for improved lesion detectability, a finding now clinically relevant due to the recent approval of Gd HP-DO3A at both standard and high doses.

Contrast Media↗
PubMed1992

Efficacy of gadoteridol for magnetic resonance imaging of the brain and spine.

RATIONALE AND OBJECTIVES: The efficacy of gadoteridol for contrast enhancement of central nervous system pathology was assessed in a multicenter clinical trial involving 411 patients suspected of having intracranial or spinal pathology. METHODS: Magnetic resonance imaging was performed before and after intravenous administration of 0.10 mmol/kg gadoteridol. Two groups of images were interpreted by one of two neuroradiologists blinded to patient history. The results were analyzed separately. RESULTS: Patients with radiologic evidence of disease demonstrated enhancement of intracranial pathologic lesions in 44 of 63 (70%) and in 91 of 111 (82%) cases, respectively, whereas enhancement of spinal lesions was observed in 36 of 58 (62%) and in 65 of 78 (83%) cases, respectively. Subjectively, postcontrast scans provided more information than precontrast images in 37 of 63 (59%) and 84 of 111 (76%) intracranial cases, respectively, and in 25 of 58 (43%) and 55 of 78 (71%) spinal cases, respectively. Additional information included the subjective sense that there was improved visualization of pathology and definition of lesion borders. CONCLUSIONS: Subjective assessment of magnetic resonance scans suggest gadoteridol is an effective intravenous contrast agent for magnetic resonance imaging.

Adolescent↗
PubMed1992

Magnetic resonance imaging contrast agents.

Intravenous contrast enhancement has assumed a prominent position in clinical MR imaging, particularly for studies of the head and spine. New chelates such as gadoteridol are likely to be approved in the near future; gadopentetate dimeglumine is the only agent approved for clinical use in the United States. Clinical applications have rapidly expanded for the gadolinium chelates with extracellular distribution. Within the next decade, approval is anticipated for a variety of additional agents that may help assess tissue function.

Abdomen↗
PubMed1991

High-dose applications of gadolinium chelates in magnetic resonance imaging.

Administration of gadolinium chelates at doses greater than 0.1 mmol/kg IV can potentially improve both lesion detection and the assessment of tissue perfusion. Preliminary results are presented in clinical patients and two animal models. In human intracranial metastatic disease, administration of 0.3 (cumulative dose) mmol/kg gadoteridol (Gd HP-DO3A) has permitted detection of additional lesions not visualized at 0.1 mmol/kg. In a rabbit model of focal liver disease, 0.5 mmol/kg IV provided superior enhancement of both normal parenchyma and lesion rim compared to doses of 0.25 and 0.1. Dynamic imaging (T1-weighted turbo-FLASH) immediately following bolus injection of 0.5 mmol/kg permitted direct visualization (on unsubtracted images) of an acute perfusion defect in the cat brain not visible on conventional T1- and T2-weighted scans.

Animals↗
PubMed1991

Gd HP-DO3A--experimental evaluation in brain and renal MR.

GD HP-DO3A, a neutral (nonionic) IV MR contrast agent presently in clinical trials, was evaluated with respect to imaging characteristics in rats. Following administration of 0.25 mmol/kg I.V., 58 +/- 19%, i.e. (n = 6) enhancement was noted in a brain gliosarcoma model. Meningeal spread of neoplasia could be identified due to its enhancement (69 +/- 26%) in nine animals. The time course of renal enhancement was quantitated at two dosages, 0.05 (n = 4) and 0.25 mmol/kg (n = 8). At the higher dose, enhancement of both cortex and medulla plateaued between 9 and 23 min postinjection. At the lower dose, enhancement of renal medulla was maximum at 2 min postinjection. These enhancement characteristics (both brain and kidney), at equivalent contrast dosages, are comparable to that previously published for Gd-DTPA. However, Gd HP-DO3A has the potential to be utilized clinically at higher doses than Gd-DTPA, with no reported adverse effects in initial trials employing up to 0.3 mmol/kg.

Animals↗
PubMed1991

Clinical safety and efficacy of gadoteridol: a study in 411 patients with suspected intracranial and spinal disease.

In this phase III study, 411 adult patients with suspected intracranial or spinal disease underwent magnetic resonance (MR) imaging before and after intravenous injection of 0.1 mmol/kg gadoteridol (gadolinium 1,4,7-tris [carboxymethyl]-10-[2'-hydroxypropyl]-1,4,7,10-tetraazacyclododecane+ ++). MR images were evaluated by a single unblinded reader at each of 27 sites; the diagnosis was confirmed with one of nine imaging or surgical procedures within 8 weeks before or after MR imaging. After injection, no clinically significant changes were noted in laboratory values, physical examination, or vital signs. Adverse clinical events possibly or probably associated with injection of gadoteridol were seen in 18 of 411 patients (4.4%); the most common were dysgeusia and mild nausea, and all abated without residual effects. MR images enhanced with gadoteridol in patients with confirmed disease provided more diagnostic information than unenhanced images in 128 of 175 brain examinations (73.1%) and 93 of 137 spinal examinations (67.9%). A change in diagnosis because of additional information from contrast-enhanced images was considered likely in 63 of 214 cranial and 54 of 161 spinal studies.

Adult↗
PubMed1991

Clinical applications of magnetic resonance contrast media in the head.

The clinical utility of paramagnetic metal ion chelates for contrast enhancement in MRI of the brain is well established. Contrast administration provides both improved sensitivity and specificity with respect to diagnosis in neoplasia, infection, demyelinating disease, infarction, and arteriovenous abnormalities. On the basis of results from prospective studies, use of enhanced scans, in addition to baseline precontrast T1- and T2-weighted scans, is advocated in all patient studies in which there is a high index of suspicion with respect to intracranial pathology.

Brain Diseases↗
PubMed1991

Future directions in magnetic resonance contrast media.

In June 1988 Gd DTPA became the first MR contrast agent to be approved for clinical use in adult patients in the United States. Initial approval was given for its use in imaging of the head. One year later approval was extended to include spine studies. This was soon followed by approval for use in children aged 2 years and older. Research is continuing to expand the applications of Gd DTPA in MR imaging of the musculoskeletal system, abdomen, and in MR angiography. Research is ongoing in the development of new agents, attempting to reduce toxicity, permit increased doses, or target specific organs. Gd DOTA has been in clinical use in Europe for approximately 1 year. Two neutral (nonionic) agents, Gd HP-DO3A and Gd DTPA-BMA, have just completed phase III clinical trials. Mn DPDP and AMI-25 are two targeted compounds that have entered clinical trials. Formulations intended for opacification of the gastrointestinal tract, with both Gd DTPA and magnetic particles, have been evaluated in Europe and in the United States.

Contrast Media↗
PubMed1990

3-D imaging of the CNS.

3-D gradient echo techniques, and in particular FLASH, represent a significant advance in MR imaging strategy allowing thin section, high resolution imaging through a large region of interest. Anatomical areas of application include the brain, spine, and extremities, although the majority of work to date has been performed in the brain. Superior T1 contrast and thus sensitivity to the presence of GdDTPA is achieved with 3-D FLASH when compared to 2-D spin echo technique. There is marked arterial and venous enhancement following Gd DTPA administration on 3-D FLASH, a less common finding with 2-D spin echo. Enhancement of the falx and tentorium is also more prominent. From a single data acquisition, requiring less than 11 min of scan time, high resolution reformatted sagittal, coronal, and axial images can obtained in addition to sections in any arbitrary plane. Tissue segmentation techniques can be applied and lesions displayed in three dimensions. These results may lead to the replacement of 2-D spin echo with 3-D FLASH for high resolution T1-weighted MR imaging of the CNS, particularly in the study of mass lesions and structural anomalies. The application of similar T2-weighted gradient echo techniques may follow, however the signal-to-noise ratio which can be achieved remains a potential limitation.

Adult↗
PubMed1990

The prospective evaluation of Gd-DTPA in 225 consecutive cranial cases: adverse reactions and diagnostic value.

This prospective study evaluates two facets of gadopentetate dimeglumine (Gd-DTPA) enhanced MR imaging in 225 consecutive cranial cases in patients greater than 18 years of age: (i) patient and physician perception of adverse reactions, (ii) diagnostic value of the Gd-DTPA enhanced exam. The 225 cases included 173 head cases, 27 IAC cases, and 25 sella cases. Forty-six percent of the cases were abnormal excluding cases of mild atrophy and ischemic white matter disease judged to be related to aging and not pertinent to the patient's presenting complaint. Concerning adverse reactions, 83% of patients had no complaints. Five percent of the patients had reactions that were judged by the physician to be related to Gd-DTPA. All reactions were minor and required no therapy. In a subset of exams (115) that were blindly and independently interpreted by two board-certified, fellowship-trained radiologists, the Gd-DTPA-enhanced exam resulted in a change in diagnosis in 5%-8% of cases. Additionally, a major benefit of Gd-DTPA administration was the increased diagnostic confidence afforded by the addition of a contrast enhanced exam due to improved lesion characterization and exclusion of additional significant intracranial pathology. In 52%-69% of the abnormal cases, Gd-DTPA provided additional diagnostic information and in 26%-39% the absence of enhancement aided in interpretation. The Gd-DTPA-enhanced exam aids in the diagnosis and characterization of neoplastic disease, acoustic neuroma, subacute infarction, inflammatory disease (meningeal and parenchymal), and certain vascular abnormalities.

Brain Diseases↗
PubMed1990

Gd-HP-DO3A in clinical MR imaging of the brain.

As part of a phase II clinical trial, 14 patients with presumed intracranial neoplastic disease underwent magnetic resonance (MR) imaging before and after intravenous injection of gadolinium 1,4,7-tris(carboxymethyl)-10-(2'-hydroxypropyl)-1,4,7,10-tetraazacycl ododecane (HP-DO3A). This neutral (nonionic) gadolinium chelate has lower osmolality, when formulated at equimolar concentrations, and superior in vitro stability compared with gadopentetate dimeglumine. The safety profile of Gd-HP-DO3A permitted administration of doses up to 0.3 mmol/kg, three times the dose of gadopentetate dimeglumine approved by the U.S. Food and Drug Administration. In this limited clinical trial, Gd-HP-DO3A proved to be a safe and efficacious agent in MR imaging of the head. The only change documented in patient monitoring was that of slight skin redness at the injection site immediately after administration in two patients. No statistically significant changes due to administration of the agent were noted in laboratory evaluations. These results differ from those obtained with gadopentetate, which induces a transient rise in serum iron and bilirubin levels in up to 26% of patients. Administration of higher doses of Gd-HP-DO3A, either 0.2 or 0.3 mmol/kg, appeared to provide improved enhancement. No decrease in efficacy at these high doses was noted.

Adult↗
PubMed1989

Experimental trials with Gd(DO3A)--a nonionic magnetic resonance contrast agent.

Gd(DO3A), a member of a new family of nonionic MRI contrast agents, was evaluated in vivo in a rat model. In 10 animals, enhancement of an intracerebral glioma was studied following Gd(DO3A) injection. Correlation with tissue pathology was obtained in all cases. Comparative studies of renal enhancement were performed in 15 animals, utilizing disodium Gd(DTPA)2-, sodium-Gd(DOTA)-, and Gd(DO3A). With the glioma model, Gd(DO3A) administration provided enhancement of tissue with an altered blood brain barrier, thus permitting identification of the bulk of the neoplastic lesion. Comparative studies revealed that enhancement of normal renal medulla was equal or superior with Gd(DO3A).

Animals↗
PubMed1989

Anatomy of the proximal femur as seen with three-dimensional magnetic resonance imaging.

Magnetic resonance imaging (MRI) is being applied successfully to the study of the musculoskeletal system with notable recent advances, including the use of three-dimensional imaging techniques. The authors introduce three-dimensional MRI as a technique for examining proximal femoral anatomy and suggest its use as an improvement on current methods for prosthetic hip design. The proximal femurs of 14 cadavers were scanned using a three-dimensional FISP technique and the images were subsequently manipulated on a three-dimensional MRI image-processing workstation to produce rotated surface reconstructions and multiplanar reformatted images. The surface rotations showed that the marrow cavity contours closely follow the contours of the external cortex. Axially reformatted images allowed relative area measurements of the marrow cavity, quantifying the variability between subjects.

Aged↗
PubMed1989

Gd DTPA: a review of clinical indications in central nervous system magnetic resonance imaging.

Since its approval for clinical use in mid 1988, Gd DTPA has found widespread application as a contrast agent in MRI. This paramagnetic metal ion chelate is used primarily for enhancement of head and spine lesions. Indications for contrast agent use in MRI are summarized drawing upon experience in more than 600 patients and a review of the literature. Enhancement improves both lesion detection and categorization. In head examinations, we recommend use of Gd DTPA for studies of the internal auditory canal, metastatic disease, infarction, infection, meningeal disease, and primary neoplastic disease. In spine examinations, contrast enhancement is employed both for detection of neoplastic disease and in the postoperative back for the differentiation of scar from recurrent disk herniation. Gd DOTA and Gd DO3A-R are new agents within this same class of contrast media.

Brain Neoplasms↗