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Biomedical subjects

C B Higgins

Publications and source records attributed to C B Higgins.

At least 37 records · Page 2Linked to original sources
PubMed2000

Normal and infarcted myocardium: differentiation with cellular uptake of manganese at MR imaging in a rat model.

PURPOSE: To assess whether normal myocardium can be distinguished from infarction at magnetic resonance (MR) imaging with low doses of manganese dipyridoxyl diphosphate (Mn-DPDP). MATERIALS AND METHODS: After 1-hour coronary arterial occlusion and 2-hour reperfusion, three groups of eight rats each were injected with 25, 50, or 100 micromol of Mn-DPDP per kilogram of body weight. The longitudinal relaxation rate (R1) in normal myocardium, reperfused infarction, and blood was repeatedly measured at inversion-recovery echo-planar imaging before and for 1 hour after the administration of contrast material. Afterward, several animals from each group were examined at high-spatial-resolution inversion-recovery spin-echo (SE) MR imaging. RESULTS: Manganese accumulated in normal myocardium but was cleared from reperfused infarction and blood. One hour after the administration of Mn-DPDP, R1 in normal myocardium (1.53 sec(-1) +/- 0.03, 1.73 sec(-1) +/- 0.03, and 1.94 sec(-1) +/- 0.02, respectively, for 25, 50, and 100 micromol/kg) was significantly (P <.05) faster than that of reperfused infarction (0.99 sec(-1) +/- 0.03, 1.11 sec(-1) +/- 0.03, and 1.48 sec(-1) +/- 0.06). Normal myocardium appeared hyperintense on T1-weighted inversion-recovery SE MR images and was clearly distinguishable from reperfused infarction. CONCLUSION: Mn-DPDP-enhanced inversion-recovery echo-planar and SE MR images demonstrated retention of manganese in normal myocardium and clearance of manganese from infarction. Mn-DPDP has characteristics similar to those of widely used thallium and may be useful in the assessment of myocardial viability at MR imaging.

Analysis of Variance↗
PubMed2000

Cardiac imaging.

The emergence of noninvasive imaging techniques for the definitive diagnosis and monitoring of cardiovascular disease has greatly altered cardiac imaging in the past 25 years. The practice of cardiac imaging in 1975 was centered on conventional radiography and angiography, but, in the past 2 decades, noninvasive techniques have substantially replaced catheterization and angiography. The reliance on echocardiography for the evaluation of many cardiac diseases had a profoundly negative influence on the role of the radiologist in cardiac imaging, since the exercise of this modality has been a nearly exclusive province of the cardiologist. However, in the past decade, magnetic resonance imaging has been gradually assuming more importance in cardiovascular diagnosis; with this increase in importance, the role of the radiologist has been reactivated. In 1975, fellowship training in cardiac imaging was frequently combined with training in angiography. Now, training may be more effective by combining cardiac and pulmonary imaging in a thoracic imaging fellowship, but cross-training with an associated subspeciality will be influenced by priorities and personnel in various departments.

Cardiology↗
PubMed2000

Coronary sinus flow measurement by means of velocity-encoded cine MR imaging: validation by using flow probes in dogs.

PURPOSE: To validate coronary sinus flow measurements for quantification of global left ventricular (LV) perfusion by means of velocity-encoded cine (VEC) magnetic resonance (MR) imaging and flow probes. MATERIALS AND METHODS: Measurements of coronary sinus flow were performed in seven dogs by using VEC MR imaging at baseline, single coronary arterial stenosis, dipyridamole stress, and reactive hyperemia. These measurements were compared with flow probe measurements of coronary blood flow (CBF) in the left anterior descending coronary (LAD) and circumflex (CFX) arteries (CBF(LAD+CFX)) and coronary sinus. LV blood perfusion was calculated in milliliters per minute per gram from coronary sinus flow, and LV mass was obtained by using VEC and cine MR imaging. LV mass was validated at autopsy. RESULTS: CBF(LAD+CFX) and coronary sinus flow at VEC MR imaging showed close correlation (r = 0.98, P: <.001). The difference between CBF(LAD+CFX) and MR coronary sinus flow was 3.1 mL/min +/- 8.5 (SD). LV mass at cine MR imaging was not significantly different from that at autopsy (73.2 g +/- 12.8 vs 69. 4 g +/- 12.8). At baseline, myocardial perfusion was 0.40 mL/min/g +/- 0.09 at VEC MR imaging, and CBF(LAD+CFX) was 0.44 mL/min/g +/- 0. 08 (not significant). Reactive hyperemia resulted in 2.7- and 2. 3-fold increases in coronary sinus flow at VEC MR imaging and flow probe CBF(LAD+CFX), respectively. CONCLUSION: VEC MR imaging has the potential to measure coronary sinus flow during different physiologic conditions and can serve as a noninvasive modality to quantify global LV perfusion in patients.

Animals↗
PubMed2000

MR imaging of the thoracic aorta.

MR imaging is an effective modality for noninvasive morphologic and functional assessment of the thoracic aorta. MR imaging provides several advantages for vascular imaging, including intrinsic contrast between the blood pool and vascular structures, multiplanar imaging capability, and the absence of ionizing radiation. By combining imaging and flow-sensitive techniques, MR imaging can be used to delineate morphology and to quantify bloodflow volume and velocity. In patients who need sequential examinations over time to monitor disease severity, a noninvasive technique such as MR imaging is desirable.

Aorta, Thoracic↗
PubMed2000

MR imaging of the thyroid and parathyroid glands.

Whereas scintigraphy and ultrasonography are the primary imaging modalities used for the investigation of thyroid disorders, MR imaging is generally used for specific indications, including evaluating the extent of substernal goiters, assessing the effect on adjacent structures, imaging the local extent of thyroid carcinomas, and localizing recurrent sites of thyroid neoplasia. MR imaging also has been used for the investigation of congenital disorders of the thyroid gland and the evaluation of diffuse thyroid disease, such as Grave's disease, Hashimoto's and Riedel thyroiditis, and hemochromatosis. MR imaging of the parathyroid glands is generally used for patients with recurrent or persistent hyperparathyroidism following neck exploration. MR imaging provides useful information about morphologic abnormalities of the thyroid and parathyroid glands. MR imaging has good sensitivity and positive predictive value for the identification of non-ectopic and ectopic abnormal parathyroid glands. The detailed anatomic information provided by MR imaging is useful in planning a surgical approach and is complementary to other imaging methods used in the investigation of recurrent or persistent hyperparathyroidism.

Humans↗