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C Grandin

Publications and source records attributed to C Grandin.

33 records · Page 2Linked to original sources
PubMed1995

Comparison of gadolinium-DTPA and polylysine-gadolinium-DTPA--enhanced magnetic resonance imaging of hepatocarcinoma in the rat.

RATIONALE AND OBJECTIVES: To compare the magnetic resonance (MR) imaging characteristics of gadolinium-DTPA (Gd-DTPA), a low-molecular-weight contrast agent, and polylysine-Gd-DTPA, a macromolecular contrast agent, in two types of hepatocarcinomas (HCC) in the rat. METHODS: T1-weighted spin-echo images were obtained in 13 rats with chemically induced HCC and 26 rats with Novikoff HCC before and 3 minutes to 60 hours after administration of either Gd-DTPA or polylysine-Gd-DTPA. RESULTS: Three minutes after polylysine-Gd-DTPA administration, the tumor-to-liver contrast of the two types of HCC increased significantly (positive contrast for chemically induced HCC and negative contrast for Novikoff HCC). At 30 minutes and 60 hours, the tumor-to-liver contrast remained above baseline values in chemically induced HCC and returned progressively to baseline values in Novikoff HCC. No significant increase in tumor-to-liver contrast was observed after Gd-DTPA administration. CONCLUSIONS: These results suggest that polylysine-Gd-DTPA provides a higher and more prolonged increase in tumor-to-liver contrast than Gd-DTPA.

Angiography↗
PubMed1995

Delineation of myocardial viability with PET.

UNLABELLED: Relative flow and metabolic imaging (the "mismatch pattern") with PET have been proposed to identify the presence of viable myocardium in patients with ischemic left ventricular dysfunction. Yet, optimal criteria to identify dysfunctional but viable myocardium and predict significant functional improvement have not been fully defined. METHODS: Dynamic PET imaging with 13N-ammonia and 18F-deoxyglucose to assess absolute myocardial perfusion and glucose uptake was performed in 25 patients (20 men, 5 women; mean age 57 +/- 12 yr, range 30-72 yr) scheduled for coronary revascularization because of coronary artery disease, anterior wall dysfunction and mildly depressed left ventricular ejection fraction (49% +/- 11%). Global and regional left ventricular function was evaluated by contrast left ventriculography at baseline and after revascularization. RESULTS: As judged from the changes in end-systolic volume and resting anterior wall motion before and after revascularization, 17 patients with improved wall motion score and decreased end-systolic volume were considered to have viable myocardium, whereas 8 patients with either no change in regional wall motion or increased end-systolic volume were considered to have nonviable myocardium. Before revascularization, viable myocardium showed higher absolute myocardial blood flow (77 +/- 20 versus 51 +/- 9 ml (min.100 g)-1, p = 0.004) and absolute regional myocardial glucose uptake (36 +/- 14 versus 24 +/- 11 mumole (min.100 g)-1, p = 0.04) than nonviable myocardium. CONCLUSION: This study identified absolute myocardial blood flow and normalized glucose extraction as the most powerful predictors of the return of contractile function after coronary revascularization in patients with ischemic anterior wall dysfunction.

Adult↗
PubMed1993

Evaluation of a nitroxyl fatty acid as liver contrast agent for magnetic resonance imaging.

In this study, we report the synthesis and the evaluation as MRI contrast agent of a new compound (nitroxyl fatty acid, NFA), where a pyrrolidinoxyl radical (3-carboxy-proxyl, PCA) is linked to a fatty acid moiety. Fatty acids were selected as vector because they present a high affinity for the liver, their efficient cellular uptake being the result of a specific interaction with a transmembrane transporter (liver plasma membrane-fatty acid binding protein). The uptake of 3H-oleic acid is inhibited after the injection of 1 mmol/kg of NFA, suggesting that NFA recognizes the same transmembrane transporter as the natural fatty acids. The higher relaxivity R1 of NFA in albumin solutions, compared with PCA, was explained by the immobilization of the nitroxyl radical in the protein. MR imaging was performed using T1-weighted images on mice in order to compare the contrast effect obtained after the injection of 1 mmol/kg of radical. The % signal enhancement in the liver 5 min after intravenous injection was 49 +/- 4 and 14 +/- 5 for NFA and PCA, respectively. NFA allowed a better delimitation of some necrotic tumors (Novikoff hepatocarcinoma) due to its preferential uptake by the nontumorous tissue.

Animals↗
PubMed1993

Hodgkin's and non-Hodgkin's hepatic lymphoma: sonographic findings.

The sonographic studies of 72 patients with pathologically proven Hodgkin's or non-Hodgkin's hepatic lymphoma were retrospectively reviewed. Sixty-eight patients (94%) had secondary hepatic lymphoma (nine of them had AIDS-related lymphoma) and four patients (6%) had primary lymphoma of the liver. Forty-six of 72 patients (64%) had diffuse hepatic involvement, and 26 of 72 patients (36%) had focal liver lesions as demonstrated by sonography. Four patterns of disease were identified: (a) hepatomegaly was depicted by sonography in 26 of the 59 patients with secondary hepatic lymphoma not related to AIDS, in two of the nine patients with AIDS-related secondary hepatic lymphoma, and in one of the four patients with primary hepatic lymphoma; (b) multiple rounded well-delineated hypoechoic liver lesions were found in 22 of the 68 patients with secondary hepatic lymphoma; (c) a large heterogeneous echoic mass, which was an evocating clue to the diagnosis of primary lymphoma of the liver, was found in the four patients with primary lymphoma of the liver; and (d) an absence of sonographic abnormalities was found in 20 of the 59 patients with secondary lymphoma not related to AIDS. Liver involvement with lymphoma should be considered in any patient who develops multiple homogeneous hypoechoic liver masses, even in the absence of known underlying lymphomatous disease.

Adult↗
PubMed1993

Primary lymphoma of the liver: MR findings.

Primary lymphoma of the liver is a rare disease. The MR appearances of three cases of pathologically confirmed primary non-Hodgkin's lymphoma of the liver are presented. All three lymphomatous lesions appeared as unique well demarcated focal liver lesions on MR images. On T1-weighted images, two lesions were hypointense and one slightly hyperintense to the liver. On T2-weighted images, the three lesions were slightly heterogeneous and hyperintense. Lobulation, which was better seen on T2-weighted images, was noticed in one lesion. One lesion was studied after gadopentetate dimeglumine injection and showed marked and heterogeneous enhancement.

Contrast Media↗
PubMed1992

Regenerative nodules in hepatic cirrhosis. Value of gradient-echo MR imaging with a surface coil.

To evaluate the accuracy of surface coil gradient-echo (GRE) imaging in the detection of regenerative nodules of hepatic cirrhosis, 53 patients with diffuse liver disease, among whom 31 had cirrhosis, were prospectively investigated. Three GRE sequences acquired with a surface coil were used in the study: a T2*-weighted, a T1-weighted, and a gadopentetate-enhanced sequence. ROC analysis showed that two surface coil GRE sequences were superior to conventional T2-weighted spin-echo imaging acquired with a body coil for the detection of regenerative nodules. The detection of regenerative nodules was also more accurate for the diagnosis of cirrhosis than the measurement of the caudate-to-right lobe ratio. These results suggest that there could be a potential for surface coil GRE imaging in the assessment of the characteristic macroscopic alterations of cirrhosis.

Adult↗
PubMedDate not supplied

Gd-EOB-DTPA enhancement pattern of hepatocellular carcinomas in rats: comparison with Tc-99m-IDA uptake.

The enhancement pattern of chemically induced hepatocellular carcinomas (HCCs) after intravenous administration of the hepatobiliary magnetic resonance (MR) contrast agent gadolinium-EOB-DTPA (ethoxybenzyl-diethylenetriaminepentaacetic acid) was compared with the uptake pattern of technetium-99m-labeled iminodiacetic acid (IDA), a hepatobiliary radioactive tracer. The hepatocyte uptake of both the contrast agent and the scintigraphic agent has been shown to be driven by the organic anion transporter. The tumors enhanced less than the liver after Gd-EOB-DTPA administration, whereas the Tc-99m-IDA uptake of differentiated HCCs exceeded that of the liver at 30 minutes and 3 hours after administration. The enhancement pattern of a differentiated HCC with Gd-EOB-DTPA does not mirror that seen with Tc-99m-IDA.

Animals↗
PubMedDate not supplied

Magnetic resonance imaging of lower abdominal and pelvic lesions: assessment of oral magnetic particles as an intestinal contrast agent.

To determine the value of oral magnetic particles (OMP) as a superparamagnetic MR contrast agent for the gastrointestinal tract in lower abdominal and pelvic lesions, 30 patients underwent spin-echo imaging before and after ingestion of OMP at a dose of approximately 80 mg of iron in 800 ml water. The preparation was divided into four portions and taken by the patient over a 2-h period. Two readers independently reviewed the MR images. The contrast material was well tolerated and the distribution of the contrast material was good to excellent in the proximal and pelvic small bowel, but was not sufficient in the colon with the dose and timing used in the study. Postcontrast images showed a significantly better delineation of the lesions, the small bowel, and the paraaortic region, but no significant improvement in the delineation of the colon, the iliac vessels area, the bladder or genital tract. Compared with precontrast images, confidence in defining or excluding disease on postcontrast images was better, equal or worse in 40, 60 and 0% of cases, respectively (P less than 0.001) with a substantial agreement between readers (kappa = 0.71). OMP produced susceptibility artefacts of significant intensity in only one case. These results indicate that OMP may be useful in the delineation of lower abdominal and pelvic lesions at MR imaging. Marking of the colon by a contrast agent might improve the results.

Abdominal Neoplasms↗
PubMedDate not supplied

Dynamic CT in pancreatic lymphoma.

We retrospectively reviewed the dynamic CT examinations of eight patients with pancreatic lymphoma. Four tumors were rounded masses with well-defined contours, four were more infiltrating lesions. The median cross-sectional diameter of the tumors was 6 cm (range 2.5-12 cm). At dynamic CT, the tumors were hypodense (n = 8) and somewhat heterogeneous (n = 6). Additional features were enlarged lymph nodes, 1-3 cm in diameter (n = 5), dilatation of the biliary tract and pancreatic duct (n = 5), abnormalities in the fat around the celiac trunk and/or the superior mesenteric artery (n = 4), and venous stenosis or occlusion (n = 7). The CT findings of pancreatic lymphoma are more various than has been previously reported. Findings such as small tumor size, well-defined contours, tumor heterogeneity, pancreatic duct dilatation, and venous invasion may be seen. Pancreatic lymphoma cannot be reliably distinguished from pancreatic carcinoma by CT findings alone.

Adipose Tissue↗
PubMedDate not supplied

MRI of complicated anal fistulae: comparison with digital examination.

OBJECTIVES: The assessment of complicated anal fistulae is based on digital examination. Our objective was to study the potential role of MRI in this setting by comparing preoperative digital examination with MRI. MATERIALS AND METHODS: Digital examination and MRI were prospectively and blindly interpreted in 13 patients with complicated anal fistulae. Surgical findings were used as standard. RESULTS: Complete agreement between the results of digital examination and the surgical findings was observed in 8 patients and between the results of MRI and the surgical findings in 12 patients. Digital examination misclassified two low transsphincteric fistulae as high transsphincteric and missed high secondary extensions or abscesses in three other patients. Magnetic resonance misclassified only one suprasphincteric fistula as low transsphincteric and did not overlook high secondary extensions or abscesses. CONCLUSION: These findings suggest that MRI may show abnormalities not detected by preoperative digital examination.

Adult↗
PubMedDate not supplied

MR-monitored remitting-relapsing pattern of cortical involvement in Rasmussen syndrome: comparative evaluation of serial MR and PET/SPECT features.

We report the serial MR and PET/SPECT findings in a 2 1/2-year-old boy presenting with Rasmussen syndrome and highlight the close qualitative correlations between the results of the imaging modality and the functional isotopic techniques. The latter demonstrated a wider field of extension of the disease process. Routine MRI demonstrated its ability to detect brain changes matching the more sensitive PET and SPECT data and correlated well with the clinical evolution.

Brain Diseases↗
PubMedDate not supplied

Benign hepatocellular tumors: MRI after superparamagnetic iron oxide administration.

OBJECTIVE: Our goal was to describe the features of benign hepatocellular tumors on superparamagnetic iron oxide (SPIO)-enhanced MR images and to evaluate the potential role of SPIO administration in the diagnosis of these tumors. MATERIALS AND METHODS: The T1- and T2-weighted SE images were performed before and after SPIO administration in 19 patients with focal nodular hyperplasia (FNH) or adenomas. The lesions were counted and qualitatively assessed. In 32 tumors with a diameter of > 10 mm, the contrast-to-noise ratio (CNR) and the liver and tumor enhancement were calculated. RESULTS: Thirty-seven tumors were detected on MR images: 29 before and 36 after SPIO administration (p < 0.05). The SPIO-enhanced T1-weighted images provided the highest detection rate and CNR. The central scar was most conspicuous on SPIO-enhanced T2-weighted images. Most FNHs and adenomas lost less signal than the liver, three tumors did not lose signal, and four FNHs showed a signal loss equal to or greater than that of the liver. CONCLUSION: The SPIO-enhanced T1-weighted images increased the CNR and the detection rate of benign hepatocellular tumors. On T2-weighted images, most benign hepatocellular tumors showed a signal decrease after SPIO administration. No significant difference in signal loss was observed between FNH and adenomas.

Adenoma↗