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PubMed1999

Comparison of digital subtraction angiography with gadolinium-enhanced magnetic resonance angiography in the diagnosis of renal artery stenosis.

Renal artery stenosis (RAS) is a treatable cause of hypertension and renal failure for which no ideal screening technique is currently available. We evaluated the use of dynamic gadolinium-enhanced magnetic resonance angiography (MRA) for the diagnosis of RAS. Sixty-two patients with secondary hypertension were enrolled in the study. All patients had conventional renal angiography and gadolinium enhanced MRA. The sequence used was a 3D FMP SPGR sequence with the following parameters (TR: 26 ms, TE: 6.9 ms, flip angle 40 degrees, field of view 36 x 36 cm, matrix 246 x 256, 1 excitation). Gadolinium 0.3 mmol/kg was administered and 60 1. 5-mm-thick partitions were obtained over a duration of 3.5 min. The MRA images were then compared with conventional digital subtraction angiography (DSA) images. Conventional DSA demonstrated 138 renal arteries, whereas gadolinium-enhanced MRA demonstrated 129 (93 %). Twenty-one renal artery stenoses and four occluded arteries were seen at conventional DSA. Gadolinium-enhanced MRA had a sensitivity of 88 %, specificity of 98 %, accuracy of 96 %, positive predictive value of 92 % and negative predictive value of 97 % when compared with conventional DSA. Gadolinium-enhanced MRA is an accurate technique for identifying patients with RAS. It is less sensitive in picking up accessory renal arteries.

Angiography, Digital Subtraction↗
PubMed2004

Gadolinium-DTPA-dextran: a macromolecular MR blood pool contrast agent.

RATIONALE AND OBJECTIVES: Magnetic resonance (MR) imaging blood pool agents offer numerous advantages for vascular and tumor imaging. The purpose of this study was to test gadolinium-diethylenetriaminepentaacetate-dextran ([Gd]DTPA-dextran) as a new water soluble macromolecular blood pool agent for MR imaging. MATERIALS AND METHODS: [Gd]DTPA-dextran (187 gadolinium atoms per dextran, molecular weight 165 kD, diameter 17.6 nm) was synthesized. Fifteen anesthetized New Zealand White rabbits with thigh VX2 tumors were scanned in a knee coil at 1.5T. Coronal 3D MR angiographic sequences were obtained before and at several time points up to 72 hours after the intravenous bolus injection of [Gd]DTPA-dextran providing gadolinium at either 0.05 (n = 4) or 0.1 mmol/kg (n = 8) or [Gd]DTPA-bismethylamide (BMA) providing gadolinium at 0.1 mmol/kg (n = 3). Time enhancement curves for aorta, cava, and tumor rim were compared by univariate General Linear Model. RESULTS: Contrast enhancement of cava and aorta relative to a water phantom were significantly greater at all time points after either dose of [Gd]DTPA-dextran than after [Gd]DTPA-BMA (P < 0.01). Tumor rim enhancement was less intense for either dose of [Gd]DTPA-dextran at peak than for [Gd]DTPA-BMA (P < 0.05). Tumor rim enhancement with both doses of [Gd]DTPA-dextran became equivalent to that of [Gd]DTPA-BMA at one hour and was greater at 24 hours (P < 0.05). CONCLUSION: [Gd]DTPA-dextran is a new macromolecular MR contrast agent that can be synthesized to carry a high density of gadolinium atoms without intra-molecular cross-linking. It provides significantly greater vascular residence time than a conventional gadolinium chelate and shows promise for MR blood pool imaging.

Animals↗
PubMed2006

Investigations into the physicochemical properties of dextran small particulate gadolinium oxide nanoparticles.

RATIONALE AND OBJECTIVES: Relatively few studies involving the physicochemical properties of crystalline, nanometer-sized particulate gadolinium complexes have been reported. This is in part because of the challenges associated with making nanoparticulate gadolinium suspensions that are stable in aqueous solution. Small particulate gadolinium oxide (SPGO) and SPGO embedded in albumin microspheres (gadolinium oxide albumin microspheres, GOAM), have been used experimentally as prototype contrast agents for multimodality imaging. MATERIALS AND METHODS: In the present study, an initial attempt was made to better solubilize SPGO, prevent particle aggregation, and investigate the physicochemical properties of dextran SPGO relevant to its use as a high-field magnetic resonance contrast agent in aqueous solution. RESULTS: Dextran SPGO demonstrates regular crystalline lattices and has a gadolinium oxide electron diffraction pattern consistent with that of published X-ray powder diffraction (XPD) patterns. The subtraction XPD pattern of dextran SPGO shows diffraction angles and intensities similar, but not identical, to that of published Gd2O3 diffraction patterns. High r2/r1 ratios and magnetic susceptibility studies indicate dextran SPGO can be classified as a superparamagnetic compound. Enhanced relaxivity is observed at high magnetic field strength; largely because of solubilization of SPGO via the surface adherent carbohydrate. Perhaps also contributing to the observed relaxivity enhancement is the ideal lattice structure of the central gadolinium oxide crystal and the effects of sonochemical preparation on nanoparticle physicochemical properties. CONCLUSIONS: It is anticipated that these studies will help provide a basis for the development of novel nanoparticulate contrast agent platforms capable of improving T1 and T2/T2* contrast for high-field magnetic resonance imaging and molecular imaging.

Contrast Media↗
PubMed2004

Effects of gadolinium chloride on slowly adapting and rapidly adapting receptors of the rabbit lung.

Effects of gadolinium chloride, an inhibitor of stretch-activated channels, on the responses of slowly adapting receptors (SARs) and rapidly adapting receptors (RARs) to hyperinflation were investigated. The increase in activity of RARs resulting from sustained elevations of left atrial pressure (LAP) was also assessed with gadolinium chloride application. Action potentials (AP) of SARs and RARs during hyperinflation were recorded from the vagus nerve of anesthetized New Zealand White rabbits before and after application of gadolinium chloride (20mM) directly on the receptor area of the nerve endings. There was a significant reduction of activity in SARs (n = 9) and RARs (n = 7) after application of gadolinium chloride. Activity of RARs (n = 6) increased when the LAP was elevated by 5 and 10 mmHg. This effect was abolished after gadolinium chloride was applied to receptor endings and the activity was restored when gadolinium chloride was removed. This suggests that stretch-activated channels play a role in SARs and RARs activity.

Action Potentials↗
PubMed2005

Fumonisin B1 hepatotoxicity in mice is attenuated by depletion of Kupffer cells by gadolinium chloride.

Fumonisin B1 (FB1) is a toxic and carcinogenic mycotoxin produced by Fusarium verticillioides found on corn worldwide. The biological effects of FB1 are attributed to sphingolipid metabolism disruption as a result of ceramide synthase inhibition. Tumor necrosis factor alpha (TNFalpha) is an important modulator of FB1 hepatotoxicity. Kupffer cells are major source of cytokine production in liver. In the present study we investigated the effects of Kupffer cell depletion by gadolinium on FB1 hepatotoxicity in female BALB/c mice. Mice were given saline or 50 mg/kg of gadolinium chloride once via the tail vein; 16 h later they were treated with subcutaneous injections of vehicle or 2.25 mg/kg/day FB1 in saline for three successive days. Gadolinium significantly attenuated FB1-induced increases in the activities of circulating alanine aminotransferase and aspartate aminotransferase and reduced the FB1-induced hepatocyte apoptosis and free sphinganine accumulation in liver. Both gadolinium and FB1 treatments individually increased the expression of selected cell signal factors; e.g., TNFalpha, TNF receptor 1, TNF-related apoptosis-inducing ligand, lymphotoxin beta, interferon gamma, and transforming growth factor beta1; gadolinium chloride did not alter FB1-induced expression of the above genes. Results indicated that Kupffer cells play a role in FB1 hepatotoxicity. Decreased FB1-induced sphinganine accumulation and increased protective TNFalpha signaling by gadolinium chloride may in part account for its ameliorating effect on FB1 liver damage.

Alanine Transaminase↗
PubMed2003

Gadolinium-enhanced MRI in the evaluation of minimally invasive treatments of the prostate: correlation with histopathologic findings.

OBJECTIVES: To explore the use of magnetic resonance imaging (MRI) with gadolinium enhancement as a noninvasive method to image the extent of ablation after minimally invasive treatment. Minimally invasive methods for ablating prostatic tissue have emerged as a viable option in the treatment of prostate disease. As these devices enter the mainstream of patient care, imaging methods that verify the exact location, extent, and pattern of the ablation are needed. METHODS: Nineteen patients with prostate cancer were evaluated. All received some type of minimally invasive treatment, post-treatment gadolinium-enhanced MRI sequences, and radical retropubic prostatectomy for histopathologic evaluation. Visual comparisons of gadolinium defects and areas of coagulation necrosis as seen on histopathologic evaluation were made by us. Volumetric and two-dimensional area measurements of the ablation lesions were also compared for correlation between the MRI and histopathologic results. RESULTS: Gadolinium-enhanced MRI could be matched to histopathologic findings by visual comparison in 17 of the 19 cases. Surgically distorted histopathologic specimens and a small periurethral lesion caused 2 patients to have MRI and histopathologic results that could not be matched. Complete volumetric measurements were available for 16 of the 19 patients and correlated strongly (r = 0.924). The two-dimensional area data for all patients also showed significant correlation (r = 0.886). CONCLUSIONS: Correlation with histopathologic findings showed gadolinium-enhanced MRI to be useful for determining the location, pattern, and extent of necrosis caused within the prostate by minimally invasive techniques. Gadolinium-enhanced MRI gives the urologist a useful tool to evaluate the effectiveness of new minimally invasive therapies.

Adenocarcinoma↗
PubMed1999

MRI of normal and abnormal duodenum using Half-Fourier Single-Shot RARE and gadolinium-enhanced spoiled gradient echo sequences.

The objective of this research was two-fold: First, to describe the normal and abnormal MR appearances of the duodenum using combined Half-Fourier Acquisition Single Shot RARE (HASTE) and gadolinium-enhanced standard and fat suppressed spoiled gradient echo (SGE) sequences. The second objective was to assess the ability of these combined sequences to detect and characterize duodenal diseases. MR examinations were performed on fifty consecutive patients with no clinical history of duodenal diseases, who were 1) imaged with HASTE and gadolinium-enhanced standard and fat suppressed SGE sequences and 2) referred to MR examination for reasons other than duodenal diseases, and were reviewed retrospectively to determine the normal MR appearances of the duodenum. A second population of patients with abnormal duodenum who were imaged with the same MR sequences were included in the second part of this study. This population was composed of 20 consecutive patients with subsequently proven duodenal abnormalities, including: malrotation (2), diverticula (4), intussusception (1), sprue (1), polyps (2), neurofibroma (1), lymphoma (1), Zollinger Ellison syndrome (1), metastatic disease (1), Crohn's disease (1), and wall thickening and duodenitis (5). Normal measurements of the duodenum are described. Abnormalities of wall thickness and duodenal masses required combined HASTE and gadolinium-enhanced SGE images to evaluate well. Abnormalities of the bowel lumen (e.g., diverticula and intussusception), and developmental variants (e.g., malrotation), were sufficiently visualized on HASTE images alone. Bowel inflammation was best shown on gadolinium-enhanced fat suppressed SGE images. HASTE and gadolinium-enhanced fat suppressed SGE sequences are complementary techniques for the demonstration of normal and abnormal duodenum. The combined use of both sequences allows evaluation of different aspects of bowel diseases; abnormalities of position, lumen, and contents are well shown on HASTE, while inflammation is best shown on gadolinium enhanced fat suppressed SGE, and wall thickening and masses are best evaluated with the combined use of both techniques.

Adolescent↗
PubMed2002

Validation of injection parameters for catheter-directed intraarterial gadolinium-enhanced MR angiography.

RATIONALE AND OBJECTIVES: Catheter-directed intraarterial (IA) injections of gadolinium contrast agents may be used during endovascular interventions with magnetic resonance (MR) imaging guidance. Injection protocols require further validation. Using a flow phantom and swine, the authors aimed to (a) measure the optimal arterial gadolinium concentration ([Gd]) required for MR angiography and (b) validate a proposed IA injection protocol for gadolinium-enhanced MR angiography. MATERIALS AND METHODS: For in vitro experiments, the authors placed a catheter in the aorta of an aorto-renal-iliac flow phantom. Injected [Gd], injection rates, and aortic blood flow rates were varied independently for 36 separate IA gadolinium injections. The authors performed 2D and 3D MR angiography with a fast spoiled gradient-recalled echo sequence. For subsequent in vivo experiments, they selectively placed catheters within the aorta, renal artery, or common iliac artery of three pigs. Injection rate and injected [Gd] were varied. The authors performed 32 separate IA gadolinium injections for 2D MR angiography. Signal-to-noise ratios (SNRs) were compared for the various combinations of injection rate and injected [Gd]. RESULTS: In vitro, an arterial [Gd] of 2%-4% produced an optimal SNR for 2D MR angiography, and 3%-5% was best for 3D MR angiography. In swine, an arterial [Gd] of 1%-4% produced an optimal SNR. In the phantom and swine experiments, SNR was maintained at higher injection rates by inversely varying the injected [Gd]. CONCLUSION: Dilute arterial [Gd] is required for optimal IA gadolinium-enhanced MR angiography. To maintain an optimal SNR, injection rates and injected [Gd] should be varied inversely. The postulated injection protocol was validated.

Animals↗
PubMedDate not supplied

Gadolinium-DOTA enhanced MR imaging of intracranial lesions.

Gadolinium 1,4,7,10-tetraazacyclododecane-N,N',N",N"'-tetraacetic acid (Gd-DOTA) is the first of a new class of macrocyclic paramagnetic magnetic resonance (MR) contrast agents (gadolinium cryptelates) to be used in clinical practice. Gadolinium-DOTA possesses relaxation properties similar to those of gadolinium diethylene triamine pentaacetic acid (Gd-DTPA). We report our initial clinical experience in 38 patients with intracranial lesions studied with MR before and after injection of Gd-DOTA. Diseases included primary and metastatic brain tumor, cerebral infarct, vascular malformation, meningioma, hemangiopericytoma, schwannoma, and pituitary macroadenoma. Gadolinium-DOTA was administered intravenously in a dosage of 0.1 mmol/kg body weight. All studies were performed on a superconductive 0.5 T system. As compared to noncontrast T1- and T2-weighted images (WI), Gd-DOTA enhanced T1 WI were useful in defining the anatomy of malignant intraaxial tumors (high-grade glioma, metastasis) and in tumor versus edema differentiation. Low-grade gliomas did not enhance; in these cases the precontrast T2-weighted sequence was found to be more informative. In post-operative patients, Gd-DOTA allowed us to demonstrate residual tumor or tumor recurrence. Extraaxial tumors (meningioma, hemangiopericytoma, neuroma) enhanced markedly, presumably reflecting tumor vascularity. In our experience, the use of Gd-DOTA improves the anatomic definition of cerebral lesions and in some cases increases both MR sensitivity and specificity. We found Gd-DOTA to be a well tolerated and effective paramagnetic contrast agent. Gadolinium-DOTA can be considered as an alternative water-soluble MR contrast agent to Gd-DTPA.

Adult↗
PubMedDate not supplied

Focal nodular hyperplasia of the liver: assessment of hemodynamic and angioarchitectural patterns with gadolinium chelate-enhanced 3D spoiled gradient-recalled MRI and maximum intensity projection reformatted images.

PURPOSE: Our goal was to determine the relative merits of gadolinium chelate-enhanced 3D spoiled gradient-recalled (GRE) MRI versus maximum intensity projection (MIP) reformatted images in assessing the morphologic, hemodynamic, and angioarchitectural patterns of focal nodular hyperplasia (FNH) of the liver. METHOD: Ten consecutive patients with 10 FNHs had prospectively gadolinium chelate-enhanced 3D spoiled GRE MRI (TR/TE/FA = 10.1/1.9/30) of the liver at 1.5 T. Gadolinium chelate-enhanced 3D spoiled GRE source images and MIP reformatted images were separately analyzed with respect to morphologic and hemodynamic features and angioarchitectural patterns by two independent readers. RESULTS: Gadolinium chelate-enhanced 3D spoiled GRE source images and MIP reformatted images showed the most intense degrees of enhancement of FNH during the arterial phase of hepatic parenchymal enhancement in all cases. Gadolinium chelate-enhanced 3D spoiled GRE source images were superior to MIP reformatted images for the assessment of morphologic features of FNH (p < 0.02). MIP reformatted images were superior to the corresponding source images for showing the main branches of the hepatic artery, an arterial branch going to the FNH, and a small artery within the FNH radiating to peripheral areas (p < 0.05). There was excellent agreement between the two observers for analysis of the MIP reformatted images (p < 0.05). CONCLUSION: The combination of gadolinium chelate-enhanced 3D spoiled GRE source images and MIP reformatted images allows the analysis of morphologic, hemodynamic, and angioarchitectural patterns of FNH of the liver. Further study and comparison with currently applied strategies will determine the value of these two techniques for diagnosing FNH of the liver.

Adult↗
PubMed1998

Findings of retinitis on gadolinium-enhanced turbo fluid-attenuated inversion recovery images.

PURPOSE: This study sought to determine the findings of retinal inflammation on gadolinium-enhanced turbo fluid-attenuated inversion recovery (tFLAIR) images. METHODS: Five patients with retinal abnormalities (acquired immunodeficiency syndrome complicated by cytomegalovirus retinitis, two patients; lymphoma complicated by Herpes zoster retinitis, one patient; and diabetic retinopathy, two patients) were identified on routine brain magnetic resonance imaging examinations performed with gadolinium-enhanced tFLAIR; five healthy subjects were retrospectively reviewed for comparison. Retinal signal features and thickness were evaluated comparing gadolinium-enhanced tFLAIR with turbo spin-echo T2-weighted and spin-echo T1-weighted images with and without gadolinium. RESULTS: Abnormal retinal thickening and hyperintensity were most conspicuous on gadolinium-enhanced tFLAIR images. Unenhanced T1-weighted images failed to demonstrate any abnormalities. In the enhanced tFLAIR and T1-weighted images, retinal thickness greater than 1.2 mm was abnormal. Abnormal retinal contour and signal was most apparent on the tFLAIR images. CONCLUSIONS: Of the sequences studied, gadolinium-enhanced tFLAIR images were found to be the best in identifying incidental retinitis and diabetic retinopathy discovered on routine brain magnetic resonance imaging examinations.

Adult↗
PubMed2003

Visualization of spinal injection procedures using gadolinium contrast.

STUDY DESIGN: A series of six case reports. OBJECTIVE: The case reports demonstrate successful use of gadolinium contrast for visualization of spinal injection procedures. SUMMARY OF BACKGROUND DATA: A variety of spinal injection procedures were performed with gadolinium contrast. Adequate visualization was accomplished with gadolinium in performing these injections and demonstrated that it is a viable alternative to nonionic iodinated contrast materials. MATERIALS AND METHODS: The case reports included a chart review, performance of spinal injections with gadolinium under fluoroscopic guidance, and postprocedure follow-up at 2 and 12 weeks. RESULTS: Gadolinium was visible under fluoroscopy in all six cases, demonstrating its value in performing spinal injection procedures as an alternative to nonionic iodinated contrast materials. CONCLUSION: Gadolinium is a viable alternative to nonionic iodinated contrast materials for visualization of spinal injection procedures.

Contrast Media↗
PubMed2004

Aortoiliac gadolinium-enhanced CT angiography: improved results with a 16-detector row scanner compared with a four-detector row scanner.

PURPOSE: To assess the level of vascular enhancement of gadolinium-enhanced aortoiliac computed tomographic (CT) angiography with a 16-detector row CT scanner and to compare it with the results of previous similar studies that used four-detector row CT units. MATERIALS AND METHODS: Eleven gadolinium-enhanced CT angiograms were obtained in 10 consecutive patients with contraindication to iodinated contrast medium with use of a 16-detector row CT scanner. In the region of interest, attenuation measurements (in HU) were obtained from the proximal abdominal aorta to the common femoral arteries during unenhanced, gadolinium-enhanced, and delayed acquisitions. The results were compared to those in the 15 consecutive patients who most recently had similar examinations performed on a four-detector row CT unit. Phantom studies with diluted gadolinium were conducted to compare attenuation between CT units. RESULTS: On four-detector row CT, throughout the scan length, mean enhancement values were 53.8 HU +/- 5.3 and 15.0 HU +/- 2.6 for gadolinium-enhanced and delayed series, respectively. For the 16-detector row CT unit, they were 76.1 HU +/- 3.4 and 21.3 HU +/- 1.3, respectively. As a result of a shorter scan time and a more optimal start time, the 16-detector row CT unit provided significantly greater and more consistent enhancement throughout the scan length compared with the four-detector row CT unit (P =.0106). Similar structures had significantly greater enhancement when 120 kV was applied instead of 140 kV (P =.0495) CONCLUSION: The 16-detector row CT scanner improved gadolinium-enhanced CT angiography results compared with the four-detector row CT unit.

Aged↗
PubMed1991

Block of receptor response in the stretch receptor neuron of the crayfish by gadolinium.

The trivalent lanthanide gadolinium was found to block the mechanotransducer response in the stretch receptor neuron of the crayfish. At normal calcium concentration (13.5 mM) a 50 per cent block of the receptor current was found at 395 +/- 59 (mean +/- SD) microM gadolinium. At a calcium concentration of 1.35 mM a 50 per cent block of the receptor current was obtained at 103 +/- 14 (mean +/- SD) microM gadolinium. The potential activated potassium current was also affected by gadolinium. At 200 microM the amplitude of the peak outward current as a result of a 90 mV positive potential step was decreased by about 40 per cent. The fast inward sodium current was decreased less than 10 per cent by gadolinium. It is concluded that in the crayfish stretch receptor gadolinium blocks the receptor current, reflecting block of stretch-activated channels, but at higher concentrations than have been described for other stretch-activated channels. In addition the outward rectifier potassium current is also blocked reflecting a block of potassium channels.

Animals↗
PubMed2002

Crohn disease with endoscopic correlation: single-shot fast spin-echo and gadolinium-enhanced fat-suppressed spoiled gradient-echo MR imaging.

PURPOSE: To compare T2-weighted breath-hold single-shot fast spin-echo (SE) and gadolinium-enhanced spoiled gradient-echo (GRE) MR imaging with contrast material administered orally and rectally for evaluating patients with Crohn disease. MATERIALS AND METHODS: Twenty-eight patients with Crohn disease received 2% barium sulfate and water enema. The abdomen and pelvis were imaged with transverse and coronal single-shot fast SE and gadolinium-enhanced spoiled GRE MR imaging. Two radiologists reviewed the two types of images for bowel disease. The extent, severity, and conspicuity of the disease were determined. Proof of bowel disease at MR imaging was compared with that at endoscopy, barium study, and surgery. Statistical analysis was performed with the McNemar test. RESULTS: Twenty-five of 28 patients had proven abnormal bowel segments. The per-patient sensitivity of gadolinium-enhanced spoiled GRE MR imaging for the two radiologists was 100% and 96% versus 60% and 60% (P <.05) with single-shot fast SE MR imaging. Gadolinium-enhanced spoiled GRE MR images depicted more segments (54 and 52 of 61 segments; sensitivity, 89% and 85%, respectively) of the diseased bowel than did single-shot fast SE MR images (31 and 32 of 61 segments; sensitivity, 51% and 52%, respectively; P <.001). Severity of Crohn disease was correctly depicted at gadolinium-enhanced spoiled GRE imaging in 93% of patients versus in 43% of patients at single-shot fast SE imaging. CONCLUSION: In patients with Crohn disease, gadolinium-enhanced fat-suppressed spoiled GRE MR imaging better depicted the extent and severity of intestinal disease compared with single-shot fast SE imaging.

Adult↗
PubMed2002

Gadolinium chelates in angiography and interventional radiology: a useful alternative to iodinated contrast media for angiography.

Gadolinium has physical properties that are well suited for radiographic imaging. Digital subtraction angiography with a gadolinium chelate as contrast medium can provide images of suitable quality for diagnosis and intervention. The overall safety profile of gadolinium-based contrast media is excellent. In particular, these contrast media are well tolerated in patients with renal insufficiency when administered intraarterially in doses of less than 0.3-0.4 mmol per kilogram body weight, with a decreased incidence of contrast medium-induced nephropathy, as compared with similar volumes of iodinated contrast material. The currently available formulations of gadolinium chelates can be injected safely into every arterial and venous structure. However, substantial data are lacking on the intraarterial use of gadolinium in patients with renal insufficiency, particularly at doses that exceed those routinely used in magnetic resonance angiography. Gadolinium chelates in appropriate volumes are useful alternative contrast media in selected high-risk patients undergoing angiographic studies.

Angiography↗
PubMed2003

Imaging of osteoid osteoma with dynamic gadolinium-enhanced MR imaging.

PURPOSE: To compare dynamic gadolinium-enhanced T1-weighted magnetic resonance (MR) imaging with nonenhanced T1-weighted and T2-weighted MR imaging and thin-section computed tomography (CT) for the demonstration of osteoid osteomas. MATERIALS AND METHODS: The images of 11 patients with pathologically proven osteoid osteomas who underwent nonenhanced MR imaging, dynamic gadolinium-enhanced MR imaging, and CT were retrospectively reviewed. Images obtained with all three techniques were scored for conspicuity of the osteoid osteoma relative to the surrounding bone. Time-enhancement curves were generated from signal intensity measurements of these lesions and the adjacent bone marrow. The mean imaging scores of the four techniques were compared, and the statistical significance was calculated by using a linear model with terms for method and patient. Pairwise comparisons were made by using the Tukey-Kramer adjustment for multiple comparisons. RESULTS: Compared with CT, dynamic gadolinium-enhanced MR imaging demonstrated the osteoid osteoma equally well in eight of 11 patients and with better conspicuity in three of 11 patients, although this difference was not statistically significant (P =.69). The dynamic gadolinium-enhanced MR images demonstrated the osteoid osteomas significantly better than the nonenhanced T1-weighted (P <.001) and T2-weighted (P <.001) MR images. On the dynamic gadolinium-enhanced MR images, nine (82%) of 11 patients had peak enhancement of the osteoid osteoma in the arterial phase with early partial washout, compared with slower, progressive enhancement of the adjacent marrow. This resulted in greatest lesion to marrow contrast material enhancement in the arterial phase. One osteoid osteoma had peak enhancement in the venous phase, and one showed progressive enhancement through all phases to 150 seconds. CONCLUSION: Osteoid osteomas can be imaged with greater conspicuity by using dynamic gadolinium-enhanced instead of nonenhanced MR imaging and with conspicuity equal to or better than that obtained with thin-section CT.

Adolescent↗
PubMed2005

Safety and effectiveness of gadolinium-enhanced multi-detector row spiral CT angiography of the chest: preliminary results in 37 patients with contraindications to iodinated contrast agents.

PURPOSE: To prospectively evaluate the safety and effectiveness of gadolinium-enhanced multi-detector row spiral computed tomographic (CT) angiography of the pulmonary circulation by using two gadolinium doses in patients with contraindications to iodinated contrast agents. MATERIALS AND METHODS: Study was approved by the Ethics Committee, and written informed consent was obtained. Thirty-seven patients (20 men, 17 women) with contraindications to iodinated contrast agents (allergic reactions, n = 27; impaired renal function, n = 10) underwent CT angiography of the pulmonary circulation in search of acute pulmonary embolism (n = 28) or for management of tumoral disease (n = 9). CT angiography was performed (a) with four-detector row (n = 19) or 16-detector row (n = 18) scanners; (b) at randomly assigned gadolinium doses of either 0.3 mmol per kilogram of body weight (n = 19) or 0.4 mmol/kg (n = 18); and (c) with a systematic evaluation of clinical and biologic tolerance of gadolinium. Comparison of percentages between group 1 and group 2 scans was performed with the chi2 or the Fisher exact test. An unpaired Wilcoxon rank sum test was used for numeric variables. P < .05 was considered to indicate a significant difference. RESULTS: The mean (+/- standard deviation) volume of gadopentetate dimeglumine administered in the overall study group was 48 mL +/- 9.6 (range, 29-65 mL). The level of maximal enhancement in the pulmonary arteries was significantly higher in group 2 than in group 1 (215.8 HU +/- 95 vs 141.3 HU +/- 44) (P = .02) and was maintained throughout the entire region of interest in a greater number of examinations in group 2 than in group 1 (n = 16 [89%] vs n = 2 [10.5%]) (P < .0001). The number of diagnostic CT angiograms was significantly higher in group 2 than in group 1 (n = 17 [94%] vs n = 13 [68%]) (P = .007). Significant but transient reduction of creatinine clearance was observed in one patient with preexisting moderate chronic renal failure (0.3 mmol/kg gadolinium dose). CONCLUSION: High-quality gadolinium-enhanced CT angiograms require the use of 16-detector row CT technology; the doses administered did not alter the renal function except transiently in one patient.

Adolescent↗