Delayed contrast-enhanced MRI of cartilage (dGEMRIC) is a noninvasive technique to study cartilage glycosaminoglycan (GAG) content in vivo. This study evaluates dGEMRIC in patients with preradiographic degenerative cartilage changes. Seventeen knees in 15 patients (age 35-70) with arthroscopically verified cartilage changes (softening and fibrillations) in the medial or lateral femoral compartment, knee pain, and normal weight-bearing radiography were included. MRI (1.5 T) was performed precontrast and at 1.5 and 3 hr after an intravenous injection of Gd-DTPA 2؊ at 0.3 mmol/kg body weight. T 1 measurements were made in regions of interest in medial and lateral femoral cartilage using sets of five turbo inversion recovery images. Precontrast, R 1 (R 1 ‫؍‬ 1/T 1 , 1/s) was slightly lower in diseased compared to reference compartment, indicating increased hydration (P ‫؍‬ 0.01). Postcontrast, R 1 was higher in diseased than in reference compartment at 1.5 hr, 3.45 ؎ 0.90 and 2.64 ؎ 0.58 (mean ؎ SD), respectively (P < 0.01), as well as at 3 hr, 2.94 ؎ 0.60 and 2.50 ؎ 0.37, respectively (P ‫؍‬ 0.01). The washout of the contrast medium was faster in diseased cartilage as shown by a higher R 1 at 1.5 than at 3 hr in the diseased but not in the reference compartment. In conclusion, dGEMRIC can identify GAG loss in early stage cartilage disease with a higher sensitivity at 1.5 than 3 hr. Magn Reson Med 49: 488 -492, 2003.

Topics reviewed include the history, clinical features and prevalence of nephrogenic systemic fibrosis and the current understanding of its pathophysiology. The risk factors for NSF are discussed and prophylactic measures are recommended. The stability of the different gadolinium-based contrast media and the potential long-term effects of gadolinium in the body have also been reviewed.

The negatively charged contrast agent Gd-DTPA 2-distributes inversely to the cartilage fixed charged density. This enables structural cartilage examinations by contrast-enhanced MRI. In line with the development of a clinically applicable protocol for such examinations, this study describes the temporal pattern of Gd-DTPA 2-distribution in femoral knee cartilage at three different doses in healthy volunteers. Nineteen volunteers (ages 21-28 years) were examined with a 1.5T MRI system. Quantitative relaxation rate measurements were made in weight-bearing central parts of femoral cartilage using sets of five turbo inversion recovery images with different inversion times.

Delayed gadolinium-enhanced MRI of cartilage (dGEMRIC) is a new imaging technique to estimate joint cartilage glycosaminoglycan content by T 1 -relaxation time measurements after penetration of the hydrophilic contrast agent Gd-DTPA 2-. This study compares dGEMRIC in age-matched healthy volunteers with different levels of physical activity: Group 1 (n ‫؍‬ 12): nonexercising individuals; Group 2 (n ‫؍‬ 16): individuals with physical exercise averaging twice weekly; Group 3 (n ‫؍‬ 9): male elite runners. dGEMRIC was performed 2 hr after an intravenous injection of Gd-DTPA 2-at 0.3 mmol/kg body weight.

The spleen is generally not considered a challenge to the radiologist. Most often it poses a problem by anomalies or an irregular but normal contrast enhancement; however, a variety of inflammatory, infectious and neoplastic diseases may involve the spleen. CT and ultrasonography are screening modalities for the spleen. For problem solving, MR imaging can be helpful, especially due to its free choice of the imaging plane and because of the high resolution in contrast MR imaging. Splenic angiography as a diagnostic tool has generally been replaced by CT, ultrasound, or MR and is now used as an interventional method, e. g., in non-surgical management of patients with chronic idiopathic thrombocytopenia or in patients with splenic trauma. This article reviews the radiology of the spleen, including anatomy, embryology, splenomegaly, splenic injury, infarction, cysts, tumors, abscesses, sarcoidosis, and AIDS. Knowledge about the use of different imaging modalities and underlying gross and microscopic pathologic features leads to a better understanding of the radiologic findings.