Heel pain is a common and frequently disabling clinical complaint that may be caused by a broad spectrum of osseous or soft-tissue disorders. These disorders are classified on the basis of anatomic origin and predominant location of heel pain to foster a better understanding of this complaint. The disorders include plantar fascial lesions (fasciitis, rupture, fibromatosis, xanthoma), tendinous lesions (tendinitis, tenosynovitis), osseous lesions (fractures, bone bruises, osteomyelitis, tumors), bursal lesions (retrocalcaneal bursitis, retroachilleal bursitis), tarsal tunnel syndrome, and heel plantar fat pad abnormalities. With its superior soft-tissue contrast resolution and multiplanar capability, magnetic resonance (MR) imaging can help determine the cause of heel pain and help assess the extent and severity of the disease in ambiguous or clinically equivocal cases. Careful analysis of MR imaging findings and correlation of these findings with patient history and findings at physical examination can suggest a specific diagnosis in most cases. The majority of patients with heel pain can be successfully treated conservatively, but in cases requiring surgery (eg, plantar fascia rupture in competitive athletes, deeply infiltrating plantar fibromatosis, masses causing tarsal tunnel syndrome), MR imaging is especially useful in planning surgical treatment by showing the exact location and extent of the lesion.

Early diagnosis and treatment have been recognized as essential for improving clinical outcomes in patients with early rheumatoid arthritis. However, diagnosis is somewhat difficult in the early stages of the disease because the diagnostic criteria were developed from data obtained in patients with established rheumatoid arthritis and therefore are not readily applicable. Magnetic resonance (MR) imaging is increasingly being used in the assessment of rheumatoid arthritis due to its capacity to help identify the key pathologic features of this disease entity at presentation. MR imaging has demonstrated greater sensitivity for the detection of synovitis and erosions than either clinical examination or conventional radiography and can help establish an early diagnosis of rheumatoid arthritis. It also allows the detection of bone marrow edema, which is thought to be a precursor for the development of erosions in early rheumatoid arthritis as well as a marker of active inflammation. In addition, MR imaging can help differentiate rheumatoid arthritis from some clinical subsets of peripheral spondyloarthropathies by allowing identification of inflammation at the insertions of ligaments and tendons (enthesitis).

Glomerular number (N_g) is considered a major determinant of renal function and outcome. In the dog, it has been shown that Ng can be estimated with reasonable precision in vivo by means of a renal biopsy and magnetic resonance imaging (MRI). Thus, this method was applied to study anatomoclinical correlations in stable human renal transplants. Thirty-nine stable renal transplants were included. A protocol renal allograft biopsy was done at 4 mo. Biopsies were evaluated according to Banff criteria. Glomerular volume fraction (Vv_glom/cortex) was measured by means of a point-counting method, and mean glomerular volume (V_g) was estimated by means of Weibel and Gomez (V_g-W&G) and maximal profile area (V_g-MPA) methods. MRI was used to estimate renal cortical volume (V_cortex). N_g was calculated as (Vv_glom/cortex × V_cortex)/V_g. GFR was estimated by the inulin clearance. Ten age-matched donor biopsies served as controls for V_g. Histologic diagnosis was as follows: normal (n = 20), borderline (n = 7), acute rejection (n = 1), and chronic allograft nephropathy (n = 11). Vv_glom/cortex was 3.4 ± 1.1%, V_cortex was 167 ± 46 cm³, V_g-W&G was 3.2 ± 1.2 × 10⁶ μm³, and V_g-MPA was 3.3 ± 1.0 × 10⁶ μm³. V_g-W&G in donor and recipient biopsies was not different (3.6 ± 1.1 versus 3.2 ± 1.2 × 10⁶ μm³). Total glomerular number estimated by means of V_g-W&G (N_g-W&G) was 0.73 ± 0.33 × 10⁶ and by V_g-MPA (N_g-MPA) was 0.74 ± 0.31 × 10⁶. A positive correlation between GFR and N_g-W&G (r = 0.47, P = 0.002) was observed. Furthermore, the older the donor, the higher V_g-W&G (r = 0.37, P = 0.01) and the lower N_g-W&G (r = −0.40, P = 0.01). Total glomerular number can be estimated in stable renal allografts by means of a renal biopsy and MRI. Our data show that N_g depends on donor age and positively correlates with GFR. E-mail: 28383xfo@comb.es