[Magnetic resonance tomographic screening studies of the bone marrow with gradient echo sequences: (I) the contrast relations of phase-identical and phase-shifted gradient echo sequences. Studies on probands and pathological-anatomical preparations]

Diagnostic value of MRI in comparison to scintigraphy, PET, MS-CT and PET/CT for the detection of metastases of bone

The initial localization of metastases in the bone in patients with solid tumors has a relatively good prognosis in comparison with visceral metastasization. The early detection of bone marrow metastases allows for a rapid initiation of therapy and a subsequent reduction in the morbidity rate. Modern MRI is superior to the 30-year-old skeletal scintigraphy and bone marrow scintigraphy with respect to sensitivity, specificity, as well as the extent of osteal metastasis. MRI provides substantial, therapy-relevant additional information. MSCT plays an important role in the management of cancer patients in clinical routine and gives an excellent survey of the axial skeleton by demonstrating osteolytic and osteoblastic metastases. Extensive comparative studies of MRI with 18F-FDG-PET and 18F-fluoride-PET have not yet been carried out. Whole body MRI is a very promising new staging method for the oncological diagnosis of solid tumors and the detection of osteal metastases. The adoption of 18F-FDG-PET and 18F-fluoride-PET FDG as well as the side by side PET-CT image fusion and the two in one PET/CT examinations appears to be slightly less sensitive to whole body MRI in the detection of osteal metastases. Larger, prospective multicenter studies are necessary to establish these as new, promising methods for the detection of osteal metastases.

Initial experience with dynamic MR imaging in evaluation of normal bone marrow versus malignant bone marrow infiltrations in humans

The purpose of this study was (a) evaluation of dynamic contrast-enhanced MR imaging of normal bone marrow versus malignant bone marrow infiltrations in patients with proven B-cell-type chronic lymphocytic leukemia (B-CLL) and (b) correlation with the clinical stage according to Binet (stages A, B, C) and response to therapy. Bone marrow imaging of the lumbar spine, pelvis, and proximal femurs was performed at 1.5 T in 45 patients without known malignancy and in 30 patients with B-CLL. The differences between opposed-phase and in-phase dynamic gradient-echo sequences before and up to 10 minutes after intravenous application of .1 mmol/kg body weight of gadolinium-diethylenetriamine penta-acetic acid (Gd-DTPA) were evaluated in normal bone marrow. The contrast-enhancement patterns of normal and malignant bone marrow were compared using the opposed-phase dynamic gradient-echo sequence. Ten of the patients with bone marrow infiltrations (Binet stage C) additionally underwent MR imaging follow-up during therapy. Opposed-phase gradient echo sequences demonstrated a signal decrease of normal bone marrow, and in-phase gradient echo sequences demonstrated a signal increase of normal bone marrow after administration of Gd-DTPA. The dynamic signal intensity time courses differed significantly (P < .05) between Binet stages B and C and controls as well as among the three Binet stages of B-CLL. In the 10 patients followed during therapy, MR imaging sensitively demonstrated response (n = 6), nonresponse (n = 2), or relapse after initial response (n = 2). In out-of-phase imaging, both normal bone marrow and initial bone marrow infiltration in CLL stage Binet A show signal decrease after administration of contrast agent, whereas there is increase in signal intensity in higher-grade bone marrow infiltration in Binet stage B or C disease. The signal loss of normal bone marrow in out-of-phase imaging is a phase effect rather than a T2* effect. The differentiation of initial from higher-grade bone marrow infiltration on out-of-phase images relies solely on a shift in the fat/water ratio.

CT-guided intraarticular corticosteroid injection into the sacroiliac joints in patients with spondyloarthropathy: indication and follow-up with contrast-enhanced MRI

PURPOSE

Our goal was to prospectively study the therapeutic efficacy of CT-guided intraarticular corticosteroid instillation of inflamed sacroiliac joints (SIJs) in patients with spondyloarthropathies and to evaluate the role of MRI as a procedure for establishing the indication and for therapeutic follow-up.

METHOD

A total of 103 CT-guided corticosteroid injections of the SIJs were performed in 66 patients with inflammatory back pain (IBP): 37 bilateral, 29 unilateral. All patients did not respond to an immediately preceding 4 week nonsteroidal antiinflammatory therapy. Forty milligrams of a crystalline long-acting corticoid was instilled in each joint. All 66 patients underwent continuous clinical follow-up at 10 to 12 week intervals after corticosteroid injection to a maximum of 18 months. The degree of subjective complaints before and after the intervention was recorded using a analogue scale (0 = no pain, 10 = unbearable pain). Dynamic contrast-enhanced (Gd-DTPA, 0.1 mmol/kg body wt) MRI with quantitative determination of contrast enhancement was performed in all patients before the therapeutic intervention and in 38 patients at 8 +/- 4 months.

RESULTS

Sixty-one of the 66 study patients (92.5%) showed a statistically significant abatement of subjective complaints from 8.8 +/- 1.3 to 3.3 +/- 2.3 (p < 0.01) at 1.7 +/- 1.1 weeks after intervention, and this improvement lasted for 10 +/- 5 months. The percentage contrast enhancement at dynamic MRI likewise showed a significant reduction from 100.3 +/- 48% before to 44.3 +/- 36.1% after intraarticular cortisone administration (p < 0.01).

CONCLUSION

CT-guided intraarticular corticosteroid instillation in the SIJs may be regarded as an effective therapy for florid sacroiliitis. The severity of inflammation and the response to therapy can be determined quantitatively by dynamic MRI.

Bone marrow after autologous blood stem cell transplantation and total body irradiation: magnetic resonance and chemical shift imaging

Magnetic resonance studies of the lumbar, pelvic, and femoral bone marrow were performed in 10 patients after autologous blood stem cell transplantation, including total body irradiation and myeloablative chemotherapy. The posttreatment interval varied between 2 and 6 yr. The appearance on T1-weighted images and the quantitative data obtained from chemical shift imaging (relative fat signal) were compared to 10 age-matched healthy volunteers. The classification of the T1-weighted images yielded no significant differences between the two groups. Chemical shift imaging by determination of the relative fat signal was able to detect a significant fatty replacement of the patients' lumbar (p < .002) and pelvic marrow (p < .01), showing the clinically inapparent decreased cellularity of the bone marrow. This difference did not change within the interval of 2-6 yr after transplantation.