Biomedical subjects

M Taupitz

Publications and source records attributed to M Taupitz.

80 records · Page 5Linked to original sources

PubMed1991

Focal nodular hyperplasia of the liver: MR findings in 35 proved cases.

MR images of 28 patients with 35 lesions of hepatic focal nodular hyperplasia were reviewed to determine the frequency of findings considered typical of this condition (isointensity on T1- and T2-weighted pulse sequences, a central hyperintense scar on T2-weighted images, and homogeneous signal intensity). Fifteen lesions were imaged at 0.6 T with T1- and T2-weighted spin-echo (SE) pulse sequences; 20 lesions were imaged at 1.5 T with T1-weighted SE and gradient-echo pulse sequences and T2-weighted SE pulse sequences. Diagnosis of focal nodular hyperplasia was made pathologically in 25 patients, with nuclear scintigraphy in four, and with follow-up imaging in six. Only seven lesions (20%) were isointense relative to normal liver on both T1- and T2-weighted images. On T1-weighted SE images, 21 lesions (60%) were isointense relative to normal liver, 12 (34%) were hypointense, and two (6%) were hyperintense. On T2-weighted SE images, 12 lesions (34%) were isointense and 23 (66%) were hyperintense relative to normal liver. A central scar was present in 17 lesions (49%) and was hypointense relative to the lesion on T1-weighted images and hyperintense on T2-weighted images. Twenty lesions (57%) were of homogeneous signal intensity throughout the lesion, except for the presence of a central scar. All three MR imaging characteristics were present in three cases (9%). We conclude that hepatic focal nodular hyperplasia has a wide range of signal intensity on MR imaging.

Adult↗

PubMedDate not supplied

Contrast-enhanced MR imaging of liver and spleen: first experience in humans with a new superparamagnetic iron oxide.

The aim of this prospective study was to obtain the first human safety and magnetic resonance (MR) imaging results with a new formulation of superparamagnetic iron oxide (SPIO) (SHU 555 A). The SPIO was tested at four iron doses, from 5 to 40 mumol/kg. Laboratory tests and clinical measurements were done in 32 healthy volunteers for up to 3 weeks after administration. MR imaging at 1.5 T was performed before and 8 hours to 14 days after fast intravenous injection (500 mumol Fe/min) of the SPIO (six subjects per dose). Results of this phase I study demonstrate that SHU 555 A at a concentration of 0.5 mol Fe/L was well tolerated. A dose-dependent minor increase in activated partial thromboplastin time, which remained within the normal range, was seen. All doses of SPIO caused a signal loss in both liver and spleen (P < .05) with a spin-echo sequence (TR = 2,300 msec, TE = 45 msec). The signal losses in the liver 8 hours after contrast agent injection were 58%, 79%, 82%, and 87% for the 5, 10, 20, and 40 mumol Fe/kg doses, respectively. The corresponding signal losses in the spleen were 23%, 45%, 65%, and 78%, respectively. The doses that reduced signal intensity by half were 3.1 mumol Fe/kg for the liver and 12.8 mumol Fe/kg for the spleen. The results suggest that the new SPIO formulation is a safe and efficient MR contrast agent.

Adult↗

PubMedDate not supplied

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.

Adult↗

PubMedDate not supplied

Differentiation of hepatic hemangiomas from metastases by dynamic contrast-enhanced MR imaging.

Twenty-nine patients with hepatic hemangiomas (n = 14) and hepatic metastases (n = 15) underwent magnetic resonance (MR) imaging prior to and after an intravenous bolus injection of Gd-diethylenetriamine pentaacetic acid (0.2 mmol/kg). Before contrast application, a T2-weighted spin echo sequence (SE 1,600/105) and a T1-weighted gradient echo sequence (GE 315/14/90 degrees pulse angle) were performed. Beginning with injection of the contrast agent, a dynamic study was conducted for 10 min using a moderately T1-weighted gradient echo sequence (GE 40/14/40 degrees) with an acquisition time of 10.2 s per image. Delayed (11 min) and late (60 min) postcontrast images were obtained using a T1-weighted sequence (GE 315/14/90 degrees). In the dynamic study (0-10 min) the hemangiomas were characterized by peripheral contrast enhancement and a subsequent hyperintense fill-in. The metastases showed very mixed patterns of enhancement after contrast administration, and their signal intensity remained low compared with that of the hepatic tissue. In the delayed postcontrast examination (11 min) the hemangiomas had a very high and homogeneous signal intensity and the metastases were characterized by an inhomogeneous, hypointense to isointense signal. The contrast between tumor and liver [signal-difference-to-noise ratio (SD/N)] was higher for all hemangiomas than it was for the metastases. In the T2-weighted precontrast examination, on the other hand, five hemangiomas and seven metastases showed an overlap in the SD/N. The late postcontrast images (60 min) did not yield any further diagnostic information. We conclude that the combination of a dynamic MR study with delayed postcontrast T1-weighted imaging is a useful method of diagnosing hepatic hemangiomas.

Adult↗

PubMedDate not supplied

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.

Adult↗

PubMedDate not supplied

Dynamic and quantitative assessment of tracheomalacia by electron beam tomography: correlation with clinical symptoms and bronchoscopy.

PURPOSE: The purpose of this study was to evaluate the performance of electron beam tomography (EBT) in the dynamic and quantitative assessment of tracheal collapse in tracheomalacia. METHOD: Eight patients with suspected tracheomalacia were evaluated by EBT, and the results were correlated with both clinical symptoms and bronchoscopy. To validate this technique, an EBT phantom study preceded the patients' examination. A dynamic imaging sequence consisting of 20 50-ms scans obtained at 0.5 s intervals during a 10 s period was performed while the patient followed an instructed breathing maneuver. RESULTS: Good correlation between EBT data and clinical symptoms was found in all patients. In comparison to bronchoscopic findings, EBT results correlated well in three, showed limited correlation in three patients, and no correlation in one case. CONCLUSION: EBT with its short scanning time may be regarded as an accurate noninvasive method to dynamically evaluate tracheomalacia.

Adult↗

PubMedDate not supplied

Rib artifacts in electron beam tomography: incidence and severity without and with the cone beam reconstruction algorithm.

Electron beam tomography (EBT) may be compromised by rib artifacts. Two hundred forty-seven abdominal studies were performed without (Group A, n = 222) or with (Group B, n = 25) the cone beam algorithm. One hundred eighty-six (83.8%) and nine (36%) studies of Groups A and B, respectively, displayed some level of artifact. In Groups A and B, major, minor, and no artifacts were found in 115 (51.5%) and 0 (0%), 71 (32.3%) and 9 (36%), and 36 (16.2%) and 16 (64%) patients, respectively (p < 0.01). The cone beam algorithm improves EBT studies of the abdomen.

Algorithms↗

PubMedDate not supplied

Use of contrast enhanced magnetic resonance imaging to detect spinal inflammation in patients with spondyloarthritides.

Inflammation of spinal structures is a characteristic feature of the spondyloarthritides (SpA). The term SpA covers patients with inflammatory back pain and/or peripheral arthritis who can be further categorized. Ankylosing spondylitis (AS), the prototype of the SpA, the most frequent inflammatory spinal disease in adults, usually starts in the sacroiliac joints. Pathologic spinal changes occurring in AS are spondylitis, spondylodiscitis and inflammation and ankylosis also at other sites in the axial skeleton. In the later stages of AS such changes can be well recognized by spinal x-rays. In the early disease stages it has been more difficult to analyze the exact anatomic localization of spinal inflammation to date, because conventional imaging systems have only a limited capacity to demonstrate such changes early. There is some evidence that magnetic resonance imaging (MRI) with fat saturation and contrast enhanced MRI are useful to visualize early and late inflammatory changes in the sacroiliac joints. In this paper we report that MRI is also useful to localize the site of inflammation to distinct regions of the spine in AS and other SpA.

Adult↗