Case report. Crowding and crossbite.
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Adolescent↗
Biomedical subjects
D O Olson
Publications and source records attributed to D O Olson.
Gadolinium-DTPA-enhanced MR imaging of spinal neoplasms: preliminary investigation and comparison with unenhanced spin-echo and STIR sequences.
Unenhanced T1- and T2-weighted spin-echo, short inversion time inversion recovery (STIR), and gadolinium-DTPA (Gd-DTPA)-enhanced spin-echo and STIR imaging techniques were used in 20 patients as part of a multicenter study to assess the safety and efficacy of Gd-DTPA in spinal imaging. Five patients had normal MR scans. Of those with lesions, both Gd-DTPA-enhanced T1-weighted spin-echo and unenhanced STIR scans improved detection and evaluation of spinal tumors over conventional spin-echo methods, particularly T2-weighted spin echo, by providing higher tissue contrast in shorter imaging times. The Gd-DTPA-enhanced T1-weighted spin-echo scans were most helpful in evaluating intradural tumors, whereas STIR sequences were most effective for extradural tumors and bone metastases. In most cases, Gd-DTPA-enhanced T1-weighted spin-echo scans best delineated tumor margins, and the enhancement was helpful in suggesting a cellular or active nature of the lesions. In some cases, the enhancement resulted in a more homogeneous and thus less abnormal-appearing marrow in vertebrae involved by tumor; therefore, a precontrast T1-weighted spin-echo scan is necessary in all patients who are to be studied with Gd-DTPA. A combined approach that uses T1-weighted spin-echo, Gd-DTPA-enhanced T1-weighted spin-echo, and STIR images currently appears optimal for MR imaging of spinal neoplasms. T2-weighted spin-echo images add information only in occasional cases.
Bone Marrow↗
Magnetic resonance imaging of soft tissue masses.
Twenty-nine soft tissue masses were studied with magnetic resonance imaging (MRI) which proved to be useful in the preoperative evaluation of these lesions. Other imaging modalities employed had significant limitations. Plain films were of little value because of the intrinsically low contrast of soft tissues. Angiography was not necessary unless MRI suggested a vascular lesion or proximity to major blood vessels. Computed tomography (CT) and MRI both readily identified fatty lesions and their relationship to adjacent structures. Some soft tissue tumors could not be delineated from normal muscle with CT, but were easily seen with MRI. MRI is ideally suited for the study of suspected soft tissue tumors because of its excellent soft tissue contrast and its ability to image directly in any plane. Optimum evaluation required imaging in at least two planes with spin echo sequences chosen to bring out both T1 and T2 features.
Adolescent↗
Classification and investigation of artifacts in magnetic resonance imaging.
Many MR artifacts are not understandable in terms of previous imaging experience. A variety of artifacts is presented here; their origins and elimination are discussed.
Diagnostic Imaging↗
Magnetic resonance imaging of bone marrow in hairy cell leukemia: correlation with clinical response to alpha-interferon.
Five patients with progressive hairy cell leukemia were treated with recombinant alpha 2-interferon and examined prospectively at 3-month intervals using serial bone marrow biopsies and magnetic resonance (MR) imaging. Pretreatment iliac crest marrow biopsies demonstrated hairy cell infiltration involving 30-90% of marrow cellularity. Concurrent pretreatment coronal images of the proximal femurs and pelvis using MR revealed extensive marrow involvement that varied in distribution from patchy to diffuse. At 6 months, all patients had responded to alpha 2-interferon with improvement in peripheral blood counts and decrease in lymphoid infiltration on marrow biopsy to 15-40%. Six-month follow-up MR scans demonstrated decreasing marrow leukemia infiltration and increasing marrow fat. MR bone marrow imaging appears useful in the initial diagnosis of hairy cell leukemia, for monitoring the response to treatment, and possibly for predicting relapse.
Bone Marrow↗
Magnetic resonance imaging of the bone marrow in patients with leukemia, aplastic anemia, and lymphoma.
Magnetic resonance imaging (MRI) of the bone marrow was performed in 29 patients with leukemia, aplastic anemia, or lymphoma who were scheduled for bone marrow transplantation, and in 12 normals. T1-weighted coronal images (TR600/TE40) of the pelvis and proximal femurs demonstrated marrow pathology in adult patients. A simple MR grading system was developed to classify patterns of marrow involvement, and MR grading of cellularity was correlated with marrow histology. Normal marrow produced a relatively high signal intensity reflecting the predominance of short T1 fat in the marrow space. MRI of pretransplant patients with chronic myelogenous leukemia and acute leukemia in relapse demonstrated a markedly decreased marrow signal, consistent with the replacement of marrow fat by longer T1 neoplastic tissues. Aplastic anemia could not be differentiated from normal with the pulse sequences employed. Marrow involvement by Hodgkin's lymphoma was detected as diffuse marrow infiltration with superimposed focal areas of even lower signal intensity, reflecting the nodular nature of Hodgkin's. These results indicate that infiltrative marrow disorders can be sensitively detected by MRI.
Adolescent↗
MR imaging of hemorrhagic adnexal masses.
Magnetic resonance (MR) imaging, performed on 31 women with 40 surgically proven adnexal masses, was reviewed to determine whether MR can distinguish hemorrhagic from nonhemorrhagic masses. Fourteen masses proved to be hemorrhagic at surgery including functional ovarian cysts (seven cases), cystadenoma (one case), endometriomas (three cases), hematosalpinx (one case), ectopic pregnancy (one case), and parametrial extension from cervical carcinoma (one case). A high signal intensity (compared with adjacent pelvic fat) on a T1-weighted spin echo sequence was found to be a reliable indicator of hemorrhage and was demonstrated in all 14 hemorrhagic masses. The "hematocrit" effect was seen as an area of high signal intensity layering in the dependent portion of six hemorrhagic cysts. Only four of 26 nonhemorrhagic masses demonstrated high signal intensity on T1-weighted sequences and, of these, three proved to be fat-containing dermoid cysts and one was a simple cyst with adherent mesenteric fat. We conclude that high signal intensity on a T1-weighted spin echo pulse sequence is evidence for a hemorrhagic mass and that a hematocrit effect appears to be a specific sign for a hemorrhagic cyst. The clinical significance of hemorrhagic adnexal masses is discussed.
Adnexal Diseases↗
Early diagnosis of spinal metastases by CT and MR studies.
Fifteen patients with known metastatic or high-risk primary cancer, normal neurologic examinations, and new abnormalities on 99mTc bone scan were evaluated with spinal CT and magnetic resonance (MR) imaging. Four patients underwent CT metrizamide myelography. Spinal CT and MR agreed in 14 of 15 patients demonstrating spinal metastases in 12 patients and benign disease in two. In one patient spinal CT was normal, but MR showed altered marrow signal consistent with metastatic disease. Epidural tumor was demonstrated by CT metrizamide myelography in four cases, all correctly identified by MR. Further evaluation of spinal MR in this setting is warranted.
Adult↗