Abstract: The authors reviewed magnetic resonance (MR) images of 474 consecutive patients referred for lumbar spine MR imaging. Type 1 changes (decreased signal intensity on T1-weighted spin-echo images and increased signal intensity on T2-weighted images) were identified in 20 patients (4%) and type 2 (increased signal intensity on T1-weighted images and isointense or slightly increased signal intensity on T2-weighted images) in 77 patients (16%). In all cases there was evidence of associated degenerative disk disease at the level of involvement. Histopathologic sections in three cases of type 1 change demonstrated disruption and fissuring of the end plates and vascularized fibrous tissue, while in three cases of type 2 change they demonstrated yellow marrow replacement. In addition, 16 patients with end-plate changes documented with MR were studied longitudinally. Type 1 changes in five of six patients converted to a type 2 pattern in 14 months to 3 years. Type 2 changes in ten patients remained stable over a 2-3...

Abstract: Specified regions of the myocardium can be labeled in magnetic resonance (MR) imaging to serve as markers during contraction. The technique is based on locally perturbing the magnetization of the myocardium with selective radio-frequency (RF) saturation of multiple, thin tag planes during diastole followed by conventional, orthogonal-plane imaging during systole. The technique was implemented on a 0.38-T imager and tested on phantoms and volunteers. In humans, tags could be seen 60-450 msec after RF saturation, thus permitting sampling of the entire contractile phase of the cardiac cycle. Tagged regions appear as hypointense stripes, and their patterns of displacement reflect intervening cardiac motion. In addition to simple translation and rotation, complex motions such as cardiac twist can be demonstrated. The effects of RF pulse angle, relaxation times, and heart rate on depiction of the tagged region are discussed.

Abstract: The pattern of normal white-matter maturation as demonstrated with high-field-strength magnetic resonance (MR) imaging was investigated. Eighty-two neurologically normal infants were examined with a 1.5-T unit with use of spin-echo T1-weighted and T2-weighted pulse sequences. The infants ranged in age from 4 days to 2 years. The images were assessed for qualitative changes of white matter relative to gray matter in 14 anatomic areas of the brain and correlated with the patient's age. The MR images showed that changes of brain maturation occur in an orderly manner, commencing in the brain stem and progressing to the cerebellum and the cerebrum. Changes caused by brain myelination were seen earlier on T1-weighted images than on T2-weighted images, possibly because of T1 shortening by the components of the developing myelin sheaths. The later changes on the T2-weighted images correlated best with the development of myelination as demonstrated with histochemical methods. T1-weighted images were most useful in the monitoring of normal brain development in the first 6-8 months of life; T2-weighted images were more useful after 6 months. The milestones in the MR appearance of normal maturation of the brain are presented. Persistent areas of long T2 relaxation times are seen superior and dorsal to the ventricular trigone in all infants examined and should not be mistaken for ischemic change.

Abstract: La moelle normale, anatomie et fonction. Distribution de la moelle hematopoietique en fonction de l'âge, composition chimique. Les methodes d'imagerie: radiographie, scintigraphie TDM, RMN. Les images RMN dependent des sequences de pulsion. Choix des techniques. Pathologie. Greffes de moelle. Œdemes medullaires. Ischemies

Abstract: Of 293 patients who underwent computed tomography (CT), surgery, and pathologic examination for chronic sinusitis, 25 had a diagnosis of fungal sinusitis at pathologic examination. Of these, 22 had foci of increased attenuation at CT (in four patients the mean representative CT number [Hounsfied unit] was 122.2 HU [SD, 8.2 HU]), and three did not. Of the 22, 19 patients (76%) met the CT criterion of this study (there was a 12% false-positive and a 12% false-negative diagnostic rate). Six of the 19 patients and one additional patient underwent magnetic resonance (MR) imaging, and all demonstrated remarkably hypointense signal characteristics on T2-weighted images. The findings at MR imaging therefore appear more characteristic of fungal sinusitis than the findings at CT. Furnace atomic absorption spectrometry showed increased concentrations of iron and manganese in mycetoma compared with their concentrations in bacterially infected mucus. This finding and the presence of calcium in the fungal concretion ma...

Abstract: Ten patients with debilitating hip or knee pain were examined with magnetic resonance (MR) imaging. All had conventional radiographs that were either normal or showed nonspecific osteopenia. Nine patients had bone scintigrams that showed focal increased radionuclide uptake in the region of the painful joint. In each case, MR images of the affected joint showed regional decreased signal intensity of the bone marrow on T1-weighted images and increased signal intensity on T2-weighted images. Biopsy results of four patients excluded ischemic necrosis and metastases. The symptoms resolved spontaneously in all cases. The ten patients were followed up for 12-36 months, and there were no recurrences. The authors believe that the findings on MR images represent a transient increase in bone marrow water content. The focal findings on scintigrams confirmed the periarticular distribution of the process and provided evidence of accompanying hyperemia and increased bone mineral metabolism. For lack of a better term and to emphasize the generic character of the condition, the authors termed this condition "the transient marrow edema syndrome."

Abstract: To determine changes in bone density during growth, trabecular vertebral density and an index of spinal cortical bone were measured with quantitative computed tomography in 101 children The children were divided by age into three groups: prepubertal, indeterminate, and pubertal Compared with prepubertal children, pubertal adolescents had significantly higher trabecular bone density and more compact bone in the spine (P less than 001) After controlling for puberty, vertebral bone density failed to correlate significantly with age, sex, weight, height, surface area, and body mass index The results indicate that bone density increases markedly during puberty

Abstract: One of the major uses of quantitative computed tomography (CT) has been the measurement of bone mineral density (BMD) at various skeletal sites. The published literature on this subject from 1974 to the present is extensive. Because many investigators and clinicians are just now starting to explore the utility of this technique, the author reviewed this literature to provide both the historic perspective and current status of BMD measurement with CT. The physical and physiologic bases of the method, accuracy, reproducibility, radiation dose, and clinical utility are all discussed.

Abstract: The accuracy of magnetic resonance (MR) imaging in staging invasive carcinoma of the cervix was determined retrospectively in 57 consecutive patients in whom the extent of disease was surgically confirmed. MR images were analyzed for (a) location and size of the primary tumor; (b) tumor extension to the uterine corpus, vagina, parametria, pelvic sidewall, bladder, or rectum; and (c) pelvic lymphadenopathy. The accuracy of MR imaging in determination of tumor location was 91% and for determination of tumor size within 0.5 cm, 70%. Its accuracy was 93% for vaginal extension and 88% for parametrial extension. Pelvic sidewall, bladder, and rectal involvement were accurately excluded in all patients, but the positive predictive values were 75%, 67%, and 100%, respectively. Overall, the accuracy of MR imaging in staging was 81%. MR imaging is valuable because it can accurately demonstrate tumor location, tumor size, degree of stromal penetration, and lower uterine segment involvement. It is also valuable for ruling out parametrial, pelvic sidewall, bladder, and rectal involvement.

Abstract: High-resolution real-time ultrasonography (US) was used to evaluate peripheral nerves of the extremities in healthy subjects and in 11 patients with a mass developed from a peripheral nerve. The normal median and ulnar nerves in the upper extremity and the normal sciatic and external popliteal nerves in the lower extremity were seen, all having an echogenic fibrillar echotexture. Pathologic findings included nine cases of benign tumor (four schwannomas, three neurofibromas, two traumatic neuromas), one of neurilemmitis, and one of tuberculoid leprosy. All lesions were hypoechoic. Three of the four schwannomas had well-defined contours, and two were associated with a typical distal sound enhancement. Neurofibromas and traumatic neuromas were less sharply delineated. Inflammatory conditions were characterized by a hypoechoic, thickened nerve. US was effective in imaging nerve masses in the extremities, and large normal nerves can now be demonstrated with high-resolution US.

Abstract: The ventricular atria in 100 healthy fetuses with gestational ages ranging from 14 to 38 menstrual weeks were evaluated and compared with those of 38 fetuses in whom ventriculomegaly had been diagnosed in utero. Axial sonograms of the brain through the atrium of the lateral ventricle demonstrated that the normal atrial diameter remained relatively constant throughout the gestational age range observed. The atrium had a mean diameter of 7.6 +/- 0.6 mm (standard deviation [SD]). Measurement of this structure can be quickly performed, is reproducible with low intra- and interobserver variation, and permits ventriculomegaly to be excluded. Atrial diameters exceeding 10 mm (above 4 SDs) suggest ventriculomegaly, with a low false-positive rate.

Abstract: Seventy-nine magnetic resonance (MR) studies of the knee were reviewed in an evaluation of the ability of MR imaging to demonstrate arthroscopically proved anterior cruciate ligament (ACL) tears. MR findings were also compared with the findings of two commonly applied clinical tests of ACL instability: the Lachman test and the anterior drawer test. The sensitivity of MR imaging was 94% (17 of 18), compared with 78% (14 of 18) for the anterior drawer test and 89% (16 of 18) for the Lachman test. The specificity was 100% for all three. Three MR criteria were applied: irregularity or a wavy contour of the anterior margin of the ligament, high-signal-intensity change within the substance of the ligament on T2-weighted images, and discontinuity of that substance. The sagittal T2-weighted image was especially helpful, producing an "arthrographic" effect, in which the anterior margin of the ACL is outlined by high-signal-intensity joint fluid. By demonstrating ACL and other extrameniscal lesions, MR imaging may help clarify the mechanisms of knee injury.

Abstract: Computed tomography (CT) was used to guide percutaneous fine-needle biopsy in 150 cases of difficult thoracic lesions; in 76 cases, nondiagnostic bronchoscopy (n = 62) and fluoroscopic biopsy (n = 14) had previously been performed. CT was indicated for guidance when the pulmonary or pleural lesions were small (0.3-2.5 cm); in a juxta-vascular location, either hilar or mediastinal; not seen or poorly visualized on conventional radiographs; or considered inaccessible. A diagnosis was made in 124 of 150 cases (82.7%) (107 of 124 malignant and 17 of 26 benign lesions), including 86 of 107 lung nodules (80.4%), 28 of 31 mediastinal lesions (90.3%), and ten of 12 pleural masses (83.3%). Complications included pneumothorax (n = 64), hemoptysis (n = 5), hemothorax (n = 2), and pericarditis (n = 1). The high rate of pneumothorax, its treatment, and advantages of its immediate radiologic management are discussed. Use of CT guidance considerably expands the scope of thoracic lesions amenable to percutaneous biopsy.

Abstract: The authors assessed the accuracy of dynamic computed tomography (CT) in diagnosis and staging of ductal adenocarcinoma of the pancreas and analyzed the survival rates of patients with resectable and unresectable tumors. A correct diagnosis based on CT findings was made in 159 of 174 patients (91%) with 13 false-positive (8%) and two false-negative diagnoses (1%). The 13 false-positive diagnoses highlight the need for confirmation of diagnosis with biopsy. The accuracy of staging with CT was compared with that of angiography (42 patients) and surgery (51 patients). CT was more accurate than angiography in demonstrating tumor involvement of major peripancreatic vessels. Staging criteria were reliable: No unresectable tumors based on CT findings were found to be resectable during surgery (42 patients), while only three of nine resectable tumors based on CT findings were found to be unresectable. Thus, no tumors were incorrectly staged, which would potentially deny surgery for a patient. The average survival...

Abstract: Early computed tomographic (CT) findings (scans obtained within 6 hours of the onset of stroke) were retrospectively analyzed in 25 patients with embolic cerebral infarction of the middle cerebral artery or internal carotid artery distribution, including the lentiform nucleus, diagnosed on the basis of findings at sequential CT. CT scans were analyzed for the following: (a) an obscured outline or partial disappearance of the lentiform nucleus, (b) a slight decrease in tissue density, or (c) effacement of the cortical sulci. One or more of these findings was recognized in 23 of 25 patients (92%). The first finding was noted most frequently, and it appeared earliest. Obscuration of the lentiform nucleus was thought to be an important early sign of cerebral infarction, including the lentiform nucleus.

Abstract: The authors examined 784 self-referred men over age 60 years to compare clinical usefulness of transrectal ultrasound (US) and digital rectal examination in a screening program for prostate cancer. Biopsy was performed in 77 cases, 83% (64 of 77) for abnormalities detected with transrectal US and 38% (29 of 77) because of findings at digital examination. Twenty-two cancers were detected, 20 with transrectal US and ten at digital examination. Overall detection rate for prostate cancer with transrectal US was two times higher than that with digital examination (2.6% vs 1.3%). Sensitivity, specificity, and negative predictive value for transrectal US and digital examination were calculated for a range of prevalences (0.028-0.1543). Sensitivity was two times higher for transrectal US than for digital examination. Transrectal US demonstrated 100% (17 of 17) of tumors with the most favorable prognosis (less than or equal to 1.5 cm in diameter) compared with 41% (seven of 17) for digital examination. The authors conclude that transrectal US is more sensitive than digital examination in the detection of prostate cancer, and they advocate broader implementation and evaluation of transrectal US as a tool for early detection.

Abstract: The relaxivity, biodistribution, and toxicity of the gadolinium-tetraazacyclododecanetetraacetic acid (Gd-DOTA) complex were evaluated. This cyclic complex has much greater in vitro stability (10(28)) than similar noncyclic complexes such as gadolinium-diethylenetriaminepentaacetic acid (Gd-DTPA) (10(23)) or gadolinium-ethylenediaminetetraacetic acid (Gd-EDTA) (10(17)). The T1 relaxivity of Gd-DOTA (meglumine salt) determined in saline and in liver tissue at 20 MHz was similar to the relaxivity of Gd-DTPA. Tissue proton relaxation enhancement (PRE) correlated closely with chemical measurement of tissue gadolinium concentration. In rats, the biodistribution of Gd-DOTA was similar to Gd-DTPA with a distribution half-life of 3 minutes and an elimination half-life of 18 minutes. The median lethal dose (LD50) in mice of Gd-DOTA was 93% higher than that of Gd-DTPA; the calculated safety factor (ratio of LD50 to effective dose) was 53 for Gd-DOTA and 28 for Gd-DTPA. The data suggest that in vitro stability correlates with in vivo safety.

Abstract: Magnetic resonance (MR) images were retrospectively evaluated in eight patients who had recent, symptomatic knee injuries and in whom plain radiographs showed no fractures. T2-weighted images revealed irregular, intraosseous areas of high signal intensity; T1-weighted and proton density images revealed speckled or linear regions of low signal intensity in corresponding areas. In the seven patients whose injuries did not result from direct contusion, abnormalities occurred in subchondral locations. Two patients underwent bone scintigraphy, which showed increased activity in locations corresponding to areas of abnormality noted on MR images. Two patients underwent follow-up MR imaging at 6 weeks and 3 months, which showed complete resolution of the abnormalities. The authors speculate that the MR imaging findings represent microscopic compression fracture of trabecular bone and discuss the related entity, stress fracture.

Abstract: A thorough knowledge of the normal changes that occur in the brain with age is critical before abnormal findings are analyzed. Magnetic resonance (MR) imaging improves the ability to distinguish normal and abnormal findings in the brain. The major changes that may occur in elderly individuals without neurologic deficits include enlargement of the ventricles, cortical sulci, and vermian subarachnoid spaces; multifocal areas of hyperintensity in the white matter and basal ganglia; a progressive prominence of hypointensity on T2-weighted images of the putamen, almost equal to that of the globus pallidus; an increase in the oxygen extraction ratio with normal or mildly decreased neuron metabolism; arteriosclerosis in large and small arteries and amyloid angiopathy in leptomeningeal cortical vessels; and decreased dopamine receptor binding in the corpus striatum. Since approximately half of the elderly population exhibits only negligible brain alterations, MR imaging may facilitate the distinction between usua...

Abstract: Twenty-nine subjects with occupational asbestos exposure and clinical asbestosis were examined with high-resolution computed tomography (HRCT) to determine its sensitivity, relative to that of conventional computed tomography (CT), for detection of benign asbestos-related disease. Thin-section HRCT scans were obtained at five discrete levels through the mid and lower thorax in both prone and supine positions. The same technique was used in 34 age-similar control patients. Parenchymal abnormalities were seen most frequently in the posterior portion of the lung bases in the asbestos-exposed subjects. HRCT prone scans enabled basal structural abnormalities to be reliably distinguished from gravity-related physiologic phenomena in 25 asbestos-exposed subjects. HRCT was more sensitive than CT in detection of both pleural and parenchymal fibrosis. In subjects with clinical asbestosis, HRCT demonstrated parenchymal abnormality in 96%, compared with 83% for CT. Similarly, pleural thickening was shown in 100% of s...

Abstract: Focal and confluent areas of periventricular hyperintensity have been reported on magnetic resonance (MR) images in 30% of patients over 60 years of age. In order to better understand the pathologic basis of these lesions, the authors studied 14 formalin-fixed brains with MR imaging. Multiple focal areas of hyperintensity were identified in the periventricular white matter in three of the 14 brains studied (21%). Subsequent gross and microscopic pathologic examination of both hyperintense and normal-intensity areas was performed on 87 tissue sections. The larger lesions were characterized centrally by necrosis, axonal loss, and demyelination and therefore represent true infarcts. Reactive astrocytes oriented along the degenerated axons were identified at distances of up to several centimeters from the central infarct. This is called isomorphic gliosis and is associated with increased intensity on T2-weighted images that increases the apparent size of the central lesion.

Abstract: A prospective blinded study of 201 patients was performed to determine the relative sensitivities and specificities of excretory urography/linear tomography (EU/LT) and ultrasound (US) for the diagnosis of renal parenchymal masses. Computed tomography (CT) was used as a standard. EU/LT permitted detection of 10% of CT-confirmed masses (cystic or solid) less than 1 cm, 21% of lesions greater than or equal to 1 cm but less than 2 cm, 52% of lesions greater than or equal to 2 cm but less than 3 cm, and 85% of lesions 3 cm or more in diameter. US permitted detection of 26% of CT-confirmed lesions less than 1 cm, 60% of lesions greater than or equal to 1 cm but less than 2 cm, 82% of lesions greater than or equal to 2 cm but less than 3 cm, and 85% of lesions 3 cm or more in size. The results confirm the relative insensitivity of EU/LT for masses less than 3 cm in diameter and of US for masses less than 2 cm. Further, they suggest that CT may have a role not only in evaluation of cases in which the urographic or sonographic results are questionable or positive, but also in confirmation of apparently negative urographic findings when clinical suspicion of a lesion is high.

Abstract: Magnetic resonance imaging, computed tomographic, and positron emission tomographic studies of the brain provide complementary information, and many patients undergo more than one of these studies during the course of their diagnostic workup and treatment. A new technique for quantitative geometric correlation of such studies makes it possible to create integrated multimodality images by mapping features from one image onto an image obtained with another modality. The coordinate transformation between any pair of images is found by a semiautomatic algorithm for matching models of the patient's external surface as depicted in the two data sets. The resultant hybrid images, which combine complementary features of different studies, are often more useful for diagnosis and treatment planning than are the original single-modality images. The algorithm can also be used for spatial registration of baseline studies with follow-up images created with the same modality, which allows tracking of a lesion to detect s...

Abstract: Thirty patients with failed back surgery syndrome were studied to evaluate the effectiveness of magnetic resonance (MR) imaging with gadolinium-diethylenetriaminepentaacetic acid/dimeglumine (Gd-DTPA) in differentiating postoperative epidural fibrosis (scar) from recurrent disk herniation. Pre- and postcontrast MR images were interpreted without access to other diagnostic, surgical, or pathologic findings. Seventeen patients had surgical and pathologic correlation of the MR findings at 19 disk levels. The precontrast studies had a sensitivity, specificity, and accuracy of 100%, 71%, and 89%, respectively. The enhanced MR studies correctly depicted the character of abnormal epidural soft tissue in 17 patients at all 19 levels. Scar showed heterogeneous enhancement on the early T1-weighted spin-echo images obtained within 10 minutes after contrast material administration. Herniated disk did not show significant enhancement on the early studies but showed variable degrees of enhancement on delayed images in ...

Abstract: The magnetic resonance (MR) and computed tomographic (CT) images of 53 patients with sinonasal tumors were analyzed and compared for accuracy in tumor mapping. the findings were confirmed by means of either surgery or biopsy. The MR images of 60 patients with inflammatory disease were also studied, and the findings were confirmed at surgery. Forty-seven additional MR images were also examined of patients with tumors showing histologic characteristics similar to those found in the sinonasal tumor group but occurring elsewhere in the head and neck, excluding the orbit. This study concludes that nearly 95% of sinonasal tumors have an intermediate T2 signal, while only 5% have bright T2 signals. This small latter group is composed almost exclusively of some minor salivary gland tumors and some neuromas. The inflammatory tissues all had bright T2 signals. The distinction between sinonasal tumors and inflammatory tissues was best accomplished with T2-weighted studies, and MR imaging was more accurate than CT.

Abstract: The accuracy of coronal and sagittal magnetic resonance (MR) imaging was examined in the assessment of rotational and sideways displacements of the temporomandibular joint (TMJ) disk Rotational disk displacement implies a combination of anterior and medial or lateral displacements, whereas sideways displacement implies pure medial or lateral displacement without an anterior component Multiple 3-mm-thick coronal and sagittal MR images were obtained of 18 fresh TMJ autopsy specimens and compared with the observations in corresponding coronal cryosections MR imaging correctly delineated the mediolateral position of the disk in 15 joints (83%) and incorrectly delineated it in three joints (17%) Osseous anatomy was correctly assessed in 17 joints (94%) On cryosections, six joints (33%) showed medial disk displacement and two joints (11%) showed lateral displacement In five of these eight joints the medial or lateral displacement occurred in conjunction with an anterior displacement, that is, rotational displacement Clinical MR imaging in 37 patients (61 joints with coronal images) showed medial or lateral disk displacement in 16 joints (26%) This study suggests that rotational and sideways displacements of the TMJ disk are an important aspect of internal derangement The multiplanar capabilities of MR are suitable for an assessment of these abnormalities

Abstract: The clinical, radiologic, and neuropathologic findings in 13 patients with central pontine myelinolysis were reviewed. Antemortem computed tomography (CT) had been performed in nine, and ante- or postmortem magnetic resonance (MR) imaging in 11. Chronic alcoholism or rapid correction of hyponatremia was present in over 75% of cases. One CT scan was positive, but only on retrospective review. In all but one patient, MR imaging eventually revealed an abnormality within the pons; in two patients the initial study was normal. The lesions varied in shape, with peripheral involvement in two patients and extrapontine involvement in four. The abnormality was smaller at 6-month follow-up in one patient and unchanged at 1 year in another. One patient never had a demonstrable pontine lesion but did have symmetric basal ganglia abnormalities, which were consistent with extrapontine myelinolysis. MR imaging disclosed similar central pontine alterations resulting from infarct, metastasis, glioma, multiple sclerosis, encephalitis, and radiation or chemotherapy; thus, such changes are not unique.