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PURPOSE: To determine the efficacy of various magnetic resonance (MR) imaging sequences for the differentiation of adrenal masses. MATERIALS AND METHODS: Fifty-three adrenal masses in 46 patients (adenomas, metastases, myelolipomas, hemorrhages, and pheochromocytomas) were evaluated by means of T1-, T2-, and T2*-weighted sequences, calculated T2 values, chemical shift imaging techniques, and dynamic contrast material-enhanced imaging. The Student t test and receiver operating characteristic analysis were used to evaluate the differences in the groups of masses. RESULTS: Analysis of the chemical shift-induced signal intensity of the adrenal masses and the T2*-weighted sequence enabled differentiation of adenomas, metastases, and pheochromocytomas. Adenomas and pheochromocytomas were also differentiated by means of a heavily T2-weighted sequence. Signal intensity values for all masses overlapped. CONCLUSION: Although a chemical shift imaging technique and a T2*-weighted sequence helped correctly differentiate among the groups of adrenal masses, the degree of overlap suggests that it is still difficult to evaluate disease in individual patients.

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Intrameniscal degenerative changes, presumably due to mild repetitive trauma, have been shown in many college and professional athletes, but it is uncertain over what period of time they can develop or significantly progress. To ascertain this period, the authors used magnetic resonance (MR) imaging to examine one knee in each of 20 players in the starting lineup of a major college football team before and after the season. Only asymptomatic knees (right, n = 10; left, n = 10) were examined; the images were reviewed blindly by one experienced observer without reference to the other examination. A significant progression existed in the grade of signal intensity shown in the menisci over the course of the season (P less than .001). Although this is a small study covering only 1 year, these preliminary results suggest that significant degeneration can occur in the menisci of asymptomatic players over a single season.

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The evaluation of mammographic interpretations is a difficult challenge for a professional quality assessment program. As most images are read by a single observer and pathologic proof is obtained only if prompted by the report or if clinical symptoms warrant surgical intervention, it is difficult to construct a meaningful quality assessment program. The authors designed a program on the basis of a mammographic coding system that allows both individual physicians and practice groups to be evaluated. The program examines mammographic reports to determine the consistency of reporting by each physician and by the entire group. In addition, the program facilitated periodic evaluation of physicians with use of test cases. The coding system provided an easy method of correlating the mammographic reports with pathology reports from biopsy specimens, allowing a more thorough examination of possible systematic errors in the evaluation of the examinations, as well as enabling calculation of the positive predictive value for the diagnosis of cancer. The professional quality assessment program can be easily implemented in a busy clinical setting to evaluate whether mammograms were read consistently and "correctly" and to provide a method of continuing education for the physicians.

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Nineteen patients with known liver metastases were examined with two magnetic resonance (MR) pulse sequences at 0.5 T and three pulse sequences at 1.5 T. In addition, the patients were studied with computed tomography (CT) enhanced with ethiodized oil emulsion-13 (EOE-13). At 0.5 T a spin-echo (SE) 300/22 (repetition time/echo time, msec) sequence prospectively demonstrated 92.4% of the detectable liver metastases, while an SE 2,000/80 sequence showed 52.1% of the lesions. At 1.5 T, an SE 300/25 sequence depicted 68.3% and an SE 2,000/80 sequence 71.6%, while the more T1-weighted inversion recovery (IR) 2,000/600 (repetition time/inversion time, msec) sequence demonstrated 89.5% of the lesions. EOE-13 CT scans depicted 93.3%. These findings suggest that T1-weighted imaging is as successful at demonstrating liver metastases at 1.5 T with an IR 2,000/600 sequence as at 0.5 T with an SE 300/22 sequence. At both field strengths, MR imaging of the liver is comparable to state-of-the-art CT.

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Inversion recovery (IR), commonly considered a pulse sequence capable of producing T1-weighted images with excellent display of normal anatomy, is versatile: The null point and peak time provide a useful, succinct summary of the properties of IR and its capacity for producing both T1- and T2-weighted images. Shortening of the inversion time (TI) and creation of a short-TI inversion-recovery (STIR) pulse sequence increases sensitivity to malignancy and other abnormalities by making the effects of prolonged T1 and T2 on signal intensity additive and by nulling the signal from fat. The authors examined over 300 patients with various malignancies and compared STIR images with T1- and T2-weighted images obtained at 0.5 T. In 43 cases, signal-difference-to-noise ratios (SD/Ns) were calculated between tumor, fat, and muscle. In general, STIR images demonstrated tumor as a conspicuously high-intensity area in a background of muted, discernible anatomic detail. The good contrast achieved with STIR sequences between tumor and fat (SD/N = 18.1) and tumor and muscle (SD/N = 12.9) consolidated into a single image the information contained separately on T1- and T2-weighted images, which facilitates efficient detection and localization of malignancy.

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The lumbar spine magnetic resonance (MR) studies in 246 consecutive patients who suffered from persistent back and leg pain were evaluated for the degree of degenerative disc disease and the presence of disc bulging, prolapse, or herniation. No patient had a history of previous back surgery. In those patients, degenerative disc changes increased with age until the fifth decade of life, after which a relatively similar proportion of patients had degenerative disc disease. Significant dehydration and degeneration occurred in less than 5% of the upper two disc spaces while L4/5 and L5/S1 had marked changes in greater than 20%. Prolapse and herniation progressively increased with each lower interspace, where at L5/S1 it was present in nearly one-third of the patients. Although a few patients had disc prolapse or herniation with a nondegenerated disc, there was a relationship between the presence of disc degeneration and prolapse or herniation.

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Eighty-one adrenal masses in 68 patients were examined with magnetic resonance imaging (MRI). Masses included nonfunctioning adenomas (17), metastases (25), adrenocortical carcinomas (10), and pheochromocytomas (23). T1-weighted pulse sequences depicted the anatomy with a resolution comparable to that of computed tomography (CT). T2-weighted pulse sequences provided some histologic specificity separating nonfunctioning adenomas with low signal-intensity from metastases with intermediate signal-intensity and pheochromocytomas with high signal-intensity. Pheochromocytomas could always be distinguished from other adrenal masses. In 20% of the cases, metastases with low signal-intensity could not be distinguished from nonfunctioning adenomas.

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Twenty patients with known liver metastases were evaluated by unenhanced computed tomography (CT), scans enhanced with ethiodized oil emulsion-13 (EOE-13), and magnetic resonance (MR) imaging with three pulse sequences. Spin-echo (SE) 300/26 (repetition time/echo time, in msec) images prospectively demonstrated 95.4% of the detectable liver metastases; inversion recovery (IR) 1,500/100 (repetition time/inversion time, in msec) images revealed 90.8%; and EOE-13-enhanced CT scans showed 87.1%. SE 2,000/80 images showed 51.4%, and unenhanced CT scans 49.6%, of the metastases. The relationship of vascular anatomy to metastatic foci was best seen on SE 300/26 images and EOE-CT scans. SE 300/26, IR 1,500/100, and EOE-CT studies particularly improved detection of lesions in the 1-2-cm range compared with SE 2,000/80 imaging or unenhanced CT scanning. SE 300/26 and IR 1,500/100 sequences appear comparable to EOE-CT scans in demonstrating liver metastases and significantly superior to conventional CT scans. Because EOE-13 is generally not available, these MR sequences should be the procedure of choice for the diagnosis of liver metastases.

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Ultrasonographic (US) examinations of the upper abdomen were performed in 80 patients with Gaucher disease. Of the 49 patients that had not undergone splenectomy, 47 had splenic enlargement. Sixteen patients had multiple lesions in the spleen. Most patients had discrete hypoechoic lesions that corresponded pathologically to focal homogeneous clusters of Gaucher cells. Several patients had similar lesions that were hyperechoic and were composed of Gaucher cells and fibrosis or infarction. A few patients had a geographic pattern of irregular areas of involvement of Gaucher cells among normal splenic parenchyma. The liver was often enlarged but otherwise sonographically unremarkable. Patients with Gaucher disease often have US examinations of the left upper quadrant for abdominal pain. A variety of US findings in the spleen typical for Gaucher disease should be recognized and not interpreted as acute changes.

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The histologic type of adrenal tumors can be accurately predicted by MRI on the basis of their signal intensity on a T2-weighted image. However, a small but significant number of nonfunctioning adenomas, carcinomas, and metastases cannot be differentiated because they have similar signal intensities on a spin-echo 2500/80 scan. Eight (21%) of 38 of these tumors fell into this group. Differentiation between incidental adenomas and metastases can be conclusively achieved only when the primary neoplasm can also be imaged and displays high signal intensity on T2-weighted images.

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Magnetic resonance imaging (MRI) and angiography were compared in a prospective and blinded fashion in 10 consecutive patients with Takayasu's arteritis to evaluate the ability of MRI to detect vascular abnormalities in the large arteries of the thorax and abdomen. Only the aorta and its major branches were studied. MRI was performed with a 0.5-T superconducting instrument and a body coil. Overlapping cuts, oblique views, and cardiac gating were used. Using angiography as the gold standard, MRI correctly identified all lesions in three patients, gave false-positive findings in two patients, and gave false-negative findings in five patients. In the latter five patients, MRI missed areas of major pathology in proximal arch vessels. MRI sensitivity was only 38% with a patient-by-patient analysis and 54% with a lesion-by-lesion analysis. The visualization of specific arteries with MRI was compared to visualization with angiography, and was markedly inferior in all vessels except the aorta, the innominate artery, and the common iliac arteries. It appears that with current equipment and technology, MRI is inadequate as a screening examination or for detailed evaluation of arterial disease other than the aorta except in highly selected cases.

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Magnetic resonance imaging (MRI) of the adrenals was performed on 50 subjects: 5 normal volunteers, 6 Cushing patients with bilateral adrenal hyperplasia, 14 patients with adrenal adenomas, 3 with adrenal carcinomas, 15 with pheochromocytomas and 7 with metastatic disease to the adrenal. The normal and hyperplastic adrenal glands were imaged in all cases. Using the signal intensity of the adrenals on a T2 weighted image, various forms of adrenal pathology could be differentiated. A ratio of signal intensity of the adrenal mass to the liver was utilized and allowed the differentiation of adrenal adenomas from adrenal carcinomas, pheochromocytomas and metastases. Using the same ratio, metastases could be distinguished from pheochromocytomas as well. MRI appears to be particularly valuable in distinguishing clinically silent adrenal metastases from nonfunctioning adrenal adenomas.

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Twelve patients with fibrodysplasia ossificans progressiva were studied with computed tomography (CT). Characteristic swelling of the muscular fascial planes could be identified on CT scans prior to the development of ectopic ossification. Ossification could be seen on CT scans before it was apparent on plain radiographs. The pattern of ossification was similar to that seen at pathologic study, with multifocal sites developing adjacent to and extending around muscles. The appearance on CT scans confirms the hypothesis that the initial focus in fibrodysplasia ossificans progressiva is in the connective tissue.

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Magnetic resonance imaging was performed in 30 patients with adrenal masses. The abnormalities included adrenal adenomas (n = 10), carcinomas (n = 2), pheochromocytomas (n = 12), and adrenal metastases (n = 6). By the ratio of the signal intensity of the adrenal mass to that of the liver, adenomas could be distinguished from adrenal metastases, adrenal carcinomas, and pheochromocytomas. Metastases and pheochromocytomas could generally be differentiated.

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The extensive heterotopic bone formation in patients with fibrodysplasia ossificans progressiva (FOP) has been documented previously with radiographs. A case in which a Tc-99m MDP bone scan showed increased uptake at sites well before ossification could be documented radiographically is described. This finding suggests that bone scans would likely be useful to monitor the extent of involvement with FOP and to detect areas of new activity.

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