Biomedical subjects
Publications and source records attributed to M P Recht.
Recent advances in the treatment of articular cartilage abnormalities have created a need for an accurate noninvasive imaging method for the evaluation of articular cartilage. Although its role remains undefined in this regard, magnetic resonance imaging (MRI) appears to be the most promising method. We review the current status and possible future directions of MRI of articular cartilage.
Isolated or dominant osteolytic lesions of the patella are an unusual manifestation of gout. We present seven patients who had such patellar lesions unilaterally (six patients) or bilaterally (one patient) and analyze the radiologic characteristics to determine whether they can be differentiated from those of other osteolytic lesions of the patella. The lesions were uniformly characterized by a geographic pattern of bone destruction in the superolateral aspect of the patella. Five lesions were each accompanied by a peripatellar soft tissue mass, four of which contained calcification. It therefore appears that an osteolytic lesion of the superolateral portion of the patella, especially when associated with a peripatellar calcified soft tissue mass, should alert one to the possible diagnosis of gout. Awareness of this possibility may obviate the need for invasive diagnostic procedures.
Intra-articular ganglion cysts arising from the cruciate ligaments are unusual lesions, there being only nine previously reported cases. We report 16 cases and describe their MR appearance. Nine ganglia originated from the posterior cruciate ligament, most often appearing as well-defined multilocular lesions. The seven ganglia arising from the anterior cruciate ligament most often appeared as fusiform cystic lesions extending along and interspersed within the fibers of the ligament. Although uncommon, intra-articular ganglion cysts arising from the knee appear to have a distinctive MR appearance which should allow their correct diagnosis.
Advances in surgical and pharmacologic techniques for treating and preventing chondral abnormalities are creating a demand for an accurate, noninvasive imaging method to evaluate articular cartilage. The most promising technique is MR imaging, but its exact role in this evaluation remains undefined. This article reviews the MR appearance of normal and abnormal articular cartilage and the various pulse sequences that can be used to evaluate chondral lesions. It also briefly discusses possible future directions for MR imaging of articular cartilage.
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In an attempt to improve the detection of chondral abnormalities with magnetic resonance imaging, a fat-suppressed three-dimensional gradient-recalled acquisition in the steady state (GRASS) and spoiled GRASS (SPGR) sequence was optimized by study of five cadaveric knee specimens. Results with this optimized sequence then were compared with results with three spin-echo (T1-, proton-density-, and T2-weighted) and two three-dimensional gradient-recalled echo sequences (GRASS and non-fat-suppressed SPGR) in the assessment of naturally occurring abnormalities of the patellofemoral compartment in 10 cadaveric knees. Results with the optimized fat-suppressed SPGR sequence were significantly better (P < .02) than results with the other five sequences and had a sensitivity of 96%, a specificity of 95%, and an accuracy of 95%. In addition, normal cartilage consistently appeared as a trilaminar structure with the fat-suppressed SPGR sequence, a feature that appeared to help in identification of chondral lesions.
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Ten of 27 patients (37%) with scleroderma who underwent endoscopy at our hospital between 1980 and 1984 for symptoms of reflux esophagitis had biopsy-proven Barrett's esophagus. Two of those 10 patients had esophageal adenocarcinomas. In a blinded review of esophagrams (all but 2 using double-contrast technique) from 16 of the 27 patients, only 1 patient was thought to be at high risk for Barrett's esophagus due to a high esophageal stricture with an adjacent reticular pattern of the mucosa. The latter patient had biopsy-proven Barrett's mucosa. Eight patients were thought to be at moderate risk for Barrett's esophagus due to reflux esophagitis and/or distal strictures in 6 and polypoid intraluminal masses in 2. Three of the 6 patients with esophagitis and/or strictures had Barrett's esophagus, and both patients with masses had adenocarcinomas arising in Barrett's mucosa. Finally, 7 patients who had no esophagitis or strictures were thought to be at low risk for Barrett's esophagus. None of those 7 had histologic evidence of Barrett's mucosa. Thus, the major value of double-contrast esophagography is its ability to classify patients into high-, moderate-, and low-risk for Barrett's esophagus to determine the relative need for endoscopy and biopsy in these patients.
Traumatic injuries are a major cause of hand and wrist pain in athletes. Wrist injuries include fractures, dislocations, and instability patterns. Hand injuries include tendon injuries, ligamentous injuries, and fractures. In this article we have presented the radiographic appearance of the more common of these injuries.
A wide spectrum of osseous abnormalities has been reported in association with vascular lesions. Enchondromas, bone hypertrophy, bone lysis, and sclerotic bone lesions have all been reported in association with hemangiomas, lymphangiomas, varicosities, and arteriovenous fistulae. These associations can be grouped into four major syndromes: Maffucci syndrome, mixed sclerosing bone dystrophy with angiodysplasia, congenital angiectatic hypertrophy (Klippel-Trenaunay-Weber syndrome), and massive osteolysis (Gorham syndrome).
Although magnetic resonance (MR) images of the glenohumeral joint frequently demonstrate intraarticular fluid, no specific criteria have, to the authors' knowledge, been published that allow accurate assessment of the amount of fluid present. Also, despite the increasing use of MR arthrography of the shoulder, the optimal amount of intraarticular fluid that should be used with this technique has not been determined. The authors progressively distended the glenohumeral joint in six cadaveric shoulder specimens with a dilute gadopentetate dimeglumine solution and obtained MR images after injection of 2, 5, 10, 15, and 20 mL of the solution. The pattern of fluid distribution was evaluated, and these results were then used to estimate the amount of fluid that was present in the glenohumeral joint on MR images of 20 shoulders obtained in 12 asymptomatic volunteers. In 14 of these shoulders, intraarticular fluid was present; however, in none was more than 2 mL evident. Results of the cadaveric study also indicated that 15 mL of intraarticular fluid appears to be the optimal amount for MR arthrography.
Three-dimensional (3D) MR imaging of the knee is useful to detect cartilage abnormalities, although the tissue contrast in 3D gradient-recalled echo (GRE) sequences such as gradient-recalled acquisition in the steady state (GRASS) or fast low-angle shot (FLASH) is poor. T2 contrast can be added to a GRASS sequence by combining the signals from the first and second gradient echoes, which form immediately after and immediately before each radio frequency (RF) pulse in a 3D GRE sequence. We have optimized a 3D dual echo in the steady state (DESS) sequence, which produces one averaged image from the two echoes, for use in the detection of articular cartilage abnormalities. In the optimization process, we examined the imaging parameters of flip angle (alpha), repetition time (TR), echo time (TE), and bandwidth to maximize the contrast between cartilage and joint fluid. A theoretical simulation of the sequence was confirmed with experiments conducted on phantoms with known T1 and T2. On the basis of theoretical predictions and experiments using healthy volunteers, we determined that an optimized sequence with a bandwidth of 98 Hz per pixel, TR of 30 msec, a TE of 7.1 msec, and an alpha of 60 degrees produced the highest contrast between cartilage and fluid within a defined acquisition time of 6 minutes. Additional contrast was obtained by filtering the second-echo image to eliminate noise before adding it to the first-echo image.
We developed a three-dimensional, gradient-recalled-echo imaging technique that incorporates a short-duration spatial-spectral excitation pulse from the family of binomial pulses. Binomial pulses of different orders were tested on phantoms and on normal volunteers to find the composite pulse that produced in the shortest duration the most reliable fat suppression. Composite pulses employing unipolar slice-selective gradients with explicit rewinder gradients between each radio-frequency (RF) pulse were compared with composite RF pulses employing alternating-polarity, slice-select gradients. The advantage of the sequences using the unipolar gradients is improved fat suppression. Images of the knees of volunteers produced with the composite RF pulse have contrast between fat and articular cartilage equivalent to that on images created by the gradient-recalled-echo imaging technique employing a conventional chemsat pulse. The optimum RF pulse consisted of three amplitude- and phase-modulated pulses combined with unipolar slice-select gradients.
Three cases of surgical implantation of esophageal carcinoma during esophagogastrectomy are presented. The CT and radiographic appearance is demonstrated. A possible etiology and method for decreasing the risk of surgical spread of tumor are discussed.
The authors compared six MR sequences comprising conventional breath-hold [rapid spin echo (RASE) repetition time (TR) 240 ms/echo time (TE) 8 ms/90 degrees, fast low angle shot (FLASH) 130/4.5/80 degrees, TurboFLASH 6.5/3.5/8 degrees], fat suppressed regular spin echo (FS SE 330/15/90 degrees), and two combined fat suppressed breath-hold sequences (FS FLASH 130/8/80 degrees, FS RASE 240/10/90 degrees) for studying the normal pancreas. Sequences were selected on the basis of features desirable for demonstrating the pancreas, particularly absence or decrease in artifacts and improved dynamic range of intraabdominal tissue signal intensities. Ten normal volunteers were studied, six at 1.5 T and four at 1.0 T, and comparison was made to regular short TR/TE SE. Quantitative pancreas signal-to-noise (S/N) and pancreas fat-to-noise (SD/N) measurements and qualitative evaluation of overall resolution and artifacts were determined. Fat suppressed FLASH had the highest S/N (44.1 +/- 10.8, p less than 0.0001) and SD/N (35.0 +/- 11.9, p less than 0.0001), and seven studies were considered good or very good. Fat suppressed SE had good S/N (32.6 +/- 7.7) and SD/N (19.0 +/- 3.6), and eight FS SE studies were considered good or very good. Among the nonsuppressed sequences, FLASH had the best combination of quantitative and qualitative measurements. Our results suggest that fat suppression may be important for studying the pancreas and that nonsuppressed FLASH may be a reasonable alternative.
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OBJECTIVE: Although MR has been proven effective in evaluating many components of the musculoskeletal system, including ligaments, fibrocartilage, muscle, and bone marrow, its role in the evaluation of articular cartilage remains controversial. Recent studies have demonstrated that intraarticular injection of Gd-DTPA [MR arthrography (MRA)] improves the detection of cartilage abnormalities in cadaveric specimens. The aim of this study was to determine the efficacy of MRA for the detection of naturally occurring cartilage lesions in a clinical population. MATERIALS AND METHODS: Sixty knees of 58 patients were studied with a three-dimensional (3D) T2*-weighted GE sequence (FISP) both before and after and a T1-weighted (T1W) SE sequence after the intraarticular injection of a 2 mmol/L Gd-DTPA solution. All knees subsequently underwent arthroscopy or arthrotomy. RESULTS: The MRA sequences performed significantly better (kappa = 0.85) than the routine FISP sequences (kappa = 0.39) in both the detection and the staging of cartilage abnormalities. The MRA FISP sequence (kappa = 0.91) performed slightly better than the MRA T1W sequence (kappa = 0.85), but there was no statistically significant difference between the two sequences. No complications from the intraarticular injection of contrast material occurred. CONCLUSION: Therefore, MRA appears to be an effective and safe method for the evaluation of articular cartilage abnormalities.