Detection of cartilage damage in femoroacetabular impingement with standardized dGEMRIC at 3 T

OBJECTIVE

This study aimed at identifying the optimal threshold value to detect cartilage lesions with Standardized delayed Gadolinium-Enhanced MRI of Cartilage (dGEMRIC) at 3 T and evaluate intra- and inter-observer repeatability.

DESIGN

We retrospectively reviewed 20 hips in 20 patients. dGEMRIC maps were acquired at 3 T along radial imaging planes of the hip and standardized to remove the effects of patient's age, sex and diffusion of gadolinium contrast. Two observers separately evaluated 84 Standardized dGEMRIC maps, both by visual inspection and using an average index for a region of interest (ROI) in the acetabular cartilage. A radiologist evaluated the acetabular cartilage on morphologic MR images at exactly the same locations. Using intra-operative findings as reference, the optimal threshold to detect cartilage lesions with Standardized dGEMRIC was assessed and results were compared with the diagnostic performance of morphologic magnetic resonance imaging (MRI).

RESULTS

Using z < -2 as threshold and visual inspection of the color-adjusted maps, sensitivity, specificity and accuracy for Observer 1 and Observer 2, were 83%, 60% and 75%, and 69%, 70% and 69%, respectively. Overall performance was 52%, 67% and 58%, when using an average z for the acetabular cartilage, compared to 37%, 90% and 56% for morphologic assessment. The kappa coefficient was 0.76 and 0.68 for intra- and inter-observer repeatability, respectively, indicating substantial agreement.

CONCLUSIONS

Standardized dGEMRIC at 3 T is accurate in detecting cartilage damage and could improve preoperative assessment in femoroacetabular impingement (FAI). As cartilage lesions in FAI are localized, visual inspection of the Standardized dGEMRIC maps is more accurate than an average z for the acetabular cartilage.

Micro-finite element analysis applied to high-resolution MRI reveals improved bone mechanical competence in the distal femur of female pre-professional dancers

Micro-finite element analysis applied to high-resolution (0.234-mm length scale) MRI reveals greater whole and cancellous bone stiffness, but not greater cortical bone stiffness, in the distal femur of female dancers compared to controls. Greater whole bone stiffness appears to be mediated by cancellous, rather than cortical bone adaptation.

INTRODUCTION

The purpose of this study was to compare bone mechanical competence (stiffness) in the distal femur of female dancers compared to healthy, relatively inactive female controls.

METHODS

This study had institutional review board approval. We recruited nine female modern dancers (25.7±5.8 years, 1.63±0.06 m, 57.1±4.6 kg) and ten relatively inactive, healthy female controls matched for age, height, and weight (32.1±4.8 years, 1.6±0.04 m, 55.8±5.9 kg). We scanned the distal femur using a 7-T MRI scanner and a three-dimensional fast low-angle shot sequence (TR/TE=31 ms/5.1 ms, 0.234 mm×0.234 mm×1 mm, 80 slices). We applied micro-finite element analysis to 10-mm-thick volumes of interest at the distal femoral diaphysis, metaphysis, and epiphysis to compute stiffness and cross-sectional area of whole, cortical, and cancellous bone, as well as cortical thickness. We applied two-tailed t-tests and ANCOVA to compare groups.

RESULTS

Dancers demonstrated greater whole and cancellous bone stiffness and cross-sectional area at all locations (p<0.05). Cortical bone stiffness, cross-sectional area, and thickness did not differ between groups (>0.08). At all locations, the percent of intact whole bone stiffness for cortical bone alone was lower in dancers (p<0.05). Adjustment for cancellous bone cross-sectional area eliminated significant differences in whole bone stiffness between groups (p>0.07), but adjustment for cortical bone cross-sectional area did not (p<0.03).

CONCLUSIONS

Modern dancers have greater whole and cancellous bone stiffness in the distal femur compared to controls. Elevated whole bone stiffness in dancers may be mediated via cancellous, rather than cortical bone adaptation.

Clinical imaging of articular cartilage in the knee

Assessment of articular cartilage has become an essential part of magnetic resonance (MR) evaluation of the knee. This has occurred because of recent advances in treatment along with improved accuracy of MR image evaluation of articular cartilage. Detection of articular cartilage defects can provide an explanation for symptoms and allow identification of patients for cartilage therapy and is an important factor for predicting prognosis of patients with knee injury. This review describes the most easily implemented MR techniques for evaluation of articular cartilage and the normal and abnormal appearance of cartilage seen using these techniques. The influence of imaging findings on treatment is described.

Magnetic resonance imaging of the foot and ankle

Magnetic resonance (MR) imaging of the foot and ankle is playing an increasingly important role in the diagnosis of a wide range of foot and ankle abnormalities, as well as in planning for their surgical treatment. For an optimal MR study of the foot and ankle, it is necessary to obtain high-resolution, small-field-of-view images using a variety of pulse sequences. The most common indication for MR imaging of the foot and ankle is for the evaluation of tendon and bone abnormalities, such as osteomyelitis, occult fractures, and partial and complete tears of the Achilles, tibialis posterior, and peroneal tendons. Magnetic resonance imaging has also been shown to be helpful in the diagnosis of several soft-tissue abnormalities that are unique to the foot and ankle, such as plantar fasciitis, plantar fibromatosis, interdigital neuromas, and tarsal tunnel syndrome.

MR imaging of articular cartilage

With the advent of new treatments for articular cartilage disorders, accurate noninvasive assessment of articular cartilage, particularly with MR imaging, has become important. Understanding the MR imaging features of articular cartilage has led to the development of two types of routinely available MR imaging techniques which have demonstrated clinical accuracy and interobserver reliability.

Second time around: evaluating the postoperative anterior cruciate ligament

Anterior cruciate ligament (ACL) injuries are especially common in the younger athletic population. In 1998, more than 100,000 ACL reconstructions were performed. MR imaging examination has proved to be valuable in imaging and evaluating ACL reconstructions. This article reviews different surgical reconstruction procedures, indications for postoperative MR imaging, and the MR imaging appearance seen in routine ACL reconstructions and in complications associated with ACL reconstructions.

Outcomes of postoperative septic arthritis after anterior cruciate ligament reconstruction

Arthroscopically guided reconstruction of the anterior cruciate ligament is a common orthopaedic procedure. While many associated complications have been described in the literature, postoperative septic arthritis has received little attention. Although rare after anterior cruciate ligament reconstruction, septic arthritis can have devastating consequences. From a group of 831 consecutive patients, we report 4 (0.48%) who sustained septic arthritis. All patients had similar symptoms and were treated by the same surgeon in the same manner. All underwent immediate arthroscopic lavage, open incision, drainage of associated wounds, debridement with graft retention, and treatment with intravenous and then oral antibiotics. The patients underwent an average of 2.75 procedures after the diagnosis to eradicate the infection and restore knee motion. All patients were evaluated at an average of 3 years after surgery. We found that previous knee surgery and meniscal repair were risk factors for the development of postoperative septic arthritis. The infection was successfully eradicated, the ligament graft was preserved, and knee stability and mobility were adequately restored in all patients. However, the clinical outcome of these patients appeared to be inferior to that of patients who had undergone uncomplicated anterior cruciate ligament reconstruction. This inferior outcome appeared to be secondary to damage to the articular cartilage from the infection.

MR arthrography of the adult acetabular capsular-labral complex: correlation with surgery and anatomy

OBJECTIVE

Our purpose was to describe the appearance of the acetabular capsular-labral complex on MR arthrography and to correlate this appearance with surgical findings in adult patients and with gross anatomic findings in cadavers.

SUBJECTS AND METHODS

MR arthrography of the hip joint was performed in 40 patients and six cadavers. All patients underwent subsequent arthrotomy of the hip. MR arthrography consisted of a T1-weighted three-dimensional gradient-echo sequence in both the coronal oblique and sagittal oblique planes after intraarticular injection of a 2 mmol/l solution of gadopentetate dimeglumine. The normal and pathologic appearance of the capsular-labral complex was assessed, and the labra were evaluated on the basis of morphology, signal intensity, presence of a tear, and attachment to the acetabulum. MR arthrography findings were correlated with the surgical results in all patients and with the anatomic sections of the cadaveric hip joint specimens.

RESULTS

MR arthrography images of the T-weighted three-dimensional gradient-echo sequences allowed visualization of the anatomic structures. The normal labrum was triangular, without any sublabral sulcus, and of homogeneous low signal intensity. A recess between the labrum and the joint capsule could be identified in instances in which no thickened labrum was present. Labral lesions included labral degeneration, a tear, or a detached labrum either with or without thickening of the labrum. The sensitivity for detection and correct staging of labral lesions with MR arthrography in the patient study was 91%; the specificity, 71%; and the accuracy, 88%.

CONCLUSION

MR arthrography with T1-weighted three-dimensional gradient-echo sequences allows excellent assessment of the normal and pathologic acetabular capsular-labral complex.

Selenium-based digital radiography versus conventional film-screen radiography of the hands and feet: a subjective comparison

OBJECTIVE

The purpose of this study was to subjectively compare the visibility of normal anatomy of the hands and feet using selenium-based digital radiography versus conventional film-screen (100-speed) radiography.

SUBJECTS AND METHODS

Digital and film-screen images of the hands and feet of 24 patients were obtained without an antiscatter grid using identical X-ray exposure. Each pair of images was evaluated independently by five experienced radiologists for visibility of normal anatomy using a six-point rating scale. Soft tissues, cortical bone, and trabeculae were evaluated. For each observer, "equivalence" was defined as a mean difference in image quality of less than 1 unit on the 0-5 scale used in the study. Paired t tests were also performed to determine whether the average visibility rating of one technique was statistically superior to that of the other at a .05 level of significance for each observer and at each anatomic landmark.

RESULTS

In all categories, selenium-based digital images were rated equivalent to film-screen images by the five observers. Using the sum of the nine landmarks, four of the five observers rated the quality of selenium-based digital images superior to that of film-screen images.

CONCLUSION

Subjective visibility of normal anatomy of the hands and feet using selenium-based digital radiography was similar to that achieved using conventional film-screen radiography.

Magnetic resonance imaging of articular cartilage: an overview

MR imaging is the best noninvasive method for the evaluation of articular cartilage. Recent studies have clarified the MR appearance of normal articular cartilage and proven that MR imaging can detect chondral lesions with high accuracy. Quantitative imaging holds promise for the accurate determination of cartilage volumes and thickness measurements, as well as the ability to detect early chondral degeneration and biochemical changes before gross morphologic changes occur.

Fat suppressed MRI of articular cartilage with a spatial-spectral excitation pulse

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.

Imaging modalities for study of the distal ulnar region

Judicious use of diagnostic imaging maximizes the diagnostic capabilities of the surgeon treating the distal radio-ulnar joint (DRUJ). A good clinical history and clinical examination are necessary to direct the selection of appropriate imaging studies. Plain radiographs are almost always the first imaging examination. More advanced imaging techniques are costly and may provide only limited information. This article discusses imaging modalities useful for assessment of the DRUJ and the area around it.

Acute calcific tendinitis of the hip: case report with magnetic resonance imaging findings

The clinical presentation of acute calcific tendinitis can be quite dramatic. This report describes a patient with this entity who had calcification in an unusual area, accompanied by abnormalities seen on radiography and magnetic resonance imaging. Clinical aspects of acute calcific tendinitis are also reviewed. With recognition of this entity, treatment can be initiated promptly, with dramatic resolution.

MR imaging of the knee ligaments and the postoperative knee

MR imaging is an accurate, noninvasive, and cost-effective method for the evaluation of acute knee ligament injuries and in the examination of the postoperative knee. Understanding the normal anatomy and the pertinent clinical aspects of knee injuries is a prerequisite for accurate interpretation of MR imaging studies. The increasing popularity of ACL reconstruction following disruption of this ligament requires knowledge of the various surgical techniques and their MR imaging appearance as well as the appearance of possible complications.

Lesions of the acetabular labrum: accuracy of MR imaging and MR arthrography in detection and staging

PURPOSE

To determine the accuracy of magnetic resonance (MR) imaging and MR arthrography in the detection and staging of lesions of the acetabular labrum.

MATERIALS AND METHODS

Fifty-seven hips of 56 patients with chronic hip pain and a strong clinical suspicion of labral lesions were examined with a three-dimensional gradient-echo sequence in the coronal oblique and sagittal oblique projections before and after the intraarticular injection of gadopentetate dimeglumine. The labra were evaluated on the basis of morphology, signal intensity, the presence or absence of a tear, and their attachment to the acetabulum. Twenty-two of the hips underwent surgical intervention, and 35 hips were treated conservatively.

RESULTS

Twenty of the 22 labra with surgical proof were staged accurately with MR arthrography. On the conventional MR images, only eight of the 22 labra were staged correctly. Whereas the sensitivity of MR arthrography was 90% and its accuracy was 91%, the sensitivity of MR imaging was 30% and its accuracy was 36%, compared with surgical findings.

CONCLUSION

MR arthrography enables accurate detection and staging of lesions of the acetabular labrum and appears to be indicated in the assessment of chronic hip pain in patients with a strong suspicion of labral lesions.

Acromial morphology: relation to sex, age, symmetry, and subacromial enthesophytes

PURPOSE

To evaluate acromial shape in relation to age, sex, symmetry, and presence of subacromial enthesophytes.

MATERIALS AND METHODS

Three hundred ninety-four cadaveric scapulas were reviewed. Specimens were categorized by sex and age (age range, 20-89 years). Acromial morphology was typed according to the Bigliani classification: type I, flat; type II, curved; and type III, hooked. The presence and degree of subacromial enthesopathy was recorded. Selective radiographic correlation was obtained.

RESULTS

The relative percentages of acromial types I, II, and III were 22.8% (90 acromions), 68.5% (270 acromions), and 8.6% (34 acromions), respectively. There was a greater percentage of type III in men (10.2% [21 of 205] vs 6.9% [13 of 189] and type I in women (27.5% [52 of 189] vs 18.5% [38 of 205]). There was no relationship between acromial type and age (P = .667). Enthesophytes were most common in type III (20 [59%] of 34 acromions) versus type II (115 [42.6%] of 270 acromions) and type I (22 [24%] of 90 acromions). Acromial morphology was symmetric in 135 (70.7%) of 191 pairs of acromions and asymmetric in 56 pairs (29.3%).

CONCLUSION

Acromial shape does not vary significantly with age. It does, however, differ between sexes. The relative percentages of the types differ from previously reported values. Acromial shape tends to be symmetric. A trend between acromial type and the presence of enthesophytes is observed.

Optimization of a dual echo in the steady state (DESS) free-precession sequence for imaging cartilage

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.

Accuracy of fat-suppressed three-dimensional spoiled gradient-echo FLASH MR imaging in the detection of patellofemoral articular cartilage abnormalities

PURPOSE

To determine the accuracy of T1-weighted fat-suppressed (FS) three-dimensional (3D) fast low-angle shot (FLASH) magnetic resonance (MR) imaging for the detection of articular cartilage abnormalities of the patellofemoral joint.

MATERIALS AND METHODS

Forty-one patients with suspected internal derangement of the knee were examined with a T1-weighted FS 3D FLASH sequence and subsequently underwent arthroscopy. The patellofemoral articular cartilage was graded blindly on both the MR and arthroscopic images with a modification of the Noyes classification scheme.

RESULTS

For the detection of abnormal articular cartilage of the patellofemoral joint with the FS 3D FLASH sequence, sensitivity was 81%, specificity was 97%, and accuracy was 97%. Of the lesions detected on MR images, 77% were graded identically on MR and arthroscopic images. For the remaining 23%, MR imaging and arthroscopic ratings were within one grade of each other.

CONCLUSION

T1-weighted FS 3D FLASH imaging is accurate for the detection and grading of articular cartilage abnormalities of the patellofemoral joint.

Adamantinoma

This is an unusual case of an adamantinoma in an early phase of evolution. It was much smaller than adamantinomas typically seen at presentation, although it was located in the usual anterior tibial cortical region. Slow growth and a prolonged period of symptoms are common with adamantinoma and were also observed in this patient. The multifocal presentation within the same bone is unusual. This case illustrated the need to consider adamantinoma in the differential diagnosis of any pre-tibial cortical lesion despite the small size, benign presentation, or the longevity of symptoms.

Localized anterior arthrofibrosis (cyclops lesion) after reconstruction of the anterior cruciate ligament: MR imaging findings

OBJECTIVE

A localized form of anterior arthrofibrosis, the so-called cyclops lesion, has recently been reported to be a significant cause of loss of knee extension after reconstruction of the anterior cruciate ligament (ACL) of the knee. The purpose of this study was to characterize the MR appearance of this lesion.

SUBJECTS AND METHODS

Five patients who had arthroscopic verification of a focal nodule of fibrous tissue in the intercondylar notch anterior to the reconstructed ACL (the cyclops lesion) and who had an MR examination after ACL reconstruction but before repeat arthroscopy and excision of the cyclops lesion were included in this study. The MR images were evaluated for the presence of soft tissue in the intercondylar notch anterior to the reconstructed ACL. If present, this tissue was graded as 1, 2, or 3, depending on its anterior extent along the femoral condyle.

RESULTS

MR images of all five patients showed abnormal soft tissue with signal characteristics consistent with fibrous tissue anterior to the reconstructed ACL in the intercondylar notch. The abnormal tissue was grade 2 or 3 in all patients.

CONCLUSION

MR imaging shows soft tissue with signal characteristics consistent with fibrous tissue anterior to the reconstructed ACL in the intercondylar notch in patients with localized anterior arthrofibrosis. Although the sensitivity and specificity of MR imaging for the cyclops lesion are yet to be determined, visualization of such fibrous tissue on MR images in a patient with clinical symptoms suggestive of localized anterior arthrofibrosis may be helpful in confirming the diagnosis.

Denervation hypertrophy of muscle: MR features

OBJECTIVE

Denervation hypertrophy is an entity well recognized in the neurology literature, but with little mention in the radiology literature. Denervation hypertrophy occurs when a muscle paradoxically enlarges rather than atrophies in response to loss of innervation. The purpose of this report is to describe the MR appearance of true hypertrophy and pseudohypertrophy of muscle following denervation.

MATERIALS AND METHODS

The clinical data and MRI findings in three patients with muscle enlargement due to denervation hypertrophy are reviewed retrospectively. Two women and one man aged 19-80 years were included. Denervation resulted from spinal stenosis in one patient, a herniated thoracic disc in another, and spina bifida with a tethered cord in the third.

RESULTS

True hypertrophy of a single muscle was seen in one patient and pseudohypertrophy of two muscles was present in one patient. One patient had one muscle with true hypertrophy and one muscle with pseudohypertrophy. Electromyographic examination was performed and was consistent with denervation in two patients. Biopsy confirmation of denervation was obtained in two patients. All five abnormal muscles exhibited increased volume, well defined margins, and normal contour. In true hypertrophy the enlarged muscle was isointense with normal muscle on all MRI sequences. In pseudohypertrophy the MRI appearance was consistent with an excessive amount of fat interspersed throughout normal muscle.

CONCLUSION

Magnetic resonance in these cases established muscle hypertrophy rather than neoplasm as the cause of a palpable mass. If muscle hypertrophy or pseudohypertrophy is seen on an MR examination of an enlarged extremity, the possibility of an underlying neurologic process should be considered.

Magnetic resonance imaging of articular cartilage: the state of the art

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.

The MR appearance of cruciate ganglion cysts: a report of 16 cases

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.

MR imaging of articular cartilage: current status and future directions

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.

Postcontrast MR arthrography in assessment of cartilage lesions

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.

Distribution of normal and abnormal fluid collections in the glenohumeral joint: implications for MR arthrography

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.

Isolated or dominant lesions of the patella in gout: a report of seven patients

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.

Abnormalities of articular cartilage in the knee: analysis of available MR techniques

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.

MR imaging of the pancreas at high field strength: comparison of six sequences

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.

Recurrent esophageal carcinoma at thoracotomy incisions: diagnostic contributions of CT

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.

Barrett's esophagus in scleroderma: increased prevalence and radiographic findings

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.

Radiology of wrist and hand injuries in athletes

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.

Vascular anomalies in association with osteodystrophies--a spectrum

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).