Camurati-Engelmann disease: unique variant featuring a novel mutation in TGFβ1 encoding transforming growth factor beta 1 and a missense change in TNFSF11 encoding RANK ligand

We report a 32-year-old man and his 59-year-old mother with a unique and extensive variant of Camurati-Engelmann disease (CED) featuring histopathological changes of osteomalacia and alterations within TGFβ1 and TNFSF11 encoding TGFβ1 and RANKL, respectively. He suffered leg pain and weakness since childhood and reportedly grew until his late 20s, reaching 7 feet in height. He had deafness, perforated nasal septum, torus palatinus, disproportionately long limbs with knock-knees, low muscle mass, and pseudoclubbing. Radiographs revealed generalized skeletal abnormalities, including wide bones and cortical and trabecular bone thickening in keeping with CED, except that long bone ends were also affected. Lumbar spine and hip BMD Z-scores were + 7.7 and + 4.4, respectively. Biochemical markers of bone turnover were elevated. Hypocalciuria accompanied low serum 25-hydroxyvitamin D (25[OH]D) levels. Pituitary hypogonadism and low serum insulin-like growth factor (IGF)-1 were present. Karyotype was normal. Despite vitamin D repletion, iliac crest histology revealed severe osteomalacia. Exon 1 of TNFRSF11A (RANK), exons 2, 3, and 4 of LRP5, and all coding exons and adjacent mRNA splice junctions of TNFRSF11B (OPG), SQSTM1 (sequestosome 1), and TNSALP (tissue nonspecific alkaline phosphatase) were intact. His asymptomatic and less dysmorphic 5'11″ mother, also with low serum 25(OH)D, had milder clinical, radiological, biochemical, and histopathological findings. Both individuals were heterozygous for a novel 12-bp duplication (c.27_38dup, p.L10_L13dup) in exon 1 of TGFβ1, predicting four additional leucine residues in the latency-associated-peptide segment of TGFβ1, consistent with CED. The son was also homozygous for a single base transversion in TNFSF11, predicting a nonconservative amino acid change (c.107C > G, p.Pro36Arg) in the intracellular domain of RANKL that was heterozygous in his nonconsanguineous parents. This TNFSF11 variant was not found in the SNP Database, nor in published TNFSF11 association studies, but it occurred in four of the 134 TNFSF11 alleles (3.0%) we tested randomly among individuals without CED. Perhaps the unique phenotype of this CED family is conditioned by altered RANKL activity.

Buschke-Ollendorff syndrome: absence of LEMD3 mutation in an affected family

BACKGROUND

Buschke-Ollendorff syndrome (BOS), an autosomal dominant disorder, features small, acquired, asymptomatic, symmetrical foci of osteosclerosis detected radiographically in epimetaphyseal bone (osteopoikilosis) (OPK) together with connective tissue nevi or juvenile elastomas. Heterozygous, loss-of-function, germline mutation in the LEMD3 gene (which encodes an inner nuclear membrane protein called LEMD3, or MAN1) has been repeatedly documented in patients with BOS or OPK.

OBSERVATIONS

We describe a father and son with multiple yellowish papules and nodules coalescing into cobblestone nevoid plaques consistent with nevus elasticus. Radiographs of the father show multiple, small, bone islands within the hands, wrists, distal femurs, proximal tibias, and left distal fibula consistent with OPK. Although the clinical findings are diagnostic of Buschke-Ollendorf syndrome, analysis of the LEMD3 gene showed no exonic mutations.

CONCLUSION

Absence of LEMD3 mutation in the exons and splice sites of a family with BOS suggests that there is genetic heterogeneity for this disorder.

Juvenile Paget's disease: the second reported, oldest patient is homozygous for the TNFRSF11B "Balkan" mutation (966_969delTGACinsCTT), which elevates circulating immunoreactive osteoprotegerin levels

The oldest person (60 yr) with juvenile Paget's disease is homozygous for the TNFRSF11B mutation 966_969delTGACinsCTT. Elevated circulating levels of immunoreactive OPG and soluble RANKL accompany this genetic defect that truncates the OPG monomer, preventing formation of OPG homodimers.

INTRODUCTION

Juvenile Paget's disease (JPD), a rare autosomal recessive disorder, features skeletal pain, fracture, and deformity from extremely rapid bone turnover. Deafness and sometimes retinopathy also occur. Most patients have diminished osteoprotegerin (OPG) inhibition of osteoclastogenesis caused by homozygous loss-of-function defects in TNFRSF11B, the gene that encodes OPG. Circulating immunoreactive OPG (iOPG) is undetectable with complete deletion of TNFRSF11B but normal with a 3-bp in-frame deletion.

MATERIALS AND METHODS

We summarize the clinical course of a 60-yr-old Greek man who is the second reported, oldest JPD patient, including his response to two decades of bisphosphonate therapy. Mutation analysis involved sequencing all exons and adjacent mRNA splice sites of TNFRSF11B. Over the past 4 yr, we used ELISAs to quantitate his serum iOPG and soluble RANKL (sRANKL) levels.

RESULTS

Our patient suffered progressive deafness and became legally blind, although elevated markers of bone turnover have been normal for 6 yr. He carries the same homozygous mutation in TNFRSF11B (966_969delTGACinsCTT) reported in a seemingly unrelated Greek boy and Croatian man who also have relatively mild JPD. This frame-shift deletes 79 carboxyterminal amino acids from the OPG monomer, including a cysteine residue necessary for homodimerization. Nevertheless, serum iOPG and sRANKL levels are persistently elevated.

CONCLUSIONS

Homozygosity for the TNFRSF11B "Balkan" mutation (966_969delTGACinsCTT) causes JPD in the second reported, oldest patient. Elevated circulating iOPG and sRANKL levels complement evidence that this deletion/insertion omits a cysteine residue at the carboxyterminus needed for OPG homodimerization.

Value of Magnetic Resonance Imaging in Muscle Trauma

While most muscle injuries are recognized clinically, magnetic resonance imaging (MRI) is the ideal noninvasive test to assess their extent and severity, which impacts therapy and influences prognosis. Typical examples of these injuries include muscle contusions, lacerations, sprains, and delayed onset muscle soreness. For other less common traumatic muscle conditions (exertional compartment syndrome, muscle herniation, and traumatic denervation), the clinical findings are often subtle or ambiguous and MRI will indicate the correct diagnosis. In patients with known muscle trauma, MRI can detect complications such as hematoma or seroma development, scarring and fibrosis, and myositis ossificans. This article illustrates the spectrum of muscle injuries, emphasizing the value of MRI in their diagnosis.

Proximity of the popliteal artery to the PCL during simulated knee arthroscopy: implications for establishing the posterior trans-septal portal

This study defines the sagittal distance from the posterior cruciate ligament (PCL) to the popliteal artery under simulated arthroscopic conditions. This information is relevant for posterior knee arthroscopy, particularly for the safe establishment of the posterior trans-septal portal. Measurements from the PCL to the popliteal artery were made on sagittal magnetic resonance images obtained in a previous study of 10 fresh-frozen cadaveric knees. The mean sagittal distance from the mid-PCL to the popliteal artery was 29.1 +/- 11 mm (range: 18-55 mm). The mean sagittal distance from the proximal PCL fovea to the popliteal artery was 9.7 +/- 5 mm (range: 3-16 mm). The results of this study provide the arthroscopist working in the posterior compartments of the knee with a more detailed knowledge of the anatomic relationship between the PCL and popliteal artery. This knowledge will help minimize the risk of iatrogenic vascular injury during arthroscopic knee surgery.

Giant vertebral notochordal rest: a lesion distinct from chordoma: discussion of an evolving concept

A 14-year-old boy with severe back pain for several years is described. Roentgenograms, bone scans, and computed tomographic scans of the spine were normal, but magnetic resonance imaging studies showed a lumbar vertebral body lesion, confined to the bone, with low T1- and high T2-weighted signal intensities. Histologically, the lesion consisted of sheet-like notochordal-type tissue, containing physaliphorous cells but lacking the usual features of chordoma. A diagnosis of giant notochordal rest was made. A review of prior possible examples of this recently described and controversial entity is made with a discussion of its embryologic foundations and distinction from chordoma.

Imaging findings in pseudocystic osteosarcoma

OBJECTIVE

Our purpose was to describe four female patients with osteosarcoma whose clinical and imaging findings primarily suggested either simple or aneurysmal bone cyst. All lesions were osteolytic, intracompartmental, and expanded bone without periosteal reaction. None of the patients presented during the peak age incidence for osteosarcoma. From imaging to histologic diagnosis, the discovery of osteosarcoma ranged from 1 week to 3 years.

CONCLUSION

Atypical osteosarcoma may rarely mimic simple or aneurysmal bone cyst radiologically and may show a nonmalignant rate of growth. It may be more frequently encountered in females and may not present during the peak age incidence for osteosarcoma. Microscopically, the tumors were not cystic, necrotic, or telangiectatic but were conventional osteosarcoma and osteoclast-rich osteosarcoma.

Proximity of the posterior cruciate ligament insertion to the popliteal artery as a function of the knee flexion angle: implications for posterior cruciate ligament reconstruction

PURPOSE

The purpose of this study was to determine if an optimal knee flexion angle existed that would minimize the risk of neurovascular injury from the passage of transtibial hardware during posterior cruciate ligament (PCL) reconstruction.

TYPE OF STUDY

Cadaveric.

MATERIALS AND METHODS

Fourteen fresh-frozen cadaveric knees were mounted in a Plexiglas apparatus that could be set at 5 different knee flexion angles (0 degrees, 45 degrees, 60 degrees, 90 degrees, and 100 degrees ) while joint distention was maintained. Each knee underwent magnetic resonance imaging in the axial and sagittal planes at each of the 5 flexion angles to determine the distance between the PCL tibial insertion and popliteal artery.

RESULTS

The mean distance, over all 5 flexion angles, between the PCL insertion and the popliteal artery in the axial plane was 7.6 mm, whereas the mean distance in the sagittal plane was 7.2 mm. There was a significant increase in distance with progressive flexion in both planes. Maximum mean distances were noted at 100 degrees of flexion in both the axial (9.9 mm) and sagittal (9.3 mm) planes. An artificial line mimicking the path of a transtibial drill passed through the popliteal artery in 10 of 10 cases at the 0 degrees, 45 degrees, 60 degrees, and 90 degrees angles, and in 6 of 10 cases at the 100 degrees angle.

CONCLUSIONS

The results of this study suggest that increasing knee flexion reduces, but does not completely eliminate, the risk of arterial injury during arthroscopic PCL reconstruction.

Solitary skeletal hemangioma of the extremities

OBJECTIVE

To report the clinicopathologic features of solitary skeletal hemangioma of the extremities and to review previous cases in the English language medical literature.

PATIENTS

In addition to five of our own cases, 34 literature cases with substantial and 75 with partial clinicopathologic information were found.

RESULTS

Our patients, three men and two women, ranged in age from 37 to 83 years (mean 65.6 years). The lesion was an incidental radiologic finding in two patients, while three were symptomatic. In no case was a correct preoperative radiologic diagnosis made, a malignant process being considered as a possibility in all. The hemangiomas were medullary; two involved a metacarpal, two the fibula, and one the humerus. In contrast, previously reported patients were younger (mean age 32 years), predominantly female (60%), and symptomatic in over 90% of cases. The lesion is rare in those younger than age 10 years or older than age 60 years. As in our patients, the long bones are most frequently involved (75%), with the diaphysis or metadiaphysis, as in four of our patients, the most common locations. Although 20% of cases occur in the hands or feet, metacarpal involvement is rare. Medullary origin, as in all of our cases, is most frequent, but 45% of cases are either periosteal (33%) or intracortical (12%). In the literature, cavernous hemangioma is the most frequent type. Three of our hemangiomas were cavernous, one capillary, and one venous, the latter being rarely reported in extremity bones.

CONCLUSIONS

Due to the diversity of radiologic patterns produced by skeletal hemangioma, a correct preoperative diagnosis is rarely made. Almost all patients do well, even those with less than complete removal of the lesion; local recurrence is rare. All of our patients were well following either therapeutic or simple diagnostic procedures. Due to the destructive nature of some biopsy procedures, the histologic diagnosis of hemangioma may at times also be problematic.

Imaging the postoperative meniscus

Patients who have undergone meniscal repair or resection and who develop new symptoms frequently are referred for MR imaging. In the postoperative meniscus, however, the standard MR imaging criteria for meniscal tears cannot be applied to diagnose recurrent or residual tears because signal and shape abnormalities are expected postoperative findings. This article reviews the MR imaging findings that can be used for diagnosing recurrent tears and demonstrates the usefulness of MR arthrography in the evaluation of the postoperative meniscus.

Synovial chondromatosis in a facet joint of a cervical vertebra

STUDY DESIGN

A case report of a cervical facet joint synovial chondromatosis.

OBJECTIVES

To correlate the radiologic and histologic features of vertebral synovial chondromatosis with review of the literature.

SUMMARY OF BACKGROUND DATA

Only two previous cases of vertebral facet joint synovial chondromatosis were found in a review of the English language medical literature.

METHODS

A 39-year-old woman had severe cervical pain associated with neurologic signs and symptoms in the left upper extremity. Computed tomographic and magnetic resonance imaging studies were performed.

RESULTS

Imaging studies showed lytic defects in the laminae of C3 and C4, with intermediate T1 and high T2 signal intensities. The diagnostic impression was that of a lymphangioma or synovial cyst. A laminectomy showed synovial tissue in both the C3-C4 facet joint and the lamina bone. Histologic examination disclosed synovial chondromatosis.

CONCLUSIONS

Synovial chondromatosis of the vertebral spine is quite rare, this being only the third reported example. Direct invasion of the cancellous bone, as in this case, also is a very uncommon feature of chondromatosis. It is emphasized that when radiologic studies demonstrate a lesion with cartilaginous characteristics within or juxtaposed to a joint, synovial chondromatosis, despite its rarity, should be included in the differential diagnosis, regardless of the anatomic site.

Pictorial review: magnetic resonance imaging of benign soft tissue masses of the hand and wrist

Magnetic resonance imaging (MRI) is the imaging method of choice for evaluating the presence and extent of soft tissue masses. It is particularly useful for assessing masses in the wrist and hand, where benign lesions predominate. A specific diagnosis may be made, or strongly suspected, from the characteristic MRI features found in certain conditions like ganglion, haemangioma, arteriovenous malformation, giant cell tumour of the tendon sheath and lipoma.

MR diagnosis of rotator cuff tears of the shoulder: value of using T2-weighted fat-saturated images

OBJECTIVE

The purpose of this study was to compare the use of fat-saturated T2-weighted spin-echo MR imaging with that of conventional T2-weighted spin-echo MR imaging to detect full- and partial-thickness tears of the rotator cuff of the shoulder, using arthroscopy as the standard for the diagnosis.

SUBJECTS AND METHODS

Forty-nine consecutive patients with shoulder pain who had both MR imaging and arthroscopy of their affected shoulders were studied. The study group consisted of 10 patients with full-thickness tears of the rotator cuff, 20 with partial-thickness tears of the rotator cuff, and 19 with intact rotator cuff tendons proved arthroscopically. All patients had T1-weighted, conventional T2-weighted, and fat-saturated T2-weighted MR images obtained in a plane slightly oblique to the coronal plane along the long axis of the supraspinous tendon. The images were divided into two sets, one including both T1-weighted and conventional T2-weighted images, the other including T1-weighted and fat-saturated T2-weighted images. Two musculoskeletal radiologists reviewed each set of MR images in a blinded fashion. The reviewers were asked to decide whether the rotator cuff showed a full-thickness tear, a partial-thickness tear, or no tear on each set of images. In the case of partial-thickness tears, the reviewers were asked to indicate which surface (bursal or joint) of the rotator cuff was affected. These data were correlated with the arthroscopic findings and with each other using McNemar and kappa analysis.

RESULTS

Detection of full-thickness tears was excellent for both reviewers using either imaging technique. However, when the fat-saturated technique was used, the sensitivity increased significantly, from 80% to 100%. Detection of partial-thickness tears was poor with conventional spin-echo MR imaging (15%). Although significantly improved when fat saturation was used (35%), detection rates were still lower than rates reported in the literature. Identification of the torn surface of the rotator cuff was correct in 50% of cases in which partial-thickness tears were successfully identified. Fat saturation decreased the specificity of identification of both partial and full-thickness tears of the rotator cuff but significantly increased the specificity with which intact rotator cuffs were identified.

CONCLUSION

Use of the fat-saturation technique improved detection of both full-thickness and partial-thickness tears of the rotator cuff on MR images compared with standard spin-echo imaging techniques. Despite this improvement, detection of partial-thickness tears was poor with both techniques. Furthermore, correct identification of which surface of the rotator cuff was torn in patients with partial tears was nearly random.

Acromial arch shape: assessment with MR imaging

PURPOSE

To test the hypothesis that acromial shape is comparable on supraspinatus outlet view radiographs and parasagittal magnetic resonance (MR) images.

MATERIALS AND METHODS

Supraspinatus outlet view radiographs of a dried scapula were obtained in the neutral position and with various degrees of caudal, cranial, anterior, and posterior angulation. Sagittal MR images of 41 asymptomatic and 39 symptomatic shoulders were reviewed and compared with outlet view radiographs from the 39 symptomatic cases. Acromial shape was assessed with published classification schemes.

RESULTS

Minor variations in angulation produced changes in apparent acromial shape and thickness on the radiographs. MR imaging from a lateral to a more medial section changed the shape or thickness grade in 39 of 41 asymptomatic shoulders. There was poor correlation between findings at radiographic and MR assessment of acromial shape in the symptomatic group.

CONCLUSION

Apparent acromial shape is sensitive to minor changes in radiographic technique and MR section viewed.

MR appearance of cystic fibrous dysplasia

The radiologic and MR appearances of cystic fibrous dysplasia (FD) along with pathologic correlation are reported in a symptomatic patient. As a guide for operative intervention, MRI is helpful in both characterizing the lesion and its internal structure and determining the extent of osseous involvement. Cystic FD without an aneurysmal bone cyst component has not been previously reported in the radiologic literature.

The normal shoulder: common variations that simulate pathologic conditions at MR imaging

The appearance of the supraspinatus tendon and anterior capsular mechanism was analyzed in 60 asymptomatic shoulders with magnetic resonance (MR) imaging. The images were reviewed with special attention to findings that simulate pathologic conditions, as defined by means of currently accepted criteria. On T1-weighted and proton-density (PD) spin-echo (SE) images, intermediate signal intensity was present within the supraspinatus tendon in most shoulders. Focal signal intensity within the distal tendon was particularly common finding, being present in 95% (57 of 60) of shoulders on PD images. Focal obliteration of the subacromial-subdeltoid fat stripe and acromioclavicular joint arthrosis were seen in 95% (57 of 60) and 48% (29 of 60) of the subjects, respectively. There was considerable variation in the shape of the anterior glenoid labrum-glenohumeral ligament (GHL) complex. The labrum may appear triangular, round, crescentic, or absent. The middle and inferior GHLs lie in proximity to the upper half of the anterior labrum; the cleavage plane between the ligaments and the labrum can mimic a tear at MR imaging.

Characterization of musculoskeletal masses using dynamic Gd-DTPA enhanced spin-echo MRI

Early studies evaluating the utility of Gd-diethylenetriamine pentaacetic acid (DTPA) enhanced MR imaging for characterization of musculoskeletal masses have demonstrated inconsistent and often conflicting results. In this study a new method, dynamic Gd-DTPA enhanced rapid acquisition spin echo MR imaging, was implemented in the evaluation of 18 musculoskeletal lesions and the enhancement features of these lesions were analyzed. Lesions were evaluated before, during, and sequentially following bolus Gd-DTPA injection. Analysis of intensity, volume, timing of onset, progression, uniformity, and pattern of enhancement did not demonstrate significant differences between benign (n = 8) and malignant (n = 10) masses. Significant variations in enhancement were noted in different regions within these masses, which limits the utility of previous dynamic contrast enhanced methods that provide only a single imaging slice for analysis, and are therefore subject to sampling error. This pilot study indicates no advantage for using dynamic Gd-DTPA enhanced imaging for qualitative lesion characterization.

Calcaneal and pelvic fractures: diagnostic evaluation by three-dimensional computed tomography scans

A major application of three-dimensional (3D) computed tomography (CT) is in the imaging of the skeleton. 3D CT has a potentially important role in determining the presence, type, and extent of fractures, especially of the calcaneus and pelvis. The objective of this study was to compare the diagnostic sensitivity and specificity of 3D CT, CT slices, and plain radiography in the detection and characterization of calcaneal and pelvic fractures. 3D CT reconstructions were obtained by two methods, surface reconstruction and volumetric techniques. Twenty-eight patients were imaged with CT, 3D CT, and plain radiography. The opinion of a musculoskeletal radiologist with access to all images plus clinical history, surgical findings, and follow-up findings was taken as truth. Four additional musculoskeletal radiologists read these cases in a blinded fashion and ranked the modalities with regard to perceived utility. Receiver operating characteristic analysis was used to determine the relative value of each modality in terms of diagnostic quality. All imaging modalities performed comparably in the diagnosis of fractures. CT slices and plain-films were the most useful for more difficult diagnostic tasks such as fracture stability, and the presence of comminution and estimation of the number of fragments. The results suggest that for skeletal areas with complicated anatomy (such as the pelvis and calcaneus), the diagnostic value of 3D CT is often equivalent to that of conventional methods.

MR examination of the knee: interpretation with multiscreen digital workstation vs hardcopy format

A multiscreen imaging workstation was compared with conventional hardcopy format for diagnostic interpretation of MR images of the knee. MR examinations from 30 patients were interpreted by two observers using film displayed both on a standard film panel alternator and an eight-screen digital workstation. Arthroscopic examination of these patients disclosed 30 meniscal tears and five anterior cruciate ligament tears in 28 patients. Two patients had normal arthroscopic examinations. The MR examinations were evaluated with a five-point confidence rating scale. Results were correlated with arthroscopic findings, and receiver-operating-characteristic curves were generated from these data. No significant difference was found between the areas under the receiver-operating-characteristic curves for film and digital display. The time required for image interpretation was greater when using the digital workstation than when using the film by a factor of approximately 2.7. Our data indicate that a multiscreen digital workstation can be used for interpreting MR examinations of the knee without impairment of diagnostic performance, but with increased time required for image interpretation when compared with radiographic film and a film panel alternator.

Renal transplants: can acute rejection and acute tubular necrosis be differentiated with MR imaging?

Magnetic resonance (MR) imaging was used in 40 renal transplant recipients to determine whether this modality can enable distinction of acute tubular necrosis (ATN) and acute rejection by means of corticomedullary differentiation (CMD). Each patient underwent initial MR imaging after allograft renal transplantation. Twenty-nine of these 40 patients (72%) also underwent subsequent follow-up MR imaging. Seventeen studies were obtained during episodes of ATN; 12 of these studies (71%) showed poor CMD. Eleven studies were obtained during episodes of acute rejection; eight of these studies (73%) showed poor CMD. In addition, six of seven studies (86%) showing various combinations of renal disease (ATN, acute rejection, chronic rejection, and cyclosporine toxicity) also showed poor CMD. Loss of CMD is reversible after improvement of ATN and acute rejection. Because loss of CMD is a nonspecific though sensitive sign reflecting renal transplant dysfunction, MR imaging is of limited value in the differentiation of ATN from acute rejection.

Cross-sectional imaging of the patellofemoral joint and surrounding structures

Computed tomography (CT) and magnetic resonance (MR) imaging are extremely useful in the accurate diagnosis of anterior knee pain, a common complaint arising from numerous causes (including fracture, chondromalacia patellae, and alignment and tracking abnormalities). Plain CT is effective for evaluating intraosseous lesions of the knee. Although CT arthrography provides excellent visualization of the patellar articular cartilage, the technique is expensive and invasive. Cine CT is an excellent method for assessing patellofemoral tracking and alignment. Kinematic MR imaging can also perform this function. In addition, MR imaging can provide valuable information concerning the status of patellar cartilage. Although MR imaging can accurately show high-grade chondromalacia patellae, it is less accurate in the detection of low-grade disease. The authors believe that MR imaging and plain radiography offer radiologists the greatest latitude in making a specific diagnosis of the cause of anterior knee pain; however, CT is a useful alternative.

Magnetic resonance imaging of peripheral nerve sheath tumors. Assessment by numerical visual fuzzy cluster analysis

A retrospective, nonblinded review of ten nerve sheath tumors (four malignant) selected for pathologic proof and complete magnetic resonance (MR) evaluation was performed to assess the primary tumor location, signal pattern, and extent of reactive zone. A modification of visual fuzzy cluster analysis (VFCA) that emphasized the number of visual fuzzy clusters in each mass was developed to assess the neural tumors. The MR findings were correlated with the findings at surgery and histopathology. There were six men and four women, aged 19 to 62 years (mean, 43). Nine tumors involved the lower extremity. In all tumors, MRI correctly identified the nerve trunk of origin. Tumor dimensions were generally overestimated by MRI. Three internal signal patterns were observed: homogeneous (1/1 benign), finitely inhomogeneous (5/5 benign), and hectically inhomogeneous (4/4 malignant). The number of visual fuzzy clusters (VFCRs) for each sequence did not allow reliable separation of benign and malignant entities, but when considered in aggregate, benign and malignant lesions segregated in different clusters. This implies that the likelihood of malignancy increases as the number of MR-identifiable tissue types per lesion increase. Three types of reaction (edema) were observed best on long repetition time/echo time (TR/TE) sequences, confined to immediate peritumoral region, intracompartmental, and extracompartmental. The first two patterns correlated well with clinicopathologic findings; however, the third pattern did not. Separation of indolent (benign) cellular masses from aggressive (malignant) ones by MR characteristics is difficult but VFCA shows promise for aiding this differentiation and deserves further investigation in larger study populations.

The knee after partial meniscectomy: MR imaging features

The magnetic resonance (MR) examinations of 51 menisci treated by means of partial meniscectomy were reviewed. Menisci were divided into three groups: group 1, near normal length without osteoarthritis; 2, substantially shortened without osteoarthritis; and 3, any length with osteoarthritis. Group 1 menisci resembled normal menisci except for mild shortening and frequent signal inhomogeneity (56%). Group 2 menisci varied in appearance, with marked contour irregularity simulating fragmentation in 40% of segments despite a normal postoperative appearance at follow-up arthroscopy. Group 3 menisci appeared similar to menisci of the same length without osteoarthritis. Arthroscopic correlation, available for 23 menisci (45%), confirmed the MR diagnosis of a tear in 11 and no tear in 49 and revealed an unsuspected tear in three meniscal segments. There is a spectrum of normal MR appearances after partial meniscectomy. Standard MR criteria can be used to diagnose tears in the absence of marked contour irregularity; however, the diagnosis of tears of segments with marked contour irregularity must be made cautiously, since this irregularity can mimic a tear and was not predictive of an arthroscopically visible tear.

Subtalar arthrosis: evaluation with CT

The surgical implantation of a Silastic wedge into the lateral subtalar joint (subtalar arthrosis) is designed to restrict the osseous malalignment associated with a flexible or neurogenic flatfoot deformity. We used CT to examine patients who had persistent pain after a subtalar arthrosis and retrospectively reviewed our experience with CT scans of 13 subtalar implants (seven patients) during a 3.5-year period. The CT scans of four asymptomatic subtalar implants showed each implant in the expected position and orientation, and the findings were considered normal. Conversely, the findings on CT scans of all nine painful implants (seven patients) were interpreted as abnormal. The scans showed oblique orientation of four implants (44%), loosening of three implants (33%), extruded methyl methacrylate in the subtalar joint in two implants (22%), and abnormal calcaneal recession in two implants (22%). Five of the nine painful implants were revised with improvement or resolution of symptoms. Our experience suggests that CT scanning of the subtalar joint can show the position and orientation of a subtalar implant and identify causes of persistent pain after a subtalar arthrosis.

MR imaging of the knee: comparison of three-dimensional FISP and two-dimensional spin-echo pulse sequences

Two-dimensional (2D) spin-echo (SE) sequences and three-dimensional (3D) FISP (fast imaging with steady precession) sequences of the knee with the same section thickness and field of view were directly compared in 54 patients, 17 of whom underwent subsequent follow-up (15 arthroscopic and two arthrographic examinations). In those patients with follow-up, each sequence demonstrated 100% sensitivity, 80% specificity, and 94% accuracy for evaluation of the medial meniscus and 100% sensitivity, 100% specificity, and 100% accuracy for evaluation of the lateral meniscus. SE imaging demonstrated 100% sensitivity, 100% specificity, and 100% accuracy for evaluation of the anterior cruciate ligament, while 100% sensitivity, 82% specificity, and 88% accuracy were achieved with FISP imaging. In the 37 patients without follow-up, only two discrepancies were found between the 2D SE and the 3D FISP images for meniscal evaluation. Three discrepancies were found in the evaluation of the anterior cruciate ligament, two of which were likely false-positive 3D FISP results. We conclude that 2D SE and 3D FISP imaging provide comparable data for meniscal evaluation. FISP images are slightly less accurate than SE images of comparable resolution for the evaluation of the anterior cruciate ligament.

Shoulder joint: arthrographic CT and long-term follow-up, with surgical correlation

One hundred two computed tomographic (CT) arthrograms of the shoulder were retrospectively reviewed and compared with conventional double-contrast arthrograms from 101 patients (24 females and 77 males aged 9-70 years). One- to 4-year follow-up was obtained in 84 patients, 40 of whom underwent open-shoulder surgery or arthroscopy. Morphology of the normal portions of each labrum was categorized according to length, width, and tip shape. Correlation between morphology and age was weak, but abnormal labra were more common in younger patients. Conventional radiography was more accurate for detecting bony glenoid margin fractures, but CT was more accurate for detecting Hill-Sach fractures. CT was also more reliable than conventional arthrography in the detection of rotator cuff tears. Hence, few if any conventional radiographs are necessary between contrast material injection and CT imaging. A reduction in the number of images obtained will result in decreased radiation dose, less cost, and shorter examination time without loss of diagnostic accuracy.

Proton spectroscopic imaging (Dixon method) of the liver: clinical utility

The contribution of proton spectroscopic (PS) imaging to magnetic resonance (MR) imaging of the liver was assessed at 0.5 T in 55 patients with known or suspected hepatic malignancy. PS images were compared subjectively with T1- and T2-weighted spin-echo (SE) images for hepatic lesion detection and conspicuity. For hepatic metastases (n = 27), PS images were equal to T1-weighted images in lesion detection in 17 patients but showed fewer lesions in five patients and false-negative results in two. When compared with T2-weighted images, PS images depicted more lesions in six patients, an equal number of lesions in 18, and fewer lesions in two. Hepatomas (n = 8) were detected with each sequence in all patients. Hepatomas were often more conspicuous on PS images than on T2-weighted images; they were of equal conspicuity on PS and T1-weighted images in most cases. Whereas fatty infiltration (n = 16) appeared on PS images as areas of low signal intensity similar to that of paraspinal muscle, it produced no detectable abnormality on either T1- or T2-weighted images. PS imaging is inferior to T1-weighted SE imaging in the detection of hepatic metastases. The major role of PS imaging at intermediate field strength is to differentiate focal fatty infiltration from hepatic metastases.

Ascending lower limb phlebography: comparison of ioversol and iothalamate meglumine

Fifty patients undergoing ascending phlebography of a lower limb were evaluated, in a randomized double-blind fashion, to compare the efficacy, patient tolerance, and safety of two different contrast agents. Ioversol-240 (MP-238), a new nonionic agent, and iothalamate-202 (Conray 43), an established ionic agent, were the contrast agents used. Twenty-five patients were injected with iothalamate and 25 with ioversol. The phlebograms were evaluated for diagnostic quality and the patients for symptoms, with special reference to complaints of heat and pain. No significant difference was demonstrated between the two agents in either examination quality or patient tolerance. No major contrast-related reactions were recorded. We conclude that ioversol-240 appears to be a safe and acceptable alternative to iothalamate-202.

Measurement of fat distribution by magnetic resonance imaging

Because of the important role of intra-abdominal fat in predicting increased risk for diabetes, hypertension, and heart disease, methods to quantify intra-abdominal fat are needed. Computed tomography defines quantity of intra-abdominal fat but is associated with significant radiation risk. We explored using magnetic resonance imaging (MRI) to measure amount and distribution of intra-abdominal fat. Because MRI has no known risk, the same subject can be studied repeatedly. Six subjects with percent body fat ranging from 14% to 44% had MRI scans of the chest, abdomen, and thigh on two separate occasions. Total abdominal fat and subcutaneous abdominal fat correlated with percent total body fat as determined from hydrostatic weighing (r = .99, P less than .001). Intra-abdominal fat correlated with the ratio of widest abdominal to widest hip circumference (r = .85, P less than .05). Reproducibility of the MRI measurements of fat was less than 3% for total body areas, less than 5% for subcutaneous fat areas, and less than 10% for internal fat areas. Reproducibility was better in individuals with higher percent total body fat. We conclude that MRI can reliably measure fat areas with no radiation risk to the patient.

Radiographic evaluation of osteomyelitis using magnetic resonance imaging

Magnetic resonance imaging (MRI) is the newest evaluation procedure to be applied to the identification and study of osteomyelitis. MRI offers the sensitivity of scintigraphy but with far greater resolution. The differentiation of cellulitis from osteomyelitis can be made with greater accuracy than with scintigrams and MRI allows the identification of abscesses, sinus tracts, sequestra, and soft tissue abscesses with the reliability of computed tomography. Areas adjacent to metallic fixation devices show some signal loss but the distortion is less than with computed tomography. There is no risk to the patient caused by imaging with the fixation devices in place. The major problem in MRI use today is its relatively high cost, although it is less expensive than the combination of nuclear medicine studies often employed for the study of osteomyelitis.

Clinical MR imaging with a Helmholtz-type surface coil

Limited-field-of-view radio-frequency receiver antennas provide improved near-field sensitivity for magnetic resonance imaging by decreasing the antenna volume. The Helmholtz-type surface coil, consisting of two flat rings, is an organ-encompassing antenna that takes advantage of this principle to yield an improved signal-to-noise ratio (S/N). The coil was tested in a group of 50 patients and 16 healthy volunteers. Images obtained with the Helmholtz coil demonstrated quantitatively superior S/N of 2.2-fold or greater than that of comparison body coil images, as well as qualitatively superior anatomic resolution.

Arthrographic surface anatomy of the carpal triangular fibrocartilage complex

In a review of 364 radiocarpal and 123 distal radioulnar joint arthrograms we identified 44 (12%) patients with contrast defects at either the proximal or distal surface of the carpal triangular fibrocartilage complex (TFCC). Differences in their arthrographic characteristics distinguished two separate groups of patients; one with similar and another with dissimilar appearing TFCC surface contrast collections. Thirty-one of our 44 patients had similar appearing, isolated radial-sided collections at either the proximal or distal TFCC surfaces. Our arthrographic, demographic, and historical study of these patients suggests that the collections are not caused by traumatic partial TFCC tears but represent a normal anatomic variant, probably a synovial recess at the radial TFCC attachment. Arthrography and dissection of a limited number of cadaveric specimens confirmed this conclusion. The second group included the remaining 13 patients. This group had contrast collections at either the proximal or distal TFCC surface, which varied in location and appearance. This smaller group is more likely to represent those uncommon patients with partial TFCC defects caused by tears.

Transient osteoporosis: transient bone marrow edema?

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."

Arthrography after total hip arthroplasty: utility of postambulation radiographs

We compare pre- and postambulation arthrograms in 24 patients with total hip arthroplasty. In nearly half (42%) of these cases, the arthrographic evidence of a loosened prosthesis was more obvious after ambulation. Three patients (12.5%) had components which were normal by arthrographic criteria before walking, but were abnormal afterwards. We conclude that postambulation radiographs are valuable in patients who are examined for suspected loosening of prosthetic components.

CT-directed rib biopsy

A retrospective review of 11 cases of CT guided rib biopsy is presented. No complications occurred. In 10 of 11 cases open biopsy was averted. In this group the biopsy result is consistent with the remainder of the patients' test results and subsequent clinical course. Our series includes one false-negative biopsy. The true positive and negative biopsy results led to alterations in clinical management in each case. We conclude that CT-directed rib biopsy is a safe and useful procedure in carefully selected patients.

Fluoroscopic identification of torn intercarpal ligaments after injection of contrast material

Wrist arthrography is often used to evaluate the integrity of the scapholunate and lunotriquetral ligaments. This may be difficult when the ligaments are obscured by contrast material in standard radiographic projections, despite filming under fluoroscopic observation during the injection of contrast material. When superimposition occurs, we recommend fluoroscopic positioning of the wrist to optimally visualize the individual ligaments in profile. We applied this technique in performing 240 wrist arthrograms, 88 (37%) of which had scapholunate and/or lunotriquetral ligament tears. As a result, a definite diagnosis of the specific site of ligamentous disruption was possible in all but one case. Using this technique, we also identified six short-segment or "pinhole" ligamentous tears. Identification of commonly interrupted ligaments in profile by using fluoroscopy after contrast material has been injected may allow identification of specific ligamentous disruptions or short-segment tears, as well as a diagnosis of a specific anatomic abnormality that otherwise would not be possible.

Magnetic resonance imaging of the foot and ankle

Magnetic resonance imaging enhances the inherent differences in the density of tissues to allow the diagnosis of pedal disorders not readily observed by other diagnostic means. The technique is particularly useful for the evaluation of the nature and extent of soft tissue pathology. In addition, certain osseous and joint disorders, such as osteomyelitis and Sudeck's atrophy, may be detected in their incipient stages.

Arthrographic evaluation of the carpal triangular fibrocartilage complex

One hundred sixty-two patients had analyses for correlation of triangular fibrocartilage abnormalities (TFCC), with duration and location of pain and other possible associated radiographic, scintigraphic, and arthrographic abnormalities. Results indicated that TFCC perforations did not correlate with any pain complex or other associated radiographic, arthrographic, or scintigraphic abnormality. No association with carpal instability or with ulnar variance could be identified. No definition between perforations that were posttraumatic and those that were the results of a degenerative process could be made. Several small defects on both the proximal and distal surfaces of the TFCC were identified. They do not appear to have been reported previously in the literature. Their significance is discussed.

Posteroanterior wrist radiography: importance of arm positioning

Proper interpretation of wrist radiography requires a standardized radiographic technique. We obtained posteroanterior (PA) radiographs of the wrist in nine patients in three different arm positions to study the effect of arm position on ulnar styloid process orientation. An appearance simulating a normal anteroposterior (AP) wrist radiograph was present in six of nine PA radiographs when the arm was positioned next to the trunk, and the elbow was flexed to a 90% angle. The orientation of the ulnar styloid was not helpful in differentiating either pronated from supinated wrist positions or AP from PA projections. We concluded that radiographic screening of the carpus should be performed with standardized wrist positioning and nomenclature as described in modern radiographic technological texts. Supplemental projections should be exposed and interpreted with an understanding of the position of the arm and the direction of the incident radiographic beam at the time of examination.

Multispectral analysis of MR images of the breast

Preliminary investigations were conducted into the potential of magnetic resonance (MR) images for tissue classification of the breast on the basis of relative signal intensity. Multispectral techniques originally developed by the National Aeronautics and Space Administration for satellite image analysis were used in sequence selection, image data correction, image standardization, and image interpretation. Numerous sequence combinations with varying repetition times (TR) and echo times (TE) were considered, and a triplet was selected consisting of long TR/long TE, short TR/short TE, and an opposed phase sequence with intermediate TR and TE. Correction to remove system-imposed intensity inhomogeneities was required for all images. Image standardization based on fat and pectoral muscle signals was necessary for intercase comparisons. Multispectral images obtained based on this analysis suggest the feasibility of intensity-based image classification.

Light scanning versus mammography in breast cancer detection

Transillumination light scanning of the breast was compared with screen-film mammography in a prospective study of 1,110 women referred to an outpatient imaging department. Each method was interpreted independently of the other but with knowledge of physical examination findings. Of 24 biopsy-proved cancers, 14 (58%) were detected with light scanning and 21 (88%) with mammography. The 77 false-positive light scan examinations were attributed to technical factors and the inability of light scanning to distinguish malignant from benign conditions on the basis of imaging features. Of the ten false-negative light scan examinations, two were retrospectively reclassified as positive, but light scans in the other eight cases remained normal in appearance. The authors conclude that transillumination light scanning is not competitive with mammography as a screening method for breast cancer detection. furthermore, they were unable to identify a select subpopulation of women who might benefit from light scanning as an adjunct to mammography.

Carpal avascular necrosis: MR imaging

The authors evaluated the use of magnetic resonance (MR) imaging in diagnosis of avascular necrosis (AVN) of carpal bones by examining 21 patients with wrist pain and two healthy volunteers. MR images were compared with conventional radiographs in every case and with bone scintigrams in 18 cases. MR imaging was slightly less sensitive than bone scintigraphy in depicting AVN, but in patients who were imaged with long repetition time (TR)/long echo time (TE) sequences in addition to short TR/short TE sequences, MR imaging was found to be more specific. While the authors believe that bone scintigraphy remains the screening test of choice for patients with wrist pain and normal plain radiographs, MR imaging promises to add significant diagnostic information in cases in which bone scans are abnormal.

Soft-tissue tumors: MR imaging

We evaluated the suspected soft-tissue masses of 33 patients using magnetic resonance (MR) imaging. Thirty-two masses were defined, of which ten were malignant and 22 were benign. Specific characteristics that would allow us to distinguish the benign lesions from the malignant ones could not be identified on MR imaging. Lesions located within muscles or in the intramuscular septa were best seen with T2-weighted imaging sequences; those located within the subcutaneous fat were best outlined with T1-weighted imaging sequences. Both imaging sequences were necessary to provide the complete representation of the extent of the mass. We performed comparison studies using computed tomography (CT) in 24 of the cases. Of 92 possible comparisons and in four categories MR imaging yielded results that were superior to those obtained by CT scanning in 30 instances, equaled the results obtained by CT scanning in 62 instances, but never yielded results inferior to those obtained by CT scanning. However, MR imaging failed to demonstrate soft-tissue calcification and soft-tissue gas in one case each.