Glenoid notch MRI findings do not predict normal variants of the anterior and superior labrum

AIM

To determine (1) the relationship of a glenoid notch to the presence of a normal labral variant in the anterior-superior glenoid labrum; (2) the inter- and intra-observer reliability of recognising a glenoid notch; and (3) whether magnetic resonance arthrography (MRA) is more reliable than non-contrast magnetic resonance imaging (MRI) in visualising a glenoid notch.

MATERIALS AND METHODS

From 1995 through 2010, 104 patients underwent MRI or MRA before diagnostic shoulder arthroscopy by the senior author. Five blinded musculoskeletal radiologists independently read the images twice to evaluate for the presence or absence of a glenoid notch. Fifty-nine (57%) patients had normal anterior-superior labral variants. The authors calculated the relationship of the readings to the arthroscopically determined presence or absence of a normal labral variant and the reading's diagnostic performance and rater reliability.

RESULTS

On average, 38% (range 9-65%) of the glenoid scans were read as notched. The sensitivity, specificity, positive predictive value, and negative predictive value of the notch relative to the presence of a normal variant were 43.1%, 71.2%, 70.2%, and 48% versus 44.3%, 77.5%, 79.4%, and 56.1% for MRI and MRA, respectively. The overall average intra-observer κ-values were 0.438 (range 0.203-0.555) and 0.346 (range -0.102 to 0.570) for MRI and MRA, respectively. The average interobserver intra-class correlation coefficient reliability values were 0.730 (range 0.693-0.760) and 0.614 (range 0.566-0.662) for MRI and MRA, respectively.

CONCLUSIONS

A notched glenoid on MRI lacks sufficient diagnostic performance and rater reliability for the clinical detection and prediction of normal anterior-superior labral variants.

Complications of rotator cuff surgery-the role of post-operative imaging in patient care

When pain or disability occurs after rotator cuff surgery, post-operative imaging is frequently performed. Post-operative complications and expected post-operative imaging findings in the shoulder are presented, with a focus on MRI, MR arthrography (MRA) and CT arthrography. MR and CT techniques are available to reduce image degradation secondary to surgical distortions of native anatomy and implant-related artefacts and to define complications after rotator cuff surgery. A useful approach to image the shoulder after surgery is the standard radiography, followed by MRI/MRA for patients with low "metal presence" and CT for patients who have a higher metal presence. However, for the assessment of patients who have undergone surgery for rotator cuff injuries, imaging findings should always be correlated with the clinical presentation because post-operative imaging abnormalities do not necessarily correlate with symptoms.

Experimental model for cartilage tissue engineering to regenerate the zonal organization of articular cartilage

OBJECTIVE

Regeneration of the zonal organization of articular cartilage may be an important advancement for cartilage tissue engineering. The first goal of this study was to validate our surgical technique as a method to selectively isolate chondrocytes from different zones of bovine articular cartilage. The second goal was to confirm that chondrocytes from different zones would have different proliferative and metabolic activities in two-dimensional (2-D) and 3-D cultures. Finally, to regenerate the zonal organization, we sought to make multi-layered constructs by encapsulating chondrocytes from different zones of articular cartilage.

DESIGN

Cartilage slices were removed from three (upper, middle, and lower) zones of articular cartilage of young bovine legs. Histology and biochemical composition of the cartilage slices were analyzed to confirm that they had been obtained from the proper zone. Growth kinetics and gene expression in monolayer culture and matrix formation in photopolymerizing hydrogels were evaluated. Multi-layered photopolymerizing hydrogels were constructed with chondrocytes from each zone of native cartilage encapsulated. Cell viability and maintenance of the cells in the respective layer were evaluated using the Live/Dead Viability kit and cell tracking protocols, respectively. After 3 weeks, the multi-layered constructs were harvested for histologic examination including immunohistochemistry for type II collagen.

RESULTS

Analysis of histology and biochemical composition confirmed that the cartilage slices had been obtained from the specific zone. Chondrocytes from different zones differed in growth kinetics and gene expression in monolayer and in matrix synthesis in 3-D culture. Cells encapsulated in each of the three layers of the hydrogel remained viable and remained in the respective layer in which they were encapsulated. After 3-week culture, each zone of multi-layered constructs had similar histologic findings to that of native articular cartilage.

CONCLUSION

We present this as an experimental model to regenerate zonal organization of articular cartilage by encapsulating chondrocytes from different layers in multi-layered photopolymerizing gels.

[Results of repair of SLAP lesion]

The surgical repair of SLAP lesions has become increasingly more common as the techniques and instrumentation have improved. However, there are few studies examining the results of repair of SLAP lesions. The goals of this paper are to summarize the recommended treatment for SLAP lesions and to report upon the studies available to date which report the results of SLAP repair.

The anatomic relationship of the brachial plexus and axillary artery to the glenoid. Implications for anterior shoulder surgery

Iatrogenic brachial plexus injury is an uncommon but potentially severe complication of shoulder reconstruction for instability that involves dissection near the subscapularis muscle and potentially near the brachial plexus. We examined the relationship of the brachial plexus to the glenoid and the subscapularis muscle and evaluated the proximity of retractors used in anterior shoulder surgical procedures to the brachial plexus. Eight fresh-frozen cadaveric shoulders were exposed by a deltopectoral approach. The subscapularis muscle was split in the middle and dissected to reveal the capsule beneath it. The capsule was split at midline, and a Steinmann pin was placed in the equator of the glenoid rim under direct visualization. The distance from the glenoid rim to the brachial plexus was measured with calipers with the arm in 0 degrees, 60 degrees, and 90 degrees of abduction. The brachial plexus and axillary artery were within 2 cm of the glenoid rim, with the brachial plexus as close as 5 mm in some cases. There was no statistically significant change in the distance from the glenoid rim to the musculocutaneous nerve, axillary artery, medial cord, or posterior cord with the arm in various degrees of abduction. Retractors placed superficial to the subscapularis muscle or used along the scapular neck make contact with the brachial plexus in all positions tested.

Scapular and clavicular kinematics during humeral elevation: a study with cadavers

A combination of kinematic testing and graphic reconstruction of cadaveric shoulders was used to characterize shoulder kinematics during a simulated passive clinical range-of-motion examination. Cadaveric shoulders were elevated in the coronal, scapular, and sagittal planes while the scapula, clavicle, and humerus were kinematically tracked. Graphic models of each shoulder were created from computed tomography data. The models were animated to display the experimental motions. Shoulder kinematics varied between elevation planes. The scapular and clavicular rotations were relatively small until the humerus reached approximately 90 degrees of elevation. Clavicular and scapular rotations that occurred at low humeral elevation angles for elevation in the coronal plane were significantly larger than for the other two planes. The glenohumeral to scapulothoracic ratio was approximately equal to 2 for the entire range of elevation for each elevation plane, but it was dramatically larger during early elevation than during late elevation.

Spiral CT colonography: reader agreement and diagnostic performance with two- and three-dimensional image-display techniques

PURPOSE

To assess the diagnostic performance and reader agreement with two-dimensional (2D) and three-dimensional (3D) display techniques for detecting colorectal polyps with spiral computed tomographic (CT) colonography.

MATERIALS AND METHODS

A test set of 30 colonic segments was developed from spiral CT colonographic studies (12 with polyps and 18 without). The 12 segments with polyps contained 22 lesions (11 polyps <10 mm, 11 polyps or cancers >/=10 mm), with all findings verified with colonoscopy. Three specific 2D and 3D image-display techniques were tested. Three experienced abdominal radiologists independently analyzed each test case and were retested 6 weeks later.

RESULTS

The results of readings 1 and 2 were similar for all image-display techniques among the readers. Pooled segment results were sensitivity of 89%-92% and specificity of 72%-83%. Pooled polyp size results for sensitivity and positive predictive value were 77%-86% and 74%-86% (all polyps, n = 22), 91%-100% and 85%-100% (polyps or cancers >10 mm, n = 11), and 61%-73% and 61%-80% (polyps 5-9 mm, n = 11), respectively. Overall intraobserver agreement was good for the three display techniques (kappa, 0.60-1.00); however, interobserver agreement for 2D multiplanar reformation was lower (kappa, 0.53-0.80).

CONCLUSION

Among experienced abdominal radiologists, similar diagnostic performance in polyp detection was found among 2D multiplanar reformation and 3D display techniques, although individual cases showed improved characterization with 3D display techniques. Evaluation of reader agreement demonstrated good intraobserver agreement, with variable interobserver agreement.

Clinical significance of the arthroscopic drive-through sign in shoulder surgery

PURPOSE

During arthroscopy of the shoulder, the ability to pass the arthroscope easily between the humeral head and the glenoid at the level of the anterior band of the inferior glenohumeral ligament is considered a positive drive-through sign. The drive-through sign has been considered diagnostic of shoulder instability and has been associated with shoulder laxity and with SLAP lesions. The goal of this study was to examine the prevalence of the drive-through sign in patients undergoing shoulder arthroscopy and to determine its relationship to shoulder instability, shoulder laxity, and to SLAP lesions.

TYPE OF STUDY

Case series.

METHODS

We prospectively studied 339 patients undergoing arthroscopy of the shoulder for a variety of diagnosis from 1992 to 1998. The drive-through sign was performed with the patients in a lateral decubitus position and under general anesthesia. The drive-through sign was correlated with preoperative physical findings, intraoperative laxity testing, and with intra-articular pathology at the time of arthroscopy.

RESULTS

The arthroscopic evaluation showed that drive-through sign was positive in 234 (69%) shoulders. For the diagnosis of instability, the drive-through sign had a sensitivity of 92%, a specificity of 37. 6%, a positive predictive value of 29.9%, a negative predictive value of 94.2%, and an overall accuracy of 49%. There was an association between the drive-through sign and increasing shoulder laxity, but not with SLAP lesions.

CONCLUSIONS

This study shows that a positive drive-through sign is not specific for shoulder instability but is associated with shoulder laxity. This arthroscopic sign should be incorporated with other factors when considering the diagnosis of instability.

The evolution of velopharyngeal imaging

Currently, functional visualization of the velopharynx requires tests that are either invasive (endoscopy) or that impart ionizing radiation (speech videofluoroscopy). The overall intrusiveness of endoscopy may limit its clinical utility, especially in young children. As a resut of growing awareness of the long-range effects of radiation exposure associated with X-ray imaging, radiographic research on subjects and studies not judged to be clinically necessary have been all but abandoned. The static nature of lateral radiographs precludes temporal assessment, and the two dimensionally of images derived from both of these diagnostic modalities may limit understanding of spatial anatomic relationships and may preclude quantitative analysis. The need for a noninvasive, rapid, and easily repeatable method for examination of the velopharynx has fomented the innovative application of existing technologies, especially magnetic resonance imaging. We present an updated overview of techniques for imaging the velopharyngeal mechanism, with a focus on residual velopharyngeal dysfunction after initial palatoplasty. We provide a comprehensive perspective of the role of currently available instrumentation, summarize the work in our center regarding the technological developments of magnetic resonance imaging, and speculate about future applications of magnetic resonance imaging systems for evaluation of velopharyngeal dysfunction. The limitations of each of these measures discussed are emphasized.

Shoulder instability in the athlete

Shoulder instability is a common malady affecting the athlete's shoulder. A basic knowledge of shoulder anatomy and biomechanics is essential to understanding the pathophysiology and treatment options. The history and physical examination can lead the investigator to the correct diagnosis in most cases. Diagnostic imaging modalities can provide useful clues and help rule out concomitant pathology. Most patients are suitable candidates for a trial of shoulder rehabilitation. Those who fail nonoperative treatment may be candidates for surgical intervention. A variety of surgical techniques are available to reliably prevent recurrent instability. There has been a recent trend towards arthroscopic stabilization, including thermal capsulorrhaphy, which may prove as effective as open techniques.

New imaging techniques for the evaluation of gastrointestinal diseases

This article provides an overview of recently developed, noninvasive imaging modalities for the evaluation of gastrointestinal disease processes. The advent of spiral computed tomography, magnetic resonance cholangiopancreatography and conventional magnetic resonance imaging has facilitated the noninvasive assessment of pancreaticobiliary disease. Magnetic resonance cholangiopancreatography provides projectional images of the biliary tree and pancreatic duct, similar to those achieved by direct cholangiography, without the need to administer contrast medium. Spiral computed tomographic colonography provides virtual colonoscopic images of the colonic mucosa, allowing the detection of polyps without the risk associated with colonoscopy.

Synovial chondromatosis of the shoulder associated with osteoarthritis: conservative treatment in two cases and review of the literature

Periarticular synovial chondromatosis associated with osteoarthrosis is a rare condition that is more frequently seen in the lower extremity than in the upper extremity. In patients who have synovial chondromatosis of the joints of the lower extremity and are symptomatic, the traditional method of treatment has included open or arthroscopic synovectomy and removal of loose bodies. In cases involving the upper extremity, especially in the shoulder, patients have variable disability and may be treated successfully without surgery. Two patients who presented to our practice with shoulder symptoms due to synovial chondromatosis were treated successfully without surgery. In both patients nonoperative treatment consisting of activity modification, nonsteroidal anti-inflammatory medication, and cryotherapy as needed led to a good result without surgical intervention.

Influence of image acquisition parameters on CT artifacts and polyp depiction in spiral CT colonography: in vitro evaluation

PURPOSE

To quantify the effects of spiral computed tomographic (CT) acquisition parameters on the magnitude of three-dimensional (3D) rippling artifacts and polyp depiction.

MATERIALS AND METHODS

An in vitro colon phantom was constructed with air-filled acrylic cylinders that contained synthetic polyps of 3-13 mm. The phantom was submerged in fluid and positioned at four angles of inclination relative to the z axis. Image data were acquired at collimation and pitch combinations of 3 mm and 1.67 and 5 mm and 1.6, respectively. Rippling artifacts were quantified by measuring the longitudinal variation of in-plane phantom edge width, and the influence of these artifacts on the depiction of pedunculated and sessile polyps was assessed qualitatively.

RESULTS

The in-plane magnitude of the rippling artifact was a function of the angle of inclination relative to the longitudinal axis and the table increment. The through-plane periodicity of the artifact was equal to one-half the table increment.

CONCLUSION

The table increment and angle of inclination of the surface of the object relative to the z axis determine the periodicity and magnitude of the rippling artifact at 3D spiral CT colonography. Although the depiction of small pedunculated polyps was not compromised, some sessile polyps were degraded by the artifact.

[Superior labrum pathology in the athlete]

Since their first description several years ago, superior glenoid labral lesions have increasingly been blamed for shoulder problems associated with sports. Originally merely describing arthroscopically visible upper labral/biceps abnormalities, the current understanding is that often clinical problems such as impingement pain or even rotator cuff disease can be secondary to these lesions, especially in overhead athletes. Impingement in these cases is caused by superior shoulder instability originating from an unstable biceps insertion that is present for example in SLAP (superior labrum from anterior to posterior) lesions. Additional problems such as internal or posterosuperior impingement that are often found simultaneously in these patients are pathomorphologically located in the same anatomical region and therefore make exact diagnosis and thus treatment more complex. Magnetic resonance imaging with intra-articular contrast enhancement and particularly arthroscopy are the primary tools for exact diagnosis and classification of superior labral/biceps pathology. Therapeutically, lesions with unstable biceps origin (SLAP types 2 and 4) require operative refixation, as we have seen in our 50 cases in the last 4 years, in order to reestablish the stabilising effect of the biceps tendon for the shoulder joint. The arthroscopic technique for repair of these lesions using different devices of implantable suture anchors is presented. Long-term pain-free shoulder function in competitive athletes, throwers in particular, thus requires anatomical reconstruction of the originally unstable biceps, which is the causal therapy for these lesions.

A prospective assessment of breath-hold fast spin echo and inversion recovery fast spin echo techniques for detection and characterization of focal hepatic lesions

The purpose of this study was to prospectively assess two breath-hold T(2)-weighted fast spin-echo sequences and two breath-hold inversion recovery fast spin-echo sequences to determine their relative ability to detect and characterize focal hepatic lesions. Fourteen patients with a total of nineteen proven focal hepatic lesions were imaged with two breath-hold T(2)-weighted (T2W) fast spin echo sequences (HASTE TE = 66 and HASTE TE = 120), two breath-hold inversion recovery fast spin echo sequences (IRFSE TE = 64 and IRFSE TE = 95), and a nonbreath-hold T(2)-weighted fast-spin echo sequence (FSE TE = 96-120). Contrast-to-noise ratios (CNRs) were measured for all proven lesions on all sequences. Both IRFSE sequences and the HASTE sequence with TE = 66 showed an improvement in lesion-liver and liver-spleen CNRs compared to the nonbreath-hold T2W sequence. The mean difference in CNR between benign and malignant lesions was largest for the HASTE TE = 120 sequence. These preliminary results suggest that a breath-hold IRFSE sequence (TE = 64 or 95) has an equal ability to detect focal hepatic lesions as a nonbreath-hold T2W FSE sequence (TE = 96-120). The HASTE TE = 120 showed the greatest ability to discriminate between benign and malignant lesions.

Olecranon and prepatellar bursitis: treating acute, chronic, and inflamed

Elbow and knee bursitis is common in both athletes and nonathletes and has three basic presentations: acute, chronic nonseptic, and chronic infected. Most acute swellings occur after trauma and can be treated with early aspiration, compression, and padding. Chronic, nonseptic bursitis can usually be treated with conservative therapy and, occasionally, aspiration or corticosteroid injection. Inflamed bursae should be aggressively evaluated and treated. Some may require aspiration and decompression, and oral or intravenous antibiotics should be started to prevent septicemia. Incision and drainage is rarely needed but may be indicated for injuries that do not respond. Surgical excision of the bursa is recommended only for recalcitrant cases.

Fast algorithm for soft straightening of the colon

RATIONALE AND OBJECTIVES

In this study, the authors developed a fast algorithm for soft straightening of the colon with computed tomographic data that greatly accelerates the unraveling process based on the interpolation of representative electric force lines.

MATERIALS AND METHODS

Each curved cross section of the colon is defined by electric force lines of a common origin on an electrically charged central path and is constructed by interpolating most of these force lines from a limited number of representative force lines that are traced directly. Both a synthetic colon phantom and a colon in a living patient were used to demonstrate the feasibility of the fast interpolation algorithm compared with direct implementation for soft straightening of the colon.

RESULTS

The interpolation-based soft-straightening algorithm ran approximately 40 times faster than the direct implementation of the electric field-based soft-straightening algorithm.

CONCLUSION

The fast algorithm for soft straightening of the colon has potential for use in computed tomographic colonography.

Optimal section spacing in single-detector helical CT

To define the section spacing that maximizes longitudinal resolution without needless section overlap, the optimal percentage of overlap was computed theoretically and expressed as a constant relative to the effective section thickness. For imaging applications that require maximal longitudinal resolution, single-detector helical computed tomographic images should be reconstructed with at least 60% overlap relative to the effective section thickness.

The value of weighted views of the acromioclavicular joint. Results of a survey

One hundred twelve practicing members of the American Shoulder and Elbow Surgeons in the United States and Canada were surveyed regarding use of weighted views of the acromioclavicular joint. They were also asked about treatment for hypothetical patients seen in the emergency department or office with grade II or III acromioclavicular separations. One hundred five physicians (94%) responded to the survey. Eighty-five members (81 %) did not recommend obtaining weighted views in the emergency department. Sixty members (57%) did not use weighted views, and the majority commented that weighted views had no influence on their decision-making regarding treatment. Forty-five members (43%) used weighted views, but most did not use the results of this test to determine surgical intervention. Physicians recommending weighted views averaged 21 years of practice, compared with 16 years for those who did not obtain weighted views. Only nine physicians (9%) had changed treatment on the basis of weighted views. The patient's arm dominance, work, or athletic status did not influence most surgeons' decision to perform surgery when weighted views revealed a grade III separation. We found no correlation between obtaining weighted views and performing surgical reconstruction for patients with grade III acromioclavicular separations.

Internal impingement of the shoulder: a clinical and arthroscopic analysis

Internal impingement was first described by Walch in 1992 and defined as contact between the supraspinatus tendon and posterior-superior glenoid rim with the shoulder in the cocked, throwing position of 90 degrees of abduction and maximum external rotation. The hypothesis of the study was that this contact may be seen in patients who are not throwing athletes nor in those who have instability. One hundred five consecutive patients who underwent shoulder arthroscopy were prospectively studied with preoperative history and physical examination. All patients underwent general anesthesia and arthroscopy with a standard posterior portal. With the patient under arthroscopy the arm was placed in abduction and external rotation until contact was made or until full elevation was reached. Eighty-five percent (N = 90) of the patients made contact between the rotator cuff and glenoid rim at an average of 95 degrees of abduction and 74 degrees of external rotation. No statistically significant relationship was seen (P > .05) between the position of contact at internal impingement and mechanism of injury, throwing versus nonthrowing, instability, rotator cuff tear, preoperative external rotation, or preoperative impingement signs. The intraoperative finding of contact of the rotator cuff to the posterosuperior glenoid with the arm in abduction and external rotation can occur in a wide spectrum of shoulder disease and is not limited to the throwing athlete. Not all patients with increased laxity and instability demonstrate this contact, suggesting that these factors may not be essential for internal impingement.

Joint surgery in Ehlers-Danlos patients: results of a survey

The Ehlers-Danlos syndrome (EDS) is a rare, hereditary, connective-tissue disorder that results in increased laxity and poor soft-tissue healing. Surgical results and complications in these patients are not well documented in the literature. The goal of the present study was to survey patients with EDS who had surgery to the musculoskeletal system and document the results of surgery and complications. Forty-four patients with EDS were surveyed regarding the complications and results of surgical procedures to the shoulder, the elbow, the knee, or the ankle. Surgical procedures were performed for pain, instability, poor range of motion, or a combination of these, totaling 214 procedures. The population surveyed in the present study demonstrates that problems of surgical procedures in EDS may be high relative to other populations without connective-tissue disorders. More study is warranted in this patient population to validate the results in a larger cohort.

Occult presentation of myotonia congenita in a 15-year-old athlete

A case of myotonia congenita in an adolescent athlete was presented. Although this is a rare condition unknown to many treating physicians, the key to diagnosis was provocation of the patient's symptoms of muscle "tightening" and "cramping" during sustained exercise. The diagnosis would have been missed in routine office examinations with the patient at rest. The stereotypic generalized myotonic signs and symptoms were provoked after the patient was asked to play 20 minutes of basketball during one of his office evaluations. The provocative or postexercise examination was critical to the diagnosis as the resting office examination was completely normal. The diagnosis was subsequently confirmed by EMG and genetic testing. Myotonia congenita should be considered in the differential diagnosis of athletes with exercise-induced muscle "stiffness" or "cramping," particularly if the course is protracted and initial examinations are unremarkable. A provocative exercise period can be used to make the diagnosis. Once the diagnosis is established, appropriate pharmacologic treatment may improve symptoms and allow return to daily activity without restriction.

Straightening the colon with curved cross sections: an approach to CT colonography

RATIONALE AND OBJECTIVES

The purpose of this study was to straighten digitally and consistently the colon with curved cross sections and to compare the results with planar cross-section-based processing for computed tomographic (CT) colonography.

MATERIALS AND METHODS

In electric field-based straightening, curved cross sections are formed along electric force lines because of electric charges digitally distributed along the colon central path. Four straightening experiments were conducted on CT scans of a colonoscopy phantom. Representative images were studied for polyp detectability and feature distortion. Two further trials involved patient data to demonstrate the clinical feasibility of this method.

RESULTS

In colon straightening with planar sections, a polyp was counted multiple times in both phantom and patient studies where the polyps were in central path turns with substantial curvature. Furthermore, opposite the central path turns, the colon walls were undersampled with planar sections. Straightening with curved sections produced consistent mappings. Image distortion was present in straightening with curved sections, but the conspicuity of polyps was maintained. In the soft-straightening process, trilinear interpolation greatly suppressed the surface- or volume-rendering noise associated with nearest neighbor interpolation.

CONCLUSION

Straightening with curved sections outperforms straightening with planar sections in terms of polyp detectability. This approach eliminates the navigation difficulties of current CT colonography and may have clinical use.

The deceptive nature of clavicle fractures in young patients

A shoulder injury that would cause an acromioclavicular (AC) separation in an adult generally causes a clavicle fracture in a young patient. As illustrated in a case report, the two injuries can look similar on a standard x-ray. Conservative treatment and prognosis for both clavicle fractures and AC separations are similar, but because some AC separations require surgical repair, accurate diagnosis is important. This can be done by obtaining x-rays at one-half of the standard exposure, including AP views with 10 degrees to 15 degrees of cephalic tilt. Spot or cone-down views and comparison views are also helpful.

Condensing osteitis of the clavicle: case report and review of the literature

Osteitis condensans of the clavicle is a rare condition characterized by pain in the shoulder and often limitation of motion of the shoulder. The medical history and results of the physical examination, laboratory data, and radiographic studies (including computed tomography and magnetic resonance imaging), often establish the diagnosis. Patients who have slight or no pain usually require no treatment. Varying results have been reported for many different methods of treatment, including surgical excision, chemotherapy, antibiotics, nonsteroidal anti-inflammatory medications, radiation, local corticosteroid injection, and physical therapy. A typical case report and the differential diagnosis for condensing osteitis of the clavicle are presented.

Hepatic T2-weighted MRI: a prospective comparison of sequences, including breath-hold, half-Fourier turbo spin echo (HASTE)

The purpose of this study was to quantitatively compare the hepatic contrast characteristics of conventional spin-echo (CSE) and fast spin-echo (FSE) sequences with breath-hold T2-weighted images acquired with half-Fourier turbo spin echo (HASTE). Forty-five patients were examined with a phased-array surface coil. Nineteen patients had focal hepatic lesions, including eight malignant tumors, 10 cavernous hemangiomas, and one hepatic adenoma. Twenty-six patients had no focal hepatic lesions. T2-weighted images with comparable TE were acquired with CSE, FSE, and HASTE pulse sequences. Signal-to-noise ratio (SNR) and contrast-to-noise ratio (CNR) for liver, spleen, and lesions were measured. FSE demonstrated significantly better quantitative performance than CSE for liver-spleen CNR (P .0084). No statistically significant difference was demonstrated between FSE and CSE for liver or spleen SNR. FSE demonstrated clear scan time and resolution advantages over CSE. HASTE performed significantly poorer than CSE and FSE for liver-spleen CNR (P < .0001), liver SNR (P = .0002 for CSE and P < .0001 for FSE), and spleen SNR (P < .0001). Optimized FSE images with a short echo train length performed comparably to CSE images of equivalent TE. Liver-lesion CNR was suppressed on HASTE images, suggesting that long echo train length FSE sequences could diminish solid lesion detection compared to CSE and short echo train length FSE.

The deltoid muscle origin. Histologic characteristics and effects of subacromial decompression

The histologic characteristics of the deltoid muscle attachment to nine cadaveric acromia were studied using light microscopy. The deltoid muscle attaches to the anterior and lateral acromion primarily by direct tendinous attachment. The muscle attaches to the dorsal side of the acromion by periosteal fiber attachment. In the specimens studied, a hypothetical acromioplasty of 4 mm would release, on average, 41% of the direct fiber attachment, and a 6-mm acromioplasty would release 69% for all zones examined histologically. The functional and clinical effects of these findings are not known, but the deltoid muscle would be released by arthroscopic acromioplasty in areas where bone is removed.

GI tract unraveling with curved cross sections

Gastrointestinal (GI) tract examination with spiral/helical computed tomography (CT) is currently performed by slice-based inspection of axial images. CT colography is a recent advance which allows an intraluminal visualization of the colon, similar to endoscopy. Various rendering algorithms have been developed with promising results, however navigation through the complex, tortuous anatomy of the colon can be time consuming in practice. In this paper, we propose an electrical-field-based method to unravel the convoluted colon, that is, to digitally straighten it with curved cross sections and flatten it over a plane. In our method, electrical charges are simulated along the central colon path. Curved cross sections are defined by the electrical force lines, and lead to consistent unraveling. It is demonstrated with image volumes of two patients that this technique produces a global planar view of complicated colon features with a potential for detection of polyps.

Pancreatic enhancement and pulse sequence analysis using low-dose mangafodipir trisodium

OBJECTIVE

The purpose of this study was to evaluate pancreatic enhancement with low-dose mangafodipir trisodium (5 mumol/kg) using three different T1-weighted pulse sequences.

SUBJECTS AND METHODS

Fifteen patients, six of whom had proven focal pancreatic tumors, underwent T1-weighted gradient-recalled echo imaging, spin-echo imaging, and fat-suppressed spin-echo imaging before and 30 min after injection of 5 mumol/kg of mangafodipir trisodium. Region-of-interest measurements were obtained in the pancreas before and after contrast enhancement. Signal-to-noise ratios were calculated in all 15 patients. Contrast-to-noise ratios were calculated in the six patients with pancreatic tumors.

RESULTS

The signal-to-noise ratios of the pancreas increased after injection of mangafodipir trisodium on all three T1-weighted pulse sequences (p < .001). Enhanced fat-suppressed sequences (29 +/- 7.7) and gradient-recalled echo sequences (29 +/- 9.6) had the highest signal-to-noise ratios. Contrast-to-noise ratios between normal pancreatic tissue and pancreatic tumor also increased after contrast administration (p < .05) and were highest on the fat-suppressed (-9.6 +/- 4.0) pulse sequence.

CONCLUSION

Mangafodipir trisodium produced marked pancreatic enhancement at a dose of 5 mumol/kg for all three T1-weighted pulse sequences. The enhanced T1-weighted spin-echo fat-suppressed sequence showed the highest signal-to-noise and contrast-to-noise ratios.

Epidemiology of collegiate baseball injuries

OBJECTIVE

We sought to establish injury incidence, onset, location, type, and severity for a collegiate baseball team. The second objective was to compare the number of musculoskeletal problems for which baseball players sought treatment with those that resulted in time lost or modified participation.

METHODS

This was a prospective, epidemiologic study. A complaint was defined as any evaluation by a player to the medical staff that required either evaluation or treatment. An injury was defined as any complaint that resulted in altered participation or time lost from practice or game participation. Participants were Division I collegiate baseball team with one athletic trainer and one academic sports medicine specialist. All members of the collegiate baseball team were studied over a 3-year period to determine the overall incidence of injury per 1,000 exposures (A-E) to practice or participation, injuries sustained over 3 years by collegiate baseball players.

RESULTS

Overall there were 277 complaints and 52 injuries (19%). The A-E rate was 5.83. Forty-six percent of the injuries occurred in practice and 54% in games. Seventy-three percent of the injuries resulted in < 7 days lost from sport, and 25% resulted in > 21 days lost participation. The most common origin of injury was strains (23%), sprains (19%), and contusions (17%). Fifty-eight percent of the injuries were to the upper extremity, 15% to the trunk/back, and 27% to a lower extremity. Upper extremity injuries accounted for 75% of the total time lost from the sport. When divided by position, the shoulder injuries occurred in pitchers (69%), infielders (19%), and outfielders (12%). Rotator cuff tendinitis was the most frequent complaint, was the most frequent injury, and resulted in the most time lost from the sport.

CONCLUSIONS

Defining injury as time lost or as altered participation underestimates the frequency with which players seek evaluation and treatment. Injuries are divided widely across anatomic site, but upper extremity injuries cause the most time lost from the sport. Further study of the origin and prevention of upper extremity injuries in baseball is warranted.

Characteristic ground-reaction forces in baseball pitching

Overhand throwing requires contributions from and interaction between all limb segments. Most previous investigations have concentrated on the throwing arm itself, yet poor mechanics at the arm may originate in the lower extremities. Multicomponent ground-reaction forces of both the push-off and landing limbs were measured in six collegiate and one high school level baseball pitchers. Full body kinematics were simultaneously recorded to correlate phases in the pitching cycle with the force data. Pitchers were found to generate shear forces of 0.35 body weight in the direction of the pitch with the push-off leg and to resist forces of 0.72 body weight with the landing leg. Wrist velocity was found to correlate highly with increased leg drive. This study validates the clinical impression that the lower extremity is an important contributor to the throwing motion. Based on this study, strengthening of the lower extremities could be inferred to be important both to enhance performance and to avoid injury.

Visualization of colorectal polyps with spiral CT colography: evaluation of processing parameters with perspective volume rendering

PURPOSE

To evaluate two key processing steps for detection of colon polyps with spiral computed tomographic (CT) colography with perspective volume rendering (PVR): image reconstruction and opacity assignment of the attenuation data.

MATERIALS AND METHODS

Spiral CT was performed in 10 patients with known polyps confirmed at colonoscopy, and detailed quantitative analyses were performed of data obtained in four. First, anatomic fidelity of three-dimensional (3D) images generated from two-dimensional (2D) source images with equal voxel dimensions (87%-90% overlap) was compared with 3D images generated from 2D source images with unequal voxel dimensions (0%-80% overlap). Next, the relative dimensions of colorectal polyps to adjacent structures were evaluated for various opacity threshold settings. Then, step and sigmoidal opacity functions were compared with respect to image smoothness and edge sharpness.

RESULTS

PVR images generated after interpolation of image data reconstructed with at least 60% overlap were equivalent in image quality to PVR images generated from source images with equal voxel dimensions. Relative polyp-to-haustral fold dimensions demonstrated substantial distortions with opacity thresholds below -700 HU. The 3D PVR images generated with the sigmoidal opacity function were significantly smoother than those generated with the step opacity function (paired t test, P < .02), with small differences noted in edge sharpness.

CONCLUSION

Use of highly overlapping source images (87%-90%) was not necessary to generate 3D PVR images of colorectal polyps. Image artifacts were suppressed with use of an appropriate opacity threshold and a sigmoidal opacity function without substantial loss in edge sharpness.

Reliability of radiographic evaluation for acromial morphology

OBJECTIVE

Bigliani's classification system of acromial morphology utilizing the standard outlet radiograph has become in accepted method for evaluating patients with rotator cuff disease. This study evaluates the interobserver and intraobserver reliability of Bigliani's classification system using observers at various levels of training.

PATIENTS AND DESIGN

Supraspinatus outlet view radiographs of 40 patients (aged 18-78 years) with shoulder pain were reviewed twice, 4 months apart, in a masked protocol by six reviewers, including two attending (fellowship-trained) shoulder surgeons, an attending musculoskeletal radiologist, an orthopedic surgery sports fellow, and two orthopedic residents (PGY-2 and PGY-5). The reviewers were given standard diagrams of the Bigliani classification system and were asked to classify each film as a type I, II, or III acromion. Interobserver reliability and intraobserver repeatability values were calculated using kappa statistic analysis (0-0.2 slight, 0.21-0.4 fair, 0.41-0.6 moderate, 0.61-0.8 substantial, and 0.8-1.0 excellent).

RESULTS AND CONCLUSION

For each of the two readings, all six observers agreed only 18% of the time. Kappa values for pairwise comparison of interobserver reliability among the six observers ranged from 0.01 to 0.75 (mean 0.35), and intraobserver repeatability ranged from 0.26 (PGY-5 resident) to 0.80 (fellowship-trained surgeon), with a mean of 0.55. Intraobserver repeatability was not significantly different for the different levels of expertise. More definitive criteria are needed to distinguish and classify the acromion.

Shoulder immobilization devices

Currently a myriad of devices are available for immobilization of the injured or postsurgical upper extremity. Some of these devices are straightforward and easily used, but some are more complicated and require more familiarity for their successful application. However, even simple devices have the potential for misapplication and thus prevent their benefit to the patient. This article is the third in a 3-part series. The goals of the series are (1) to present and review several devices on the market used by shoulder surgeons to immobilize the upper extremity, and (2) to discuss proper application and precautions of their use. It is intended that this series will benefit nurses, therapists, and trainers involved in the use of these devices.