Prevalence of HAGL lesions and associated abnormalities on shoulder MR examination

Objective

Humeral avulsion of the glenohumeral ligament (HAGL) is an uncommon shoulder injury. We report the prevalence of HAGL lesions and other associated shoulder injuries in a large series of shoulder MR examinations. All results were correlated with surgery.

Materials and methods

MR reports of 1,000 consecutive conventional shoulder MR exams performed on patients with shoulder pain were reviewed in our information system for the word HAGL. A total of 743 patients went on to surgery. There were 23 HAGL lesions reported at surgery. Those 23 examinations were reviewed retrospectively in consensus by two musculoskeletal radiologists. Scans were assessed for HAGL lesions, full or partial thickness supraspinatus, infraspinatus or subscapularis tendon tears, superior labral anterior posterior (SLAP) tears, anterior or posterior labral tears, and Hill–Sachs lesions.

Results

All 23 patients had HAGL lesions at surgery. Sixteen HAGL lesions were seen on prospective MR reading and 17 HAGL lesions were seen on retrospective MR consensus reading. Six HAGL lesions were not seen on retrospective consensus reading. Sixteen patients had Hill–Sachs deformities, ten had subscapularis tendon tears, five had supraspinatus tendon tears, six had superior labral tearing, and six had anterior labral tears. The above findings were confirmed on arthroscopy.

Conclusions

In this series, there was a 1.6 % prevalence on all MR examinations, and prevalence of 2.1 % seen on MR examination for those who went to surgery. Common injuries associated with HAGL lesions are Hill–Sachs deformities and subscapularis tendon tears. Anterior labral tears were seen in only six cases despite Hill–Sachs deformities in 16 patients. In patients with Hill–Sachs deformities without anterior labral tears, one must carefully assess for the presence of a HAGL lesion.     

Association of biceps tendon tears with rotator cuff abnormalities: degree of correlation with tears of the anterior and superior portions of the rotator cuff

OBJECTIVE: This study was performed to examine the relationship and association of abnormalities seen in the long head of the biceps brachii tendon to abnormal findings in the rotator cuff. MATERIALS AND METHODS: One hundred eleven patients underwent MR imaging for shoulder pain followed by arthroscopic or open shoulder surgery from January 1997 to December 2000. Patients were identified by a retrospective search, and all consecutive patients having undergone both MR imaging and surgery were included in the patient cohort. Official MR imaging interpretations were compared with operative reports, and all findings were recorded. RESULTS: Twenty-three patients were identified with partial- or full-thickness tears of the long head of the biceps tendon. The sensitivity, specificity, and accuracy of unenhanced MR imaging of the shoulder for detecting these bicipital tears were 52%, 86%, and 79%, respectively. When a tear was present in the biceps tendon, the prevalence of supraspinatous, infraspinatus, and subscapularis tendon tears was 96.2%, 34.6%, and 47.1%, respectively. Patients with biceps tendon tears were significantly more likely to also have subscapularis tendon tears (p < 0.0001) and supraspinatous tendon tears (p < 0.008) than those patients who did not have biceps tendon tears. No significant relationship was found between the presence or absence of a biceps tendon tear and the presence or absence of a infraspinatus or teres minor tendon tear (p = 0.17). CONCLUSION: Tears of the long head of the biceps tendon have a statistically significant association with tears of the anterior and superior rotator cuff and are highly correlated with tears of the supraspinatous and subscapularis tendons. When tears of these tendons are detected, specific attention directed toward the long biceps tendon is warranted to characterize the status of this structure that provides additional stability to the shoulder joint.     

MR imaging of the knee. Part I. Traumatic disorders

One hundred thirty patients with a diversity of knee joint injuries were evaluated with a high-resolution magnetic resonance (MR) imaging technique. The authors report the accuracy of this technique in the evaluation of 105 patients with suspected meniscal tears, 26 patients with suspected cruciate ligament tears, and eight patients with suspected patellar tendon injuries. Of those menisci rated as definitely or probably torn on MR imaging, 80% were found to be torn at subsequent arthroscopy. The predictive value of negative MR imaging results was 100%. MR imaging was 92% accurate in predicting the clinical outcome in patients with suspected meniscal tears who did not undergo surgery. MR permitted complete disruption of the patellar tendon to be differentiated from partial tears, ligamentous inflammation, and localized effusion of the infrapatellar bursa. Injuries to the anterior and posterior cruciate ligaments were identified on MR images, and the status of synthetic grafts of the anterior cruciate ligament was ascertained.     

MR evaluation of subscapularis tears.

PURPOSE: The purpose of this work was to describe the MR appearance of tears of the subscapularis tendon and compare the usefulness of different imaging planes as well as note the association of subscapularis tears with other rotator cuff tears and biceps tendon dislocations. METHOD: MR studies at 1.5 T over an 8 year interval were retrospectively assessed for the presence of a rotator cuff tear and/or tear of the subscapularis tendon. Images that showed a subscapularis tear were reviewed for the presence of a visible tear separately on the axial, coronal, and sagittal images. The MR studies were also evaluated for associated tears of the supraspinatus, infraspinatus, and teres minor muscles as well as biceps tendon dislocation and the "naked humerus sign" on coronal images. Last, clinical records and surgical reports were reviewed. RESULTS: Forty-five (2%) of 2,167 rotator cuff tears involved the subscapularis; 27% were partial and 73% were complete tears. Tears were best seen in the sagittal oblique plane. Almost all subscapularis tears were an extension of typical rotator cuff tears: supraspinatus in 35 patients (79%), extending into infraspinatus tears in 25 (56%) and into teres minor tears in 2 patients (4%). Bicipital dislocations were seen in 22 patients (49%), and three complete tears of the biceps (7%) were noted as well. The naked humerus sign was demonstrated in 31 patients (69%). Surgical reports that confirmed the MR findings were available for 15 patients. CONCLUSION: About 2% of rotator cuff tears involve the subscapularis tendon. Most subscapularis tears are extensions of supraspinatus tears and frequently involve the biceps tendon.     

Helical CT of diaphragmatic rupture caused by blunt trauma

OBJECTIVE: The purpose of this study was to determine the diagnostic sensitivity and specificity of helical CT with sagittal and coronal reformatted images in detecting diaphragmatic rupture after blunt trauma. MATERIALS AND METHODS: Chest and abdominal helical CT scans obtained in 41 patients with suspected diaphragmatic injury after major blunt trauma were reviewed by three observers who were unaware of surgical findings. Coronal and sagittal reformatted images were reviewed for each patient as well. Findings consistent with diaphragmatic injury, such as waistlike constriction of abdominal viscera (i.e., the "collar sign"), intrathoracic herniation of abdominal contents, and diaphragmatic discontinuity were recorded. Sensitivity and specificity of helical CT were calculated on the basis of surgical findings and clinical follow-up. RESULTS: Helical CT was performed preoperatively in 23 patients with diaphragmatic rupture (left, n = 17; right, n = 5; bilateral, n = 1). An additional 18 patients underwent helical CT to further evaluate suspicious findings seen on chest radiography at admission and were found to have an intact diaphragm. Sensitivity for detecting left-sided diaphragmatic rupture was 78% and specificity was 100%. Sensitivity for the detection of right-sided diaphragmatic rupture was 50% and specificity was 100%. The most common CT finding of diaphragmatic rupture was the collar sign, identified in 15 patients (sensitivity, 63%; specificity, 100%). Diaphragmatic discontinuity was seen in four patients. CONCLUSION: Helical CT, especially with the aid of reformatted images, is useful in the diagnosis of acute diaphragmatic rupture after blunt trauma. Helical CT can be used to detect 78% of left-sided and 50% of right-sided injuries.     

Intraparenchymal brain metastases: MR imaging versus contrast-enhanced CT

Prospective and retrospective studies of 75 patients were performed to assess the sensitivities of magnetic resonance (MR) imaging and computed tomography (CT) in the evaluation of suspected intraparenchymal brain metastases. The findings on MR images were equivalent to those on CT scans in 49 of the 75 patients; the remaining findings were discordant in 26 patients, and neither MR imaging nor CT was consistently superior. MR imaging demonstrated more metastases in nine of these 26 patients. However, contrast material-enhanced CT scans were superior in lesion depiction in eight of the 26 patients. Large enhanced lesions that were nearly isointense on MR images were seen well on CT scans. In several cases in which results were discordant, gadolinium-diethylenetriaminepentaacetic acid (DTPA)-enhanced MR images were obtained, and this agent behaved similarly to iodinated contrast agents. If indicated clinically, such as before surgery for a single metastasis, the authors perform both MR imaging and contrast-enhanced CT. Gd-DTPA-enhanced MR imaging may prove to be the method of choice for depiction of intraparenchymal metastases.     

The value of CT in the detection of bladder and posterior urethral injuries

To determine the value of CT in the diagnosis of bladder and posterior urethral injuries, we retrospectively evaluated the CT and urethrocystographic findings in 33 trauma patients with suspected injuries of the lower urinary tract who had both studies in their initial evaluation. In 26 (79%) of 33 patients, results of both examinations were normal. Seven (21%) of 33 patients had bladder injuries (seven--two in one patient) and/or posterior urethral injuries (three) as determined on the basis of urethrocystography. Three patients had extraperitoneal bladder tears as the only injury to the lower urinary tract. Two patients had both extraperitoneal bladder tears and posterior urethral injuries. One patient had both an extraperitoneal tear at the bladder base and an intraperitoneal rupture at the bladder dome. The seventh patient had an isolated posterior urethral injury. All seven bladder injuries were detected with CT. In these cases, CT findings included (1) free intraperitoneal contrast material (one case), (2) focal contrast extravasation (three cases), and (3) paravesical fluid collections that on delayed CT scans revealed contrast accumulation in the fluid, indicating extravasation (two cases). The seventh bladder injury was suspected on CT and confirmed with retrograde urethrography. Only one of three posterior urethral injuries was detected with CT. Our results suggest that CT is sensitive in the detection of bladder injuries, but not for the diagnosis of urethral injuries.     

Upper abdominal trauma: pitfalls in CT diagnosis

Medical records and computed tomographic (CT) scans of 83 patients with upper abdominal trauma were retrospectively reviewed to determine errors in diagnosis using CT. Patients with possible pancreatic injury, small bowel perforation, or injury to an occult malignancy represented the most difficult diagnostic cases. A false-positive diagnosis of pancreatic injury occurred in seven of 77 patients (9%) and represented the most frequent error in the series. In three patients with subsequently surgically proved small bowel perforation, one duodenal and two proximal jejunal, the injuries were not correctly diagnosed on CT scans. In retrospect, positive CT findings were present in the case of duodenal rupture. Additionally, in two patients, duodenal rupture was suspected based on CT findings of extraluminal gas and fluid near the duodenum, but both cases were proved normal at surgery. The series included three patients with trauma involving unsuspected tumors in the liver, kidney, and stomach.     

Computed tomography in the diagnosis of traumatic rupture of the thoracic aorta

Over a 26-month period, 25 patients admitted to the Trauma Unit at UCSD Medical Center following blunt trauma were investigated for suspected traumatic rupture of the thoracic aorta by computed tomography (CT) of the chest. A retrospective review of these patients was performed. Twenty-one (84%) also had CT of other body areas, most commonly the head or abdomen. Nine of the 25 patients subsequently had aortography; in 15 patients the CT findings were felt at the time to exclude rupture, and one patient was not investigated further because of severe head injuries. In general, if CT failed to show a mediastinal haematoma, aortography was not performed. However, five patients with CT evidence of a haematoma, including two with vertebral fractures, were not investigated by aortography. Two of the 25 patients (8%) had angiographically proven aortic ruptures; in both CT had shown not only a haematoma but also an abnormal outline of the aorta on contrast-enhanced scans. The haematoma was large in one patient and small in the other. Although 10 of the 25 patients had unenhanced scans, no case of aortic rupture is known to have been missed. During the same study period, 47 patients were investigated for suspected aortic rupture solely by aortography. Four patients (8% of this group) had aortic rupture, and two had subclavian or innominate artery ruptures. Only a minority (approximately one-quarter) also had CT of the head or abdomen. The role of CT in the diagnosis of traumatic rupture of the aorta is critically assessed in the light of our experience and a review of the literature.     

Intra-articular knee injuries in patients with knee extensor mechanism ruptures

The knee extensor mechanism is composed of the quadriceps tendon, patella and patellar tendon. Rupture of either the quadriceps tendon or patella tendon is a rare but significant injury. The purpose of our study is to determine if there are any associated injuries with these ruptures necessitating the need for further evaluation such as MRI or arthroscopy. We retrospectively reviewed all patients with ruptures of the knee extensor mechanism who required operative repair at our institution over the last 10 years. We reviewed the chart for any documented associated injury. The type and incidence of associated injuries were recorded. We further divided these patients into two groups: low energy indirect mechanism or high-energy direct impact mechanism. Sixty-four patients met our requirements for inclusion in this study. Thirty-three patients with patellar tendon ruptures and thirty-one patients with quadriceps tendon ruptures were included. Ten out of 33 (30%) patients with a patellar tendon rupture had an associated injury. Four out of 25 (16%) patients with patellar tendon ruptures in the low energy mechanism category had an associated injury. Six out of 8 (75%) patients with a high-energy direct impact patellar tendon rupture had an associated injury. Three out of 31 (10%) patients with quadriceps tendon rupture had an associated injury. The most common associated injuries in the patellar tendon rupture patients were anterior cruciate ligament tears (18%) and medial meniscus tears (18%). We found almost one-third of all patients with a patellar tendon rupture had an associated intra-articular knee injury. We found 10% of patients with quadriceps tendon rupture had an associated intra-articular knee injury. We also found an even higher incidence of associated injuries in patients with high-energy direct impact mechanism patellar tendon ruptures (75%). The most common associated injuries in patients with patellar tendon ruptures were tears of the anterior cruciate ligament (18%) and medial meniscus (18%). We recommend that consideration be given in obtaining a MRI or diagnostic arthroscopy in patients with patellar tendon ruptures especially those with high-energy direct impact mechanism. To our knowledge this has not previously been documented in the literature.     

MR versus MR arthrography in detection of supraspinatus tendon tears in patients without previous shoulder surgery

Purpose

We report the prevalence of supraspinatus tendon tears seen on MR arthrography that are not seen on conventional MR exam in the same patient population.

Materials and methods

A total of 150 consecutive conventional shoulder MR and MR arthrography exams performed on the same patients who went on to arthroscopy were reviewed retrospectively by consensus reading of two musculoskeletal radiologists. Full-thickness supraspinatus tendon tears were assessed. None of the patients had previous shoulder surgery.

Results

There were 113 full-thickness supraspinatus tendon tears seen on conventional MR exam while there were 119 full-thickness supraspinatus tendon tears seen on MR arthrography. The six additional full-thickness supraspinatus tendon tears seen on MR arthrography but not seen on conventional MR exam were confirmed at arthroscopy.

Conclusions

Some full-thickness supraspinatus tendon tears are not seen on conventional MR exam but are seen on MR arthrography. This is most likely due to fibrosis at the supraspinatus tendon tear site simulating an intact tendon on conventional MR.     

Recognition of lumbar disk herniation with NMR

Fifteen nuclear magnetic resonance (NMR) studies of 14 patients with herniated lumbar intervertebral disks were performed on the UCSF NMR imager. Computed tomographic (CT) scans done on a GE CT/T 8800 or comparable scanner were available at the time of NMR scan interpretation. Of the 16 posterior disk ruptures seen at CT, 12 were recognized on NMR. Diminished nucleus pulposus signal intensity was present in all ruptured disks. In one patient, NMR scans before and after chymopapain injection showed retraction of the protruding part of the disk and loss of signal intensity after chemonucleolysis. Postoperative fibrosis demonstrated by CT in one patient and at surgery in another showed intermediate to high signal intensity on NMR, easily distinguishing it from nearby thecal sac and disk. While CT remains the method of choice for evaluation of the patient with suspected lumbar disk rupture, the results of this study suggest that NMR may play a role in evaluating this common clinical problem.     

Right lower quadrant pain and suspected appendicitis: nonfocused appendiceal CT--review of 100 cases

PURPOSE: To determine the value of standard, nonfocused computed tomography (CT) in examining patients with right lower quadrant (RLQ) pain and suspected appendicitis. MATERIALS AND METHODS: The CT scans and medical records of 100 consecutive patients who presented to the emergency department with RLQ pain and were clinically suspected of having appendicitis were retrospectively reviewed. Helical CT of both the abdomen and pelvis was performed at 7-mm increments after oral and intravenous contrast material administration. CT scans were evaluated for the presence of appendiceal or other disease. Results were correlated with surgical and pathologic findings in 34 patients or with 3-month clinical follow-up in 66 patients. RESULTS: CT depicted abnormalities in 66 patients (66%). In 59 (59%) patients, the abnormality was located in the pelvis; 23 (39%) of these patients had appendicitis. Seven (7%) patients had abnormalities outside of the pelvis, a region not typically scanned during focused appendiceal imaging. Four of these seven patients required surgery. Thus, if only pelvic focused RLQ CT had been performed, overall sensitivity would have decreased from 99% to 88% (P <.05) and sensitivity for cases necessitating surgery would have decreased from 96% to 82% (P <.05). CONCLUSION: Both abdominal and pelvic CT examinations are necessary to increase sensitivity and identify the many possible causes of RLQ pain in patients with clinically suspected appendicitis.     

Clinical impact of MR arthrography of the shoulder.

PURPOSE: To evaluate the effect of MR arthrography of the shoulder on diagnostic thinking and therapeutic decisions by orthopedic shoulder surgeons. MATERIAL AND METHODS: Orthopedic surgeons completed a questionnaire before and after MR arthrography for 73 consecutive patients. The main indications were suspected rotator cuff abnormalities. The clinical diagnosis, the degree of confidence in this diagnosis, and the therapeutic decision were noted before and after MR imaging. Surgical reports were available for 34 patients. RESULTS: Thirty-four percent of the pre-MR imaging diagnoses were withdrawn after MR imaging, and new diagnoses were made after MR imaging in 13% of the cases. Confidence in the diagnosis increased significantly after MR imaging for supraspinatus and infraspinatus lesions (p<0.05). Changes of therapeutic decision after MR imaging were noted in 36 of the 73 patients (49%). In 23 patients, more invasive therapeutic procedures were initiated after MR imaging, and a more conservative treatment was implemented for 13 patients. Agreement of MR diagnoses with surgery was 94% for supraspinatus tears, 87% for infraspinatus tears, 77% for subscapularis tears, and 81% for biceps tendon lesions. Agreement of clinical diagnoses with surgery was 56%, 83%, 50%, and 64%, respectively. CONCLUSION: MR arthrography of the shoulder has a major effect on diagnostic thinking and therapeutic decisions by orthopedic shoulder surgeons.     

Noncontrast magnetic resonance imaging of superior labral lesions. 102 cases confirmed at arthroscopic surgery

Previous studies report that noncontrast magnetic resonance imaging is limited in the evaluation of the superior glenoid labrum. From our magnetic resonance imaging database of 2552 patients, we prospectively identified 104 patients with superior labral lesions who subsequently went on to arthroscopic surgery. Magnetic resonance images were assessed to identify fraying, flap tears, bucket-handle tears, or displaced flap of fibrocartilage. The biceps tendon was also evaluated. Patients were categorized according to Snyder's classification, and the findings on the magnetic resonance images were correlated with surgical findings. One hundred of the 104 tears suspected on the images were confirmed at surgery. There were four false-positives and two false-negatives, the former reflecting one normal labrum, two meniscoid-type labra, and one sublabral foramen. With arthroscopic surgery as the standard, magnetic resonance imaging had a sensitivity of 98.0% (100 of 102), a specificity of 89.5% (34 of 38), and an accuracy of 95.7% (134 of 140) for detection of superior labral lesions. We concluded that high-resolution noncontrast magnetic resonance imaging can accurately diagnose superior labral lesions and aid in surgical management.     

Utility of routine trauma CT in the detection of bladder rupture

RATIONALE AND OBJECTIVES: The purpose of this study was to determine the frequency with which routine computed tomography (CT) fails to depict bladder rupture, the potential utility of delayed CT scans, and whether these findings might be useful in determining which patients may require subsequent cystography. MATERIALS AND METHODS: Cystograms and abdominal and pelvic CT scans of 54 patients with blunt trauma and in whom bladder rupture was clinically suspected were retrospectively reviewed. Blind readings of CT scans were performed by two genitourinary radiologists. Cystograms were used as the standard. RESULTS: Cystograms depicted bladder rupture in 10 patients. On CT scans, extravesical fluid was depicted in all three patients with intraperitoneal bladder rupture (although only a small amount of pelvic intraperitoneal fluid was present in two of these patients), in all seven patients with extraperitoneal bladder rupture, and in 32 of the 44 patients without bladder injury. Contrast material had been excreted into the bladder at the time of the initial or delayed CT in eight patients with bladder rupture; however, extravasation was identified in only four of the eight. In two of the four patients without extravasation, the bladder was distended at the time of CT. No bladder injuries were found in the 12 patients in whom pelvic fluid was not identified on CT scans. CONCLUSION: The absence of pelvic fluid on a trauma CT scan indicates that bladder rupture is unlikely. Even when a partially opacified bladder is passively distended, bladder injury may be present despite the absence of contrast material extravasation.     

Dynamic sonographic evaluation of peroneal tendon subluxation

OBJECTIVE: Peroneal tendon subluxation is a major cause of posttraumatic lateral ankle pain. Because peroneal subluxation often occurs only when the foot is dorsiflexed and everted, findings on static imaging studies may appear to be normal. We therefore evaluated the effectiveness of sonography in revealing peroneal tendon subluxation in patients performing stress maneuvers. MATERIALS AND METHODS: From June 2001 to June 2003, 13 consecutive patients (10 females and three males; mean age, 30.4 years; age range, 16-66 years) in whom peroneal tendon subluxation was clinically suspected were scanned with a high-frequency linear array transducer by an experienced sonologist. The ankles in 10 asymptomatic volunteers were also scanned. Sequential axial and longitudinal sonograms of the peroneus longus and peroneus brevis tendons at rest were obtained and evaluated for tendinitis and tendon tears. Real-time axial sonograms were then obtained while the foot was dorsiflexed and everted. Of the 13 patients, 12 had sonographic findings of peroneal tendon subluxation and underwent surgical exploration. The sonographic and surgical reports of these 12 patients were compared. RESULTS: All 12 patients with sonographic findings of peroneal tendon subluxation were subsequently found to have subluxation at surgery. The positive predictive value of dynamic sonography for peroneal tendon subluxation was therefore 100%. Sonography revealed peroneus brevis tendon tears in five patients and a peroneus longus tear in one; all findings were confirmed at surgery, with no false-positive sonograms. Only four of the 20 asymptomatic ankles showed subluxation, and none had any other tendon abnormalities. CONCLUSION: Sonography is an effective technique for diagnosing peroneal tendon subluxation, as well as associated tears of the peroneal tendons.     

Classification of parenchymal injuries of the lung

Pulmonary contusion, implying interstitial and alveolar injury without significant laceration, has been accepted as the primary lung injury in nonpenetrating chest trauma. Computed tomographic (CT) findings were compared with those of chest radiography in 85 consecutive patients with chest trauma in which there was a pulmonary radiodensity consistent with pulmonary contusion or patients with a history of severe chest trauma with normal parenchyma despite rib fractures, hemothorax, pneumothorax, or widened mediastinum. CT was found to be more sensitive than radiography in that 151 abnormalities (excluding rib fractures) were demonstrated on radiographs versus 423 abnormalities on CT scans, and 99 lacerations were seen on CT scans versus five on radiographs. Pulmonary lacerations were classified into four types on the basis of CT findings and mechanism of injury: compression rupture, compression shear, rib penetration, and adhesion tears. In these cases, pulmonary laceration was shown to be an integral component of the mechanism of injury in pulmonary contusion, pulmonary hematoma, pulmonary cyst or pneumatocele, or cavitation in pulmonary contusion.     

The patellar tendon: thickening,internal signal buckling,and other MR variants

We studied the range of appearance of asymptomatic patellar tendons and evaluated the effect of age, weight, joint effusions, and anterior cruciate ligament (ACL) tears on this tendon. One hundred and seventy-three patellar tendons in asymptomatic patients were studied at 1.5 tesla. Sagittal short and long TE images were evaluated in regard to tendon thickness, ratio of thickness of patellar to quadriceps tendons, frequency, location, and severity of intratendon signal, and frequency and severity of tendon buckling. Results were correlated with patient age, sex, weight, the presence of ACL tears, and relative volumes of joint fluid. The mean thickness of the patellar tendon was 0.52 cm. The patellar to quadriceps tendon ratio was 0.72. The patellar tendon frequently (74%) had focal areas of signal apparently within it. This signal was usually subtle, V-shaped (95%), and seen posteriorly in the proximal end of the tendon (82%). Intratendon signal was also seen commonly in the inferior aspect of the tendon (32%). This signal intensity did not increase with greater T2-weighting (99%). Buckling of the patellar tendon was a frequent asymptomatic variant (71%) but was also associated with joint effusions (p<0.01) and ACL tears (p=0.01). Buckling, intratendon signal, and tendon thickness increased with weight and age. Variation of the magnetic resonance appearance of the patellar tendon is frequent. Many of these changes appear to represent subclinical degeneration. Buckling of this tendon also may occur secondary to joint effusions or ACL tears.     

111 In-labeled leukocytes in the detection of prosthetic vascular graft infections

Making a clinical diagnosis of infection in prosthetic vascular grafts is difficult but when undiagnosed, this condition has a high mortality rate. Using Indium-111-labeled white-blood cells, 30 scans were performed in 21 patients suspected of having a prosthetic graft infection. The diagnosis of infected graft was confirmed by surgery in all cases, and lack of infection was established by resolution of symptoms with conservative therapy. Twenty-four hour scans of autologous Indium-111 leukocytes were obtained, and correlative CT studies were done in 11 cases. There were 13 infected grafts at surgery (purulent material present), and scans were positive in all (100% sensitivity); of 17 scans, there were 15 true negatives and two false positives (88% specificity). Using the criteria of gas or fluid around the graft, the sensitivity of CT was only 37% in a small subset of these patients. One-half of the cases in which infection was suspected clinically had no infection and had negative scans. Various types of grafts and graft materials were used, and there was no correlation with presence or absence of infection on the basis of the type of graft. Extragraft infection sites were found in five patients. In conclusion, use of Indium-111 leukocytes has been found to be an accurate and valuable diagnostic method for evaluation of suspected prosthetic vascular graft infection, and to have higher diagnostic accuracy than CT.