Comparative Thrombolytic Properties of Tissue-Type Plasminogen Activator and of a Plasminogen Activator Inhibitor-1 -Resistant Glycosylation Variant, in a Combined Arterial and Venous Thrombosis Model in the Dog

rt-PA-K, a variant of recombinant tissue-type plasminogen activator (rt-PA) with substitution of amino acids 296 to 299 with alanine (KHRR296-299AAAA) has increased fibrin-specificity and reduced sensitivity to plasminogen activator inhibitor-1; rt-PA-T, with threonine 103 replaced by asparagine has an additional glycosylation site and a reduced clearance; and rt-PA-N, with asparagine 117 mutagen-ized to glutamine lacks the high mannose carbohydrate side chain. We have investigated whether combination of these properties in a single molecule might yield an improved thrombolytic agent.

The thrombolytic potency and fibrin-specificity of the combination mutant rt-PA-TNK was compared with that of rt-PA in a combined venous whole blood clot model and platelet-rich arterial eversion graft thrombosis model in dogs given intravenous heparin and aspirin. Infusion of 0.125 to 1.0 mg/kg over 60 min in groups of 4 to 5 dogs produced dose-dependent fibrin-specific venous clot lysis. The thrombolytic potency (percent lysis per mg compound administered per kg body weight) of rt-PA-TNK was significantly higher than that of rt-PA as evidenced by a higher maximal rate of lysis of 480 ± 100% versus 140 ± 40% within the 2 h observation period per mg of compound administered per kg body weight (mean ± SEM, p = 0.004) and a significantly lower dose of 0.08 ± 0.01 versus 0.21 ± 0.04 mg/kg body weight at which the maximal rate of lysis was obtained (p = 0.004). This higher thrombolytic potency was the result of a significantly reduced clearance (240 ± 32 versus 540 ± 49 ml/min, p = 0.002) and a similar specific thrombolytic activity (percent lysis per |ig/ml plasma antigen level). Arterial reflow was obtained with 1 mg/kg rt-PA and with 0.5 mg/kg rt-PA-TNK, but with each agent recanalization was consistently associated with cyclic reocclusion and reflow. The frequency of arterial recanalization was somewhat higher with rt-PA-TNK (10/12) than with rt-PA (4/12) (p = 0.07) but the total patency times during a 2 h observation period were similar.

Limiting Systemic Plasminogenolysis Reduces the Bleeding Potential for Tissue-type Plasminogen Activators but not for Streptokinase

Clinical experience suggests that thrombolytic-induced bleeding is associated with systemic activation of the thrombolytic system. Using fibrin specific variants of tissue-type plasminogen activator (t-PA) and making use of the apparent fibrin specificity of streptokinase (SK) in the rabbit we tested the hypothesis that minimizing systemic plasmin production and fibrinogenolysis will decrease hemorrhages in models of peripheral bleeding and embolic stroke. t-PA consumed 51% of the available fibrinogen; caused cerebral bleeds and increased peripheral bleeding time. Fibrin-specific variants of t-PA depleted less than 20% of the fibrinogen and did not cause peripheral or cerebral bleeding. However, an equipotent dose of SK converted only 12% of the available fibrinogen but increased bleeding time and caused hemorrhagic conversion in 75% of embolic stroke model animals treated. The data suggest that bleeding associated with tissue-type plasminogen activators is linked to systemic plasmin generation and subsequent fibrinogenolysis. This hypothesis does not explain the mechanism(s) of SK-in-duced bleeding.

A Variant of t-PA (T103N, KHRR 296-299 AAAA) that, by Bolus, Has Increased Potency and Decreased Systemic Activation of Plasminogen

In the accompanying paper, we reported that the properties of decreased plasma clearance rate, increased fibrin specificity, and resistance to inactivation by PAI-1 could be effectively combined in the t-PA variant T103N, KHRR 296-299 AAAA. In the current study we evaluated the in vivo efficacy of this variant as well as variants containing the individual mutations T103N and KHRR 296-299 AAAA. Plasma clearance and in vivo lysis of whole blood and platelet-rich clots were determined in a rabbit arterio-venous shunt model. The T103N containing variants were administered as an intravenous (i.v.) bolus. KHRR 296-299 AAAA and t-PA were infused i.v. over 90 min. The clearance rate of the KHRR 296-299 AAAA variant was similar to t-PA. However, the clearance of the T103N and T103N, KHRR 296-299 AAAA variants were 8 and 6-fold reduced, respectively. Potency of the variants relative to t-PA on whole blood clots ranged from 0.9 (T103N, KHRR 296-299 AAAA) to 1.7 (T103N). Relative potency on platelet-rich clots ranged from 2.4 (T103N) to 4.2 (T103N, KHRR 296-299 AAAA). Fibrinogen concentrations in rabbits 120 min after dosing with a 2.5 mg/kg bolus were: 24, 16, 82, and 77% of initial for t-PA; T103N; KHRR 296-299 AAAA; and T103N, KHRR 296-299 AAAA treatment groups, respectively. These results suggest that the T103N, KHRR 296-299 AAAA variant of t-PA, given as a bolus, could result in greater efficacy, particularly on refractory platelet-rich clots, without inducing the severe systemic lytic state produced by a bolus of a less fibrin specific variant.

A Slow Clearing, Fibrin-Specific, PAI-1 Resistant Variant of t-PA (T103N, KHRR 296-299 AAAA)

Site directed mutagenesis was used to construct a t-PA variant that contains an additional glycosylation site in the first kringle domain (T103N) combined with a tetra-alanine substitution in the protease domain (KHRR 296-299 AAAA). This combination variant has a plasma clearance rate that is 4.5-fold slower in rats and 5.4-fold slower in rabbits than t-PA. It is also less than one tenth as active as t-PA towards plasminogen in the presence of fibrinogen, and has approximately twice the normal activity in the presence of fibrin. It shows substantial resistance to the fast acting inhibitor, plasminogen activator inhibitor-1 (PAI-1), requiring a 10-fold greater molar excess of PAI-1 to reduce its activity by 50%, compared to t-PA. This is the result of a reduction of nearly 100-fold in the second order rate constant for PAI-1 inactivation. These results show that it is possible to combine mutations in different domains of t-PA to construct a variant which is simultaneously slower clearing, less reactive towards plasminogen in the absence of a fibrin clot, and resistant to inactivation by PAI-1.

Regenerative treatments to enhance orthopedic surgical outcome

In orthopedic surgery there has been a never-ending quest to improve surgical outcome and the patient's experience. Progression has been marked by the refinement of surgical techniques and instruments and later by enhanced diagnostic imaging capability, specifically magnetic resonance. Over time implant optimization was achieved, along with the development of innovative minimally invasive arthroscopic technical skills to leverage new versions of classic procedures and implants to improve short-term patient morbidity and initial, mid-term, and long-term patient outcomes. The use of regenerative and/or biological adjuncts to aid the healing process has followed in the drive for continual improvement, and major breakthroughs in basic science have significantly unraveled the mechanisms of key healing and regenerative pathways. A wide spectrum of primary and complementary regenerative treatments is becoming increasingly available, including blood-derived preparations, growth factors, bone marrow preparations, and stem cells. This is a new era in the application of biologically active material, and it is transforming clinical practice by providing effective supportive treatments either at the time of the index procedure or during the postoperative period. Regenerative treatments are currently in active use to enhance many areas of orthopedic surgery in an attempt to improve success and outcome. In this review we provide a comprehensive overview of the peer-reviewed evidence-based literature, highlighting the clinical outcomes in humans both with preclinical data and human clinical trials involving regenerative preparations within the areas of rotator cuff, meniscus, ligament, and articular cartilage surgical repair.

The graveyard shift: experience with a night float system

The aim of this study is to describe the effects of a new night float system on the circadian rhythm and clinical judgment of our residents. In addition, the study looks at the residents' opinions of how to optimize the night float system in the future. All 20 of the radiology residents at our institution completed a questionnaire about the night float system after completing their night float coverage. The results of the questionnaire were then compiled and tabulated. It took our residents an average of 2.0 days to become acclimated to the night float and an average of 2.3 days to return to a normal daily routine after completing the night float. No residents perceived impairment in their clinical judgment while on the night float. However, 9 of the 20 residents (45%) stated that their clinical judgment was improved on the night float compared to that of a 24-hour call. Eighteen of 20 residents (90%) preferred the night float system to a 24-hour call system. On average, our residents believe that the optimal number of hours for a night float shift is 10.5 hours and the optimal numbers of days to do the night float consecutively is 6.8 days. In conclusion, a night float system can be a preferable means of evening coverage as it has a minimal effect on the circadian rhythm by allowing residents to become acclimated to working the night shift over the course of several days. The night float system also demonstrates no appreciable adverse effects on clinical judgment and may allow better clinical judgment than a 24-hour call system.

Correlation of the SLAP lesion with lesions of the medial sheath of the biceps tendon and intra-articular subscapularis tendon

BACKGROUND

Superior labral anterior to posterior (SLAP) lesions have been well described in the literature and are thought to be secondary to traction injuries to the biceps anchor and/or falls on the outstretched arm. The pulley has recently been described as a structure that aids in the prevention of biceps instability. The intra-articular subscapularis insertion (IASS) has been noted to contribute to the robust nature of the medial sheath. The purpose of the study was to determine a potential correlation of SLAP lesions and pulley lesions with/without IASS lesions, (hereafter referred to as medial sheath) as forces that can disrupt the biceps anchor and may also disrupt structures of the medial sheath or vice-versa.

MATERIALS AND METHODS

Three hundred and sixteen consecutive shoulder arthroscopies performed by one surgeon were reviewed retrospectively. Operative reports and arthroscopic pictures were carefully reviewed with particular attention paid to the labral and pulley pathology. Selection bias was noted as the author had never operated primarily for a Type 1 SLAP lesion. Following, however, and as such, the exclusion criteria, was a Type 1 SLAP.

RESULTS

There were a total of 30 SLAP lesions and a total of 126 medial sheath lesions. There were 13 patients who had both SLAP and medial sheath lesions. There were 17 patients who had a SLAP lesion without a medial sheath lesion. There were 96 medial sheath lesions without a SLAP. A comparison of rates between patients who had a medial sheath lesion with a SLAP and those who had a medial sheath lesion without a SLAP, for the 316 patients, and when tested with a Fisher exact test revealed that there was no statistical significance, P = 0.673. The prevalence of SLAP lesions in this population of 316 patients was 9.4%, Buford 1%, medial sheath lesions 39%, and SLAP and medial sheath lesions 4%. Interestingly, there were three Buford complexes, all associated with a SLAP and one Buford complex was associated with both a SLAP and a pulley. When looking at the rate for medial sheath lesions when restricted to patients with SLAP lesions, the medial sheath lesion rate was 43.3% (13/30; 95% confidence interval 19.6-66.9%). The medial sheath lesion rate for patients with SLAP lesions differs from a rate of zero and is statistically significant, with a P value <0.05. In other words, when a SLAP lesion is present there is a statistically significant rate of medial sheath lesions, a previously unpublished association.

CONCLUSIONS

With a 43% association of the medial sheath lesion with SLAP lesions, the author postulates that forces that affect the biceps anchor may also damage the pulley system of the bicipital sheath and, as such, this anatomic structure should be evaluated, especially when SLAP lesions are present.

Overwhelming pulmonary infection after a tobogganing accident

A 17-year-old male patient presented to St Joseph's Healthcare (Hamilton, Ontario) with a radiologically opacified left hemithorax. Three days earlier, the patient had injured his left lower chest while tobogganing on his farm. He developed dyspnea and felt unwell, but only sought medical attention from his family doctor a few days after the injury, when fever and pleuritic chest pain ensued. He was treated with a nonsteroidal anti-inflammatory agent, but his chest radiograph revealed an opacified hemithorax, for which he was referred to the hospital. In the emergency department, the patient looked ill and was in distress. His heart rate was 125 beats/min, and he had a blood pressure of 103/61 mmHg, a respiratory rate of 20 breaths/min, a temperature of 38.5°C and an oxygen saturation of 94% on ambient air. Laboratory results showed a white blood cell count of 40×109/L with a left shift. Chest radiography showed a left pleural effusion. A #28 Fr chest tube was inserted into the left hemithorax, and foul-smelling serosanguineous fluid was drained. There was a transient improvement of tachypnea and hypoxemia despite minimal radiographic change. He was admitted and subsequently started on intravenous levofloxacin. Overnight, he deteriorated and required an increase in supplemental oxygen. A computed tomography (CT) scan of his chest revealed multiple loculated fluid collections and bilateral pulmonary parenchymal infiltrates consistent with a pneumonia and empyema.

Arthroscopic bicipital sheath repair: two-year follow-up with pulley lesions

PURPOSE

The purpose of this study was to evaluate arthroscopic repair in patients who had lesions of both the subscapularis insertion/medial head of the coracohumeral ligament and the lateral head of the coracohumeral ligament and supraspinatus tendon (a type 5 biceps subluxation/instability classification), and to determine if primary repair of the torn structures used to reconstruct the bicipital sheath was associated with a high biceps rupture rate. The null hypothesis, that there is no difference between preoperative and postoperative outcomes, was tested.

TYPE OF STUDY

Prospective cohort.

METHODS

Since 1995, the author has had 18 patients who had lesions that affected both the medial and lateral wall of the bicipital sheath. An adjunct was added if tendonitis was present with fraying, and the biceps tendon was debrided if the fraying consisted of 50% or less the width of the tendon. This was chosen arbitrarily. Greater than 50% fraying of the biceps tendon was treated with repair of the supraspinatus and subscapularis. The biceps tendon was treated with tenotomy or tenodesis in these cases and these patients were not included in this study. This article reports on the repair technique and results having a minimum of 2-year follow-up.

RESULTS

There were 12 male patients (age range, 45 to 80 years; average, 62 years) and 6 female patients (age range, 50 to 85 years; average, 66 years). The dominant extremity was involved in 12 of the 16 extremities. Preoperative, ASES Index, Total Constant scores, Subjective Constant scores, Objective Constant scores, visual analog pain scales, and percent function were 31 +/- 19, 53 +/- 13, 12 +/- 8, 41 +/- 8, 7 +/- 3, and 42 +/- 17, respectively. Postoperative scores were 80 +/- 14, 77 +/- 10, 30 +/- 4, 47 +/- 7, 2 +/- 2, and 84 +/- 14, respectively. The null hypothesis was rejected at a level of P = .001, .001, .001, .05, .001, and .001, respectively.

CONCLUSIONS

There was 1 biceps disruption in this cohort following repair, for an incidence rate of 6%. There were 2 patients, active tennis players, who had recurrence of biceps inflammation in the follow-up period with no evidence of biceps subluxation. The arthroscopic technique reported is a primary repair used to reconstruct the normal structures of the groove. This may explain why previous recommendations not to reconstruct the groove because of the high biceps disruption rate have been noted previously. This study did not deepen the groove, tubulize the biceps tendon, or close the rotator interval in nonanatomic fashion. This arthroscopic technique is technically feasible and can alleviate the symptoms of biceps tendon inflammation and/or subluxation in the majority of cases in this cohort.

LEVEL OF EVIDENCE

Level IV, Case Series.

Effect of fibrin glue on air leak and length of hospital stay after pulmonary lobectomy

AIM

Air leaks are a common cause of morbidity and prolonged hospital stay after pulmonary lobectomy. We reviewed our experience with intraoperative fibrin glue to determine if it reduced air leak and improved patient outcomes.

METHODS

Records of patients undergoing pulmonary lobectomy for benign or malignant disease over a 4-year period (1998-2001) were reviewed. Data was collected on age, sex, pulmonary function, pulmonary pathology, use of fibrin glue, duration of chest tube drainage, length of hospital stay, and postoperative complications.

RESULTS

Three hundred and sixty patients underwent lobectomy. Fibrin glue was used intraoperatively to seal air leaks in 102 of the 360 patients (study group: 102;control group: 258). Fibrin glue was used at the discretion of the surgeon, with some surgeons using it routinely. The groups did not differ in age (p=0.29), sex (p=0.42), FEV1 (p=0.57), or pathology (p=0.08). There were no differences in outcomes such as operative mortality (study: 2 of 102, control 6 of 258, p=0.85), empyema (study: 0 of 102, control: 3 of 258, p=0.55), prolonged (>7 days) air leaks (study: 10 of 20; control: 20 of 258, p=0.71), or length of hospital stay (study: 6.3+/-2.5 days, control:7.7+/-7.2 days, p=0.83). The use of fibrin glue was associated with a reduction in the duration of chest tube intubation (study: 4.1+/-3.2 days, control: 5.5+/-3.8 days, p=0.001).

CONCLUSION

Patients treated intraoperatively with fibrin glue had a significantly shorter duration of chest tube intubation after pulmonary lobectomy than those treated conventionally. However, the use of fibrin glue did not significantly influence more clinically relevant outcomes such as length of hospital stay and incidence of prolonged (>7 days) air leaks.

Arthroscopic repair of massive rotator cuff tears: a prospective cohort with 2- to 4-year follow-up

PURPOSE

The goal of this study is to report on the complete arthroscopic repair of massive rotator cuff tears.

TYPE OF STUDY

Prospective cohort study.

METHODS

Between 1997 and 1999, 37 patients underwent complete arthroscopic repair of massive rotator cuff tears. The preoperative and postoperative outcomes of these 37 patients were analyzed using the constant score, American Shoulder and Elbow Society (ASES) index, visual analog pain scale (VAS), a single question of percent function compared with the opposite unaffected extremity, and a single question reflecting satisfaction (Would you undergo the surgery and the postoperative rehabilitation to achieve the result you have today?). The null hypothesis that was tested was that there was no difference between the preoperative and postoperative outcomes. The 37 patients were divided, by cohort design, into 2 groups; massive anterosuperior (AS; subscapularis, supraspinatus, and infraspinatus with or without the teres minor) and massive posterosuperior (PS; supraspinatus and infraspinatus, with or without the teres minor) tears. Additionally, the null hypothesis that there was no difference between outcomes for massive AS and massive PS subgroups was tested.

RESULTS

There was no statistically significant difference between either subset of massive rotator cuff tears with respect to preoperative and postoperative outcomes. The null hypothesis was supported for between groups. All but 2 patients said that they would undergo surgery again to achieve the postoperative state.

CONCLUSIONS

The arthroscopic repair of massive rotator cuff tears is effective for decreasing pain and improving the functional status of the shoulder for most patients. Complete coverage was achieved in 78% of the patients at the time of surgery. A subset of patients who did not have complete coverage or coverage at a second setting showed similar outcomes as those with full coverage. The patient satisfaction rate was 95%.

Arthroscopic repair of full-thickness supraspinatus tears (small-to-medium): A prospective study with 2- to 4-year follow-up

PURPOSE

The objective of this study is to report on the complete arthroscopic repair of full-thickness tears of the supraspinatus.

TYPE OF STUDY

Prospective cohort study.

METHODS

Between 1995 and 1999, 139 full arthroscopic rotator cuff repairs were performed; 37 were repairs of full-thickness supraspinatus tears. Between 1997 and 1999, there were 24 patients who had a complete arthroscopic repair of supraspinatus tears. The preoperative and postoperative status of these patients was analyzed using the Constant score, American Shoulder and Elbow Society Index (ASES Index), a Visual Analog Pain Scale (VAS), a single question of percent function compared with the opposite unaffected extremity, and a single question reflecting satisfaction, "Would you undergo the surgery and the postoperative rehabilitation to achieve the result you have today?" There were 37 patients who had preoperative to postoperative VAS, percent function, postoperative acromiohumeral interval, and clinical rerupture incidences evaluated. The null hypothesis was tested and there was no difference between the preoperative to postoperative outcomes. Two groups were evaluated, those who had concomitant decompression and those who did not.

RESULTS

The null hypothesis was not supported. The 4 scoring systems used for evaluation showed statistically significant improvement from preoperative to postoperative. There were no differences in outcome based upon sex or age as a variable. All patients would have surgery again to achieve their postoperative state.

CONCLUSIONS

The arthroscopic repair of supraspinatus tears is effective for improving the functional status of the shoulder.

Arthroscopic repair of isolated subscapularis tears: A prospective cohort with 2- to 4-year follow-up

PURPOSE

The goal of this study was to evaluate the outcomes of the arthroscopic repair of isolated subscapularis tears. Additionally, this study explores details of the clinical diagnosis, magnetic resonance arthrography findings, and surgical repair techniques.

TYPE OF STUDY

A prospective cohort.

METHODS

The preoperative and postoperative status of patients with isolated subscapularis tears were analyzed using the Constant Score, American Shoulder and Elbow Society Index (ASES Index), a visual analog pain scale (VAS), a single question of percent function compared with the opposite unaffected extremity, and a single question reflecting satisfaction: "Would you undergo the surgery and the postoperative rehabilitation to achieve the result you have today."

RESULTS

There was a statistically significant difference for all outcome measures from preoperative to postoperative follow-up at 2 to 4 years, except for the objective Constant Score. There were no differences based on gender. Preoperative magnetic resonance arthrography aids in the confirmation of the subscapularis tear.

CONCLUSIONS

The arthroscopic repair of the isolated subscapularis tear provides for reliable expectations of improvement in function, particularly the use of the arm behind the back, decreases in pain, decreases in biceps subluxation or instability, and the return of active normal internal rotation. Subjectively, magnetic resonance arthrography is better than magnetic resonance imaging for visualizing the subscapularis tear.

Arthroscopic repair of anterosuperior (supraspinatus/subscapularis) rotator cuff tears: a prospective cohort with 2- to 4-year follow-up. Classification of biceps subluxation/instability

PURPOSE

The purpose of this study was to evaluate the outcome of patients who underwent arthroscopic repair of anterosuperior rotator cuff tears. The null hypothesis, that there was no difference between preoperative scores and postoperative scores, was tested statistically.

TYPE OF STUDY

A cohort study.

METHODS

The preoperative and postoperative status of patients with anterosuperior rotator cuff tears was analyzed using the Constant score, American Shoulder and Elbow Society Index (ASES Index), a visual analog pain scale (VAS), a single question of percent function compared with the opposite unaffected extremity, and a single question reflecting satisfaction, "would you undergo the surgery and the postoperative rehabilitation to achieve the result you have today." There were also 2 groups compared: 1 that had a "tac" used for repair of the subscapularis tendon, and the other that used a "tie" technique for subscapularis repair. All supraspinatus tendon tears were complete and were repaired using a soft-tissue fixation device.

RESULTS

There was a statistically significant difference for all outcome measures except for the objective Constant score of the tie group, P =.58. Follow-up was 2 to 4 years. There were no differences based on sex or type of fixation device used for repair of the subscapularis tendon. There were no reruptures, clinically.

CONCLUSIONS

The arthroscopic repair of anterosuperior rotator cuff tears provides reliable expectation for improvement in function, decreases in pain, decreases in clinical findings of biceps subluxation and inflammation, improvement in shoulder scores, and the improvement of clinical findings of subscapularis insufficiency.

PACS monitors: an evolution of radiologist's viewing techniques

When initially evaluating picture archiving communication systems (PACS) many radiologists try to duplicate the film environment and believe that multiple monitors are required to maintain the productivity of the radiologist. The authors were under the same impression initially but found that they underwent a paradigm shift over a period of time. This report documents the evolution that the radiologists underwent. The author's department consists of 28 diagnostic radiologists and 21 residents who actively read cases on a PACS. The department has been filmless for 6 months, although they have been reading soft copy films for 2 years. All modalities except mammography are included. The authors conducted interviews with both attending radiologists and residents to evaluate the change in methodology from the preconceptions to initial use to current use. The number and kind of monitors preferred for plain films, ultrasound scan, computed tomography (CT), and magnetic resonance imaging (MRI) were recorded. Additionally, viewing methods of different modalities were discussed. The authors found that there was a decrease in the number of monitors from preconceptions to actual use. Furthermore, to a lesser degree, there is a reduction of monitors used initially to that which is currently being used. The style of viewing cross-sectional images has changed. There has been a decrease in the number of images displayed on each monitor. The use of the roller ball on the mouse has affected this viewing style. Changing from a film-based reading environment to PACS environment not only brings about change in the overall technology in image delivery but also in the viewing techniques by radiologists. At our institution we have evolved from initially expecting to use 4 monitors all the time to actually preferring 2 monitors and occasionally 1 monitor to view images. Presentation software and viewing aids such as the roller ball on a mouse for viewing CTs in stack mode are key contributions to this paradigm shift. The decrease in monitors makes PACS more affordable and will allow further penetration of filmless radiology. The authors have found that after using PACS, radiologists prefer using 2 monitors. The style of reading films has changed with experience. Hospitals that plan to purchase PACS should consider this and ensure that the vendor has presentation software that optimizes the 2 monitor system.

Delivering images to the operating room: a web-based solution

As radiology departments become filmless, they are discovering that some areas are particularly difficult to deliver images. Many departments have found that the operating room is one such area. There are space constraints and difficulty in manipulating the images by a sterile surgeon. This report describes one method to overcome this obstacle. The author's institution has been using picture archiving and communication system (PACS) for approximately 3 years, and it has been a filmless department for 1 year. The PACS transfers images to a webserver for distribution throughout the hospital. It is accessed by Internet Explorer without any additional software. The authors recently started a pilot program in which they installed dual panel flat screen monitors in 6 operating rooms. The computers are connected to the hospital backbone by ethernet. Graphic cards installed in the computers allow the use of dual monitors. Because the surgeons were experienced in viewing cases on the enterprise web system, they had little difficulty in adapting to the operating room (OR) system. Initial reception of the system is positive. The use of the web system was found to be superior by the surgeons because of the flexibility and manipulation of the images compared with film. Images can be magnified to facilitate viewing from across the room. The ultimate goal of electronic radiology is to replace hardcopy film in all aspects. One area that PACS has difficulty in accomplishing this goal is in the operating room. Most institutions have continued to print film for the OR. The authors have initiated a project that may allow web viewing in the OR. Because of limited space in the OR, an additional computer was undesirable. The CPU tower, keyboard, and mouse were mounted on a frame on the wall. The images were displayed on 2 flat screen monitors, which simulated the viewboxes traditionally used by the surgeons. Interviews with the surgeons have found both positive and negative aspects of the system. Overall impression is good, but the timeliness of the intraoperative films needs to be improved. The author's pilot project of installing a web-based display system in the operating room still is being evaluated. Their initial results have been positive, and if there are no major problems that arise the project will be expanded. These results show that it is possible to provide image delivery to the OR over the intranet that is acceptable to the surgeons.

MR cholangiopancreatography in patients with primary sclerosing cholangitis: interobserver variability and comparison with endoscopic retrograde cholangiopancreatography

OBJECTIVE

The purpose of our study was to determine the degree of interobserver variability and correlation between MR cholangiopancreatography and endoscopic retrograde cholangiopancreatography (ERCP) for the presence of bile duct strictures in patients with primary sclerosing cholangitis.

MATERIALS AND METHODS

For this retrospective study involving 26 patients with primary sclerosing cholangitis, 31 MR cholangiopancreatograms were compared with 30 endoscopic retrograde cholangiopancreatograms. The MR cholangiopancreatograms were independently interpreted by two abdominal radiologists in a blinded, randomized manner for overall image quality, extent of ductal visualization, and the presence and location of bile duct strictures. Unweighted multirater kappa coefficient values were estimated for each comparison.

RESULTS

Visualization of more than 50% of the expected ductal length was possible in the extrahepatic, central intrahepatic, and peripheral intrahepatic bile ducts in 99%, 88%, and 69% of the MR cholangiopancreatograms and 100%, 86%, and 52% of the endoscopic retrograde cholangiopancreatograms, respectively. Strictures were detected in the extrahepatic, central, and peripheral ducts in 53%, 68%, and 87% of the MR cholangiopancreatograms and 73%, 67%, and 63% of the endoscopic retrograde cholangiopancreatograms, respectively. The interobserver agreement for stricture detection was 61% for MR cholangiopancreatography and 76% for ERCP. MR cholangiopancreatographic findings were consistent with ERCP findings for the presence of strictures in 69% of the cases.

CONCLUSION

In patients with primary sclerosing cholangitis, MR cholangiopancreatography better shows the bile ducts and can depict more strictures, especially of the peripheral intrahepatic ducts, than ERCP. MR cholangiopancreatography can be used to noninvasively diagnose and follow up patients with primary sclerosing cholangitis.

Using contrast-enhanced MR cholangiography with IV mangafodipir trisodium (Teslascan) to evaluate bile duct leaks after cholecystectomy: a prospective study of 11 patients

OBJECTIVE

The purpose of our study was to determine whether contrast-enhanced MR cholangiography using IV mangafodipir trisodium can accurately detect the presence and location of bile duct leaks in patients who have undergone cholecystectomy.

SUBJECTS AND METHODS

Our study group included 11 patients with suspected bile duct leaks after cholecystectomy. Axial single-shot fast spin-echo and gradient-echo images were acquired in all patients before and 1-2 hr after IV administration of mangafodipir trisodium. The contrast-enhanced MR cholangiograms were evaluated for image quality, degree of ductal or small bowel opacification, and the presence and location of bile duct leaks, strictures, and stones. MR cholangiograms were correlated with conventional contrast-enhanced cholangiograms obtained in all patients, including endoscopic retrograde cholangiography (n = 10) and percutaneous transhepatic cholangiography (n = 1).

RESULTS

Excretion of mangafodipir trisodium was noted in the intrahepatic and extrahepatic bile ducts in all patients from 1 to 2 hr after IV administration. Bile ducts and fluid collections that contained excreted mangafodipir trisodium showed increased signal intensity on gradient-echo sequences and decreased signal intensity on single-shot fast spin-echo sequences. Conventional contrast-enhanced cholangiography showed the presence of bile duct leaks in six patients and the absence of bile duct leaks in five patients, with false-negative findings in one patient and false-positive findings in one patient for bile duct leak (sensitivity, 86%; specificity, 83%).

CONCLUSION

Contrast-enhanced MR cholangiography with IV mangafodipir trisodium can successfully detect the presence and location of bile duct leaks in patients suspected of having such leaks after undergoing cholecystectomy. More research is necessary before acceptance of this examination as routine in the workup of these patients.

Handsewn or stapled esophagogastric anastomoses after esophagectomy for cancer: meta-analysis of randomized controlled trials

Gastric transposition with esophagogastric anastomosis is a common method of reconstruction after esophagectomy for cancer. The anastomosis can be fashioned using a handsewn or stapled technique. The choice of anastomotic technique is often debated but there is little evidence to support the use of one method over the other. We performed a meta-analysis of randomized controlled trials (RCTs) to determine the effect of esophagogastric anastomotic method (handsewn or circular stapled) on patient outcomes. Medline and manual searches were done (completed independently and in duplicate) to identify all published RCTs that addressed the issue of handsewn or stapled esophagogastric anastomosis after esophagectomy for cancer. The selection process was inclusive; no trials were excluded. Trial validity assessment was done and a trial quality score was assigned. Major outcomes for quantitative data synthesis included operative mortality, anastomotic leaks, anastomotic strictures, cardiac morbidity, and pulmonary morbidity. A random-effects model was used and relative risk was the principal measure of effect. Systematic qualitative review was used for other outcomes such as duration of operation and time to complete the anastomosis. Data on cancer survival were not available in the RCTs. Five RCTs were selected with quality scores ranging from 2 to 3 (5-point Jadad scale). Selection and validity agreement was strong. Relative risk (95% confidence interval, CI; P-value), expressed as handsewn vs. stapled (treatment vs. control), was 0.45 (0.20, 1.00; P=0.05) for operative mortality, 0.79 (0.44, 1.42; P=0.43) for anastomotic leaks, 0.60 (0.27, 1.33; P=0.21) for anastomotic strictures, 0.99 (0.55, 1.77; P=0.97) for cardiac morbidity, and 0.93 (0.63, 1.37; P=0.72) for pulmonary morbidity. Data synthesized from existing RCTs show that handsewn and circular stapled esophagogastric anastomotic techniques give similar results for anastomotic outcomes, such as leaks and strictures. The stapled anastomotic method appears to increase operative mortality (P=0.05). Although it is difficult to explain this finding, it should not be dismissed. Several hypotheses are discussed.

Ureterolithiasis: classical and atypical findings on unenhanced helical computed tomography

Evaluation of patients with acute flank pain using helical computed tomography (CT) is a well-accepted, rapid, and safe procedure in the emergency setting. Various primary and secondary signs are described in the literature for evaluation of these patients. Our purpose is to demonstrate both the classical findings associated with ureteral calculi on unenhanced helical CT and atypical findings and potential pitfalls. We also provide readers with a systematic approach to interpreting unenhanced helical CT scans performed for acute flank pain.

Survival after conservative (palliative) management of pleural malignant mesothelioma

BACKGROUND AND OBJECTIVES

Malignant mesothelioma is a lethal disease. Aggressive multimodality treatment protocols are reportedly associated with improved survival, but the apparent survival benefits may simply reflect patient selection and the variable natural history of this malignancy. Before embarking on our own protocol of experimental treatment for mesothelioma, we sought to identify important prognostic factors and document the survival of patients treated conservatively (with palliative intent only) in our region.

METHODS

We performed a retrospective review of all patients with a diagnosis of malignant mesothelioma seen at our center between 1987 and 1999. Since curative intent treatment had not been given, we assumed that measured survival would largely reflect the natural history of the malignancy.

RESULTS

There were 101 patients (80 males and 21 females). Mean age was 65 +/- 9.2 years. Symptoms of disease were present for a median time of 5 months before the diagnosis was established. The most common presenting symptoms were dyspnea (46 patients), chest pain (30 patients), and weight loss (22 patients). Sixty-eight patients (68%) had a history of asbestos exposure. Mesothelioma subtypes included epithelial (43 patients), sarcomatous (26 patients), mixed (19 patients), desmoplastic (4 patients), and unspecified (9 patients). All 101 patients were treated with palliative intent. Talc pleurodesis was performed in 70 patients. At the time of analysis, 90 patients had died and 11 remained alive. Median survival was 213 (95% CI 137-289) days. Survival for the three major histological subtypes was significantly different (log rank, P = 0.0016). Histological subtype (epithelial favorable) was the only significant independent prognostic factor (Cox proportional hazard regression, P = 0.0009).

CONCLUSIONS

Patients with epithelial mesothelioma survive longer than those with other histological subtypes. Conservatively managed patients with pleural malignant mesothelioma have a median survival of approximately 7 months. These data from conservatively treated patients can serve as baseline information for future studies of experimental treatments.

Cirrhosis: spectrum of findings on unenhanced and dynamic gadolinium-enhanced MR imaging

The appearance of the cirrhotic liver on computed tomography can be difficult to evaluate and can frustrate the radiologist distinguishing benign from malignant lesions. Hepatic edema, fibrosis, atrophy, and vascular abnormalities are common in the cirrhotic liver and produce derangements in morphology, attenuation, and perfusion, limiting the accurate characterization of hepatic masses. With the development of fast magnetic resonance (MR) sequences and dynamic postgadolinium-enhanced imaging, most hepatic lesions with uncertain etiology on computed tomography can be accurately characterized on MR imaging. We describe MR imaging techniques useful for imaging cirrhosis and its complications. We also illustrate the spectrum of findings in the cirrhotic liver on dynamic gadolinium-enhanced MR imaging, including reticular and confluent fibrosis, fatty infiltration, hemochromatosis, regenerating nodules, dysplastic nodules, hepatocellular carcinoma, and sequela of portal hypertension.

A meta-analysis of randomized controlled trials of route of reconstruction after esophagectomy for cancer

BACKGROUND

A gastric conduit is usually used to reconstruct the foregut after esophagectomy for cancer. It can be transposed through a posterior or anterior mediastinal route. The choice of route is often debated but there is little evidence to support the use of one route over the other. We performed a meta-analysis of randomized controlled trials (RCTs) to determine the effect of route of reconstruction on patient outcomes.

METHODS

Medline and manual searches were done (completed independently and in duplicate) to identify all published RCTs that addressed the issue of route of gastric conduit reconstruction after esophagectomy for cancer. The selection process was inclusive; no trials were excluded. Trial validity assessment was done and a trial quality score was assigned. Major outcomes for quantitative data synthesis included operative mortality, anastomotic leaks, cardiac morbidity, and pulmonary morbidity. A random-effects model was used and relative risk was the principal measure of effect. Systematic qualitative review was used for other outcomes such as duration of ventilation, length of hospital stay, operative blood loss, duration of surgery, anastomotic strictures, dysphagia, gastric emptying, and quality of life. Data on cancer survival were not available in the RCTs.

RESULTS

Six RCTs were selected with quality scores ranging from 1 to 4 (5-point Jadad scale). Selection and validity agreement was strong. Relative risk (95% confidence interval; P value), expressed as posterior versus anterior mediastinal route (treatment versus control), was 0.56 (0.17, 1.82; P = 0.34) for mortality, 1.01 (0.35, 2.94; P = 0.98) for leaks, 0.43 (0.17, 1.12; P = 0.08) for cardiac complications, and 0.67 (0.34, 1.33; P = 0.26) for pulmonary complications. Systematic qualitative review did not suggest any difference in other perioperative outcomes or conduit function for the two routes of reconstruction.

CONCLUSIONS

Data synthesized from existing RCTs show that posterior and anterior mediastinal routes of reconstruction are associated with similar outcomes after esophagectomy for cancer. However, a difference in outcomes for the two reconstructive routes remains possible. Further trials with larger numbers of patients are needed.

Canine abdominal MRI at 8 Tesla: initial experience with conventional gradient-recalled echo and rapid acquisition with relaxation enhancement (RARE) techniques

PURPOSE

In this manuscript, we present our initial experience with MRI of the abdomen at 8 T of canine subjects both alive and dead. Our hypothesis is that abdominal imaging at 8 T should be possible and should demonstrate unique information. To our knowledge, this is the first description of imaging characteristics of the abdomen at such field strengths using a human MR scanner.

METHOD

An 8 T, 80 cm magnet housed in our department since 1998 was used for our study. GRE and rapid acquisition by relaxation enhancement (RARE) pulse sequences were selected to give reasonable slice profiles with relatively low power. Three dogs were imaged alive and after being killed.

RESULTS

Our initial results show excellent signal-to-noise ratio and good RF penetration. Structures in the center of the abdomen were well visualized. Homogeneous signal was noted throughout each image without dielectric resonance artifact. Magnetic susceptibility artifacts were most severe on the GRE sequences. On the GRE sequences, the images appeared relatively T2 weighted. Signal voids were seen due to gas in the lung and bowel and susceptibility artifact at subcutaneous fat-muscle boundaries. The liver and spleen showed similar signal intensity, hypointense to subcutaneous muscle at low TE values. There was little internal anatomy of the liver or spleen visible except for the vessels. The kidney, in contrast, demonstrated very good internal structure with visualization of the cortex and medulla. Linear signal voids were depicted in the expected location of normal renal vascular anatomy on the GRE sequences. On the RARE sequences, the images also appeared T2 weighted. Magnetic susceptibility artifacts at subcutaneous fat-muscle boundaries were absent. Signal voids were noted in vessels with blood flow and gas. The liver and spleen were of similar signal intensity and slightly hypointense to muscle. The kidney and pancreas were of higher signal intensity than liver and subcutaneous muscle. The gallbladder wall demonstrated a striated pattern of two layers, with an inner hypointense and an outer hyperintense layer on the RARE sequence. The gastric wall demonstrated a striated pattern of five layers on the RARE sequence.

CONCLUSION

Images of the dog abdomen with the world's first ultra high field 8 T magnet show robust image quality and excellent spatial resolution. Image contrast is greatest on the RARE sequence, and susceptibility artifact is strongest on the GRE sequence.

Self-inflicted pneumothoraces

Self-inflicted pneumothoraces are rare manifestations of psychiatric illness. Two patients with self-inflicted pneumothoraces are reported, and the typical clinical features of factitious disorders are described. If thoracic surgeons are aware of these conditions, inappropriate surgery- and poor outcomes-can be avoided.

Anastomotic leaks after esophagectomy for esophageal cancer: a comparison of thoracic and cervical anastomoses

BACKGROUND AND OBJECTIVES

Esophagogastric anastomotic leaks remain a significant problem after esophagectomy for esophageal cancer. Many investigators have reported that leaks are more frequent after cervical, as opposed to thoracic, esophagogastric anastomoses. We conducted a retrospective review to assess the effect of anastomotic location (thoracic or cervical) on anastomotic leak incidence and severity.

METHODS

Seventy-four consecutive patients with esophageal cancer underwent esophagectomy and esophagogastric anastomoses at our institution over a four-year period. Their charts were reviewed retrospectively and data was collected on age, gender, histology, stage, resection margin status, adjuvant therapy, cancer survival, anastomotic location, anastomotic leaks, and operative mortality.

RESULTS

Cervical anastomoses were done in 19 patients and thoracic anastomoses were done in the other 55 patients. The two groups were similar with respect to age, gender, histology, stage, adjuvant therapy, and overall survival. Operative mortality for the entire group of 74 patients was 4% (3 patients). Resection margins were positive for residual tumor in 2 of 19 (11%) patients with cervical anastomoses and 9 of 55 (16%) patients with thoracic anastomoses (p=0.42). Leaks complicated 1 of 19 (5%) cervical and 9 of 55 (16%) thoracic esophagogastric anastomoses (p=0.21). Positive resection margins and anastomotic leaks were not significantly related (p=0.54). One of 9 (11%) leaks in the thoracic group proved fatal.

CONCLUSIONS

In our experience cervical esophagogastric anastomoses do not have a higher incidence of leaks than thoracic anastomoses.

Open lung biopsy as an outpatient procedure

BACKGROUND

Lung biopsies are frequently needed to diagnose diffuse interstitial lung diseases. Both limited thoracotomy (open lung biopsy) and thoracoscopy can be used for lung biopsies, but both procedures have traditionally required hospital admission. We report a series of patients that underwent outpatient open lung biopsy to show the safety and effectiveness of this practice.

METHODS

We reviewed records of ambulatory, nonoxygen dependent patients with a clinical diagnosis of diffuse interstitial lung disease that underwent outpatient open lung biopsy between January 1997 and December 1999. All procedures were done by a senior surgeon using single lumen endotracheal anesthesia, a small anterolateral thoracotomy without rib spreading, stapled wedge resection, and no chest tube. Patients were discharged the same day.

RESULTS

Thirty-two patients with a clinical diagnosis of diffuse interstitial lung disease underwent outpatient open lung biopsy. Mean age was 58 years (range, 21 to 74 years). Preoperative forced expiratory volume in 1 second was 74.3%+/-7.0% of predicted. A pathologic diagnosis was established in all patients: usual interstitial pneumonia, 26 patients; sarcoidosis, 2; metastatic carcinoma, 2; desquamative interstitial pneumonia, 1; and mixed dust pneumoconiosis, 1 patient. No patient required a chest tube, overnight observation, or hospital admission. No complications occurred.

CONCLUSIONS

Selected patients with a clinical diagnosis of diffuse interstitial lung disease can safely and effectively undergo diagnostic outpatient open lung biopsy. However, careful patient selection and attention to operative detail are essential.

Antitumor activity of the growth hormone receptor antagonist pegvisomant against human meningiomas in nude mice

OBJECT

The authors have previously demonstrated that modulation of the growth hormone (GH)/insulin-like growth factor-I (IGF-I) axis can significantly affect meningioma growth in vitro. These studies were performed to evaluate the efficacy of GH receptor blockade in vivo.

METHODS

Primary cultures from 15 meningioma tumors obtained in humans were xenografted into athymic mice. Approximately 1.5 million cells from each of the 15 tumors were implanted into the flanks of two female mice, one pair for each tumor. One animal from each of the 15 pairs was then treated with the GH receptor antagonist pegvisomant and the other with vehicle alone for 8 weeks. The tumor volume was measured using digital calipers three times per week. The mean tumor volume at the initiation of injections was 284 +/- 18.8 mm3 in the vehicle group and 291.1 +/- 20 mm3 in the pegvisomant group. After 8 weeks of treatment, the mean volume of tumors in the pegvisomant group was 198.3 +/- 18.9 mm3 compared with 350.1 +/- 23.5 mm3 for the vehicle group (p < 0.001). The serum IGF-I concentration in the vehicle group was 319 +/- 12.9 microg/L compared with 257 +/- 9.7 in the pegvisomant group (p < 0.02). A small but significant decrease was observed in circulating IGF binding protein (IGFBP)-3 levels, whereas slight increases occurred with respect to serum IGFBP-1 and IGFBP-4 levels. In the placebo group the tumor weight was 0.092 +/- 0.01 g compared with 0.057 +/- 0.01 g in the pegvisomant group (p < 0.02). The IGF-I and IGF-II concentrations were measured in the tumors by using a tissue extraction method. These human-specific immunoassays demonstrated that there was no autocrine production of IGF-I in any of the tumors, either in the pegvisomant or vehicle group. The IGF-I levels were highly variable (0-38.2 ng/g tissue) and did not differ significantly between treatment groups.

CONCLUSIONS

In an in vivo tumor model, downregulation of the GH/IGF-I axis significantly reduces meningioma growth and, in some instances, causes tumor regression. Because the concentrations of IGF-II in tumor did not vary with pegvisomant treatment and there was no autocrine IGF-I production by the tumors, the mechanism of the antitumor effect is most likely a decrease of IGF-I in the circulation and/or surrounding host tissues. Because the authors have previously demonstrated that the GH receptor is ubiquitously expressed in meningiomas, direct blockade of the GH receptor on the tumors may also be contributing to inhibitory actions.

Prophylactic intracavitary (pneumonectomy space) antibiotic instillation: a comparative study

BACKGROUND AND OBJECTIVES

Postpneumonectomy empyema is a dreaded complication of pneumonectomy. The effectiveness of prophylactic intracavitary antibiotic instillation is not known. We conducted a retrospective review to assess the effect of pneumonectomy space antibiotic instillation on septic complications (empyema and bronchial fistula) of pneumonectomy.

METHODS

Ninety-three consecutive patients underwent pneumonectomy at our institution over a three-year period. Their charts were reviewed retrospectively and data was collected on age, gender, diagnosis, intravenous antibiotics, intracavitary (pneumonectomy space) antibiotics, empyemas, bronchial fistulas, length of hospital stay, and operative mortality.

RESULTS

All 93 patients received 3 perioperative doses of prophylactic intravenous antibiotics. One group (n=47) of patients also received intraoperative intracavitary instillation of an antibiotic solution (penicillin G: 5 million units, bacitracin: 50,000 units, gentamicin: 60 mg, in 1 litre of saline) while the other group (n=46) did not. Age, gender, diagnosis, and length of stay were not significantly different in the two groups. There were no empyemas or bronchial fistulas in the intracavitary antibiotic group. Postpneumonectomy empyemas occurred in 6 (13%) patients (empyema with bronchial fistula: 5, empyema alone: 1) that had not received intracavitary antibiotics (p=0.012). There were 4 deaths (9%) in each group (p=0.63).

CONCLUSIONS

Prophylactic intraoperative intracavitary antibiotic instillation may reduce the incidence of empyemas after pneumonectomy. However, a randomized trial would be needed to prove the effectiveness of this form of prophylactic antibiotic strategy.

Subscapularis, medial, and lateral head coracohumeral ligament insertion anatomy. Arthroscopic appearance and incidence of "hidden" rotator interval lesions

PURPOSE

The purpose of this study was to document the incidence of lesions of the rotator interval, illustrate the arthroscopic appearance of subtle differences in these lesions, and discuss how various lesions may affect biceps tendon stability in the bicipital groove.

TYPE OF STUDY

A Data Registry has been used in my office since 1995 (Microsoft Office Access). This study reports on the results of a retrospective database "query" of the prospectively entered data from 1995 to 1998. Thus, by default, the format of this study is a consecutive sample. Only patients with a disruption of rotator cuff tendons, labrum and/or gleno-coracohumeral ligaments are included by study design.

METHODS

This study has identified and reports on 46 arthroscopically identified subscapularis tears, 25 "hidden" rotator interval lesions (SGHL/MCHL complex) and 6 SGHL/CHL complex plastic deformation lesions in 165 patients undergoing shoulder arthroscopy for conditions ranging from anterior instability to rotator cuff tears. Arthroscopically identified lesions include partial or complete disruptions of the subscapularis tendon, disruptions of the superior glenohumeral/medial head coracohumeral ligament complex (SGHL/MCHL), disruptions of the lateral head coracohumeral ligament (LCHL), and various combinations of the above.

RESULTS

The incidence rate of subscapularis tendon involvement in 165 arthroscopically treated shoulder patients was 27%. The incidence rate of subscapularis tendon disruptions with rotator cuff pathology was 35%. The incidence rate of SGHL/MCHL lesions (tear or stretch) in 165 arthroscopically treated shoulder patients was 18%. The incidence rate of SGHL/MCHL tears in 165 arthroscopically treated shoulder patients was 15%. Forty-seven percent of all subscapularis tears involved the SGHL/CHL complex. Ten percent of all rotator cuff tears involving the supraspinatus tendon involved the LCHL.

CONCLUSIONS

This study has recorded the incidence of lesions of the subscapularis, SGHL/MCHL complex and/or the LCHL, and combinations thereof in degenerative cuff and instability patients. Primary lesions of the rotator interval can occur and regardless of the associated pathology, and if these lesions are not repaired, biceps tendon subluxation may exist.

Detection of bile duct leaks using MR cholangiography with mangfodipir trisodium (Teslascan)

Mangafodipir trisodium (Teslascan), a hepatobiliary contrast agent, has the potential of providing functional biliary imaging similar to hepatobiliary scintigraphy. To our knowledge. the potential role of this biliary contrast agent in the detection of bile duct leaks has not been reported. In this case report, we report the first case of a bile duct leak diagnosed with enhanced MRI with mangafodipir trisodium in a patient following laparoscopic cholecystectomy. Our case illustrates that functional MR cholangiography images can be successfully acquired by using a post-mangafodipir fat-suppressed GRE technique and that bile duct leaks can be detected.

Duration of knowledge in general thoracic surgery

BACKGROUND

Medical knowledge changes rapidly, so current medical education approaches emphasize the development of life-long learning skills ("teaching the learner to learn") as opposed to the simple acquisition of contemporary medical knowledge. Because there are no data on the rapidity of change of general thoracic surgical knowledge, we do not know whether this trend in medical education is appropriate for thoracic surgical trainees. We undertook a study to assess the duration of knowledge in general thoracic surgery.

METHODS

The first general thoracic surgery article from each issue of The Annals of Thoracic Surgery between 1965 and 1997 was abstracted into a summary statement. A form, made up of 360 summary statements in random order, was assessed by 6 general thoracic surgeons. They assessed statement validity on a 5-point scale (1 = statement false; 5 = statement true). Average statement validity scores for 30 time intervals were calculated. The relationship between time of publication and statement validity was analyzed.

RESULTS

Average validity scores ranged from 2.24 (represents 1965 to 1966) to 4.32 (represents 1969 to 1970). Validity scores increased with time (y = 3.46 + 0.017x, where y is validity score and x is time), and this was significant (r = 0.40; p = 0.027). However, the absolute change in average validity scores over the 33-year study period was only 0.52 or 13.1% of the "modern" era scores.

CONCLUSIONS

The assumption that medical knowledge changes quickly may not be true in general thoracic surgery. Although life-long learning skills are important, general thoracic surgery training programs should continue to emphasize fundamental knowledge in the specialty.

Visualization of the anatomy of the rotator interval and bicipital sheath

A systematic evaluation of the glenohumeral joint should be routinely performed with all shoulder arthroscopy and include all anatomic areas. However, to date, less attention has been given to the insertion of the subscapularis tendon, superior glenohumeral ligament (SGHL), and medial head of the coracohumeral ligament (MCHL). This article outlines arthroscopic techniques that may aid in the evaluation of the anatomy of the rotator interval and bicipital sheath. In this apical region, the CHL contributes fibers to the SGHL (forming the internal reflection of the bicipital groove-SGHL/CHL complex), the subscapularis tendon, and the joint capsule. The CHL is more anterior to the SGHL. There is a distinct anatomic difference between the SGHL/CHL insertion complex and the subscapularis insertion. The normal insertion of the subscapularis tendon is into a small trough on the lesser tuberosity. Together, these structures make up the medial wall of the superior biceps pulley. With the arthroscope advanced to the anterior portion of the joint, the shoulder is elevated from 60 degrees to 90 degrees and a neuroprobe is advanced through the anterior cannula. By internally rotating the arm, the subscapularis tendon insertion and SGHL/CHL complex slacken. A neuroprobe can be placed under the insertion of the subscapularis tendon and SGHL/CHL complex. A 70 degrees arthroscope can aid in visualization with less shoulder elevation. These techniques allow for a thorough visualization of the structures of the rotator interval and medial bicipital sheath.

Efficacy and safety of mangafodipir trisodium (MnDPDP) injection for hepatic MRI in adults: results of the U.S. Multicenter phase III clinical trials. Efficacy of early imaging

The efficacy of contrast-enhanced magnetic resonance imaging (MRI) for detecting and characterizing, or excluding, hepatic masses was assessed in 404 patients, following the intravenous administration of mangafodipir trisodium (MnDPDP) injection, a hepatic MRI contrast agent. An initial contrast-enhanced computed tomography (CT) examination was followed by unenhanced MRI, injection of MnDPDP (5 micromol/kg IV), and enhanced MRI at 15 minutes post injection. Agreement of the radiologic diagnoses with the patients' final diagnoses was higher for enhanced MRI and for the combined unenhanced and enhanced MRI evaluations than for unenhanced MRI alone or enhanced CT using the clinical diagnosis as the gold standard. Mangafodipir-enhanced MRI uniquely provided additional diagnostic information in 48% of the patients, and patient management was consequently altered in 6% of the patients. MnDPDP-enhanced MRI was comparable or superior to unenhanced MRI and enhanced CT for the detection, classification, and diagnosis of focal liver lesions in patients with known or suspected focal liver disease.

Comparison of videothoracoscopy and axillary thoracotomy for the treatment of spontaneous pneumothorax

Surgical treatment of spontaneous pneumothorax can be done through a thoracotomy or a video-thoracoscopic approach. Although the videothoracoscopic technique is currently popular it is not obviously superior to a more traditional axillary thoracotomy approach. We compared our recent experience with both techniques to determine the optimal surgical treatment for spontaneous pneumothoraces. A retrospective review of 79 patients treated surgically (34 thoracotomy and 45 thoracoscopy) for spontaneous pneumothoraces was done. Patients were treated between 1991 and 1997. Patients older than 60 years of age and those with spontaneous pneumothoraces secondary to generalized pulmonary emphysema were excluded. There were no operative deaths. Recurrence rate [thoracotomy, two of 34; thoracoscopy, three of 45 (P < 0.89)], air leak exceeding 7 days [thoracotomy, three of 34; thoracoscopy, three of 45 (P < 0.73)], operating room times [thoracotomy, 54 +/- 26 minutes; thoracoscopy, 53 +/- 16 minutes (P < 0.59)], and postoperative length of stay [thoracotomy, 5.7 +/- 4.3 days; thoracoscopy, 4.7 +/- 4.4 days (P < 0.26)] were not significantly different for the two techniques. We conclude that axillary thoracotomy and videothoracoscopy are equally effective surgical treatments for spontaneous pneumothoraces. A large randomized trial would be needed to determine whether one approach is truly superior to the other.

Comparison of Videothoracoscopy and Axillary Thoracotomy for the Treatment of Spontaneous Pneumothorax

Surgical treatment of spontaneous pneumothorax can be done through a thoracotomy or a videothoracoscopic approach. Although the videothoracoscopic technique is currently popular it is not obviously superior to a more traditional axillary thoracotomy approach. We compared our recent experience with both techniques to determine the optimal surgical treatment for spontaneous pneumothoraces. A retrospective review of 79 patients treated surgically (34 thoracotomy and 45 thoracoscopy) for spontaneous pneumothoraces was done. Patients were treated between 1991 and 1997. Patients older than 60 years of age and those with spontaneous pneumothoraces secondary to generalized pulmonary emphysema were excluded. There were no operative deaths. Recurrence rate [thoracotomy, two of 34; thoracoscopy, three of 45 ( P < 0.89)], air leak exceeding 7 days [thoracotomy, three of 34; thoracoscopy, three of 45 ( P < 0.73)], operating room times [thoracotomy, 54 ± 26 minutes; thoracoscopy, 53 ± 16 minutes ( P < 0.59)], and postoperative length of stay [thoracotomy, 5.7 ± 4.3 days; thoracoscopy, 4.7 ± 4.4 days ( P < 0.26)] were not significantly different for the two techniques. We conclude that axillary thoracotomy and videothoracoscopy are equally effective surgical treatments for spontaneous pneumothoraces. A large randomized trial would be needed to determine whether one approach is truly superior to the other.

Cable modem access to picture archiving and communication system images using a web browser over the Internet

This presentation describes our experiences using a web-based viewing software and a browser to view our picture archiving and communication system (PACS) images at a remote site with cable modem-internet communications. Our testing shows that using a cable modem to access our radiology webserver produces acceptable transmission speeds to remote sites. The average time-to-display (TTD) for 16 computed tomography (CT) images on the web-based intranet system in our hospital was 7 to 8 seconds. Using a cable modem and comparable equipment at a remote site, the average TTD is 16 seconds over the internet. The TTD does not significantly change during various hours of the day. Security for our hospital-based PACS is provided by a firewall. Access through the firewall is accomplished using virtual private network (VPN) software, a secure ID, and encryption. We have found that this is a viable method for after-hours subspecialty radiology consultation.

Primary angiosarcoma of the spleen--CT, MR, and sonographic characteristics: report of two cases

Primary angiosarcoma of the spleen is a rare entity, but it is the most common primary splenic malignancy. These tumors demonstrate an aggressive growth pattern and can be single or multiple. The diagnosis should be suspected in a patient who presents with splenomegaly but without evidence of lymphoma, malaria, leukemia, or portal hypertension. The tumor may also present with acute abdominal symptoms secondary to spontaneous splenic rupture. We describe two cases of primary angiosarcoma of the spleen with computed tomographic, magnetic resonance, and sonographic features.