Sequential imaging of post-operative thrombus using the In-111-labelled platelet-specific monoclonal antibody P256

Eleven patients undergoing total hip replacement were studied by radioimmunoscintigraph for development of postoperative thrombus. Images were obtained using the 111In-labelled Fab' fragment of a monoclonal antibody (P256) directed against human platelets. Six patients showed focal accumulation of radioactivity in the lower limbs. Three of these had contrast venograms that were all positive for thrombus. Two of these six patients showed evidence of pulmonary localization of P256-Fab' and this correlated with positive ventilation/perfusion scintigraphy in one of the patients. Sequential imaging with 111In-P256 Fab' not only established a diagnosis of deep venous thrombus but also provided useful information regarding its natural history.

Diagnosis of deep venous thrombosis by duplex sonography

In a prospective study 90 patients with clinically suggested lower limb deep venous thrombosis (DVT) were examined with duplex ultrasonography (US) prior to venography. No attempts were made to examine the calf veins. Five ultrasound examinations were inconclusive. Thirty-four patients had DVT diagnosed at US with a sensitivity of 97 per cent and a specificity of 96 per cent. Compressibility of the vein as assessed by the real-time image was in the acute phase an easy and fast test for DVT, whereas the Doppler data failed to add to the diagnostic accuracy. Twenty-seven patients with DVT were followed during anticoagulant treatment, but only 16 regained fully compressible veins within the observation period of 3 to 6 months. Duplex sonography was useful in monitoring the changes in vein patency during anticoagulant treatment.

[Loco-regional fibrinolysis with urokinase in the treatment of deep venous thromboses]

The importance of the fibrinolytic treatment in deep venous thrombosis, to avoid the mortal pulmonary embolism, among other complications, is commented on. The results in 32 patients, presenting deep venous thrombosis and treated with loco-regional Urokinase, are presented. Author carries out some commentaries about surgical and medical treatment.

[Tennis leg--a differential diagnosis in deep vein thrombosis]

A case of pulmonary embolism in a healthy young man aged 22 years which was caused by prolonged air travel is reported. The patient developed deep thrombophlebitis in the left lower limb and pulmonary emboli in the left lung.

Monoclonal antibodies and thromboembolism

For many years intensive efforts to reliably image thrombi by radionuclide techniques have been unrewarding. Recently, however, monoclonal antibodies to platelet cell-surface antigens and to fibrin polymer have emerged as potent thrombus imaging agents in experimental animals. In Britain antiplatelet antibody has been successful in clinical trials, as has antifibrin in the United States. It is to be hoped that radiolabeled antibody technology will evolve to the point where it can detect thrombi anywhere, including the lungs and brain. The relative efficacy of radionuclide thrombus detection and Doppler ultrasonography is currently undefined.

Deep vein thrombosis: a perspective on anatomy and venographic analysis

Pulmonary thromboembolism affects 750,000 Americans annually. DVT is the primary origin of PE, which results in approximately 150,000 patient deaths annually. Normal variants affect the incidence of DVT. Patients with duplicated or fenestrated superficial femoral veins and patients with five or more valves are at increased risk for development of DVT. Positive contrast venography performed in the radiology department under fluoroscopic control remains the "gold standard" for the diagnosis of DVT, despite the development of other modalities. Low-osmolar contrast agents, either nonionic or dilute ionic, and postprocedure infusion of 2,500 U of heparin mixed in 150 mL of physiologic saline should be used to reduce the incidence of postphlebography DVT. Positive venographic signs of DVT include filling defect, cutoff, nonvisualization, and collateralization.

Pulmonary angiography in pulmonary embolic disease

Pulmonary thromboembolic disease is a serious and common complication in patients with various medical and surgical diseases. Pulmonary angiography is currently accepted as the "gold standard" for the diagnosis of pulmonary embolism, but its role is still somewhat controversial. This review article attempts to answer some of these controversies by exploring the how, when, what, and where of contemporary pulmonary angiography.

Are routine inferior vena cavograms necessary before Greenfield filter placement?

In August 1983 we began routinely studying the inferior vena cava (IVC) before placement of a Greenfield filter. We have performed 83 caval interruptions since that time, but six patients were excluded from this study because an IVC clip had been placed in three patients during other abdominal surgery, and the medical records of three others could not be retrieved. Of the remaining 77 patients, 65 (84%) had IVC venograms taken before placement of their filter. We personally reviewed 63 of these cavograms but had to accept the radiologist's reports for two studies that could not be retrieved. Ten (15%) cavograms showed abnormalities that significantly affected the placement of the filter. The most frequent abnormality was intracaval clot extending above the L3-4 interspace. Other important abnormalities were severe narrowing of the diaphragmatic IVC (two patients) and a tortuous IVC in a patient with severe scliosis. Seven (11%) additional cavograms showed unilateral iliac thrombus that would have influenced the surgical approach had a femoral approach been required. Formal preoperative cavography expedited filter placement and reduced operating time by obviating the need for intraoperative angiograms. Because 26% of the cavograms showed clinically important information, we recommend that routine IVC angiograms be taken before filter placement.

Tc-99m antifibrin Fab' fragments for imaging venous thrombi: evaluation in a canine model

An antifibrin antibody (T2G1s) Fab' fragment labeled with technetium-99m was tested for its ability to produce images of fresh thrombi in dogs. In gamma camera images, all thrombi were evident by 2-4 hours after injection. Mean thrombus-to-blood and thrombus-to-muscle ratios averaged 4.0 and 69 at four hours after injection and increased to 24 and 270, respectively, by 24 hours after injection. When compared with I-125 fibrinogen injected into the same dogs, Tc-99m-antifibrin Fab' had lower absolute uptake in thrombus but higher thrombus-to-blood ratios due to a faster rate of disappearance from the blood. The primary route of excretion was through the kidneys. Tc-99m-antifibrin Fab' was highly stable in vivo, with an average of 82% of the circulating radioactivity able to bind to fibrin at 4 hours after injection. When compared with an In-111-labeled Fab fragment of antifibrin antibody 59D8, thrombus-to-blood and thrombus-to-muscle ratios were slightly higher for the Tc-99m-labeled antibody, and the blood disappearance rate was slightly faster. The absolute uptake in thrombus, however, was not significantly different, and the thrombus was visualized at about the same time after injection. These studies suggest that Tc-99m T2G1s Fab' is a potential agent for detecting thrombi in a clinical setting.

Pulmonary nuclear medicine evaluation of thromboembolic disease

PE is a complication of underlying venous thrombosis and most often arises from the deep veins of the lower extremities. The thromboembolic event is difficult to diagnose clinically and carries significant morbidity and mortality. Treatment with anticoagulation also has risks. Thus accurate diagnosis is important. A normal perfusion lung scan excludes major pulmonary emboli. Lung perfusion scintigraphy provides high sensitivity for interrupted blood flow but lacks specificity for embolic vascular occlusion. Ventilation scintigraphy is sensitive for obstructive pulmonary disease and improves specificity for PE when combined with the perfusion scan. Several retrospective studies have established probability levels for PE on the basis of certain ventilation, perfusion, and chest x-ray patterns. These results have high positive and negative predictive value and directly affect patient management. The first large prospective study on PE has just been completed. The results of this study should more clearly define the role for ventilation-perfusion scintigraphy in PE.

[Comparison of radionuclide venography with roentgen phlebography]

The authors evaluated a group of 78 patients where in addition to radionuclide venography (RNV) also X-ray phlebography was used (RTGF) within a time interval of not more than 72 hours. The results of 102 examinations were compared, 276 areas were correlated at six different sites. Agreement was recorded in 249 instances (90%), a false negative finding in 23 (8%) and a false positive finding in 4 (2%). Sensitivity was low in the area of the calf (55%), high in the femoral area, iliac area and in the area of the inferior vena cava (92-100%). The specificity was in all areas, incl. the calf, relatively high (94-100%). The investigation revealed the disadvantages of RNV--a low reliability in the area of the calf, the impossibility to detect small and parietal thrombi, the inability to assess the "activity and age" of the thrombus, the more difficult interpretation in insufficiency of venous perforators, and advantages of RNV--a great reliability at higher parts of the venous system and after administration of radiopharmaceutical preparations (RF) into peripheral veins, the possibility of simultaneous examination of pulmonary perfusion without further administration of RF, a low failure rate of intravenous administration of RF (less than 2%); RF do not irritate the venous endothelium and therefore thrombosis cannot develop; in case of paravenous escape of RF local inflammations do not develop, the radiation load is low, there is a small probability of allergic reactions, the method is non-invasive, it can be frequently repeated and used for the follow-up of treatment.

[Use of the Kimray-Greenfield filter in the prevention of pulmonary embolism. Personal experience]

Personal experience in the use of intra-caval filters in the prevention of pulmonary embolisms is reported. The advantages and the indications for positioning of the K.G. filter are analysed on the basis of a series of 31 patients operated on with this method.

Early image acquisition after administration of indium-111 platelets in clinically suspected deep venous thrombosis

Indium-111 platelet scintigraphy accurately detects acute deep venous thrombosis in asymptomatic high-risk patients and may be used as a surveillance test. However, its value in symptomatic patients and its accuracy early after platelet injection are not satisfactorily established. The latter is important for timely institution of therapy. Accordingly, 65 patients (67 limbs) with suspected deep venous thrombosis (symptom duration 8 +/- 10 days, mean +/- standard deviation) were prospectively studied with platelet scintigraphy and contrast venography. Platelets were labeled with 405 +/- 101 mCi indium-111 oxine. The labeling efficiency was 80 +/- 10%. All images were acquired within 120 minutes after intravenous administration of the platelet suspension. Both platelet scintigraphy and venography were interpreted independently by 2 blinded observers (for each technique). Five separate analyses were performed. Each scintigraphic reader was compared to each venographic reader. A fifth analysis--consisting of readings with blinded agreement of both readings of the platelet scans and both readings of the venograms--was performed. Interobserver agreement was 92% for venography and 79% for scintigraphy. Excluding anticoagulated patients, the sensitivity of platelet scintigraphy was between 38 and 46% and the specificity was between 92 and 100%. Thus, early imaging of labeled platelets for the diagnosis of symptomatic deep venous thrombosis carries a high specificity but a much lower sensitivity. It is speculated that the low sensitivity is related to the inactivity of the thrombus. This may suggest that early imaging will only be useful in patients whose symptoms are of recent onset.

[Diagnosis of postpartum complications using CT and MRT]

Severe puerperal infections, iliacal and ovarian vein thrombosis are post-partum complications which are potentially life-threatening. They require prompt medical treatment. CT and MR enable diagnosis by noninvasive methods.

Duplex venous scanning for the prospective surveillance of perioperative venous thrombosis

A total of 361 patients undergoing a variety of major neurosurgical procedures were entered into a prospective surveillance program using duplex ultrasound scanning for detection of perioperative deep venous thrombosis (DVT). All patients had duplex scans of the major veins of both legs preoperatively, on the third and seventh postoperative days, and at weekly intervals thereafter if hospitalized. All patients received elastic stocking and intermittent mechanical calf compression. Perioperative DVT was diagnosed by duplex scan in 17 cases (4.7%); 2 cases were present preoperatively and the remaining 15 cases developed after surgery. Venography detected only one false-positive scan in this series. One patient with DVT died, but the postmortem examination revealed no pulmonary embolism. The results of serial venous scans were normal in 344 cases. There were no in-hospital pulmonary embolisms in any patient with normal venous scan results. Two patients (0.6%) with normal serial scan results had fatal pulmonary embolism 1 and 3 weeks after discharge. Duplex venous scanning was useful for prospective DVT surveillance of a high-risk group. The overall incidence of DVT (4.7%) is below that expected in such patients, suggesting the effectiveness of the program of prophylaxis. Scan results were reliable for therapeutic decisions and did not jeopardize patient safety.

Digital venography of the lower extremity

A digital 33-cm fluoroscopic system equipped with conventional spot-film and digital or video hard-copy capabilities was evaluated for its usefulness in diagnosing deep venous thrombosis of the lower extremities. The impact of different fluoroscopic field sizes, spatial resolution, and contrast variance was measured by using phantoms. The results indicate that the physical characteristics of the digital system are acceptable for lower-extremity venography. Digital fluoroscopic hard copy was compared with conventional spot films in 22 examinations. The digital examinations were as accurate as the conventional examinations. Procedure time, exposure to radiation, film costs, and repeated injections of contrast medium because of errors in exposure were reduced with the digital method. The need for extra technologists was eliminated. The advantages of digital radiographic displays, postprocessing, storage, and transmission were maximized. Digital fluoroscopic examinations were as accurate as conventional spot films and were found to have many advantages.

Pulmonary embolism during venography: report of a rare complication

Fortuitous radiologic documentation of a migrating thrombus during phlebography resulting in massive pulmonary embolus and cardiopulmonary collapse is demonstrated. This is a rare occurrence that has been infrequently documented and published.

[The side effects of phlebography of the lower extremities using iohexol. A prospective study]

In this prospective study 463 consecutive outpatients, who had undergone phlebography because of clinically suspected deep venous thrombosis (DVT) were examined with clinical follow-up and impedance plethysmography to evaluate the rate of contrast media complications. Seventy-nine patients had immediate and mild side effects, and one had moderate side effects (bronchospasm); no patient suffered from severe life-threatening conditions. There was only one case of DVT which occurred after an initially negative phlebography. In a subgroup of 40 patients, who underwent iodine-125-fibrinogen scanning after phlebography, the study was positive in 9 cases. None of them presented with any evidence of DVT at follow-up phlebography. Contrast phlebography with iohexol is a safe and comfortable procedure. Low-osmolality nonionic contrast media are well tolerated by the patient.

Immunoscintigraphic detection of venous thrombosis of the lower extremities by means of human antifibrin monoclonal antibodies labeled with 111In

A new monoclonal antibody specific for the beta-chain of human fibrin (C22A) and labeled with 111In has been obtained and successfully used in rabbits and dogs for the in vivo detection of venous thrombosis. Studies in humans are currently ongoing. In order to assess the diagnostic value of 111In-antifibrin for the detection of venous thrombosis of the lower extremities, the authors investigated 25 consecutive patients. Ten patients had clinical and instrumental (contrast phlebography and duplex scanning) evidence of acute deep venous thrombosis (DVT), 3 had a long-standing DVT with relapsing episodes of swelling and pain, 5 had superficial venous thrombosis, and the remaining 7 had no signs of thrombosis at all. Twenty patients were being treated with heparin. All patients received 111In-antifibrin at the dose of 74 MBq IV and were scanned with a large field of view gamma camera coupled with a high-energy, parallel-hole collimator at 30 minutes and three, six, and twenty-four hours postinjection. Only the persistence of an abnormal uptake at twenty-four hours confirmed by two observers at visual inspection was considered as positive. A positive result was obtained in 9 of 10 DVT patients (90% sensitivity) and in all SVT patients. The single DVT patient with a negative 111In-antifibrin test had the longest interval between scintigraphy and onset of symptoms (fifty-five days). Thus, the age of thrombi represented a substantial limitation for the test. A false-positive result was obtained in a single SVT patient, in whom also a deep involvement, unconfirmed by phlebography, was suspected (91.6% specificity).(ABSTRACT TRUNCATED AT 250 WORDS)

Deep vein thrombosis in an adolescent

We report an unusual case of deep vein thrombosis following minor trauma in an adolescent who presented with a swollen, tender, lower extremity. Work-up consisted of a venogram which demonstrated occlusion of the deep venous system in the proximal leg. The patient was hospitalized for intravenous heparin followed by oral anticoagulation therapy. The problem of deep venous thrombosis in adolescents and the approach to diagnosis are discussed.

Use of thermography in the diagnosis of deep vein thrombosis

We attempted to evaluate the use of liquid crystal thermography (LCT) as a screening tool in the detection of deep venous thrombosis (DVT) in the lower extremities. Forty patients were examined with LCT and venography. A venogram was used as the standard by which the LCT results were compared. Liquid crystal thermography had a sensitivity of 70% and a specificity of 50%, and it was found not to have a greater accuracy than clinical examination.

[Liquid-crystal-contact-thermography (LCCT)--a new diagnostic method for determination of skin circulation. Results of 300 studies]

In cases where minor differences in skin temperature are of importance, LCCT can be used. Furthermore LCCT can be used to document the malperfusion of the leg and postoperative flow control of a bypass after revascularization, as well as determination of the site of amputation in cases where revascularization is not possible. General surgery, traumatology: LCCT is well suited as a screening method in the diagnosis of deep venous thrombosis. Our clinical trial with more than 300 patients documents the simple, non-invasive use of LCCT. More than 80 patients had parallel ascending venography performed in order to document sensitivity and specificity of LCCT. We found LCCT to have a sensitivity to 95% and a specificity of 86% when compared to venography. LCCT must be performed by a physician to rule out other pathogenic factors leading to either a rise or a fall in skin temperature. As LCCT is an absolutely non-invasive method and having a high sensitivity and specificity it is well suited as screening method in the diagnosis of deep venous thrombosis. LCCT can be recommended to all angiologic wards and certainly to very surgical clinic, as the early recognition or exclusion of postoperative deep venous thrombosis is its main goal.