Noninvasive venous testing in the diagnosis of pulmonary embolism: The impact on decisionmaking

Purpose: To characterize the use and utility of lower extremity noninvasive venous testing (NIVT) in the diagnosis of pulmonary embolism (PE).Methods: The study is a retrospective case series of consecutive patients in whom PE was suspected who were referred to a large, urban tertiary care center for NIVT. The main outcome measures of the study were the rate of positive results of NIVT, the amount of new information provided by NIVT, and the frequency of management changes that were attributable to NIVT.Results: Forty-one of 450 patients (9%) had deep venous thrombosis (DVT) by NIVT. The prevalence of DVT by NIVT among patients not evaluated by ventilation/perfusion (V/Q) scanning was 8%. The prevalence of DVT by NIVT among patients with a high-probability V/Q scan result before NIVT was 39%, but no management decisions in this group were based on a positive NIVT result and only two decisions were based on negative NIVT results. The prevalence of DVT according to NIVT among patients who had a negative “diagnostic” (low, or very low probability, or normal) result of V/Q scan before NIVT was 2%. The overall frequency of management changes attributed to NIVT was only 2.5%. In the remaining 97% of patients, management was determined by the result of V/Q scanning or of subsequent pulmonary arteriography.Conclusions: In patients in whom PE is suspected, results of NIVT are usually negative for acute DVT. Management decisions are almost always based on V/Q scan or results of pulmonary arteriography and not on NIVT. The utility of NIVT to identify DVT in these patients appears limited, and a more selective approach to its application for the diagnosis of PE should be considered. (J Vasc Surg 1997 26:757-63.)     

Role of venous duplex scanning in patients with suspected pulmonary embolism

Purpose: We examined the use of venous duplex scanning (VDS) in the diagnosis of pulmonary embolism (PE) at our institution.Methods: Patients undergoing lower extremity VDS from October 1988 through June 1995 were cross-referenced with those who underwent ventilation perfusion (V/Q) scans and pulmonary angiography (PA) for PE.Results: A total of 664 of 3534 VDS were for “rule out PE.” Deep venous thrombosis was found in 13%. A total of 256 VDS were in conjunction with V/Q scans in 249 patients, with only 8% undergoing PA. Deep venous thrombosis was present in 18% for those with both V/Q and VDS compared with 10% ( p < 0.01) for those with VDS as the sole study. The order in which V/Q, VDS, and PA were obtained and the relationship of positive studies was examined.Conclusion: We found no pattern to the sequence of tests ordered. V/Q scan rather than VDS should be the first study in the evaluation of PE. PE was diagnosed or excluded in nearly one third of patients based on V/Q as the initial study. A total of 29% of VDS could have been avoided. Treatment could be determined on the basis of VDS as the initial study in only 13%. We found only 14% incidence of positive PA in patients with nondiagnostic V/Q scans. We advocate judicious use of diagnostic tests in a stepwise fashion to appropriately treat patients with suspected PE. (J Vasc Surg 1996;24:768-73.)     

Is venous duplex imaging an appropriate initial screening test for patients with suspected pulmonary embolism?

Noninvasive tests for deep venous thrombosis (DVT) are helpful in evaluating patients with suspected pulmonary embolism (PE) who have non-high-probability ventilation/perfusion (V/Q) lung scans. Based on the enthusiasm for these noninvasive tests, venous duplex imaging (VDI) has evolved as the initial screening test for patients with clinically suspected PE in some centers. This study evaluates the utility of VDI as the initial test in a diagnostic algorithm for patients with suspected PE. A total of 306 consecutive patients who underwent VDI as the initial screening test for clinically suspected PE during the past 24 months were reviewed; 121 patients were subsequently evaluated with V/Q scans and 20 underwent pulmonary arteriography. VDI demonstrated DVT in 10% (23/216), with 7% (22/306) having proximal DVT and 3% (9/306) having isolated calf DVT. In 25 patients with unilateral leg symptoms, DVT was found in 40% (10/25); however, among the 281 without unilateral leg symptoms, results of VDI were abnormal in only 5% (15/281). V/Q scans were obtained in 40% (121/306), with only 16% (19/121) of scans showing a high probability of PE. DVT was found in 25% (5/19) of patients with high-probability V/Q scans and in 25% (26/102) with non-high-probability scans. In patients with clinically suspected PE the incidence of detectable infrainguinal DVT is low. VDI appears to be a reasonable initial screening test in patients with clinically suspected PE and unilateral leg symptoms. However, in patients without unilateral leg symptoms, the diagnostic yield is low and an alternative diagnostic approach appears justified.Supported in part by NIH grant 1 K07HL02658-01.Presented at the Twentieth Annual Meeting of the Peripheral Vascular Surgery Society, New Orleans, La., June 10, 1995.     

Usefulness of arterial blood gas analysis and D-dimer measurement in the assessment of pulmonary embolism after orthopedic surgery

Background Deep venous thrombosis (DVT) and pulmonary embolism (PE) after spinal or lower extremity surgery are well recognized as common complications. Since 1995 we have investigated the incidence of PE after orthopedic surgery using ventilation-perfusion (V/Q) lung scans, and the prevalence of PE was about 10%. With a view to detecting early-stage PE by simple examinations, we evaluated the use of both the blood gas analysis and the D-dimer measurement after spinal or lower extremity surgery. Methods Altogether, 85 patients who underwent spinal or lower extremity surgery were eligible for the study. Pneumatic sequential leg compression devices (PSLCDs) were utilized continuously both intra- and postoperatively. Arterial blood gas analysis and D-dimer measurement were performed pre- and postoperatively on days 3 and 7. We set lung scan criteria as follows: postoperative decrease in Pao2 (ΔPao2) by ≥10 torr (group G), postoperative D-dimer of ≥1μg/ml (group D), or both. Patients with the criteria went on to undergo lung scans, and PE was diagnosed by the existence of any mismatch between ventilation-perfusion (V/Q) lung scans. Results A total of 44 (51.8%) patients met the lung scan criteria and underwent perfusion lung scans, 10 (11.7%) of whom were diagnosed as PE. In groups G and D, about 30% showed PE. Moreover, six (85.7%) of the seven patients with both criteria showed a significant increase (83.7%) in the prevalence of PE. Conclusions Patients with the above criteria showed a high prevalence of PE. Moreover, 10 (11.7%) of the 85 patients were diagnosed as having PE, which corresponded to the prevalence in our former studies where lung scans were performed in all patients. The blood gas analysis and the D-dimer measurement may be utilized as the first screening examinations.     

The current state of practice in the diagnosis of venous thromboembolism at an academic medical center

Evidence-based guidelines for the diagnosis of venous thromboembolism (VTE) have been recommended, yet the adoption of such guidelines into daily practice is unknown. The purpose of this study was to describe the current practices in the diagnosis of VTE. Medical records of 1161 adult patients who underwent lower extremity venous duplex scans (VDS), chest computerized tomographic (CT) angiography, or ventilation and perfusion (V/Q) scans during a 6-month period were retrospectively reviewed in an academic medical center. Patients who were first diagnosed by CT or V/Q scan still underwent a VDS. Nine patients at high risk had incomplete CT scans, yet no further tests were performed. Five pregnant patients had CT scans as the initial test instead of being screened with VDS or V/Q scanning. Inappropriate use of imaging tests was documented. The recommended guidelines of using clinical probability and D-dimer as the initial screening tests for VTE diagnosis were underused.     

Role of spiral volumetric computed tomographic scanning in the assessment of patients with clinical suspicion of pulmonary embolism and an abnormal ventilation/perfusion lung scan.

BACKGROUND: A study was carried out to evaluate the potential place of spiral volumetric computed tomography (SVCT) in the diagnostic strategy for pulmonary embolism. METHODS: In a prospective study 249 patients with clinical suspicion of pulmonary embolism were evaluated with various imaging techniques. In all patients a ventilation/perfusion (V/Q) scan was performed. Seventy seven patients with an abnormal V/Q scan underwent SVCT. Pulmonary angiography was then performed in all 42 patients with a non-diagnostic V/Q scan and in three patients with a high probability V/Q scan without emboli on the SVCT scan. Patients with an abnormal perfusion scan also underwent ultrasonography of the legs for the detection of deep vein thrombosis. RESULTS: One hundred and seventy two patients (69%) had a normal V/Q scan. Forty two patients (17%) had a non-diagnostic V/Q scan, and in five of these patients pulmonary emboli were found both by SVCT and pulmonary angiography. In one patient, although SVCT showed no emboli, the angiogram was positive for pulmonary embolism. In one of the 42 patients the SVCT scan showed an embolus which was not confirmed by pulmonary angiography. The other 35 patients showed no sign of emboli. Thirty five patients (14%) had a high probability V/Q scan, and in 32 patients emboli were seen on SVCT images. Two patients had both a negative SVCT scan and a negative pulmonary angiogram. In one who had an inconclusive SVCT scan pulmonary angiography was positive. The sensitivity for pulmonary embolism was 95% and the specificity 97%; the positive and negative predicted values of SVCT were 97% and 97%, respectively. CONCLUSIONS: SVCT is a relatively noninvasive test for pulmonary embolism which is both sensitive and specific and which may serve as an alternative to ventilation scintigraphy and possibly to pulmonary angiography in the diagnostic strategy for pulmonary embolism.     

Asymptomatic pulmonary embolism in patients with deep vein thrombosis. Is it useful to take a lung scan to rule out this condition?

One hundred and sixteen patients with proximal deep venous thrombosis (DVT) confirmed venographically had perfusion and ventilation lung scans performed 48 hours after admission to assess the incidence of asymptomatic pulmonary embolism (PE). Sixty-six patients had normal lung scans, 29 had high-probability defects suggestive of PE, and 21 had indeterminate-probability of PE. Chest X-ray, electrocardiogram and arterial blood gases were of no value in assessing the lung scan results. Six out of 29 patients with a baseline lung scan of high probability of PE experienced acute signs and/or symptoms suggestive of pulmonary embolism while on heparin therapy. A repeated scan this time did not disclose new perfusion defects in any patients. In the absence of a baseline study, these scans may be interpreted as demonstrating pulmonary embolism on treatment and lead to unnecessary caval interruption procedures for failed heparin therapy.     

Factor V Leiden and Postoperative Deep Vein Thrombosis in Patients Undergoing Open Roux-en-Y Gastric Bypass Surgery

Background: Patients undergoing bariatric surgery are at risk for deep venous thrombosis (DVT) and fatal pulmonary embolus. In the presence of genetic hypercoagulable disorders, accepted methods of DVT prophylaxis utilizing sequential compression devices and subcutaneous unfractionated heparin may not be adequate to prevent DVT or fatal PE. Methods and Results: 3 morbidly obese patients are described who underwent open Roux-en-y gastric bypass and either had a previous diagnosis of Factor V Leiden or developed thrombosis in the presence of standard prophylaxis. Each was found to have the most common point mutation for Factor V Leiden, R506Q. All 3 patients had prophylactic inferior vena caval filters placed to prevent recurrent PE. Conclusion: The presence of venous thromboembolism either without known risk factors or in the presence of standard perioperative prophylaxis for DVT should warrant a hypercoagulable work-up. Inferior vena caval filter placement is indicated in the presence of a hypercoagulable disorder prior to surgical intervention in the morbidly obese population. The recent literature is reviewed.     

Diagnosis of pulmonary embolism with various imaging modalities

Pulmonary embolism (PE) is a major health concern that affects approximately 600,000 new patients annually. The diagnosis of PE can be difficult to make, and several imaging studies have been developed to aid in this process. Initial evaluation involves the acquisition of a chest radiograph. Findings on radiography, however, are often non-specific. The gold-standard study historically has been pulmonary angiography, with increasing diagnostic yield since the implementation of digital subtraction technology. This is an invasive procedure, however, but the incidence of major complications is low. Less invasive modalities have been developed and include ventilation-perfusion lung scans. These are used as one of the initial screening tests in evaluation of patients with suspected PE. The presence of a high-probability scan usually indicates the presence of a PE, although few patients have high probability scans. The test is significantly affected by underlying pulmonary disease or previous PE. Given this, ventilation-perfusion lung scans are limited as a primary diagnostic tool in the evaluation of suspected PE. Helical computed tomography (CT) is currently under much scrutiny as a diagnostic tool for PE. Currently a prospective, multicenter trial evaluating its efficacy (PIOPED II) has been initiated, but the results are pending. Preliminary reports suggest the helical CT and venous phase CT may become a first line study in patient evaluation. The diagnosis of PE is challenging and several imaging modalities are currently used to assist the clinician. Currently, multiple modalities are often required to make the diagnosis. With the advent of new technology and improved imaging techniques, the diagnosis of PE will become easier.     

Pulmonary embolism

Pulmonary embolism (PE) is a common problem for which prompt diagnosis and treatment is essential to minimize mortality. The clinical presentation is more variable than sudden dyspnea and chest pain, especially in the critical care patient. Recognition of venous thromboembolic (VTE) risk factors can help develop a good clinical suspicion for PE. A wide range of diagnostic tests are available to the clinician. The ventilation/perfusion scan, pulmonary arteriogram, and lower extremity investigations are still important for diagnosis. Other noninvasive tests such as spiral CT with venography, echocardiography, and D-dimers are becoming more accepted. Heparin is the mainstay of PE therapy, but thrombolytic treatment may be lifesaving in the unstable patient. VTE prophylaxis should be considered in all post-operative or critical care patients.     

Can ventilation-perfusion scans accurately diagnose acute pulmonary embolism?

To examine the accuracy of ventilation-perfusion (V/Q) scanning, we retrospectively reviewed pulmonary angiograms and V/Q scans from 150 patients clinically suspected of having pulmonary embolism. Pulmonary emboli were documented by angiography in 56 patients (37%). In seven patients V/Q scans were interpreted as being normal and these seven patients were angiographically negative for emboli. The remainder of the scans were classified as showing a low, moderate, or high probability of emboli, or as indeterminate scans. Among these four abnormal classifications, pulmonary angiography demonstrated emboli in 13.6%, 62.5%, 85.7%, and 18.4% of these patients, respectively. An analysis of these data demonstrates that an unacceptably high error rate would result if V/Q scans alone were relied upon to establish the presence or absence of pulmonary emboli. In view of the high mortality that results when pulmonary emboli are untreated and the relatively low mortality and morbidity of pulmonary angiography, angiography remains an essential diagnostic procedure in patients suspected of having pulmonary embolism.     

Preoperative three-dimensional reconstruction of the heart and great vessels in patients with congenital heart disease. Technique and initial results

Magnetic resonance images have been obtained preoperatively in six patients with congenital heart disease. Contiguous sequences of electrocardiogram-triggered spin-echo images have been reconstructed in three-dimensional form to define the size and anatomic relationships to the great vessels and internal cardiac structures. Findings of magnetic resonance imaging were corroborated by angiographic and sector-scan echocardiographic studies and at operation. Individual scan slices were manually edited to separate the heart and great vessels from the blood within them and from extracardiac structures. Surface reconstruction software originally developed for craniofacial and orthopedic surgical planning was adapted for processing of cardiac magnetic resonance image sequences. Preoperative three-dimensional magnetic resonance imaging reconstructions were obtained in patients with aortic coarctation with ventricular septal defect, hypoplastic left ventricle, pulmonary artery atresia with ventricular septal defect, atrial septal defect, partial atrioventricular canal defect with anomalous pulmonary venous drainage, and tetralogy of Fallot with peripheral pulmonary artery stenosis. The reconstructions showed anatomic findings consistent with two-dimensional magnetic resonance imaging, echocardiography, cineangiography, and intraoperative findings. The three-dimensional images have a format that is familiar and consistent with the gross intraoperative appearance of the heart and great vessels. These three-dimensional images can facilitate the interpretation of magnetic resonance scan findings for cardiac surgeons without the sacrifice of significant clinical information.     

Usefulness of D-dimer, blood gas, and respiratory rate measurements for excluding pulmonary embolism

BACKGROUND: A study was undertaken to assess the usefulness of the SimpliRED D-dimer test, arterial oxygen tension, and respiratory rate measurement for excluding pulmonary embolism (PE) and venous thromboembolism (VTE). METHODS: Lung scans were performed in 517 consecutive medical inpatients with suspected acute PE over a one year period. Predetermined end points for objectively diagnosed PE in order of precedence were (1) a post mortem diagnosis, (2) a positive pulmonary angiogram, (3) a high probability ventilation perfusion lung scan when the pretest probability was also high, and (4) the unanimous opinion of an adjudication committee. Deep vein thrombosis (DVT) was diagnosed by standard ultrasound and venography. RESULTS: A total of 40 cases of PE and 37 cases of DVT were objectively diagnosed. The predictive value of a negative SimpliRED test for excluding objectively diagnosed PE was 0.99 (error rate 2/249), that of PaO2 of > or = 80 mm Hg (10.7 kPa) was 0.97 (error rate 5/160), and that of a respiratory rate of < or = 20/min was 0.95 (error rate 14/308). The best combination of findings for excluding PE was a negative SimpliRED test and PaO2 > or = 80 mm Hg, which gave a predictive value of 1.0 (error rate 0/93). The predictive value of a negative SimpliRED test for excluding VTE was 0.98 (error rate 5/249). CONCLUSIONS: All three of these observations are helpful in excluding PE. When any two parameters were normal, PE was very unlikely. In patients with a negative SimpliRED test and PaO2 of > or = 80 mm Hg a lung scan is usually unnecessary. Application of this approach for triage in the preliminary assessment of suspected PE could lead to a reduced rate of false positive diagnoses and considerable resource savings.     

Impact of Medicare denials on noninvasive vascular diagnostic testing.

PURPOSE: The purpose of this study was to evaluate the impact of Medicare coverage limitations and claim denials on noninvasive vascular diagnostic testing. METHODS: All Medicare claims for noninvasive vascular diagnostic studies from January 1, 1999, to December 31, 1999, were identified from the hospital billing database according to Current Procedural Terminology codes for carotid artery duplex ultrasound scan, venous duplex ultrasound scan, and lower-extremity arterial Doppler scan. Reasons for Medicare denial of payment for these tests were reviewed and a cost analysis was performed. RESULTS: During the 1-year period, there were 1096 noninvasive vascular diagnostic studies performed on Medicare patients. Of these 1096 tests, 176 (16.1%) were denied by Medicare (19.6% of 408 carotid duplex ultrasound scans, 16.8% of 345 venous duplex ultrasound scans, and 11.1% of 343 lower-extremity arterial Doppler scans). Of the noninvasive vascular tests denied by Medicare, an abnormal result was present in 72.5% of carotid duplex ultrasound scans, 32.8% of venous duplex ultrasound scans, and 78.9% of lower-extremity arterial Doppler scans. Overall, 88.1% of all initially denied claims (N = 176) were ultimately reimbursed by Medicare after resubmission, including 77.1% of the 118 claims denied based on compliance rules for "medical necessity." CONCLUSION: Because of coverage limitations, Medicare denials of noninvasive vascular diagnostic tests can lead to potential uncompensated physician and hospital technical fees if denied claims are unrecognized. Vascular laboratories performing these tests need to review compliance with Medicare guidelines. Improvements may need to be made at both the provider and Medicare carrier levels in obtaining reimbursement for appropriately ordered noninvasive vascular diagnostic studies.     

The role of integrated positron emission tomography-computerized tomography in evaluating and staging patients with non-small cell lung cancer

The stage of non-small cell lung cancer (NSCLC) determines that the treatment strategy and proper staging lead to improved survival. Integrated positron emission tomography/computerized tomography (CT) scan provides more accurate staging and better targets for biopsy than traditional methods such as CT scans of the chest and upper abdomen, bone scans, and magnetic resonance imaging scans. Integrated positron emission tomography/CT is the best initial test for an indeterminate pulmonary nodule that is 8 mm or greater; for the noninvasive staging of patients with NSCLC, it is the only test that produces a quantitative assessment of an NSCLC's virulence or biologic aggressiveness in a particular patient and is the best tool for restaging patients after radiation and and/or chemotherapy. Finally, its use as a tool for postoperative surveillance is under study.     

The limitations of impedance plethysmography in the diagnosis of acute deep venous thrombosis

We reviewed our experience with impedance plethysmography (IPG) and duplex scanning in the diagnosis of acute deep venous thrombosis (DVT) to determine their respective accuracy and current role in our noninvasive vascular laboratory. During a recent 22-month period 1776 patients were evaluated in our laboratory for DVT. Sixty patients (64 limbs) underwent ascending venography within 48 hours of testing (49 limbs were evaluated by all three modalities). With the venograms used as the reference standard, B-mode scanning correctly identified the presence of acute thrombus in 24 of 27 limbs (88.8%) and the absence of thrombus in 31 of 34 limbs (91.2%), for an overall accuracy of 90.6%. IPG alone was less sensitive (75%) and less specific (44.8%), with an overall accuracy of only 57.1%. Twenty-eight IPGs were performed on patients with negative venous scans. Two positive IPGs were the result of chronic venous occlusion and two others detected clinically significant isolated iliac vein thrombi, but 13 patients had false positive IPGs. One false negative IPG occurred. The difference in the sensitivity of scan alone vs scan plus IPG was not significant (chi 2 = 0.045; difference not significant), but the decrease in specificity was chi 2 = 17.3; p less than 0.001). The rarity of isolated iliac vein thrombosis and the high false positive rate for IPG do not justify its continued use if B-mode venous scanning is available. Although positive scan results may be used confidently to institute therapy without the need for venography, in high-risk patients with a strong clinical suspicion of proximal DVT despite a negative scan venography should be obtained before withholding anticoagulation.     

Acute calf vein thrombosis: outcomes and implications

The purpose of this study was to define the incidence of and outcomes associated with isolated acute calf vein thrombosis (CVT). From 11/95 through 6/97, 3096 patients underwent lower extremity venous duplex testing in a hospital-based vascular laboratory in which bilateral tibial and peroneal vein imaging were standard components of the venous duplex examination. CVT was present in 118 patients (3.8%), and 339 patients (10.9%) had acute proximal deep venous thrombosis (PDVT). Patients with CVT were 56.4+/-17.2 years of age (range, 18-92). Approximately 25 per cent with CVT had cancer (n = 30). Of the 18 patients with CVT who underwent ventilation-perfusion (V/Q) lung scanning, 56 per cent (n = 10) had high-probability scans. Venous duplex reports for those with CVT recommended follow-up venous duplex examination, which was done in 60 per cent (n = 71) of patients. Of the 71 patients with CVT who underwent follow-up testing, 15.5 per cent (n = 11) progressed to PDVT. The incidence of progression to deep venous thrombosis was 25 per cent (9 of 36) in those receiving anticoagulants at the time of initial venous duplex examination versus 5.7 per cent (2 of 35) in those not receiving anticoagulants (P = 0.046). With progression to PDVT, patients were more likely to have cancer (35% versus 7.8%; P = 0.009), more likely to have high-probability V/Q scans (36% versus 6.7%; P = 0.017), and more likely to die (27% versus 1.7%; P = 0.011) during follow-up. CVT was less common than proximal deep vein thrombosis and was also associated with pulmonary embolism. Progression of CVT was an adverse clinical event associated with greater chance of pulmonary embolism and death.     

Deep vein thrombosis and pulmonary emboli in neurosurgical patients: a review

This review examines the incidence, natural history, diagnosis, prophylaxis, and management of deep vein thrombosis (DVT) and pulmonary embolism (PE) in neurosurgical patients. Recent studies estimate the incidence of postoperative DVT detected by fibrinogen scanning in neurosurgical patients to be 29% to 43%. Specific factors that enhance the risk of venous thromboembolism include previous DVT, surgery, immobilization, advanced age, obesity, limb weakness, heart failure, and lower extremity trauma. Clinical diagnosis of venous thromboembolism is unreliable but can be augmented by noninvasive screening tests such as iodine-125-fibrinogen scanning, Doppler ultrasonography, and impedance plethysmography. As prophylactic measures, mini-dose heparin and external pneumatic compression of the legs have decreased the incidence of DVT in clinical studies of neurosurgical patients. However, no prophylactic measure has been convincingly shown to prevent PE in neurosurgical patients. Thrombi involving the popliteal, deep femoral, and iliac veins appear most likely to cause significant PE. Anticoagulation therapy constitutes standard management of DVT and PE; however, in neurosurgical patients the potential for precipitating intracranial or intraspinal hemorrhage may necessitate vena caval interruption. This appears to be an effective alternative to anticoagulation.     

A prospective trial evaluating a standard approach to reoperation for missed parathyroid adenoma.

OBJECTIVES: The authors evaluate the results of preoperative imaging protocols and surgical re-exploration in a series of patients with missed parathyroid adenomas after failed procedures for primary hyperparathyroidism. BACKGROUND: The success rate is lower and the complication rate is increased in patients undergoing reoperation for primary hyperparathyroidism compared with initial procedures. Scarring and distortion of tissue planes plus the potential for ectopic gland location leads to this worsened outcome. METHODS: Two hundred eighty-eight consecutive patients with persistent/recurrent hyperparathyroidism were treated at a single institution after a failed procedure or procedures at outside institutions. Two hundred twenty-two of these patients (77%) were believed to have a missed single adenoma, and these patients underwent 228 operations and 227 preoperative work-ups. Preoperative evaluation consisted of a combination of four noninvasive imaging studies--neck ultrasound, nuclear medicine scan, neck and mediastinal computed tomography scan, and neck and mediastinal magnetic resonance imaging. Based on the noninvasive testing alone, 27% patients underwent surgery whereas the other patients underwent invasive studies, including selective angiography (58%), selective venous sampling for parathyroid hormone (43%), or percutaneous aspiration of suspicious lesions (15%). RESULTS: Abnormal parathyroid adenomas were found in 209 of 222 initial procedures and 6 of 6 second procedures, with an overall success rate in terms of resolution of hypercalcemia in 97% (215/222) of patients. The single most common site of missed adenoma glands was in the tracheal-esophageal groove in the posterior superior mediastinum (27%). The most common ectopic sites for parathyroid adenomas are thymus (17%), intrathyroidal (10%), undescended glands (8.6%), carotid sheath (3.6%), and the retroesophageal space (3.2%). The most sensitive and specific noninvasive imaging test is the sestamibi subtraction scan, with 67% true-positive and no false-positive results. The rate of true-positive and false-positive results for ultrasound, computed tomography, magnetic resonance imaging, and technetium thallium scans were 48%/21%, 52%/16%, 48%/14% and 42%/8%, respectively. The incidence of injury to the recurrent laryngeal nerve was 1.3%. CONCLUSIONS: A single missed parathyroid adenoma is the most common cause for a failed initial parathyroid operation. Appropriate use of preoperative imaging tests and knowledge of the potential location or parathyroid adenomas can lead to very high cure rates with minimal morbidity.     

Psoas abscess in children

In children, psoas abscess does not head the list in the differential diagnosis of the child who presents with a limp or lower abdominal pain. Therefore, the road to this diagnosis can be long and complicated leading to numerous studies and specialty consultations. Over a 7-year period, seven psoas abscesses have been drained surgically. All were Staphylococcal though one was mixed. In each case, the original admitting diagnosis was that of septic arthritis of the hip. In general, this diagnosis was ruled out by negative hip aspirations and bone scans. Often, the severity of symptoms led to persistent evaluation with noninvasive tests such as gallium scan, intravenous pyelogram, or barium enema. Though these tests were often suggestive, a positive ultrasound or CT scan was the key studies diagnostic enough to warrant surgical exploration and drainage. During this time period, there have been no negative explorations for psoas abscess. Upon surgical drainage, all patients improved, with subsequent recovery of hip function. The child who presents with a limp or painful hip should be considered for ultrasonography or computerized tomography once hip pathology is ruled out. We feel that the results of other tests such as gallium scan, IVP, or barium enema are not sufficiently specific to indicate surgery.