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The purpose of this study was: (1) to determine the prevalence of deep vein thrombosis (DVT) after the use of a mechanical compression device only, without pharmacological thromboprophylaxis; (2) to investigate the factors associated with DVT; and (3) to investigate the natural course of DVT and PE. We reviewed consecutive series of 874 patients (1434 knees) who received treatment with a mechanical compression device only for prevention of DVT after primary TKA. The prevalence of DVT was 6.6% (94 of 1434 knees). Proximal thrombi were found in 6 of 1434 knees (0.4%). No patient had PE on perfusion lung scans. Further sonograms and venograms for the patients with thrombi at 6 months after the operation revealed that all thrombi were resolved.

Pulmonary hypertension (PH): mean pulmonary arterial pressure (mPAP) ≥ 25 mm Hg on right heart catheterization at rest. Pulmonary arterial hypertension (PAH): mPAP ≥ 25 mm Hg, pulmonary capillary wedge pressure (PCWP) ≤ 15 mm Hg and pulmonary vascular resistances (PVR) >3 Wood units. Patients with compatible symptoms (exertional dyspnea, syncopes, signes of right heart failure) can show signs of PH on cardiac echography and therefore need to be investigated in search of the cause of PH. After ruling out the frequent causes of PH (left heart and chronic respiratory diseases), the V/Q lung scan is used to screen for patients with post-embolic PH, that need to be further investigated hemodynamically and radiologically in order to decide operability. For the rest of the patients, only right heart catheterization can identify patients with precapillary PH and these patients must be further evaluated (clinically, by blood samples and by imaging techniques) in order to be classified in one the PH groups of the classification. For the future the discovery of novel risk factors and understanding the mechanism involved with the already known ones represent two major points of research.

Rationale and Objectives Today, lung volumes can be easily calculated from chest computed tomography (CT) scans. Modern postprocessing workstations allow automated volume measurement of data sets acquired. However, there are challenges in the use of lung volume as an indicator of pulmonary disease when it is obtained from routine CT. Intra-individual variation and methodologic aspects have to be considered. Our goal was to assess the reliability of volumetric measurements in routine CT lung scans. Materials and Methods Forty adult cancer patients whose lungs were unaffected by the disease underwent routine chest CT scans in 3-month intervals, resulting in a total number of 302 chest CT scans. Lung volume was calculated by automatic volumetry software. On average of 7.2 CT scans were successfully evaluable per patient (range 2–15). Intra-individual changes were assessed. Results In the set of patients investigated, lung volume was approximately normally distributed, with a mean of 5283 cm 3 (standard deviation = 947 cm 3 , skewness = −0.34, and curtosis = 0.16). Between different scans in one and the same patient the median intra-individual standard deviation in lung volume was 853 cm 3 (16% of the mean lung volume). Conclusions Automatic lung segmentation of routine chest CT scans allows a technically stable estimation of lung volume. However, substantial intra-individual variations have to be considered. A median intra-individual deviation of 16% in lung volume between different routine scans was found.

Purpose Findings not associated with thromboembolic disease on routine perfusion lung scan may sometimes have particular clinical significance. We wanted to assess the clinical importance and overall survival after the recognition of a lymphangitic carcinomatosis pattern on perfusion lung scan. Case report We report a case of lymphangitic carcinomatosis pattern on perfusion lung scan performed in a previously healthy patient who had rapid progressive course and died the next day. Method A Medline search of case reports that describes either lymphangitic carcinomatosis or tumour microemboli on perfusion lung scan. Results There were a total of 32 patients identified in 21 articles from various countries, including our case. The studied perfusion pattern was reported more often in female patients (81%) was associated with a progressive history of dyspnea (69%) and normal or mild findings on chest radiograph (58%). Of the 29 patients with available outcome data, 79% (23/29) had a progressive course after the lung scan interpretation. In 18 of these 23 cases, the actual interval of survival was given: 67% of these patients (12/18) died within the first month. Discussion A lymphangitic carcinomatosis perfusion pattern on scintigraphic imaging is associated with a poor prognosis. Nuclear medicine physicians should be aware of this association and that raising the suspicion for a metastatic process may make a difference in the treatment plan of these patients.

Resume La maladie de Gaucher est une maladie lysosomiale non exceptionnelle en Tunisie. Le type 1 est de loin le plus frequent. L’atteinte pulmonaire est consideree comme rare mais souvent grave. Elle peut avoir plusieurs mecanismes puisqu’il peut s’agir d’une atteinte interstitielle secondaire a l’infiltration par les cellules de Gaucher, d’une hypertension arterielle pulmonaire ou des shunts arterio-veineux intrapulmonaire. Nous rapportons une observation d’un syndrome hepatopulmonaire compliquant une maladie de Gaucher type 1 chez un enfant âge de 14 ans. Le diagnostic de la maladie de Gaucher a ete confirme a l’âge de deux ans par le dosage enzymatique de la β-glucosidase intraleucocytaire. L’enfant a presente une dyspnee d’aggravation progressive avec un hippocratisme digital et une cyanose peribuccale. Les gaz du sang arteriel a l’air ambiant ont montre une hypoxemie severe avec une pression arterielle en oxygene (PaO2) a 56,9 mmHg. Le diagnostic du syndrome hepatopulmonaire a ete confirme par la constatation d’un shunt intrapulmonaire a l’echographie cardiaque couplee a l’epreuve aux microbulles et la scintigraphie pulmonaire de perfusion aux macroagregats d’albumine. Le traitement enzymatique substitutif de la maladie de Gaucher etant indisponible pour notre patient, il a ete traite symptomatiquement par une oxygenotherapie a domicile. La severite du syndrome hepatopulmonaire nous incite a pratiquer regulierement un depistage precoce chez les enfants ayant une maladie hepatique chronique.

The expanded use of multi-detector computed tomography has increased the proportion of diagnosed subsegmental pulmonary embolism. The clinical significance and prognosis of these embolisms remain unknown and the benefit of anticoagulation is not yet proven. Several previously validated diagnostic strategies for pulmonary embolism exclusion (based on single-detector computed tomography and ventilation-perfusion lung scan) were unable to detect most of these subsegmental pulmonary embolisms. However, these strategies have been proven safe, with very few thromboembolic events at 3 months. Furthermore, the comparison between studies using single-detector and multi-detector computed tomography suggests increased rates of PE diagnosis and increased rates of anticoagulated patients without improvement of the three-month followup. Subsegmental pulmonary embolisms seem to have less clinical impact than proximal pulmonary embolisms and a better long-term prognosis. In some patients with isolated subsegmental pulmonary embolism, the bleeding risk related to anticoagulation might outweigh the benefit of preventing recurrent thromboembolic event.

Fundamento y objetivo Analizar las tendencias de utilizacion de gammagrafia de ventilacion-perfusion (gammaV/Q), tomografia computarizada helicoidal (TCH) y arteriografia pulmonar para el diagnostico de embolia pulmonar (EP) en Espana, considerando los datos del Sistema Nacional de Salud (SNS) y el Registro RIETE y examinar las analogias diagnosticas de la gammaV/Q y la TCH en RIETE, con especial referencia a la gammaV/Q de probabilidad intermedia/indeterminada (GV/QPI). Material y metodo Se examinaron las tendencias anuales en pruebas de imagen para diagnosticar EP en 5.678 pacientes espanoles incluidos en el Registro RIETE (2001 a 2005) y se compararon con los pertenecientes al SNS (periodo 1999-2003). En el RIETE se compararon los resultados analogos entre los casos con gammaV/Q y TCH concomitantes y arteriografia y gammaV/Q o TCH. Resultados Hubo una tendencia creciente en la utilizacion de TCH, que supero en 2002 (RIETE) y en 2003 (SNS) a la gammaV/Q. En 732 casos con ambas pruebas, se obtuvieron resultados analogos en el 53%. En 116 casos con gammaV/QPI, la TCH disponible fue positiva a EP en un 87%. Cuando ademas habia signos clinicos de EP, la TCH fue positiva en un 95%. En 29 casos con angiografia pulmonar (AP) y TCH, los resultados fueron analogos en un 83% y en 31 casos con arteriografia y gammaV/Q, en un 77%. Conclusiones Actualmente, en Espana, la TCH es el metodo mas utilizado para el diagnostico de EP, aunque siguen realizandose numerosos estudios con gammaV/Q. En los resultados de gammaV/QPI es aconsejable estudiar la posible trombosis venosa profunda y, si la hay, los resultados del RIETE permiten asegurar la coexistencia de EP en un 87-95% de casos.

Study objective To study whether there is any difference in thfe clinical characteristics between the two patterns of perfusion lung scan of idiopathic pulmonary arterial hypertension (normal vs. diffuse, multiple ill-defined defects) and whether the perfusion lung scan patterns of these patients would predict the effect of long-term use of beraprost sodium. Methods We evaluated 27 patients who used beraprost sodium for over 3 months, and noted a diffuse patchy pattern in 13 cases and a normal pattern in the remaining 14 cases. We judged that beraprost sodium was effective when at least two of the following conditions were met: improvement in symptom of dyspnea, more than 10% decrease in peak velocity of tricuspid valve regurgitation by echocardiography ( V max ), or more than 10% increase in 6-min walking distance. Results At baseline there was no difference between the two groups in dyspnea, hemodynamic parameters, and 6-min walking distance. After the use of beraprost sodium, the normal group showed improvement in dyspnea, 6-min walking distance, and V max . But the diffuse patchy group showed no improvement. The use of beraprost sodium in the normal group was effective in 10 out of 14 cases, but was effective in only two out of 13 cases in the diffuse patchy group. Conclusion Perfusion lung scan pattern in patients with idiopathic pulmonary arterial hypertension is a useful prognostic indicator of the response to beraprost sodium.

Pulmonary embolism is an affection that remains often unrecognized despite diagnostic and therapeutic advances in this field; it yields high rates of lethality and morbidity. The classical diagnostic approach based on pulmonary angiography tends to be replaced by more pragmatic non-invasive investigations. Perfusion-ventilation lung scan has an excellent sensitivity, but is limited by the large number of inconclusive results. Helical CT scanning, Elisa-based D-dimer measurement, lower-limb venous Doppler ultrasonography and echocardiography are used today as parts of non-invasive diagnostic strategies. Low-molecular-weight heparins proved to be more effective than unfractionated heparin in the treatment of deep-vein thrombosis. Their results are interesting in the treatment of pulmonary embolism. Oral anticoagulant therapy is introduced early in order to limit the risk for heparin associated thrombocytopenia. Its duration depends essentially on the recurrent character of the thromboembolic disease and on the possible existence of an underlying thrombophilia.

The thorough detection of nodules in high-resolution CT lung scans is an increasingly difficult, labor-intensive, and critical radiological task. Recent clinical research on early lung cancer CT presentation has demonstrated the significant clinical need to detect the more subtle subsolid nodules as well as the traditional solid nodule. We have developed a model-based computer-aided detection (CAD) algorithm designed to automatically detect both of these nodule presentation types through the use of precise mathematical models that capture scanner physics and anatomy and pathology domain knowledge. Our model-based CAD algorithm utilizes a Bayesian framework for determining the probability of multiple competing anatomical and pathological events throughout the lung. Using this model-based CAD algorithm on 50 low-dose CT lung cancer screening cases, we measured a 3.9% average improvement in radiologist sensitivity (93.8% to 97.7%) with 8.3 false positives per case for all nodules ≥5 mm in size. This model-based approach can be easily extended to support additional anatomy and pathology models as clinical understanding and scanning practices improve.

Study Objective: Emergency physicians frequently rely on normal findings from a lower extremity venous ultrasound examination as a method to decrease the probability of pulmonary embolism (PE) in outpatients with a nondiagnostic ventilation-perfusion lung scan (V/Q scan). The objective of this study was to evaluate the diagnostic utility of bilateral lower extremity venous ultrasound scanning in the diagnosis of PE in emergency department patients with a low-, moderate-, or indeterminate-probability (nondiagnostic) V/Q scan. Methods: This prospective, 2-center, descriptive study was conducted at the EDs of 2 large teaching hospitals. From an initial cohort of 570 nonreferred outpatients, a convenience sample of 156 patients who had both a nondiagnostic V/Q scan and a lower extremity venous ultrasound scan performed was selected as the study population. The sensitivity and specificity for a single lower extremity venous ultrasound scan and the posttest probability of PE were determined for the study population. Results: In the study population, the best-case sensitivity of the lower extremity venous ultrasound scan for PE was 54% (95% confidence interval [CI] 37% to 71%) and the specificity was 98% (95% CI 94% to 100%). The likelihood ratio of a positive test result was 27. The likelihood ratio of a negative test result was 0.49, yielding a lowest possible posttest probability of PE of 12% (95% CI 6% to 17%). Conclusion: This study demonstrates that the combination of a nondiagnostic (low, moderate, or indeterminate) V/Q scan plus a single negative result from lower extremity venous ultrasound examination, even in a best-case scenario, does not exclude the diagnosis of PE. [Daniel KR, Jackson RE, Kline JA. Utility of lower extremity venous ultrasound scanning in the diagnosis and exclusion of pulmonary embolism in outpatients. Ann Emerg Med. June 2000;35:547-554.]

Objective To assess clinicians' agreement on how they interpret lung scan reports with regard to the diagnosis of pulmonary embolism. Design In this prospective study, nuclear medicine physicians provided two types of reports for each lung scan: a routine descriptive report and a short form with a standardized conclusion on the likelihood of pulmonary embolism: “high probability,” “no conclusion,” and “diagnosis excluded.” Three independent blinded senior clinicians reviewed all routine reports and chose one of the following conclusions: “high probability,” “no conclusion,” or “diagnosis excluded.” Setting An acute care teaching hospital near Paris. Subjects Eighty-two lung scans were studied. Main outcome measurements Inter-clinician agreement and agreement between clinicians' conclusions and the nuclear medicine physicians' standardized reports were analyzed using the kappa index. Results The distribution of the clinicians' conclusions from routine reports strongly differed (p Conclusion Reading the same routine reports, clinicians reached different conclusions. Furthermore these differed greatly from the nuclear medicine physicians' standardized conclusions. These results support the notion that physicians should be given standardized reports.

In contrast to lower extremity deep venous thrombosis (LEDVT), it is widely believed that upper extremity deep venous thrombosis (UEDVT) is associated with minimal morbidity or mortality.In an attempt to compare the two disease processes with respect to pulmonary embolism and mortality, we have reviewed records and performed interviews of 430 patients with LEDVT and 52 patients with UEDVT presenting to our institution between January 1994 and June 1995.Pulmonary embolism was documented by ventilation/perfusion lung scan in 9 of 52 patients (17%) with UEDVT and 33 of 430 patients (8%) with LEDVT (P0.05). Twenty-five of the UEDVT patients (48%) died within 6 months of the diagnosis of UEDVT. Conversely, 14 patients (13%) in the LEDVT group died within 6 months of the diagnosis of LEDVT (P0.0002).Contrary to previous reports, this study suggests that UEDVT is associated with a higher morbidity and mortality as compared with LEDVT. These data show that UEDVT has been an underrecognized predictor of morbidity and mortality.

Rationale and Objectives. The authors have developed an automated computerized technique for registering radionuclide lung scan images with digital chest radiographs. Methods. Threshold analysis was used to construct contours around the high-activity regions of radionuclide ventilation-perfusion images. Analogous contours were constructed around the lung regions of the corresponding digitized radiographs. Contour dimensions and anatomic landmark locations were then used to superimpose the radiographic, ventilation, and perfusion images. Results. Evaluation of 25 sets of images indicated that the scheme provided adequate to excellent registration in 91% of the pairwise combinations. Conclusion. This automated scheme for registering ventilation-perfusion images with digital chest radiographs has the potential to aid radiologists in the interpretation of these images.

Aim of this study was to evaluate rapid D-Dimer tests for their utility in diagnosis of acute pulmonary embolism (PE). Tests were performed in 183 consecutive pats referred for lung scanning because of clinically suspected PE. According to lung scans and the clinical course of disease 19 pats were classified to have PE with high probability and 164 with low probability. An ELISA (Agen) was used as the D-Dimer reference, and results compared with those of a turbidimetric (Behring), an immunofiltration (Nycomed), latex plasma and whole blood agglutination test (both Agen). There was a poor correlation between the turbidimetric test and either the ELISA (R = 0.38) and immunofiltration test (R = 0.49). The correlation between the ELISA and immunofiltration test was better (R = 0.73). The qualitative latex and whole blood agglutination tests were better fitted to ELISA since positive and negative samples were overlapped only in their 1st and 9th percentiles of ELISA values. The whole blood agglutination test was positive at lower ELISA values than the latex test. The highest sensitivity test for PE was the immunofiltration test (95%) (500ng/mL cut-off), followed by the turbidimetric method (89%) (66ng/mL), the ELISA (89%) (300ng/mL), the whole blood test (88%) and the latex test (68%). Specificity was lowest for the immunofiltration test (33%), intermediate (57-65%) for the turbidimetric and whole blood agglutination tests, and highest for the ELISA and the most insensitive latex test (76/77%). The whole blood assay was found to be the fastest and most suitable for bed site testing but weak positives were difficult to read. The immunofiltration test required plasma preparation but allowed objective semiquantitation of results. The less rapid turbidimetric assay was fully quantitative and objective.

Purpose The purpose of this investigation was to evaluate the diagnostic accuracy of radionuclide scintigraphic lung scans and clinical assessment in critically ill patients with suspected acute pulmonary embolism. Materials and methods Critically ill patients were defined as follows: (1) patients who were hypoxemic on room air, and not given ventilatory support (n=89); (2) patients given ventilatory support (n=46); and (3) patients in ICUs, but not given ventilatory support (n=85), and hypotensive patients who were not hypoxemic or given ventilatory support (n=3). Comparisons were made with patients who had none of these characteristics of critically ill patients (n=627). Data are from the Prospective Investigation of Pulmonary Embolism Diagnosis. Results The sensitivities, specificities, and positive predictive values of high probability lung scans among each of the four categories of critically ill patients were not statistically significantly lower than values in noncritically ill patients. The positive predictive values of the clinical assessments did not differ to a statistically significant extent from noncritically ill patients. Clinical assessment, when concordant with the lung scan interpretation, usually increased the positive predictive value for pulmonary embolism. Conclusion Scintigraphic lung scans and clinical assessment retain their diagnostic value, even in critically ill patients.

Little is known about the clinical implications of residual pulmonary vascular obstruction(RPVO) on long-term outcomes and about the optimal timing of V-Q scan control during patient follow-up. We aimed to investigate the prognostic value on 5-year adverse events of RPVO, measured by two ventilation

Summary Ventilation-perfusion scintigraphy remains an important diagnostic tool in the evaluation of patients suspected of having PE. It is important for the emergency physician to be able to use the information from a lung scan appropriately in the diagnostic management of this elusive and life-threatening disorder. This requires a clear knowledge of how these scans are interpreted as well as a consultative approach between the physician ordering the lung scan and the nuclear medicine physician interpreting it. Each can ultimately contribute to the development of an effective management plan. It is important for the clinician to understand that a low-probability lung scan does not rule out PE, but in fact can have up to a 40% probability of PE when clinical suspicion is high.

Previously, we reported that the sensitivity of plasma DNA for patients with pulmonary emboli was 83 to 88 percent. To confirm these findings in a more comprehensive study, we collected plasma samples from 137 consecutive patients undergoing 148 ventilation-perfusion lung scans for pulmonary embolism. DNA was measured using a counter-immunoelectrophoresis technique that used high titer precipitating double-stranded DNA antibody from a patient with systemic lupus erythematosus. In addition to 17 patients (17 lung scans) excluded for not having plasma collected, 32 patients (37 lung scans) were excluded for having either a condition other than pulmonary embolism that could be associated with plasma DNA or for having nonacute symptoms. Eighteen of 22 patients with a diagnosis of pulmonary embolism (defined by either a high probability lung scan or abnormal pulmonary angiogram) had detectable plasma DNA. Only four of 27 patients without pulmonary embolism (defined by either a normal lung scan or normal pulmonary angiogram) had plasma DNA detected. Based on these results, plasma DNA had a sensitivity of 82 percent and a specificity of 85 percent for this condition. Plasma DNA is a promising test for pulmonary embolism and could help physicians interpret equivocal lung scan findings and thereby clarify difficult decisions such as the need for pulmonary angiography. (Chest 1990; 97:63-68)

The value of ventilation/perfusion (V/Q) lung scans in the diagnosis of acute pulmonary embolism (PE) was described in the results of the collaborative study of the Prospective Investigation of Pulmonary Embolism Diagnosis (PIOPED). 1 The effects of preexisting cardiac or pulmonary disease and of a normal chest radiograph on the diagnostic value of V/Q scans 2,3 were also described among patients in PIOPED. The present report assesses the value of V/Q scans compared with that of perfusion scans alone in the diagnosis of acute PE.

A 53-year old white man underwent a left pneumonectomy for alveolar cell carcinoma. His postoperative course was complicated by pneumonia. At a follow-up clinic visit, the patient complained of a “roaring sound” during respiration. A follow-up PFT did not show the expected loss of volume (nitrogen washout) from a preoperative PFT, suggesting a bronchopleural fistula. A chest x-ray film and xenon lung scan confirmed the diagnosis. The fistula was surgically repaired. (Chest 1991; 100:582-84)

A V ˙ / Q ˙ lung scan was obtained in a patient with LLL collapse who was receiving IPPV and PEEP. This revealed absent ventilation and hyperperfusion to the collapsed lobe. After a reduction in PEEP from 12 to 5 cm H 2 O, a repeat V ˙ / Q ˙ scan showed a more even distribution of pulmonary perfusion. Arterial hypoxemia improved.

A 71-year-old man presented with herpes zoster ophthalmicus and ocular involvement. Following the institution of intravenous therapy with acyclovir, the patient developed fever, hemoptysis, and a pleural friction rub. A ventilation-perfusion lung scan showed no defects; roentgenograms showed bilateral infiltrates and a left-sided pleural effusion. The fever abated promptly following discontinuation of acyclovir, and radiographic abnormalities resolved over ten days. No other anti-infective therapy was given. To our knowledge, the syndrome of fever, pulmonary infiltrates, and pleural effusion following use of acyclovir has not been previously reported.

PURPOSE: To compare the diagnostic performance of an artificial neural network (ANN) with that of physicians in patients with suspected pulmonary embolism (PE). MATERIALS AND METHODS: An ANN was developed to predict PE by using findings from ventilation-perfusion lung scans and chest radiographs. First, the network was evaluated on 1,064 cases from the Prospective Investigation of Pulmonary Embolism Diagnosis (PIOPED) study that had a definitive angiographic outcome. An upper and lower bound of its diagnostic performance was provided depending on case difficulty. Then, the network was tested on 104 patients with suspected PE in whom pulmonary angiography was essential for diagnosis. The diagnostic performance of the ANN was compared with that of (a) two nuclear medicine physicians who read the scans for the needs of this study and (b) the nuclear medicine physicians who originally read the scans. The effects of case and observer selection on performance were addressed. RESULTS: The ANN outperformed the ph...

Twenty-five consecutive patients with obliterative pulmonary hypertension were studied. Primary pulmonary hypertension (17 patients) or chronic thromboembolic pulmonary hypertension (eight patients) was diagnosed by pulmonary angiography or autopsy. Clinical symptoms, physical findings, chest roentgenograms, electrocardiograms, and pulmonary function studies did not differentiate the patients with primary pulmonary hypertension (PPH) from those with chronic thromboembolic pulmonary hypertension (TPH). All eight patients with TPH had a lung scan interpreted as high probability for pulmonary emboli while all 17 patients with PPH had a lung scan interpreted as normal or low probability for emboli. While there was close clinical similarity between patients with PPH and TPH, the presence of a normal or low probability lung scan excluded the diagnosis of TPH.

N PREVIOUS REPORTS, 1'2 brief comments were made on the comparison of pulmonary angiography and lung scan in the assessment of thrombolytic therapy in patients with pulmonary embolism. Much information concerning the sensitivity and specificity of these two methods in the detection and follow-up study of pulmonary embolism w~s left out because of the length of these reports and consideration of priority. In this communication, we shall deal with a detailed comparison of pulmonary angiography and lung scan. We believe the information derived from this trial is valuable in the critical examination of the two methods and is not readily available elsewhere for the following reasons: (1) both pulmonary angiography and lung scan were performed in the same patients under standardized techniques usually within 6 hr of each other, (2) these data were from multiple institutions, (3) interpretations were performed by independent panelists consisting of vascular radiologists for the pulmonary angiograms and specialists in nuclear medicine for

The clinical courses of three children are described. They were initially thought to have troublesome asthma alone or in association with other diseases. The children had radioactive gas lung scans using 13N for studies of ventilation and perfusion which in each case revealed one entirely healthy lung and one disordered lung. The technique of 13N gamma scanning is described and its clinical value in such patients is discussed.

Difficulties persist in the accurate clinical diagnosis of major pulmonary embolism despite the availability of lung scans and pulmonary angiography. To evaluate factors associated with the correct antemortem diagnosis of pulmonary embolism, we reviewed all 1,455 autopsy reports at the Peter Bent Brigham Hospital from 1973 to 1977. Of 54 patients identified with anatomically major pulmonary embolism at autopsy, 16 (30 percent) had correct antemortem diagnosis. Accuracy was far greater in postoperative patients (64 percent) (p = 0.02) and in patients with autopsy-proved venous thrombosis (55 percent) (p = 0.005). Lung scanning (82 percent) (p = 0.0002) and pulmonary angiography (80 percent) (p = 0.05) during the 10 days prior to death were also associated with an increased tendency to correct clinical diagnosis of pulmonary embolism. In contrast, among 21 patients with autopsy-proved major pulmonary embolism who also had pneumonia, no pulmonary embolism was diagnosed before death (p = 0.0001). Furthermore, among patients 70 years of age or older, only 10 percent with pulmonary embolism at postmortem examination had a correct diagnosis prior to death (p = 0.02). In patients with pneumonia or in elderly patients, an increased awareness of the possibility of pulmonary embolism and more frequent use of lung scanning and pulmonary angiography may increase the accurate clinical diagnosis of pulmonary embolism.

The postpneumonectomy FEV1 was predicted in 24 patients with severe chronic obstructive pulmonary disease (FEV1 less than or equal to 2.0 L) and a lung mass using the quantitative lung scan (QLS) and lateral position test (LPT). Although a good correlation (r = .72, p = 0.0006) was found between the FEV1 predicted by QLS and LPT, there was more than 10 percent difference between the result in 59 percent of the subjects. A subgroup of these patients performed multiple (two to five) LPTs, and the results were calculated blindly to assess variability. The variation seen was 14 times greater than in previously reported normal subjects. Calculations suggest that as many as 37 tracings would be needed on each patient to obtain an acceptably low measurement error. Whereas there was a good overall correlation between the predicted postpneumonectomy FEV1 using both methods, the variability found with LPT would suggest extreme caution in its use.

Fifty-eight patients, 38 of whom had pulmonary emboli, were evaluated for pulmonary occlusive disease with flow-directed balloon occlusion pulmonary cineangiography. Areas studied were selected by radionuclide perfusion lung scans and indeterminant areas of pulmonary occlusion were imaged on standard catheter pulmonary magnification cut films. In 4 of 38 patients, the balloon occlusion technique demonstrated peripheral pulmonary emboli not seen on standard pulmonary arteriography. Selective flow-directed balloon occlusion pulmonary cineangiography is an effective adjunct for evaluating some patients with pulmonary emboli.

Two cases of pulmonary hypoperfusion occurring after mediastinoscopic examination were demonstrated on lung scans. In one case, this finding on the ninth day required a pulmonary angiographic study that yielded normal findings. Repeat lung scans were normal. We propose that localized mediastinal edema or bleeding after mediastinoscopic examination can produce defects of hypoperfusion, and we urge caution in the interpretation of lung scans up to nine days after mediastinoscopic examination.

The records of 158 patients who underwent pulmonary angiography for the presumed diagnosis of acute pulmonary embolism were retrospectively reviewed. Of the 111 patients in the category of high probability for pulmonary embolism based on clinical impression, 60 patients (54 per cent) had a positive pulmonary angiogram. Of the forty-seven patients in the low probability group, ten (21 per cent) had a positive angiogram. Forty-eight of the seventy-three patients (66 per cent) with a high probability lung scan had a positive pulmonary angiogram. Eleven of twelve patients (92 per cent) with a high probability ventilation-perfusion scan had a positive pulmonary angiogram, and two of eight patients (25 per cent) with a low probability ventilation-perfusion scan had a positive pulmonary angiogram. The mean PO2 of patients with a positive pulmonary angiogram was 64 mm Hg, and the mean PCO2 30 mm Hg. The mean PO2 of patients with a negative pulmonary angiogram was 63 mm Hg and the mean PCO2 34 mm Hg. Based on these data, we believe that the accuracy of pulmonary angiography in diagnosing acute pulmonary embolism is much higher than that of the clinical impression, arterial blood gas determinations, and lung scanning technics.

A patient with bronchiolo-alveolar cell carcinoma presented with a veno-arterial shunt localized to the area of tumor involvement by differential position shunt testing. Perfusion lung scan revealed increased radionucleotide uptake in the area of the tumor, confirmed by pulmonary angiography, and suggested that the primary blood supply to the tumor was originating from the pulmonary circulation. Surgical resection of the tumor resulted in marked reduction of the intrapulmonary shunt.

SUMMARY A broad spectrum of lung disease occurs in association with HIV infection. Included are both infectious and neoplastic processes and idiopathic disorders. To insure prompt, accurate, and efficient diagnosis, a logical, staged sequence of tests should be applied. Chest films and, in some instances, pulmonary function tests and gallium-67 citrate lung scans serve to provide objective indications of lung disease. Each of these tests is sensitive but nonspecific. Specific infecting organisms, particularly P. carinn, can be identified by examining sputum induced by inhalation of 3 per cent saline. Bronchoscopic procedures, including BAL and TBB, are highly sensitive and should be performed in patients having non-diagnostic sputum examinations. Tests involving antigen and antibody detection are of little use in the evaluation of individual patients. Detection of recurrent episodes of PCP is difficult because abnormalities in the usual screening tests may be residual from previous episodes. Finding P. carinii in sputum or bronchoscopic specimens soon (within 2 to 3 months) after a confirmed episode of PCP likely represents residual organisms rather than recrudescence of the infection. Empiric diagnosis of P. carinii should be employed only in limited circumstances when specific diagnostic studies are not available, are contraindicated, or are refused.

We evaluated 33 high-risk patients before pneumonectomy, all of whom had a forced expiratory volume in one second (FEV1) of less than 2.0 L before surgery. A quantitative perfusion lung scan was used to assess the right-left distribution of blood flow. A predicted postoperative FEV1 was calculated from the information on the lung scan and the preoperative FEV1. If this calculated value exceeded 800 ml, the patient was physiologically cleared for surgery up to and including a pneumonectomy. Surgery was otherwise believed to be contraindicated in the absence of studies using balloon occlusion. Perioperative mortality (less than or equal to 30 days after surgery) was found to be 15 percent (5/33). In surgery of this magnitude, we find this to be an acceptable percentage of mortality and have continued to use these simple physiologic criteria to determine whether a patient can tolerate pneumonectomy.

The relationship between size of the perfusion defect as seen by perfusion lung scan (PLS) and size of the mass lesion as seen radiologically was correlated with the presence of regional adenopathy in 100 consecutive patients with bronchogenic carcinoma. All patients underwent scanning before open thoracotomy or mediastinotomy and had histologic documentation of the disease. Each perfusion lung scan was classified as follows: (1) perfusion defect larger than the mass lesion, (2) perfusion defect of the same size as the mass lesion, or (3) no focal defect seen. Among patients with a larger perfusion defect 84 per cent were found to have regional lymph node involvement, whereas among patients in whom a larger defect was not present only 23 per cent had such extension of the disease.

Guidelines that are frequently used to select patients with suspected pulmonary embolus for pulmonary angiography evolved from studies conducted 10 to 15 years ago. To determine If clinical practice in a referral medical center should continue to be based on these guidelines, clinical and angiographic data on 106 patients recently studied were compared with similar data obtained from the same institution in the previous era. The need to perform angiography if a lung scan demonstrated low or high probability for embolus was also examined, along with clinical, laboratory, and hemodynamic findings previously reported to be of diagnostic utility. There has been a marked change in the spectrum of patients studied. Cancer patients and patients who have undergone abdominal and pelvic surgery comprise the preponderance of patients undergoing angiography. Lung scans had a clinically important error rate in that more than one third of these selected patients with either a high- or low-probability scan had discordant results on angiography. Clinical criteria for selecting patients for pulmonary angiography should reflect the contemporary spectrum of patients with pulmonary embolus, as well as the limitations of clinical judgment and of the lung scan.