Acute pulmonary embolism detection with ventilation/perfusion SPECT combined with full dose CT: what is the best option? / SPECT/TC de ventilación-perfusión pulmonar en el diagnóstico del tromboembolismo pulmonar agudo

Aim. To compare diagnostic accuracy of Ventilation/Perfusion (V/P) single-photon emission computed tomography (SPECT) combined with simultaneous full-dose CT with a hybrid SPECT/CT scanner versus planar ventilation/perfusion (V/P) SPECT and CT angiography (CTA) in patients suspected with acute pulmonary embolism (PE). Methods. Between 2009 and 2011, consecutive patients suspected of acute PE were referred for V/P SPECT/CT (reviewed board approved study). A contrast agent was administered to patients who had no contraindications. Non-contrast V/P SPECT/CT was performed on the remaining patients. All patients were followed-up for at least 3 months. Results. A total of 314 patients were available during the study period, with the diagnosis of PE confirmed in 70 (22.29%) of them. The overall population sensitivity and specificity was 90.91% and 92.44%, respectively for V/P SPECT, 80% and 99.15%, respectively, for CTA, and 95.52% and 97.08% for V/P SPECT/CT. SPECT/CT performed better than V/P SPECT (AUC differences=0.0419, P=0.0043, 95% CI; 0.0131-0.0706) and CTA (AUC differences=0.0681, P=0.0208, 95% CI; 0.0103-0.1259)). Comparing imaging modalities when contrast agent could be administered, sensitivity and specificity increased and V/P SPECT/CT was significantly better than CTA (AUC differences=0.0681, P=0.0208, 95% CI; 0.0103-0.1259) and V/P SPECT (AUC differences=0.0659, P=0.0052, 95% CI; 0.0197-0.1121). In case of non-contrast enhancement, there was non-significant increase of specificity. Secondary findings on CT impacted patient management in 14.65% of cases. Conclusion. Our study shows that combined V/P SPECT/CT scanning has a higher diagnostic accuracy for detecting acute PE than V/P SPECT and CTA alone. When feasible, V/P SPECT/CT with contrast enhancement is the best option (AU)

Objetivo del estudio. Valorar la exactitud diagnóstica de la SPECT/TC de ventilación-perfusión (V/P) pulmonar de alta dosis mediante un equipo híbrido SPECT/TC frente a la SPECT de V/P pulmonar y a la angiografía por TC (CTA) en pacientes con sospecha de tromboembolismo pulmonar (TEP) agudo. Metodología. Entre 2009 y 2011, se estudiaron de forma consecutiva con SPECT/TC de V/P pulmonar los pacientes con sospecha de TEP agudo que acudieron a nuestro centro (estudio aprobado por el comité de ética hospitalaria). A los pacientes que no presentaban contraindicaciones se les administró contraste yodado (CI) por vía intravenosa. En el resto se realizó un estudio SPECT/TC de V/P pulmonar sin CI. Los pacientes fueron seguidos durante un período de 3 meses. Resultados. Se estudiaron un total de 314 pacientes. En 70 (22,29%) se confirmó el diagnóstico de TEP. La sensibilidad y especificidad para la población global fue: 90,91 y 92,44% respectivamente para la SPECT de V/P; 80 y 99.15% para la CTA; y 95.52 y 97.08% para la SPECT/TC de V/P pulmonar. La SPECT/TC presentaba una exactitud diagnóstica superior a la SPECT de V/P (diferencias AUC=0,0419; p=0,0043; IC95%: 0,0131-0,0706) y la CTA (diferencias AUC=0,0681, p=0,0208; IC95%: 0,0131-0,1259). Comparando las diferentes modalidades cuando se administró CI, observamos un aumento de la sensibilidad y la especificidad de la SPECT/TC de V/P superior a la CTA (diferencias AUC=0,0681; p=0,0208; IC95%: 0,0131-0,1259) y a la SPECT de V/P (diferencias AUC=0,0659; p=0,0052; IC95%: 0,0197-0,1121). En el caso de no administrar CI se observó un aumento no estadísticamente significativo de la especificidad. Los hallazgos secundarios de la TC provocaron un cambio en el manejo del paciente en un 14,65% de los casos. Conclusión. Nuestro estudio demuestra que el estudio combinado SPECT/TC de V/P pulmonar tiene una mayor exactitud diagnóstica para detectar el TEP agudo que la SPECT de V/P pulmonar o la CTA por sí solos. Cuando es factible, la SPECT/TC de V/P pulmonar con CI es la mejor opción diagnóstica (AU)

Ventilation/Perfusion SPECT lung scintigraphy and computed tomography pulmonary angiography in patients with clinical suspicion of pulmonary embolism / Gammagrafía pulmonar SPECT de Ventilación/Perfusión y angiografía pulmonar computerizada en pacientes con sospecha clínica de tromboembolismo pulmonar

The aim was to compare ventilation/perfusion SPECT lung scintigraphy (V/Q-SPECT) and computed tomography pulmonary angiography (CTPA) in patients with suspicion of pulmonary embolism (PE). Material and methods. This prospectively designed study included 53 patients with intermediate or high clinical probability of PE. A V/Q-SPECT and CTPA was performed on all patients. The V/Q-SPECT was interpreted according to the European Association of Nuclear Medicine and Molecular Imaging (EANMMI) guidelines. CTPA was reported as positive, negative, or indeterminate. Results. CTPA was positive in 22 cases, negative in 28, and indeterminate in 3. V/Q-SPECT was positive in 27 cases, negative in 24, and non-diagnostic in 2. In the 22 with positive CTPA, V/Q-SPECT was positive in 18, negative in 3, and non-diagnostic in 1. In the 28 with negative CTPA, V/Q-SPECT was positive in 8, negative in 19, and non-diagnostic in 1. In the 3 with indeterminate CTPA, V/Q-SPECT was positive in 1 and negative in 2. In the 2 non-diagnostic cases V/Q-SPECT, CTPA was positive in 1 and negative in one. In the 10 high clinical probabilities, CTPA and V/Q-SPECT were positive in 7, negative in 2, and in 1, CTPA was positive and V/Q-SPECT negative. In the 38 intermediate probability group, CTPA and V/Q-SPECT were positive in 11, negative in 17, with CTPA negative and V/Q-SPECT positive in 8, and in 2 CTPA was positive and V/Q-SPECT negative. The results show that V/Q-SPECT detected PE in 5 patients more than CTPA. Conclusion. Our results show a 77% concordance of both techniques. Overall V/Q-SPECT detected PE in 18% more patients than CTPA in the intermediate group. Both techniques have a complementary role when a diagnosis cannot be made with one of them (AU)

Objetivo. Comparar la gammagrafía pulmonar SPECT de ventilación/perfusión (SPECT-V/Q) y la angiografía pulmonar computarizada (CTPA) en pacientes con sospecha de tromboembolismo pulmonar (TEP). Material y métodos. Estudio prospectivo en 53 pacientes con probabilidad intermedia y alta de TEP. A todos se les realizó SPECT-V/Q y CTPA. La SPECT-V/Q fue interpretada según la guía publicada por la European Association of Nuclear Medicine and Molecular Imaging (EANMMI). La CTPA fue reportada como positiva, negativa o indeterminada. Resultados. La CTPA fue positiva en 22, negativa en 28 e indeterminada en 3. La SPECT-V/Q fue positiva en 27, negativa en 24 y no diagnóstica en 2. En 22 con CTPA positiva, la SPECT-V/Q fue positiva en 18, negativa en 3 y no diagnóstica en una. En 28 con CTPA negativa, la SPECT-V/Q fue positiva en 8, negativa en 19 y no diagnóstica en uno. En 3 con CTPA indeterminada, la SPECT-V/Q fue positiva en una y negativa en 2. En 2 con SPECT-V/Q no diagnóstica, la CTPA fue positiva en una y negativa en una. En 10 con probabilidad clínica alta la CTPA y la SPECT-V/Q fueron positivas en 7, negativas en 2 y en una la CTPA fue positiva y la SPECT-V/Q negativa. En 38 con probabilidad intermedia la CTPA y la SPECT-V/Q fueron positivas en 11 y negativas en 17. En 8 la CTPA fue negativa y la SPECT-V/Q positiva, en 2 la CTPA fue positiva y la SPECT-V/Q negativa; por lo tanto, la SPECT-V/Q detectó TEP en 5 pacientes más de la CTPA. Conclusión. Nuestros resultados muestran un 77% de concordancia entre ambas técnicas. En general la SPECT-V/Q detectó TEP en 18% más pacientes que la CTPA en el grupo con probabilidad intermedia. Ambas técnicas tienen un papel complementario cuando el diagnóstico no puede ser alcanzado por una de ellas (AU)

Significado pronóstico de la trombosis venosa profunda asintomática en pacientes con tromboembolia de pulmón aguda sintomática / Prognostic significance of asymptomatic deep vein thrombosis in patients presenting with acute symptomatic pulmonary embolism

OBJETIVO: Evaluar el significado pronóstico de la trombosis venosa profunda (TVP) concomitante asintomática en pacientes diagnosticados de tromboembolia de pulmón (TEP) aguda sintomática. MÉTODOS: Se realizó un análisis retrospectivo de una cohorte de 820 pacientes normotensos diagnosticados de TEP aguda sintomática incluidos en el estudio PROTECT. Se les realizó una ecografía de compresión de miembros inferiores. La variable primaria de resultado fue la mortalidad por todas las causas durante los primeros 30 días de seguimiento. La variable secundaria fue la mortalidad por TEP durante el mismo período de tiempo. RESULTADOS: De los 820 pacientes incluidos, un 46% (375) presentaron TVP. El 51% de ellos (193/375) no presentaban sintomatología sugestiva de TVP. Durante el primer mes de seguimiento fallecieron 37 pacientes (4,5%; IC 95%: 3,1-5,4%). Once pacientes de 820 fallecieron por TEP (1,3%; IC 95%: 0,6-2,1%), y 26 (26 de 820 pacientes; 3,2%; IC 95%: 2,0-4,4%) por otras causas (cáncer: 10; insuficiencia cardiaca: 4; insuficiencia respiratoria: 3; sangrado: 3, y otras causas: 6). Los pacientes con TVP asintomática presentaron un riesgo aumentado de muerte por todas las causas (odds ratio [OR] 2,77; IC 95%: 1,35-5,67; p = 0,005) y de muerte por TEP (OR 7,11; IC 95%: 1,42-35,53; p = 0,02). Ninguna de las variables analizadas modificó la asociación entre la TVP asintomática y los eventos considerados. CONCLUSIONES: En pacientes normotensos con TEP aguda sintomática, la TVP asintomática concomitante se asocia a un riesgo aumentado de muerte por todas las causas y por TEP durante el mes posterior al diagnóstico

OBJECTIVE: To evaluate the prognostic significance of concomitant asymptomatic deep vein thrombosis (DVT) in patients with symptomatic acute pulmonary embolism (PE). METHODS: A prospective study was conducted on 820 normotensive patients with PE enrolled in the PROTECT multicentre study. Ultrasound was performed on patients with bilateral lower extremity venous compression to assess for concomitant DVT. The primary study outcome, all-cause mortality, and the secondary outcome of PE-specific mortality, were assessed during the first month of follow-up after PE diagnosis. RESULTS: Of the 820 patients diagnosed with PE, 46% (375/820) had concomitant DVT, and signs or symptoms of DVT were absent in 51% (193 of 375) of these patients. Overall, 37 out of 820 patients died (4,5%; 95% confidence interval [CI], 3,1%-5,9%). Of the 820 patients, 11 (1,3%; 95% CI, 0,6%-2,1%) died from PE, and 26 (3,2%; 95% CI, 2,0%-4,4%) died from other causes (cancer: 10; congestive heart failure: 4; respiratory failure: 3; major bleeding: 3; miscellaneous diseases: 6). Patients with concomitant asymptomatic DVT had an increased all-cause mortality (odds ratio [OR] 2,77; 95% CI, 1,35-5,67;P = .005) and PE-specific mortality (OR 7,11; 95% CI, 1,42-35,53; P = ,02). None of the variables analysed affected the association between DVT and the events studied. CONCLUSIONS: In stable patients with an episode of acute symptomatic PE, the presence of concomitant asymptomatic DVT is an independent predictor of death in the ensuing month after diagnosis

Cuantificación de la circulación pulmonar y sistémica: Qp/Qs. Qué es, cómo se calcula y para qué sirve. Lo que el radiólogo debe saber / What radiologists need to know about the pulmonary-systemic flow ratio (Qp/Qs): what it is, how to calculate it, and what it is for

La resonancia magnética cardiaca aporta abundante información morfológica y funcional al estudio de las cardiopatías congénitas. Entre los datos funcionales se encuentran el gasto pulmonar y el gasto sistémico; el cociente entre ambos es el cociente Qp/Qs. Después del nacimiento, en condiciones normales el gasto pulmonar y el sistémico son prácticamente iguales, y el cociente Qp/Qs = 1. En los pacientes con cortocircuitos entre la circulación sistémica y la pulmonar este cociente se altera. Dependiendo de la localización del cortocircuito (intra o extracardiaco), y de las alteraciones estructurales o posquirúrgicas asociadas, la interpretación de los hallazgos es diferente. Revisamos el concepto de Qp/Qs, los métodos para calcularlo con especial énfasis en la RM, y el significado de los resultados obtenidos, haciendo hincapié en la relevancia de estos datos dependiendo de la patología de base y los procedimientos terapéuticos que se hayan realizado al paciente (AU)

Cardiac magnetic resonance imaging (cMRI) provides abundant morphological and functional information in the study of congenital heart disease. The functional information includes pulmonary output and systemic output; the ratio between these two (Qp/Qs) is the shunt fraction. After birth, in normal conditions the pulmonary output is practically identical to the systemic output, so Qp/Qs = 1. In patients with «shunts» between the systemic and pulmonary circulations, the ratio changes, and the interpretation of these findings varies in function of the location of the shunt (intracardiac or extracardiac) and of the associated structural or postsurgical changes. We review the concept of Qp/Qs; the methods to calculate it, with special emphasis on cMRI; and the meaning of the results obtained. We place special emphasis on the relevance of these findings depending on the underlying disease and the treatment the patient has undergone (AU)

Ventilation/Perfusion Positron Emission Tomography--Based Assessment of Radiation Injury to Lung.

PURPOSE: To investigate (68)Ga-ventilation/perfusion (V/Q) positron emission tomography (PET)/computed tomography (CT) as a novel imaging modality for assessment of perfusion, ventilation, and lung density changes in the context of radiation therapy (RT). METHODS AND MATERIALS: In a prospective clinical trial, 20 patients underwent 4-dimensional (4D)-V/Q PET/CT before, midway through, and 3 months after definitive lung RT. Eligible patients were prescribed 60 Gy in 30 fractions with or without concurrent chemotherapy. Functional images were registered to the RT planning 4D-CT, and isodose volumes were averaged into 10-Gy bins. Within each dose bin, relative loss in standardized uptake value (SUV) was recorded for ventilation and perfusion, and loss in air-filled fraction was recorded to assess RT-induced lung fibrosis. A dose-effect relationship was described using both linear and 2-parameter logistic fit models, and goodness of fit was assessed with Akaike Information Criterion (AIC). RESULTS: A total of 179 imaging datasets were available for analysis (1 scan was unrecoverable). An almost perfectly linear negative dose-response relationship was observed for perfusion and air-filled fraction (r(2)=0.99, P<.01), with ventilation strongly negatively linear (r(2)=0.95, P<.01). Logistic models did not provide a better fit as evaluated by AIC. Perfusion, ventilation, and the air-filled fraction decreased 0.75 ± 0.03%, 0.71 ± 0.06%, and 0.49 ± 0.02%/Gy, respectively. Within high-dose regions, higher baseline perfusion SUV was associated with greater rate of loss. At 50 Gy and 60 Gy, the rate of loss was 1.35% (P=.07) and 1.73% (P=.05) per SUV, respectively. Of 8/20 patients with peritumoral reperfusion/reventilation during treatment, 7/8 did not sustain this effect after treatment. CONCLUSIONS: Radiation-induced regional lung functional deficits occur in a dose-dependent manner and can be estimated by simple linear models with 4D-V/Q PET/CT imaging. These findings may inform future studies of functional lung avoidance using V/Q PET/CT.

Lung ventilation/perfusion scintigraphy in pulmonary capillary hemangiomatosis: A pattern to consider / Gammagrafía pulmonar de ventilación/perfusión en la hemangiomatosis capilar pulmonar: un patrón a considerar

Pulmonary capillary hemangiomatosis is a rare disease, characterized by small capillaries proliferation, leading to pulmonary hypertension. The authors report a case of pulmonary capillary hemangiomatosis, and discuss its diagnostic difficulties. Special attention is presented to ventilation/perfusion scintigraphy, given both its importance to the evaluation of pulmonary hypertension, and its referred limited usefulness in pulmonary capillary hemangiomatosis. The few published cases of ventilation/perfusion scintigraphy on this entity have showed different patterns, which are discussed. This case presents a pattern with augmented perfusion on lung bases and normal ventilation, which has been described by other authors as typical for pulmonary capillary hemangiomatosis. The authors consider important to retain this pattern, when evaluating pulmonary hypertensive patients, given not only its possible ability to help on pulmonary capillary hemangiomatosis diagnosis, but also mainly its risk of misinterpretation as a decreased perfusion on upper lung lobes, leading to erroneous diagnostic hypotheses (AU)

La hemangiomatosis capilar pulmonar constituye una enfermedad rara, caracterizada por la proliferación de pequeños capilares que originan una hipertensión pulmonar. Los autores presentan un caso de hemangiomatosis capilar pulmonar, debatiendo sus dificultades diagnósticas. Se presta una atención especial a la gammagrafía de ventilación/perfusión, dada su importancia para la evaluación de la hipertensión pulmonar y su utilidad limitada en la hemangiomatosis capilar pulmonar. Se discuten los pocos casos publicados de gammagrafía de ventilación/perfusión en esta entidad crónica, que han mostrado diferentes patrones. Este caso presenta un patrón con incremento de perfusión en las bases pulmonares y ventilación pulmonar normal, que ha sido descrito por otros autores como típico en la hemangiomatosis capilar pulmonar. Los autores consideran importante la identificación de este patrón al evaluar a los pacientes con hipertensión pulmonar, dado que podría suponer una ayuda, no sólo para el diagnóstico de la hemangiomatosis capilar pulmonar, sino también por el riesgo de interpretar mal el descenso de perfusión en los lóbulos pulmonares superiores, que puede conducir a unas hipótesis diagnósticas erróneas (AU)

Importancia de la gammagrafía de perfusión pulmonar en el trasplante de pulmón único / Importance of the lung perfusion scintigraphy in single lung transplantation

La gammagrafía de perfusión pulmonar con 99mTc-MAA ofrece una valiosa información de los pacientes que van a someterse a trasplante de pulmón único. El empleo de esta técnica nos permite evaluar y cuantificar la función relativa de ambos pulmones para seleccionar el órgano a trasplantar. Una vez que se ha realizado la cirugía, la gammagrafía de perfusión pulmonar representa un método diagnóstico para evaluar la evolución del órgano trasplantado. Dos pacientes que fueron sometidos a este procedimiento quirúrgico fueron estudiados en nuestro hospital. En ambos se realizó gammagrafía de perfusión pulmonar preoperatoria para la selección del órgano a trasplantar, y meses después de la cirugía se realizó el estudio gammagráfico para la evaluación de la función de perfusión del órgano trasplantado(AU)

Lung perfusion scintigraphy (LPS) with 99mTc-MAA gives valuable information about patients who will undergo a single lung transplantation. This technique makes it possible to evaluate and quantify the relative function of both lungs to select the organ to be transplanted. Once the surgery has been performed, the LPS represents a diagnostic method to study the status of the transplanted organ. Two patients who underwent single lung transplantation were studied in our hospital. In both cases, a pre-operative LPS was performed before surgery for selection of the organ to be transplanted and the scintigraphy study was performed a few months after transplantation to establish the perfusion function of the transplanted lung(AU)

Diagnóstico y tratamiento paliativo endovascular de un angiosarcoma de arteria pulmonar / Endovascular diagnosis and palliative treatment of a pulmonary artery angiosarcoma

No disponible

Hipertensión pulmonar: aportación de la TCMD al diagnóstico de sus distintos tipos / Pulmonary hypertension: The contribution of MDCT to the diagnosis of its different types

La hipertensión pulmonar (HP) es una enfermedad caracterizada por la progresiva afectación de los vasos pulmonares, lo que produce aumento de las resistencias vasculares y, como consecuencia, fallo ventricular derecho. La lesión vascular es el factor común a un amplio abanico de patologías y su resultado, la HP, un cuadro clínico grave de mal pronóstico, que agrava el curso normal de las enfermedades a las que se asocia (EPOC, colagenosis, sarcoidosis, cardiopatías congénitas o adquiridas…). El interés por diagnosticarla lo más precozmente posible se debe a que, actualmente, se dispone de fármacos que mejoran la calidad de vida y han disminuido la mortalidad de estos pacientes y que existen posibilidades quirúrgicas para algunos tipos de hipertensión como la tromboembólica crónica o la asociada a algunas cardiopatías congénitas con cortocircuitos izquierda-derecha. Ante una sospecha clínica de HP los métodos de imagen son los que confirman el diagnóstico, sugieren una causa, ayudan a seleccionar el tratamiento más adecuado y monitorizan la respuesta. En la actual revisión del tema se presenta la aportación de los diferentes métodos de imagen para el diagnóstico de la enfermedad, haciendo especial hincapié en la TC multidetector (TCMD), que ofrece la posibilidad de estudiar con una sola adquisición todos los órganos torácicos. Se revisan los signos radiológicos de HP y se establecen los criterios radiológicos actuales para etiquetar el tipo de hipertensión, según la clasificación de Dana Point, basados en el estudio de las alteraciones del parénquima pulmonar, mediastino, espacios pleurales y pericardio y en el estudio de las cámaras cardíacas (AU)

Pulmonary hypertension is characterized by progressive involvement of the pulmonary vessels that leads to increased vascular resistance and consequently to right ventricular failure. Vascular lesions are a common factor in a wide spectrum of diseases, and their result, pulmonary hypertension, is a severe clinical condition with a poor prognosis that worsens the normal course of the diseases to which it is associated (COPD, collagen disease, sarcoidosis, and congenital or acquired heart disease). It is important for pulmonary hypertension to be diagnosed as early as possible because nowadays drugs can reduce mortality and improve the quality of life; furthermore, some types of pulmonary hypertension (e.g., chronic thromboembolism and those associated with some congenital heart diseases like left-to-right shunt) can be treated surgically. In cases of suspected pulmonary hypertension, imaging methods can confirm the diagnosis, suggest a cause, help choose the most appropriate treatment, and monitor the response to treatment. This review describes the approach to pulmonary hypertension using different imaging techniques; special emphasis is given to the role of multidetector CT (MDCT), which makes it possible to study all the organs in the thorax in a single acquisition. We review the radiological signs of pulmonary hypertension and the current (Dana Point) radiological criteria for classifying the type of hypertension based on alterations in the lung parenchyma, mediastinum, pleural spaces, and pericardium, as well as on the study of the chambers of the heart (AU)

Estimation of overall pulmonary function after irradiation using dose-effect relations for local functional injury.

PURPOSE: To predict the pulmonary function 3-4 months after irradiation for malignant lymphoma from the three-dimensional (3-D) dose distribution. METHODS: Dose-effect relations for the relative reduction of local perfusion (Q) and local ventilation (V), were calculated in 25 patients, using correlated SPECT (Single Photon Emission Computed Tomography) and CT data. By combining the 3-D dose distribution of an individual patient with the dose-effect relations averaged over all patients, the average reduction of local Q and V (i.e., the overall response parameters) in the whole lung was estimated for each patient. Correlation coefficients were calculated between these overall response parameters and the change in standard lung function tests. In addition, the relation between the overall response parameters and the incidence of radiation pneumonitis was determined. RESULTS: The overall response parameter for perfusion was correlated with the change in standard lung function tests, with correlation coefficients varying between 0.53 (p = 0.007) and 0.71 (p < 0.001) for the change of Vital Capacity and Forced Expiratory Volume at 1 s, respectively. For the overall response parameter for ventilation similar correlations were observed. Four out of the 25 patients developed radiation pneumonitis; in these four patients the overall response parameter for perfusion was on average somewhat higher (13.2 +/- 1.4% (1 standard error of the mean)) than in patients without radiation pneumonitis (10.5 +/- 1.0%), but this difference was not significant. A higher incidence of radiation pneumonitis was observed for larger values of the overall response parameter for perfusion; in patient groups with an overall response parameter for perfusion of 0-5%, 5-10%, 10-15%, and 15-20%, the incidence of radiation pneumonitis was 0 (0/1), 10 (1/10), 13 (1/8) and 33% (2/6), respectively. CONCLUSION: By combining the 3-D dose distribution with the average dose-effect relations for local perfusion or ventilation, an overall response parameter can be calculated prior to irradiation, which is predictive for the radiation-induced change in the overall pulmonary function, and possibly for the incidence of radiation pneumonitis, in this group of patients.

[The value of lung perfusion scintigraphy in radiation pneumonitis in comparison with the diffusing capacity DLCO]. / Der Aussagewert der Lungenperfusionsszintigraphie bei der Strahlenpneumonitis im Vergleich zur Diffusionskapazität DLCO.

The value of lung perfusion scintigraphy (Tc99m) and lung diffusing capacity are compared with references to early detection of radiogenic pneumonitis. Perfusion scintigraphy completed by diffusing capacity is excellent suitable for early detection. Risk cases are recognized up to 40 days earlier than by X-ray. Severity of radiogenic pneumonitis can be diminished remarkable by prevention therapy.

The effect of thoracic irradiation for cancer of the breast on ventilation, perfusion and pulmonary permeability. A one-year follow-up.

Regional and overall lung function was studied in 14 women during a one-year follow-up after postmastectomy irradiation for cancer of the breast. The dose was 40 Gy in the chest wall and 20-40 Gy in the apex of the lung. Immediately after irradiation there was a slight increase in pulmonary clearance of 99TCm-DTPA compared to baseline values. This increase, however, was not restricted to the field of irradiation. Three months after irradiation there were regional defects in the ventilation and perfusion scintigrams in 11 of the patients. At the same time there was a greater decrease in total lung capacity, vital capacity and diffusion capacity for CO than in ventilation and perfusion. One year after irradiation the lung function impairment had only insignificantly regressed. It is concluded that local lung irradiation may cause persistent regional and generalized lung function impairment. The early increase in pulmonary clearance of 99Tcm-DTPA could not be used as a predictor of subsequent lung function impairment.

Regional lung function impairment following post-operative radiotherapy for breast cancer using direct or tangential field techniques.

We have compared the effect of tangential and direct irradiation on regional lung function in 22 consecutive patients with breast cancer, who had been treated by post-operative irradiation 3 months prior to the examination. The tangential technique (total dose 32-36 Gy, less than 5 Gy of the lung) was employed in eight of the patients, while the direct technique (total dose 40 Gy, 5-20 Gy to the lung) was used in the other 14. In the group that had been treated by the tangential technique, there was no impairment of the ventilation or perfusion of the irradiated lung compared with the contralateral lung. The radiographs of the thorax were all normal. In the group that had been treated by the direct technique, there was a reduction in both the ventilation and the perfusion in 12 of the patients (p less than 0.01). The radiographs of the thorax were abnormal in only seven of these 12 patients. In both groups the regional leakiness of the lungs was evaluated as the pulmonary clearance of inhaled nebulised 99Tcm-DTPA. Due to differences in smoking habits between and within the groups, the results were not conclusive. It is concluded that the regional lung function was not significantly affected by the tangential technique, in contrast to a pronounced and harmful effect of the direct technique.

The validity of different methods of analysis of 133Xe washout curves for the determination of lung function.

The influence of different mathematical methods on the analysis of 133Xe washout data, used in the assessment of lung function in the pig, were investigated. When the data were fitted using a bi-exponential or a bi-exponential plus a constant type equation, neither the two clearance rate constants nor the overall 50% clearance time were found totally appropriate for the study of lung function. A new two compartmental model for the in vivo clearance of 133Xe is proposed. The model assumes the whole blood as one compartment and the lung, including the pulmonary blood, as the second compartment. This suggests that the curvature of the xenon clearance curve is the result of recording the summation of the activities from the alveoli and the pulmonary blood and not, as previously described, due to the existence of two different sub-populations of alveoli.

Radionuclide evaluation of pulmonary function following hemithorax irradiation of normal dogs with 60Co or fast neutrons.

To assess the effects of therapeutic doses of radiation on regional pulmonary function, 28 dogs had serial chest radiographs and quantitative ventilation, perfusion, and aerosol studies at three-, six-, nine-, and twelve-month intervals after hemithorax irradiation with 60-Co-gamma photons or 15-MeV fast neutrons. Findings showed marked reductions in perfusion and aerosol deposition in the irradiated lungs of dogs in the high-dose photon and neutron groups and in the medium-dose neutron group. The effects of large photon and small neutron doses were similar (neutron RBE = 4.5). Radionuclide studies were found to be useful for detecting these alterations.