Regional cardiac sympathetic reinnervation in transplanted human hearts detected by123I-MIBG SPECT imaging

The purpose of this study was to assess the regional cardiac sympathetic reinnervation late (> or = 1 year) after heart transplantation (HTX) by means of 123I-MIBG (MIBG) scintigraphy. Eight patients with a pretransplantation diagnosis of idiopathic dilated cardiomyopathy underwent MIBG scintigraphy more than one year after HTX. The presence or absence of regional MIBG uptake was evaluated in each SPECT image, and global MIBG uptake was semi-quantitatively assessed by the heart to mediastinum ratio (H/M). Five of 8 patients had visible MIBG uptake in both planar and SPECT images (PU group), whereas 3 of 8 patients had no uptake, 2 of them after a period of 2 years, and one of them as long as 5 years after HTX, respectively (NU group). Positive regional MIBG uptake involved the basal anterior region in all 5 patients, the basal septal region in 4 patients, the basal lateral region in 3 patients and the basal posterior region in 1 patient. The H/M value was 1.24+/-0.10 in the PU group and 1.09+/-0.03 in the NU group. In conclusion, MIBG SPECT can detect regional sympathetic reinnervation, indicating that basal septal and lateral regions next to the basal anterior are more likely to be reinnervated, but reinnervation is much less likely to occur in the midventricular and apical regions.     

High-tension electrical injury to the heart as assessed by radionuclide imaging

To evaluate cardiac complications associated with electrical injury, 7 patients with high-tension electrical injury (6,600 V alternating current) underwent 201Tl and 123I-metaiodobenzylguanidine (MIBG) imaging in addition to conventional electrocardiographic and echocardiographic assessments. Electrocardiography showed transient atrial fibrillation, second degree atrioventricular block, ST-segment depression, and sinus bradycardia in each patient. Echocardiography showed mild hypokinesis of the anterior wall in only 2 patients, but 201Tl and 123I-MIBG myocardial scintigraphy showed an abnormal scan image in 6/7 and 5/6 patients, respectively. Decreased radionuclide accumulation was seen primarily in areas extending from the anterior wall to the septum. Decreased radionuclide accumulation was smaller in extent and milder in degree in 123I. MIBG than in 201Tl imaging. These results suggest that even in patients without definite evidence of severe cardiac complications in conventional examinations, radionuclide imaging detects significant damage due to high-tension electrical injury, in which sympathetic nerve dysfunction might be milder than myocardial cell damage.     

Homocysteine levels are associated with the results of <Superscript>123</Superscript>I-metaiodobenzylguanidine myocardial scintigraphy in type 2 diabetic patients

Purpose Elevated total plasma homocysteine (tHcy) levels and cardiovascular autonomic dysfunction are associated with a high mortality in type 2 diabetic patients. We tested the hypothesis that hyperhomocysteinemia is associated with insulin resistance and cardiovascular autonomic dysfunction in type 2 diabetic patients not receiving insulin treatment. Methods The study group consisted of 17 type 2 diabetic patients with high tHcy levels (>15 mmol/l, age 58±5 years, high tHcy group). The control group consisted of 23 age-matched type 2 diabetic patients with normal tHcy levels (≤15 mmol/l, age 58±9 years, normal tHcy group). Cardiovascular autonomic function was assessed by baroreflex sensitivity, heart rate variability, plasma norepinephrine concentrations, and cardiac ¹²³I-metaiodobenzylguanidine (MIBG) scintigraphy. Results Early and delayed ¹²³I-MIBG myocardial uptake values were lower (p<0.005 and p<0.01, respectively) and the percent washout rate of ¹²³I-MIBG was higher (p<0.001) in the high tHcy group than in the normal tHcy group. The fasting plasma insulin concentrations (p<0.0001) and the homeostasis model assessment (HOMA) index values (p<0.0001) were higher in the high tHcy group than in the normal tHcy group. Multiple regression analysis revealed that the level of tHcy was independently predicted by the HOMA index values and the myocardial uptake of ¹²³I-MIBG at the delayed phase. Conclusion Our results demonstrate that high levels of tHcy are associated with depressed cardiovascular autonomic function and insulin resistance in patients with type 2 diabetes mellitus.     

Detection of metastatic lesions from malignant pheochromocytoma and paraganglioma with diffusion-weighted magnetic resonance imaging: comparison with 18F-FDG positron emission tomography and 123I-MIBG scintigraphy

OBJECTIVE: To investigate the diagnostic features of whole-body diffusion-weighted magnetic resonance imaging (DWI) as compared with 2-[(18)F]-fluoro-2-deoxy-D-glucose positron emission tomography (FDG-PET) and (123)I-meta-iodo-benzyl guanidine scintigraphy (MIBG) on metastatic lesions of patients with malignant pheochromocytoma or paraganglioma. METHODS: We prospectively studied 11 patients with histologically confirmed pheochromocytoma/paraganglioma and possible metastatic lesions. FDG-PET, MIBG, and DWI examinations were performed within 1 week, and the images were visually interpreted. Abnormal positive uptake either on MIBG or on FDG-PET was considered as metastases. Abnormal high signal intensities on DWI were considered as metastases using conventional T1-and T2-weighted images as reference. RESULTS: FDG-PET and DWI demonstrated metastatic lesions in all 11 patients, but MIBG showed no metastatic lesions in two patients. The numbers of lymph node metastases depicted on FDG-PET, MIBG, and DWI were 19, 6, and 39; bone metastases were 50, 49, and 60; liver metastases were 9, 9, and 15; lung metastases were 5, 7, and 5, respectively. MIBG failed to demonstrate many metastatic lesions, which were demonstrated on FDG-PET or DWI, although two mediastinal lymph node metastases, three lung metastases, and six bone metastases, which were not seen on DWI, were clearly demonstrated on MIBG. DWI showed 15 liver metastases, but 6 of them were not seen on FDG-PET or MIBG. CONCLUSIONS: DWI may be particularly advantageous in depicting lymph node and liver metastases and may have a higher rate of detecting metastatic lesions when compared with MIBG or FDG-PET. The limitations of DWI were possible false-positive finding, and probable lower detectability of mediastinal lymph node and lung metastasis.     

Prolonged lung retention of 123I-IMP in pulmonary disease

The accumulation of venously injected ¹²³I-IMP in the lung was studied. Between 30 and 50 min after the injection of the 1.5 mCi ¹²³I-IMP, the concentration of ¹²³I-IMP in the broncho-alveolar lavage fluid were much higher than in the blood. It was considered that ¹²³I-IMP was transported into the alveolar spaces and was absorbed by the alveolar cells. The half time (T _1/2) of the ¹²³I-IMP release from the lung between 10 and 25 min immediately after the injection was calculated. In normal subjects the T _1/2 ranged between 25 and 44 min and was prolonged in subjects with pulmonary fibrosis, sarcoidosis, and allergic alveolitis. It was considered that the retention of ¹²³I-IMP was related not only to the endothelial cells, but also to the alveolar cells. It was considered that the analysis of the lung release of ¹²³I-IMP forms a new lung dysfunction index.     

Usefulness of<Superscript>123</Superscript>I-metaiodobenzylguanidine myocardial scintigraphy in the prediction of cardiac events in patients with cardiomyopathy showing stabilization of symptoms or preserved cardiac function

OBJECTIVE: It is not rare for patients with cardiomyopathy to be asymptomatic for long periods or to show improved cardiac function following various medical interventions. Conversely, cardiac events sometimes occur in those patients, requiring close observation. We assessed the usefulness of 123I-metaiodobenzylguanidine myocardial scintigraphy (MIBG) to predict the occurrence of cardiac events in patients with stable cardiomyopathy. METHODS: The subjects comprised 74 outpatients with stable cardiomyopathy. MIBG was performed calculate the extent score, severity score, washout rate (WR), and heart-to-mediastinum ratio. At about the same time, the left ventricular ejection fraction (LVEF) by echocardiography and the plasma brain natriuretic peptide were measured. The mean observation period extended for 741+/-437 days with an end point of cardiac events (cardiac death, heart failure requiring hospitalization, and arrhythmias requiring hospitalization). RESULTS: During the mean follow-up period, 15 cardiac events occurred. Results of multivariate analysis revealed that LVEF was the most powerful predictor of cardiac events (0.006, p < 0.01). However, WR was the only significant predictor of hard events such as cardiac death (1.171, p < 0.001) and cardiac events in the group of patients who preserved cardiac function with LVEF 0.4 or higher (1.079, p < 0.05). CONCLUSION: Combined use of LVEF and WR is useful to predict the occurrence of cardiac events in patients with stable cardiomyopathy.     

Quantitation of cardiac sympathetic innervation in rabbits using 11C-hydroxyephedrine PET: relation to 123I-MIBG uptake

Purpose Although ¹¹C-hydroxyephedrine (¹¹C-HED) PET is used to map cardiac sympathetic innervation, no studies have shown the feasibility of quantitation of ¹¹C-HED PET in small- to medium-sized animals. Furthermore, its relation to ¹²³I-MIBG uptake, the most widely used sympathetic nervous tracer, is unknown. The aims of this study were to establish in vivo sympathetic nerve imaging in rabbits using ¹¹C-HED PET, and to compare the retention of ¹¹C-HED with that of ¹²³I-MIBG.Methods Twelve rabbits were assigned to three groups; control (n=4), chemical denervation by 6-hydroxydopamine (6-OHDA) (n=4) and reserpine treated to inhibit vesicular uptake (n=4). After simultaneous injection of ¹¹C-HED and ¹²³I-MIBG, all animals underwent dynamic ¹¹C-HED PET for 40 min with arterial blood sampling. The ¹¹C-HED retention fraction and normalised ¹¹C-HED activity measured by tissue sampling were compared with those measured by PET.Results Both the ¹¹C-HED retention fraction and the normalised ¹¹C-HED activity measured by PET correlated closely with those measured by tissue sampling (R=0.96027, p<0.001 and R=0.97282, p<0.001, respectively). Inhibition study by 6-OHDA resulted in a significant reduction in retention (90%) for both ¹¹C-HED and ¹²³I-MIBG. Reserpine pretreatment reduced ¹¹C-HED retention by 50%, but did not reduce ¹²³I-MIBG retention at 40 min after injection.Conclusion Non-invasive quantitation of cardiac sympathetic innervation using ¹¹C-HED PET is feasible and gives reliable estimates of cardiac sympathetic innervation in rabbits. Additionally, although both ¹¹C-HED and ¹²³I-MIBG are specific for sympathetic neurons, ¹¹C-HED may be more specific for intravesicular uptake than ¹²³I-MIBG in some situations, such as that seen in reserpine pretreatment.     

Use of iodine-123 metaiodobenzylguanidine scintigraphy for the detection of amiodarone induced pulmonary toxicity in a rabbit model: A comparative study with technetium-99m diethyltriaminepenta acetic acid radioaerosol scintigraphy

The purpose of the study was; (i) to determine whether 123I-MIBG scintigraphy is sensitive for detection of amiodarone induced pulmonary toxicity (AIPT) and (ii) to compare it with 99mTc-DTPA radioaerosol. Twelve white New Zealand rabbit with initial mean body weight 4.24 +/- 0.47 g were divided into two groups. AIPT group (n = 7) was administered amiodarone (20 mg/kg BW). The control group (n = 5) received the same amount of 0.9% saline. All animals underwent 123I-MIBG and 99mTc-DTPA radioaerosol scintigraphy at the end of the treatment period. 123I-MIBG static thorax images were obtained during 10 minutes at 15 minutes and 3-hours after intravenous injection of the radiopharmaceutical. Lung to heart ratios (LHR) and lung to mediastinum ratios (LMR), and retention index (LRI) of 123I-MIBG were determined. Two days after 123I-MIBG scintigraphy, 99mTc-DTPA radioaerosol scintigraphy was performed, and clearance from the lungs was measured for 10 min (1 min/frame) following termination of inhalation. 123I-MIBG lung retention index (LRI) was significantly higher in the AIPT group than the control (61 +/- 4.6 vs. 40 +/- 4.5, p = 0.01). Early LHR and LMR were significantly lower in the AIPT group than in the control group (p = 0.04, p = 0.01, respectively), whereas those of late LHR and LMR were not significantly different. T1/2 values of DTPA clearance were significantly increased in AIPT group according to the control group (55 +/- 7.2 vs. 86.6 +/- 18.5, p = 0.02). 123I-MIBG scintigraphy is a valuable tool for detecting AIPT in a rabbit model. Additionally, 99mTc-DTPA radioaerosol scintigraphy is an excellent comprehensive investigational tool for detecting AIPT with the added advantage of lower cost.     

Abdominal visceral fat accumulation is associated with the results of <Superscript>123</Superscript>I-metaiodobenzylguanidine myocardial scintigraphy in type 2 diabetic patients

Purpose We tested the hypothesis that increased abdominal visceral accumulation (VFA) is associated with insulin resistance and cardiovascular autonomic dysfunction in type 2 diabetic patients not receiving insulin treatment. Methods The fat distribution was evaluated by measuring the VFA by abdominal computed tomography at the umbilical level. The study group consisted of 24 type 2 diabetic patients with high VFA (≥100 cm², age 60 ± 8 years, high VFA group). The control group consisted of 19 age-matched type 2 diabetic patients with normal VFA (<100 cm², age 60 ± 7 years, normal VFA group). Cardiovascular autonomic function was assessed by baroreflex sensitivity, heart rate variability, plasma norepinephrine concentrations, and cardiac ¹²³I-metaiodobenzylguanidine (MIBG) scintigraphy. Results Early and delayed ¹²³I-MIBG myocardial uptake values were lower (p < 0.005 and p < 0.0001, respectively) and the percent washout rate of ¹²³I-MIBG was higher (p < 0.0005) in the high VFA group than in the normal VFA group. The fasting plasma insulin concentrations (p < 0.005) and the homeostasis model assessment (HOMA) index values (p < 0.0005) were higher in the high VFA group than in normal VFA group. Multiple regression analysis revealed that the level of VFA was independently predicted by the HOMA index values and the myocardial uptake of ¹²³I-MIBG during the delayed phase. Conclusion Our results demonstrate that the level of VFA is associated with depressed cardiovascular autonomic function and insulin resistance in patients with type 2 diabetes mellitus.     

Evaluation of 123I-orthoiodohippurate single kidney clearance rate by renal sequential scintigraphy in a large cohort of likely normal subjects aged between 0 and 18 years

Purpose Age-related values of ¹²³I-orthoiodohippurate (OIH) single kidney clearance rate (Cl) were estimated in a large cohort of likely normal children aged between 0 and 18 years. Methods Among 4,111 children examined in the past 10 years, 917 were selected with the following inclusion criteria: (a) mild ultrasonographic hydronephrosis with right differential renal function (DRF) <53% and >47% (498 pts), (b) known or suspected urinary tract infection with normal ultrasound, serum creatinine and DMSA and DRF <53% and >47% (419 pts). ¹²³I-OIH-Cl was assessed using a validated gamma camera method. Children were divided into 21 age classes: from 0 to 2 years, eight 3-month classes; from 2 to 14 years, twelve 1-year classes; from 14 to 18 years, one 4-year class. Results Cl, plotted against age, was fitted using an increasing function (). Mean ¹²³I-OIH-Cl of 1,834 kidneys was 306±22 ml/min/1.73 m² BSA. Mean ¹²³I-OIH-Cl of the right and left kidneys was 307±23 and 305±22 ml/min/1.73 m² BSA, respectively (p<0.002). The best-fitting ¹²³I-OIH-Cl growing function was: Cl=311−230e−0.69×Age (months). ¹²³I-OIH-Cl improved progressively starting from birth, reaching 96% and 98% of the mature value at 1 and 1.5 years, respectively. ¹²³I-OIH-Cl at birth (age=0) was 81 ml/min/1.73 m² BSA. After 18.6 days of life, the renal function had doubled its starting value, and it reached a plateau of 311 ml/min/1.73 m² BSA at 2 years. Conclusion This work represents a systematic evaluation of ERPF by a gamma camera method in a large cohort of selected likely normal paediatric subjects. This work is written in memory of Prof. Ugo Meldolesi, our nephrology nuclear medicine mentor and friend.     

Relation between myocardial response to dobutamine stress and sympathetic nerve activation in patients with idiopathic dilated cardiomyopathy: A comparison of123I-MIBG scintigraphic and echocardiographic data

It is likely that a close association exists between findings obtained by two methods: dobutamine stress echocardiography and 123I-MIBG scintigraphy. Both of these methods are associated with beta-adrenergic receptor mechanisms. This study was conducted to demonstrate the relation between myocardial response to dobutamine stress and sympathetic nerve release of norepinephrine in the failing heart. In 12 patients with heart failure due to idiopathic dilated cardiomyopathy, the myocardial effects of dobutamine stress were evaluated by low-dose dobutamine stress echocardiography: and sympathetic nerve function was evaluated by scintigraphic imaging with iodine-123 [123I] meta-iodobenzylguanidine (MIBG), an analogue of norepinephrine. Echocardiography provided quantitative assessment of wall motion and left ventricular dilation; radiotracer studies with 123I-MIBG provided quantitative assessment of the heart-to-mediastinum (H/M) uptake ratio and washout rate. Results showed that H/M correlated with baseline wall motion (r = 0.682, p = 0.0146), wall motion after dobutamine stress (r = 0.758, p = 0.0043), the change in wall motion (r = 0.667, p = 0.0178), and with left ventricular diastolic diameter (r = 0.837, p = 0.0007). In addition, the 123I-MIBG washout rate correlated with baseline wall motion (r = 0.608, p = 0.0360), wall motion after dobutamine stress (r = 0.703, p = 0.0107), and with the change in wall motion (r = 0.664, p = 0.0185). Wall motion, especially in the myocardial response to dobutamine stress, is related to sympathetic nerve activity in heart failure.     

131I-metaiodobenzylguanidine uptake in the isolated rat lung: A potential marker of endothelial cell function

The pulmonary vascular endothelial cell plays an important role in the uptake of circulating biogenic amines. In cultured adrenomedullary cells, metaiodobenzylguanidine (MIBG) and norepinephrine (NE) are taken up by the same sodium-dependent active transport system. To examine whether a similar process occurs in the lung, the mechanism of single pass ¹³¹I-MIBG accumulation was studied in rat lungs perfused with a Krebs-Ringer bicarbonate buffer containing 4.5% bovine albumin. MIBG lung accumulation was measured as the percent extraction per g of lung tissue. In control experiments the extraction was 19.7±2.3%/g (n=38) using a perfusate containing 0.01 M MIBG. MIBG accumulation was significantly depressed (% decrease from control) by: cold media at 4° C (84%), 0.5 mM ouabain (67%), 10 M imipramine (70%), 0.7 M serotonin (22%) and 40 mM K⁺ (48%). Pulmonary uptake of MIBG was characterized by Michaelis-Menten kinetics (K _m=0.92×10^-6 M and V _max=2.09×10^-9 moles/g per min). The addition of NE (0.5 M) also altered MIBG uptake such that the K _m and V _max became 0.52×10^-6 M and 0.93×10^-9 moles/g per min, respectively. The results indicate that MIBG accumulation in the lung involves sodium-dependent, energy-requiring, active transport mechanisms similar to those known to exist for norepinephrine, and suggest that MIBG may be useful as a marker of pulmonary endothelial cell function.     

血管内皮细胞分泌的炎性递质在急性肺损伤发病机制中的作用

肺血管内皮细胞损伤在急性肺损伤（ALI）／急性呼吸窘迫综合征（ARDS）的病理过程中起重要作用,各种血管源性炎症递质可导致血管内皮细胞损伤,提高肺泡-毛细血管通透性,肺血管间质和肺泡腔水肿,发生顽固性低氧血症、呼吸窘迫等临床表现。本文探讨了ALI时各种炎症递质的表达、对肺血管内皮的作用机制及对ALI的病理生理影响。这些可能成为ALI／ARDS新的治疗靶点和研究的方向。     

Simultaneous assessment of Tc-99m-sestamibi and I-123-BMIPP myocardial distribution in patients with myocardial infarction: Evaluation of left ventricular function with ECG-gated myocardial SPECT

123I-labeled 15-(p-iodophenyl)-3R,S-methyl pentadecanoic acid (BMIPP) is a branched-chain free fatty acid that is used to evaluate various cardiac diseases. The aim of the present study was to investigate the relationship between myocardial perfusion (99mTc-sestamibi) and BMIPP uptake, and to correlate perfusion and metabolic alterations with regional left ventricular dysfunction in patients with myocardial infarction (MI). ECG-gated dual-isotope myocardial SPECT was performed on 130 patients with MI with sestamibi (555 MBq) and BMIPP (148 MBq). The patients were classified into 3 groups according to PTCA therapy and the interval between the onset of infarction and RI injection (OR time). Group A (n = 56) included patients whose OR time was less than one month and who had undergone successful PTCA, Group B (n = 36) had OR times of less than one month and had conservative medical therapy, and Group C (n = 38) had OR times of over one month. The severity scores of the dual-isotope images were calculated from the defect scores in 9 segments. From the ECG-gated SPECT data with sestamibi, the left ventricular ejection fraction (LVEF; %) and regional wall motion were determined automatically using the QGS program LVEF obtained from gated SPECT correlated well with the severity scores for sestamibi and BMIPP (r = -0.68 and -0.76, respectively). The delta severity scores (BMIPP scores - sestamibi scores) of Group A were significantly higher than those of the other two groups (3.6 +/- 3.0 vs. 1.5 +/- 1.7 and 1.0 +/- 1.4, p < 0.001 ). The rate of dysfunctional segments with normal sestamihi distribution was significantly higher in Group A than in Group C (20.7% vs. 6.7%, p < 0.001). ECG-gated dual-isotope SPECT is useful since myocardial perfusion, fatty acid metabolism and left ventricular function can be analyzed during a single examination, so that this procedure has the potential to provide comprehensive information when evaluating patients with ischemic heart disease.     

Quantitation of dopamine transporter blockade by methylphenidate: first in vivo investigation using [123I]FP-CIT and a dedicated small animal SPECT

Purpose The aim of this study was to investigate the feasibility of assessing dopamine transporter binding after treatment with methylphenidate in the rat using a recently developed high-resolution small animal single-photon emission computed tomograph (TierSPECT) and [¹²³I]FP-CIT.Methods [¹²³I]FP-CIT was administered intravenously 1 h after intraperitoneal injection of methylphenidate (10 mg/kg) or vehicle. Animals underwent scanning 2 h after radioligand administration. The striatum was identified by superimposition of [¹²³I]FP-CIT scans with bone metabolism and perfusion scans obtained with ^99mTc-DPD and ^99mTc-tetrofosmin, respectively. As these tracers do not pass the blood–brain barrier, their distribution permits the identification of extracerebral anatomical landmarks such as the orbitae and the harderian glands. The cerebellum was identified by superimposing [¹²³I]FP-CIT scans with images of brain perfusion obtained with ^99mTc-HMPAO.Results Methylphenidate-treated animals and vehicle-treated animals yielded striatal equilibrium ratios (V₃) of 0.24±0.26 (mean ± SD) and 1.09±0.42, respectively (t test, two-tailed, p<0.0001). Cortical V₃ values amounted to 0.05±0.28 (methylphenidate) and 0.3±0.39 (saline, p=0.176). This first in vivo study of rat dopamine transporter binding after pre-treatment with methylphenidate showed a mean reduction of 78% in striatal [¹²³I]FP-CIT accumulation.Conclusion The results can be interpreted in terms of a pharmacological blockade in the rat striatum and show that in vivo quantitation of dopamine transporter binding is feasible with [¹²³I]FP-CIT and the TierSPECT. This may be of future relevance for in vivo investigations on rat models of attention deficit/hyperactivity disorder. Furthermore, our findings suggest that investigations in other animal models, e.g. of Parkinsons and Huntingtons disease, may be feasible using SPECT radioligands and small animal imaging systems.     

Correlation of FDG-PET findings with histopathology in the assessment of response to induction chemoradiotherapy in non-small cell lung cancer

Purpose The objective of this study was to evaluate the ability of FDG-PET to predict the response of primary tumour and nodal disease to preoperative induction chemoradiotherapy in patients with non-small cell lung cancer (NSCLC).Methods FDG-PET studies were performed before and after completion of chemoradiotherapy prior to surgery in 26 patients with NSCLC. FDG-PET imaging was performed at 1 h (early) and 2 h (delayed) after injection. Semi-quantitative analysis was performed using the standardised uptake value (SUV) at the primary tumour. Percent change was calculated according to the following equation: . Based on histopathological analysis of the specimens obtained at surgery, patients were classified as pathological responders or pathological non-responders. The clinical nodal stage on the post-chemoradiotherapy PET scan was visually determined and compared with the final pathological stage.Results Eighteen patients were found to be pathological responders and eight to be pathological non-responders. SUV_after values from both early and delayed images in pathological responders were significantly lower than those in pathological non-responders. The percent change values from early and delayed images in the pathological responders were significantly higher than those in the pathological non-responders. The post-chemoradiotherapy PET scan accurately predicted nodal stage in 22 of 26 patients.Conclusion FDG-PET may have the potential to predict response to induction chemoradiotherapy in patients with NSCLC.     

Assessment of mean transit time in the engrafted lung with <Superscript>133</Superscript>Xe lung ventilation scintigraphy improves diagnosis of bronchiolitis obliterans syndrome in living-donor lobar lung transplant recipients

Objective Staging of bronchiolitis obliterans syndrome (BOS) following lung transplantation is based on declines in forced expiratory volume in 1 s (FEV₁). The aim of this study was to evaluate the usefulness of ¹³³Xe ventilation scintigraphy in the early detection of BOS following living-donor lobar lung transplantation (LDLLT), to compare ¹³³Xe washout imaging with computed tomography (CT) findings for early detection of BOS following LDLLT, and to evaluate ¹³³Xe washout imaging by quantitative analyses. Methods Subjects comprised 30 double-lung recipients and 1 single-lung recipient, who had undergone LDLLT at our institution and survived more than 1 year. Clinically diagnosed BOS developed in six recipients. Declines in graft function were evaluated using a combination of three methods, namely, dynamic spirometry, high-resolution CT (HRCT), and ¹³³Xe ventilation scintigraphy. Findings for all transplanted lungs were compared between CT and ¹³³Xe washout imaging. ¹³³Xe washout imaging was assessed using mean transit time (MTT) of bi-and unilateral lungs. Correlations between MTT of bilateral lungs and FEV₁% were evaluated. Differences in MTT between BOS and non-BOS lungs, and between non-BOS and donor lungs were also evaluated on unilateral lungs. Appropriate cut-off values of MTT of unilateral lungs were set for the diagnosis of BOS. Results In all six BOS cases, prolonged-washout images of engrafted lungs revealed early-phase BOS with declines from baseline FEV₁, whereas only one BOS case could be detected using early CT findings of BO (bronchodilatation, decrease in number and size of pulmonary vessels, thickening of septal lines, and volume reduction). A significant correlation was identified between MTT and FEV₁% (r = −0.346, P < 0.0001). MTT of unilateral lungs was significantly longer in BOS lungs than in non-BOS lungs (P < 0.0001). The cut-off MTT of unilateral lungs for the diagnosis of BOS was set at 64.77 s. Conclusions Our data show that ¹³³Xe washout imaging offers excellent potential for early detection of BOS compared with early CT findings. Using ¹³³Xe washout imaging and MTT with radioactive tracer offers a noninvasive indication of selective ventilatory function in engrafted lungs following LDLLT. MTT appears useful for identifying BOS following LDLLT and allows quantitative evaluation of graft function in unilateral lungs.     

基于双能量CT肺灌注成像的相对强化值评估肺动脉栓塞短期预后的价值

目的:探讨基于双能量CT肺灌注成像的肺实质相对强化值在评估肺动脉栓塞短期预后中的临床应用价值.方法:45例经双能量CT肺灌注成像证实的肺动脉栓塞患者纳入本研究.根据短期临床预后结果分为预后不良组(n=24)和预后良好组(n=21).利用双能量后处理软件lung PBV计算全肺的相对强化值.采用Mann-Whitney U检验比较两组相对强化值的差异,采用受试者工作特征曲线(ROC)分析该指标的最佳诊断阈值,并计算该阈值的诊断效能.结果:预后不良组的相对强化值(34.4％±7.0％)明显低于预后良好组(118.6％±13.1％),差异有统计学意义(Z=3.6,P＜0.05).ROC曲线下面积为0.813,相对强化值的最佳诊断阈值为67％,该阈值诊断肺栓塞短期预后的敏感度为70.8％,特异度为81％.结论:基于双能量CT肺灌注成像的肺实质相对强化值能够有效预测肺动脉栓塞的短期预后,可作为肺动脉栓塞短期预后的评估参数.     

偏二甲基肼和四氧化二氮吸入性肺损伤中肺泡表面活性物质的变化

目的研究火箭液体推进剂偏二甲基肼（UDMH）和四氧化二氮（N2O4）吸入性急性肺损伤（ALI）中肺泡表面活性物质（PS）的变化及其与ALI的关系。方法84只大鼠分为对照组和5个实验组。实验组在静式染毒柜内分别吸入UDMH（0．98g／m^3）和N2O4（0．19g／ms）各10min，间隔10min。实验组在吸入后2、6、12、24、48h分别处死。测定各组大鼠常压下支气管肺泡灌洗液（BALF）的表面张力（γ）、加压下最低表面张力（γmin）、磷脂酰胆碱（PC）和磷脂酰乙醇胺（PE）。同时测定肺组织湿／于重比（W／D）、BALF中总蛋白和乳酸脱氢酶（LDH）等肺损伤指标，评价病理学改变。结果UDMH-N2O4吸入性ALI表现为肺W／D比值增加、BALF中总蛋白和LDH升高，以及肺水肿、肺间隔增厚等病理变化。PS的异常表现为：①在UDMH—N2O4吸入后2hBALF中γ和γmin。即明显升高，至24-48h尚未恢复到对照组水平；②吸入后24hBALF中PC明显低于对照组，PE含量明显高于对照组。以BALF中总蛋白作为肺损伤指标与PS异常的指标γ和γmin分别做直线相关分析，相关系数分别为0．435（P〈0．01）和0．419（P〈0．01）。结论UDMH—N2O4吸入性ALI中存在PS异常，PS异常可能参与了UDMH—N2O4吸入性ALI的发生发展过程。     

18F-FDG PET/CT引导局部晚期非小细胞肺癌靶区剂量提升的可行性研究

目的 研究基于放疗前正电子发射计算机断层显像（PET/CT）的标准摄取值（SUV）梯度引导局部晚期非小细胞肺癌（NSCLC）患者靶向剂量提升的可行性及剂量学特点。方法 收集29例NSCLC患者的放疗前PET/CT图像,在PET/CT图像上勾画大体肿瘤靶区（GTV）,以最大SUV值（SUV_max）的50%和75%为阈值将GTV分割为3个代谢活性亚区域,低于50%SUV_max的区域为GTV1,50%SUV_max到75%SUV_max的区域为GTV2,高于75%SUV_max的区域为GTV3。计划靶区（PTV）、PTV1、PTV2、PTV3分别由GTV、GTV1、GTV2及GTV3外放适当边界得到。计划1：在PTV上照射均匀60 Gy处方剂量。计划2：将PTV1、PTV2和PTV3的处方剂量分别设置为60~66 Gy、66~72 Gy和≥72 Gy。比较两种治疗计划靶区和危及器官（OAR）的剂量学差异。结果 相对于计划1,计划2将2%的PTV体积接受的剂量（D₂）由66.5 Gy提升至78.5 Gy,剂量提升约20%;PTV的平均剂量提升了8.9%（63.2~68.8 Gy）、PTV1,PTV2、PTV3的平均剂量分别提升了2.8%（62.7~64.4 Gy）、10.3%（63.5~70.0 Gy）、18.7%（63.8~75.8 Gy）。各亚区域剂量均得到有效提升。计划1与计划2 中PTV的60 Gy剂量线靶区覆盖度基本相当,差异无统计学意义（P>0.05）,均匀性指数（HI）的差异有统计学意义（t=23.3, P<0.05）,计划2中随着最大剂量的提升,HI下降显著。肺、心脏和脊髓的受照剂量在两个治疗计划中基本相当,差异均无统计学意义（P>0.05）。结论 对不同代谢活性梯度实施差异化的放疗剂量,在不增加危及器官辐射剂量的前提下,可对代谢活性高的亚区域进行靶向剂量提升,具有提高肿瘤局部控制的潜能。