Potential of iodine-123 metaiodobenzylguanidine single-photon emission tomography to detect abnormal functional status of the pulmonary neuroadrenergic system in irradiated lung.

The potential of iodine-123 metaiodobenzylguanidine (MIBG) to detect functional abnormalities of the pulmonary neuroadrenergic system (PNS) in irradiated lung areas (ILAS) was preliminarily explored using single-photon emission tomography (SPET). The subjects included five healthy subjects and a total of 31 patients with peripheral-type lung cancer treated by radiation; 15 patients (group A) had received a dose of less than 36 Gy (mean +/- SD: 28.2 +/-6.2 Gy), and 16 patients (group B) had received a higher dose (mean +/- SD: 51.2 +/- 3.5 Gy) at the time of examination. MIBG SPET scans acquired 15 min and 3 h after injection were used to measure the MIBG uptake ratio (count ratio of the ILA to the contralateral non-ILA) and the clearance rate [percentage of (early counts - delayed counts)/early counts] from the ILAs without noticeable abnormal opacities on chest computed tomography scan. Lung perfusion changes were also assessed by technetium-99m macroaggregated albumin SPET. By contrast to the homogeneous MIBG uptake in the lungs of the healthy subjects, MIBG uptake was folcally decreased in correspondence with the ILAs in all patients, including 11 patients (73.3%) of group A with relatively preserved lung perfusion. The reduction MIBG uptake was significant (P<0.0001), and the MIBG clearance rate from the ILAs was also significantly faster than the clearance rates from the normal lungs and contralateral non-ILAs (both P<0.01). Group B patients showed significantly lower MIBG uptake and faster clearance from the ILAs than group A patients (P<0. 001 and P<0.05, respectively), although there was no significant difference in the clearance from the non-ILAs. Overall, MIBG uptake/clearance from the ILAs correlated significantly with the radiation dose in the 31 patients (r = -0.656; P<0.0001 and r = 0. 387; P<0.05, respectively). Perfusion changes were inversely correlated with the clearance from the ILAs (r = -0.432, P<0.05), but did not correlate with MIBG uptake. These preliminary results suggest that MIBG may have the potential to be a marker of abnormal functional status of the PNS produced by irradiation and may facilitate investigation of irradiation lung injury independently of morphological or lung perfusion changes.

The effects of new platelet inhibitory drug E-5510 on platelet deposition on aortic bifurcation grafts: assessment by indium-111-oxime labeled platelet imaging.

The effects of a recently synthesized anti-platelet aggregation drug (E-5510) on platelet deposition in a knitted Dacron aortic graft underwent preliminary evaluation by In-111 oxime labeled platelet imaging. Seven patients undergoing aortofemoral bypass using this graft for occlusive disease were randomized into two groups: those receiving E-5510 and those receiving no medication. This agent was administered for 17 days postoperatively, and on the 14th day In-111 platelets were injected and images were acquired at 24, 48, and 72 hours. Platelet deposits in the grafts were assessed by the ratios of graft radioactivity to that of the adjacent native iliac arteries. Platelet deposition at the sites of anastomosis and deposition along the entire graft were normalized by initial deposition at 24 hours, and had significantly decreased at 72 hours in the three treated patients, while the normalized deposition increased progressively over time in the remaining four nonmedicated patients. E-5510 seems to have the potential to inhibit excessive platelet deposition on recently implanted grafts.

Splenic hamartoma presenting as a "hot spot" on Tc-99m phytate SPECT imaging.

The cases of two patients with surgically proven splenic hamartomas with "hot spots" on Tc-99m phytate SPECT imaging are presented. There was intense radiocolloid accumulation in the peripheral portion of a large single tumor in one patient, and in each of three isolated tumors in the other patient. The intense uptake might be related to the function of proliferated reticuloendothelial cells in the tumors. These unique findings were not clearly identified on the planar images.

Preliminary application of dynamic pulmonary xenon-133 single-photon emission tomography in the evaluation of patients with pulmonary emphysema for thoracoscopic lung volume reduction surgery.

Dynamic pulmonary xenon-133 single-photon emission tomography (SPET) with three-dimensional (3D) displays was preliminarily applied to select resection targets for thoracoscopic lung volume reduction surgery (LVRS) and to assess regional ventilatory changes following surgery. Dynamic SPET was performed using a triple-detector SPET system in 14 patients with pulmonary emphysema before and after LVRS. After reconstructing colour-illuminated, surface-rendered 3D images of equilibrium (EQ) and 3-min washout (WO3), a single 3D fusion display was created from these two different time-course image sets, in which the 3D WO3 image indicating 133Xe retention was visible through the overlying 3D EQ image delineating lung contours. Volumetric extent of retention on this display was quantified by a 133Xe retention index, defined as the ratio (%) of total pixel numbers of segmented 3-min WO data to those of EQ data. 133Xe SPET and appropriately thresholded 3D displays efficiently localized a total of 36 retention sites; 19 (52.7%) of these sites were not localized by CT because they were within the widely or homogeneously spreading non-bullous emphysematous lung tissues. The 3D displays enhanced the perception of anatomical configurations and the extent of 133Xe retention compared with multislice tomograms. Postoperatively, 3D fusion display visualized the details of regional changes in retention, and changes in the retention index on the 3D display with a standardized threshold correlated well with changes in 133Xe clearance time (T1/2) and %FEV1 (r = 0.881 and 0. 856, respectively; P<0.0001). This preliminary study indicates that 133Xe SPET and appropriately thresholded, topographic 3D displays are of potential use in selecting resection targets for LVRS, and in evaluating the treatment effects on regional ventilation.

Three-dimensional surface display of dynamic pulmonary xenon-133 SPECT in patients with obstructive lung disease.

UNLABELLED: To better perceive abnormal regional ventilation in patients with obstructive lung disease, a three-dimensional display was applied to dynamic pulmonary 133Xe SPECT. METHODS: Dynamic SPECT was performed using a triple-detector SPECT system in 30 patients with obstructive disease, 13 patients with restrictive disease and 7 normal subjects. After reconstructing color-illuminated, surface-rendered three-dimensional images of equilibrium and 3-min washout (WO3), a single three-dimensional fusion display was created from these two different time-course image sets in which a three-dimensional WO3 image indicating 133Xe retention was transparently visible through three-dimensional equilibrium image delineating lung contours. The three-dimensional equilibrium and WO3 images were created by a 25% threshold of the 133Xe maximal pixel activity (MPA) in equilibrium data. Besides, a three-dimensional WO3 image with a 18% threshold [mean + 2 s.d. ratios (%) of the MPA in WO3 data to that in equilibrium data in normal subjects] was used for assessing the presence of retention compared to normal lungs. RESULTS: The 18% threshold three-dimensional WO3 image showed abnormal retention in obstructive diseases but not in restrictive diseases. The three-dimensional fusion display provided an overview of localized retention in obstructive diseases and enhanced the perception of their spatial relationships and extent compared to those on multislice tomograms. The extent of retention correlated well with %FEV1 (r = 0.813) and 133Xe clearance-time (T(1/2)) (r = 0.912). CONCLUSION: This topographic modality for 133Xe SPECT is helpful for the better perception of anatomic distributions of 133Xe retention and interstudy comparisons of ventilation abnormality in patients with obstructive disease.

201Tl SPECT as an indicator for early prediction of therapeutic effects in patients with non-small cell lung cancer.

This study retrospectively investigated the good parameters on thallium-201 chloride (201Tl) SPECT for early assessment of the therapeutic effects in patients with non-small cell lung cancer. Based on tumor response as determined by chest CT scan about 9 weeks after the end of irradiation with adjuvant chemotherapy, the subjects were divided to the responder group (tumor regression > 50%, n = 13) and non-responder group (tumor regression < 50%, n = 13). 201Tl SPECT was performed before and at the halfway through the course of therapy (average tumor dose, 27.4 Gy +/- 4.5) in all the patients. SPECT was conducted twice 15 min (early scan) and 120 min (delayed scan) after intravenous injection of 148 MBq (4 mCi) of 201Tl. Tumor-to-contralateral normal lung tissue count ratios on both scans were calculated as early and delayed uptake ratios (EUR and DUR), and a retention index (RI) was also derived from these ratios. In the responder group, a significant decrease in DUR and RI halfway through the therapy was observed compared to pretreatment (2.6 +/- 0.6 vs. 3.5 +/- 1.0; p < 0.01, and -2.3% +/- 25.5 vs. 37.4% +/- 17.8; p < 0.001, respectively), even though EUR did not change significantly (N.S.). By contrast, in the non-responder group, there were no significant changes in any of these parameters (N.S.). When comparing DUR and RI for the two groups halfway through the therapy, DUR and RI were significantly lower in the responder group (both; p < 0.01), but no significant difference was noted in EUR (N.S.), and the percent reduction in tumor size did not correlate with the percent decrease in DUR or RI (N.S.). These results indicate that the extent of decrease in DUR and RI after therapy can be a useful parameter for early assessment of the therapeutic effects in patients with non-small cell lung cancer.

Evaluation of abnormal regional ventilation in patients with lung cancer using three-dimensional display of dynamic 133Xe SPET.

Preliminary studies were carried out of regional ventilation in lung cancer using three-dimensional (3D) display of dynamic pulmonary 133Xe single photon emission tomography (SPET). Transaxial equilibrium and washout images were obtained from SPET data acquired with an acquisition time of 30 s using a triple-detector SPET system in 39 patients with lung cancer. After reconstructing colour-illuminated, surface-rendered 3D images of equilibrium and 3-min washout (WO3), a single 3D fusion display was created from these two different time-course image sets, in which the 3D WO3 image indicating 133Xe retention was visible through the 3D equilibrium image delineating lung contours. The extent of retention was assessed using the 133Xe retention index, defined as the ratio of summed pixels of the segmented WO3 data to those of the segmented equilibrium data. 133Xe SPET was highly sensitive and specific for the presence of regional ventilation abnormalities associated with endobronchial tumour or bronchial compression due to enlarged lymph nodes. These abnormalities were demonstrated irrespective of the presence or absence of secondary changes distal to the tumour on the chest computed tomography scan. The geometrically realistic 3D fusion display enhanced anatomic localization of the regional ventilation abnormalities compared to the information from multislice tomograms, and the 133Xe retention index correlated well with %FEV1 (r = 0.828). This topographic 3D display for 133Xe SPET allows better perception of anatomic localization and extent of 133Xe retention. It will be useful for assessing regional ventilatory function in patients with lung cancer.

Characterization of hepatic adenoma with atypical appearance on CT and MRI by radionuclide imaging.

The appearance of hepatic adenomas on CT and MRI are highly variable because of their varied histopathology, and images of adenomas are at times indistinguishable from those of other hepatic tumors. The authors present two patients with hepatic adenomas with extremely atypical CT and MRI manifestations demonstrating a "nodule-in-nodule" appearance. Radionuclide imaging in both patients showed decreased Ga-67 uptake in the adenomas compared to normal liver, negative colloid (Tc-99m phytate) uptake in the adenomas, and early uptake and subsequent retention of Tc-99m PMT. This correctly characterized the unique histopathologic features of the resected tumors. Radionuclide imaging using a combination of radiotracers may play an important role in aiding the diagnosis of this rare benign tumor, despite variable CT and MRI appearances.

Radionuclide imaging in emphysema after lung volume reduction surgery.

Three dimensional (3D) surface displays of dynamic Xe-133 and Tc-99m MAA SPECT were performed to evaluate regional lung function in two patients with pulmonary emphysema before and after thoracoscopic lung volume reduction surgery. The 3D displays were reconstructed using a color-illuminated, surface-rendering technique. For the Xe-133 studies, a fusion display of 3D equilibrium (EQ) and 3-minute washout (WO) images was used to show the distribution of Xe-133 retention, which were transparently seen within the entire lung contours delineated by the EQ image. In both patients, these 3D displays allowed an overview of the localized poorly functioning lungs with Xe-133 retention or reduced perfusion with geometric realism. The location and extent were more easily comprehended on the displays compared to the slice-by-slice presentations of tomograms. Postoperatively, the displays efficiently revealed restored function in the remaining lungs. The 3D surface displays of the two SPECT procedures providing topographic information of regional lung function appears to contribute to the treatment strategy of this surgery.

Three-dimensional surface displays of perfusion SPET in the evaluation of patients with pulmonary emphysema for thoracoscopic lung volume reduction surgery.

A modified, three-dimensional display was applied to 99Tcm-macroaggregated albumin (99Tcm-MAA) SPET to help assess the effect of thoracoscopic lung volume reduction surgery (LVRS) on regional lung perfusion. Surface-rendered three-dimensional images for 99Tcm-MAA and xenon-133 (133Xe) equilibrium (EQ) SPET were obtained in 11 patients with pulmonary emphysema before and after LVRS. A single three-dimensional fusion display of both images was then reconstructed, and the perfused lungs were transparently visible through the lung contours delineated by the three-dimensional 133Xe EQ image. The extent of preserved perfusion in the lung (the perfusion index) was estimated using the ratio (%) of the total pixel numbers of the segmented perfusion data to those of the 133Xe lung volume data. The three-dimensional fusion display provided an overview of the distribution of hypoperfusion in the lungs with geometric realism and enhanced the perception of anatomic size and configuration compared with multiple tomograms and three-dimensional perfusion images without superimposition of three-dimensional 133Xe image. Post-operatively, it displayed restored perfusion in the remaining lungs, and changes in the perfusion index correlated with %FEV1 (r = 0.731, P = 0.0001) more closely than the perfusion data alone (r = 0.593, P < 0.01). This method is useful for directing LVRS and assessing its effectiveness, as it provides precise tomographic information on regional perfusion.

Radionuclide angiography and ventilation/perfusion studies in two patients with systemic arterial supply to the basal segment of the left lung.

The findings of radionuclide studies in two adult men with systemic arterial supply to the basal segment of the left lung without sequestration are reported. Radionuclide angiography with Tc-99m human serum albumin-diethylenetriamine showed that the lung was perfused by the systemic circulation rather than by the pulmonary artery. Ventilation and perfusion scans with Xe-133 and Tc-99m MAA showed a V/Q mismatch in this area, suggesting the presence of normal bronchial communication without a pulmonary arterial supply. These results also suggest the presence of a left-to-left shunt in the well-ventilated lung in this area. MRI and conventional angiography showed an aberrant artery arising from the descending thoracic aorta, supplying the basal segment of the left lung without a pulmonary artery. In both patients, left lower lobectomy showed normal alveobronchial structures without sequestration. Radionuclide angiography and ventilation/perfusion imaging appear to be reliable noninvasive methods for diagnosing this rare anomaly with a left-to-left shunt.

Ventilation abnormalities in obstructive airways disorder: detection with pulmonary dynamic densitometry by means of spiral CT versus dynamic Xe-133 SPECT.

PURPOSE: To evaluate pulmonary dynamic densitometry (PDD) by means of spiral computed tomography (CT) for detection of ventilation abnormalities in obstructive airways disorders compared with dynamic xenon-133 single photon emission CT. MATERIALS AND METHODS: Eight-second spiral CT was performed during two to three respiratory cycles in six healthy volunteers, 19 patients with airways disorder, and six patients with restrictive lung disease. The data sets were reconstructed as 36 1-second temporally overlapping images at 0.2-second intervals, and regional PDD curves were displayed. Regional ventilation was assessed by means of Xe-133 clearance time. RESULTS: Normal lungs showed smooth, sinusoidal PDD curves with maximal amplitude in lung attenuation change (MALAC) of 54.9 HU +/- 24.5, whereas lungs with obstructive airways disorders with prolonged Xe-133 clearance showed significantly diminished MALAC (31.6 HU +/- 20.1, P < .0001), accompanied by irregularity, asynchronous phase, and deterioration of normal ventral-to-dorsal gradients in MALAC and lung attenuation. Lungs with restrictive diseases without prolonged Xe-133 clearance did not show statistically significant reduction in MALAC. In a total of 251 lung regions, regional MALAC correlated inversely with Xe-133 clearance time (r = -.842). CONCLUSION: PDD by means of spiral CT is acceptable for the detection of ventilation abnormalities in obstructive airways disorder.

[Usefulness of 3-D dynamic pulmonary xenon-133 SPECT for thoracoscopic lung volume reduction surgery in patients with pulmonary emphysema].

Six patients with pulmonary emphysema scheduled to undergo thoracoscopic lung volume reduction surgery (TLVRS) were evaluated by three-dimensional (3-D) dynamic pulmonary xenon-133 SPECT. Serial 30-second dynamic SPECT data for equilibrium and washout (for 5 min) were acquired using a continuous repetitive rotating acquisition mode with a triple-detector SPECT system. SPECT data were reconstructed to 3-D images with a color, surface-rendering technique, and a 3-D fusion image of the 3-min washout image over the equilibrium image was obtained. Regional ventilation was visually assessed on the fusion 3-D images and quantified by xenon-133 half-washout time (T1/2) and mean transit time (MTT). The 3-D fusion image localized and lateralized the worst diseased sites with xenon-133 retention. Xenon-133 retention, T1/2 and MTT were reduced on these images in five patients with improved pulmonary function tests following TLVRS. However, xenon-133 retention was greater in one with asynchronous diaphragm movement after TLVRS. This modality will assist TLVRS in determining the lung resection target and in evaluating the treatment effect.

SPECT with In-111 autologous platelets to detect residual splenic tissue in two patients with relapsed thrombocytopenia.

In two patients with relapsed thrombocytopenia, the authors used SPECT with In-111 labeled autologous platelets to identify residual splenic tissue after splenectomy. One case involved a previously splenectomized patient with idiopathic portal hypertension, while the other had relapsed chronic idiopathic thrombocytopenic purpura (ITP). In both patients, SPECT showed a higher In-111 uptake in the splenic tissues compared with planar images. In the patient with ITP, a small accessory spleen had been overlooked on abdominal CT because of post-operative changes, but it was identified by superimposition of SPECT/CT images. These cases indicate that In-111 platelet SPECT is useful in detecting and localizing residual accessory splenic tissue associated with relapsed thrombocytopenia.

[A case of bilateral adrenal neuroblastomas detected by bone scintigraphy].

A 7-month-old girl, who had been resected the left adrenal neuroblastoma 20 days ago, underwent bone scintigraphy with 90mTc-HMDP to survey bone metastases. The bone scan demonstrated avid uptake in the right adrenal gland, in which 123I-MIBG also accumulated. However, the degree of 123-I-MIBG uptake in the right adrenal gland was not necessary higher compared to that in the normal adrenal glands in 7 patients after resection of hemilateral neuroblastomas. Reviewing the preoperative abdominal CT, a swelling of the right adrenal gland had been overlooked because of the small size of 10 x 12 mm in diameter. The follow-up CT after surgery revealed a more growth of the right adrenal gland, accompanied by reelevation of urine vanilmandelic acid. This patient was thus diagnosed as bilateral neuroblastomas. Because bone scintigraphy frequently shows abnormal uptake in primary neuroblastomas, it has potentially diagnostic value for early detection of bilateral adrenal neuroblastomas.

Superimposition of In-111 platelet SPECT and CT/MR imaging in intracardiac thrombus.

An initial attempt to superimpose in-111-labeled platelet SPECT over CT/MRI in two patients with intracardiac thrombus is presented. One patient was a 65-year-old woman with a history of mitral and tricuspid valve replacement. This patient had a large thrombus measuring 74 x 43 x 34 mm in the right atrium. Fusion imaging with CT showed increased in-111 activity on the surface of the thrombus, which was visualized as circular activity on a planar image. The other patient was a 72-year-old woman who had a thrombus measuring 17 x 14 x 12 mm at the cardiac apex. Planar imaging showed two discrete areas of abnormal in-111 activity. Superimposition of the SPECT image over MR revealed that one of these areas corresponded to the small thrombus, whereas the other related to a previous subendomyocardial biopsy. In both patients, the activity ratio of the abnormal in-111 accumulation versus the cardiac chamber on SPECT was greater than that on planar images. The correlation of in-111 platelet SPECT and CT/MRI was useful in accurately localizing the intracardiac thrombus.

Iodine-123-MIBG imaging in pheochromocytoma with cardiomyopathy and pulmonary edema.

We encountered a patient with pheochromocytoma associated with a catecholamine-induced cardiomyopathy that developed recurrently bilateral and unilateral pulmonary edema. The diagnosis of pheochromocytoma was made by elevated plasma catecholamine levels and the intense tumor [123I]MIBG uptake and was confirmed at the time of surgery. The patient showed reduced myocardial [123I]MIBG uptake with left ventricular dysfunction, and endomyocardial biopsy findings were consistent with the diagnosis of catecholamine-induced cardiomyopathy. After tumor resection, plasma levels of catecholamine were normalized, and pulmonary edema never recurred, although cardiac dysfunction did not show an improvement on echocardiography. Myocardial and lung [123I]MIBG uptake increased when compared to uptake levels on preoperative scans, but myocardial uptake was still below normal. These findings indicated that over-secreted catecholamines influenced both the heart and lungs. Pheochromocytoma can induce cardiac and lung injuries, and [123I]MIBG scanning may contribute not only to tumor characterization but also to assessing and monitoring the influence of catecholamines on the heart and lungs.

Dynamic pulmonary SPECT of xenon-133 gas washout.

UNLABELLED: A triple-detector SPECT data acquisition mode of "continuous repetitive rotation acquisition" was applied to dynamic pulmonary SPECT with 133Xe gas. METHODS: Subjects included 7 healthy volunteers, 22 patients with a space-occupying mass lesion, 22 with obstructive lung disease and 10 with restrictive lung disease. Following rebreathing of 133Xe, equilibrium and washout SPECT images during spontaneous breathing were acquired every 30 sec for 5-7 min. Regional 133Xe washout was assessed by the real half-time (T1/2) and mean transit time (MTT) images. RESULTS: SPECT and MTT images represented a gravity-induced gradient of ventilation in normal lungs and detailed the distribution of heterogeneous 133Xe washout in patient's lungs with or without abnormalities on chest x-ray CT. The T1/2 (111.4 +/- 26.4 sec) and its coefficient of variation (0.36 +/- 0.13) in obstructive lung diseases were significantly different from those (56.8 +/- 3.9 sec and 0.16 +/- 0.15) in restrictive lung diseases (p < 0.001, p < 0.05, respectively). Comparison of SPECT and planar studies assessed in 19 patients revealed superiority of SPECT in detecting ventilatory abnormalities and a high correlation of T1/2 between the two studies ( r= 0.977, p < 0.001). CONCLUSION: This modality has excellent potential for elucidating the distribution and nature of ventilatory abnormalities.

Relationship between thallium-201 uptake and tumour proliferative ability in thyroid nodules.

To evaluate whether thallium-201 scan can reflect tumour proliferative activity in thyroid nodules. We compared the degree of 201Tl uptake with the tumour proliferative ability as assessed immunohistochmically by the labelling index of proliferating cell nuclear antigen (PCNA) in malignant and benign thyroid nodules. The case material comprised ten benign and 31 malignant surgically resected nodules from a total of 41 patients. 201Tl scan was performed 5 min (early scan) and 2h (delayed scan) after intravenous injection of 74 MBq of 201Tl. The degree of 201Tl uptake was visually divided into three grades [from (-) to (++)], as compared with its uptake in normal adjacent thyroid tissue. Immunohistochemical staining of PCNA was performed using a monoclonal antibody for PC10 on paraffin-embedded specimens. On both the early and the delayed scans, the mean PCNA index in the nodules with an intense 201Tl, i.e. (++), was significantly higher than that in nodules with a lower or with negative 201Tl uptake. The correlation was higher on the delayed 201Tl scan (P=0.009) than on the early scan (P=0.019). Our results indicate that 201Tl uptake may reflect the tumour proliferative activity of thyroid nodules, and this is especially true with regard to the uptake on delayed scans.