Comparative study between endoscopic ultrasonography and positron emission tomography-computed tomography in staging patients with esophageal squamous cell carcinoma.

Treatment strategy of esophageal cancer mainly depends on accurate staging. At present, no single ideal staging modality is superior to another in preoperative tumor-node-metastasis (TNM) staging of patients with esophageal cancer. We aimed to investigate the efficacy of endoscopic ultrasonography (EUS) and positron emission tomography-computed tomography (PET-CT) for staging of esophageal cancer. We retrospectively studied 118 consecutive patients with esophageal squamous cell carcinoma who underwent esophagectomy with or without neoadjuvant chemoradiotherapy (CRT) over a near 3-year period between January 2005 and November 2008 at a tertiary hospital in Taiwan. Patients were separated into two groups: without neoadjuvant CRT (group 1, n= 28) and with CRT (group 2, n= 90). Medical records of demographic data and reports of EUS and PET-CT of patients before surgery were reviewed. A database of clinical staging by EUS and PET-CT was compared with one of pathological staging. The accuracies of T staging by EUS in groups 1 and 2 were 85.2% and 34.9%. The accuracies of N staging by EUS in groups 1 and 2 were 55.6% and 39.8%. The accuracies of T and N staging by means of PET-CT scan were 100% and 54.5% in group 1, and were 69.4% and 86.1% in group 2, respectively. In group 2, 38 of 90 patients (42.2%) achieved pathologic complete remission. Among them, two of 34 (5.9%) and 12 of 17 (70.6%) patients were identified as tumor-free by post-CRT EUS and PET-CT, respectively. EUS is useful for initial staging of esophageal cancer. PET-CT is a more reliable modality for monitoring treatment response and restaging. Furthermore, the accuracy of PET-CT with regard to N staging is higher in patients who have undergone CRT than those who have not.

Role of ultrasound-guided fine needle aspiration in assessing the impalpable cervical node with increased 18F-fluorodeoxyglucose uptake on positron emission tomography scanning: preliminary communication.

OBJECTIVES: 18F-Fluorodeoxyglucose positron emission tomography can detect cervical metastases before they are palpable. However, false positive results are not uncommon. This paper reports the use of ultrasound-guided fine needle aspiration to determine the nature of impalpable cervical nodes that are positive on positron emission tomography scanning. METHODS: Ultrasound-guided fine needle aspiration was performed in 10 cancer patients with suspicious cervical nodes revealed by positron emission tomography scan. Clinical data were retrospectively reviewed. RESULTS: The underlying cancers included lung cancer (three patients), nasopharyngeal carcinoma (two), oesophageal cancer (two), buccal cancer (one), bladder cancer (one) and Langerhan's histiocytosis (one). The lymph nodes were located in the supraclavicular region in four patients, the level II region in four, the level IV region in one and the accessory chain in one. Cytological examination was positive for malignant cells in eight patients, all of whom received salvage treatment. Two of these patients died of distant metastases. Cytological examination revealed a benign or reactive lesion in two patients, who at the time of writing were alive and well, 19 and 36 months after examination. CONCLUSIONS: Ultrasound-guided fine needle aspiration is a minimally invasive procedure which enables cytological examination of suspicious cervical lymph nodes detected by positron emission tomography scanning, allowing further treatment to be planned.

Whole-body F-18 FDG PET for hepatocellular carcinoma patients after interventional treatment.

For hepatocellular carcinoma (HCC) patients after primary treatment, conventional anatomical imagings may not be reliable in detecting residual, recurrent or metastatic lesions. The aim of this retrospective study was to evaluate the usability of FDG PET in the follow-up of HCC patients after prior interventional treatments. The database consisted of 10 male and 2 female (age range, 46-82 years; mean age, 63.4 +/- 11.7 years) who had received primary HCC treatments and underwent FDG PET scans at the National Taiwan University Hospital. The accuracy of FDG PET detection was determined by the histopathological results or other clinical evidences afterwards. Of the 22 lesions, FDG PET studies were able to detect 8 (8/10, 80%) intrahepatic lesions and 8 (8/12, 66.7%) extrahepatic lesions. The lesion based detection rate of FDG PET is 72.7% (16/22). FDG PET was able to detect at least 1 lesion in 11 patients. The 6 false negative lesions in 6 patients include 2 intrahepatic lesions, 1 brain lesion, 1 sphenoid sinus lesion and 2 multiple subcentimeter pulmonary lesions. FDG PET scan is able to provide valuable auxiliary information for the follow up of HCC patients clinically suspicious of recurrence if their conventional image findings are not unambiguous.

Different fibrovascularization rate between coralline hydroxyapatite and high density porous polyethylene (Medpore) measured by 99mTc-MDP bone scintigraphy 6 months after intraorbital implantation.

Many materials and types of implant have been used to achieve a cosmetic effect and prosthesis motility in the anophthalmic socket. Hydroxyapatite remains the implant material of choice for producing the most natural prosthesis motility while porous polyethylene shows promising characteristics as another useful material. The aim of this study was to compare the fibrovascular ingrowth rates of orbital implants between coralline hydroxyapatite and high density porous polyethylene (Medpore). The fibrovascularization rate is determined by bone imaging using 99mTc methylene diphosphonate (99mTc-MDP) 6 months after implantation. Our study included 29 patients with coralline, and nine patients with Medpore implants. Our results showed that groups with coralline implants appearing to achieve complete fibrovascularization at a much more rapid rate than those with Medpore. The differences in rate were statistically significant.

Usefulness of Tc-99m ECD brain SPECT to evaluate the effects of methylprednisolone pulse therapy in lupus erythematosus with brain involvement: a preliminary report.

Methylprednisolone pulse therapy (MPT) was introduced to avoid life-threatening complications in systemic lupus erythematosus (SLE) with brain manifestations. However, its efficacy in SLE patients remains uncertain and needs to be objectively evaluated. In this study, technetium-99m ethyl cysteinate dimer (Tc-99m ECD) brain single photon emission computed tomography (SPECT) was used to detect regional cerebral blood flow (rCBF) in SLE patients with normal brain magnetic resonance imaging (MRI) findings. Twelve female SLE patients with neuropsychiatric symptoms were enrolled in this study. All patients had normal brain MRI and abnormal Tc-99m ECD brain SPECT findings. The Tc-99m ECD brain SPECT studies were performed 2 weeks after MPT. Pre- and post-MPT serum levels of anticardiolipin antibodies (ACA) and antiribosomal P antibodies (anti-P) were also measured. Before MPT, four patients had positive ACA and seven had positive anti-P. After MPT, all 12 patients demonstrated negative serologic findings and no neuropsychiatric symptoms. After MPT, ten patients showed complete recovery and two showed partial recovery of rCBF in the follow-up Tc-99m ECD brain SPECT images. This imaging is a logical and objective tool for measuring the effects of MPT in SLE patients with brain involvement by the determination of rCBF changes.

Using 99mTc HMPAO brain SPECT to evaluate the effects of anticoagulant therapy on regional cerebral blood flow in primary antiphospholipid antibody syndrome patients with brain involvement-a preliminary report.

Technetium-99m hexamethylpropylene amine oxime ((99m)Tc HMPAO) brain single photon emission computed tomography (SPECT) was used to evaluate the effects of anticoagulant therapy (ACT) on regional cerebral blood flow (rCBF) in patients with primary antiphospholipid antibody syndrome (PAPS). Sixteen female PAPS patients with neuropsychiatric manifestations and hypoperfusion lesions demonstrated on initial (99m)Tc HMPAO brain SPECT images were enrolled in this study. Follow-up (99m)Tc HMPAO brain SPECT images were performed 1 month after ACT. Meanwhile, serum anticardiolipin antibodies (ACA) were measured before and after ACT. Before ACT, 14 (87.5%) patients had positive ACA. After ACT, all 16 PAPS patients showed decreased serologic findings, and their neuropsychiatric manifestations subsided. After ACT, 11 (68.8%) patients showed complete recovery of regional cerebral blood flow (rCBF) and five (31.2%) patients showed partial recovery in the follow-up (99m)Tc HMPAO brain SPECT images. This type of imaging is a logical and objective tool for measuring the effects of ACT in PAPS patients with brain involvement by determining changes in rCBF.

Abnormal regional cerebral blood flow found by technetium-99m ethyl cysteinate dimer brain single photon emission computed tomography in systemic lupus erythematosus patients with normal brain MRI findings.

In this study, technetium-(99m) ethyl cysteinate dimer ((99m)Tc ECD) brain single photon emission computed tomography (SPECT) was used to detect regional cerebral blood flow (rCBF) of the brain in SLE patients with normal brain magnetic resonance imaging (MRI) findings. Twenty female SLE patients were enrolled in this study, divided into two groups. Group 1 consisted of 10 patients with neuropsychiatric manifestations. Group 2 consisted of 10 patients without neuropsychiatric manifestations. All patients had normal brain MRI findings. Another 10 SLE patients with abnormal MRI findings were included as group 3 for comparison. Meanwhile, 10 healthy female volunteers also underwent brain MRI and (99m)Tc ECD brain SPECT for comparison. The scans revealed hypoperfusion lesions in 9/20 (45%) SLE patients, including 7/10 (70%) cases in group 1 and 2/10 (20%) cases in group 2. In contrast, all 10 patients (100%) in group 3 had abnormal (99m)Tc ECD brain SPECT findings. The parietal lobes were the most commonly involved areas. We conclude that (99m)Tc ECD brain SPECT is more sensitive for detecting rCBF changes than is brain MRI in detecting the brain anatomic changes, and may have a diagnostic value in lupus cerebral involvement. However, (99m)Tc ECD brain SPECT may not be indicated for SLE patients with normal MRI and mild neuropsychiatric symptoms/signs, such headaches and dizziness.

Usefulness of whole body positron emission tomography (PET) with 18F-fluoro-2-deoxyglucose (FDG) to detect recurrent ovarian cancer based on asymptomatically elevated serum levels of tumor marker.

The aim of this study was to evaluate practice usefulness of whole body positron emission tomography (PET) with 18F-fluoro-2-deoxyglucose (FDG) to detect recurrent ovarian cancer based on asymptomatically elevated tumor marker (CA-125) serum levels. Whole-body FDG-PET was performed in 28 patients with suspected recurrent ovarian cancers and asymptomatically increased serum levels of tumor marker (CA-125 antigen) but negative or equivocal other imaging modality results. All of these 28 asymptomatic patients had serum levels of CA-125 antigen >35 U/ml. The final diagnosis of recurrent ovarian cancer was established by operation/biopsy histopathological findings or clinical follow-up longer than 1 year by additional morphologic imaging techniques. Among the 28 patients, the final diagnoses of recurrent ovarian cancers and benign lesions were established in 20 and 8 patients, respectively. FDG-PET accurately diagnosed recurrent ovarian cancers in 19 patients and benign lesions in 7 patients. When asymptomatically elevated serum levels of CA-125 antigen, the diagnostic sensitivity, specificity, and accuracy of FDG-PET to detect recurrent ovarian cancers were 95.0%, 87.5%, and 92.9%, respectively. FDG-PET is a useful technique to detect recurrent ovarian cancers for patients suspected of recurrent ovarian cancers due to asymptomatically elevated serum levels of CA-125 antigen.

Comparing whole body 18F-2-deoxyglucose positron emission tomography and technetium-99m methylene diophosphate bone scan to detect bone metastases in patients with non-small cell lung cancer.

Despite advances in morphological imaging, some patients with non-small cell lung cancer (NSCLC) are found to have non-resectable disease at surgery or die of recurrence within a year of surgery. At present, metastatic bone involvement is usually assessed using conventional technetium-99m methylene diophosphate (Tc-99m MDP) whole body bone scan (bone scan), which has a high sensitivity but a poor specificity. We have attempted to evaluate the usefulness of whole body positron emission tomography with 18F-2-deoxyglucose (FDG-PET) for the detection of malignant bone metastases of NSCLC, and to compare FDG-PET results with Bone Scan findings. Forty-eight patients with biopsy-proven NSCLC and suspected to have stage IV disease underwent whole body bone scan and FDG-PET to detect bone metastases. The final diagnoses of bone metastases were established by operative, histopathological findings or clinical follow-up longer than 1 year by additional radiographs or following FDG-PET/Tc-99m MDP bone scan findings showing progressively and extensively widespread bone lesions. A total of 138 bone lesions found on either FDG-PET or Tc-99m MDP bone scan were evaluated. Among the 106 metastatic and 32 benign bone lesions, FDG-PET and Tc-99m MDP bone scan could accurately diagnose 99 and 98, as well as 30 and 2 metastatic and benign bone lesions, respectively. Diagnostic sensitivity and accuracy of FDG-PET and Tc-99m MDP bone scan were 93.4% and 92.5%, as well as 93.5% and 72.5%, respectively. In conclusion, our data suggest that FDG-PET with the same sensitivity and a better accuracy than those of Tc-99m MDP bone scan to detect metastatic bone lesions in patients with biopsy-proven NSCLC and suspected to have stage IV disease.

Comparing whole body 18F-2-deoxyglucose positron emission tomography and technetium-99m methylene diphosphate bone scan to detect bone metastases in patients with renal cell carcinomas - a preliminary report.

PURPOSE: Conventional technetium-99m methylene diphosphate whole body bone scan (bone scan) has a high sensitivity but a poor specificity to detect bone metastases. However, positron emission tomography with 18F-2-deoxyglucose (FDG-PET) can offer superior spatial resolution and improved specificity. We have attempted to evaluate the usefulness of FDG-PET for detecting bone metastases in renal cell carcinomas (RCC) and to compare FDG-PET results with bone scan findings. METHODS: Eighteen patients were selected for this study with biopsy-proven RCC. They were suspected of having bone metastases and were undergoing bone scan and FDG-PET to detect bone metastases. The final diagnoses of bone metastases were established by operative, histopathological findings or clinical follow-up longer than 1 year by additional radiographs or following FDG-PET/bone scan findings showing progressive and extensive widespread bone lesions. RESULTS: A total of 52 bone lesions including 40 metastatic and 12 benign bone lesions found on either FDG-PET or bone scan were evaluated. FDG-PET could accurately diagnose all 40 metastatic and 12 benign bone lesions. Bone scan could accurately diagnose only 31 metastatic bone lesions. Diagnostic sensitivity and accuracy of FDG-PET were 100% and 100%, respectively,and bone scan were 77.5% and 59.6%, respectively. CONCLUSIONS: Our data suggest that FDG-PET has a higher sensitivity and a better accuracy than that of bone scan to detect bone metastases in patients with RCC.

Value of whole body 18F-fluoro-2-deoxyglucose positron emission tomography in the evaluation of recurrent cervical cancer.

To evaluate the clinical value of whole body positron emission tomography (PET) with 18F-fluoro-2-deoxyglucose (FDG) in recurrent cervical cancer, the records of 20 patients who underwent FDG-PET scans were reviewed to detect local recurrence, pelvic/para-aortic lymph node metastases and distal metastases. The final diagnosis was based on operative, histopathological findings or clinical follow-up for longer than one year. FDG-PET accurately detected 18 patients with recurrent diseases (12 patients with local recurrences, 16 patients with pelvic lymph node metastases, 14 patients with para-aortic lymph node metastases and 4 patients with distal metastases of other sites). However, 2 patients with local recurrences had false- negative FDG-PET results as well as 1 patient without local recurrence and 1 patient without pelvic lymph node metastases who had false-positive FDG-PET results. The overall sensitivity and specificity of FDG-PET for patients were 90% and 100%, for local recurrence were 86% and 92%, for pelvic lymph node metastases were 100% and 94%, for para-aortic lymph node metastases were 100% and 100% and for distal metastases were 100% and 100%, respectively. In conclusion, whole body FDG-PET is a useful diagnostic tool in the evaluation of recurrent cervical cancer. It appears to be promising for detecting recurrent cervical cancer, lymph node metastases and distal metastases.

Metabolic changes following subthalamotomy for advanced Parkinson's disease.

We studied 6 advanced-stage Parkinson's disease patients with [18F] fluorodeoxyglucose/positron emission tomography before and 3 months after unilateral ablation of the subthalamic nucleus performed with microelectrode mapping. Operative changes in glucose metabolism were assessed by comparing baseline and postoperative scans. We also quantified operative changes in the activity of an abnormal Parkinson's disease-related metabolic network that we had identified in previous [18F] fluorodeoxyglucose/positron emission tomography studies. Following unilateral subthalamic nucleus ablation, a highly significant reduction in glucose utilization was present in the midbrain ipsilateral to the lesion site, most pronounced in the vicinity of the substantia nigra pars reticularis. Significant metabolic reductions were also present in the ipsilateral internal globus pallidus, ventral thalamus, and pons. Operative changes in Parkinson's disease network activity differed significantly for the lesioned and unlesioned hemispheres. In the lesioned hemisphere, network activity declined significantly following surgery, but was unaltered in the contralateral, unlesioned hemisphere. These results suggest that subthalamotomy reduces basal ganglia output through internal globus pallidus/substantia nigra pars reticularis and also influences downstream neural activity in the pons and ventral thalamus. This procedure also reduces the activity of abnormal Parkinson's disease-related metabolic brain networks, suggesting a widespread modulation of motor circuitry.

Inhomogeneity of myocardial perfusion in heart transplant recipients: evaluation with dobutamine thallium-201 SPECT.

Progressive heterogeneity of thallium-201 single photon emission computed tomography (Tl-201 SPECT) in heart transplant recipients has been documented in Caucasians. However, in Chinese heart transplant recipients, a lower incidence of transplant coronary artery disease (CAD) has been noted than in Western transplant recipients. In this study, we examine whether heterogeneity of Tl-201 SPECT exists in Chinese transplant recipients. Dobutamine Tl-201 SPECT was performed in 40 heart transplant recipients and the inhomogeneity scores were calculated. The difference between the scores of transplant recipients surviving less than 12 months and those of control subjects were not statistically significant. One year after transplantation, the inhomogeneity score increased progressively. The scores of transplant patients in the second and third years after transplant were similar to those of single-vessel CAD patients. Three years after transplant the scores were greatly increased. Thus, our data suggest that the progressive nature of graft vasculopathy also exists in Chinese heart transplant recipients. The progressive Tl-201 abnormalities may be one of the early signs of graft vasculopathy.

Comparing 18-fluoro-2-deoxyglucose positron emission tomography with a combination of technetium 99m tetrofosmin single photon emission computed tomography and computed tomography to detect recurrent or persistent nasopharyngeal carcinomas after radiotherapy.

BACKGROUND: The diagnostic accuracy of combined computed tomography (CT) and technetium 99m tetrofosmin (Tc-TF) single photon emission computed tomography (SPECT) of head and neck to differentiate recurrent or residual nasopharyngeal carcinomas (NPCs) from benign lesions after radiotherapy was evaluated and compared with positron emission tomography (PET) with 18-fluoro-2-deoxyglucose (FDG). METHODS: Four months after radiotherapy, 36 patients with NPC underwent Tc-TF SPECT and CT of head and neck to differentiate recurrent or residual NPC from benign lesions. Histopathologic examinations were performed on nasopharyngeal biopsies of all 36 patients. RESULTS: Based on the biopsy results, the sensitivity, specificity, and accuracy of Tc-TF SPECT were 64%, 96%, and 86%, respectively, for differentiation of recurrent or persistent NPC from benign lesions. For CT and FDG-PET, the sensitivity, specificity, and accuracy were 73%, 88%, and 83% and 100%, 96%, 97%, respectively. For the 27 patients with NPC whose Tc-TF SPECT and CT results were congruent, the combination of Tc-TF SPECT and CT had the same sensitivity, specificity, and accuracy (100%, 96%, and 96%) as FDG-PET. For the nine patients with NPC with incongruent Tc-TF SPECT and CT results, FDG-PET correctly differentiated two benign lesions from seven recurrent/residual NPCs. CONCLUSIONS: Although, FDG-PET is the best tool for detecting recurrent or residual NPC, combined congruent Tc-TF SPECT and CT results achieved the same accuracy as FDG-PET. Therefore, we concluded that FDG-PET could be considered only when Tc-TF SPECT and CT give incongruent results.

Accuracy of biphasic response, sustained improvement and worsening during dobutamine echocardiography in predicting recovery of resting myocardial dysfunction after revascularization: comparison with thallium-201 SPECT.

To evaluate the accuracy of various types of wall motion response during dobutamine echocardiography (DE) in predicting functional recovery after revascularization, we studied 30 patients with stable coronary disease and left ventricular dysfunction by simultaneous DE and (201)Tl reinjection SPECT. Among 480 segments (16 segments/patient), 199 had abnormal wall motion at baseline and 167 were revascularized. The predictive value for recovery of function was 72% for a biphasic response, 61% for sustained improvement, 77% for worsening, and 27% for no change (p < 0.01 vs. each). Biphasic response had a sensitivity of 40% and specificity of 85%. Combining biphasic, sustained improvement and worsening responses, the sensitivity, specificity and accuracy were 76%, 65% and 71%, respectively. For (201)Tl SPECT, they were 90%, 65% and 78%, respectively. Thus, a biphasic response alone is of low sensitivity. Combination of biphasic, sustained improvement and worsening responses gives an accuracy rate comparable to that of (201)Tl reinjection SPECT in assessing functional recovery.

Comparison of ischemic patterns in myocardial bridge and syndrome X: evaluation by dobutamine stress echocardiography and stress thallium-201 SPECT.

BACKGROUND AND PURPOSE: Ischemic patterns in patients with syndrome X are thought to differ from those in patients with myocardial bridge, because the mechanisms of coronary flow reduction in these two diseases are different. The aim of this study was to compare the ischemic patterns in patients with syndrome X and those with myocardial bridge through the use of dobutamine stress echocardiography (DSE) and stress thallium-201 single-photon emission computed tomography (SPECT). METHODS: Twenty-six patients with typical angina and stress-induced ST-segment depression were enrolled. All patients underwent coronary angiography, DSE, and stress thallium-201 SPECT within 7 days after enrollment. RESULTS: Of the 26 patients enrolled, 10 had myocardial bridge of the left anterior descending artery and 16 had syndrome X. Among patients with myocardial bridge, myocardial dyssynergy was found by DSE in five patients and reversible or fixed thallium-201 perfusion defects were found in four. Seven patients with myocardial bridge had reverse redistribution patterns on thallium-201 scintigraphy. In the 16 patients with syndrome X, myocardial dyssynergy was found by DSE in only one patient (p = 0.018 vs myocardial bridge group) and reversible or fixed thallium-201 perfusion defects were found in nine (p > 0.05 vs myocardial bridge group). Four patients with syndrome X had reverse redistribution patterns on thallium-201 scintigraphy. The resting left ventricular end-diastolic pressure was higher in patients with myocardial bridge than in those with syndrome X (17 +/- 4 vs 12 +/- 5 mm Hg, p = 0.02). CONCLUSIONS: The most common ischemic patterns in patients with syndrome X were chest pain and stress-induced ST-segment depression, followed by myocardial perfusion defects. Dobutamine-induced dyssynergy was rare. Left ventricular end-diastolic pressure elevation and dobutamine-induced wall motion abnormalities were more common in patients with myocardial bridge than in those with syndrome X.

Differentiation of radiographically indeterminate solitary pulmonary nodules with.

BACKGROUND: The purpose of this preliminary study was to evaluate the efficacy of positron emission tomography (PET) with [18F]fluoro-2-deoxyglucose (FDG) for differentiating benign from malignant solitary pulmonary nodules. METHODS: Twenty-six patients (12 females, 14 males, age 27-79 years) with radiographically indeterminate solitary pulmonary nodules underwent FDG-PET and the findings were compared with the results of pathological examination of biopsy samples. FDG activity in the lesion was expressed as the ratio of lesion-to-background counts (L/B ratio) for semiquantitative analysis. RESULTS: The mean L/B ratio of malignant lesions (8.81+/-3.71, n = 20) was not significantly higher than that of benign lesions (4.71+/-3.00, n = 6) (p = 1.00). Using a cut-off L/B ratio of 5.0 for malignancy, FDG-PET correctly detected 19 true positive and three true negative cases, but failed to detect three false positive (two abscesses and one cryptococcus) cases and one false negative (adenocarcinoma) case. The sensitivity, specificity, accuracy, positive predictive value and negative predictive value were 95, 50, 86, 75 and 85%, respectively. CONCLUSIONS: FDG-PET is a sensitive modality for detecting malignancy, but is not specific enough. Benign lung lesion with active inflammation could demonstrate high FDG uptake, making it difficult to differentiate from malignancy. In the future, we will increase the case numbers to evaluate further the utility of FDG-PET for differentiating radiographically indeterminate solitary pulmonary nodules.

Assessment of the myocardial changes in heart transplant recipients without evident acute myocardial rejection by integrated backscatter: comparison with simultaneous dobutamine stress echocardiography and (201)thallium spect.

Cardiomyocyte hypertrophy and interstitial fibrin deposition develop in cardiac allografts and contribute to the functional changes of transplanted hearts. We hypothesized that integrated backscatter (IBS) can detect these myocardial changes. A total of 32 heart transplant recipients with either no or mild acute rejection (International Society of Heart and Lung Transplantation grade IA) were enrolled in this study. IBS data of myocardium were collected immediately before simultaneous dobutamine stress echocardiography (DSE) and (201)thallium imaging. Coronary angiography and endomyocardial biopsy were also performed. Coronary angiography showed diffuse narrowing in 1 patient who also had abnormal results of IBS, DSE, and thallium results. In the other 31 patients with patent coronary arteries, there were 3 patients (10%) with abnormal DSE results, 19 patients (61%) with abnormal IBS patterns, and 16 patients (52%) with reversible thallium perfusion defects. Of the patients, 44% had cardiomyocyte hypertrophy and 56% interstitial fibrin deposition. There were significant differences in the prevalence of (201)thallium perfusion defects and serum cyclosporine levels between patients with and without abnormal IBS patterns. Pathologic changes were also associated with abnormal IBS patterns (p = 0.01). However, there was no association between abnormal IBS and DSE results. By multiple logistic regression analysis, the abnormal IBS patterns were associated inversely with serum cyclosporine level (p = 0.028). In conclusion, abnormal IBS patterns are associated significantly with perfusion heterogeneity and pathologic changes in heart transplant recipients without evident acute myocardial rejection. There is no association between abnormal IBS patterns and dobutamine-induced dyssynergy in these patients. IBS provides a noninvasive approach for detection of myocardial changes in transplanted hearts without evident acute rejection.