Creation and characterization of normal myocardial perfusion imaging databases using the IQ·SPECT system.

BACKGROUND: Image acquisition by short-time single-photon emission-computed tomography (SPECT) has been made feasible by IQ·SPECT. The aim of this study was to generate normal databases (NDBs) of thallium-201 (201Tl) myocardial perfusion imaging for IQ·SPECT, and characterize myocardial perfusion distribution. METHODS AND RESULTS: We retrospectively enrolled 159 patients with a low likelihood of cardiac diseases from four hospitals in Japan. All patients underwent short-time 201Tl myocardial perfusion IQ·SPECT with or without attenuation and scatter correction (ACSC) in either supine or prone position. The mean myocardial counts were calculated using 17-segment polar maps. Three NDBs were derived from supine and prone images as well as supine images with ACSC. Differences between the supine and prone positions were observed in the uncorrected sex-segregated NDBs in the mid-inferolateral counts (p ≤ 0.016 for males and p ≤ 0.002 for females). Differences between IQ·SPECT and conventional SPECT were also observed in the mid-anterior, inferolateral, and apical lateral counts (p ≤ 0.009 for males and p ≤ 0.003 for females). Apical low counts attributed to myocardial thinning were observed in the apical anterior and apex segments in the supine IQ·SPECT NDB with ACSC. CONCLUSIONS: There were significant differences between uncorrected supine and prone NDBs, between uncorrected supine NDB and supine NDB with ACSC, and between uncorrected supine NDB and conventional SPECT NDB. Understanding the pattern of normal distribution in IQ-SPECT short-time acquisitions with and without ACSC will be helpful for interpretation of imaging findings in patients with coronary artery disease (CAD) or low likelihood of CAD and the NDBs will aid in quantitative analysis.

IQ·SPECT technology and its clinical applications using multicenter normal databases.

IQ·SPECT (Siemens Medical Solutions) is a solution for high-sensitivity and short-time acquisition imaging of the heart for a variable angle general purpose gamma camera. It consists of a multi-focal collimator, a cardio-centric orbit and advanced iterative reconstruction, modeling the image formation physics accurately. The multi-focal collimator enables distance-dependent enlargement of the center region while avoiding truncation at the edges. With the specified configuration and a cardio-centric orbit it can obtain a fourfold sensitivity increase for the heart at the center of the scan orbit. Since IQ·SPECT shows characteristic distribution patterns in the myocardium, appropriate acquisition and processing conditions are required, and normal databases are convenient for quantification of both normal and abnormal perfusion images. The use of prone imaging can be a good option when X-ray computed tomography (CT) is not available for attenuation correction. CT-based attenuation correction changes count distribution significantly in the inferior wall and around the apex, hence image interpretation training and additional use of normal databases are recommended. Recent reports regarding its technology, Japanese Society of Nuclear Medicine working group activities, and clinical studies using 201Tl and 99mTc-perfusion tracers in Japan are summarized.

Regional myocardial damage and active inflammation in patients with cardiac sarcoidosis detected by non-invasive multi-modal imaging.

AIMS: Cardiac sarcoidosis (CS) can be diagnosed using 18F-FDG-PET/CT (PET), cardiovascular magnetic resonance (CMR), and 123I-BMIPP/201TlCl dual myocardial SPECT. This study aims to clarify the relationships among the three modalities with respect to CS. METHODS AND RESULTS: We evaluated 16 patients (male n = 11; age 55 ± 13 years) with confirmed CS who underwent PET, CMR, and dual SPECT with gated SPECT before starting steroid therapy. The left ventricular myocardium was divided into 17 segments to obtain SUVmax for PET images, defect scores from 0 to 4 (0 normal; 4 absent), and mismatch scores for dual SPECT (BMDS, TLDS, and MS) images and late gadolinium enhancement (LGE) scores (0 none; 1 partly positive; 2 homogeneous) on CMR images. Summed BMDS, TLDS, and MS were 18.6 ± 12.6, 12.9 ± 10.9, and 5.7 ± 3.1, respectively. The segmental BMDS and TLDS scores became significantly higher as the LGE scores increased. The MS scores were significantly higher in areas of LGE with a score of 1 than 0 (both, p < 0.001), but did not significantly differ between areas with LGE scores of 1 and 2. The SUVmax was significantly higher in LGE areas with a score of 1 than 0 (p < 0.025), but did not significantly differ between those with scores of 1 or 2. CONCLUSION: Regions with a higher SUVmax indicating active myocardial inflammation were mainly located in areas with LGE, where BMIPP and TL mismatches were evident in patients with CS.

Optimization of scan initiation timing after 11C-methionine administration for the diagnosis of suspected recurrent brain tumors.

OBJECTIVE: 11C-Methionine (MET) positron emission tomography (PET) imaging is a valuable technique for the evaluation of primary and recurrent brain tumors. Many studies have used MET-PET for data acquisition starting at 20 min after the tracer injection, while others have used scan initiation times at 5-15 min postinjection. No previous studies have identified the best acquisition timing during MET-PET imaging for suspected recurrent brain tumors. Here we sought to determine the optimal scan initiating timing after MET administration for the detection of recurrent brain tumors. MATERIALS AND METHODS: Twenty-three consecutive patients with suspected recurrent brain tumors underwent MET-PET examinations. Brain PET images were reconstructed from the four serial data sets (10-15, 15-20, 20-25, and 25-30 min postinjection) that were obtained using the list-mode acquisition technique. We determined the maximal standardized uptake values (SUVmax) of the target lesions and the target-to-normal-tissue ratios (TNRs), calculated as the SUVmax to the SUVmean of a region of interest placed on the normal contralateral frontal cortex. Target lesions without significant MET uptake were excluded. RESULTS: Thirty-one lesions from 23 patients were enrolled. There were no significant differences in MET SUVmax or TNR values among the PET images that were reconstructed with the data extracted from the four phases postinjection. CONCLUSION: The MET uptake in the suspected recurrent brain tumors was comparable among all data extraction time phases from 10 to 30 min postinjection. The scan initiation time of MET-PET at 10 min after the injection is allowable for the detection of recurrent brain tumors. The registration identification number of the original study is 1002.

In vivo validation of gated myocardial SPECT imaging for quantification of small hearts: comparison with cardiac MRI.

BACKGROUND: In patients with small hearts, the Quantitative Gated single-photon emission computed tomography (SPECT) (QGS) program frequently underestimates the left ventricular (LV) end-systolic volume (ESV) and overestimates the ejection fraction (EF). A newly developed cardiac software program, cardioREPO/EXINI heart (cREPO), has been proposed to more accurately quantify small hearts using active shape modeling and a volume-dependent edge correction algorithm for LV delineation. The aim of this study was to validate cREPO in vivo for measuring the LV volumes and EF of both small and non-small hearts, in comparison with values obtained via cardiac MRI (CMR). METHODS: We performed stress (99m)Tc-MIBI SPECT and CMR within a 30-day interval for 44 patients (mean age, 66 years; 27 men). Resting EF, end-diastolic volume (EDV), and ESV with QGS and cREPO were compared with values obtained via CMR. RESULTS: The subjects consisted of 17 small and 27 non-small hearts. CMR yielded EDV, ESV, and EF values of 135 ± 31 ml (mean ± SD, range 85-217 ml), 57 ± 21 ml (27-105 ml), and 60 ± 6 % (45-70 %), respectively. Compared with CMR, both QGS and cREPO systematically underestimated both EDV and ESV and overestimated EF. The magnitude of the overestimation of EF by QGS, compared with CMR, correlated strongly with the given EF values (r = 0.71, P < 0.0001). In contrast, no significant correlation was seen with cREPO (r = 0.18, P = 0.24). In addition, no significant correlation was found between the magnitude of the underestimation of ESV and heart size with cREPO (r = 0.03, P = 0.83). Thus, cREPO provided a relatively constant 9 % overestimation of EF values relative to CMR, for the studied EF range for both small and non-small hearts. CONCLUSIONS: The use of the new algorithm of cREPO ameliorated exaggerated EF in small hearts but not resolved completely. The program provided a constant 9 % overestimation for both small and non-small hearts, which should be carefully taken into account for clinical assessment of LV function.

Diagnosis and Detection of Myocardial Injury in Active Cardiac Sarcoidosis--Significance of Myocardial Fatty Acid Metabolism and Myocardial Perfusion Mismatch.

BACKGROUND: Myocardial injury can be detected more sensitively using (123)I-radioiodinated 15-(p-iodophenyl)-3(R,S)-methylpentadecanoic acid (BMIPP) than thallium-201 (TL). The present study investigated whether (18)F-fluorodeoxyglucose-positron emission tomography (FDG-PET) uptake as an index of active inflammation in patients with cardiac sarcoidosis (CS) is associated with BMIPP and TL findings, and whether dual single-photon emission computed tomography (SPECT) can facilitate diagnosis of CS. METHODS AND RESULTS: We retrospectively enrolled 52 consecutive patients with suspected CS who were assessed on FDG-PET/computed tomography (CT) and BMIPP/TL dual SPECT. The SPECT images were divided into 17 segments and then BMIPP and TL total defect scores (BMDS, TLDS) as well as mismatch scores (BMDS-TLDS: sumMS) were calculated. Maximum standardized uptake value (SUVmax) in the entire myocardium was obtained from FDG-PET/CT. SUVmax was much higher in patients with, than without CS (P<0.0001). BMDS was higher and sumMS much higher in CS (P<0.05 and P<0.0001, respectively). The sensitivity and specificity of sumMS to detect CS were 74% and 80%, respectively. SUVmax was not associated with either BMDS or sumMS in the patients with CS. On multivariate analysis, the combination of sumMS and SUVmax had greater prognostic significance compared with each parameter on its own. CONCLUSIONS: BMIPP and TL dual-tracer mismatch is a useful finding to diagnose CS, and adds greater diagnostic value to SUVmax on FDG-PET/CT.

Comparison of situs ambiguous patterns between heterotaxy syndromes with polysplenia and asplenia.

OBJECTIVES: To compare the differences of visceral anomalies shown by computed tomography (CT) in patients with polysplenia syndrome (PS) or asplenia syndrome (AS). METHODS: This retrospective study was approved by the institutional review board, and informed consent was waived. Thirty-one patients with PS and 29 patients with AS underwent chest-abdominal CT. The evaluated CT findings were as follows: the orientation of stomach, liver and gallbladder; short pancreas; azygous/hemiazygous continuation; ipsilateral position of the inferior vena cava and aorta; preduodenal portal vein; abnormal confluence of renal vein (defined as renal vein drains to the inferior vena cava or azygous/hemiazygous vein at the upper level of celiac trunk origin); gastrointestinal malrotation; and tracheobronchial tree. RESULTS: Azygous/hemiazygous continuation was seen in 74% (20 of 27)/0% (0 of 28) of PS/AS (P<0.0001), bilateral hyparterial bronchi in 75% (24 of 32)/5% (1 of 22), bilateral eparterial bronchi in 9% (3 of 32)/95% (21 of 22), ipsilateral position of the inferior vena cava and aorta in 59% (16 of 27)/89% (25 of 28), and abnormal confluence of renal vein in 7% (2 of 27)/57% (16 of 28), respectively. No significant differences were found in the other anomalies. CONCLUSION: Significant differences in anomalous systemic venous connections and tracheobronchial anomaly were observed between PS and AS. Abnormal confluence of renal vein is relatively rare anomalous venous connections, but frequently observed in AS.

Differentiation of Brain Tumor Recurrence from Post-Radiotherapy Necrosis with 11C-Methionine PET: Visual Assessment versus Quantitative Assessment.

PURPOSE: The aim of this multi-center study was to assess the diagnostic capability of visual assessment in L-methyl-11C-methionine positron emission tomography (MET-PET) for differentiating a recurrent brain tumor from radiation-induced necrosis after radiotherapy, and to compare it to the accuracy of quantitative analysis. METHODS: A total of 73 brain lesions (glioma: 31, brain metastasis: 42) in 70 patients who underwent MET-PET were included in this study. Visual analysis was performed by comparison of MET uptake in the brain lesion with MET uptake in one of four regions (around the lesion, contralateral frontal lobe, contralateral area, and contralateral cerebellar cortex). The concordance rate and logistic regression analysis were used to evaluate the diagnostic ability of visual assessment. Receiver-operating characteristic curve analysis was used to compare visual assessment with quantitative assessment based on the lesion-to-normal (L/N) ratio of MET uptake. RESULTS: Interobserver and intraobserver κ-values were highest at 0.657 and 0.714, respectively, when assessing MET uptake in the lesion compared to that in the contralateral cerebellar cortex. Logistic regression analysis showed that assessing MET uptake in the contralateral cerebellar cortex with brain metastasis was significantly related to the final result. The highest area under the receiver-operating characteristic curve (AUC) with visual assessment for brain metastasis was 0.85, showing no statistically significant difference with L/Nmax of the contralateral brain (AUC = 0.89) or with L/Nmean of the contralateral cerebellar cortex (AUC = 0.89), which were the areas that were the highest in the quantitative assessment. For evaluation of gliomas, no specific candidate was confirmed among the four areas used in visual assessment, and no significant difference was seen between visual assessment and quantitative assessment. CONCLUSION: The visual assessment showed no significant difference from quantitative assessment of MET-PET with a relevant cut-off value for the differentiation of recurrent brain tumors from radiation-induced necrosis.

Prognostic Value of Total Lesion Glycolysis Measured by 18F-FDG-PET/CT in Patients with Colorectal Cancer.

AIM: [(18)F]Fluorodeoxyglucose positron-emission tomography with computed tomography ((18)F-FDG-PET/CT) was assessed regarding its utility in prediction of outcomes after curative resection of colorectal cancer. PATIENTS AND METHODS: Preoperative (18)F-FDG-PET/CT was performed in 325 patients with colorectal cancer. Maximum standardized uptake value (SUVmax), mean SUV (SUVmean), metabolic volume (MV), and total lesion glycolysis (TLG) were measured. Patients were divided into groups using cut-offs for overall survival (OS). (18)F-FDG-PET/CT parameters and other clinicopathological factors were investigated as prognostic factors. RESULTS: The 5-year OS rates in the low and high SUVmax, SUVmean, MV, and TLG groups were 91.4% and 87.0% (p=0.238), 90.8% and 88.2% (p=0.453), 91.7% and 83.8% (p=0.006), and 92.1% and 70.1% (p=0.001), respectively, indicating poorer outcomes in patients with high MV and TLG. In multivariate analysis, high TLG, age ≥65 years, rectal tumor location, and pN(+) were independent factors predicting a poor prognosis. CONCLUSION: TLG in (18)F-FDG-PET/CT is a prognostic parameter for colorectal cancer after curative resection.

FDG-PET/CT and CT Findings of a Benign Solitary Fibrous Tumor of the Kidney; Correlation with Pathology.

Herein, we report the F-18 fluorodeoxyglucose ((18)F-FDG) positron emission tomography (PET)/computed tomography (CT) findings of a benign solitary fibrous tumor (SFT) of the kidney. The patient was a 63-year-old woman with a mass in the right kidney (10×9.7 cm), incidentally found on CT images. The CT scan showed a lobulated tumor arising from the hilum of the right kidney. The tumor consisted of two components with different patterns of enhancement. Most of the tumor demonstrated moderate enhancement from the corticomedullary to nephrographic phase. A small nodular component at the caudal portion of the tumor showed avid enhancement in the corticomedullary phase and rapid washout in the nephrographic phase in contrast-enhanced CT. FDG-PET/CT was performed and showed weak FDG accumulation (SUVmax=2.30 and 1.91 in the main and small caudal components). Although renal cell carcinoma was preoperatively diagnosed, histopathological examination revealed renal SFT, with no malignant potential. Therefore, when a renal tumor with contrast-medium enhancement and low FDG accumulation is demonstrated, SFT should be considered as a differential diagnosis in addition to renal cell carcinoma.

Japanese consensus guidelines for pediatric nuclear medicine. Part 1: Pediatric radiopharmaceutical administered doses (JSNM pediatric dosage card). Part 2: Technical considerations for pediatric nuclear medicine imaging procedures.

The Japanese Society of Nuclear Medicine has recently published the consensus guidelines for pediatric nuclear medicine. This article is the English version of the guidelines. Part 1 proposes the dose optimization in pediatric nuclear medicine studies. Part 2 comprehensively discusses imaging techniques for the appropriate conduct of pediatric nuclear medicine procedures, considering the characteristics of imaging in children.

Prognostic value of (123)I-betamethyl-p-iodophenyl-pentadecanoic acid single-photon emission computed tomography in diabetic patients with suspected ischemic heart disease.

BACKGROUND: Because of their high risk for cardiovascular events, we investigated the role of (123)I-betamethyl-p-iodophenyl-pentadecanoic acid (BMIPP) SPECT in evaluating the prognosis of diabetic patients with suspected coronary heart disease. METHODS AND RESULTS: We retrospectively registered 186 diabetic patients with suspected coronary heart disease, but no previous diagnosis of heart disease, who had been examined by BMIPP and thallium (TL) dual SPECT. They were followed for over 2 years. The dual SPECT images were scored to obtain summed defect scores for each SPECT image (BMDS, TLDS and mismatch score [MS]). The primary endpoint was the first incidence of all-cause cardiac events. The secondary endpoint was cardiac death. Clinical classical risk factors in addition to the stage of chronic kidney disease (CKD), as well as cardiac function, were included in the prognostic analysis. Cardiac events occurred in 39 patients, including 8 cardiac deaths. Kaplan-Meier analysis revealed significantly more frequent cardiac event rates in patients with than without MS ≥5 or BMDS ≥6 (P<0.0001). Cox hazard multivariate analysis showed that MS and CKD stage or BMIPP and CKD stage were independent predictors. Only hemodialysis was a significant prognostic indicator for cardiac death. CONCLUSIONS: BMIPP SPECT when combined with CKD stage accurately predicts cardiac events among diabetic patients with suspected ischemic heart disease.

Accelerated BMIPP uptake immediately after reperfused ischemia in the isolated rat heart model.

OBJECTIVE: 123I-beta-methyl iodophenyl pentadecanoic acid (BMIPP) can visualize myocardial fatty acid metabolism and has extensive potential for diagnosing cardiac diseases such as acute coronary syndrome in the clinical setting. Increased BMIPP uptake with decreased perfusion occasionally occurs under acute reperfusion ischemia and the kinetics of BMIPP remain unclear. The present study uses the isolated rat heart model to measure kinetic changes in BMIPP under acute reperfusion ischemia. METHODS: Male Wistar rats were allotted to normal control (NG), mild (MG) and severe (SG) ischemia groups. The hearts were perfused according to the Langendorff method at a constant flow rate, and BMIPP wash-in and wash-out were studied. No-flow ischemia was applied for 15 and 30 min to the MG and SG groups, followed immediately by the wash-in and wash-out study. Whole heart radioactivity was determined using an external gamma detector throughout the experiment. Rates of myocardial uptake (K1, mL/min) and clearance (k2, min(-1)) were generated using a compartmental model analysis. The same procedures and protocols were performed using (99m)Tc-sestamibi (MIBI) as a perfusion study. RESULTS: Perfusion pressure significantly increased and mean heart rate significantly decreased in the severe ischemia group (heart rate: 244 ± 76, 304 ± 105 and 94 ± 140 bpm; perfusion pressure: 67 ± 13, 101 ± 31 and 160 ± 84 mmHg for NG, MG and SG, respectively). MIBI-K1 significantly decreased, whereas BMIPP-K1 increased in the MG and SG groups (MIBI-K1: 3.45 ± 1.10, 1.95 ± 0.82, and 1.05 ± 0.13 mL/min; BMIPP-K (1): 3.06 ± 0.88, 3.91 ± 0.87, and 4.94 ± 1.51 mL/min for NG, MG and SG, respectively) with an inverse relationship to the severity of ischemia. MIBI-k2 increased markedly in severe ischemia (NG vs. MG: p < 0.05), whereas BMIPP-k2 did not change in the ischemic groups (MIBI-k2: 0.00072 ± 0.0011, 0.00038 ± 0.00076 and 0.043 ± 0.033; BMIPP-k2: 0.0056 ± 0.0028, 0.0029 ± 0.0010 and 0.0037 ± 0.0022 min(-1) for NG, MG and SG, respectively). CONCLUSION: Myocardial BMIPP uptake increased immediately upon reperfusion after no-flow ischemia, and was inversely related to the severity of ischemia. The increased uptake was not due to reduced clearance, but to accelerated extraction.

Long-term prognostic stratification by a combination of (123)I-metaiodobenzylguanidine scintigraphy and ejection fraction in dilated cardiomyopathy.

OBJECTIVE: (123)I-metaiodobenzylguanidine (MIBG) scintigraphy is a useful tool for predicting the prognosis in patients with congestive heart failure; however, little is known regarding long-term prognostic evaluations. The aim of this study was to evaluate long-term prognosis in a roughly 10-year period, in dilated cardiomyopathy (DCM) by MIBG imaging, compared to other conventional functional parameters. METHODS: Eighty-six DCM patients (50 ± 14 years of age, 57 males) underwent MIBG imaging, at 15 min and 4 h after tracer injection, from which the delayed heart to mediastinum ratio (H/M) and washout rate (WR) were obtained. The left ventricular ejection fraction (EF) and end-diastolic diameter (LVDd) were also measured by echocardiogram. All patients were followed up for 8-14 years, and the death event was investigated. RESULTS: Kaplan-Meier curves revealed a poor prognosis only in the group above the third quartile of WR (=50%) (10-year prognosis, 35%); however, there were no statistically significant differences in prognosis among the other 3 groups (10-year prognosis, 75-84%). A Cox hazard univariate analysis selected WR (p = 0.0004), H/M (p < 0.0001), EF (p = 0.0024), and LVDd (p = 0.0189) as significant prognostic indicators. Multivariate analysis revealed the H/M (p = 0.0023) and EF (p = 0.024) to be an independent prognostic predictor. The 10-year prognosis of patients with both WR < 50% and EF > 30%; WR < 50% and EF < 30%; and both WR > 50% and EF < 30% were 89, 71, and 33%, respectively. These three groups were well stratified, significantly (log-rank test: χ (2) = 30.0, p < 0.0001). However, even patients with WR ≥ 50% had few death events after 3 years following MIBG imaging. CONCLUSIONS: The MIBG parameter, delayed H/M or WR combined with the EF is a useful tool for the prediction of a long-term prognosis in DCM, which is superior to MIBG parameters alone. However, patients with WR > 50% but no event in a 3-year follow-up period should undergo an additional MIBG imaging for prognostic prediction.

Comparison of parameters of (123)I-metaiodobenzylguanidine scintigraphy for differential diagnosis in patients with parkinsonism: correlation with clinical features.

OBJECTIVES: The purpose of this study was to estimate the diagnostic accuracy of (123)I-metaiodobenzylguanidine (MIBG) scintigraphy to diagnose Lewy body disease (LBD), including Parkinson's disease (PD) and dementia with Lewy bodies, and to clarify the relationship between MIBG parameters and the clinical findings. METHODS: One hundred-and-forty-four patients with parkinsonism without diabetes mellitus or a history of cardiac disease were retrospectively selected in the study. Clinical diagnosis was confirmed by follow-up during more than 6 months by neurologists. All patients underwent MIBG imaging at 15 min (initial) and 4 h (delayed) after the tracer injection, and clinical features such as Hoehn and Yahr (H-Y) classification or symptoms specific to parkinsonism were also investigated. The heart to mediastinum ratio (H/M) and the washout ratio (WR) of MIBG were calculated, and correlation with the clinical features was analyzed. RESULTS: Ninety-seven and 47 patients were diagnosed as LBD and Parkinson's syndrome (PS), respectively. Initial and delayed H/M were significantly lower and WR was significantly higher in LBD than in PS (p < 0.0001). The initial H/M was independently correlated with tremor (F value 10.45), hesitation (F = 4.49), and hallucinations (F = 5.09) (p < 0.0001). The sensitivity and specificity for the diagnosis of LBD were 64.9 and 87.2% with initial H/M, 78.4 and 68.1% with delayed H/M, and 80.4 and 61.7% with WR, respectively. Using multivariate analysis, initial H/M (F = 39.33) and tremor (F = 10.46) were independently correlated to the diagnosis of LBD (r = 0.562, p < 0.0001) among the MIBG and various clinical parameters. CONCLUSION: The initial H/M was the most useful of the 3 different parameters of MIBG for the diagnosis of LBD, but had low sensitivity. WR and delayed H/M had no incremental value to initial H/M for the diagnosis of PD. Careful long-term follow-up is needed for patients with parkinsonism who are clinically diagnosed as LBD with normal initial H/M, or diagnosed as no LBD with low initial H/M.

Asynchronous contraction of the 2 ventricles caused by ventricular pacing after a Fontan-type operation in a patient with a biventricular heart.

We treated a 6-year-old boy who had polysplenia syndrome and tetralogy of Fallot with a small right ventricle (RV), an atrial septal defect, a hemiazygos connection, and bilateral superior vena cava. Because the RV was too small for a biventricular repair to be performed, the patient underwent a total cavopulmonary shunt operation although his heart was biventricular and a pacemaker (VVI) had been implanted for management of the sick sinus syndrome complicated by polysplenia syndrome. After the operation, marked asynchronous contraction was noted between the morphological right and left ventricles and was probably responsible for the low cardiac output noted in this patient. In order to clarify the significance of the asynchronous contraction, we determined the cause of the low cardiac output by studying the time course of the volume changes in the morphological right and left ventricles during a cardiac cycle by using angiograms. In addition, we studied the interventricular flow dynamics by using pulsed-Doppler echocardiography. After a Fontan-type operation is performed on patients with a biventricular heart, the 2 ventricles may not function in perfect coordination when they have to work as 1 unit. These patients are likely to develop cardiac dysfunction due to interventricular to-and-fro flow dynamics. Asynchronous contraction between the 2 ventricles caused by abnormal interventricular conduction impaired the cardiac performance in the present case.

Myocardial 99mTc-sestamibi extraction and washout in hypertensive heart failure using an isolated rat heart.

PURPOSE: Myocardial mitochondria are the primary part of energy production for healthy cardiac contraction. And mitochondrial dysfunction would play an important role in progressive heart failure. In the recent years, myocardial washout of (99m)Tc-sestamibi [((99m)Tc-hexakis-2-methoxy-2-methylpropyl isonitrile (MIBI)] has been introduced to be a potential marker in patients with heart failure. The objective of this study was to clarify MIBI extraction and washout kinetics using isolated perfusion system in hypertension induced model of myocardial dysfunction. METHODS: Six-week-old Dahl-salt sensitive rats, allotted to 4 groups; a 5-week high-salt group (5 wk-HS), 12-week high-salt group (12 wk-HS) and two age-matched, low-salt diet control groups (5 wk-LS and 12 wk-LS). The rats in 5 wk-HS and 12 wk-HS groups were fed a high-salt diet (containing 8% NaCl). Cardiac function was examined by echocardiography before removing heart. Hearts were perfused according to the Langendorff method at a constant flow rate, in which 20-min MIBI washin was conducted followed by 25-min MIBI washout. Whole heart radioactivity was collected every sec by an external gamma detector. The myocardial extraction, K(1) (ml/min) and washout rate, k(2) (min(-1)) were generated. RESULTS: High-salt diet groups showed significant high-blood pressure. Echocardiography revealed thickened LV walls in 5 wk-HS, and reduced cardiac function in 12 wk-HS, compared to each age-matched control group. K(1) showed no significant difference among all groups (5 wk-HS: 2.36 ± 1.07, 5 wk-control: 2.59 ± 0.28, 12 wk-HS: 1.91 ± 0.90, and 12 wk-control: 2.84 ± 0.57). k(2) in 5 wk-HS was comparable to that in the age matched control group (0.00030 ± 0.00039 vs -0.000010 ± 0.00044), but it was increased remarkably in 18 wk-HS compared to the age matched control group (0.0025 ± 0.0011 vs 0.000025 ± 0.000041, P<.01), and 5 wk-HS (P<.01). CONCLUSION: In the course of hypertensive heart disease, MIBI washout was increased in the transitional state from hypertrophied to dilated and failing heart, while MIBI extraction remained intact.

Ability of 18F-FDG PET/CT to diagnose recurrent colorectal cancer in patients with elevated CEA concentrations.

OBJECTIVE: Elevated levels of serum carcinoembryonic antigen (CEA) in patients with colorectal cancer (CRC) during follow-up suggest recurrence, which can be visualized by (18)F-FDG PET/CT. Since the magnitude of CEA elevation reflects cancer volume, the ability of PET/CT to detect recurrence in patients with only mildly elevated CEA might be limited. However, the accuracy of PET/CT in detecting recurrence associated with elevated CEA has not been fully assessed. We retrospectively evaluated the diagnostic performance of (18)F-FDG PET/CT postoperatively relative to CEA levels among patients with CRC. METHODS: We visually assessed 75 PET/CT evaluations of 57 postoperative patients with CEA >5.0 ng/ml. Tumor volumes were also determined using image analysis software. The final diagnosis was confirmed based on histopathological findings, or at least on 6 months of clinical follow-up. RESULTS: Two lung cancers were excluded and we finally analyzed data from 73 of the 75 PET/CT evaluations. Recurrences were diagnosed in 54 (prevalence 74%). The sensitivity and specificity of PET/CT to detect recurrence was 50/54 (93%) and 14/19 (74%), respectively. The positive and negative predictive values were 91 and 78%, respectively, and the positive and negative likelihood ratios were 3.52 and 0.10, respectively. Values for the sensitivity of PET/CT were 88 and 95%, and those for specificity were 78 and 70%, at serum CEA concentrations of 5-10 and >10 ng/ml, respectively. Serum CEA (r = 0.500, p < 0.001) significantly correlated with cancer volumes. CONCLUSIONS: The present findings showed that (18)F-FDG PET/CT could accurately detect recurrent CRC irrespective of the elevated CEA concentration.

Ability of 201Tl and 123I-BMIPP mismatch to diagnose myocardial ischemia in patients with suspected coronary artery disease.

OBJECTIVE: A mismatch defect between (201)TL and (123)I-BMIPP dual isotope SPECT (d-SPECT) is useful to detect myocardial ischemia in patients with acute coronary syndrome. However, whether mismatched d-SPECT findings reflect actual myocardial ischemia in stable patients with suspected, but unknown ischemic heart disease is unclear. The present study assesses the significance of a d-SPECT mismatch among such patients. METHODS: Forty-nine patients with suspected stable coronary heart disease who had been referred for chest pain, ECG abnormalities or multiple risk factors (66 +/- 11 years old, 34 males) with a d-SPECT mismatch participated in this study. All of them underwent coronary angiography (CAG) to assess coronary artery disease. The entire myocardial area on d-SPECT images was divided into 17 segments, each of which was scored from 0 (normal) to 4 (defect). The d-SPECT mismatch score (MS) was defined as the summed BMIPP defect score (BM-TDS) minus the summed defect score (TL-TDS). The inclusion criterion was MS >or= 1, and the mismatch was defined as true positive if the mismatched area was concordant with the territories supplied by significant coronary stenotic arteries by CAG. RESULTS: Ischemic heart disease was judged by coronary angiography in 31 (63%) patients (IHD group), of which 24 (49.0%) were true positives. Of the remaining 18 (37%) patients without no significant coronary stenosis (non-IHD group), 12 (24%) had some types of organic heart disease. If MS >or= 4 was defined as the threshold for an ischemic positive mismatch, then the sensitivity and specificity were 80% and 63%, respectively. However, mismatch scores did not significantly differ between the groups with true positive-IHD and organic heart disease in non-IHD group (6.6 +/- 4.4 vs. 6.4 +/- 3.7). CONCLUSION: A d-SPECT mismatch score of >or=4 was an appropriate cutoff at which diagnosis of myocardial ischemia in patients who were screened for ischemic heart disease. However, since patients with non-ischemic but organic heart disease can also present with abnormal mismatch findings, coronary angiography or CT might be warranted to differentiate IHD from non-IHD.