Evaluation of Coronary Circulation by 13N-Ammonia Myocardial Perfusion Positron Emission Tomography in Patients with Right Coronary Artery Occlusion Due to Kawasaki Disease.

BACKGROUND: Although occlusion of the right coronary artery (RCA) is common in the remote stages of Kawasaki disease, revascularization of the RCA is challenging in children and is usually managed by observation without intervention. METHODS: Using adenosine-stress 13N-ammonia myocardial perfusion positron emission tomography, we evaluated coronary circulation in 14 patients (12 males) with RCA occlusion to identify ischemia (myocardial flow ratio < 2.0) in the RCA region and examined hemodynamics, cardiac function, and coronary aneurysm diameter. These variables were also compared in patients with/without RCA segmental stenosis (SS). RESULTS: There were five cases of ischemia in the RCA region. RCA myocardial blood flow (MBF) at rest was higher in patients with ischemia than in those without ischemia, but the difference was not significant (1.27 ± 0.21 vs. 0.82 ± 0.16 mL/min/g, p = 0.2053). Nine patients presented with RCA SS, and age at onset of Kawasaki disease tended to be lower in those with SS. The maximum aneurysm diameter of RCA was significantly smaller in patients with SS (10.0 ± 2.8 vs. 14.7 ± 1.6, p = 0.0239). No significant differences in other variables were observed between patients with/without ischemia and SS. CONCLUSIONS: At rest, MBF in the RCA region was relatively well preserved, even in patients with RCA occlusion, and there was no progressive deterioration in cardiac function. Adenosine stress showed microcirculatory disturbances in only half of the patients, indicating that it is reversible in children with Kawasaki disease.

Preoperative analysis of factors associated with prolonged pneumoretroperitoneum time during retroperitoneal laparoscopic nephroureterectomy for upper tract urothelial carcinoma.

BACKGROUND: Prolonged laparoscopic nephroureterectomy (LNU) for upper tract urothelial cancer (UTUC) can increase the frequency of intravesical recurrence after surgery. Therefore, it is important for urological surgeons to have knowledge on preoperative risk factors for prolonged LNU. However, few studies have investigated the risk factors for prolonged LNU. We hypothesized that the quantity of perirenal fat affects the pneumoretroperitoneum time (PRT) of retroperitoneal LNU (rLNU). This study aimed to investigate the preoperative risk factors for prolonged PRT during rLNU. METHODS: We reviewed the data of 115 patients who underwent rLNU for UTUC between 2013 and 2021. The perirenal fat thickness (PFT) observed on preoperative computed tomography (CT) images was used to evaluate the perinephric fat quantity. Preoperative risk factors for PRT during rLNU were analyzed using logistic regression models. The cutoff value for PRT was determined based on the median time.The cutoff values for fat-related factors influencing PRT were defined according to receiver operating characteristic curve analysis. RESULTS: The median PRT for rLNU was 182 min (interquartile range, 155-230 min). The cutoff values of posterior, lateral, and anterior PFTs were 15 mm, 24 mm, and 6 mm, respectively. Multivariate analysis revealed that a posterior PFT ≥ 15 mm (odds ratio [OR], 2.72; 95% confidence interval, 1.04-7.08; p = 0.0410) was an independent risk factor for prolonged PRT. CONCLUSIONS: Thick posterior PFT is a preoperative risk factor for prolonged PRT during rLNU. For patients with UTUC and thick posterior PFT, surgeons should develop optimal surgical strategies, including the selecting an expert surgeon as a primary surgeon and the selecting transperitoneal approach to surgery or open surgery.

Determining the clinicopathological significance of the VI-RADS ≧4 group: a retrospective study.

BACKGROUND: The Vesical Imaging Reporting and Data System (VI-RADS) is widely used for predicting muscle-invasive bladder cancer (MIBC). This study aimed to determine the clinicopathological significance of the VI-RADS ≧4 (VI≧4) group. METHODS: Patients who underwent transurethral resections of bladder tumors during the study period and preoperative magnetic resonance imaging were considered. The patients were pathologically diagnosed with urothelial carcinoma (UC). We first compared the results of patients with VI-RADS scores of 3 and 4 to determine the cut-off score for MIBC; thereafter, the patients were divided into the VI≧4 and VI-RADS ≦3 (VI≦3) groups using VI-RADS. The clinicopathological significance of the VI≧4 group was examined retrospectively by comparing the characteristics of each group. RESULTS: In total, 121 cases were examined, of which 28 were pathologically diagnosed with MIBC. Of the 28 MIBC cases, three (10.7%) had a VI-RADS score of ≦3, and 25 (89.3%) had a VI-RADS score of ≧4. Of the 93 NMIBC cases, 86 (92.5%) had a VI-RADS score of ≦3, and seven (7.5%) had a VI-RADS score of ≧4. The diagnostic performance of the VI-RADS with a cut-off score of 4 was 89.3% for sensitivity, 92.5% for specificity, and an area under the curve (AUC) of 0.91. Contrastingly, for a cut-off score of 3, the sensitivity was 89.3%, specificity was 62.0%, and AUC was 0.72. A VI-RADS score of ≥ 4 could predict MIBC. In the VI≧4 group, 30 of 32 (93.8%) patients had high-grade tumors. The VI≧4 group had significantly more high-grade bladder cancers than the VI≦3 group (p < 0.001 OR = 31.77 95%CI:8.47-1119.07). In addition, the VI≧4 group had more tumor necrosis (VI≧4 vs VI≦3, p < 0.001 OR = 7.46 95%CI:2.61-21.34) and more UC variant cases (VI≧4 vs VI≦3, p = 0.034 OR = 3.28 95%CI:1.05-10.25) than the VI≦3 group. CONCLUSIONS: This study suggests that VI-RADS has a high diagnostic performance in predicting MIBC and that VI-RADS could diagnose high-grade tumors, necrosis, and UC variants.

Primary leiomyoma of the bladder radiologically mimicking a retroperitoneal tumor - a case report.

The case presented is of a 47-year-old patient with an extravesical pedunculated bladder leiomyoma, which was difficult to distinguish from a retroperitoneal tumor. Preoperatively, it was suspected to be a retroperitoneal tumor and a laparotomy with tumor resection was performed. lntraoperatively, the bladder and tumor were connected by a cord-like tissue. A retrospective review of preoperative images revealed that cord-like tissue, identified intraoperatively, was also present. Bladder leiomyomas can grow as extravesical pedunculated tumors. Therefore, when the continuity between the bladder and tumor is only a cord-like object, the finding ofcontinuity is useful to diagnose with bladder leiomyoma. J. Med. Invest. 70 : 513-515, August, 2023.

Perirenal fat stranding as a predictor of disease progression after radical nephroureterectomy for renal pelvic urothelial carcinoma: a retrospective study.

BACKGROUND: To investigate the impact of Perirenal fat stranding (PRFS) on progression after radical nephroureterectomy (RNU) for renal pelvic urothelial carcinoma (RPUC) without hydronephrosis and to reveal the pathological findings of PRFS. METHODS: Clinicopathological data, including computed tomography (CT) findings of the ipsilateral PRFS, were collected from the medical records of 56 patients treated with RNU for RPUC without hydronephrosis between 2011 and 2021 at our institution. PRFS on CT was classified as either low or high PRFS. The impact of PRFS on progression-free survival (PFS) after RNU was analyzed using the Kaplan-Meier method and log-rank test. In addition, specimens including sufficient perirenal fat from patients with low and with high PRFS were pathologically analyzed. Immunohistochemical analysis of CD68, CD163, CD3, and CD20 was also performed. RESULTS: Of the 56 patients, 31(55.4%) and 25 (44.6%) patients were classified as having low and high PRFS, respectively. Within a median follow-up of 40.6 months postoperatively, 11 (19.6%) patients showed disease progression. The Kaplan-Meier method and log-rank test revealed that patients with high PRFS had significantly lower PFS rates than those with low PRFS (3-year PFS 69.8% vs 93.3%; p = 0.0393). Pathological analysis revealed that high PRFS specimens (n = 3 patients) contained more fibrous strictures in perirenal fat than low PRFS specimens (n = 3 patients). In addition, M2 macrophages (CD163 +) infiltrating fibrous tissue in perirenal area were observed in all patients with high PRFS group. CONCLUSIONS: PRFS of RPUC without hydronephrosis consists of collagenous fibers with M2 macrophages. The presence of ipsilateral high PRFS might be a preoperative risk factor for progression after RNU for RPUC patients without hydronephrosis. Prospective studies with large cohorts are required in the future.

Estimation of Microvascular Dysfunction by Using 13N-Ammonia Positron Emission Tomography with Quantitative Myocardial Blood Flow Analysis in Chronic Coronary Syndrome.

BACKGROUND: Although coronary artery disease (CAD) is characterized by epicardial atherosclerosis and microvascular disease, the importance of evaluating microvascular dysfunction has not been sufficiently recognized in clinical practice. We estimated microvascular disease severity by assessing hyperemic microvascular resistance (MVR), as determined by absolute quantification of myocardial blood flow (MBF) with 13N-ammonia positron emission tomography-myocardial perfusion imaging (PET-MPI). METHODS: We retrospectively collected data for 23 CAD patients who underwent both stress/rest PET-MPI and invasive coronary angiography (CAG) with fractional flow reserve (FFR) measurement. Among 30 vessels for which FFR measurement was performed, 13 had a low FFR (FFR ≤0.75). For each patient, myocardial segments of a standard 17-segment model were assigned to the stenotic myocardial area perfused by the FFR-measured vessel and a reference normal-perfusion area based on PET-MPI and the coronary distribution on CAG. Hyperemic MVR was calculated by using the formula, hyperemic MVR = hyperemic mean blood pressure × FFR/hyperemic MBF of the stenotic vessel. RESULTS: A strong negative correlation was observed between hyperemic MVR and hyperemic MBF in the reference normal-perfusion area (R = -0.758, P<0.001). CONCLUSION: Microvascular disease severity in chronic CAD can be estimated by hyperemic MBF of the normal-perfusion area with 13N-ammonia PET-MPI.

External Validation of the Kumamoto Criteria in Transthyretin Amyloid Cardiomyopathy Screening　- A Retrospective Cohort Study.

Background: The Kumamoto criteria have been proposed as a non-invasive screen for transthyretin amyloid cardiomyopathy. This study assessed the validity of the Kumamoto criteria externally. Methods and Results: The study included 138 patients (median age 73 years; 65% male) who underwent 99 mTc-pyrophosphate (PYP) scintigraphy. Patients were divided into 4 groups according to total scores on the Kumamoto criteria (i.e., 0-3) for the following 3 factors: high-sensitivity cardiac troponin T ≥0.0308 ng/mL, wide (≥120 ms) QRS, and left ventricular posterior wall thickness ≥13.6 mm. The diagnostic performance and positive predictive value (PPV) of the Kumamoto criteria for positive 99 mTc-PYP scintigraphy were validated. Eighteen (13%) patients were positive on 99 mTc-PYP scintigraphy. The Kumamoto criteria had a favorable diagnostic performance (area under the curve 0.808). The PPV for groups with scores of 0, 1, 2, and 3 was 0% (n=0/42), 11% (n=6/57), 21% (n=7/33), and 83% (n=5/6), respectively, which is lower, particularly for those with a score of 2, than in the original Kumamoto cohort. However, the PPV increased after combining the Kumamoto criteria with a history of orthopedic diseases (spinal canal stenosis and/or carpal tunnel syndrome). Conclusions: This study suggests that the Kumamoto criteria have a favorable diagnostic performance; however, the PPV may decrease depending on the study population. Combining the Kumamoto criteria with the presence of orthopedic disease may improve the PPV.

Differential diagnosis and prognosis of small renal masses: association with collateral vessels detected using contrast-enhanced computed tomography.

BACKGROUND: Active surveillance (AS) is one of the treatment methods for patients with small renal masses (SRMs; < 4 cm), including renal cell carcinomas (RCCs). However, some small RCCs may exhibit aggressive neoplastic behaviors and metastasize. Little is known about imaging biomarkers capable of identifying potentially aggressive small RCCs. Contrast-enhanced computed tomography (CECT) often detects collateral vessels arising from neoplastic angiogenesis in RCCs. Therefore, this study aimed to evaluate the association between SRM differential diagnoses and prognoses, and the detection of collateral vessels using CECT. METHODS: A total of 130 consecutive patients with pathologically confirmed non-metastatic SRMs (fat-poor angiomyolipomas [fpAMLs; n = 7] and RCCs [n = 123]) were retrospectively enrolled. Between 2011 and 2019, SRM diagnoses in these patients were confirmed after biopsy or surgical resection. All RCCs were surgically resected. Regardless of diameter, a collateral vessel (CV) was defined as any blood vessel connecting the tumor from around the kidney using CECT. First, we analyzed the role of CV-detection in differentiating between fpAML and RCC. Then, we evaluated the sensitivity, specificity, positive predictive value (PPV), negative predictive value (NPV), and accuracy of RCC diagnosis based on CV-detection using CECT. We also assessed the prognostic value of CV-detection using the Fisher exact test, and Kaplan-Meier method and the log-rank test. RESULTS: The sensitivity, specificity, PPV, NPV, and accuracy of CV-detection for the diagnosis of small RCCs was 48.5, 45.5, 100, 100, and 9.5% respectively. Five of 123 (4.1%) patients with RCC experienced recurrence. CV-detection using CECT was the only significant factor associated with recurrence (p = 0.0177). Recurrence-free survival (RFS) was significantly lower in patients with CV compared with in those without CV (5-year RFS 92.4% versus 100%, respectively; p = 0.005). In addition, critical review of the CT images revealed the CVs to be continuous with the venous vessels around the kidney. CONCLUSIONS: The detection of CVs using CECT is useful for differentiating between small fpAMLs and RCCs. CV-detection may also be applied as a predictive parameter for small RCCs prone to recurrence after surgical resection. Moreover, AS could be suitable for small RCCs without CVs.

Peripheral Coronary Artery Circulatory Dysfunction in Remote Stage Kawasaki Disease Patients Detected by Adenosine Stress 13N-Ammonia Myocardial Perfusion Positron Emission Tomography.

Coronary peripheral circulatory disturbances in the remote stage of Kawasaki disease have been reported. In this study, of the 50 patients in the remote stage of Kawasaki disease who underwent coronary perfusion evaluation using adenosine-loaded 13N-ammonia positron emission tomography, 28 patients who did not have stenosis of ≥75% in the left coronary artery underwent an evaluation for myocardial flow reserve (MFR) of the left anterior descending artery (LAD) and left circumflex artery (LCx). Clinical findings were compared between patients with normal (≥2.0) and abnormal (<2.0) MFRs. In the group with an abnormal MFR in the LAD, the responsiveness of the coronary vascular resistance to adenosine stress decreased even in the LCx (3.50 ± 1.23 vs. 2.39 ± 0.25, p = 0.0100). In the group with an abnormal MFR in the LCx, the responsiveness of the coronary vascular resistance in the LAD also decreased (3.27 ± 1.39 vs. 2.03 ± 0.25, p = 0.0105), and the age of onset of Kawasaki disease tended to be younger in the group with abnormal MFR in the LAD and LCx. We found that the peripheral coronary circulation was extensively impaired in the remote stage of Kawasaki disease, suggesting that an early onset of Kawasaki disease may affect the peripheral coronary circulation in later years.

Serial change in perfusion-metabolism mismatch after coronary artery bypass grafting.

OBJECTIVE: Myocardial ischemia is known to suppress fatty acid metabolism and favor glucose metabolism. However, changes in myocardial metabolism after coronary revascularization are not fully elucidated. METHODS: Thirty-eight patients with coronary artery disease were retrospectively enrolled. These patients had undergone stress perfusion single photon emission computed tomography (SPECT) and 123I-BMIPP SPECT in both the short-term (6.4 ± 4.7 months) and mid-term (29.9 ± 7.2 months) after isolated coronary artery bypass grafting. Tracer uptake was graded using a 17-segment, 5-point scoring model. Serial changes in SRS (summed rest score), SDS (summed difference score), the BMIPP score (total defect score of BMIPP), and the mismatch score (BMIPP score-SRS) were evaluated. In addition, persistent perfusion-metabolism mismatch (PM) was defined as mismatch score minus SDS of 3 or more during the mid-term postoperative period. The clinical parameters associated with PM were examined. RESULTS: From short- to mid-term postoperative period, the extent of infarcted myocardium (SRS) did not change significantly (7.8 ± 8.0 to 7.1 ± 7.0, P = 0.117). The extent of ischemic myocardium (SDS), the BMIPP score and the mismatch score, which reflects perfusion-metabolism mismatch, were significantly improved (2.0 ± 2.8 to 0.7 ± 1.0, P = 0.010; 12.2 ± 9.0 to 9.5 ± 7.9, P < 0.001; 4.4 ± 3.7 to 2.5 ± 2.6, P < 0.001; respectively). Remarkably, perfusion-metabolism mismatch persisted in 13 patients (34%) even in the mid-term postoperative period. eGFR and SYNTAX score were independent predictors of persistent perfusion-metabolic mismatch in multivariable analysis (OR = 0.951, 95% CI 0.898-0.985, P = 0.010 and OR = 1.126, 95% CI 1.011-1.254, P = 0.031, respectively). The mismatch score both in the short- and mid-term significantly correlated with SYNTAX score (r = 0.400 and r = 0.472, respectively). CONCLUSIONS: Fatty acid metabolism disturbance improved from short- to mid-term postoperative period in patients with successful reperfusion by coronary artery bypass grafting. However, in patients with severe atherosclerosis, impaired fatty acid metabolism was sustained until the mid-term postoperative period, even though ischemia had resolved.

Diagnostic utility and characteristics of CT-based attenuation correction in brain perfusion SPECT/CT in predicting the exacerbation of Alzheimer changes from mild cognitive impairment utilizing voxel-based statistical analysis in comparison with Chang's method.

OBJECTIVE: We examined the diagnostic value of brain perfusion single-photon emission computed tomography (SPECT) using voxel-based statistical analysis with CT-based attenuation correction (CT-AC) by comparing it to that with Chang's AC in mild cognitive impairment (MCI) patients and attempted to locate brain areas that are good indicators predicting the progression of MCI. METHODS: Twenty-six individuals matched for age, educational background and initial Mini-Mental State Examination (MMSE) score of more than 24 underwent SPECT with N-isopropyl-4-[123I]iodoamphetamine and were assigned to 2 groups: the stable MCI (S-MCI) group comprising 11 subjects who maintained their MMSE score (mean 27.0) during at least a 1-year follow-up period (mean 37.2 months) and the progressive MCI (P-MCI) group comprising 15 subjects whose MMSE scores decreased by 3 or more points (from 26.4 to 21.4, mean). The diagnostic values of the two AC methods for discriminating P-MCI from S-MCI were compared using voxel-based statistical analysis in the lobe (Level 2) and lobule/gyrus levels (Level 3). RESULTS: Receiver operating characteristic analysis revealed that the area under the curve (AUC) was higher with CT-AC than with Chang's AC in the left temporal and limbic lobes in Level 2. In Level 3, the AUC in the left middle temporal gyrus was higher with CT-AC (0.852) than with Chang's AC (0.827). There were differences between the gyri/lobules that showed higher AUCs with CT-AC and those that showed higher AUCs with Chang's AC. When the gyri with the 4 highest AUCs were combined, AUC (0.897) and accuracy (84.6%) were better with CT-AC than with Chang's AC (0.806 and 80.8%). Surprisingly, the AUCs in the posterior cingulate gyrus and precuneus, excluding the AUC in the right precuneus with Chang's AC (0.715), were no more than 0.70 and less useful. CONCLUSIONS: CT-AC may allow brain perfusion SPECT to reflect more exact neuropathic changes in MCI that would cause progression of early AD. CT-AC in conjunction with voxel-based statistical analysis could possess higher diagnostic accuracy for exacerbation of disease implying early Alzheimer changes in MCI patients, with decreases in cerebral perfusion in the left temporal and limbic lobes representing good indicators.

Feasibility of myocardial flow reserve prediction without the use of dynamic data from myocardial perfusion positron emission tomography.

Quantification of myocardial flow reserve (MFR) provides diagnostic value for detection of cardiovascular artery disease. However, the common calculation method for MFR requires dynamic acquisition and specific software. The study aimed to predict coronary artery disease by simpler calculation of myocardial count without the use of dynamic data from 13N-ammonia myocardial perfusion positron emission tomography (MP-PET). This study included 40 consecutive patients suspected of ischemic heart disease and 7 healthy controls (34 men and 13 women, 66 ± 12 years). All participants underwent adenosine stress and rest 13N-ammonia MP-PET. From the dynamic images, the MFR in the entire left ventricular myocardium (ELV) and the three-vessel area was calculated by dividing stress myocardial blood flow (MBF) by rest MBF. From the static images, the myocardium-to-background ratio (MBR) was calculated by dividing each area's counts/pixel by background counts in the upper thoracic aorta/pixel in both stress and rest images. The MBR-increasing rate (MBR-IR) was calculated by dividing stress MBR by rest MBR. The relationship between MFR and MBR-IR in each area was examined. The cutoff diagnostic value of MBR-IR corresponding to that of MFR for detection of cardiovascular artery disease was calculated. Each MBR-IR was closely correlated with each MFR (r = 0.830 in ELV, r = 0.864 in LAD, r = 0.829 in LCX, r = 0.757 in RCA). The cutoff values of MBR-IR were 1.45 in ELV, 1.46 in LAD, 1.41 in LCX, and 1.45 in RCA, respectively. This study demonstrated that quantification of MBR-IR may provide diagnostic value for detection of coronary artery disease as well as MFR.

Feasibility of combined risk stratification with coronary CT angiography and stress myocardial SPECT in patients with chronic coronary artery disease.

OBJECTIVE: To examine the additional prognostic value of coronary CT angiography (CTA) over myocardial perfusion imaging (MPI) in patients with suspected or known coronary artery disease. METHODS: A series of 157 patients (mean age 69 ± 9 years; 76% male; median follow-up 49 months; range 12-82 months) underwent stress MPI with SPECT and coronary CTA within a 6-month interval. Summed stress score (SSS) and summed difference score (SDS) of stress MPI, number of vessels with stenosis, and presence of left main trunk stenosis and high-risk plaques on coronary CTA were examined. Primary endpoints were cardiac death, acute myocardial infarction, or unstable angina requiring revascularization. Secondary endpoints were revascularization > 60 days after the latter imaging test. All patients were followed up for at least 1 year (mean 45 ± 19 months; range 12-82 months). RESULTS: Nine (6%) patients reached primary endpoints. Cardiac death occurred in 1 (0.6%) patient, myocardial infarction in 5 (3%), and unstable angina requiring hospitalization in 3 (2%). Elective revascularization within 60 days was performed in 31 (20%) patients. Sixteen (10%) patients required revascularization after > 60 days. Primary endpoint event-free survival rates were significantly lower in patients with myocardial ischemia (SDS ≥ 2) and high-risk plaques (HRP), and secondary endpoint event-free survival rates in patients with SSS ≥ 4 and 3VD. In multivariate analysis, Cox proportional hazards regression analysis revealed HRP (HR = 8.02; P = 0.006) and myocardial ischemia (HR = 11.487; P = 0.025) were significant predictors of primary endpoints, and 3VD of secondary endpoints (HR = 4.981; P = 0.008). Combined ischemia and HRP resulted in the significant increase of the model Chi square in prediction of primary end points from ischemia or HRP alone (17.4 vs. 9.41; P = 0.005, 17.4 vs. 9.39; P = 0.005, respectively). CONCLUSION: Coronary CT angiography may provide additional prognostic information over MPI.

The high matrix acquisition technique for imaging of atherosclerotic plaque inflammation in fluorine-18 fluorodeoxyglucose positron emission tomography/computed tomography with time-of-flight: Phantom study.

BACKGROUND: Motion artifact and partial volume effect caused underestimation of coronary plaque inflammation. This study evaluated the high matrix acquisition technique using time-of-flight (TOF) positron emission tomography/computed tomography for imaging of atherosclerotic plaque inflammation with fluorine-18 fluorodeoxyglucose in small and moving phantoms. METHODS AND RESULTS: All images were reconstructed using a conventional algorithm without TOF (4 × 4 × 4 mm3 voxel size) and a high matrix algorithm with TOF (2 × 2 × 2 mm3 voxel size). Microsphere phantoms of 10, 7.9, 6.2, 5.0, and 4.0 mm diameters were acquired in 3-dimensional list-mode for 30 minutes. A heart phantom mimicking cardiac motion consisted of a hot spot simulating a plaque (φ 4 mm, φ 2 mm) on the outside of the left ventricle. In the microsphere and heart phantom study, visual discrimination, maximum activity, and target-to-background ratio using the high matrix algorithm with TOF were better than those using the conventional algorithm without TOF. CONCLUSION: The high matrix algorithm with TOF improves detection of small targets in phantoms.

Usefulness of Single Photon Emission Computed Tomography/Computed Tomography Fusion-Hybrid Imaging to Evaluate Coronary Artery Disorders in Patients with a History of Kawasaki Disease.

BACKGROUND: The coronary arterial lesions of Kawasaki disease are mainly dilative lesions, aneurysms, and stenotic lesions formed before, after, and between aneurysms; these lesions develop in multiple branches resulting in complex coronary hemodynamics. Diagnosis of myocardial ischemia and infarction and evaluation of the culprit coronary arteries and regions is critical to evaluating the treatment and prognosis of patients. This study used hybrid imaging, in which multidetector computed tomographic (CT) images for coronary CT angiography (CCTA) and stress myocardial perfusion single-photon emission CT (SPECT) images were fused. We investigated the diagnosis of blood vessels and regions responsible for myocardial ischemia and infarction in patients with complex coronary arterial lesions; in addition, we evaluated myocardial lesions that developed directly under giant coronary artery aneurysms. METHODS: The subjects were 17 patients with Kawasaki disease with multiple coronary arterial lesions (median age, 18.0 years; 16 male). Both CCTA using 64-row CT and adenosine-loading myocardial SPECT were performed. Three branches, the right coronary artery (RCA), left anterior descending branch (LAD), and left circumflex branch, were evaluated with the conventional side-by-side interpretation, in which the images were lined up for diagnosis, and hybrid imaging, in which the CCTA and SPECT images were fused with computer processing. In addition, the myocardial lesions directly under giant coronary artery aneurysms were investigated with fusion imaging. RESULTS: Images sufficient for evaluation were acquired in all 17 patients. In the RCA, coronary arterial lesions were detected with CCTA in 16 patients. The evaluations were consistent between the side-by-side and fusion interpretation in 14 patients, and the blood vessel responsible for the myocardial ischemic region was identified in 2 patients. In the left circumflex branch, coronary arterial lesions were confirmed with 3-dimensional CT in 5 patients, and the the culprit coronary arteries for myocardial ischemia/infarction were confirmed with the fusion interpretation but not with the side-by-side interpretation. In the LAD, coronary arterial lesions were present in all patients, and the diagnosis was made with the fusion interpretation in 10 patients. In the LAD, small-range infarct lesions were detected directly under the giant coronary artery aneurysm in 8 patients, but were not confirmed with the side-by-side interpretation. CONCLUSION: Fusion imaging was capable of accurately evaluating myocardial ischemia/infarction as cardiovascular sequelae of Kawasaki disease and confirming the culprit coronary arteries. In addition, analysis of fusion images confirmed that small-range infarct lesions were concomitantly present directly under giant coronary artery aneurysms in the anterior descending coronary artery.

Patients with reduced heart rate response to adenosine infusion have low myocardial flow reserve in (13)N-ammonia PET studies.

To assess the effect of adenosine infusion by evaluating the relationship between heart rate (HR) response to adenosine and myocardial flow reserve (MFR) of remote regions supplied by normal coronary arteries in (13)N-ammonia PET. Thirty-one consecutive subjects (20 known coronary artery disease patients, 4 chronic heart failure patients, and 7 normal volunteers) except cases having 3-vessel disease underwent rest and adenosine stress (13)N-ammonia myocardial perfusion PET. Semi-quantitative, quantitative, and gated analyses were performed. Subjects were divided into two groups with regard to HR response to adenosine. Twenty-two subjects had normal HR response (peak/rest HR > 1.20), while reduced HR response (≤ 1.20) was observed in nine subjects. There were no differences in rest myocardial blood flow (MBF) of remote regions between the groups. Subjects with reduced HR response had significantly lower stress MBF and MFR of remote regions than those with normal HR response (stress MBF: 1.559 ± 0.517 vs. 2.279 ± 0.530, p = 0.004, MFR: 1.59 ± 0.36 vs. 2.35 ± 0.53, p = 0.001). There were no significant differences between the groups by means of semi-quantitative scoring. Rest and stress ejection fraction (EF) in the reduced HR response group was lower than that in the normal HR response group. In a multiple stepwise regression analysis, HR ratio, dyslipidemia, and Brinkman index were identified as predictors of the change in MFR of remote regions. Subjects with reduced HR response to adenosine had lower stress MBF and MFR of remote regions and lower EF. Moreover, HR response was one of the predictors of the change in MFR of remote regions.

Interpretative variability and its impact on the prognostic value of myocardial fatty acid imaging in asymptomatic hemodialysis patients in a multicenter trial in Japan.

BACKGROUND: The severity of impaired fatty acid utilization in the myocardium can predict cardiac death in asymptomatic patients on hemodialysis. However, interpretive variability and its impact on the prognostic value of myocardial fatty acid imaging are unknown. METHODS AND RESULTS: A total of 677 patients who received hemodialysis for ≥ 20 years and had one or more cardiovascular risk factors underwent (123)I-labeled ß-methyl iodophenyl-pentadecanoic acid (BMIPP) single-photon emission computed tomography (SPECT) at 48 hospitals across Japan. SPECT images were interpreted by experts at the nuclear core laboratory and by readers with varying skill levels at clinical centers, based on the standard 17-segment model and 5-point scoring systems, independently. The κ values only reached fair agreement both for overall impression (κ=0.298, normal vs. abnormal) and for categorical impression (κ=0.244, normal vs. mildly abnormal vs. severely abnormal). The normalcy rate was lower in readers at the clinical centers (60.9%) than in experts (69.9%). In contrast to the results assessed by experts, a Kaplan-Meier analysis based on the interpretation by readers at the clinical centers failed to distinguish the risk of events in patients with normal scans from that of patients with mildly abnormal scans. CONCLUSIONS: Considerable variability and its impact on prognostic value were observed in the visual interpretation of BMIPP SPECT images between experts and readers at the clinical centers.