Fumi Sakamoto

Prediction of left main or 3-vessel disease using myocardial perfusion reserve on dynamic thallium-201 single-photon emission computed tomography with a semiconductor gamma camera

BACKGROUND Myocardial perfusion imaging (MPI) may fail to detect balanced ischemia. We evaluated myocardial perfusion reserve (MPR) using Tl dynamic single-photon emission computed tomography (SPECT) and a novel cadmium zinc telluride (CZT) camera for predicting 3-vessel or left main coronary artery disease (CAD). METHODS AND RESULTS: A total of 55 consecutive patients with suspected CAD underwent SPECT-MPI and coronary angiography. The MPR index was calculated using the standard 2-compartment kinetic model. We analyzed the utility of MPR index, other SPECT findings, and various clinical variables. On multivariate analysis, MPR index and history of previous myocardial infarction (MI) predicted left main and 3-vessel disease. The area under the receiver operating characteristic curve was 0.81 for MPR index, 0.699 for history of previous MI, and 0.86 for MPR index plus history of previous MI. MPR index ≤1.5 yielded the highest diagnostic accuracy. Sensitivity, specificity, and accuracy were 86%, 78%, and 80%, respectively, for MPR index, 64%, 76%, 73% for previous MI, and 57%, 93%, and 84% for MPR index plus history of previous MI. CONCLUSIONS Quantification of MPR using dynamic SPECT and a novel CZT camera may identify balanced ischemia in patients with left main or 3-vessel disease.

Prevalence and Topography of Small Hypointense Foci Suggesting Microbleeds on 3T Susceptibility-Weighted Imaging in Various Types of Dementia

BACKGROUND AND PURPOSE: The prevalence and topography of small hypointense foci suggesting microbleeds on 3T SWI in various types of dementia have not been systematically investigated. The purpose of this study was to determine the prevalence and topography of SHF on 3T SWI in patients with different dementia subtypes. MATERIALS AND METHODS: We included 347 consecutive patients (217 women, 130 men; age range, 42–93 years; mean age, 74 years) who attended our memory clinic and underwent 3T SWI. They were divided into 6 groups: subjective complaints, MCI, AD, DLB, VaD, and FTLD. Two neuroradiologists evaluated the number and location of SHF on SWIs. Statistical analyses were performed to evaluate inter- and intragroup differences. RESULTS: Of the 347 patients, 160 (46.1%) exhibited at least 1 small hypointense focus. This was true in 86% with VaD, 54% with DLB, 48% with AD, 41% with MCI, 27% with FTLD, and 22% with subjective complaints. With the subjective complaints group as a reference, the odds ratio adjusted by age, sex, and arterial hypertension was 9.2 (95% CI, 2.0–43.6) for VaD; 5.4 (95% CI, 1.2–24.3) for AD; 3.1 for DLB (95% CI, 1.1–8.8); 2.0 for MCI (95% CI, 0.5–8.1); and 1.5 for FTLD (95% CI, 0.4–5.4). There was a significant lobar predilection for AD, DLB, and FTLD groups (P < .05). CONCLUSIONS: On 3T SWI, patients with VaD, AD, and DLB manifested a high SHF prevalence. In patients with AD, DLB, and FTLD, the SHF exhibited a lobar predilection.

99m Tc-GSA SPECT/CT fused images for assessment of hepatic function and hepatectomy planning

To assure safe hepatectomy, accurate estimation of the functional reserve of the future remnant liver is crucial. The combination of indocyanine green retention rate at 15 min and CT volumetry is widely used in deciding on the extent of hepatectomy. On the other hand, there are quantitative indices calculated from (99m)Tc-GSA scintigraphy that reflect the number and function of hepatocytes. Therefore, there are many indices calculated from (99m)Tc-GSA scintigraphy that have been reported. In recent Annals of Surgical Oncology on Oct. 2014 the Uptake Index (UI) calculated from (99m)Tc-GSA scintigraphy was reported to be useful for hepatectomy planning and postoperative liver failure prediction. In this paper, we report on the usefulness and limits of quantitative indices calculated from (99m)Tc-GSA SPECT/CT for preoperative simulation.

123I-MIBG myocardial scintigraphy for the evaluation of Lewy body disease: are delayed images essential? Is visual assessment useful?

OBJECTIVE: We performed 123I-meta-iodobenzylguanidine (123I-MIBG) myocardial scintigraphy for the diagnosis of Lewy body disease (LBD) and assessed whether the early heart-to-mediastinum (H/M) ratio was diagnostic and whether visual image analysis was useful. METHODS: Our study included 453 patients with clinically suspected LBD who had undergone 123I-MIBG myocardial scintigraphy. We evaluated semi-quantitative values (early and delayed H/M ratio, washout rate) and performed visual image analysis. The sensitivity, specificity, accuracy, positive-predictive value (PPV) and negative-predictive value (NPV) of both analyses were calculated. RESULTS: The early H/M ratio exhibited the best diagnostic ability. Its overall sensitivity, specificity, accuracy, PPV and NPV were 72.2%, 93.1%, 84.3%, 88.5% and 82.2%, respectively (cut-off value 2.2 or less). However, there was no significant difference from the delayed H/M ratio or the results of visual assessment. CONCLUSION: 123I-MIBG myocardial scintigraphy accurately differentiates between patients with and without LBD and a correct diagnosis can be established based on the early H/M ratio. We also document that visual evaluation of scintigrams is useful. Therefore, patients may benefit from the single performance of the procedure because a correct diagnosis can be obtained early in the disease process and their prognosis and appropriate treatment can be determined. ADVANCES IN KNOWLEDGE: 123I-MIBG myocardial scintigraphy on the early H/M ratio makes it possible to differentiate between patients with LBD and patients without LBD.

Diagnosis of dementia with Lewy bodies: Can 123I-IMP and 123I-MIBG scintigraphy yield new core features?

OBJECTIVE Since the clinical symptoms of different types of dementia frequently overlap, especially in the earlier stages at onset, it is difficult to distinguish dementia with Lewy bodies (DLB) from other neurodegenerative dementias based on their clinical manifestations alone. Nuclear medicine imaging has been reported as a high-value index for the objective evaluation and diagnosis of DLB. The aim of this study was to evaluate whether nuclear medicine imaging findings may yield core features to be added to the diagnosis of DLB. METHODS We enrolled 332 patients with suspected DLB. All were evaluated by both 123I-metaiodobenzylguanidine (123I-MIBG) myocardial scintigraphy and 123I-labelled N-isopropyl-p-iodoamphetamine (123I-IMP). brain perfusion single-photon emission CT. The final clinical diagnosis indicated probable DLB in 92 patients (40 males, 52 females; mean age ± standard deviation, 77.4 ± 6.4 years; range, 56-89 years); 240 patients (98 males, 142 females; mean age, 75.5 ± 9.0 years; range, 70-87 years) were recorded as being without DLB. The accepted core features used for clinical evaluations were fluctuating cognition, visual hallucinations and Parkinsonism. The nuclear medicine evaluation indices were the severity score of cerebral blood flow on 123I-IMP scintigraphs of the posterior cingulate and praecuneus and a reduction in the blood flow in the occipital lobe. For 123I-MIBG evaluation, we recorded the early and delayed heart-to-mediastinum (H/M) ratios and the washout rate. RESULTS Univariate and multivariate analyses of fluctuating cognition, visual hallucinations, Parkinsonism and early H/M ratio in patients with probable and without DLB revealed significant differences. Parameters based on 123I-IMP studies did not show any significant differences by multivariate analysis. The area under the curve for the early H/M ratio was 0.918; for fluctuating cognition, visual hallucinations and Parkinsonism, it was 0.693, 0.760 and 0.611, respectively, by receiver-operating characteristic analysis. The early H/M ratio of <2.0 on 123I-MIBG scintigraphs was of the highest diagnostic accuracy. The sensitivity, specificity and accuracy for the diagnosis of probable DLB were 82.4%, 96.3% and 92.5%, respectively. CONCLUSION The early H/M ratio obtained by 123I-MIBG myocardial scintigraphy can serve as a reliable diagnostic index for the core clinical features of DLB. It can be used for the early diagnosis and treatment of DLB. Advances in knowledge: 123I-MIBG myocardial scintigraphy performed at the initial clinical examination can facilitate the early identification or exclusion of DLB and the early H/M ratio may be a diagnostic biomarker for DLB.

Measuring hepatic functional reserve using T1 mapping of Gd-EOB-DTPA enhanced 3T MR imaging: A preliminary study comparing with 99mTc GSA scintigraphy and signal intensity based parameters

PURPOSE To determine the utility of liver T1-mapping on gadolinium-ethoxybenzyl-diethylenetriamine-pentaacetic acid (Gd-EOB-DTPA) enhanced magnetic resonance (MR) imaging for the measurement of liver functional reserve compared with the signal intensity (SI) based parameters, technetium-99m-galactosyl serum albumin (99mTc-GSA) scintigraphy and indocyanine green (ICG) clearance. MATERIALS AND METHODS This retrospective study included 111 patients (Child-Pugh-A 90; -B 21) performed with both Gd-EOB-DTPA enhanced liver MR imaging and 99mTc-GSA (76 patients with ICG). Receiver operating characteristic (ROC) curve analysis was performed to compare diagnostic performances of T1-relaxation-time parameters [pre-(T1pre) and post-contrast (T1hb) Gd-EOB-DTPA], SI based parameters [relative enhancement (RE), liver-to-muscle-ratio (LMR), liver-to-spleen-ratio (LSR)] and 99mTc-GSA scintigraphy blood clearance index (HH15)] for Child-Pugh classification. Pearsons correlation was used for comparisons among T1-relaxation-time parameters, SI-based parameters, HH15 and ICG. RESULTS A significant difference was obtained for Child-Pugh classification with T1hb, ΔT1, all SI based parameters and HH15. T1hb had the highest AUC followed by RE, LMR, LSR, ΔT1, HH15 and T1pre. The correlation coefficients with HH15 were T1pre 0.22, T1hb 0.53, ΔT1 -0.38 of T1 relaxation parameters; RE -0.44, LMR -0.45, LSR -0.43 of SI-based parameters. T1hb was highest for correlation with HH15. The correlation coefficients with ICG were T1pre 0.29, T1hb 0.64, ΔT1 -0.42 of T1 relaxation parameters; RE -0.50, LMR -0.61, LSR -0.58 of SI-based parameters; 0.64 of HH15. Both T1hb and HH15 were highest for correlation with ICG. CONCLUSION T1 relaxation time at post-contrast of Gd-EOB-DTPA (T1hb) was strongly correlated with ICG clearance and moderately correlated HH15 with 99mTc-GSA. T1hb has the potential to provide robust parameter of liver functional reserve.

Quantification of myocardial perfusion reserve using dynamic SPECT images of patients with chronic kidney disease

BACKGROUND Chronic kidney disease (CKD) is an independent risk factor for cardiovascular disorders. The aim of this study was to examine whether the quantitatively measured myocardial blood flow (MBF) or myocardial perfusion reserve (MPR), calculated by dynamic single photon emission computed tomography (SPECT) analysis using a cardiac cadmium zinc telluride (CZT) gamma camera, was related to renal dysfunction in patients with normal myocardial perfusion imaging (MPI) findings. METHODS The study population consisted of 46 patients with CKD and 46 individuals without CKD (controls). Their MPR index was quantitatively measured using adenosine MPI with a cardiac CZT gamma camera. All assessments were with a single tissue compartment kinetic model. The K1 value was calculated on stress and at-rest images. To obtain the MPR index we divided K1 stress-by K1 at-rest values. RESULTS The at-rest K1 value was significantly higher and the MPR index was significantly lower in patients with CKD than those without CKD [CKD vs. CONTROLS at-rest K1 value, 0.21 (0.17-0.25) vs. 0.19 (0.16-0.22), p=0.040; MPR index, 1.86 (1.69-2.22) vs. 2.19 (1.93-2.41), p<0.001]. The stress K1 values were not significantly different. CONCLUSION The MPR index is significantly lower in CKD patients; this is considered as being mainly due to an increase in the at-rest K1 value.

Utility of Single-Photon Emission Computed Tomography/Computed Tomography Fusion Imaging With 99 m Tc-Pyrophosphate Scintigraphy in the Assessment of Cardiac Transthyretin Amyloidosis

tium-99 m-pyrophosphate (99 mTc-PYP) has been shown to have high diagnostic performance in the differentiation of cardiac ATTR from non-ATTR heart failure.2,3 A 52-year-old woman with heart failure was admitted to hospital. On 99 mTc-PYP scintigraphy to assess for cardiac C ardiac transthyretin amyloidosis (ATTR) is increasingly recognized as an important cause of heart failure with preserved ejection fraction, and a growing public health problem with an increasing prevalence.1 Cardiac uptake on bone scintigraphy with techne-

Quantitative index calculated by 99m Tc-GSA scintigraphy

(99m)Tc-galactosyl human serum albumin (GSA) scintigraphy is useful to evaluate hepatic function and hepatic functional reserve. A reliable SPECT and CT integrated system is now commercially available. Using this system, we can obtain (99m)Tc-GSA SPECT/CT fused imaging with a small registration error. Therefore, the (99m)Tc-GSA scintigraphy techniques prove more useful in clinical practice than have been previously reported. In the latest Annals of Surgical Oncology on Oct 2014, the uptake index (UI) values calculated from (99m)Tc-GSA scintigraphy are reported to be useful for predicting the functional reserve of the future remnant liver. In this paper, we describe the usefulness of (99m)Tc-GSA scintigraphy as well as some cautions that are necessary as regards using the system.