Yoshimitsu Fukushima

Significant suppression of myocardial 18F-fluorodeoxyglucose uptake using 24-h carbohydrate restriction and a low-carbohydrate, high-fat diet

OBJECTIVES (18)F-fluorodeoxyglucose (FDG) positron emission tomography (PET)/computed tomography (CT) is a useful tool for evaluating inflammation. Because, myocardial-FDG uptake occurs with diverse physiology, it should be suppressed during evaluation of myocardial inflammation by FDG-PET/CT. Diets inducing fat-based metabolism, such as a low-carbohydrate, high-fat diet (LCHF), are used in uptake-suppression protocols. However, a complete suppression of myocardial-FDG uptake has not been established. Hence, we assessed the efficacy of 24-h carbohydrate restriction along with an LCHF diet compared to that of the conventional protocol in suppressing myocardial-FDG uptake and also compared fat and glucose metabolism between these protocols. METHODS Fourteen healthy volunteers agreed to undergo >24-h carbohydrate restriction (glucose, <10g) and drank an LCHF beverage an hour before FDG administration. A scan performed under conventional fasting protocol served as the control. The maximal standardized uptake values (SUVmax) of the left ventricular (LV) myocardium, and left atrium lumen (blood pool), liver, and lung fields as background, were measured. Blood sugar, free fatty acids (FFAs), insulin, and triglyceride concentrations were measured just before FDG injection and compared between the 2 protocols. RESULTS Global LV myocardial uptake was significantly lower with the diet-preparation protocol (SUVmax 1.31 [1.15-1.49] vs. 2.98 [1.76-6.43], p=0.001). Target-to-background ratios [myocardium-to-blood ratio (MBR), myocardium-to-lung ratio (MLR), and myocardium-to-liver ratio (MLvR)] were also significantly lower with the diet-preparation protocol [MBR: 0.75 (0.68-0.84) vs. 1.63 (0.98-4.09), p<0.001; MLR: 1.87 (1.53-2.47) vs. 4.54 (2.53-12.78), p=0.004; MLvR: 0.48 (0.44-0.56) vs. 1.11 (0.63-2.32), p=0.002]. Only insulin levels were significantly different between the subjects in each protocol group (11.3 [6.2-15.1] vs. 3.9 [2.9-6.2]). CONCLUSION Carbohydrate restriction together with an LCHF supplement administered 1h before FDG significantly suppressed myocardial-FDG uptake. FFAs and insulin might not directly affect myocardial-FDG uptake.

Assessment of myocardial washout of Tc-99m-sestamibi in patients with chronic heart failure: Comparison with normal control

BackgroundIn contrast to201T1C1,99mTc-sestamibi shows very slow myocardial clearance after its initial myocardial uptake. In the present study, myocardial washout of99mTc-sestamibi was calculated in patients with non-ischemic chronic heart failure (CHF) and compared with biventricular parameters obtained from first-pass and ECG-gated myocardial perfusion SPECT data.Methods and ResultsAfter administration of99mTc-sestamibi, 25 patients with CHF and 8 normal controls (NC) were examined by ECG-gated myocardial perfusion SPECT and planar data acquisition in the early and delayed (interval of 3 hours) phase. Left ventricular ejection fraction (LVEF, %), peak filling rate (PFR, sec−1), end-diastolic volume (LVEDV, ml) and end-systolic volume (LVESV, ml) were automatically calculated from the ECG-gated SPECT data. Myocardial washout rates over 3 hours were calculated from the early and delayed planar images. Myocardial washout rates in the CHF group (39.6±5.2%) were significantly higher than those in the NC group (31.2±5.5%, p<0.01). The myocardial washout rates for the 33 subjects showed significant correlations with LVEF (r=−0.61, p<0.001), PFR (r=−0.47, p<0.01), LVEDV (r=0.45, p<0.01) and LVESV (r=48, p<0.01),Conclusion: The myocardial washout rate of99mTc-sestamibi is considered to be a novel marker for the diagnosis of myocardial damage in patients with chronic heart failure.

Usefulness of 201TlCl/123I-BMIPP dual-myocardial SPECT for patients with non-ST segment elevation myocardial infarction

ObjectiveEarlier studies suggested that elevated cardiac troponin T (cTnT) might be useful for detecting less severe types of myocardial injury (i.e., non-ST segment elevation myocardial infarction). The objective of this study is to elucidate the usefulness of 201thallous chloride (201TlCl) and 123I-betamethyl-p-iodophenyl-pentadecanoic acid (123I-BMIPP) dual-single-photon emission computed tomography (SPECT) imaging for patients with myocardial infarction (MI) without ST segment elevation.MethodsConsecutive 86 patients (56 men and 30 women; mean age 66 ± 12 years) clinically diagnosed with acute myocardial infarction (AMI) were divided into two groups according to serum creatine kinase MB (CK-MB) and cTnT levels. Group A consisted of 53 patients with increased serum CK-MB and cTnT levels, and Group B, 33 patients with increased serum cTnT without increased serum CK-MB. All patients underwent 201TlCl and 123I-BMIPP dual-SPECT about 8 days following the onset. The left ventricular myocardium was divided into 20 segments on each SPECT image, and tracer accumulation in those segments was scored on a five-point scoring system. The total defect scores (TDS) were calculated by summing the scores for all 20 segments, and compared between groups A and B. Group B patients were subdivided into two groups according to the TDS on 123I-BMIPP images as groups BS (severe; TDS ≥ 8) and BM (mild; TDS ≤ 7), and we compared the prognosis over a period of 2 years from the onset between the three groups.ResultsThe TDS of group A derived from 201TlCl and 123I-BMIPP images was significantly higher than those of group B (14.5 ± 10.8 vs. 1.5 ± 2.4 and 20.8 ± 13.3 vs. 9.1 ± 6.2, respectively; P < 0.0001). The sensitivities of 201TlCl and 123I-BMIPP images were 94.3% (50/53) and 96.2% (51/53) to detect the culprit coronary lesions in group A (no significant difference). In contrast, the sensitivity of 123I-BMIPP images (72.7%, 24/33) was higher than that of 201TlCl images (27.3%, 9/33) in group B (P < 0.05). At 2 years of follow-up, the incidence of hard cardiac events in groups A, BS, and BM was 24.5%, 27.8%, and 6.7%, respectively. The rate of group BS, as well as that of group A, was significantly higher than that of group BM (P < 0.05).ConclusionsOf those with a clinical diagnosis of AMI accompanied by increased cTnT, the CK-MB negative patients accounted for 38% (33/86) of all patients as having non-ST segment elevation myocardial infarction such as NTMI. For such patients, 123I-BMIPP imaging is useful not only for the detection of the culprit lesions but also for the prediction of the prognosis.

Estimating Lymphodynamic Conditions and Lymphovenous Anastomosis Efficacy Using 99mTc-phytate Lymphoscintigraphy with SPECT-CT in Patients with Lower-limb Lymphedema

Background: Diagnostic and therapeutic strategies for lower-limb lymphedema have not yet been established. The purpose of this study was to estimate the lymphodynamic condition and therapeutic efficacy of lymphovenous anastomosis (LVA) in lower-limb lymphedema patients using 2-phase 99mTc-phytate lymphoscintigraphy with single-photon emission computed tomography-computed tomography (SPECT-CT). Methods: In this study, consecutive patients with lower-limb lymphedema who underwent 2-phase lymphoscintigraphy using 99mTc-phytate were enrolled between June 2013 and June 2014. SPECT-CT was also performed to clarify the relationships between functional and morphological information. In both the early and delayed images, inguinal lymph node accumulation, dermal backflow, and their sequential alternations were evaluated, and liver-to-blood ratio and inguinal lymph node-to-blood ratio were calculated. All participants were classified into 6 types of lymphodynamic conditions based on the image findings. Patients with both dermal backflow and associated normal lymphatic vessel accumulation proceeded to LVA and underwent a second lymphoscintigraphy after the operation. Results: Of all 30 participants, the largest population was categorized as type 4, which had consistent inguinal lymph node accumulation defect with dermal backflow. In 12 operated cases, dermal backflow was degraded in 10 cases by LVA. Liver-to-blood ratio in both early and delayed images and inguinal lymph node-to-blood ratio in delayed image significantly increased after LVA. Conclusions: Lymphoscintigraphy with SPECT-CT can provide both functional and morphological information simultaneously in patients with lower-limb lymphedema. Using these procedures, a type categorization for the patients was devised, which reflects their lymphodynamic conditions. The therapeutic efficacy of LVA could also be estimated quantitatively by the derived findings.

Prediction of Limb Salvage after Therapeutic Angiogenesis by Autologous Bone Marrow Cell Implantation in Patients with Critical Limb Ischemia

PURPOSE Despite advances in therapeutic angiogenesis by bone marrow cell implantation (BMCI), limb amputation remains a major unfavorable outcome in patients with critical limb ischemia (CLI). We sought to identify predictor(s) of limb salvage in CLI patients who received BMCI. MATERIALS AND METHODS Nineteen patients with CLI who treated by BMCI were divided into two groups; four patients with above-the-ankle amputation by 12 weeks after BMCI (amputation group) and the remaining 15 patients without (salvage group). We performed several blood-flow examinations before BMCI. Ankle-brachial index (ABI) was measured with the standard method. Transcutaneous oxygen tension (TcPO2) was measured at the dorsum of the foot, in the absence (baseline) and presence (maximum TcPO2) of oxygen inhalation. (99m)technetium-tetrofosmin ((99m)Tc-TF) perfusion index was determined at the foot and lower leg as the ratio of brain. RESULTS Maximum TcPO2 (p = 0.031) and (99m)Tc-TF perfusion index in the foot (p = 0.0068) was significantly higher in the salvage group than in the amputation group. Receiver operating characteristic (ROC) curve analysis identified maximum TcPO2 and (99m)Tc-TF perfusion index in the foot as having high predictive accuracy for limb salvage. CONCLUSION Maximum TcPO2 and (99m)Tc-TF perfusion index in the foot are promising predictors of limb salvage after BMCI in CLI.

Assessment of left ventricular function using solid-state gamma camera equipped with a highly-sensitive collimator

Purpose: The solid-state gamma camera 2020tc ImagerTM (Digirad, CA) is now commercially available and has been clinically applied. The present study evaluates the feasibility of equilibrium radionuclide ventriculography (ERNV) within a 3 min period using this camera equipped with a highly sensitive collimator.Materials and Methods: ERNV was performed from the best septal position (left anterior oblique view) in 20 patients with cardiac disease using a single detector angertype gamma camera equipped with a low-energy, high-resolution collimator. Immediately thereafter, we performed a second ERNV using the solid-state gamma camera equipped with a highly sensitive collimator. Acquisition periods were 10 and 3 min, respectively.Results: Significantly more counts were collected from over the left ventricle with the solid-state gamma camera over 3 min than those with the anger-type gamma camera over 10 min (817.1±387.8 k counts vs. 668.2±327.4 k counts, p<0.01). The left ventricular ejection fraction obtained from ERNV data using the solid-state gamma camera correlated closely with those acquired by the anger-type gamma camera (r=0.94, p<0.0001, SEE=5.93%).Conclusion: The results showed that the solid-state gamma camera could assess left ventricular function with excellent data collection efficiency and high reliability.

Assessment of contractile response to dobutamine stress by means of ECG-gated myocardial SPECT: Comparison with myocardial perfusion and fatty acid metabolism

The present study assessed left ventricular performance during dobutamine stress measured using gated SPECT, and compared the results to myocardial perfusion and fatty acid metabolism.MethodsThirty-six patients with myocardial infarction given99mTc-sestamibi or99mTc-tetrofosmin were examined by gated SPECT at rest and during dobutamine stress (4-20 µg • kg-1 • min-1). After acquiring data at the highest dose,201T1C1 was injected and dual-isotope SPECT was performed to assess myocardial ischemia. Thirty of 36 patients also underwent myocardial SPECT with123I-BMIPP. Regional wall motion changes during dobutamine infusion were determined from the gated SPECT data and classified as: (1) Improvement, (2) Worsening, (3) No change, and (4) Biphasic response. For myocardial segments of each infarct area, stress201Tl, rest99mTc and123I-BMIPP uptakes were graded on a five-point scoring system of defects from 0 (normal) to 4 (grossly defective).ResultsRest99mTc defect score index (DSI) in No change area was significantly higher than that in Biphasic area. The ΔDSI (stress201T1 – rest99mTc) in Biphasic area was significantly higher than those in Improvement and No change areas. The ΔDSI (BMIPP –99mTc) in Worsening area tended to be higher than that in No Change area.ConclusionsRegional contractile response to dobutamine stress analyzed by gated SPECT showed that the response in-myocardial infarct areas could be classified by rest and stress myocardial perfusion and BMIPP accumulation.

Serial assessment of left ventricular performance at rest and during bicycle exercise by ECG-gated myocardial perfusion SPECT.

The present study evaluates left ventricular performance during exercise by ECG-gated myocardial perfusion SPECT with short-time data collection. Methods: The study population consisted of 10 healthy volunteers (Group N) and 9 patients with ischemic heart disease (Group I). Seven patients in Group I had a history of prior myocardial infarction. Rest ECG-gated SPECT was performed 40 min after an injection of Tc-99m-tetrofosmin (555–740 MBq). After resting data acquisition, Group N underwent up to two 5-min stages of exercise (75 and 125 watts) on a detachable bicycle ergometer. The Group I patients all underwent symptom-limited, maximal testing on the ergometer. ECG-gated SPECT data were acquired from both groups for 3 min at rest and during the last 3 min of each exercise stage. Results: Significant increases occurred in LVEF from rest to peak stress in both groups (from 55.4±5.8 to 66.6±4.1% in group N, p<0.0001; from 49.0±12.8 to 56.7±13.8% in Group I, p<0.001). The LVESV values significantly decreased to peak stress in Group N (from 49.9±13.1 to 37.8±10.0 ml, p<0.0001), whereas LVEDV did not change (from 110.6±18.9 to 112.0±19.0 ml). In contrast, the LVESV values at rest and under peak stress were similar in Group I (from 52.6±23.9 to 51.7±31.4 ml) and LVEDV in Group I at peak exercise tended to increase (from 102.8±36.7 to 111.3±39.0 ml). The changes in LVESV from rest to peak stress were significantly different between Groups N and I (−12.1±6.3 vs.−0.9±11.6 ml, p<0.02). Conclusion: ECG-gated SPECT with short-time data collection can assess left ventricular function during exercise and may offer useful information for evaluating patients with ischemic heart disease.

Pseudonormal Corticomedullary Differentiation of the Kidney Assessed on T1-weighted Imaging for Chronic Kidney Disease Patients with Cirrhosis

PURPOSE We investigated whether corticomedullary differentiation (CMD) increased to a pseudonormal appearance on T1-weighted magnetic resonance (MR) images in patients with chronic kidney disease (CKD) with cirrhosis compared with patients with CKD without chronic liver disease. METHODS We assessed CMD on T1-weighted MR images of 32 patients with CKD with liver cirrhosis and 32 age-matched patients with CKD without liver cirrhosis, grading CMD visualization as good, moderate, or poor. We calculated quantitative CMD by the ratio of the signal intensity of the cortex to that of the medulla. RESULTS The proportions of patients in each of the good, moderate, and poor groups differed significantly between those with and without liver cirrhosis (P = 0.048). In patients with CKD with liver cirrhosis, the estimated glomerular filtration rate (eGFR) differed between those with poor CMD and those with good or moderate CMD (P < 0.01) but not between those with good and those with moderate CMD. In patients with CKD without cirrhosis, the eGFR differed significantly among the good, moderate, and poor CMD groups (P < 0.05). We observed no significant correlation between CMD and eGFR in patients with and without cirrhosis (P < 0.05, r = 0.62). CONCLUSION CMD of the kidney had a pseudonormal appearance on T1-weighted MR imaging in patients with CKD with cirrhosis.

4D Flow MR Imaging of Ophthalmic Artery Flow in Patients with Internal Carotid Artery Stenosis

Background and Purpose: To assess the clinical feasibility of time-resolved 3D phase contrast (4D Flow) MRI assessment of the ophthalmic artery (OphA) flow in patients with internal carotid artery stenosis (ICS). Materials and Methods: Twenty-one consecutive patients with unilateral ICS were recruited. 4D Flow MRI and acetazolamide-stress brain perfusion single photon emission computed tomography (SPECT) were performed. The flow direction on the affected-side OphA was categorized into native flow (anterograde or unclear) and non-native flow (retrograde flow) based on 4D Flow MRI. In the affected-side middle cerebral artery (MCA) territory, the ratio of rest cerebral blood flow to normal control (RCBFMCA) and cerebral vascular reserve (CVRMCA) were calculated from SPECT dataset. High-risk patients were defined based on the previous large cohort study (RCBFMCA < 80% and CVRMCA < 10%). Results: Eleven patients had native OphA flow (4 anterograde, 7 unclear) and the remaining 10 had non-native OphA flow. RCBFMCA and CVRMCA each were significantly lower in non-native flow group (84.9 ± 18.9% vs. 69.8 ± 7.3%, P < 0.05; 36.4 ± 20.6% vs. 17.0 ± 15.0%, P < 0.05). Four patients in the non-native flow group and none in the native flow group were confirmed as high-risk (Sensitivity/Specificity, 1.00/0.65). Conclusion: The 6 min standard 4D Flow MRI assessment of OphA in patients with ICS can predict intracranial hemodynamic impairment.