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Annals of Nuclear Medicine (v.23, #7)

¹¹C-acetate for positron emission tomography imaging of clinical stage IA lung adenocarcinoma: comparison with ¹⁸F-fluorodeoxyglucose for imaging and evaluation of tumor aggressiveness by Hidekatsu Shibata; Hiroaki Nomori; Kimiichi Uno; Ken-ichi Iyama; Katsumi Tomiyoshi; Rumi Nakashima; Kazuya Sakaguchi; Tomoyuki Goya; Iwao Takanami; Kiyoshi Koizumi; Takashi Suzuki; Masahiro Kaji; Hirotoshi Horio (pp. 609-616).

To determine the usefulness of positron emission tomography (PET) with ¹¹C-acetate (AC) for imaging lung adenocarcinoma and evaluating its tumor aggressiveness, AC- and ¹⁸F-fluorodeoxyglucose (FDG)-PET were compared.One hundred and sixty-nine adenocarcinomas with clinical stage IA and 53 benign nodules were examined by both AC- and FDG-PET before surgery. The sensitivity and specificity for discriminating benign/adenocarcinoma were compared between AC- and FDG-PET. The AC and FDG uptakes were examined to determine the relationship with tumor aggressiveness, i.e., pathological tumor stage, lymphatic, vascular, or pleural involvement, and proliferative activity determined by Ki-67 staining score.While the sensitivity of AC-PET was significantly higher than FDG-PET for bronchioloalveolar carcinoma (BAC) and well-differentiated (W/D) adenocarcinoma (p < 0.001 and 0.006, respectively), there was no significant difference for moderately or poorly differentiated adenocarcinoma. The specificity was not different between them. While FDG uptakes were significantly higher in tumors with pathological advanced stages or those with lymphatic, vascular and/or pleural involvements than in tumors with pathological stage IA or those without these tumor involvements (p = 0.04 to p < 0.001), AC uptake did not show significant differences between the respective sub-groups except according to the tumor stage. While both AC and FDG uptakes showed a significant correlation with Ki-67 staining scores (p = 0.03 and p < 0.001, respectively), the correlation coefficient of former was lower than that of latter (p = 0.07).While AC-PET can image BAC and W/D adenocarcinoma with a higher sensitivity than FDG-PET, it cannot evaluate tumor aggressiveness of clinical stage IA lung adenocarcinoma as well as FDG-PET.

Keywords: Positron emission tomography; Acetate; Fluorodeoxyglucose; Lung cancer; Adenocarcinoma

Improvement of image quality using interpolated projection data estimation method in SPECT by Akihiro Takaki; Tsutomu Soma; Akihiro Kojima; Kimie Asao; Shinya Kamada; Masanori Matsumoto; Kenya Murase (pp. 617-626).

General data acquisition for single photon emission computed tomography (SPECT) is performed in 90 or 60 directions, with a coarse pitch of approximately 4–6° for a rotation of 360° or 180°, using a gamma camera. No data between adjacent projections will be sampled under these circumstances. The aim of the study was to develop a method to improve SPECT image quality by generating lacking projection data through interpolation of data obtained with a coarse pitch such as 6°.The projection data set at each individual degree in 360 directions was generated by a weighted average interpolation method from the projection data acquired with a coarse sampling angle (interpolated projection data estimation processing method, IPDE method). The IPDE method was applied to the numerical digital phantom data, actual phantom data and clinical brain data with Tc-99m ECD. All SPECT images were reconstructed by the filtered back-projection method and compared with the original SPECT images.The results confirmed that streak artifacts decreased by apparently increasing a sampling number in SPECT after interpolation and also improved S/N ratio of the root mean square uncertainty value. Furthermore, the normalized mean square error values, compared with standard images, had similar ones after interpolation. Moreover, the contrast and concentration ratios increased their effects after interpolation.These results indicate that effective improvement of image quality can be expected with interpolation. Thus, image quality and the ability to depict images can be improved while maintaining the present acquisition time and image quality. In addition, this can be achieved more effectively than at present even if the acquisition time is reduced.

Keywords: SPECT; Projection data; Sampling number and pitch; Interpolation processing; Image quality

Evaluation of dynamic row-action maximum likelihood algorithm reconstruction for quantitative ¹⁵O brain PET by Masanobu Ibaraki; Kaoru Sato; Tetsuro Mizuta; Keishi Kitamura; Shuichi Miura; Shigeki Sugawara; Yuki Shinohara; Toshibumi Kinoshita (pp. 627-638).

A modified version of row-action maximum likelihood algorithm (RAMLA) using a ‘subset-dependent’ relaxation parameter for noise suppression, or dynamic RAMLA (DRAMA), has been proposed. The aim of this study was to assess the capability of DRAMA reconstruction for quantitative ¹⁵O brain positron emission tomography (PET).Seventeen healthy volunteers were studied using a 3D PET scanner. The PET study included 3 sequential PET scans for C¹⁵O, ¹⁵O₂ and H ₂ ¹⁵ O. First, the number of main iterations (N _it) in DRAMA was optimized in relation to image convergence and statistical image noise. To estimate the statistical variance of reconstructed images on a pixel-by-pixel basis, a sinogram bootstrap method was applied using list-mode PET data. Once the optimal N _it was determined, statistical image noise and quantitative parameters, i.e., cerebral blood flow (CBF), cerebral blood volume (CBV), cerebral metabolic rate of oxygen (CMRO₂) and oxygen extraction fraction (OEF) were compared between DRAMA and conventional FBP. DRAMA images were post-filtered so that their spatial resolutions were matched with FBP images with a 6-mm FWHM Gaussian filter.Based on the count recovery data, N _it = 3 was determined as an optimal parameter for ¹⁵O PET data. The sinogram bootstrap analysis revealed that DRAMA reconstruction resulted in less statistical noise, especially in a low-activity region compared to FBP. Agreement of quantitative values between FBP and DRAMA was excellent. For DRAMA images, average gray matter values of CBF, CBV, CMRO₂ and OEF were 46.1 ± 4.5 (mL/100 mL/min), 3.35 ± 0.40 (mL/100 mL), 3.42 ± 0.35 (mL/100 mL/min) and 42.1 ± 3.8 (%), respectively. These values were comparable to corresponding values with FBP images: 46.6 ± 4.6 (mL/100 mL/min), 3.34 ± 0.39 (mL/100 mL), 3.48 ± 0.34 (mL/100 mL/min) and 42.4 ± 3.8 (%), respectively.DRAMA reconstruction is applicable to quantitative ¹⁵O PET study and is superior to conventional FBP in terms of image quality.

Keywords: Iterative reconstruction; Dynamic RAMLA; CBF; Oxygen metabolism; ¹⁵O PET

Predictor of underlying myocardial damage in normally functioning left ventricle with narrow QRS complex: relationship between QRS duration at right ventricle pacing and iodine-123 metaiodobenzylguanidine myocardial scintigraphy by Naoyuki Sata; Tomonori Kawano; Naokazu Hamada; Takashi Horinouchi; Shigeru Amitani; Yukinori Moriyama; Kenkichi Miyahara (pp. 639-641).

Washout rate of iodine-123 metaiodobenzylguanidine (MIBG) myocardial scintigraphy is correlated with the degree of myocardial damage. The aim of this study is to ascertain whether there is any relationship between QRS complex duration at right ventricle (RV) pacing and the degree of myocardial damage assessed by I-123 MIBG myocardial scintigraphy in normally functioning left ventricle.The study included 22 patients (10 men and 12 women, ranging in age from 48 to 89 years), with atrioventricular (AV) block (n = 15) and sick sinus syndrome (n = 7). All patients had baseline QRS duration of less than 120 ms and received implantation of a DDD-mode permanent pacemaker. Iodine-123 MIBG myocardial scintigraphy was performed before the pacemaker implantation, and QRS duration at RV pacing at a rate of 70 ppm was calculated immediately after the implantation.With the use of RV pacing, QRS duration was prolonged ranging from 122.4 to 185.6 ms with a mean of 153.2 ± 15.2 ms. Washout rate of I-123 MIBG myocardial scintigraphy (WR) was calculated as ranging from 5.0 to 83.0% with a mean of 44.2 ± 17.5%. There was a strong correlation between WR and QRS duration at RV pacing (r = 0.735, p < 0.001).It was confirmed that WR of I-123 MIBG was correlated positively with QRS duration at RV pacing. Measurement of QRS duration may be helpful to evaluate the degree of underlying myocardial damage even in the normally functioning left ventricle.

Keywords: QRS complex; Iodine-123 metaiodobenzylguanidine myocardial scintigraphy; Right ventricle pacing

A bone marrow F-18 FDG uptake exceeding the liver uptake may indicate bone marrow hyperactivity by Kentaro Inoue; Ryoi Goto; Ken Okada; Shigeo Kinomura; Hiroshi Fukuda (pp. 643-649).

In clinical positron emission tomography (PET) studies for oncology, it is occasionally required to differentiate a diffuse increase in bone marrow (BM) F-18 fluoro-2-deoxyglucose (FDG) uptake due to the involvement of malignancy or hematopoietic disease and that due to the administration of hematopoietic cytokines, an inflammation reaction, or stimulation by some types of malignancy. The objectives of this study were to clarify the relationships between BM F-18 FDG uptake and blood parameters as well as age, and also to determine the degree of F-18 FDG accumulation that constitutes an abnormal level referring to blood parameters.Records of 65 patients, 32 with benign diseases and 33 with malignancies without metastasis in bone and liver until a half year after the PET examination, were analyzed retrospectively. Regions of interest were placed on the liver and the lower thoracic and lumbar vertebrae to measure the standardized uptake value (SUV), and vertebral SUVs were averaged as the BM SUV_mean. The BM SUV_mean was divided by the liver SUV to calculate the BM/liver ratio. The relationships among the BM SUV_mean, or BM/liver ratio, and blood parameters and age were tested using multiple regression analysis.In both patients with and without malignancy, a multiple regression model using the BM/liver ratio showed a higher coefficient of determination value than that using the BM SUV_mean, indicating that the correction by the liver SUV reduced the interindividual variation in the BM SUV_mean. The BM/liver ratio was negatively correlated with age (β = −0.41 and −0.43, respectively) and positively correlated with serum C-reactive protein (CRP) level (β = 0.39 and 0.46, respectively) in both groups of patients. Every patient with benign disease who had a ratio greater than or equal to 1 had an increased CRP level.The BM F-18 FDG uptake depends on the patient’s age and serum CRP level, both with and without malignancy. A BM F-18 FDG uptake greater than or equal to that of the liver may indicate BM activation.

Keywords: F-18 FDG; Bone marrow; Inflammation; C-reactive protein; Age

New quantitative method for bone tracer uptake of temporomandibular joint using Tc-99m MDP skull SPECT by Byeong-Cheol Ahn; Hae-Joo Kim; Sang-Woo Lee; Jeongsoo Yoo; Jae-Kap Choi; Jaetae Lee (pp. 651-656).

Quantitative bone SPECT studies have several advantages over qualitative studies for evaluating a temporomandibular joint (TMJ), yet in certain cases additional images are still needed. Accordingly, the current study developed a new easy SPECT quantification method for the bone tracer uptake in a TMJ and evaluated its usefulness and inter-observer variability in patients with TMJ pain.Sixty-six adult patients (11 males, 55 females) with a mean age of 31 years (range 22–79 years) suffering from TMJ pain were questioned regarding the history of their condition, and then subjected to an oromaxillofacial examination and bone SPECT. New quantitative data for TMJs (TMJ index) were calculated from a formula using TMJ and skull counts.TMJs with spontaneous pain had higher TMJ indices than those without spontaneous pain (8.87 vs. 6.87, P = 0.032). TMJs with mouth-opening pain or palpatory pain also exhibited higher TMJ indices than those without such pains, although the differences were not statistically significant. Positive TMJs, according to a visual SPECT interpretation, had much higher TMJ indices than the negative ones (8.99 vs. 5.37, P < 0.001). The reference skull count, mean TMJ count and TMJ index obtained using the proposed TMJ quantification method demonstrated an excellent correlation based on two independent observers (r = 0.996, r = 0.993 and r = 0.989, respectively; P < 0.001).The current results indicate that the proposed quantitative TMJ bone SPECT is easy to perform, plus the resulting TMJ index has a lower inter-observer variability, making it an effective TMJ evaluation method for patients with painful TMJs, and especially useful for serial studies.

Keywords: Temporomandibular joint; Bone SPECT; Quantification

Significance of chronic marked hyperglycemia on FDG-PET: is it really problematic for clinical oncologic imaging? by Tadashi Hara; Tatsuya Higashi; Yuji Nakamoto; Tsuyoshi Suga; Tsuneo Saga; Takayoshi Ishimori; Koichi Ishizu; Hidekazu Kawashima; Shigeto Kawase; Keiichi Matsumoto; Kaori Togashi (pp. 657-669).

The purpose of this study was to evaluate the adverse effects of chronic marked hyperglycemia on clinical diagnostic performance of positron emission tomography (PET) using ¹⁸F-fuorodeoxyglucose (FDG).Fifty-seven scans of 54 patients, who received FDG-PET for the diagnosis of various cancer(s), and who showed high plasma glucose level of more than 200 mg/dl at the time of administration of FDG in spite of at least 4-h fasting, were retrospectively analyzed. In the clinical follow-up, this high plasma glucose was confirmed as chronic hyperglycemia derived from uncontrolled diabetes (n = 32) and untreated diabetes (n = 25). Based on the final diagnosis of malignancy obtained by histopathology or clinical follow-up for at least 6 months, the diagnostic performance of visual PET analysis was evaluated.Excluding nine scans of nine patients without sufficient follow-up, final diagnosis was obtained in 48 scans of 45 patients. In 36 scans of 36 patients, at least one malignant lesion was finally confirmed, and true-positive and false-negative results were obtained in 30 and six cases, respectively. Six cases showed false-negative results due to low FDG-avid pathological characteristics (hepatocellular carcinoma, etc.), chemotherapeutic effect or small tumor size. Overall, the patient-based sensitivity, specificity, positive predictive value, negative predictive value and diagnostic accuracy were 83, 83, 94, 63 and 83%, respectively. In lesion-based diagnosis, 56 of 75 lesions (74%) were depicted by PET, while 19 lesions were negative on PET, also due to low FDG-avid characteristics or small size (less than 15 mm).At the time of chronic hyperglycemia (not acute hyperglycemia), the adverse effect caused by high plasma glucose level was minimum. The FDG uptake of the tumor maintained a sufficiently high level for visual clinical diagnosis in most cases, except in the cases of low FDG-avid tumors or small lesions (15 mm in size).

Keywords: FDG-PET; Hyperglycemia; Diabetes; False negative; Tumor

Diagnostic usefulness of ¹⁸F-FDG PET/CT in the differentiation of pulmonary artery sarcoma and pulmonary embolism by Kimiteru Ito; Kazuo Kubota; Miyako Morooka; Yoshitaka Shida; Kanehiro Hasuo; Hisako Endo; Hiroshi Matsuda (pp. 671-676).

The purpose of this study was to evaluate the usefulness of 18F-fluorodeoxyglucose (FDG) positron emission tomography (PET) in differentiating pulmonary artery sarcoma from pulmonary embolism.We evaluated three patients with pulmonary artery sarcoma and 10 patients with proximal pulmonary embolism (6 men and 7 women, ranging in age from 35 to 94 years). All the patients had evidence of perfusion defects in their proximal pulmonary arteries on contrast-enhanced computed tomography (CT) scans performed prior to PET/CT. The maximum standardized uptake value (SUV_max) of FDG uptake in all the lesions was measured using PET/CT. The location of lesions, background uptake or thrombi in the legs were evaluated in both groups as basic characteristics.The mean SUV_max of the pulmonary artery sarcomas (7.63 ± 2.21, n = 3) and the pulmonary embolisms (2.31 ± 0.41, n = 10) were significantly different (P < 0.05). The mean times between the initial contrast-enhanced CT scan and PET/CT scan were similar in both groups (P = 0.7804). The differences in the locations in lesions between the three groups (right, left and bilateral) or background uptakes were not significant.FDG PET/CT could distinguish pulmonary artery sarcoma from pulmonary embolism based on the SUV_max value.

Keywords: Pulmonary embolism; Pulmonary artery sarcoma (PAS); PET/CT; FDG

Predictive value of cardiac autonomic indexes and MIBG washout in ICD recipients with mild to moderate heart failure by Maria Koutelou; Athanasios Katsikis; Peny Flevari; George Theodorakis; Efthimios Livanis; Michalis Georgiadis; Vasilios Voudris; Dimitrios Kremastinos (pp. 677-684).

We aimed at evaluating the combined use of heart rate variability (HRV), baroreflex sensitivity (BRS), and MIBG imaging in the risk stratification for sudden cardiac death (SCD) of patients with mild to moderate heart failure.Twenty-five patients (17 male and 8 female, mean age 63 ± 5 years, mean LVEF 36 ± 3%) with a recently implanted defibrillator (ICD) and mild (NYHA I-II) heart failure due to either ischemic (n = 15) or dilated (n = 10) cardiomyopathy were studied. One week after ICD implantation they underwent (a) baroreflex sensitivity (BRS) evaluation to bolus phenylephrine by the Oxford method, (b) 24-h heart rate variability (HRV) assessment, and (c) MIBG imaging. The mean patient follow-up was 32 ± 10 months. Simple correlation and stepwise multiple regression analysis was performed to evaluate (a) if the number of sustained ventricular tachycardia (cycle length <330 ms) or fibrillation episodes per month is related to one or more of MIBG, BRS, and HRV indexes and (b) if MIBG % washout is related to HRV and/or BRS.The frequency of fast ventricular arrhythmic episodes (FVAE) demonstrated an inverse relation to BRS (p < 0.0001), rMSSD (p = 0.001), and pNN50 (p = 0.0034), while it was positively related to LF (p < 0.0001) and MIBG % washout (p = 0.001). BRS, LF, rMSSD, and MIBG washout were also independent predictors of FVAE. MIBG washout was related to only one HRV marker (SDNN-I, p < 0.0001), while no correlation was observed with BRS.In ICD recipients with well-compensated heart failure, autonomic markers derived from BRS, HRV, and MIBG studies are related to FVAE. These markers have limited inter-dependency and constitute useful means for SCD risk stratification in this subgroup of patients.

Keywords: HRV; BRS; MIBG; SCD; Heart failure

Cancer screening using ¹⁸F-FDG PET/CT in Korean asymptomatic volunteers: a preliminary report by Jeong Won Lee; Keon Wook Kang; Jin Chul Paeng; Sang Mi Lee; Su Jin Jang; June-Key Chung; Myung Chul Lee; Dong Soo Lee (pp. 685-691).

This study was performed to evaluate the clinical value of ¹⁸F-fluorodeoxyglucose (FDG) positron-emission tomography (PET)/computed tomography (CT) for cancer screening in Korean asymptomatic people.Between February 2004 and December 2006, 1,587 asymptomatic individuals underwent FDG PET/CT as part of a cancer screening program with some other diagnostic tests at the healthcare center of our hospital. After excluding patients with a history of malignant tumor, 1,336 subjects were enrolled. All PET/CT images were visually analyzed. In subjects showing positive findings for PET/CT or other screening tests, further diagnostic tests and pathological confirmation were performed.Of the 1,336 subjects, malignant tumors were found in 16 participants (1.2%, thyroid cancer: 9, lung cancer: 2, stomach cancer: 2, and others: 4). There were 47 cases (3.6%) of positive PET/CT findings—11 cases were true positive (thyroid cancer: 8, lung cancer: 1, renal cancer: 1, and invasive thymoma), and 36 false positive, and five cases were false negative. The overall detection rate of PET/CT was 0.8%, and the sensitivity, specificity, positive-predictive value, and negative-predictive value of PET/CT were 68.8, 97.2, 23.4, and 99.6%, respectively.Fluorodeoxyglucose positron-emission tomography has the potential to detect various kinds of malignant tumors in cancer screening test, and the overall detection rate of PET/CT was 0.8%. FDG PET/CT can be a useful cancer screening modality with the selection of high-risk group and appropriate combination with other screening modalities.

Keywords: ¹⁸F-fluorodeoxyglucose; Positron-emission tomography; Cancer screening

Direct radionuclide cystography imaging in colovesical fistula due to inguinal hernia operation complication by Muge Tamam; Hatice Sümeyye Yavuz; Şerafettin Hacımahmutoğlu; Mehmet Mülazımoğlu; Tulay Kacar; Tevfik Ozpacacı (pp. 693-696).

Colovesical fistula is an abnormal connection between the enteric and urinary systems, usually sigmoid colon, caused by various conditions. One cause of colovesical fistula is iatrogenic injury, such as induced by inguinal hernia surgery. We present a case of colovesical fistula. A 57-year-old male was admitted to a local hospital with complaints of dysuria and pneumaturia. He had a past history of total extraperitoneal laparoscopic inguinal hernia repair operation 7 years previously for bilateral inguinal hernia. The case was assessed with radiologic and scintigraphic techniques. Radiologic techniques (plain abdominal radiography, intravenous pyelogram, ultrasound examination, double-contrast barium enema, CT, MRI) were inadequate to determine the colovesical fistula. The colovesical fistula was visualized with direct radionuclide voiding cystography as an alternative scintigraphic method.

Keywords: Colovesical fistula; Direct radionuclide cystography; Inguinal hernia

Adverse allergic reaction to ¹³¹I MIBG by Naoya Ishibashi; Katsumi Abe; Satoru Furuhashi; Shoko Fukushima; Takashi Yoshinobu; Motoichiro Takahashi; Chiyuki Matsumoto; Kyoko Fukuda; Takayuki Kobayashi; Norisuke Mochizuki (pp. 697-699).

No adverse allergic reactions to iodine-131-metaiodobenzylguanidine (¹³¹I MIBG) at a diagnostic dose have been reported in the English literature. This report of a skin eruption in a 35-year-old man after an intravenous injection of ¹³¹I MIBG strongly suggests an adverse allergic reaction, and is the first to address such a side effect of ¹³¹I MIBG at a diagnostic dose. Erythematous maculopapular eruptions, some of which were contiguous, were seen in a symmetric disposition on the patient’s chest walls, elbows, neck and face 18 h after the ¹³¹I MIBG injection. Antiallergic treatment resolved the lesions completely. There were no possible causes of the exanthema other than the ¹³¹I MIBG injection. Urticaria related to the ¹³¹I MIBG injection and caused by type I allergic reaction was suspected, and these findings point to the possible risk of a hitherto unreported allergic skin reaction to ¹³¹I MIBG. We would like to draw the attention of nuclear physicians to this possible drawback of ¹³¹I MIBG.

Keywords: ¹³¹I MIBG; Adverse reactions; Skin eruption; Side effect; Radiopharmaceuticals

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Annals of Nuclear Medicine (v.23, #7)