Annals of Nuclear Medicine (v.22, #5)
Assessment of anatomic relation between pulmonary perfusion and morphology in pulmonary emphysema with breath-hold SPECT-CT fusion images by Kazuyoshi Suga; Yasuhiko Kawakami; Hideyuki Iwanaga; Noriko Hayashi; Akiko Seto; Naofumi Matsunaga (339-347).
Anatomic relation between pulmonary perfusion and morphology in pulmonary emphysema was assessed on deep-inspiratory breath-hold (DIBrH) perfusion single-photon emission computed tomography (SPECT)-CT fusion images.Subjects were 38 patients with pulmonary emphysema and 11 non-smoker controls, who successfully underwent DIBrH and non-BrH perfusion SPECT using a dual-headed SPECT system during the period between January 2004 and June 2006. DIBrH SPECT was three-dimensionally co-registered with DIBrH CT to comprehend the relationship between lung perfusion defects and CT low attenuation areas (LAA). By comparing the appearance of lung perfusion on DIBrH with non-BrH SPECT, the correlation with the rate constant for the alveolar-capillary transfer of carbon monoxide (DLCO/VA) was compared between perfusion abnormalities on these SPECTs and LAA on CT.DIBrH SPECT provided fairly uniform perfusion in controls, but significantly enhanced perfusion heterogeneity when compared with non-BrH SPECT in pulmonary emphysema patients (P < 0.001). The reliable DIBrH SPECT-CT fusion images confirmed more extended perfusion defects than LAA on CT in majority (73%) of patients. Perfusion abnormalities on DIBrH SPECT were more closely correlated with DLCO/VA than LAA on CT (P < 0.05).DIBrH SPECT identifies affected lungs with perfusion abnormality better than does non-BrH SPECT in pulmonary emphysema. DIBrH SPECT-CT fusion images are useful for more accurately localizing affected lungs than morphologic CT alone in this disease.
Keywords: Single-photon emission computed tomography (SPECT); Pulmonary perfusion; Pulmonary emphysema; Computed tomography (CT)
Assessment of alveolar epithelial permeability in Behçet’s disease with 99mTc-DTPA aerosol scintigraphy by Fikriye G. Gumuser; Timur Pirildar; Dilek Batok; Aysın Sakar; Ebru Ruksen; Elvan Sayit (349-355).
Behçet’s disease (BD) is a multisystem disorder characterized by vasculitis, and consists of a triad of recurrent ulcers of the oral and genital mucosa with relapsing uveitis. The prevalance of pulmonary involvement varies in the range of 1–10% in various studies and its complications are severe and life threatening. In this study, we investigated the changes of pulmonary epithelial permeability of patients with BD using technetium-99m diethylene triamine penta-acetic acid (99mTc-DTPA) aerosol scintigraphy, so as to begin the therapy regimen as soon as possible.Twenty-one nonsmoking patients with BD (8 women, 13 men; mean age 38.67 ± 8.86 years) and 15 healthy volunteer nonsmoking controls (8 women, 7 men; mean age 50.87 ± 12.45 years) underwent 99mTc-DTPA aerosol inhalation scintigraphy and pulmonary function tests (PFTs). Subjects inhaled 1480 MBq of 99mTc-DTPA for 4 min in the supine position. Scintigraphic data were recorded dynamically (1 frame/min) in the posterior projection on a 64 × 64 matrix for a 30-min period using a double-headed gamma camera (Infinia, GE, Tirat Hacarmel, Israel) equipped with a low-energy all-purpose parallel hole collimator. Half time of 99mTc-DTPA clearance (T 1/2) was calculated by placing a mono-exponential fit on the curves. Penetration index (PI) was also calculated by dividing the peripheral total counts by the sum of the peripheral and central total counts on the first minute image, in order to quantify the distribution of the inhaled aerosol.The clearance half time of 99mTc-DTPA radioaerosols in the BD patients (24.81 ± 6.22 min) was faster than in the normal control group (46.53 ± 22.41 min) (P = 0.004). There was also a significant difference between PI of the patients with BD (0.15 ± 0.03) and that of the controls (0.21 ± 0.06) (P = 0.002). No correlation was found between the mean T 1/2 values of 99mTc-DTPA clearance or the spirometric measurements in the BD patients. Penetration indices were not correlated with PFT in the BD patients.Lung epithelial permeability of the patients with BD was significantly higher than that of the normal subjects. The results of this study demonstrated that the assessment of lung epithelial permeability using 99mTc-DTPA aerosol scintigraphy could predict the presence of lung involvement in the early stages of BD.
Keywords: Behçet’s disease; Tc-99m DTPA aerosol scintigraphy; Pulmonary epithelial permeability; Pulmonary function test
Does cisplatin chemotherapy decrease the MDP uptake of normal bone? An experimental study by Ozhan Ozdogan; Turkan Ertay; Gulhan Arslan; Ali R. Sisman; Gamze Capa Kaya; Osman Yilmaz; Canan Çoker; Ataman Gure; Hatice Durak (357-362).
Bone scan is the accepted initial imaging modality for skeletal metastases. Cisplatin is a cell-cycle nonspecific antineoplastic agent used in some chemotherapy regimens. Knowing that platinum reacts with phosphate compounds such as methylenediphosphonic acid (MDP), decreases bone resorption and new bone formation, it can be proposed that cisplatin chemotherapy may decrease Tc-99m MDP bone uptake. We aimed to demonstrate, if present, the decrease in bone uptake and to determine the duration of this effect.Thirty male Wistar rats were randomized into five groups, namely, placebo group (G1) and cisplatin groups (G2, G3, G4, G5). Pre-therapy bone scintigraphies were obtained in all the groups. Cisplatin chemotherapy was given as infusion. Post-therapy bone scintigraphies were obtained 10 min, 1 h, 24 h, and 72 h after chemotherapy in groups G2–G5, respectively. A placebo bone scintigraphy was obtained 10 min after infusion of serum physiologic in G1. Plasma samples for cisplatin plasma values were obtained. The graphite furnace atomic absorption spectrophotometry technique was used for cisplatin analysis. Quantitative analysis (bone uptake ratios) was performed by drawing regions of interest on the right femur, vertebral column, and adjacent soft tissues. The injection/examination time delay and the net injected MDP doses were also noted.There was no statistically significant difference in bone uptake values, injected MDP doses or injection/examination time delay in any group. Cisplatin plasma values were significantly different in G2, G3, G4, and G5 (P < 0.05) but not in G1.Cisplatin chemotherapy seems to have no effect on the Tc-99m MDP uptake of normal bone.
Keywords: Cisplatin; Tc-99m MDP; Bone scintigraphy; Chemotherapy; Bone uptake
Usefulness of 201TlCl/123I-BMIPP dual-myocardial SPECT for patients with non-ST segment elevation myocardial infarction by Yoshimitsu Fukushima; Masahiro Toba; Keiichi Ishihara; Sunao Mizumura; Tomohiko Seino; Keiji Tanaka; Kyoichi Mizuno; Shin-ichiro Kumita (363-369).
Earlier 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.Consecutive 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.The 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).Of 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.
Keywords: Non-ST segment elevation myocardial infarction; Cardiac troponin T; 123I-BMIPP myocardial SPECT
Technetium-99m hexamethyl propylene amine oxime-labeled leukocyte scintigraphy at three different times in active ulcerative colitis: comparison with colonoscopy and clinico-biochemical parameters in the assessment of disease extension and severity by Funda Aydın; Dinç Dinçer; Fırat Güngör; Adil Boz; Serdar Akça; Akın Yıldız; Özgür Tosun; Binnur Karayalçın (371-377).
In this study, our objective was to define the usefulness of technetium-99m hexamethyl propylene amine oxime (Tc-99m HMPAO)-labeled leukocyte scintigraphy at three different time points in the assessment of disease extension and severity in patients with active ulcerative colitis (UC).Twenty-one consecutive patients (10 women, 11 men; mean age 42.4 ± 12 years) with active UC were prospectively studied. All patients were diagnosed by colonoscopy and histopathology prior to inclusion. Scintigraphy was performed at 1 h, 2 h, and 4 h after Tc-99m HMPAO-labeled leukocyte injection. Clinic-biochemical activity score, total colonoscopic activity score, and total scintigraphic activity score at 1 h, 2 h, and 4 h were calculated for each patient.Sensitivity, specificity, and accuracy values of Tc-99m HMPAO-labeled leukocyte scintigraphy were calculated as follows, respectively: 1 h imaging 86%, 73%, and 83%; 2 h imaging 89%, 74%, and 86%; 4 h imaging 90%, 58%, and 83% in the detection of active inflammatory segments. Even though no statistically significant difference was found between 1 h, 2 h, and 4 h imaging with respect to the sensitivity, specificity of labeled leukocyte scintigraphy, the largest area under the curve value was found for 2 h imaging.Tc-99m HMPAO-labeled leukocyte scintigraphy has been found to be correlated well with colonoscopy in the assessment of both the extension and severity of UC. We recommend 2 h scintigraphic imaging because it provides the largest area under the curve value and decreases the number of false-positive results.
Keywords: Colonoscopy; Imaging time; Tc-99m HMPAO; Ulcerative colitis
Evaluation of whole-body cancer screening using 18F-2-deoxy-2-fluoro-d-glucose positron emission tomography: a preliminary report by Takashi Terauchi; Takeshi Murano; Hiromitsu Daisaki; Daisuke Kanou; Hiroko Shoda; Ryutaro Kakinuma; Chisato Hamashima; Noriyuki Moriyama; Tadao Kakizoe (379-385).
18F-2-deoxy-2-fluoro-d-glucose positron emission tomography (FDG-PET) is a promising screening modality targeting whole body. However, the validity of PET cancer screening remains to be assessed. Even the screening accuracy for whole-body screening using FDG-PET has not been evaluated. In this study, we investigated the screening accuracy of PET cancer screening.A total of 2911 asymptomatic participants (1629 men and 1282 women, mean age 59.79 years) underwent both FDG-PET and other thorough examinations for multiple organs (gastrofiberscopy, total colonofiberscopy or barium enema, low-dose thin section computed tomography and sputum cytology, abdominal ultrasonography, an assay of prostate-specific antigen, mammography, mammary ultrasonography, Pap smear for the uterine cervix, and magnetic resonance imaging for the endometrium and ovaries) between February 2004 and January 2005, and followed sufficiently. The detection rate, sensitivity, specificity, and positive predictive value of FDG-PET were calculated using cancer data obtained from all examinations along with a 1 year follow-up.From among 2911 participants FDG-PET found 28 cancers, 129 cancers were PET negative. PET-positive cancers comprised seven colorectal cancers, four lung cancers, four thyroid cancers, three breast cancers, two gastric cancers, two prostate cancers, two small intestinal sarcomas (gastrointestinal stromal tumors), one malignant lymphoma, one head and neck malignancy (nasopharyngeal carcinoid tumor), one thymoma, and one hepatocellular carcinoma. PET-negative cancers included 22 gastric cancers and 20 prostate cancers that were essentially difficult to detect using FDG-PET. The overall detection rate, sensitivity, specificity, and positive predictive value were estimated to be 0.96%, 17.83%, 95.15%, and 11.20%, respectively.FDG-PET can detect a variety of cancers at an early stage as part of a whole-body screening modality. The detection rate of PET cancer screening was higher than that of other screening modalities, which had already shown evidence of efficacy. However, the sensitivity of PET cancer screening was lower than that of other thorough examinations performed at our institute. FDG-PET has some limitations, and cancer screening using only FDG-PET is likely to miss some cancers.
Keywords: FDG-PET; Cancer screening; Screening value; Sensitivity; Evidence
Development of a tweezers-type coincidence imaging detector by Seiichi Yamamoto; Yusuke Sakamoto; Keiichi Matsumoto; Michio Senda (387-393).
When employing F-18-fluorodeoxyglucose (FDG)-guided surgery to detect positron accumulation in isolated small organs, sampling these organs from opposite directions is a useful way of determining a tumor’s position, similar to sampling a small organ with tweezers. The coincidence method is suitable for this purpose because only the positrons between two detectors can be detected. For this purpose, we developed a tweezers-type coincidence imaging detector.The detector employs two depth-of-interaction (DOI) detectors positioned at the tip of the tweezers and images the positron distribution between them using the coincidence method. The DOI detector consists of a 4 × 3 Gd2SiO5:Ce (GSO) array optically coupled to a one-dimensionally arranged quad-photomultiplier tube. These GSOs were arranged to form a DOI detector using the Anger principle. The useful field of view is 20 mm × 15 mm. With these configurations, we could resolve 4 × 3 GSO arrays on a position histogram.Because the imaging detectors were positioned at the tip of the tweezers, one could easily sample the target part manually from opposed sides. A real-time image in coincidence between these two DOI detectors could be obtained. The point spread functions were approximately 3-mm full width at half-maximum (FWHM) parallel to the tweezers and 4-mm FWHM perpendicular to them. The sensitivity was ∼1% when the two imaging detectors were 10 mm apart.With these results, we conclude that the developed tweezers-type imaging detector has a potential to be a new instrument in nuclear medicine
Keywords: Positron; Tweezers; Coincidence; Imaging; Depth-of-interaction (DOI) detector
Detection of metastatic lesions from malignant pheochromocytoma and paraganglioma with diffusion-weighted magnetic resonance imaging: comparison with 18F-FDG positron emission tomography and 123I-MIBG scintigraphy by Akie Takano; Noboru Oriuchi; Yoshito Tsushima; Ayako Taketomi-Takahashi; Takahito Nakajima; Yukiko Arisaka; Tetsuya Higuchi; Makoto Amanuma; Keigo Endo (395-401).
To investigate the diagnostic features of whole-body diffusion-weighted magnetic resonance imaging (DWI) as compared with 2-[18F]-fluoro-2-deoxy-d-glucose positron emission tomography (FDG-PET) and 123I-meta-iodo-benzyl guanidine scintigraphy (MIBG) on metastatic lesions of patients with malignant pheochromocytoma or paraganglioma.We prospectively studied 11 patients with histologically confirmed pheochromocytoma/paraganglioma and possible metastatic lesions. FDG-PET, MIBG, and DWI examinations were performed within 1 week, and the images were visually interpreted. Abnormal positive uptake either on MIBG or on FDG-PET was considered as metastases. Abnormal high signal intensities on DWI were considered as metastases using conventional T1-and T2-weighted images as reference.FDG-PET and DWI demonstrated metastatic lesions in all 11 patients, but MIBG showed no metastatic lesions in two patients. The numbers of lymph node metastases depicted on FDG-PET, MIBG, and DWI were 19, 6, and 39; bone metastases were 50, 49, and 60; liver metastases were 9, 9, and 15; lung metastases were 5, 7, and 5, respectively. MIBG failed to demonstrate many metastatic lesions, which were demonstrated on FDG-PET or DWI, although two mediastinal lymph node metastases, three lung metastases, and six bone metastases, which were not seen on DWI, were clearly demonstrated on MIBG. DWI showed 15 liver metastases, but 6 of them were not seen on FDG-PET or MIBG.DWI may be particularly advantageous in depicting lymph node and liver metastases and may have a higher rate of detecting metastatic lesions when compared with MIBG or FDG-PET. The limitations of DWI were possible false-positive finding, and probable lower detectability of mediastinal lymph node and lung metastasis.
Keywords: Diffusion-weighted magnetic resonance imaging (DWI-MRI); 2-[18F]-fluoro-2-deoxy-D-glucose positron emission tomography (18F-FDG PET); 123I-meta-iodo-benzyl guanidine (123I-MIBG); Pheochromocytoma; Paraganglioma
Comparison of exercise and pharmacological stress gated SPECT in detecting transient left ventricular dysfunction by Hakan Demir; Yusuf Z. Tan; Serkan Isgoren; Gozde D. Gorur; Guliz Kozdag; Ertan Ural; Fatma Berk (403-409).
Transient left ventricular contractile dysfunction (TLVD) is observed owing to post-exercise stunning in patients with coronary artery disease (CAD). Pharmacological stimulation differs from exercise stress because it does not cause demand ischemia. The aim of this study was to determine whether TLVD could also be seen after pharmacological stress (dipyridamole).Of the patients in whom gated single-photon emission computed tomography (GSPECT) was performed in our institution from January 2004 to April 2007, 439 subjects with known or suspected CAD were included in the study. GSPECT was performed for all patients following exercise (group I, n = 220) or pharmacological stress (group II, n = 219) according to a 2-day (stress-rest) protocol after injection of Tc-99m methoxyisobutyl-isonitrile (MIBI). Stress, rest, and difference (stress-rest value) left ventricular ejection fractions (SLVEF, RLVEF, and DLVEF) and transient ischemic dilatation (TID) ratio were derived automatically. Summed stress score, summed rest score, and summed difference score (SDS) for myocardial perfusion were calculated using a 20-segment model and a five-point scoring system. An SDS > 3 was considered as ischemic. On the basis of the perfusion findings, patients were subdivided into a normal (group A, n = 216) and ischemia group (group B, n = 223). DLVEF and perfusion scores of all groups were compared. Relationships between DLVEF and perfusion, and between TID ratio and DLVEF were also evaluated.Stress-induced ischemia was observed in 223 of 439 patients (50.8%). In group A, the difference between stress and rest LVEF values was not significant (P = 0.670 and P = 0.200 for groups IA and IIA, respectively). However, LVEF was significantly decreased after stress compared with rest values for group B (P < 0.0001 for groups IB and IIB). TLVD (≤−5% for DLVEF) was observed in 20 of 216 (9%) and 81 of 223 subjects (36%) in patients in groups A and B, respectively (P < 0.0001). In group I, we found TLVD in 46 of 119 (39%) and 12 of 101 (12%) subjects, in patients with and without ischemia, respectively (P < 0.0001). On the other hand, in group II, TLVD was detected in 35 of 104 (34%) and 8 of 115 (7%) patients with and without ischemia, respectively (P < 0.0001). And also, we found significant good correlations between TID ratios and DLVEF values in four subgroups (r = −0.55, r = −0.62, r = −0.59, and r = −0.41; for groups IA, IB, IIA, and IIB, respectively, P < 0.0001 for all).Dipyridamole is believed to be less likely than exercise to induce ischemia. However, in this study, TLVD after stress was observed following not only exercise but also pharmacological stress, consistent with ischemia.
Keywords: Myocardial stunning; Gated SPECT; Transient left ventricular dysfunction; Tc-99m MIBI
Successive positron emission tomography measurement of cerebral blood flow and neuroreceptors in the human brain: an 11C-SA4503 study by Kiichi Ishiwata; Kenji Ishii; Yuichi Kimura; Kazunori Kawamura; Keiichi Oda; Toru Sasaki; Muneyuki Sakata; Michio Senda (411-416).
For evaluating a newly developed radioligand for positron emission tomography (PET), successive measurements of regional cerebral blood flow (rCBF) and the kinetics of the radioligand in the same subject are preferable in the first clinical trial. In this study, we demonstrate an example for the study of 11C-labeled 1-(3,4-dimethoxyphenethyl)-4-(3-phenylprophyl) piperazine (11C-SA4503) for mapping sigma1 receptors in the human brain. Five healthy male subjects underwent two successive PET scans with 15O-H2O to measure the rCBF and with 11C-SA4503 (dynamic 60-min scan). The brain kinetics of 11C-SA4503 was evaluated using the time-activity curve (TAC) of tissue in each of the 11 regions of the brain and the metabolite-corrected TAC of plasma on the basis of a two-tissue compartment fourparameter model. The estimated parameters were four rate constants: K 1, influx from plasma to brain tissue; k 2, efflux from tissue to plasma; k 3, association between tracer and receptors; and k 4, dissociation of tracer-receptor complex, and the binding potential (BP), k 3/k 4. 11CSA4503 was distributed all over the brain, and the TACs exhibited an accumulation pattern in all the 11 regions. K 1 of 11C-SA4503 correlated with rCBF, but the other three rate constant parameters and BP did not. The regional difference in the BP of 11C-SA4503 is compatible with those of sigma1 receptors. In conclusion, successive PET measurements of rCBF and the brain kinetics of radioligand-neuroreceptor binding are useful for the first clinical trial of a newly developed radioligand for mapping neuroreceptors, and the protocol is applicable to pathophysiological studies of brain disorders.
Keywords: 11C-SA4503; Sigma1 receptors; Cerebral blood flow; PET
In vivo imaging of microglial activation using a peripheral benzodiazepine receptor ligand: [11C]PK-11195 and animal PET following ethanol injury in rat striatum by Hiroshi Toyama; Kentaro Hatano; Hiromi Suzuki; Masanori Ichise; Sotaro Momosaki; Gen Kudo; Fumitaka Ito; Takashi Kato; Hiroshi Yamaguchi; Kazuhiro Katada; Makoto Sawada; Kengo Ito (417-424).
To investigate whether [11C]PK-11195, a specific peripheral benzodiazepine receptors (PBRs) ligand for positron emission tomography (PET), can show activated microglia in a rat brain injury model.On day 1, ethanol was injected into the rat’s right striatum (ST) using a stereotaxic operative procedure. On day 3, head magnetic resonance imaging (MRI) scans for surgically treated rats were performed to evaluate ethanol injury morphologically. On day 4, dynamic PET scans (17 injured rats and 7 non-injured controls) were performed for 60 min with an animal PET scanner under chloral hydrate anesthesia following a bolus injection of [11C]PK-11195 through tail vein. Because PBRs are present throughout the brain, there is no suitable receptor-free reference region. The reference tissue model may not be applicable because of low target to background ratio for low affinity of [11C]PK-11195 to PBRs. We evaluated the PBRs binding with regions of interest (ROIs)-based approach to estimate total distribution volume (V). We used an integral from 0 min to 60 min (V 60) as an estimate of V. On the coronal PET image, ROIs were placed on bilateral ST. Differences in right/left ST V 60 ratios between lesioned and unlesioned control rats were compared using unpaired t tests. Immunohistochemical staining was performed for confirming the presence of activated microglia following decapitation on the PET experiment day.The right/left ST V 60 ratios in lesioned rats (1.07 ± 0.08) were significantly higher than those in unlesioned control rats (1.00 ± 0.06, P < 0.05). On immunohistochemical staining, activated microglia were exclusively observed in the injured right ST but not in the noninjured left ST of the injury rats and the bilateral ST of the non-injured control rats.These results suggest that [11C]PK-11195 PET imaging would be a useful tool for evaluating microglial activation in a rat brain injury model.
Keywords: Animal PET; Microglia; [11C]PK-11195; Peripheral benzodiazepine receptors; Rat
The clinical utility of 99mTc-HMPAO SPECT in Fahr’s disease by Tunc Ones; Fuat Dede; Dilek Gunal; Gazanfer Ekinci; Hatice Memis; Tanju Y. Erdil; Sabahat Inanir; Halil T. Turoglu (425-428).
Fahr’s disease is a rare neurodegenerative syndrome, characterized by massive symmetrical intracerebral calcifications of the basal ganglia, dentate nuclei of the cerebellum, and the adjacent parenchyma. Computerized tomography (CT) is considerably more sensitive to detect these intracranial calcifications than other imaging modalities. The clinical, CT scan, and 99mTc-D,L-hexamethylpropylene amine oxime (99mTc-HMPAO) brain perfusion single-photon emission computerized tomography (SPECT) findings in a 42-year-old woman with Fahr’s disease are reported, and the clinical utility of 99mTc-HMPAO SPECT findings in Fahr’s disease is discussed in this article. In conclusion, 99mTc-HMPAO brain perfusion SPECT seems to be useful in the clinical approach to Fahr’s disease, and may provide more specific and clinically relevant information when compared with anatomical imaging.
Keywords: Basal ganglia calcification; Fahr’s disease; Idiopathic bilateral symmetrical striopallidodentate calcinosis; SPECT; 99mTc-HMPAO
Early relapse in a patient with Hodgkin’s disease and negative interim FDG-PET by Stefano Fanti; Paolo Castellucci; Vittorio Stefoni; Cristina Nanni; Monica Tani; Domenico Rubello; Valentina Ambrosini; Pier Luigi Zinzani; Roberto Franchi (429-432).
The role of F-18-fluorodeoxyglucose positron emission tomography (FDG-PET) in the assessment of lymphoma patients is well established, and PET is routinely used for initial staging, early evaluation of treatment response, and identification of disease relapse. The early evaluation of response to therapy (interim PET) has been reported to be an accurate predictor of progression-free survival, and end-treatment PET has been suggested to be unnecessary if interim PET results are negative. We report on a patient with Hodgkin’s disease with a positive PET scan at presentation and a negative interim PET (carried out after three cycles of adriamycin, bleomycin, vinblastine, and dacarbazine; ABVD). Despite uncomplicated clinical course, end-treatment PET (following six cycles) was positive, showing a very early relapse. For this reason, patient underwent further treatment; however, a complete remission was not obtained, and a poor prognosis is expected. This case testifies the possibility of early relapse of lymphoma even in the case of negative interim PET; it also supports the usefulness of end-treatment PET scan in lymphoma patients.
Keywords: Positron emission tomography; Hodgkin’s lymphoma; FDG diagnostic use
18F FDG-PET/CT findings in recurrent respiratory papillomatosis by Sudhakar N. J. Pipavath; Vivek Manchanda; David H. Lewis; Rodney A. Schmidt; Renato G. Martins; J. David Godwin (433-436).
Recurrent respiratory papillomatosis (RRP) is an indolent and primary disease of the larynx and the trachea and rarely extends to smaller airways. F-18 fluoro-2-deoxy-d-glucose positron emission tomography and computed tomography (FDG-PET/CT) evaluation in this condition has not been reported earlier. We report FDG-PET/CT findings in a case of RRP that included a large papillomatous lung mass resembling cancer.
Keywords: Recurrent respiratory papillomatosis; Positron emission tomography (PET); Computed tomography (CT)
Generation of planar images from lung ventilation/perfusion SPECT by Dale L. Bailey; Geoffrey P. Schembri; Benjamin E. Harris; Elizabeth A. Bailey; Robert A. Cooper; Paul J. Roach (437-445).
To develop a method of producing lung ventilation and perfusion (V/Q) planar images using forward projection of reconstructed single-photon emission computed tomography (SPECT) images through approximate attenuation (µ) maps generated from the lung emission scans alone, as transmission-based µ maps may not be routinely available.Synthetic µ maps are derived from 99mTc photopeak and “scatter” windows for the attenuation correction of the SPECT images. The attenuation-corrected SPECT images are forward projected at appropriate angles to give the equivalent of planar images. This method allows high-count planar images, as well as the SPECT images, to be produced from a single SPECT acquisition. In addition, isolated “single lung” views of lateral and medial projections without “shine-through” from the contra-lateral lung, which have not been available previously, can be formed.Comparison of reprojected images produced from CT-derived or synthetic µ maps displayed similar detail and radiopharmaceutical distribution. In a blinded comparison of “true” planar images with those from reprojecting the SPECT data using the synthetic µ maps, no difference in mismatched defect detection was found, and hence it was confirmed that the reprojected planar images could replace true planar images with no loss in planar diagnostic sensitivity.The reprojected planar images provide high-count, high-quality images, which are comparable with conventional 2D images.
Keywords: SPECT (single photon emission computed tomography); Lung; Pulmonary embolus; Gamma camera
Performance evaluation of a high-sensitivity large-aperture small-animal PET scanner: ClairvivoPET by Tetsuro Mizuta; Keishi Kitamura; Hiroshi Iwata; Yoshiyuki Yamagishi; Atsushi Ohtani; Kazumi Tanaka; Yoshihiro Inoue (447-455).
In this study, we evaluated the performance of a newly commercialized small-animal positron emission tomography (PET) scanner, ClairvivoPET, which provides significant advantages in spatial resolution, sensitivity, and quantitative accuracy.This scanner consists of depth of interaction detector modules with a large axial extent of 151 mm and an external 137Cs source for attenuation correction. Physical performances, resolution, sensitivity, scatter fraction (SF), counting rate including noise equivalent count (NEC) rate, quantitative accuracy versus activity strength, and transmission accuracy, were measured and evaluated. Animal studies were also performed.Transaxial spatial resolution, measured with a capillary tube, was 1.54 mm at the center and 2.93 mm at a radial offset of 40 mm. The absolute sensitivity was 8.2% at the center, and SFs for mouse-and rat-sized phantoms were 10.7% and 24.2%, respectively. Peak NEC rates for mouse-and rat-sized uniform cylindrical phantoms were 328 kcps at 173 kBq/ml and 119 kcps at 49 kBq/ml, respectively. The quantitative stability of emission counts against activity strength was within 2% over 5 half-lives, ranging from 0.6 MBq to 30 MBq. Transmission measurement based on segmented attenuation correction allowed 6-min and 10-min scans for mouse-and rat-sized cylindrical phantoms, respectively. Rat imaging injected with 18F-NaF resulted in visibility of fine bone structures, and mouse imaging injected with 18F-D-fluoromethyl tyrosine demonstrated the feasibility of using this system to obtain simultaneous time activity curves from separate regions, such as for the heart and tumors.ClairvivoPET is well suited to quantitative imaging even with short scan times, and will provide a number of advantages in new drug development and for kinetic measurement in molecular imaging.
Keywords: Small-animal PET; Performance evaluation; Time activity curves; Molecular imaging; Kinetic measurement
Usefulness of rate of increase in SPECT counts in one-day method of N-isopropyl-4-iodoamphetamine [123I] SPECT studies at rest and after acetazolamide challenge using a method for estimating time-dependent distribution at rest by Yoshifumi Kawamura; Michio Ashizaki; Shoko Saida; Hideharu Sugimoto (457-463).
When N-isopropyl-4-iodoamphetamine (123I-IMP) single-photon emission computed tomography (SPECT) studies at rest and after acetazolamide (ACZ) challenge are conducted in a day, the time-dependent change in IMP in the brain at rest should be estimated accurately. We devised the method and investigated whether our one-day method for measuring the rate of increase in SPECT counts allowed reduction in the acquisition time.Sequential, 5-min SPECT scans were performed. We estimated the time-dependent change in the brain using the change in slopes of two linear equations derived from the first three SPECT counts. For the oneday method, ACZ was administered 15 min or 20 min after IMP administration. The second IMP was administered 10 min after ACZ administration.Time-dependent changes in the brain were classified into 13 patterns when estimation was started at 5 min after IMP administration and 6 patterns when estimation was started at 10 min, and fitting coefficients were determined. The correlation between actual measurements at 37.5 min and estimates was high with a correlation coefficient of 0.99 or greater. Rates of increase obtained from 20-min data were highly correlated with those obtained from 15-min or 10-min data (r = 0.97 or greater). In patients with unilateral cerebrovascular disease, the rate of increase on the unaffected side was 44.4 ± 10.9% when ACZ was administered 15 min later and 48.0 ± 16.0% when ACZ was administered 20 min later, and the rates of increase with different timings of administration were not significantly different.The examination time may be reduced from 50 min to 45 min or 40 min as needed. The rate of increase was not influenced by the time frame for determination or the timing of ACZ administration. These findings suggest that our estimation method is accurate and versatile.
Keywords: 123I-IMP; SPECT counts; Vascular reserve; Acetazolamide; One-day method