Fatal consequences of decreased sensitivity to pain and temperature in a frontotemporal dementia patient.

Frontotemporal dementia (FTD) is a heterogeneous syndrome characterized by the progressive damage of frontal and temporal brain regions. These networks largely overlap with those involved in pain and temperature processing. Although the impaired perception of pain and temperature has been previously described to be relatively common in patients with FTD, these symptoms are often not consistently assessed by Neurologists. We present the case of a patient with a probable behavioral variant FTD who died due to scalding with hot water in the shower. Impairments in the perception of pain and temperature might have played a fundamental role in this accident.

Assessment of aortitis by semiquantitative analysis of 180-min 18F-FDG PET/CT acquisition images.

PURPOSE: The aim of this study was to evaluate the contribution of semiquantitative analysis of 180-min (18)F-fluorodeoxyglucose (FDG) positron emission tomography (PET)/CT images for the assessment of aortitis in cases of suspected large vessel vasculitis (LVV) and to establish a threshold index for application in the clinical setting. METHODS: This prospective study included 43 patients (mean age 67.5 ± 12.9 years) with suspicion of LVV (25 with a final diagnosis of aortitis). (18)F-FDG PET/CT scan was acquired 180 min after injection of 7 MBq/kg of (18)F-FDG. A semiquantitative analysis was performed calculating the aortic wall maximum standardized uptake value (SUVmax) (T), the lumen SUVmax (B) and the target to background ratio (TBR). These results were also compared with those obtained in a control population. RESULTS: The mean aortic wall SUVmax was 2.00 ± 0.62 for patients with aortitis and 1.45 ± 0.31 for patients without aortitis (p < 0.0001). The TBR was 1.66 ± 0.26 for patients with aortitis and 1.24 ± 0.08 for patients without aortitis (p < 0.0001). The differences were also statistically significant when the patients with aortitis and controls were compared. Receiver-operating characteristic (ROC) analysis revealed that the area under the curve was greater for the TBR than for the aortic wall SUVmax (0.997 vs 0.871). The highest sensitivity and specificity was obtained for a TBR of 1.34 (sensitivity 100%, specificity 94.4%). CONCLUSION: Semiquantitative analysis of PET/CT images acquired 180 min after (18)F-FDG injection and the TBR index of 1.34 show very high accuracy and, therefore, are strongly recommended for the diagnosis of aortitis in the clinical setting.

Evaluation of the contribution of the dynamic phase of lymphoscintigraphy to the detection of sentinel lymph node in breast cancer.

Aim: The aim of this study was to evaluate the contribution of an early dynamic phase (DP) of the lymphoscintigraphy (LS) to the detection of the sentinel lymph node (SLN) in breast cancer. Methods: This prospective study included 164 breast lesions in 161 consecutive patients (160 women, mean age 57.5 years). Patients with tumor >5 cm, multicentric, palpable nodes, axillary involvement, previous surgery, lymphadenectomy, radio or chemotherapy were not included. All patients underwent preoperative LS before surgery. DP immediately after injection of [99mTc]Nanocolloid followed by early and delayed planar images (EPI and DPI) were acquired. Results: SLN was detected in 162/164 lesions (98.8%). In 115 (71%) DP showed no lymph node uptake and the SLN was identified only by EPI and DPI. A focal uptake by at least one lymph node was observed in DP in the remaining 47 lesions (29%). Although in 30/74 lesions DP did not provide additional information to EPI and DPI, nevertheless in 17 cases (10.5%) DP was essential to identify correctly the SLN. Conclusion: We concluded that DP, by allowing a better interpretation of the lymphatic drainage pattern, provides unique information to distinguish the correct SLN from other lymph nodes and is recommended as the first part of LS.

Preparation, radiolabeling with 99mTc and 67Ga and biodistribution studies of albumin nanoparticles covered with polymers. / Preparación, radiomarcaje con 99mTc y 67Ga y estudios de biodistribución de nanopartículas de albúmina con recubrimientos poliméricos.

OBJECTIVE: To optimize radiolabeling with 99mTc and 67Ga of albumin nanoparticles coated with 4 differents synthetic polymers and to evaluate their stability in vivo and in vitro, as well as their biodistribution in vivo after intravenous administration. MATERIAL AND METHODS: The nanoparticles were prepared using albumin and NOTA-modified albumin by the desolvation method and coated with 4 different polymers; HPMC, GMN2, GPM2 and GTM2. They were purified, lyophilized and characterized. Radiolabelling with 99mTc was perfomed with 74 MBq of 99mTc sodium pertechnetate, previously reduced with and acid solution of tin chloride at different concentrations (0.003, 0.005, 0.007, 0.01, 0.05 and 0.1mg/ml) and at different times (5, 10, 15, 30 and 60minutes) and temperatures (room temperature, 40°C and 60°C). Radiolabelling with 67Ga was perfomed by incubation of the nanoparticles with 37 MBq of 67Gallium chloride (obtained from commercial gallium-67 citrate) at different times (10 and 30minutes) and temperatures (room temperature, 30°C and 60°C), and posterior purification with microconcentrators. The radiochemical purity was evaluated by TLC. Stability studies of radiolabeled nanoparticles in physiological serum and blood plasma were perfomed. Biodistribution studies of nanoparticles coated with GPM2 polymer were carried out in Wistar rats after intravenous administration of the nanoparticles. Control animals were carried out with 99mTc sodium pertechnetate and 67Ga chloride. To do so, the animals were killed and activity in organs was measured in a gamma counter. RESULTS: 99mTc labeling was carried out optimally with a tin concentration of 0.007mg/ ml for the GPM2 nanoparticles and 0.005mg / ml for the rest of the formulations, with a radiolabelling time of 10minutes at room temperature. In the case of 67Ga the label was optimized at 30° C temperature and 30minutes of incubation. In both cases the radiochemical purity obtained was greater than 97%. The nanoparticles showed high stability in vitro after 48hours of labeling (70% nanoparticles labeled with 99mTc and 90% those labeled with 67Ga). Biodistribution studies of nanoparticles 99mTc -GPM2 and 67Ga -NOTA-GPM2 showed a high accumulation of activity in the liver at 2 and 24hours after intravenous administration. CONCLUSION: The labeling procedure with 99mTc and 67Ga of albumin and albumin modified with NOTA nanoparticles allows obtaining nanoparticles with high labeling yields and adequate in vitro stability, allowing their use for in vivo studies.

[18F-FDG PET/CT in response evaluation of gastrointestinal stromal tumours treated with imatinib]. / La PET/TAC con 18F-FDG en la evaluación de la respuesta de los tumores del estroma gastrointestinal al tratamiento con imatinib.

OBJECTIVE: Several studies have demonstrated the effective use of adjuvant treatment with Imatinib mesylate for unresectable, metastatic or recurrent gastrointestinal stromal tumours (GIST). We retrospectively evaluated the role of 18F-FDG PET/CT scanning in assessing the response of GIST patients to imatinib mesylate therapy. MATERIALS AND METHODS: Eight consecutive patients with GIST confirmed by surgery (4 stomach, 2 small bowel, 1 small bowel and peritoneum, and 1 rectum) underwent eighteen 18F-FDG PET/CT imaging after beginning imatinib mesylate therapy (400 mg/day or greater if disease progression). PET/CT scan was acquired 60-90 minutes after the intravenous injection of 333-707 MBq of 18F-FDG. Visual and semiquantitative (standardized uptake value [SUV]) analysis of images was performed. Response to therapy was assessed according to EORTC recommendations for PET. Results were confirmed by clinical follow-up, radiographic findings or histological analysis. RESULTS: Complete response to imatinib mesylate was observed in 5 patients. Four had abdominal lymph nodes, associated with liver metastases in 2, and the other had a residual tumour mass. Partial response (reduction in SUV and in the extent of FDG uptake) was demonstrated in a patient with lung nodules. Disease progression was observed in one patient who had developed new liver metastases on the PET/CT scan. One patient with multiple peritoneal implants and abdominal mass was a non-responder and died 2 months after the 18F-FDG PET/CT. CONCLUSION: 18F-FDG PET/CT scan identified the degree of GIST response to imatinib therapy. Patients who responded to therapy showed normalisation of FDG uptake or a decrease in the SUV of lesions.

11C-PIB retention patterns in white and grey cerebral matter in idiopathic normal pressure hydrocephalus patients. A visual analysis. / Patrones de retención de 11C-PIB en la sustancia blanca y en la sustancia gris cerebral de pacientes con hidrocefalia a presión normal idiopática. Un análisis visual.

OBJECTIVE: Cortical cerebral amyloid disease, a hallmark of Alzheimer's disease, has also been observed in idiopathic normal pressure hydrocephalus (iNPH). The aim of this study was to compare the 11C-PIB PET/CT retention pattern in iNPH patients and healthy subjects. MATERIAL AND METHODS: A comparison was made of the 11C-PIB PET/CT retention pattern in 13 iNPH patients selected for surgical deviation, compared to a normal control population. Images were visually analyzed and scored for gray matter and white matter (WM) from 1 to 4 (slight to very high PIB retention). The scoring was analyzed in both groups separately for infra- and supra-tentorial regions. A comprehensive clinical report was presented in terms of positive, negative, or equivocal. RESULTS: 11C-PIB PET/CT scan were reported as negative in 8, positive in 3, and equivocal in 2. Five of 13 patients showed at least one cortical area with PIB retention with an intensity higher than that observed in the control group. Overall, white matter (WM) PIB retention of iNPH scored lower than in the control group, showing a statistically significant difference in the infratentorial WM (92/104 vs 54/56; p<.05) and a tendency to be lower in the supratentorial regions (70/84 vs 122/156, p=.327), in particular in the upper periventricular region (25/28 vs 40/52; p=.134). CONCLUSIONS: The PIB retention pattern seems to be different in NPH, compared to normal subjects. PIB retention in WM of NPH appears less intense than in healthy subjects, and they show a higher degree of PIB retention in cortical regions. This deserves to be taken it into account.

Contribution of 11C-Choline PET/CT in prostate carcinoma biochemical relapse with serum PSA level below 1 ng/ml. / Aportación de la PET/TC con 11C-colina en la recidiva bioquímica del cáncer de próstata con antígeno específico prostático sérico inferior a 1 ng/ml.

OBJECTIVE: 11C-choline PET/CT has demonstrated good results in the restaging of prostate cancer (PCa) with high serum prostate specific antigen (PSA), but its use in patients with low serum PSA is controversial. Our aim was to evaluate the contribution of 11C-choline PET/CT in patients with PCa, biochemical relapse and PSA <1 ng/ml. MATERIAL AND METHOD: Fifty consecutive patients (mean age: 65.9±5.6 years) with biochemical relapse of PCa and serum PSA <1ng/ml were evaluated retrospectively. PET/CT was performed 20min after intravenous administration of 555-740 MBq of 11C-choline. Minimum follow up time was 30 months. RESULTS: Twenty-one out of 50 patients (42%) had an abnormal 11C-choline PET/CT. In 7 out of 21 patients (14%) tumor was confirmed (4 in prostatic bed, 4 in pelvic lymph nodes, 2 in mediastinal lymph nodes and one synchronous sigmoid carcinoma), and in all cases the initial therapeutic planning was modified. In 2 patients (4%) subsequent tests diagnosed a benign disease (one sarcoidosis, one tuberculosis sequelae) and in 3 patients (6%) they ruled out pathology. The other 9 patients (18%) had no further assessment (7 mediastinal and 4 pelvic lymph nodes). Twenty-nine out of 50 patients (58%) had a normal PET/CT. At 30 months, follow up recurrence was confirmed only in 2 of these patients. CONCLUSIONS: 11C-choline PET/CT proved its usefulness in demonstrating tumor in 14% of patients with BR of PCa and serum PSA <1ng/ml, with therapeutic implications. In 4% of patients a benign condition was detected. A normal 11C-choline PET/CT was associated with a very low rate of recurrence at 30 months.

Candida Esophagitis Incidentally Detected by 18F-FDG PET/CT in Metastatic Lung Adenocarcinoma.

The diagnostic significance of esophageal 18F-FDG uptake in oncologic patient is challenging. It may represent normal physiological uptake, inflammation, infection, or neoplasia. We present a patient with a recent diagnosis of non-small cell lung cancer stage IV and esophageal mild uptake on 18F-FDG PET/CT scan. Biopsy of esophageal mucosa demonstrated Candida esophagitis.

Ventilation/Perfusion SPECT lung scintigraphy and computed tomography pulmonary angiography in patients with clinical suspicion of pulmonary embolism.

UNLABELLED: The aim was to compare ventilation/perfusion SPECT lung scintigraphy (V/Q-SPECT) and computed tomography pulmonary angiography (CTPA) in patients with suspicion of pulmonary embolism (PE). MATERIAL AND METHODS: This prospectively designed study included 53 patients with intermediate or high clinical probability of PE. A V/Q-SPECT and CTPA was performed on all patients. The V/Q-SPECT was interpreted according to the European Association of Nuclear Medicine and Molecular Imaging (EANMMI) guidelines. CTPA was reported as positive, negative, or indeterminate. RESULTS: CTPA was positive in 22 cases, negative in 28, and indeterminate in 3. V/Q-SPECT was positive in 27 cases, negative in 24, and non-diagnostic in 2. In the 22 with positive CTPA, V/Q-SPECT was positive in 18, negative in 3, and non-diagnostic in 1. In the 28 with negative CTPA, V/Q-SPECT was positive in 8, negative in 19, and non-diagnostic in 1. In the 3 with indeterminate CTPA, V/Q-SPECT was positive in 1 and negative in 2. In the 2 non-diagnostic cases V/Q-SPECT, CTPA was positive in 1 and negative in one. In the 10 high clinical probabilities, CTPA and V/Q-SPECT were positive in 7, negative in 2, and in 1, CTPA was positive and V/Q-SPECT negative. In the 38 intermediate probability group, CTPA and V/Q-SPECT were positive in 11, negative in 17, with CTPA negative and V/Q-SPECT positive in 8, and in 2 CTPA was positive and V/Q-SPECT negative. The results show that V/Q-SPECT detected PE in 5 patients more than CTPA. CONCLUSION: Our results show a 77% concordance of both techniques. Overall V/Q-SPECT detected PE in 18% more patients than CTPA in the intermediate group. Both techniques have a complementary role when a diagnosis cannot be made with one of them.

New insight of functional molecular imaging into the atheroma biology: 18F-NaF and 18F-FDG in symptomatic and asymptomatic carotid plaques after recent CVA. Preliminary results.

AIM: The identification of the vulnerable atheroma plaque could allow a more effective treatment of cerebrovascular accident (CVA). Active calcification and inflammation of the carotid atheroma were assessed and compared in symptomatic and asymptomatic plaques by 18F-NaF and 18F-FDG PET/CT. METHODS: Nine patients investigated for recent CVA and no preventive treatment with statins were enrolled. In each patient, at least one atheroma plaque was detected by CT angiogram. In total, 18 plaques were available: 9 symptomatic and 9 asymptomatic. 18F-NaF uptake and 18F-FDG uptake by each plaque were assessed visually and semiquantitatively by calculating target/background ratios (TBRs) and TBR indexes (TBR symptomatic/TBR asymptomatic and 18F-NaF TBR/18F-FDG TBR within each of the 2 clinical groups of plaques). RESULTS: All plaques showed 18F-NaF and 18F-FDG uptake, and semiquantitation showed higher 18F-NaF uptake by 11 of the 18 plaques, 6 symptomatic and 5 asymptomatic. In the symptomatic group, the mean 18F-NaF TBR was 2·12 ± 0·44, and in the asymptomatic group, it was 1·85 ± 0·46. The 18F-NaF/18F-FDG showed that, overall, 18F-NaF uptake is higher than 18F-FDG. In the symptomatic plaques, the 18F-NaF was higher for the low calcium content and the lowest for the high. CONCLUSION: Active calcification and inflammation are simultaneous processes in the symptomatic and asymptomatic carotid atheroma. However, active calcification seems predominant over inflammation in both groups. In the symptomatic plaques, the highest 18F-NaF uptake does not correspond with the largest calcium content. These patterns open new insights on the role of 18F-NaF in the study of calcification and in the identification of the vulnerable carotid atheroma.

Patterns of 11C-PIB cerebral retention in mild cognitive impairment patients.

OBJECTIVE: To evaluate the patterns of cerebral cortical distribution of (11)C-PIB in patients with mild cognitive impairment (MCI). MATERIAL AND METHODS: The study included 69 patients (37 male, age range 42-79 years) with MCI, sub-classified as 53 with amnestic-MCI (A-MCI), and 16 with non-amnestic-MCI (NA-MCI). Patients underwent (11)C-PIB PET/CT scan 60min after intravenous injection of the radiotracer. A visual analysis of the images was performed by 2 experienced physicians. (11)C-PIB-positive studies were considered when gray matter uptake was equal to or greater than white matter. According to the regions involved, (11)C-PIB-positive studies were classified into A-pattern (predominant retention in frontal, anterior cingulate, lateral temporal, and basal ganglia) and B-pattern (generalized retention). RESULTS: Thirty-nine of the 69 (56%) patients with MCI showed (11)C-PIB retention. Of the 53 A-MCI patients, 36 (68%) showed (11)C-PIB retention. Eleven out of 36 (30%) positive scans in A-MCI patients showed A-pattern, and 25 out of 36 (70%) patients had a B-pattern. Positive (11)C-PIB was observed in 3 out of 16 (19%) patients with NA-MCI. Regional distribution in these 3 patients showed A-pattern in 1, and B-pattern in 2 patients. CONCLUSION: Cortical retention of (11)C-PIB was more frequent in A-MCI than in NA-MCI patients, and also B-pattern than A-pattern in the (11)C-PIB positive group. The recognition of (11)C-PIB distribution patterns allows MCI patients to be classified, and the A-pattern may offer a therapeutic window for potential future treatments.

(18)F-sodium fluoride PET/CT for the in vivo visualization of Mönckeberg's sclerosis in a diabetic patient.

Diabetes is a major frequent cause of atherosclerosis vascular disease. Arterial calcification in diabetic patients is responsible for peripheral vascular involvement. Molecular imaging using (18)F-sodium fluoride ((18)F-NaF) positron emission tomography (PET)/computed tomography (CT) has been recently proposed as a marker to study the in vivo mineralization process in the atheroma plaque. A 69-year-old man with a history of type 2 diabetes and no clinical evidence of peripheral arterial disease underwent an (18)F-NaF PET/CT scan. A linear, well-defined (18)F-NaF uptake was detected along the femoral arteries. In addition, the CT component of the PET/CT identified an unsuspected "tram-track" calcification in his femoral arteries, suggestive of medial calcification (Mönckeberg's sclerosis). In other vascular territories, focal (18)F-NaF uptake was also detected in carotid and aorta atheroma plaques. Molecular imaging with (18)F-NaF PET/CT might provide new functional information about the in vivo vascular calcification process in diabetic patients.

(18)F-FDG PET/CT for the detection of large vessel vasculitis in patients with polymyalgia rheumatica.

PURPOSE: Polymyalgia rheumatica (PMR) may present together with large vessel vasculitis (LVV), and frequently requires a more intensive therapy. The aim of the study was to evaluate the impact of (18)F-FDG PET/CT in the diagnosis and management of LVV associated to PMR. MATERIAL AND METHODS: This prospective study included 40 consecutive patients (27 women/13 men, 68.10±10.27 years) with PMR and suspicion of associated LVV submitted for (18)F-FDG PET/CT. A PET/CT scan was obtained 180 min after (18)F-FDG intravenous injection. A visual analysis was performed on the images. Five vascular regions were evaluated: supra-aortic trunks (SAT), thoracic aorta (TA), abdominal aorta (AA), iliac arteries (IA), and femoral/tibioperoneal arteries (FTA). The intensity of uptake was graded from 0 to 3. A final diagnosis of LVV was established in 26/40 patients (65%). RESULTS: In the 26 patients with a diagnosis of LVV, the highest intensity of (18)F-FDG uptake was observed in the TA, SAT, and FTA. All of these patients showed uptake at the TA, with grade 2 and 3 in most cases. In 4 of the 14 patients without LVV, no uptake was observed in any vascular region, and in the other 10 patients only a grade 1 uptake was observed in 1 or to 2 territories. Out of the 20 treated LVV patients, (18)F-FDG PET/CT led to a therapeutic change in 17 (85%). CONCLUSION: (18)F-FDG PET/CT was useful in identifying patients with LVV associated to PMR. The detection of vascular inflammation had an important impact, and led to a change of treatment in a high percentage of patients with LVV.

Detection of mediastinitis after heart transplantation by gallium-67 scintigraphy.

We report the findings of a patient with post-cardiac transplant mediastinitis detected by 67Ga-citrate imaging. Fever and leukocytosis were the first clinical signs suggesting infection. The usual diagnostic modalities, including CT and ultrasound, failed to identify the site of infection. A 67Ga scan showed intense abnormal uptake behind the sternum. The site of uptake was shown by necropsy to be necrotic tissue involving cardiac sutures, pulmonary arteries, and the aorta due to infection with Haemophilus aphrophilus.

Total-body scintigraphy with thallium-201 and iodine-131 in the follow-up of differentiated thyroid cancer.

UNLABELLED: We analyzed the significance of total body scintigraphy with 201Tl in the follow-up of patients with differentiated thyroid cancer, both in the preablation and ablated stages. METHODS: Prospective assessment was performed in 116 patients who were involved in 178 studies (115 in preablation and 63 after ablation). For ablation, an absence of uptake in the thyroid bed was required in the total 131I follow-up scan after 131I ablation therapy. Each study consisted of a 201Tl scan performed while the patient was receiving thyroid hormone therapy, an 131I scan performed when endogenous thyroid-stimulating hormone levels were higher than 50 mlU/ml and determination of thyroglobulin (Tg) concentration using the same sample. RESULTS: In the 115 scans in the preablation group, the findings for 201Tl and 131I agreed in 26 scans and disagreed in 89 scans. In 59 discordant studies, only 131I detected focal accumulation, and, in 54 of these, Tg levels were undetectable. Of the other 30 discordant studies, 201Tl and 131I detected focal uptake in 27 studies, although they did not reveal the same lesions, and in 3 studies, only 201Tl detected focal accumulation; in these 30 studies, the association of detectable Tg predominated. Of the 63 studies in the ablated group, the results agreed for the two tracers in 49 and disagreed in 14 studies. In 13 of the 14 discordant studies, 201Tl detected focal uptake, and, in 10 of these, Tg was detectable. Thus, 31 of the 116 patients assessed (15 preablation and 16 ablated) had at least one lesion that was detected by 201Tl but not detected by 131I. A definitive diagnosis could be established in 26 patients, and the presence of thyroid cancer was confirmed in 23. The sensitivity and specificity in the ablated group were 94% and 96%, respectively, for 201Tl and 29% and 100%, respectively, for 131I. CONCLUSION: The high sensitivity of 201Tl scintigraphy in detecting tumor tissue indicates that the inclusion of this technique in the follow-up of patients with differentiated thyroid carcinoma should be considered in both the preablation and the ablated stages.

Prospective clinical comparison of non-corrected and attenuation- and scatter-corrected myocardial perfusion SPECT in patients with suspicion of coronary artery disease.

Attenuation artefacts decrease the specificity of myocardial perfusion single-photon emission computed tomography (SPECT). In this paper, the results of a prospective study evaluating the clinical applicability of attenuation and scatter correction in myocardial perfusion SPECT are presented. Of 607 patients in whom post-stress 99mTc-tetrofosmin myocardial perfusion SPECT was performed due to suspicion of coronary artery disease, 99 also underwent coronary angiography (CAG). A simultaneous emission/transmission acquisition was performed. A multiple linear array of 153Gd sources and four independent energy windows were used for attenuation and scatter correction. A blind separate analysis of non-corrected (NC) and attenuation- and scatter-corrected (AC-SC) images was performed with scores of zero (no uptake) to three (normal uptake). The final diagnosis was based on CAG findings, and stenoses of > or =70% were considered to be significant. NC images had a sensitivity of 92% and a specificity of 46%. In AC-SC images, the sensitivity decreased to 76%, but the specificity increased to 71%. The decrease in the sensitivity of AC-SC images was observed in all three coronary regions. Attenuation and scatter correction increased the specificity in the right coronary region, but decreased the specificity in the left anterior descending coronary region. In 13 of the 99 patients, AC-SC images showed false positive findings due to count deficiency in the anterior wall with normal CAG. The size of perfusion defects was decreased in AC-SC images (from 5.01 +/- 2.74 to 3.15 +/- 2.50 segments). The severity of perfusion defects was higher in NC (1.10 +/- 0.60) than in AC-SC (1.28 +/- 0.56) images. The combined evaluation of NC and AC-SC images was in agreement with the CAG findings in 79% of patients. It can be concluded that, when compared with NC images, AC-SC images improved the specificity in the right coronary region and decreased the sensitivity in all three coronary regions. Attenuation and scatter correction may generate anterior wall defects with normal CAG. The analysis of AC-SC images cannot be used alone for the diagnosis of coronary artery disease. In the clinical setting, combined NC and AC-SC images are recommended for the evaluation of post-stress myocardial perfusion SPECT.