Investigation of tumor assessment between two PET systems using various indices: comparison between PET/CT and PET/MRI systems.

This study aimed to determine the comparability of tumor-uptake indices of 18F-FDG in positron emission tomography/computed tomography (PET/CT) and positron emission tomography/magnetic resonance imaging (PET/MRI). 2-[fluorine-18]-fluoro-2-deoxy-D-glucose (FDG) PET/CT and PET/MRI were performed on 55 patients with confirmed primary malignancies. PET/CT preceded PET/MRI in all examinations. Accumulation of 18F-FDG in lesions and normal organs (brain, liver) was measured. Maximum and peak standardized uptake values (SUVs; SUVmax and SUVpeak, respectively), metabolic tumor volume (MTV), and total lesion glycolysis (TLG) with margin thresholds of SUV of 50% (MTV50%; TLG50%, respectively) were measured as indices for comparison of measurements in tumors. Comparative indices with tumor SUVmax and liver ratio (TLRmax), brain ratio (TBRmax) were calculated. These indices were compared between PET/CT and PET/MRI examinations. The data measured using PET/CT and PET/MRI showed significant correlations for all tumor indices. The correlation was strongest for SUVpeak (r = 0.933), followed by TBRmax (r = 0.929); and the index ratio of (PET/CT)/(PET/MRI) data was close to 1.0 for TLRmax (1.00 ± 0.22) and TBRmax (1.01 ± 0.21), followed by MTV50% (0.82 ± 0.33) and TLG50% (1.18 ± 0.45). The values of all indices showed strong correlations between PET/CT and PET/MRI examinations. Among them, TLRmax, TBRmax, MTV50%, and TLG50% showed a close value and may be useful for comparison of tumor evaluation between two PET systems.

Optimized workflow and imaging protocols for whole-body oncologic PET/MRI.

Although PET/MRI has the advantages of a simultaneous acquisition of PET and MRI, high soft-tissue contrast of the MRI images, and reduction of radiation exposure, its low profitability and long acquisition time are significant problems in clinical settings. Thus, MRI protocols that meet oncological purposes need to be used in order to reduce examination time while securing detectability. Currently, half-Fourier acquisition single-shot turbo spin echo and 3D-T1 volumetric interpolated breath-hold examination may be the most commonly used sequences for whole-body imaging due to their shorter acquisition time and higher diagnostic accuracy. Although there have been several reports that adding diffusion weighted image (DWI) to PET/MRI protocol has had no effect on tumor detection to date, in cases of liver, kidney, bladder, and prostate cancer, the use of DWI may be beneficial in detecting lesions. Another possible option is to scan each region with different MRI sequences instead of scanning the whole body using one sequence continuously. We herein report a workflow and imaging protocols for whole-body oncologic PET/MRI using an integrated system in the clinical routine, designed for the detection, for example by cancer screening, of metastatic lesions, in order to help future users optimize their workflow and imaging protocols.

Comparison of integrated whole-body PET/MR and PET/CT: Is PET/MR alternative to PET/CT in routine clinical oncology?

PURPOSE: To compare the diagnostic accuracy of whole-body PET/CT and integrated PET/MR in relation to the total scan time durations. METHODS: One hundred and twenty-three (123) patients (40 males and 83 females; mean age 59.6 years; range 20-83 years) with confirmed primary cancer and clinical suspicion of metastatic disease underwent whole-body 18F-FDG-PET/CT and 18F-FDG-PET/MR. Data acquisition was done after intravenous administration of 110-301 MBq radioactivity of 18F-FDG, and PET/MR data were acquired after the PET/CT data acquisition. The mean uptake times for PET/CT and PET/MR acquisition were 68.0 ± 8.0 and 98.0 ± 14 min, respectively. Total scan time was 20.0 and 25.0 min for whole-body PET/CT and PET/MR imaging. RESULTS: The reconstructed PET/CT and PET/MR data detected 333/355 (93.8 %) common lesions in 111/123 (90.2 %) patients. PET/CT and PET/MR alone detected 348/355 and 340/355 lesions, respectively. No significant (p = 0.08) difference was observed for the overall detection efficiency between the two techniques. On the other hand, a significant difference was observed between the two techniques for the detection of lung (p = 0.003) and cerebrospinal (p = 0.007) lesions. The 15 lesions identified by PET/CT only included 8 lung, 3 lymph nodes, 2 bone, and 1 each of peritoneal and adrenal gland lesions. On the other hand, 7 (6 brain metastatic lesions and 1 bone lesion) were identified by PET/MR only. CONCLUSION: Integrated PET/MR is a feasible whole-body imaging modality and may score better than PET/CT for the detection of brain metastases. To further prove diagnostic utility, this technique requires further clinical validation.

VALIDATION OF THERAPEUTIC RESPONSE ASSESSMENT BY BONE SCINTIGRAPHY IN PATIENTS WITH BONE-ONLY METASTATIC BREAST CANCERS DURING ZOLEDRONIC ACID TREATMENT: COMPARISON WITH COMPUTED TOMOGRAPHY ASSESSMENT.

PURPOSE: To validate the use of bone scintigraphy (BS) versus computed tomography (CT) for therapeutic monitoring in patients during treatment with zoledronic acid. MATERIALS AND METHODS: Eleven patients with bone-only metastatic disease and being treated with zoledronic acid were included. The effects of therapies including chemotherapy and hormone therapy were evaluated in 25 separate examinations in total as follows: complete response (CR), when no bone metastasis was visible; partial response (PR), when a decrease in the lesion area was detected; stable disease (SD), when no or slight change was observed; and progressive disease (PD), when new or enlarged lesion areas were observed. RESULTS: The accuracies of examination by Readers 1, 2, and 3 respectively were 76%, 80% and 76% for BS, 52%, 48%, and 40% for CT, and 64%, 52% and 60% for BS and CT combined with Readers 2 and 3 observing significant differences between CT and BS results. The rates of interobserver agreement between Readers 1 and 2, between Readers 1 and 3, and between Reader 2 and 3 respectively, were 84%, 80% and 88% (κ = 0.648, 0.561 and 0.766) for BS, 52%, 56%, and 60% (κ = 0.180, 0.278 and 0.282) for CT, and 52%, 60%, and 56% (κ = 0.215, 0.282 and 0.232) for CT and BS combined. CONCLUSION: BS is effective for assessing the response of bone metastasis to therapy in patients during zoledronic acid treatment.

[Abnormal lung uptake of 123I-BMIPP].

An eighty-one-year-old male patient with a feeling of chest pressure was admitted to our hospital for investigation of the heart. 201T1/123I-BMIPP dual scintigraphy was performed and multiple uptakes of 123I-BMIPP were detected in the lung, but not of 201T1. His chest X-ray and chest CT showed no abnormal lesions in the corresponding regions. There have been no reports that 123I-BMIPP accumulate in the lung. The possible cause of the lung uptake was embolism from aggregated 123I-BMIPP due to cold tempetatures.

Comparison between sarcoidosis and IgG4-related disease by whole-body 67Ga scintigraphy.

PURPOSE: The aim of this study was to compare uptake lesions in sarcoidosis and IgG4-related disease through gallium-67 ((67)Ga) scintigraphy to differentiate between the two diseases. MATERIALS AND METHODS: Whole-body (67)Ga scintigraphy findings of 27 patients with sarcoidosis and 16 with IgG4-related disease were reviewed between 2005 and 2011 at our hospital. RESULTS: In the case of patients with sarcoidosis, significant accumulation of (67)Ga was observed in the lacrimal gland in the case of 26 patients (96%), in mediastinal lymph nodes (LNs) in 23 (85%), in pulmonary hilar LNs in 21 (78%), in the parotid gland in 10 (38%), in supraclavicular LNs in eight (30%), in muscles in seven (26%), in the lung in five (18%), in inguinal LNs in four (15%), in submandibular LNs in two (7%), and in the heart, spleen, kidney and para-aorta in one patient (4%). In patients with IgG4-related disease, abnormal uptake was detected in the pulmonary hilar LNs in 12 patients (75%), in the lacrimal gland in 10 (62%), in the pancreas in 10 (62%), in the parotid gland in six (37%), in the submandibular gland in six (37%), in the para-aorta in three (19%), in the lung in three (19%), in mediastinal LNs in two (12%), and in the kidney in the case of two patients (12%). Asymmetrical accumulation in the submandibular gland was observed in three of six patients (50%) with IgG4-related disease and in none of the two patients (0%) with sarcoidosis. Significant differences were observed in the uptake ratio of the lacrimal gland, the submandibular gland, supraclavicular LNs, mediastinal LNs, pancreas, and muscle between the two groups (P<0.05). CONCLUSION: (67)Ga scintigraphy was useful in differentiating between the two diseases. Uptake in mediastinal LNs, in supraclavicular LNs, and in the muscle was specific to sarcoidosis, whereas uptake in the pancreas and in the submandibular gland indicated IgG4-related disease.

Pheochromocytoma in multiple endocrine neoplasia type 2A: positive 123I MIBG with negative CT and equivocal 131I MIBG imaging.

An 123I metaiodobenzylguanidine (MIBG) planar image showed abnormal uptake in the left adrenal gland and thyroid in a 24-year-old woman with multiple endocrine neoplasia type 2A. 131I MIBG showed abnormal uptake in the thyroid but not in the adrenal gland. Abdominal CT with 2-mm thin slices demonstrated a normal adrenal gland. Postoperative pathologic findings were consistent with medullary carcinoma in both thyroid lobes and a small 1-mm pheochromocytoma in the left adrenal gland. 123I MIBG could clearly show the small pheochromocytoma, which was negative in thin-slice CT and equivocal in 131I MIBG.

Hematoma after femoral arterial blood sampling: incidence, imaging features, and course of hematoma.

OBJECTIVE: This study evaluated the incidence and course of a hematoma occurring after femoral arterial sampling. MATERIALS AND METHODS: We studied 270 patients who underwent computed tomography (CT) including the pelvis and blood gas sampling from femoral artery using a 22-gauge needle during 2010. This population comprised 176 men and 94 women with a mean (SD) age of 54.9 (24.3) years (range, 0-97 years). We evaluated whether hematoma was present at the femoral artery. Size and location of the hematoma, the short-axial luminal diameter of artery contact with the hematoma was also assessed. RESULTS: The CT images showed hematoma around the femoral artery in 128 patients (47.4%); this group comprised 84 men and 44 women with a mean (SD) age of 51.1 (24.1) years (range, 0-92 years). Hematoma was not observed in 142 patients (52.6%; 92 men and 50 women; mean [SD] age, 58.3 [24.2] years; range, 0-97 years). There was no significant difference in age, sex, altered hemostasis, or time between arterial puncture and CT between the 2 groups with or without hematoma. Arterial stenosis of 50% or greater was observed in 7 patients (mean [SD] age, 17.1 [8.97] years; range, 6-31 years; 4 males and 3 females). CONCLUSIONS: Our data revealed a high frequency of small hematoma around the femoral artery is following arterial blood sampling that was independent of bleeding diathesis. No patient progressed to a severe condition, although temporary arterial stenosis did occur.

Tc-99m MAA findings in dilated cardiomyopathy with partial anomalous venous connections.

Tc-99m MAA showed asymmetric uptake in the lung field in a 21-year-old man with dilated cardiomyopathy. CT revealed partial anomalous venous connections in the left upper lobe. Angiogram of the left pulmonary upper lobe showed all the contrast material drained into the left vertical vein. The possible cause of relative increase in the left upper lobe blood flow is that right pulmonary blood flow is slowed by the high pressure in the left atrium due to dilated cardiomyopathy, whereas the flow from the left upper lobe drains into the superior vena cava which has less pressure than left atrium.

Whole-body gallium-67 scintigraphic findings in IgG4-related disease.

PURPOSE: To clarify the features of gallium-67 (Ga-67) imaging typical of IgG4-related disease. METHODS: We retrospectively investigated 14 patients diagnosed with IgG4-related disease who underwent Ga-67 scintigraphy in our hospital between January 2005 and May 2010. Of these, 13 patients who underwent gallium scintigraphy before steroid therapy were enrolled in this study. The patient population comprised 11 men and 2 women with age ranging from 47 to 76 years (mean age, 61.9 years). RESULTS: Among the 13 patients, significant accumulation of Ga-67 was detected in the bilateral pulmonary hila in 10 patients (77%), pancreas in 10 (77%), salivary glands in 7 (54%), lacrimal glands in 7 (54%), periaortic lesions in 2 (15%), and lung parenchyma in 1 (8%) patient. High accumulation of Ga-67 in the salivary glands was observed in the parotid glands in 3 cases and in the submandibular glands in 6 cases, with the following pattern: normal parotid gland uptake and symmetrical submandibular gland uptake in 2 cases; symmetrical high accumulation in both parotid and submandibular glands in 1 case; symmetrical high accumulation in parotid glands and normal submandibular gland uptake in 1 case; symmetrical uptake by parotid glands and asymmetric uptake by submandibular glands in 1 case; normal parotid gland uptake and asymmetric submandibular gland uptake in 1 case; and asymmetric parotid gland uptake and symmetrical parotid gland uptake in 1 case. CONCLUSION: Characteristic patterns of gallium uptake would be helpful for diagnosis, detection of involved lesions, and differential diagnosis in patients with IgG4-related disease to avoid unnecessary surgery.

Causes of photopenic defects in the lower sternum on bone scintigraphy and correlation with multidetector CT.

PURPOSE: To determine the cause of this photopenia in the lower sternum on bone scintigraphy and its correlation with sternal foramen on multidetector computed tomography (MDCT). METHODS: Between January and December 2008, we studied 1053 patients who underwent bone scintigraphy and CT scanning that included the chest. Bone scintigraphy showed photopenic areas in the lower sternum in 58 of these 1053 patients. The study population consisted of 19 men and 37 women, aged from 15 to 87 years (mean: 60.4 years). RESULTS: Of the 58 patients with photopenic areas in the lower sternum, 25 (43%) showed a sternal foramen by MDCT, whereas 33 patients (57%) showed no sternal foramen. However, of the total study population of 1053 patients, MDCT showed sternal foramen in 33 patients (3.1%). In 7 of the 33 patients with sternal foramen by MDCT, bone scintigraphy showed no photopenic areas. On the basis of CT morphometry of the sternum, the possible causes of photopenia in the lower sternum in patients without sternal foramen are as follows: thin middle portion of sternum bone marrow, a focal defect or notch in the posterior sternal cortex, high accumulation of peripheral lesions, and bone metastasis. CONCLUSION: This study revealed that not all patients showing photopenic areas in the lower sternum have sternal foramen and not all patients with sternal foramen show photopenic areas by bone scintigraphy. It is important to exclude metastasis when photopenic areas are detected, and inform the clinician to avoid the serious complication of cardiac tamponade.

Imaging findings at the donor site after iliac crest bone harvesting.

OBJECTIVE: Postoperative imaging after iliac crest bone harvesting is commonly performed, but has not been extensively reported in the literature. The objective of this analysis was to investigate the donor site after iliac crest graft harvesting. MATERIALS AND METHODS: Between January and December 2008, 3,450 patients underwent CT, which included the pelvis. Eighty-four patients were found whose iliac crests were harvested. The patient population consisted of 47 male and 37 female subjects ranging from 10 to 80 years old (mean 52.6 years) at the time of iliac bone harvesting. With the inclusion of prior examinations, 188 CT examinations, 17 MR imaging studies, and 19 bone scintigrams were analyzed at various time points after surgery. RESULTS: Computed tomography images demonstrated fluid collections, hematoma, and air at the donor site up to 1 month after bone harvesting. The air then disappeared. Fluid collection decreased in size by 4 months. Scar-like changes at the harvest site and irregular thick cortical bone were observed after 4 months. Later, CT and MR imaging demonstrated small scar-like lesions and cortical irregularities. CONCLUSION: The appearance of harvest site abnormalities depends on the time elapsed after surgery.

Comparison of Alzheimer's disease with vascular dementia and non-dementia using specific voxel-based Z score maps.

OBJECTIVE: We investigated the ability to discriminate between Alzheimer's disease (AD) and vascular dementia (VaD), and between AD and non-dementia using the program "easy Z score imaging system" (eZIS) developed by Matsuda et al., for the diagnosis of very early AD. METHODS: Of 201 patients, we investigated 12 patients with AD, 10 with VaD, and 9 with non-dementia, who underwent brain perfusion single-photon emission computed tomography by technetium-99m ethyl cysteinate dimer (99mTc-ECD) between February 2005 and September 2006. The sensitivity and specificity of the indicators of specific volume of interest (VOI) analysis, namely, severity, extent, and ratio were evaluated for the distinction of AD from VaD and non-dementia. RESULTS: There was a significant difference in all the criteria for severity, extent, and ratio between AD and non-dementia cases and in the ratio between AD and VaD. Between AD and non-dementia, the sensitivity and specificity of severity were 100% and 45%, respectively, using the cutoff value of 1.19. When using the cutoff value of 14.2 for extent, the sensitivity and specificity were both 100%. Using the cutoff value of 2.22 for ratio, the sensitivity of 42% and specificity of 100% were demonstrated. When comparing AD with VaD, using the cutoff value of 2.22 for ratio, the sensitivity and specificity were 42% and 100%, respectively. Using the cutoff value of 1.5 for ratio, the sensitivity and specificity between AD and VaD were 92% and 80%, respectively, thereby showing the best results. CONCLUSIONS: The specific VOI analysis program of AD using specific voxel-based Z score maps is not influenced by interobserver differences among radiologists and is useful to discriminate AD from VaD and non-dementia. However, the setting of the cutoff value at each institution and comparison with original and eZIS images are suggested to distinguish better AD from VaD.