Beyond Visual Assessment of Basal Ganglia Uptake: Can Automated Method and Pineal Body Uptake Assessment Improve Identification of Nigrostriatal Dysfunction on 18F-DOPA PET/CT?

The interpretation of 18F-DOPA PET/CT performed for assessing nigrostriatal dysfunction (NSD) is usually based on visual assessment of the uptake in the basal ganglia (VA-BG). In the present study, we evaluate the diagnostic performance of an automated method that assesses BG uptake (AM-BG) and of methods that assess pineal body uptake, and examine whether these methods can enhance the diagnostic performance of VA-BG alone. We retrospectively included 112 scans performed in patients with clinically suspected NSD who also had a subsequent final clinical diagnosis provided by a movement disorder specialist (69 NSD and 43 non-NSD patients). All scans were categorized as positive or negative based on (1) VA-BG, (2) AM-BG, and (3) qualitative and semiquantitative assessment of pineal body uptake. VA-BG, AM-BG, assessment of pineal body 18F-DOPA uptake by VA (uptake > background), by SUVmax (≥0.72), and by pineal to occipital ratio (POR ≥ 1.57) could all significantly differentiate NSD from non-NSD patients (Pv < 0.01 for all five methods). Of these methods, VA-BG provided the highest sensitivity (88.4%) and accuracy (90.2%). Combining VA-BG with AM-BG did not improve diagnostic accuracy. An interpretation algorithm that combines VA-BG with pineal body uptake assessment by POR calculation increased sensitivity to 98.5%, at the expense of decreased specificity. In conclusion, an automated method that assesses 18F-DOPA uptake in the BG and assessment of pineal body 18F-DOPA uptake can significantly separate NSD from non-NSD patients, with apparent inferior diagnostic performance when applied alone compared with VA-BG. When VA-BG categorizes a scan as negative or equivocal, assessment of the 18F-DOPA uptake in the pineal body has the potential to minimize the rate of false negative reports. Further research is essential to validate this approach and to study the pathophysiologic relationship between 18F-DOPA uptake in the pineal body and nigrostriatal dysfunction.

Aberrant dopamine transporter and functional connectivity patterns in LRRK2 and GBA mutation carriers.

Non-manifesting carriers (NMCs) of Parkinson's disease (PD)-related mutations such as LRRK2 and GBA are at an increased risk for developing PD. Dopamine transporter (DaT)-spectral positron emission computed tomography is widely used for capturing functional nigrostriatal dopaminergic activity. However, it does not reflect other ongoing neuronal processes; especially in the prodromal stages of the disease. Resting-state fMRI (rs-fMRI) has been proposed as a mode for assessing functional alterations associated with PD, but its relation to dopaminergic deficiency remains unclear. We aimed to study the association between presynaptic striatal dopamine uptake and functional connectivity (FC) patterns among healthy first-degree relatives of PD patients with mutations in LRRK2 and GBA genes. N = 85 healthy first-degree subjects were enrolled and genotyped. All participants underwent DaT and rs-fMRI scans, as well as a comprehensive clinical assessment battery. Between-group differences in FC within striatal regions were investigated and compared with striatal binding ratios (SBR). N = 26 GBA-NMCs, N = 25 LRRK2-NMCs, and N = 34 age-matched nonmanifesting noncarriers (NM-NCs) were included in each study group based on genetic status. While genetically-defined groups were similar across clinical measures, LRRK2-NMCs demonstrated lower SBR in the right putamen compared with NM-NCs, and higher right putamen FC compared to GBA-NMCs. In this group, higher striatal FC was associated with increased risk for PD. The observed differential SBR and FC patterns among LRRK2-NMCs and GBA-NMCs indicate that DaTscan and FC assessments might offer a more sensitive prediction of the risk for PD in the pre-clinical stages of the disease.

[METABOLIC AND DOPAMINERGIC BRAIN FUNCTIONAL IMAGING IN DEMENTIA WITH LEWY BODIES].

INTRODUCTION: Dementia with Lewy bodies (DLB) is the second most common neurodegenerative dementia of the elderly. Its early diagnosis is a clinical challenge due to overlapping symptoms of various neurodegenerative diseases. Early diagnosis is essential for patient management avoiding neuroleptic medications that harbor the risk of causing further deterioration. Functional imaging allows accurate diagnosis and improves the degree of confidence in the diagnosis. Its advantage is based on the ability to identify biochemical changes that precede structural changes, thereby providing valuable information at early stages of the disease. Another advantage is its ability to provide a non-invasive neurobiological evaluation as well as an objective follow-up algorithm. We present a patient with cognitive and motor decline, in which anatomical imaging (MRI) failed to recognize a specific morphological abnormality. Combined data of two PET-CT brain scans using two different radiotracers raised the diagnosis of DLB. Cortical metabolism was obtained by PET with labeled glucose (FDG) and the dopaminergic activity by labeled precursor (F-DOPA) of the neurotransmitter Dopamine. In times to come, with the development of novel specific tracers, diagnostic confidence is expected to improve, along with development of new approaches of therapy.

[18F] FDOPA PET may confirm the clinical diagnosis of Parkinson's disease by imaging the nigro-striatal pathway and the sympathetic cardiac innervation: Proof-of-concept study.

Autonomic involvement, including cardiac denervation, may precede the motor symptoms of Parkinson's disease by several years. L-3,4-dihydroxy-6-[18F] fluoro-phenylalanine is a positron emitter and a true analog of L-dopa, used in clinical practice to assess striatal dopaminergic integrity. The present study aimed to assess the feasibility of evaluating cardiac sympathetic denervation in Parkinson's disease patients using L-3,4-dihydroxy-6-[18F] fluoro-phenylalanine positron emission tomography/computed tomography. Patients referred for an L-3,4-dihydroxy-6-[18F] fluoro-phenylalanine positron emission tomography/computed-tomography between July 2015 and May 2017 to evaluate striatal presynaptic dopaminergic integrity underwent a heart positron emission tomography scan following a brain positron emission tomography scan. L-3,4-dihydroxy-6-[18F] fluoro-phenylalanine uptake in the left ventricle was quantified using CarimasT⁢M software and compared between patients with and without Parkinson's disease. The area under the receiver operating characteristic curve was used to evaluate the ability of the left ventricular mean standardized uptake value to discriminate between patients with Parkinson's disease and those with other extrapyramidal syndromes. Seventy-six patients were included, of whom 52 were diagnosed with Parkinson's disease. The mean L-3,4-dihydroxy-6-[18F] fluoro-phenylalanine left ventricular mean standardized uptake value was lower in the Parkinson's disease patients compared to the non- Parkinson's disease patients (1.08 ± 0.21 vs. 1.24 ± 0.32, P = 0.015). The left ventricular mean standardized uptake value was able to discriminate between Parkinson's disease and non- Parkinson's disease patients (the area under the receiver operating characteristic curve = 0.641, P = 0.049). In conclusion, quantification of cardiac L-3,4-dihydroxy-6-[18F] fluoro-phenylalanine uptake may be able to differentiate between patients with and without Parkinson's disease. Validation of this finding in more substantial, prospective trials are warranted.

Ga-PSMA PET/CT Staging of Newly Diagnosed Intermediate- and High-Risk Prostate Cancer.

BACKGROUND: Ga-prostate-specific membrane antigen positron emission tomography/computerized tomography (Ga-PSMA PET/CT) is part of the initial workup of patients with intermediate and high-risk prostate cancer provided by the Israeli national health services. OBJECTIVES: To assess the incidence of metastatic spread in consecutive patients with newly diagnosed cancer, and the potential added value of Ga-PSMA PET/CT to the staging imaging algorithm. METHODS: Patients with newly diagnosed intermediate- and high-risk prostate cancer were referred for initial staging by Ga-PSMA PET/CT between May 2016 and April 2017. Blood prostate-specific antigen (PSA) levels, clinical history, imaging reports and histopathological reports (including Gleason scores) were obtained. Maximal standardized uptake values (SUVmax) were determined for the primary lesions detected within the prostate. RESULTS: The study included 137 consecutive patients with intermediate- and high-risk disease who underwent Ga-PSMA PET/CT staging. Of these, 75 had Ga-PSMA uptake in both prostate lobes, 57 had unilateral uptake, and 5 patients had no uptake. SUVmax in the primary tumor correlated significantly with PSA levels. Thirty-five patients had increased uptake compatible with metastatic disease involving lymph nodes, bone, and viscera. Twenty-seven patients had available bone scintigraphy results: 18 (69%) of their 26 bone metastases detected by Ga-PSMA PET/CT were missed on bone scintigraphy. CONCLUSIONS: Ga-PSMA PET/CT shows promise as a sole whole-body imaging modality for assessing the presence of soft tissue and bone metastases in the setting of prostate cancer.

68Ga-PSMA is a novel PET-CT tracer for imaging of hepatocellular carcinoma: A prospective pilot study.

Background:68Ga-Prostate Specific Membrane Antigen (68Ga-PSMA), a positron emission tomography (PET) tracer that was recently introduce for imaging of prostate cancer, may accumulate in other solid tumors including Hepatocellular Carcinoma (HCC). The aim of the study was to assess the potential role of 68Ga-PSMA PET-Computed Tomography (CT) for imaging of HCC. Material and Methods: A prospective pilot study in seven patients with HCC with 41 liver lesions: 37 suspected malignant lesions (tumor lesions) and 4 regenerative nodules. For each liver lesion, uptake of 68Ga-PSMA and 18F-FDG uptake were measured [standard uptake value (SUV) and lesion-to-liver background ratios (TBR-SUV)], and correlated with dynamic characteristics (HU and TBR-HU) obtained on contrast enhanced CT data. Immunohistochemistry staining of PSMA in the tumor tissue was analyzed in samples obtained from 5 patients with HCC and compared to control samples from 3 patients with prostate cancer. Results: Thirty-six of the 37 tumor lesions and none of the regenerative nodules showed increased 68Ga-PSMA uptake while only 10 lesions were 18F-FDG avid. Based on contrast enhancement, tumor lesions were categorized into 27 homogeneously enhancing lesions, nine lesions with "mosaic" enhancement composed of enhancing and non-enhancing regions in the same lesion and a single non-enhancing lesion, the latter being the only non-68Ga-PSMA avid lesion. Using the Mann-Whitney test, 68Ga-PSMA uptake was found significantly higher in enhancing tumor areas compared to non-enhancing areas and in contrast, 18F-FDG uptake was higher in non-enhancing areas, P<0.001 for both. 68Ga-PSMA uptake (TBR SUVmax) was found to correlate with vascularity (TBR-HU) (Spearman r=0.866, p<0.001). Immunohistochemistry showed intense intra-tumoral microvessel staining for PSMA in HCC, in contrast with cytoplasmic and membranous staining, mainly in the luminal border, in prostate cancer samples. In two of the study patients 68Ga-PSMA PET-CT identified unexpected extrahepatic metastases. Four regenerative liver nodules showed no increased uptake of either of the PET tracers. Conclusion:68Ga-PSMA PET-CT is superior to 18F-FDG PET-CT in imaging patients with HCC. HCC lesions are more commonly hypervascular taking up 68Ga-PSMA in tumoral micro-vessels. 68Ga-PSMA PET-CT is a potential novel modality for imaging patients with HCC.

FDG PET Parkinson's disease-related pattern as a biomarker for clinical trials in early stage disease.

Background: The development of therapeutic interventions for Parkinson disease (PD) is challenged by disease complexity and subjectivity of symptom evaluation. A Parkinson's Disease Related Pattern (PDRP) of glucose metabolism via fluorodeoxyglucose positron emission tomography (FDG-PET) has been reported to correlate with motor symptom scores and may aid the detection of disease-modifying therapeutic effects. Objectives: We sought to independently evaluate the potential utility of the PDRP as a biomarker for clinical trials of early-stage PD. Methods: Two machine learning approaches (Scaled Subprofile Model (SSM) and NPAIRS with Canonical Variates Analysis) were performed on FDG-PET scans from 17 healthy controls (HC) and 23 PD patients. The approaches were compared regarding discrimination of HC from PD and relationship to motor symptoms. Results: Both classifiers discriminated HC from PD (p < 0.01, p < 0.03), and classifier scores for age- and gender- matched HC and PD correlated with Hoehn & Yahr stage (R2 = 0.24, p < 0.015) and UPDRS (R2 = 0.23, p < 0.018). Metabolic patterns were highly similar, with hypometabolism in parieto-occipital and prefrontal regions and hypermetabolism in cerebellum, pons, thalamus, paracentral gyrus, and lentiform nucleus relative to whole brain, consistent with the PDRP. An additional classifier was developed using only PD subjects, resulting in scores that correlated with UPDRS (R2 = 0.25, p < 0.02) and Hoehn & Yahr stage (R2 = 0.16, p < 0.06). Conclusions: Two independent analyses performed in a cohort of mild PD patients replicated key features of the PDRP, confirming that FDG-PET and multivariate classification can provide an objective, sensitive biomarker of disease stage with the potential to detect treatment effects on PD progression.

Assessment of Residual Disease With Molecular Breast Imaging in Patients Undergoing Neoadjuvant Therapy: Association With Molecular Subtypes.

BACKGROUND: Assessment of residual disease after neoadjuvant therapy for breast cancer is an ongoing challenge of breast imaging. This study evaluates the accuracy of a novel dedicated system for molecular breast imaging (MBI) composed of the new generation of cadmium zinc telluride detectors in assessing residual disease after neoadjuvant therapy in patients with breast cancer. PATIENTS AND METHODS: Clinical data, imaging, surgical, and pathological findings of 51 women with breast cancer undergoing neoadjuvant therapy were recorded. MBI findings were correlated with surgical pathology results. Accuracy of MBI in predicting complete pathological response and size of residual disease was assessed according to molecular subtypes. RESULTS: The size of the largest focus of uptake on MBI correlated with the largest dimension measured on pathology (r = 0.55; P < .001). This correlation was stronger for triple negative and HER2/neu positive subtypes (r = 0.92 and 0.62, respectively). Sixteen patients (31%) had complete pathological response. The sensitivity and specificity of MBI for detecting residual disease were 83% (95% confidence interval [CI], 66-93) and 69% (95% CI, 42-88), respectively. For triple negative or HER2/neu positive disease the sensitivity and specificity were 88% (95% CI, 62-98) and 75% (95% CI, 43-93), respectively. CONCLUSION: The accuracy of MBI in assessing residual disease after neoadjuvant treatment might be related to the molecular subtype. Accuracy is highest in the triple negative and HER2/neu positive subtypes.

Breast Imaging Utilizing Dedicated Gamma Camera and (99m)Tc-MIBI: Experience at the Tel Aviv Medical Center and Review of the Literature Breast Imaging.

The scope of the current article is the clinical role of gamma cameras dedicated for breast imaging and (99m)Tc-MIBI tumor-seeking tracer, as both a screening modality among a healthy population and as a diagnostic modality in patients with breast cancer. Such cameras are now commercially available. The technology utilizing a camera composed of a NaI (Tl) detector is termed breast-specific gamma imaging. The technology of dual-headed camera composed of semiconductor cadmium zinc telluride detectors that directly converts gamma-ray energy into electronic signals is termed molecular breast imaging. Molecular breast imaging system has been installed at the Department of Nuclear medicine at the Tel Aviv Sourasky Medical Center, Tel Aviv in 2009. The article reviews the literature well as our own experience.

The Value of PET/CT in Detecting Bone Marrow Involvement in Patients With Follicular Lymphoma.

Follicular lymphoma (FL) is the 2nd most common type of lymphoma diagnosed in the Western World. Bone marrow (BM) involvement is an adverse prognostic factor in FL, routinely assessed by an arbitrary biopsy of the iliac crest. This study was aimed to investigate the role of positron emission tomography/computed tomography (PET/CT) in identifying BM involvement by FL. In this retrospective, single-center study we reviewed the records of consecutive patients with FL at diagnosis or relapse who underwent staging/restaging workup visual assessment of BM uptake was categorized as either normal, diffusely increased, or focally increased. Quantitative BM fluorine-18-fluro-deoxyglucose (FDG) uptake was measured using mean standardized uptake value (BM-SUVmean). The diagnosis of BM involvement was based on either BM histological findings or disappearance of increased uptake at end-treatment PET/CT in patients who responded to treatment. Sixty eight cases with FL were included. Sixteen (23.5%) had BM involvement, 13 (19.1%) had a biopsy proven involvement, and 3 (4.4%) had a negative BM biopsy, but increased medullary uptake that normalized post-treatment. BM FDG uptake in these patients was diffuse in 8 (50%) and focal in 8 (50%). Focal increased uptake was indicative of BM involvement; however, diffuse uptake was associated with 17 false positive cases (32.7%). Overall, visual assessment of BM involvement had a negative predictive value (NPV) of 100% and a positive predictive value (PPV) of 48.5%. On a quantitative assessment, BM-SUVmean was significantly higher in patients with BM involvement (SUVmean of 3.7 [1.7-6] vs 1.4 [0.4-2.65], P < 0.001). On receiver operator curve (ROC) analysis, BM-SUVmean > 2.7 had a PPV of 100% for BM involvement (sensitivity of 68%), while BM-SUVmean < 1.7 had an NPV of 100% (specificity of 73%). Visual assessment of PET/CT is appropriate for ruling out BM involvement by FL. Although focal increased uptake indicates marrow involvement, diffuse uptake is nonspecific. SUV measurement improves PET/CT diagnostic accuracy, identifying additional 19% of patients with BM involvement that would have been otherwise missed.

(99m)Tc-MDP bone scintigraphy of the hand: comparing the use of novel cadmium zinc telluride (CZT) and routine NaI(Tl) detectors.

BACKGROUND: Cadmium zinc telluride (CZT) solid-state detectors have been recently introduced in the field of nuclear medicine in cardiology and breast imaging. The aim of the current study was to evaluate the performance of the novel detectors (CZT) compared to that of the routine NaI(Tl) in bone scintigraphy. A dual-headed CZT-based camera dedicated originally to breast imaging has been used, and in view of the limited size of the detectors, the hands were chosen as the organ for assessment. This is a clinical study. METHODS: Fifty-eight consecutive patients (total 116 hands) referred for bone scan for suspected hand pathology gave their informed consent to have two acquisitions, using the routine camera and the CZT-based camera. The latter was divided into full-dose full-acquisition time (FD CZT) and reduced-dose short-acquisition time (RD CZT) on CZT technology, so three image sets were available for analysis. Data analysis included comparing the detection of hot lesions and identification of the metacarpophalangeal, proximal interphalangeal, and distal interphalangeal joints. RESULTS: A total of 69 hot lesions were detected on the CZT image sets; of these, 61 were identified as focal sites of uptake on NaI(Tl) data. On FD CZT data, 385 joints were identified compared to 168 on NaI(Tl) data (p < 0.001). There was no statistically significant difference in delineation of joints between FD and RD CZT data as the latter identified 383 joints. CONCLUSIONS: Bone scintigraphy using a CZT-based gamma camera is associated with improved lesion detection and anatomic definition. The superior physical characteristics of this technique raised a potential reduction in administered dose and/or acquisition time without compromising image quality.

Estrogen-dependent variations in 18F-fluorodeoxyglucose uptake in uterine leiomyomas.

OBJECTIVE: Positron emission tomography/computed tomography (PET/CT) is an important tool in oncology for assessment of disease extent and recurrence. Recognition of benign fluorodeoxyglucose (FDG) uptake promotes correct interpretation of imaging data. This study assesses the appearance of benign uterine leiomyomas (ULs) on PET/CT and evaluates possible hormonal influences. PATIENTS AND METHODS: This was a retrospective study performed in a tertiary referral cancer center in Israel. One hundred fifty-two women with nongynecologic malignancies were referred for PET/CT scans, with incidental UL on imaging. Information on menopausal status and menstrual phase and on the use of oral contraceptives, hormone replacement therapy, and selective estrogen receptor modulators (SERM) was collected. Fluorodeoxyglucose uptake measured as standard uptake value (SUV) was obtained for UL, normal myometrium, and gluteus muscle. Changes associated with menopausal status, menstrual cycle phase, and the use of oral contraceptives, hormone replacement therapy, and SERM were assessed. RESULTS: The mean ± SD SUV in UL for the entire cohort was 1.39 ± 0.65 and was higher than in myometrium (1.24 ± 0.33) and gluteus muscle (0.48 ± 0.36). Fluorodeoxyglucose uptake was similar in UL and in myometrium during the preovulatory (1.42 ± 0.31 vs. 1.23 ± 0.34) and postovulatory (1.23 ± 0.34 vs. 1.38 ± 0. 4) periods. During ovulation, SUV was significantly higher in UL (1.62 ± 0.39) than in normal myometrium (1.12 ± 0.15; P = 0.01). Uterine leiomyoma FDG uptake in premenopausal women (1.47 ± 0.32) was higher than in postmenopausal women (1.29 ± 0.41; P < 0.02). The UL/gluteus SUV ratio in patients on hormone replacement therapy (2.53 ± 0.23) was significantly higher than in untreated patients (1.27 ± 0.92; P = 0.05). Lower uptake was recorded in patients on SERM (SUV, 1.1 ± 0.24) than in untreated patients (SUV, 1.41 ± 0.36; P < 0.01). CONCLUSION: Fluorine 18 FDG uptake in UL may be estrogen dependent. Endogenous estrogen and hormone replacement therapy increase FDG uptake, whereas withdrawal of estrogen by menopause or SERM decreases uptake.

Brain imaging study of the acute effects of Delta9-tetrahydrocannabinol (THC) on attention and motor coordination in regular users of marijuana.

PROCEDURE: Twelve regular users of marijuana underwent two positron emission tomography (PET) scans using [18F] Fluorodeoxyglucose (FDG), one while subject to the effects of 17 mg THC, the other without THC. In both sessions, a virtual reality maze task was performed during the FDG uptake period. RESULTS: When subject to the effects of 17 mg THC, regular marijuana smokers hit the walls more often on the virtual maze task than without THC. Compared to results without THC, 17 mg THC increased brain metabolism during task performance in areas that are associated with motor coordination and attention in the middle and medial frontal cortices and anterior cingulate, and reduced metabolism in areas that are related to visual integration of motion in the occipital lobes. CONCLUSION: These findings suggest that in regular marijuana users, the immediate effects of marijuana may impact on cognitive-motor skills and brain mechanisms that modulate coordinated movement and driving.

Sentinel node-guided evaluation of drainage patterns for melanoma of the helix of the ear.

The head and neck region, and especially the ear and its helix, is notorious for its ambiguous pattern of lymphatic drainage. Therefore, the primary nodal drainage basins in melanoma of the helix of the ear are often unpredictable. The aim of the study was to examine the value of sentinel lymph node biopsy in melanoma of the helix of the ear and to describe the natural history of the disease. Fifteen consecutive patients (14 men) with primary melanoma of the helix of the ear (median thickness, 1.2 mm; range, 0.7-10.0) underwent preoperative lymphoscintigraphy, followed by intraoperative lymphatic mapping, using blue dye in combination with a hand-held gamma probe and sentinel lymphadenectomy. The melanomas were characterized by low mitotic rate, low lymphocytic infiltrate, low spontaneous-regression rate, and mostly epitheloid cell type. In one patient, preoperative lymphoscintigraphy failed to demonstrate the draining nodes. The sentinel lymph nodes were identified and retrieved in all patients during surgery. In 13 patients (87%), they were found in the upper jugular lymphatic basin (level IIA); none were found in the retroauricular region. All sentinel lymph nodes were tumor-negative. At a median follow-up of 39 months (range, 12-73), all 15 patients were disease-free. In conclusion, sentinel lymph node biopsy for helix melanoma is an excellent alternative to elective lymph node neck dissection and superficial parotidectomy, with a high success rate and low morbidity. Melanoma of the helix of the ear has an indolent natural history.

Benign nonphysiologic lesions with increased 18F-FDG uptake on PET/CT: characterization and incidence.

OBJECTIVE: The objective of our study was to characterize benign lesions showing increased 18F-FDG uptake and to determine their incidence on whole-body FDG PET/CT performed in oncologic patients. In addition, the performance of PET alone and PET/CT in characterizing lesions as benign was compared. MATERIALS AND METHODS: A retrospective review of 1,134 consecutive reports of PET/CT studies performed in patients with proven or suspected malignancy over a 6-month period yielded 289 patients with 313 lesions that showed increased FDG uptake but were suspected to be benign (nonphysiologic) or indeterminate. Lesions were subjectively categorized on the basis of the intensity of FDG uptake (mild, moderate, or marked) as compared with background activity. For each lesion, a decision was made as to whether a benign diagnosis could be obtained by the CT part of the study, the PET pattern, or clinical correlation, or whether histologic sampling was necessary. The performance of PET alone and PET/CT for characterizing lesions as benign was compared. Two hundred twenty-nine of the lesions were assessed further: 210 were benign and 19, malignant. The final diagnosis was determined by pathology (n = 67), PET/CT follow-up (n = 58), correlative imaging (n = 59), clinical correlation (n = 32), or typical benign pattern on PET/CT (n = 13). RESULTS: The causes for benign uptake of FDG were inflammatory processes (n = 154, 73.3%), benign tumors (n = 23, 11%), hematoma or seroma (n = 17, 8.1%), fracture (n = 7, 3.3%), fat necrosis (n = 3, 1.4%), and others (n = 6, 2.9%). For lesions with moderate or marked uptake of FDG (n = 117, 55.7%), a benign diagnosis could have been suggested on either PET or CT (e.g., a "hot" osteophyte) in 33 lesions (28.2%), on CT alone (e.g., peritoneal fat necrosis) in 38 lesions (32.5%), on PET alone (e.g., sialadenitis) in 10 lesions (8.5%), or by clinical correlation (e.g., dental abscess) in four lesions (3.4%). A benign diagnosis could not be established without histology (e.g., colonic polyp) in 32 lesions (27.4%). The performance of PET/CT was superior to that of PET alone in characterizing lesions as benign (p < 0.001). CONCLUSION: Benign lesions with increased FDG uptake are found in more than 25% of the PET/CT studies performed in patients with proven or suspected malignancy, with inflammation being the most common cause. Lesion characterization on the CT portion of the PET/CT study increases the specificity of PET/CT reporting, especially for lesions with moderate or marked FDG uptake.

Fluorine-18 fluorodeoxyglucose PET/CT patterns of extranodal involvement in patients with Non-Hodgkin lymphoma and Hodgkin's disease.

Lymphoma may originate in extranodal sites. Extranodal lymphoma may also be secondary to and accompany nodal disease. Fluorine-18 fluorodeoxyglucose (18F-FDG) imaging has an essential role in the staging of lymphoma, in monitoring the response to therapy, and in detection of recurrence. The introduction of 18F-FDG PET/CT hybrid imaging allows for accurate localization of disease and may be specifically beneficial for the detection of unexpected extranodal sites of disease or exclusion of disease in the presence of nonspecific extranodal CT findings. Accurate staging and localization often dictate the appropriate treatment strategy in patients with lymphoma. Therefore, at any stage in the course of the disease, the potential presence of extranodal disease should be considered when interpreting 18F-FDG PET/CT studies in patients with non-Hodgkin lymphoma and Hodgkin's disease.

Improved sentinel node identification by SPECT/CT in overweight patients with breast cancer.

UNLABELLED: Overweight has been reported as a cause for the nonvisualization of sentinel nodes (SNs) on preoperative planar lymphoscintigraphy in patients with breast cancer. The purpose of this study was to assess whether SPECT/CT may improve SN identification in overweight patients. METHODS: Lymphoscintigraphy was performed in 220 consecutive patients with breast cancer. Body mass index (BMI) was calculated for each. A total of 122 patients were overweight or obese (BMI, > or = 25). Planar images and SPECT/CT images were interpreted separately, and SN identification on each of the modalities was related to BMI and to findings at surgery. RESULTS: Planar imaging identified SNs in 171 patients (78%) with a BMI (mean +/- SD) of 25.2 +/- 4 kg/m2 and failed to do so in 49 patients (22%) with a BMI of 28 +/- 8 kg/m2. In 29 of the latter patients (59%), SNs were identified on SPECT/CT. SPECT/CT detected "hot" nodes in 200 patients (91%) and failed to do so in 20 patients with a BMI of 29.2 +/- 6.6 kg/m2. For the 122 overweight or obese patients, planar assessment failed to identify SNs in 34 patients (28%) and SPECT/CT failed to do so in 13 patients (11%) (P < 0.001). For 116 patients, surgery took place in our hospital (Tel-Aviv Sourasky Medical Center). An intraoperative blue dye technique failed to detect SNs in 48 patients (41%) with a BMI of 28.2 +/- 7 kg/m2. SPECT/CT localized hot nodes in 36 (75%) of the latter patients, and planar imaging did so in 22 (46%) of those patients. Of 19 patients for whom scintigraphy failed, 6 (32%) had nodal metastatic involvement. CONCLUSION: The addition of SPECT/CT to lymphoscintigraphy improved SN identification in overweight patients with breast cancer. Moreover, SPECT/CT accurately identified SNs in 75% of patients for whom the identification of SNs by the intraoperative blue dye technique failed.

SPECT/multislice low-dose CT: a clinically relevant constituent in the imaging algorithm of nononcologic patients referred for bone scintigraphy.

UNLABELLED: The purpose of this prospective study was to assess the role of SPECT/multislice low-dose (Msl) CT as a constituent in the imaging algorithm of nononcologic patients referred for 99mTc-methylene diphosphonate bone scintigraphy (BS). METHODS: SPECT/CT was performed using a novel hybrid system, which incorporates a gamma-camera and a multislice low-dose CT, on 76 consecutive nononcologic patients with nonspecific scintigraphic findings, which required further correlation with morphologic data. RESULTS: SPECT/MslCT was of added clinical value in 89% of the patients. Characterizing scintigraphic lesions by their morphologic appearance, SPECT/MslCT reached a final diagnosis in 49 of 85 (58%) nonspecific scintigraphic bone lesions found in 59% (45/76) of patients, obviating the need to perform additional imaging. In another 30% of patients (23/76), SPECT/MslCT data optimized the patients' imaging algorithm as the performance of a full-dose CT, MRI, or labeled-leukocyte scintigraphy as the next imaging was based on its findings combined with the patient's clinical presentation. CONCLUSION: SPECT/MslCT is a clinically relevant constituent in the imaging algorithm of nononcologic patients referred for BS.

Lymphoscintigraphy for sentinel node mapping using a hybrid single photon emission CT (SPECT)/CT system in oral cavity squamous cell carcinoma.

BACKGROUND: We assessed the added clinical value of fused single photon emission computed tomography (SPECT) and low-dose CT images compared with planar images for sentinel node (SN) mapping in patients with oral cavity squamous cell carcinoma (SCC). METHODS: Twenty consecutive patients with newly diagnosed biopsy-proven SCC of the oral cavity were enrolled. Scintigraphy was performed using a hybrid gamma-camera/low-dose CT system. Planar images and fused SPECT/CT images were interpreted separately. All patients underwent a sentinel node biopsy (SNB) followed by a neck dissection. All SNs underwent meticulous pathologic examination and immunohistochemistry staining (cytokeratin complex) in addition to routine pathologic examinations of the neck dissection specimen. RESULTS: The sensitivity for the detection of nodal metastases was 87.5%. SPECT/CT improved SN identification and/or localization compared with planar images in 6 patients (30%). CONCLUSIONS: SPECT/CT SN mapping provides additional preoperative data of clinical relevance to SNB in patients with oral cavity SCC.