Follow-up Positron Emission Tomography Scan Research Articles

Plasma Leptin and Alzheimer Protein Pathologies Among Older Adults

Many epidemiologic studies have suggested that low levels of plasma leptin, a major adipokine, are associated with increased risk of Alzheimer disease (AD) dementia and cognitive decline. Nevertheless, the mechanistic pathway linking plasma leptin and AD-related cognitive decline is not yet fully understood. To examine the association of plasma leptin levels with in vivo AD pathologies, including amyloid-beta (Aβ) and tau deposition, through both cross-sectional and longitudinal approaches among cognitively unimpaired older adults. This was a longitudinal cohort study from the Korean Brain Aging Study for Early Diagnosis and Prediction of Alzheimer Disease. Data were collected from January 1, 2014, to December 31, 2020, and data were analyzed from July 11 to September 6, 2022. The study included a total of 208 cognitively unimpaired participants who underwent baseline positron emission tomography (PET) scans for brain Aβ deposition. For longitudinal analyses, 192 participants who completed both baseline and 2-year follow-up PET scans for brain Aβ deposition were included. Plasma leptin levels as assessed by enzyme-linked immunosorbent assay. Baseline levels and longitudinal changes of global Aβ and AD-signature region tau deposition measured by PET scans. Among the 208 participants, the mean (SD) age was 66.0 (11.3) years, 114 were women (54.8%), and 37 were apolipoprotein E ε4 carriers (17.8%). Lower plasma leptin levels had a significant cross-sectional association with greater brain Aβ deposition (β = -0.04; 95% CI, -0.09 to 0.00; P = .046), while there was no significant association between plasma leptin levels and tau deposition (β = -0.02; 95% CI, -0.05 to 0.02; P = .41). In contrast, longitudinal analyses revealed that there was a significant association between lower baseline leptin levels and greater increase of tau deposition over 2 years (β = -0.06; 95% CI, -0.11 to -0.01; P = .03), whereas plasma leptin levels did not have a significant association with longitudinal change of Aβ deposition (β = 0.006; 95% CI, 0.00-0.02; P = .27). The present findings suggest that plasma leptin may be protective for the development or progression of AD pathology, including both Aβ and tau deposition.

Anti-Ma2 Antibody-Mediated Paraneoplastic Cerebellar Degeneration and Myeloneuropathy Secondary to Lymphoma.

A 61-year-old woman with a history of untreated low-grade B-cell lymphoma presented with blurry vision, unsteadiness, and worsening pain on touching skin of the upper trunk was enrolled. Blurry vision was attributed to oscillopsia from downbeat nystagmus, which later evolved into macrosaccadic oscillations. MRI brain and spine showed mild, longitudinally extensive T2 hyperintensity in the central gray matter of the spinal cord extending from the medulla to T11 level. Serum paraneoplastic panel was negative; however, she had very high titers of anti-Ma2 antibodies in cerebrospinal fluid. The diagnosis of paraneoplastic neurological syndrome was made. Empiric treatment with high dose of intravenous steroids followed by intravenous immunoglobulin infusions did not improve her symptoms. An extensive search for an underlying tumor commenced and was initially unrevealing. However, two-month follow-up positron emission tomography scan showed increased uptake in a right pulmonary nodule, which when biopsied confirmed diagnosis of extranodal marginal zone lymphoma. The final diagnosis was anti-Ma2 antibody-mediated paraneoplastic cerebellar degeneration and myeloneuropathy secondary to lymphoma.

Positron emission tomography assessment of metacarpal/metatarsal condylar fractures post surgical repair: Prospective study in 14 racehorses.

To assess 18F-sodium fluoride (18F-NaF) positron emission tomography (PET) findings associated with metacarpal/metatarsal condylar fractures at the time of fracture repair and through healing. Prospective descriptive study. Fourteen Thoroughbred racehorses. 18F-NaF PET was performed within 4 days of surgical metacarpal/metatarsal condylar fracture repair, on both the injured and contralateral limb. Follow-up PET scans were offered at 3- and 5-months post fracture repair. Areas of abnormal uptake were assessed using a previously validated grading system. Eight fractures were located in the parasagittal groove (PSG) (six lateral and two medial) and six fractures were located abaxial to the PSG (non-PSG) through the palmar/plantar condyle (all lateral). All horses in the latter group had uptake in the lateral palmar condyle of the contralateral limb suggestive of stress remodeling. Three horses with PSG fractures had uptake in a similar location in the contralateral limb. Horses with lateral condylar fracture only presented minimal or mild uptake in the medial condyle, which is considered atypical in the front limbs for horses in full training. Four horses developed periarticular uptake in the postoperative period suggestive of degenerative joint disease, three of these horses had persistent uptake at the fracture site. These four horses did not return to racing successfully. The findings of this study provide evidence of pre-existing lesions and specific uptake patterns in racehorses suffering from metacarpal/metatarsal condylar fractures. PET has a possible role in the prevention, diagnosis, and postoperative monitoring of metacarpal/metatarsal condylar fractures in racehorses.

Danish study of Non-Invasive Testing in Coronary Artery Disease 3 (Dan-NICAD 3): study design of a controlled study on optimal diagnostic strategy

IntroductionCurrent guideline recommend functional imaging for myocardial ischaemia if coronary CT angiography (CTA) has shown coronary artery disease (CAD) of uncertain functional significance. However, diagnostic accuracy of selective myocardial perfusion...

Quantitative PET tracking of intra-articularly administered 89Zr-peptide-decorated nanoemulsions.

Intra-articular (IA) administration of drugs for the treatment of diseases such as rheumatoid arthritis, osteoarthritis and psoriatic arthritis is a common strategy; however, the rapid clearance from the synovial fluid restricts their effectivity due to the limited retention time. Drug Delivery Systems (DDS) are currently being developed to increase their joint retention time. This study compares the biodistribution and retention time of a senolytic peptide (PEP), with potential application in osteoarthritis disease, and this senolytic peptide encapsulated in a DDS based on a lipid nanoemulsion (PEPNE) by using positron emission tomography (PET) imaging. To this aim, the PEP was conjugated with a chelating agent (DFO) and radiolabeled with zirconium-89 (89Zr). Then, [89Zr]-PEP was encapsulated in a novel nanoemulsion formulation, composed by vitamin E, sphingomyelin, and a lipid-PEG. Afterward, healthy rats were administered with either the [89Zr]-PEP or the [89Zr]-PEP-NE via IA injection and underwent PET scans at 0.5-, 24-, 48-, 72-, 168-, 240- and 336h post-injection. To assess the biodistribution of both radiotracers, several volume-of-interest were manually drawn in different organs of the rat body and the %ID/organ was calculated. The [89Zr]-PEP was successfully encapsulated in the NE and their physicochemical properties were minimally affected by the radiolabeling buffer. Adequate stability of both [89Zr]-PEP and [89Zr]-PEP-NE was found in synovial fluid over 72h. Quantitative data from PET images revealed a significantly higher [89Zr]-PEP-NE retention in the injected knee than with [89Zr]-PEP in all follow-up PET scans. The [89Zr]-PEP %ID/organ values in the liver and kidney were significantly higher than those from [89Zr]-PEP-NE, which might indicate a faster elimination of the [89Zr]-PEP. Therefore, the study highlights the higher retention time on the target site of the [89Zr]-PEP-NE which may improve the therapeutic effects of the peptide. Thereby, the novel nanoemulsion formulation seems to be a successful DDS for IA injection. In addition, these results represent the first study that evaluates the distribution of a PET-guided DDS after its IA administration.

Validation of Deauville Score for Response Evaluation in Hodgkin's Lymphoma.

Positron emission tomography (PET) using F-18 fluorodeoxyglucose (FDG) for treatment monitoring in patients with lymphoma is one of the most well-developed clinical applications. Deauville five-point score (DS) is recommended for response assessment in international guidelines. DS gives the threshold for adequate or inadequate response to be adapted according to the clinical context or research question. We aimed to validate DS in Hodgkin's lymphoma (HL) by retrospectively assigning this score to F-18 FDG PET-computed tomography (CT) studies done before 2016 and analyzing its concordance with the line of management. The secondary aim was to assess the reproducibility of DS in the interpretation of PET-CT scans. A total of 100 eligible consecutive patients underwent F-18 FDG PET-CT scans between January 2014 and December 2015. Their interim, end of treatment, and follow-up PET scans were retrospectively visually analyzed and assigned DS by three nuclear medicine physicians. Concordance was defined as agreement between the DS assigned and the line of treatment. Interobserver variability was calculated using weighted Kappa and presented with 95% confidence interval. Among 212 scans assigned DS, 165 scans showed agreement between the DS and line of treatment. Of these, 95.2% of scans scored DS 1-3 were kept on following or the same treatment plan was continued and patients did well. Among the scans that showed discordance, 24 scans scored DS 4/5 were continued on the same treatment regimen and the next assessment showed disease progression. Our study confirmed that DS is a useful tool to aid in reporting F-18 FDG PET-CT in the management of HL with good positive and negative predictive values. This study also demonstrated good interobserver agreement.

Effects of Bilateral Subthalamic Nucleus Stimulation on Depressive Symptoms and Cerebral Glucose Metabolism in Parkinson's Disease: A 18F-Fluorodeoxyglucose Positron Emission Tomography/Computerized Tomography Study.

Subthalamic nucleus (STN) deep brain stimulation (DBS) can improve motor symptoms in Parkinson’s disease (PD), as well as potentially improving otherwise intractable comorbid depressive symptoms. To address the latter issue, we evaluated the severity of depressive symptoms along with the severity of motor symptoms in 18 PD patients (mean age, 58.4 ± 5.4 years; 9 males, 9 females; mean PD duration, 9.4 ± 4.4 years) with treatment-resistant depression (TRD) before and after approximately 1 year of STN-DBS treatment. Moreover, to gain more insight into the brain mechanism mediating the therapeutic action of STN-DBS, we utilized 18F-fluorodeoxyglucose (FDG) positron emission tomography (PET) to assess cerebral regional glucose metabolism in the patients at baseline and 1-year follow-up. Additionally, the baseline PET data from patients were compared with PET data from an age- and sex-matched control group of 16 healthy volunteers. Among them, 12 PD patients underwent post-operative follow-up PET scans. Results showed that the severity of both motor and depressive symptoms in patients with PD-TRD was reduced significantly at 1-year follow-up. Also, patients used significantly less antiparkinsonian medications and antidepressants at 1-year follow-up, as well as experiencing improved daily functioning and a better quality of life. Moreover, relative to the PET data from healthy controls, PD-TRD patients displayed widespread abnormalities in cerebral regional glucose metabolism before STN-DBS treatment, which were partially recovered at 1-year follow-up. Additionally, significant correlations were observed between the patients’ improvements in depressive symptoms following STN-DBS and post-operative changes in glucose metabolism in brain regions implicated in emotion regulation. These results support the view that STN-DBS provides a promising treatment option for managing both motor and depressive symptoms in patients who suffer from PD with TRD. However, the results should be interpreted with caution due to the observational nature of the study, small sample size, and relatively short follow-up.

Association of Initial β-Amyloid Levels With Subsequent Flortaucipir Positron Emission Tomography Changes in Persons Without Cognitive Impairment

Tau accumulation in Alzheimer disease (AD) is closely associated with cognitive impairment. Quantitating tau accumulation by positron emission tomography (PET) will be a useful outcome measure for future clinical trials in the AD spectrum. To investigate the association of β-amyloid (Aβ) on PET with subsequent tau accumulation on PET in persons who were cognitively unimpaired (CU) to gain insight into temporal associations between Aβ and tau accumulation and inform clinical trial design. This cohort study included individuals aged 65 to 85 years who were CU and had participated in the Mayo Clinic Study of Aging, with serial cognitive assessments, serial magnetic resonance imaging, 11C-Pittsburgh compound B (Aβ) PET scans, and 18F-flortaucipir PET scans, collected from May 2015 to March 2020. Persons were excluded if they lacked follow-up PET scans. A similarly evaluated CU group from the Alzheimer's Disease Neuroimaging Initiative (ADNI) were also studied. These data were collected from September 2015 to March 2020. Participants were stratified by index Aβ levels on PET into low Aβ (≤8 centiloid [CL]), subthreshold Aβ (9-21 CL), suprathreshold Aβ (22-67 CL), and high Aβ (≥68 CL). Changes over a mean of 2.7 (range, 1.1-4.1) years in flortaucipir PET in entorhinal, inferior temporal, and lateral parietal regions of interest and an AD meta-region of interest (ROI). A total of 167 people were included (mean age, 74 [range, 65-85] years; 75 women [44.9%]); 101 individuals were excluded lacking follow-up, and 114 individuals from the ADNI were also studied (mean [SD] age, 74.14 [5.29] years; 64 women [56.1%]). In the Mayo Clinic Study of Aging, longitudinal flortaucipir accumulation rates in the high Aβ group were greater than the suprathreshold, subthreshold, and low Aβ groups in the entorhinal ROI (suprathreshold, 0.025 [95% CI, 0.013-0.037] standardized uptake value ratio [SUVR] units; subthreshold, 0.026 [95% CI, 0.014-0.037] SUVR units; low Aβ, 0.034 [95% CI, 0.02-0.049] SUVR units), inferior temporal ROI (suprathreshold, 0.025 [95% CI, 0.014-0.035] SUVR units; subthreshold, 0.027 [95% CI, 0.017-0.037] SUVR units; low Aβ, 0.035 [95% CI, 0.022-0.047] SUVR units), and the AD meta-ROI (suprathreshold, 0.023 [95% CI, 0.013-0.032] SUVR units; subthreshold, 0.025 [95% CI, 0.016-0.034] SUVR units; low Aβ, 0.032 [95% CI, 0.021-0.043] SUVR units) (all P < .001). Flortaucipir accumulation rates in the subthreshold and suprathreshold Aβ groups in temporal regions were nonsignificantly elevated compared with the low Aβ group. In the ADNI cohort, the variance was larger than in the Mayo Clinic Study of Aging but point estimates for annualized flortaucipir accumulation in the inferior temporal ROI were very similar. An estimated 216 participants who were CU per group with PET Aβ of 68 CL or more would be needed to detect a 25% annualized reduction in flortaucipir accumulation rate in the AD meta-ROI with 80% power. Substantial flortaucipir accumulation in temporal regions is greatest in persons aged 65 to 85 years who were CU and had high initial Aβ PET levels, compared with those with lower Aβ levels. Recruiting persons who were CU and exhibiting Aβ of 68 CL or more on an index Aβ PET is a feasible strategy to recruit for clinical trials in which a change in tau PET signal is an outcome measure.

S2313 A Rare Presentation of an IL-12/23 Antagonist in Crohn’s Disease and Development of Sarcoidosis

INTRODUCTION: Anti-tumor necrosis factor (anti-TNF) therapy has been studied for use in inflammatory conditions such as IBD. There is a growing awareness of paradoxical reactions during treatment with this biologic agent. These can be defined as the development or exacerbation of a pathological condition which is triggered by the biologic agent being used. Commonly reported reactions include skin or joint manifestations, colitis or ileitis, or vasculitis. Paradoxically anti-TNF biologics have been reported to be useful to treat sarcoidosis and have been reported to cause sarcoidosis. Ustekinumab an IL-12/23 antagonist has been reported to cause sarcoidosis in 2 patients with psoriasis. We report the first case of a patient developing sarcoidosis during ustekinumab therapy for Crohn’s disease. CASE DESCRIPTION/METHODS: A 49 year-old female with history of breast carcinoma status-post mastectomy and adjuvant chemotherapy presented to clinic with abdominal pain and rectal bleeding. Prior colonoscopy on 6/26/17 only revealed pan-colonic diverticulosis. Colonoscopy on 10/12/18 revealed non-bleeding internal hemorrhoids, left-sided diverticulosis, sigmoid erythema/inflammation, and a normal terminal ileum. Sigmoid biopsies revealed chronic active colitis. She was started on Lialda with symptom resolution. The patient relapsed and was subsequently started on prednisone. Given the improvement with corticosteroids and suspicion of IBD, the patient was started on ustekinumab with a steroid taper and symptoms remained improved. Follow-up positron emission tomography scan for her breast cancer revealed uptake along the esophagus with development of mediastinal and bilateral hilar lymphadenopathy. Since there was concern for cancer, an EGD was performed, revealing only reflux esophagitis. Biopsies by pulmonology of her lymphadenopathy (EBUS) revealed noncaseating granulomatous sarcoidosis without evidence of malignancy. Ustekinumab was discontinued and the patient was restarted back on prednisone and Lialda with improvement. DISCUSSION: Side effects of ustekinumab, a monoclonal antibody to interleukin 12 and 23, can include cancers or serious infections. Our case describes a rare development of sarcoidosis in a Crohn’s Disease patient on ustekinumab therapy. The mechanism for this reaction remains unclear. The case does highlight the importance of knowing that all lymphadenopathy is not due to cancer even in patients with a cancer history and ustekinumab can cause sarcoidosis in patients with inflammatory bowel disease.

Correlation of Dynamic O-(2-[18F]Fluoroethyl)-L-Tyrosine Positron Emission Tomography, Conventional Magnetic Resonance Imaging, and Whole-Brain Histopathology in a Pretreated Glioblastoma: A Postmortem Study

Amino acid positron emission tomography (PET) using O-(2-[18F]fluoroethyl)-L-tyrosine (FET) provides important additional information on the extent of viable tumor tissue of glioblastoma compared with magnetic resonance imaging (MRI). Especially after radiochemotherapy, progression of contrast enhancement in MRI is equivocal and may represent either tumor progression or treatment-related changes. Here, the first case comparing postmortem whole-brain histology of a patient with pretreated glioblastoma with dynamic invivo FET PET and MRI is presented. A 61-year-old patient with glioblastoma initially underwent partial tumor resection and died 11 weeks after completion of chemoradiation with concurrent temozolomide. Three days before the patient died, a follow-up FET PET and MRI scan indicated tumor progression. Autopsy was performed 48 hours after death. After formalin fixation, a 7-cm bihemispherical segment of the brain containing the entire tumor mass was cut into 3500 consecutive 20μm coronal sections. Representative sections were stained with hematoxylin and eosin stain, cresyl violet, and glial fibrillary acidic protein immunohistochemistry. An experienced neuropathologist identified areas of dense and diffuse neoplastic infiltration, astrogliosis, and necrosis. Invivo FET PET, MRI datasets, and postmortem histology were co-registered and compared by 3 experienced physicians. Increased uptake of FET in the area of equivocal contrast enhancement on MRI correlated very well with dense infiltration by vital tumor cells and showed tracer kinetics typical for malignant gliomas. An area of predominantly reactive astrogliosis showed only moderate uptake of FET and tracer kinetics usually observed in benign lesions. This case report impressively documents the correct imaging of a progressive glioblastoma by FET PET.

A Unique Case of Rituximab-Induced Crohnʼs Disease: A Case Report and Review of Literature

Rituximab is a humanized monoclonal antibody against CD20 which is a mainstay of therapy for a wide variety of B cell malignancies. There are only two reported cases of Crohn's disease following treatment with Rituximab in the literature. We present a very unique case of a 58 year old female who was treated with Rituximab, Cyclophosphamide, Doxorubicin, Vincristine and Prednisolone (R-CHOP) regimen for initial diagnosis of follicular cell lymphoma of the tonsils. She was treated with prolonged maintenance Rituximab treatment for a recurrence of the lymphoma two years later and the treatment was continued for two and a half years. Three years later she was noted to have increased activity in the terminal ilium and mesenteric lymph nodes on a routine positron emission tomography (PET) scan. At that time, she was asymptomatic and refused any further workup or treatment. Another PET scan done two years later showed enlarged mesenteric lymph nodes with increased activity in the terminal ileum and the spleen. A colonoscopy performed at that time revealed inflammation with extensive ulceration in the terminal ileum. Biopsy demonstrated severely active chronic nonspecific ileitis with ulceration and a small granulomatous lesion. She was then re-treated again with 4 cycles of rituximab for a presumed recurrence. Two months after the treatment, she developed severe abdominal pain leading to an emergency room visit. A computerized tomography (CT) scan showed thickening in the distal descending colon as well as the entire sigmoid colon with surrounding fat stranding. She was treated with oral ciprofloxacin and metronidazole for 10 days with improvement in the symptoms. In a follow-up PET scan done a month later, the mesenteric adenopathy resolved but the activity in the terminal ileum was unchanged and there was new activity in the sigmoid colon. The patient refused further endoscopic examination, however the PET scan findings of worsening of the bowel inflammation and resolution of the adenopathy strongly suggests Rituximab induced Crohn's disease. This case portrays the importance of being alert to the possibility of Crohn's disease occurring as complication of Rituximab treatment. This case is unique as the Crohn's disease occurred almost three years after the initial Rituximab treatment. Management of Crohn's disease in patients with a history of lymphoma can be challenging due to the risk of lymphoma from Anti-TNF and immunomodulatory treatments.Figure: PET Scan showing increased uptake in the mesenteric lymph nodes and terminal ileum.Figure: Colonoscopy image of the terminal ileum.

Positron-emission tomography enhancement after vocal fold injection medialization.

The potential for the misinterpretation of positron-emission tomography (PET) scans in the context of a possible malignancy has been confirmed in a case report showing increased 18F-fluorodeoxyglucose (FDG) uptake after unilateral vocal fold augmentation medialization. We sought to expand these findings by investigating FDG uptake in a larger cohort of patients via a retrospective chart review. We examined the records of 15 adults-8 men and 7 women-who had undergone vocal fold augmentation for unilateral vocal fold paralysis and at least one subsequent PET scan. The differences in PET standard uptake value (SUV) between the injected and noninjected vocal folds were assessed via the Wilcoxon signed-rank test. A Spearman rank correlation coefficient was then used to estimate the relationship between differences in PET uptake and the length of time between the injection and the follow-up PET scan. The mean SUV of the injected vocal folds was 3.70, and the mean in the noninjected folds was 2.97. The difference did not achieve statistical significance (p = 0.34). In addition, the rank correlation coefficient with regard to the association between the difference in PET uptake and the duration between injection and PET was -0.24, suggesting an inverse relationship. However, the correlation coefficient did not differ significantly from zero (p = 0.34). We conclude that PET uptake after vocal fold augmentation medialization is variable and that it can increase substantially. This information should be considered in the context of the diagnostic accuracy of malignancy on PET.

Pancreatic neuroendocrine tumor masquerading as metastasis in a patient with esophageal cancer: Diagnosis by endoscopic ultrasound-guided fine-needle aspiration

AbstractThe role of endoscopic ultrasound (EUS) and guided biopsies has been well established for the locoregional staging of esophageal cancers. However, their role in posttreatment surveillance is unclear. Here, we describe a case of a pancreatic mass diagnosed on the follow-up positron emission tomography scan, concerning for a metastatic lesion. EUS-guided fine-needle aspiration (FNA) helped in establishing the diagnosis of neuroendocrine tumor, which tends to have a similar sonographic appearance. Therefore, it is imperative to evaluate a suspicious mass seen on computed tomography/positron emission tomography scan. EUS and EUS-guided FNA can serve as useful modalities to confirm the diagnosis by cytopathology.

PET Scans as a Predictive Marker of Survival in Advanced Colorectal Cancer

BackgroundThe clinical utility of fluorodeoxyglucose (FDG)-positron emission tomography (PET) scan in predicting the outcome of patients with metastatic colorectal cancer (mCRC) has not been well studied. We hypothesized that standardized uptake value (SUV) in FDG-PET scans after treatment predicts outcomes among patients with mCRC. Patients and MethodsWe retrospectively reviewed mCRC patients who had FDG-PET scans before their treatment and measured their SUV on follow-up imaging at the Karmanos Cancer Institute. Primary end points of time to progression (TTP) and overall survival (OS) were compared in 2 groups: follow-up (posttreatment) SUV of 0 versus > 0. ResultsThe study population consisted of 44 patients (median age of 58.1 years). Forty (91%) of the patients were treated first-line, 34 (77%) received an oxaliplatin-based regimen, and 7 (16%) received an irinotecan-based regimen. Thirty-four (77%) patients received concurrent bevacizumab. Median pretreatment SUV was 9.2 (range, 1.7-46.3), and median posttreatment SUV (in n = 41) was 4.0 (range, 0-14). The median percent change in SUV was −68.5% (range, −9.2% to −100%). The median time interval between scans was 2.6 months. There was no statistically significant difference noted between metabolic responders and nonresponders with regard to TTP and OS. However, patients with a posttreatment SUV of 0 had significantly longer OS than those with posttreatment SUV of > 0 (median, 42 vs. 25.2 months, respectively), and slightly longer TTP (median, 8.2 vs. 6.9 months, respectively). ConclusionSystemic therapy significantly decreased SUV on follow-up PET scans in advanced colorectal cancer patients. Absence of FDG uptake on follow-up PET scans was associated with markedly longer OS and slightly longer TTP.

Mediastinal mass in a healthy adolescent at The Children's Hospital at Westmead, Australia

### Ameneh Khatami and Emilie Huguon A previously well adolescent from the tropical South Pacific island of Futuna was transferred due to a 3-month to 4-month history of intermittent fevers,...

Resolution of Uptake on PET Scan after Removal of Large Colonic Polyps by Colonoscopy with EMR

Purpose: Background: Colonic polyps are infrequently identified as an incidental finding on F-18 fluorodeoxyglucose positron emission tomography (PET) scan. We present 2 patients with large colonic polyps detected during whole-body PET for evaluation of lung nodules. Cases: An 82 year old female had a PET scan revealing focal uptake which correlated with a thickened loop of bowel. The standardized uptake value (SUV) in this area was as high as 6.5g/mL. Her previous colonoscopy 5 years prior was normal. Colonoscopy 3 months after the scan revealed a 40 mm sessile, carpet-like polyp in the transverse colon. Pathology reported a tubular adenoma with high grade dysplasia without invasion. During three sessions over 9 months, endoscopic mucosal resection (EMR) was performed using saline and epinephrine (1:10,000 mixture) for a lift-technique with piecemeal resection and argon plasma coagulation to treat the remaining tissue. Follow-up PET scan after 12 months revealed no metabolic activity in the colon. Repeat colonoscopy 5 months after the third resection demonstrated no lesions at the previous site, and multiple biopsies showed normal colonic mucosa. A 79 year old male had a PET scan showing focal uptake seen in the distal transverse colon with an SUV of 12.6 g/mL. Colonoscopy one month later revealed a 30 mm sessile, carpet-like polyp. Pathology reported a tubulovillous adenoma. EMR was performed with a combination of saline, epinephrine (1:10,000 mixture) and methylene blue for a lift-technique using a hot snare. The lesion was removed using a piecemeal resection. Argon plasma coagulation was used on the remaining tissue. PET scan for lung cancer 4 months later reported no metabolic activity in the colon. The patient declined colonoscopy after the normal PET. Discussion: PET is being increasingly used for surveillance after cancer treatment. This modality can incidentally detect pre-malignant lesions in the colon as well, with a sensitivity and specificity of nearly 75% and 80%, respectively. Accuracy is improved with larger size and higher grade of dysplasia of the lesion. It is a poor colorectal cancer screening tool, however, due to its limitations such as high cost and radiation exposure. EMR during colonoscopy can remove large, sessile polyps, preventing progression to malignancy. It is a desirable modality in patients with multiple comorbidities who are poor surgical candidates. These cases demonstrate the ability of colonoscopy with EMR to eradicate lesions identified by focal colonic uptake on PET.

18F]Fluorodeoxyglucose Positron Emission Tomography for Detection of Bone Marrow Involvement in Children and Adolescents With Hodgkin's Lymphoma

Currently, a routine bone marrow biopsy (BMB) is performed to detect bone marrow (BM) involvement in pediatric Hodgkin's lymphoma (HL) stage greater than IIA. [(18)F]fluorodeoxyglucose positron emission tomography (FDG-PET) is increasingly used for the initial staging of HL. The value of using FDG-PET to detect BM involvement has not been sufficiently defined. We compared the results of BMBs and FDG-PET for the diagnosis of BM involvement in a large pediatric group with HL. The initial staging of 175 pediatric patients with newly diagnosed classical HL stage greater than IIA was determined by using BMB, FDG-PET, chest computed tomography (CT), and magnetic resonance imaging (MRI) or CT of the neck, abdomen, and pelvis. Staging images were prospectively evaluated by a central review board. Skeletal regions that were suggestive of BM involvement by either method were re-evaluated by using different imaging modalities. In suspicious cases, bone scintigraphy was performed. If follow-up FDG-PET scans were available, the remission of skeletal lesions during treatment was evaluated. BMB results were positive in seven of 175 patients and were identified by FDG-PET. FDG-PET scans showed BM involvement in 45 patients. In addition, the lesions of 32 of these 45 patients had a typical multifocal pattern. In 38 of 39 follow-up positron emission tomography scans, most of the skeletal lesions disappeared after chemotherapy. There was no patient with skeletal findings suggestive of BM involvement by MRI or CT with a negative FDG-PET. FDG-PET is a sensitive and specific method for the detection of BM involvement in pediatric HL. The sensitivity of a BMB appears compromised by the focal pattern of BM involvement. Thus, FDG-PET may safely be substituted for a BMB in routine staging procedures.

Basal Ganglia Activity in Pathological Gambling: A Fluorodeoxyglucose-Positron Emission Tomography Study

Background: Pathological gambling (PG) is a disorder classified as an impulse control disorder (DSM-IV) bridging impulsive, compulsive and addictive behaviors. The striatum and thalamus are supposed to be involved in the pathophysiological substrate of these behaviors. An increased relative glucose metabolic rate (rGMR) in patients with a diagnosis of PG had previously been reported in the medial and orbitofrontal cortex. We extended our studies to include functional alterations of the striatum and thalamus in a cohort of patients with PG before and after treatment with lithium. Methods: Twenty-one patients with PG who met lifetime comorbid bipolar spectrum diagnoses and a comparison group of 21 age- and sex-matched controls underwent a baseline positron emission tomography (PET) scan. Sixteen of these patients entered a randomized double-blind placebo-controlled parallel-group-design trial of lithium and underwent a follow-up PET scan at week 10. Anatomical MRI were obtained and the structures outlined on consecutive axial slices. These individual hand-drawn templates were used to identify structures on the PET scan of each patient, and the rGMR was measured. Results: The PG patients had a decrement of the rGMR in the ventral parts of the striatum and thalamus, and an increment of the rGMR in the dorsal parts as compared with the controls. Lithium treatment increased the ventral caudate rGMR to a trend level in the patients, but had no effect on the metabolism of either the putamen or the thalamus. Conclusion: Because of their extensive connectivity to the frontal cortex, striatal and thalamic functional alteration may contribute to faulty decision making processes in PG patients. By increasing the ventral rGMR of the caudate nucleus, lithium treatment may reduce cognitive dysfunction and symptoms in PG patients.

Meningeal Carcinomatosis From Cervical Cancer: A Case Report and Review of the Literature

Meningeal carcinomatosis (MC) from cervical cancer is rare. Diagnosis of this disease is often delayed due to variable presentation. We report an interesting case of MC from the uterine cervix and review general diagnostic and treatment considerations. The patient received chemotherapy and radiotherapy for stage IIB cervical cancer with resolution of symptoms for 3 years. Metastatic lesions were found in the right lung and paraaotic nodes on follow-up positron emission tomography scan, which completely resolved with subsequent chemotherapy. Unfortunately, the patient developed neurological symptoms consistent with MC, which was confirmed by cerebrospinal fluid cytology. Because of her poor cognition, available options were discussed with her family. She died peacefully in palliative care.

Positron emission tomography at the end of first-line therapy and during follow-up in patients with Hodgkin lymphoma: a retrospective study

BackgroundRoutine positron emission tomography (PET) in follow-up of Hodgkin lymphoma (HL) after treatment is still controversial. The aim of this retrospective study was to analyze the clinical impact of routine PET examination during the follow-up for relapse detection in PET-negative HL patients at the end of therapy. Patients and methodsPET scans were carried out in 113 HL patients at the end of therapy and during the follow-up either in regular intervals or in a suspected relapse. Median follow-up of the group was 34 months. ResultsOverall 327 PET scans were evaluated in 113 patients (median three PET scans per patient). At the end of therapy, 94 (83.2%) patients were PET negative and 19 (16.8%) PET positive. Regular follow-up PET scans in 67 of 94 PET-negative patients correctly identified tumor in 6 of 155 PET scans (3.9%). In 27 of 94 patients with clinically suspected relapse, 5 of 27 PET scans (18.5%) confirmed tumor. ConclusionsOur analysis showed that there is no need for regular follow-up with PET scans in PET-negative patients at the end of therapy: the ratio of true-positive PET scans during the follow-up is low (3.9%). Positive PET at the end of therapy and during follow-up should be evaluated with caution.