Noninvasive Assessment of Acute Graft-Versus-Host Disease of the Gastrointestinal Tract After Allogeneic Hemopoietic Stem Cell Transplantation Using 18F-FDG PET.

Acute graft-versus-host disease of the gastrointestinal tract (acute GIT-GVHD) often complicates allogeneic hemopoietic stem cell transplantation (AHSCT). 18F-FDG PET/CT is known to detect active inflammation and may be a useful noninvasive test for acute GIT-GVHD. The objective of this study was to evaluate the diagnostic utility of 18F-FDG PET/CT to noninvasively assess patients with clinically suspected acute GIT-GVHD. Fifty-one AHSCT patients with clinically suspected acute GIT-GVHD prospectively underwent 18F-FDG PET/CT scanning followed by upper and lower GIT endoscopy within 7 d. Endoscopic biopsies of 4 upper GIT and 4 colonic segments were obtained for histology to compare with corresponding quantitative segmental 18F-FDG PET/CT SUVmax Receiver-operating-characteristic curve (ROC) analysis was performed to determine predictive capacity of 18F-FDG PET/CT SUVmax for acute GIT-GVHD. A separate qualitative visual 18F-FDG PET/CT analysis was also performed for comparison. Results: Twenty-three of 51 (45.1%) patients had biopsy-confirmed acute GIT-GVHD, with 19 of 23 (82.6%) having upper GIT and 22 of 22 (100%) colonic involvement. One of 23 patients did not undergo a colonoscopy. GVHD involved the entire colon contiguously in 21 of 22 patients. For quantitative analysis, histology from 4 upper GIT and 4 colonic segments were compared with 18F-FDG PET/CT SUVmax Colonic segments positive for GVHD had a higher SUVmax (4.1 [95% CI, 3.6-4.5]) than did normal colonic segments (2.3 [1.9-2.7], P = 0.006). No difference was demonstrated in upper GIT segments. Quantitative 18F-FDG PET/CT yielded a 69% sensitivity, 57% specificity, 73% negative predictive value, and 59% positive predictive value for the detection of GVHD compared with 70%, 76%, 76%, and 68%, respectively, for qualitative analysis. Conclusion: 18F-FDG PET is a useful noninvasive diagnostic test for acute GIT-GVHD, which when present always involves the colon and usually in its entirety, suggesting colonic biopsy obtained by sigmoidoscopy is adequate for histologic confirmation when acute GIT-GVHD is suspected. Of note, 18F-FDG PET cannot distinguish acute GIT-GVHD from non-GVHD inflammatory changes in the colon.

18 F-FDG PET/CT features of immune-related adverse events and pitfalls following immunotherapy.

18 F-FDG PET/CT scanning is routinely performed to stage and evaluate the treatment response in many malignancies. Immunotherapy is a rapidly growing treatment option for many cancers, and both clinicians and imaging specialists need to be familiar with 18 F-FDG PET/CT imaging characteristics unique to patients on this type of treatment. In particular, many immune-related adverse events (irAEs) can be detected on 18 F-FDG PET/CT and early accurate identification is critical to reduce treatment related morbidity and incorrect interpretation of malignant disease status. This pictorial essay reviews frequently encountered irAEs in clinical practice and their appearances on 18 F-FDG PET/CT along with a brief discussion on pseudoprogression and hyperprogression.

Clinical utility of stimulated cholescintigraphy using a standardized Ensure-Plus fatty meal protocol in patients with suspected functional gallbladder disorder: a retrospective study of seven-years clinical experience.

BACKGROUND: The clinical utility of fatty meal stimulated cholescintigraphy particularly using a standardized formulation in patients with suspected functional gallbladder disorder has not been extensively studied. We present our seven-year clinical experience using an Ensure plus protocol. METHODS: A retrospective study was performed on patients undergoing stimulated cholescintigraphy using Ensure Plus for evaluation of suspected functional gallbladder disorder. A gallbladder ejection fraction (GBEF) of <33% was considered abnormal. RESULTS: Of the 173 patients evaluated, 57 (33%) had an abnormal GBEF, 112 (65%) had a normal GBEF and 4 (2%) had no gallbladder visualization. Of the 57 patients with an abnormal GBEF, symptom improvement occurred in 30/31 (97%) who underwent cholecystectomy and in 17/26 (65%) who were managed conservatively (p = 0.003). Of the 112 patients with a normal GBEF, symptom improvement occurred in 8/10 (80%) who underwent cholecystectomy and 74/102 (73%) who were managed conservatively (p = 1.000). In the subgroup of 102 patients with a normal GBEF managed conservatively, those without symptomatic improvement had lower GBEFs compared to those with symptomatic improvement (median GBEF 46% versus 57%, p = 0.019). CONCLUSION: Our retrospective results support a clinical role for stimulated cholescintigraphy using Ensure Plus in the evaluation of patients with suspected functional gallbladder disorder. While an abnormal GBEF predicts good surgical outcome, our results suggest that using an absolute GBEF cut off value of <33% may not apply to all patients and hence GBEF results should only be used as an adjunct in the surgical decision-making process.

Findings and Resolution of Melanoma Perineural Spread Along the Greater Auricular Nerve on FDG PET/CT and MRI.

ABSTRACT: We report an unusual case of a 59-year-old man with recurrent right ear melanoma resulting in perineural spread to the right greater auricular nerve. Direct perineural spread to the greater auricular nerve is not commonly reported in melanoma. Our case demonstrates perineural spread along the greater auricular nerve on 18F-FDG PET/CT and MRI. This finding was supported by intraneural invasion noted at the surgical margin of the wide local excision of the right helix melanoma. Resolution of FDG activity and improved MRI appearances of the right greater auricular nerve were seen after immunotherapy treatment.

Excellent suppression of physiological myocardial FDG activity in patients with cardiac sarcoidosis.

INTRODUCTION: Suppression of physiological myocardial FDG activity is vital in patients undergoing PET/CT for assessment of known or suspected cardiac sarcoidosis. This study aims to evaluate the efficacy of physiological myocardial FDG suppression following a protocol change to a 24-h high fat very low carbohydrate (HFVLC) diet and prolonged fast. METHODS: A retrospective review of patients undergoing FDG PET/CT for the evaluation of cardiac sarcoidosis was performed. Prior to June-2018, patients were prepared with a single very high-fat low carbohydrate meal followed by a 12-18 h fast (group 1). After June-2018, a protocol change was initiated with patients prepared with a HFVLC diet for 24-h followed by a 12-18 h fast (group 2). Focal myocardial activity was classified as positive, absent activity as negative and diffuse/focal on diffuse activity as indeterminate. RESULTS: A total of 94 FDG PET/CT scans were included with 46 scans in group 1 and 48 scans in group 2. Studies were classified as positive, negative or indeterminate in 25 (54%), 7 (15%) and 14 (30%) scans in group 1 and in 13 (27%), 33 (69%) and 2 (4%) scans in group 2, respectively. In scans classified as negative, myocardial FDG activity was less than mediastinal blood pool activity in 5/7 (71%) scans in group 1 and 33/33 (100%) scans in group 2. CONCLUSION: Excellent myocardial FDG suppression can be achieved using a 24-h HFVLC diet and prolonged fast, resulting in a very low indeterminate scan rate in patients with known or suspected cardiac sarcoidosis.

Clinical Outcomes of 177Lu-PSMA Radioligand Therapy in Earlier and Later Phases of Metastatic Castration-Resistant Prostate Cancer Grouped by Previous Taxane Chemotherapy.

177Lu-labeled prostate-specific membrane antigen (PSMA) radioligand therapy using PSMA-617 and PSMA-I&T ligands (177Lu-PRLT) is an emerging treatment in metastatic castration-resistant prostate cancer (mCRPC). This retrospective study evaluates clinical outcomes of 177Lu-PRLT in earlier and later phases of mCRPC grouped by previous taxane chemotherapy. Methods: A retrospective analysis was performed on 167 patients with mCRPC who underwent 177Lu-PRLT between March 2013 and December 2016. Patients were classified as either taxane chemotherapy pretreated (T-pretreated) or naïve (T-naïve) depending on whether they had received taxane-based chemotherapy prior to 177Lu-PRLT. Clinical outcome for T-pretreated and T-naïve patients was assessed by overall survival (OS), radiographic progression-free survival, and prostate-specific antigen (PSA) response rate. Univariate and multivariable analyses were performed for both T-pretreated and T-naïve patients to determine predictors of outcome. Toxicity was categorized by the Common Terminology Criteria for Adverse Events (version 4.03). Results: Of the 167 patients treated with 177Lu-PRLT, 83 were T-pretreated and 84 were T-naïve. At baseline, T-pretreated patients had overall poorer performance status, a higher prevalence of bone metastases, higher PSA levels, lower hemoglobin levels, higher alkaline phosphatase (ALP) levels and had received more additional therapies compared with T-naïve patients. Median OS was 10.7 mo for T-pretreated patients and 27.1 mo for T-naïve patients. Median radiographic progression-free survival was 6.0 mo for T-pretreated patients and 8.8 mo for T-naïve patients. PSA response assessment was evaluable in 132 patients and seen in 25 of 62 (40%) T-pretreated patients and 40 of 70 (57%) T-naïve patients. Significant determinates of inferior OS in multivariable analysis for T-pretreated patients were poorer performance status, lower cumulative administered activity, and lower baseline hemoglobin. Higher baseline alkaline phosphatase was the only significant determinate of inferior OS in multivariable analysis for T-naïve patients. Overall 177Lu-PRLT was safe, with minimal adverse effects evident during follow-up in both T-pretreated and T-naïve patients. Conclusion: 177Lu-PRLT is a promising therapy in mCRPC, with encouraging outcomes and minimal associated toxicity seen in both our T-naïve and heavily pretreated patient cohorts.

Normal brain metabolism on FDG PET/MRI during childhood and adolescence.

OBJECTIVE: The aim was to investigate normal patterns of brain metabolism determined by F-fluorodeoxyglucose positron emission tomography (FDG PET)/MRI during childhood and adolescence. PATIENTS AND METHODS: A retrospective analysis was carried out on all paediatric patients who underwent FDG PET/MRI at our institution between March 2016 and August 2017. Exclusion criteria were neurological disease, central nervous system metastases, previous chemotherapy/radiotherapy, general anaesthesia/sedation and medications suspected to affect cerebral metabolism. Standardized uptake value (SUV)mean and SUVmax were calculated for 12 brain grey matter regions. Subgroup analysis of childhood (≤10 years old) and adolescence (≥11 years old) was also carried out. RESULTS: From 492 PET/MRI scans, 28 patients (11 children, 17 adolescents) were deemed representative of normal brain metabolism. SUVmean and SUVmax increased with age in all regions. The highest rates of increasing SUVmean were in the thalamus, basal ganglia, frontal lobes, insula and occipital lobes. Higher SUVmean was found in the right frontal, right lateral temporal, right temporal pole, right cingulate/paracingulate, right thalamus, left occipital, left basal ganglia, left insula and left cerebellum compared with the contralateral side. This SUVmean asymmetry was present in both childhood and adolescence in the majority of regions. The highest rates of increasing SUVmax with age were in the occipital lobes, frontal lobes, thalamus and central region. There was no asymmetry in SUVmax in the majority of regions. CONCLUSION: This FDG PET/MRI study shows that normal brain metabolism measured by SUVmean and SUVmax increases with age in all regions, proceeding at different rates between distinct anatomical sites. Our results suggest that there is mild asymmetry in SUVmean, but mostly symmetric SUVmax during normal development.

Ga-68 octreotate PET/CT and Tc-99m heat-denatured red blood cell SPECT/CT imaging of an intrapancreatic accessory spleen.

Intrapancreatic accessory spleens are relatively uncommon and can be difficult to distinguish from neuroendocrine tumours on CT, MRI and somatostatin receptor scintigraphy. We present the case of a 26-year-old woman with an incidentally diagnosed pancreatic lesion confirmed to be an intrapancreatic accessory spleen on Tc-99m heat-denatured red blood cell single photon emission computed tomography/CT.

The prevalence of thyroglossal tract thyroid tissue on SPECT/CT following (131) I ablation therapy after total thyroidectomy for thyroid cancer.

OBJECTIVE: To determine the prevalence of thyroglossal tract thyroid tissue on SPECT/CT and to assess the contribution of this tissue to total neck radioactive iodine (RAI) activity in patients given (131) I ablation therapy after total thyroidectomy for thyroid cancer. PATIENTS AND METHODS: Eighty-three consecutive patients with thyroid cancer treated with total thyroidectomy underwent whole-body planar and SPECT/CT imaging of the neck following initial RAI ablation. On SPECT/CT, thyroglossal tract thyroid tissue was defined as RAI in the anterior neck, superior to the thyroid bed in close proximity to the midline without evidence of localization to lymph nodes. Quantification was performed using region of interest analysis on planar imaging following localization on SPECT/CT. SPECT/CT, and planar images were classified by two reviewers as positive, negative or equivocal with interobserver agreement quantified using a Kappa score. Disagreement was resolved using a third reviewer. RESULTS: Thyroglossal tract thyroid tissue was present in 39/83 (47%; 95%CI: 36-58%) patients on SPECT/CT. In these 39 patients, this tissue contributed to a significant amount of total neck activity (median = 50%; IQR 19-74%). Interobserver agreement for the presence of thyroglossal tract thyroid tissue was substantial on SPECT/CT (Kappa = 0.73) and fair on planar imaging (Kappa = 0.31). CONCLUSION: Thyroglossal tract thyroid tissue was present in one half of our study population and contributed to a significant amount of total neck RAI activity. Given the high prevalence of this tissue, our results suggest that total neck RAI activity on planar imaging may not be suitable to assess the completeness of thyroid bed surgery.

Comparison of positron emission tomography/CT and bremsstrahlung imaging following Y-90 radiation synovectomy.

INTRODUCTION: The aim of this study is to compare the results of positron emission tomography (PET)/CT with bremsstrahlung imaging following Y-90 radiation synovectomy. METHODS: All patients referred to our institution for Y-90 radiation synovectomy between July 2011 and February 2012 underwent both PET/CT and bremsstrahlung planar (± single photon emission computed tomography (SPECT) or SPECT/CT) imaging at 4 or 24 h following administration of Y-90 silicate colloid. PET image acquisition was performed for between 15 and 20 min. In patients who underwent SPECT, side-by-side comparison with PET was performed and image quality/resolution scored using a five-point scale. The distribution pattern of Y-90 on PET and bremsstrahlung imaging was compared with the intra- or extra-articular location of Y-90 activity on fused PET/CT. RESULTS: Thirteen joints (11 knees and two ankles) were imaged with both PET/CT and planar bremsstrahlung imaging with 12 joints also imaged with bremsstrahlung SPECT. Of the 12 joints imaged with SPECT, PET image quality/resolution was superior in 11 and inferior in one. PET demonstrated a concordant distribution pattern compared with bremsstrahlung imaging in all scans, with the pattern classified as diffuse in 12 and predominantly focal in one. In all 12 diffuse scans, PET/CT confirmed the Y-90 activity to be located intra-articularly. In the one predominantly focal scan, the fused PET/CT images localised the Y-90 activity to mostly lie in the extra-articular space of the knee. CONCLUSION: PET/CT can provide superior image quality compared with bremsstrahlung imaging and may enable reliable detection of extra-articular Y-90 activity when there are focal patterns on planar bremsstrahlung imaging.

18F-FDG PET/CT has a high impact on patient management and provides powerful prognostic stratification in the primary staging of esophageal cancer: a prospective study with mature survival data.

UNLABELLED: The aim of this study is to evaluate the incremental staging information, management impact, and prognostic stratification of PET/CT in the primary staging of esophageal cancer in a cohort of patients with mature survival data. METHODS: Between July 2002 and June 2005, 139 consecutive patients with newly diagnosed esophageal cancer underwent conventional staging investigations (CSI), followed by PET/CT. Disease stage was classified according to the American Joint Committee on Cancer staging system (6th edition) and grouped as stage I-IIA, stage IIB-III, and stage IV reflecting broad groupings that determine therapeutic choice. Validation of results was performed when PET/CT and CSI stage groups were discordant and in those patients where PET/CT changed management. Management impact was determined by comparing prospectively recorded pre-PET/CT management plans with post-PET/CT management plans. Survival after follow-up of at least 5 y in patients was analyzed using the Kaplan-Meier product limit method and the Cox proportional hazards regression model. RESULTS: PET/CT changed the stage group in 56 of 139 (40%) patients and changed management in 47 of 139 (34%) patients. In 22 patients, therapy was changed from curative to palliative and in 3 from palliative to curative; in 11, treatment modality was changed without a change in treatment intent, and in 11 the delivery of therapy or diagnostic procedure was changed. Of the 47 patients with management change, imaging results could be validated in 31 patients, and PET/CT correctly changed management in 26 (84%) of these. Of the remaining 5 patients, CSI stage was also incorrect in 4 and correct in 1. Median survival was 23 mo. PET/CT stages I-IIA, IIB-III, and IV had a 5-y survival of 40%, 38%, and 6%, respectively. Post-PET/CT stage group and treatment intent were both strongly associated with survival (P < 0.001). CONCLUSION: PET/CT provides incremental staging information compared with CSI, changes management in one third of patients, and has powerful prognostic stratification in the primary staging of esophageal cancer.

The morbidity and mortality conference: the delicate nature of learning from error.

The morbidity and mortality conference (M&MC) appears to have sprung from the efforts of physicians to improve practice through the examination of medical errors and bad outcomes. The modern M&MC has had limited examination (and almost none outside surgery and anesthesia), but may be straying from the precepts from which it evolved. Learning from one's errors is important, but confronting them is difficult and is particularly delicate when done in conference. If the effort is successful, it can serve as a model. If unsuccessful, it can instead convey the lesson that attempting to learn from error is at best unproductive and at worst unpleasant. Thus, the M&MC is a double-edged sword, and particular attention should be given to the way that it is conducted. The authors review the historical roots and current literature on the M&MC, discusses relevant literature on medical error, and offers a definition, guiding principles, and a set of guidelines for a modern internal medicine M&MC. The ideas are presented not as a blueprint, but rather to stimulate a debate on the merits of establishing a framework for a working model, in order to refocus on the tradition of self-analysis and critical thinking in a manner that is productive for all participants.