Positron Emission Tomography In Detection Research Articles

Warranty period for low risk positron emission tomography for detection of cardiac allograft vasculopathy

Abstract Background Positron emission tomography/computed tomography (PET/CT) is increasingly being used as an alternative to invasive coronary angiography for the detection of cardiac allograft vasculopathy (CAV) in heart transplant patients. The appropriate screening interval for patients with low-risk testing is unknown. Purpose The purpose of the study was to determine the number of patients with an initial-low risk PET/CT who progressed to a high-risk result with annual screening and what patient characteristics were associated with this progression. Methods Patients with heart transplant with no history of CAV 2/3 by angiography, whose initial PET/CT scan was low-risk, and who had a repeat PET/CT as part of an annual screening program were included in the study. A low-risk PET/CT was PET CAV score 0/1, and a high-risk PET/CT was PET CAV score 2/3, as defined by a previously published and validated diagnostic algorithm. The primary outcome was the percentage of patients who progressed to a high-risk result. Results The median time between PET/CT scans was 382 days (IQ 365 – 443). Only 2/163 (1.2%) patients with initial PET/CAV 0 progressed to PET CAV 2/3 on their repeat study compared to 7/37 (19%) for those with PET CAV 1 (RR 9.16, 95CI 2.97 – 28.29). During the study period, there were 0 episodes of urgent revascularization and 1 elective revascularization. Conclusions The risk of developing PET CAV 2/3 in patients with an initial result of PET CAV 0 is low at one year and annual screening may be unnecessary. Conversely, in patients initially classified as PET CAV 1, the risk of progression to PET CAV 2/3 is high and more frequent screening may be indicated.

Role of Fluorine-18 Fluorodeoxyglucose Positron Emission Tomography in Detection of Portal Vein Tumor Thrombosis in Hepatocellular Carcinoma

A 56 year old gentleman with no known comorbidities presented with pain abdomen for 1 month. Triphasic CECT abdomen showed features of cirrhosis with surface irregularities, fissural widening and volume redistribution changes in the liver. Segment VII of liver showed an arterial enhancing lesion measuring 4.2 x 3.5cm showing washout in delayed phase. In view of BCLC A stage with Child Pugh B7, ablation was planned. Before proceeding with ablation, in view of very high alpha-fetoprotein (AFP) level of 9836 ng/mL, he was advised for metastatic evaluation with 18F-FDG PET-CT. The PET scan showed abnormal heterogeneous increased FDG uptake in segment VII of liver (SUV Max 4.7) with arterial enhancement and washout suggestive of metabolically active hepatocellular carcinoma. Also seen was an abnormal linear increased FDG uptake in right branch of portal vein (SUV Max 4.8) which was suggestive of portal vein invasion. In view of portal vein tumor thrombus, ablation procedure was deferred for the patient. Role of PET scan in HCC with vascular invasion is not yet defined. Poor specificity of FDG PET is the major hindrance in establishing PET scan as diagnostic tool for vascular invasion. In small segment invasion when CECT is not able to differentiate between tumour versus bland thrombus PET scan may be significant tool to differentiate between bland thrombus and tumour thrombus. Vascular invasion confirmation have treatment related and prognostic significance. There is a need for a prospective study evaluating the prognostic significance of PET scan based diagnosis of vascular invasion.

Prospective study to assess the role of FDG PET/CT in detecting systemic metastatic spread in rectal cancers with lateral pelvic lymph nodes

IntroductionThe utility of positron emission tomography (PET) in detecting additional M1 patients over conventional staging modalities is not known in rectal cancer patients with enlarged lateral pelvic nodes. MethodsProspective, single center, single-arm interventional study of consecutive rectal cancer patients that had baseline lateral pelvic nodes on MRI (>10 mm) between February 2017 to December 2018. Such patients underwent PET after confirming non-metastatic status on CT of thorax and abdomen. Primary outcome measure was additional M1 sites detected on PET. A 10% distant metastasis rate was expected with 80% confidence interval (CI) set at 5% as the lower limit. Results44 patients were included and the concordance between MRI and PET in detection of lateral nodes was 97.7% (43 patients). Additional sites of metastasis were detected in 5 patients (11.36%; 80% CI - 5.63%–20.6%), and there was a change in treatment plan in 7 (15.9%). The number needed to treat (NNT) for PET scans to detect additional metastatic sites and change treatment were 9 and 6 respectively. There was a change in treatment intent (curative to palliative) in 2 patients (4.5%, NNT – 22). ConclusionIn rectal cancer patients with LPLN, the use of FDG-PET-CT over conventional staging studies led to the detection of additional extra-pelvic metastasis in 11.4% and changed the treatment plan in 15.9%. This met the pre-defined threshold to endorse the use of PET-CT in patients that match the study characteristics.

18F-fluorodeoxyglucose positron emission tomography for the detection of inflammatory lesions of the arterial vessel walls in Wistar rats.

The present study aimed to evaluate the use of 18F-fluorodeoxyglucose (18F-FDG) positron emission tomography (PET) for detection of high-fat and high-salt diet-induced inflammatory lesions of the arterial vessel walls in Wistar rats. A total of 20 healthy, 8-week-old, male Wistar rats were randomly assigned to the high-fat diet group and the normal diet group. After 16 and 24 weeks of feeding, Wistar rats in the normal diet group and the high-fat diet group (five rats in each group) were injected with 18F-FDG through the tail vein at a dose of 1 mCi/kg after fasting for 12 h. After 1 h, the rats were anesthetized with 2% isoflurane, followed by micro-PET imaging with a 10-min image capture duration and immunohistochemical staining. The standardized uptake values (SUVs) of 18F-FDG were significantly higher in the iliac artery in the high-fat diet group compared with those in the normal diet group at 16 weeks (1.53±0.08 vs. 1.04±0.03; P<0.05) and at 24 weeks (1.96±0.17 vs. 1.12±0.07; P<0.05). The SUVs of 18F-FDG were also significantly greater in the abdominal aorta in the high-fat diet group compared with those in the normal diet group at 16 weeks (1.35±0.08 vs. 1.02±0.02; P<0.05) and at 24 weeks (1.54±0.09 vs. 1.04±0.02; P<0.05). In addition, the SUVs of 18F-FDG in the iliac artery and abdominal aorta were significantly higher at 24 weeks compared with those at 16 weeks in the high-fat diet group (P<0.05). As determined by immunohistochemistry, the percentage of CD68-positive cells in the total number of cells per unit area in each group was 3.20±1.80% in the 24-week normal diet group, 4.70±2.02% in the 16-week high-fat diet group and 6.94±2.02% in the 24-week high-fat diet group; the percentage of CD68-positive cells in the high-fat diet group at 24 weeks was significantly higher than that in the high-fat diet group at 16 weeks and in the normal diet group at 24 weeks (P<0.05). In conclusion, 18F-FDG PET is a noninvasive imaging tool that can continuously monitor inflammatory lesions of the arterial vessel walls in Wistar rats. Further improvement of the Wistar rat atherosclerosis model may provide data to support the early assessment of and intervention in atherosclerosis.

Rubidium-82 positron emission tomography for detection of acute doxorubicin-induced cardiac effects in lymphoma patients

BackgroundDoxorubicin is a cornerstone in lymphoma treatment, but is limited by dose-dependent cardiotoxicity. Rubidium-82 positron emission tomography (82Rb PET) assesses coronary microvascular function through absolute quantification of myocardial perfusion and myocardial perfusion reserve (MPR). Doxorubicin-induced microvascular injury represents a potential early marker of cardiotoxicity. Methods and resultsWe included 70 lymphoma patients scheduled for doxorubicin-based treatment. Cardiotoxicity was evaluated with 82Rb PET myocardial perfusion imaging during rest and adenosine stress before chemotherapy and shortly after the first doxorubicin exposure. Patients with a MPR decline > 20% were defined as having a low threshold for cardiotoxicity. In the 54 patients with complete data sets, MPR was significantly lower after the initial doxorubicin exposure (2.69 vs 2.51, P = .03). We registered a non-significant decline in stress perfusion (3.18 vs 3.02 ml/g/min, P = .08), but no change in resting myocardial perfusion. There were 13 patients with a low cardiotoxic threshold. These patients had a significantly higher age, but were otherwise similar to the remaining part of the study population. ConclusionDecreases in MPR after initial doxorubicin exposure in lymphoma patients may represent an early marker of doxorubicin-induced cardiotoxicity. The prognostic value of acute doxorubicin-induced changes in MPR remains to be investigated.

37Diagnostic accuracy of [11C]PIB positron emission tomography for detection of cardiac amyloidosis

37Diagnostic accuracy of [11C]PIB positron emission tomography for detection of cardiac amyloidosis

Application of positron emission tomography in detection of myocardial glucose metabolism in rabbit cardiac arrest models

To investigate the changes of myocardial glucose metabolism in rabbit cardiac arrest models and the effect of hydrogen intervention by 18F-fluroro-2-deoxyglucose (18F-FDG) positron emission tomography (PET) imaging. Methods: Fifteen male New Zealand white rabbits were randomly divided into a hydrogen group (n=6), a control group (n=6) and a sham group (n=3). Cardiac arrest (CA) was induced by intravenous injection of potassium chloride. Conventional cardiopulmonary resuscitation (CPR) was initiated after five-minutes CA. The hydrogen group and the control group were mechanically ventilated into mixed gas with 4% hydrogen+96% oxygen and pure oxygen, respectively, for 30 minutes after CPR. Rats in the sham group was performed the same surgical procedure and was injected adrenaline and potassium chloride but did not induce CA. The vital signs at basic state and 30 min after return of spontaneous circulation (ROSC) were recorded in each group. The parameters of CPR were recorded in two CA groups. Myocardial glucose metabolism was assessed by positron emission tomography (PET) at basic state, 2 h and 24 h after ROSC. The maximum standardized uptake value (SUVmax) of 18F-FDG was measured. Results: There were no significant differences in the basal body weight and vital signs among the three groups. There was no significant difference in the blood glucose level before PET examination. The 18F-FDG SUVmax in the sham group at three time points was not significantly changed. In the hydrogen group and the control group, the 18F-FDG SUVmax at 2 h after ROSC were significantly higher than the basic level (1.89±0.47 vs 3.47±1.24 and 1.90±0.36 vs 4.26±0.80, respectively). Compared with the control group, the 18F-FDG SUVmax in the hydrogen group was lower at the point at 2 h after ROSC. The 18F-FDG SUVmax in the 2 CA group were down to the basic level at 24 h after ROSC (hydrogen group 2.02±0.64, control group 2.07±0.61). Conclusion: Myocardial glucose metabolism in CA rabbits was increased significantly after ROSC, and hydrogen intervention can reduce the degree of glucose metabolism.

Fluorodeoxyglucose positron emission tomography for detection of tumor recurrence following radiofrequency ablation in retrospective cohort of stage I lung cancer

Purpose: The goal of this study was to define patterns for tumor recurrence on PET following RFA, compare time to imaging recurrence by PET versus CT, evaluate whether pre-treatment tumor uptake predicts recurrence and propose an optimal post-RFA surveillance strategy.Materials and methods: A retrospective cohort study was performed of biopsy confirmed primary stage I lung cancers treated with RFA. FDG PET and near contemporaneous diagnostic CT imaging pre-ablation, within 30 days post-ablation, and beyond 6 months were independently and retrospectively evaluated for features supportive of recurrence. Time to imaging recurrence by PET (TTR_PET) and by CT (TTR_CT) were determined and compared. FDG avidity of untreated tumors was compared between recurrent and non-recurrent groups.Results: Thirteen recurrences after 72 RFA treatments were confirmed by diagnostic CT. All recurrences were associated with focally intense and increasing FDG uptake beyond 6 months (sensitivity 100%; specificity 98.5%). Mean TTR_PET was 14 months compared to mean TTR_CT of 17 months (not statistically significant). Normalized SUVmax and total lesions glycolysis of lung cancers that recurred after RFA was 4.0 and 6.0, respectively compared to 2.8 and 5.0, respectively for cancers that did not recur (p = .068).Conclusion: A pattern of focally intense and increasing FDG PET uptake has high sensitivity and specificity for detecting recurrent lung cancer following RFA. Surveillance after RFA should include a contrast enhanced diagnostic CT at 1 month to diagnose procedural complications, PET at 6 months as a post-treatment metabolic baseline (with diagnostic CT if PET is abnormal) and alternating diagnostic CTs or PET every 6 months for 2 years.

Breast cancer detected only by positron emission tomography with extensive osteolytic bone metastases mimicked Multiple Myeloma: A case report

Introduction Occult primary malignancy usually manifested itself as metastases or secondary–paraneoplastic phenomena. Although occult breast cancer usually presented as axillary lymphadenopathy, it could also have other rare manifestations, such as extensive osteolytic lesions which is the typical manifestation of Multiple Myeloma (MM). The similarity in radiological findings made differential diagnosis extremely difficult, especially when primary breast lesion was undetectable by ordinary diagnostic tools. Here we present a rare occult breast cancer case detected only by positron emission tomography (PET) with extensive osteolytic bone metastases that mimicked MM. Case description A 48-year-old female patient presented with heart burn, dyspenia and lower back pain. Skeletal survey revealed extensive osteolytic lesions including skull, spine and pelvis (Figure 1A-C), which were highly suspicious for MM. However, there were no Ben-Jones protein in urine and blood sample with mild proliferative bone marrow and normal plasma cell phenotype. Hence, after ruling out MM, PET scan was arranged to screen potential malignancies. It revealed a high uptake lesion in left breast with SUV 2.7 (Figure 1D) and multiple metastases. Although the breast lesion had a high SUV on PET, it was undetectable by mammography and ultrasound. Conclusions Extensive osteolytic lesions could be the first symptom of occult breast cancer. PET could be a useful tool for occult malignancies to identify primary lesion. Due to the relative low sensitivity of PET in detection of primary breast lesion, clinicians should be aware of occult breast cancer when PET revealed no implications for primary sites. Tissue biopsy of metastatic diseases could be another option to confirm the diagnosis. Take-home message 1. Extensive osteolytic lesions could be the first symptom of occult breast cancer. 2. PET could be a useful tool to identify primary lesion of occult malignancies. 3. PET has a relative low sensitivity of primary breast lesion, negative result could not rule out occult breast cancer. 4. Tissue biopsy of metastatic diseases could be another option to confirm the diagnosis.

Erratum to: What is the Accuracy of Nuclear Imaging in the Assessment of Periprosthetic Knee Infection? A Meta-analysis.

Erratum to: Clin Orthop Relat Res DOI 10.1007/s11999-016-5218-0 In the published study, “What is the Accuracy of Nuclear Imaging in the Assessment of Periprosthetic Knee Infection? A Meta-analysis” several errors can be found throughout the manuscript. In Table 1, the column title, “Number of hip prostheses (total/infected)” should be: “Number of knee prostheses (total/infected).” In Table 2, the column title, “Hip prostheses (primary/revision)” should be: “Knee prostheses (primary/revision).” In the legend for Table 2, “H = hybrid hip prostheses” should be removed. In the Discussion section, Figure 5A-B is incorrect as published. The corrected Fig. 5A-B is shown in this erratum.Fig. 5A-B: The pooled (A) sensitivity and (B) specificity of leukocyte scintigraphy in the assessment of periprosthetic knee infection with 95% CIs are shownThe title of Table 14 is incorrect. The title should be: “Diagnostic accuracy of fluorodeoxyglucose-positron emission tomography for detection of periprosthetic knee infection.” The title of Table 15 is incorrect. The title should be: “Study characteristics of fluorodeoxyglucose positron emission tomography for detection of periprosthetic knee infection.” Additionally, Figure 8A-B is incorrect as published. The corrected Fig. 8A-B is shown in this erratum. The authors apologize for the errors.Fig. 8A-B: The pooled (A) sensitivity and (B) specificity of FDG-PET in the assessment of periprosthetic knee infection with 95% CIs are shown. FDG-PET = fluorodeoxyglucose-positron emission tomography.

Application of Positron Emission Tomography in the Detection of Myocardial Metabolism in Pig Ventricular Fibrillation and Asphyxiation Cardiac Arrest Models after Resuscitation

ObjectiveTo study the application of positron emission tomography (PET) in detection of myocardial metabolism in pig ventricular fibrillation and asphyxiation cardiac arrest models after resuscitation. MethodsThirty-two healthy miniature pigs were randomized into a ventricular fibrillation cardiac arrest (VFCA) group (n=16) and an asphyxiation cardiac arrest (ACA) group (n=16). Cardiac arrest (CA) was induced by programmed electric stimulation or endotracheal tube clamping followed by cardiopulmonary resuscitation (CPR) and defibrillation. At four hours and 24 h after spontaneous circulation was achieved, myocardial metabolism was assessed by PET. 18F-FDG myocardial uptake in PET was analyzed and the maximum standardized uptake value (SUVmax) was measured. ResultsSpontaneous circulation was 100% and 62.5% in VFCA group and ACA group, respectively. PET demonstrated that the myocardial metabolism injuries was more severe and widespread after ACA than after VFCA. The SUVmax was higher in VFCA group than in ACA group (P<0.01). In VFCA group, SUVmax at 24 h after spontaneous circulation increased to the level of baseline. ConclusionACA causes more severe cardiac metabolism injuries than VFCA. Myocardial dysfunction is associated with less successful resuscitation. Myocardial stunning does occur with VFCA but not with ACA.

Comparison of magnetic resonance spectroscopy and positron emission tomography in detection of tumor recurrence in posttreatment of glioma: A diagnostic meta-analysis.

It is important to distinguish between tumor recurrence and treatment effects in posttreatment patients with high-grade gliomas. Several imaging modalities have been reported in differentiating between tumor recurrence and treatment effects. However, there were no consistent conclusions between different studies. We performed a meta-analysis of 23 studies that compared the diagnostic values of fluorine-18-fluorodeoxyglucose ((18)F-FDG) and (11)C-methionine ((11)C-MET) PET (positron emission tomography) or PET/CT (computed tomography) and magnetic resonance spectroscopy (MRS) in predicting tumor recurrence of gliomas. The pooled estimated sensitivity, specificity, positive likelihood ratios, negative likelihood ratios and summary receiver operating characteristic curves of (18)F-FDG and (11)C-MET PET or PET/CT and MRS in detecting tumor recurrence were calculated. In conclusion, MRS is highly sensitive in the detection of tumor recurrence in glioma.(18)F-FDG PET or PET/CT is highly specific in recurrence diagnosis. (11)C-MET does not have noticeable advantage over (18)F-FDG. The current evidence shows no statistical difference between MRS and PET on the accuracy.

Interest of tumor to liver ratio 18F-FDG uptake in positron emission tomography for detection of neurofibrosarcoma in neurofibromatosis 1 patients.

10049 Background: Malignant peripheral nerve sheath tumors (MPNSTs) are difficult to detect in neurofibromatosis 1 (NF1) individuals. The 18F FDG positron emission tomoscintigraphy (FDG PET) is a useful tool. The Standard Uptake Value (SUV) is the gold standard but it is subject to individual variation among patients and medical centers. So we assessed the interest of FDG PET based on a specific tumor to liver uptake ratio (T/L) instead of SUV to find a reproducible and constant cut-off for detecting malignant tumors. Methods: From 2000 to 2010, we conduct a multi centric study: all patients with NF1 and presenting clinical signs of MPNST suspicion (increased tumor size, induration or pain) underwent a FDG PET. Preliminary study estimated a T/L ratio of 1.5 as cut-off for malignity. Based on semi-quantitative analysis of FDG PET images, patients were compared with this cut-off value. Results: 98 patients with 125 tumors were included. FDG PET evaluation identified 42/125 suspected lesions with T/L &gt; 1.5; among these 30 MPNST and 12 benign lesions were found. 83/125 tumors were classified as non-suspicious and 82 were actually benign according to histology or long term follow up. The 1.5 T/L cut off corresponds to 99 % Negative Predictive Value (NPV) and 71% Positive (PPV). The positive likelihood ratio (LR) was thus equal to 7, 69 and the Negative LR to 0, with 97% sensitivity and 87% specificity. When T/L ratio is &lt; 1.5, MPNST is eliminated with 99% NPV, thus avoiding useless surgery. When T/L ratio is above 1.5, there is a strong suspicion of malignancy. But there is a risk of false positivity, which requires discussion before any therapeutic decision. On the over hand we found no significant correlation between SUVmax and malignancy. Conclusions: This study confirms the FDG PET in the detection of NF1-associated MPNST. The tumor/liver ratio with a cut off 1.5 has a very sensitive and specific value to sort out malignant from benign tumors and thus provides adequate surgery. More this semi-quantitative analysis method is just as easy as SUV, more sensitive and more reproducible.

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.

Positron emission tomography in detection of metastatic leiomyosarcoma in a postoperative patient: a case report

In leiomyosarcoma (LMS) abnormal vaginal bleeding is the most common reported symptom in patients (56%), followed by pelvic mass (54%), and pain (22%). LMS is often hard to diagnosis on a uterine biopsy because it does not originate in the endometrium and may not invade into the cavity. Non-specific symptoms as well as difficulty in diagnosis being made by biopsy, means that many LMS tumors are often mistaken for fibroids preoperatively. To our knowledge this is the only reported case of FDG-PET being used in the postoperative evaluation of a patient with LMS and a suspicious lung mass. Our case shows there may be a place for PET scans in the post-op surveillance of LMS. This method would be ideally suited, considering the metastatic spread pattern of LMS.

(18)F-FDG PET Demonstration of Cancer Recurrence Presenting as Dermatomyositis in a Rare Case of Primary Pleural Lymphoma.

Dermatomyositis (DM) or polymyositis (PM) are possibly considered to have an association with malignancies. We describe a case of dermatomyositis in which (18)F-fluorodeoxy glucose (FDG)positron emission tomography (PET) was able to detect cancer recurrence earlier than any other modality in a patient with a history of primary pleural lymphoma, a very rare condition of malignancy. Further, a typical finding of dermatomyositis is diffuse hypermetabolism in the bilateral proximal shoulder and pelvic girdle areas was shown on (18)F-FDG PET, which can implicate the inflammatory process in the skeletal muscle in dermatomyosistis. This case well illustrates the characteristic (18)F-FDG findings of dermatomyositis as well as a capability of (18)F-FDG PET in detection of recurrence of lymphoma, even in a rare condition.

Relative value of magnetic resonance spectroscopy, magnetic resonance perfusion, and 2-( 18F) fluoro-2-deoxy-D-glucose positron emission tomography for detection of recurrence or grade increase in gliomas

In a consecutive series of 26 previously operated patients diagnosed with cerebral glioma, magnetic resonance spectroscopy (MRS), 2-( 18F) fluoro-2-deoxy-D-glucose positron emission tomography (FDG-PET), and perfusion MRI (MRP), were performed at follow-up to distinguish recurrence from radiation necrosis, and to identify tumour upgrading. Discrepancy between techniques was observed in 9 cases. The positive predictive value (PPV) and the negative predictive value (NPV) of each technique to detect the presence of high grade glioma was: MRI, PPV = 50%; MRS, PPV = 91.6%, NPV = 100%; FDG-PET, PPV = 75%, NPV = 61.1%; MRP, PPV = 100%, NPV = 100%. In the selected group of nine cases studied to differentiate viable tumour from radiation necrosis, MRS and MRP reached a PPV and a NPV of 100%, whereas for FDG-PET, PPV and NPV were 66.6% and 60%, respectively. To distinguish between viable high-grade glioma and radiation necrosis, gadolinium-enhanced MRI gives a high false-positive rate, while MRS and MRP are superior to FDG-PET in discriminating tumour recurrence, grade increase and radiation necrosis.

2100 The role of 18F-FDG PET in detection of biliary tract cancer recurrence during surveillance: A single center observational study

To determine the accuracy of 2-[18F]-fluoro-2-deoxy-d-glucose (FDG) positron-emission tomography (PET) in the detection of advanced colorectal adenomas.In this retrospective study, patient consent was waived by the institutional review board. Combined FDG whole-body PET and computed tomography (CT) images (2000–2009) were re-read and compared with reports of complete colonoscopy performed up to 1 year after the PET examination. One or more areas of focal colonic uptake greater than the background indicated a positive PET result, irrespective of standardized uptake value (SUV). Lesion and patient-level measures of PET accuracy with their 95% confidence intervals (CI) were calculated.One hundred and eighty patients undergoing colonoscopy with or without biopsy underwent PET within 1 year prior to colonoscopy. There were 92 women and 88 men (mean age 63.3 years). Indications for PET were extent of disease and treatment response in all cases. Patients had non-colorectal cancer (n = 160) or colon cancer (n = 20). One hundred and fourteen FDG-avid lesions were present. In 33, there was no colonoscopic correlate. Two hundred and fifty-eight biopsies revealed tubular adenomas (n = 91, one with intra-mucosal cancer), tubulovillous adenomas (n = 28), adenocarcinoma (n = 37), inflammation (n = 22), hyperplastic polyps (n = 54), serrated adenoma (n = 5), metastatic disease (n = 5), normal/benign mucosa or submucosal benign tumors (n = 13) or miscellaneous (n = 3). Per-lesion performance of PET showed a sensitivity of 38% (95% CI: 31–46; 64/167) for all adenomas and carcinomas and 58% (95% CI: 49–67; 57/98) for lesions ≥10 mm. At the patient level, for all adenomas and carcinomas the sensitivity was 54% (95% CI: 44–63; 61/113), specificity 100% (pre-defined), positive predictive value (PPV) 100% (pre-defined), and negative predictive value (NPV) 56% (95% CI: 47–65; 67/119). For patients with advanced adenoma, PET sensitivity was 49% (95% CI: 35–63; 26/53) specificity, 100%, PPV 100% and NPV 82% (95% CI: 76–88; 127/154). Five of 37 adenocarcinomas were not detected, one of which was mucinous at histology.FDG PET detected most cancers, but only identified one-half of patients harbouring advanced adenomas. Based on the data, PET cannot be relied upon to accurately identify patients with advanced adenoma.

Reporting Standards for Percutaneous Thermal Ablation of Renal Cell Carcinoma

WITH the increasing incidence of renal cell carcinoma (RCC) in the United States and the increasing proportion of patients with tumors detected at an early stage (1–5), nephron-sparing approaches are becoming more popular. These alternatives to radical nephrectomy include partial nephrectomy, wedge resection, and, more recently, in situ thermal ablation. Five-year survival rates after partial nephrectomy are equivalent to those after radical nephrectomy (6–8), supporting the rationale of in situ tumor destruction to further reduce morbidity and invasiveness. In situ thermal destruction of RCC uses techniques that destroy tumor tissue through heating (eg, radiofrequency [RF] ablation, microwave ablation, laser interstitial therapy, high-intensity focused ultrasound [US]) or freezing (eg, cryotherapy). Each of these techniques relies on controlled energy delivery to minimize collateral damage to normal renal parenchyma and other surrounding structures. In the United States, RF ablation and cryoablation are currently the most widely used techniques for in situ RCC destruction. Thermal ablation of RCC may be performed percutaneously, laparoscopically, or through open surgery. Our current understanding of the role of percutaneous thermal ablation in the management of primary RCC is limited by a paucity of prospective studies (9,10). Given the relative newness of this technology, most series to date report short-term or midterm outcomes, with no reports extending to 5 years of survival outcomes. No randomized trials have been performed to date comparing thermal ablation against a gold standard (ie, partial nephrectomy) or against other thermal ablation techniques. The optimal size range of RCC amenable to thermal ablation has not been clearly defined and is closely related to anatomic factors that influence the ability to deposit sufficient thermal dose to coagulate tissue, including proximity to major vessels and the urinary collecting system, which can act as a heat sink. The kidney has approximately four times the blood flow of the liver, so convective heat loss during thermal ablation is potentially significant (11). The role of percutaneous thermal ablation compared with laparoscopic or open thermal ablation also remains a topic of controversy. The combination of thermal ablation with other imageguided therapies (eg, transcatheter embolization) and adjuvant therapies such as chemotherapy and antiangiogenic agents for larger RCCs in patients who are poor operative candidates is another potential use of this technique. Although most recent reports of percutaneous RCC ablation have involved RF ablation, other ablation technologies are now available with percutaneous applicators (eg, cryoablation, microwave, laser interstitial therapy), and reporting standards should be uniform for all forms of energy-based ablation. This document provides recommended reporting standards for physicians performing percutaneous thermal ablation of primary RCC and will serve as a template in the design of clinical trials to further evaluate this technology. From the Section of Vascular and Interventional Radiology, Department of Radiology (T.W.I.C.), New York University School of Medicine, New York, New York; Department of Radiology (S.F.M.), University of Western Ontario, Peterborough Regional Health Center, Peterborough, Ontario, Canada; Department of Radiology, Gastrointestinal/Genitourinary Division (D.A.G.), Massachusetts General Hospital; Department of Radiology (S.N.G.), Beth Israel Deaconess Medical Center, Boston; Department of Radiology (C.J.G.), Lahey Clinic Medical Center, Burlington; Department of Radiology (D.A.P.), University of Massachusetts Memorial Health Care, Worcester, Massachusetts; Department of Radiology (T.B.K.), University of California San Diego Medical Center, San Diego, California; Department of Radiology (D.S.), The Reading Hospital and Medical Center, Reading, Pennsylvania; and Department of Radiology (J.F.C.), University of Colorado Health Sciences Center, Denver, Colorado. Received June 19, 2006; revision requested June 19; final revision received June 29; and accepted July 3. Address correspondence to T.W.I.C., c/o Tricia McClenny, Society of Interventional Radiology, 3975 Fair Ridge Dr, Suite 400 North, Fairfax, VA 22033; E-mail: mcclenny@sirweb.org

Carbon 11–labeled methionine positron emission tomography for detection of residual viable tumor cells after adjuvant therapy in nongerminomatous malignant germ cell tumors in 2 cases including an autopsy case

Background The treatment of intracranial NGMGCTs is generally based on chemotherapy and radiotherapy. To avoid the potential of tumor recurrence, we normally have the residual mass lesion removed after adjuvant therapy. However, since 1988 we have treated 15 patients with NGMGCT and pathologically evaluated 12 such patients after adjuvant therapy by a new method we have developed and found viable tumor cells in 4 (33%) of 12 patients. Based on our experience, therefore, we feel we have been able to develop a reliable diagnostic tool for confirming the presence or absence of viable tumor cells in residual mass after adjuvant therapy for patients with NGMGCT. Case Description We describe here 2 patients with NGMGCTs who underwent MET-PET. Patient 1 was an 11-year-old boy with immature teratoma. On gadolinium (Gd)-enhanced magnetic resonance imaging (MRI), a high-intensity area was found in his right cerebellar hemisphere and a high uptake in MET-PET was confirmed in the same region. We judged it as the recurrence of the tumor. Finally, he died and was autopsied. Patient 2 was a 16-year-old girl with an NGMGCT who received combined chemo- and radiotherapy that led to a reduction in the volume of the tumor. Her serum β-HCG and HCG levels also returned to the reference range. However, the mass did not disappear and another MRI scan disclosed a residual Gd-enhanced lesion. To assess whether there were residual viable tumor cells, MET-PET was performed, and it demonstrated no hyper-uptake region in the residual mass. We, therefore, did not surgically remove the mass and kept the patient under observation. There has not been any tumor recurrence in this patient for more than 2 years. Conclusion In these 2 cases, the increased MET uptake was more specific of tumor tissue and more accurate than MR Gd enhancement. MET-PET may be a useful diagnostic tool for predicting viable tumor cells after adjuvant therapy in patients with NGMGCT, thus allowing further surgical intervention.