Abnormal FDG Accumulation Research Articles

Abnormal Cerebral FDG Accumulation in Acute Intracerebral and Subarachnoid Hemorrhages Due to Different Mechanisms.

Changes in cerebral glucose metabolism after acute intracranial hemorrhage have been rarely described. We present a patient with abnormal cerebral FDG accumulation in acute intracerebral and subarachnoid hemorrhages due to different mechanisms on FDG PET/CT. The patient received conservative management and died 2 months later. This case demonstrated the different mechanisms of cerebral FDG accumulation in different types of intracranial hemorrhage, which may be helpful for future research to optimize patient care.

Deep convolutional neural network for differentiating between sarcoidosis and lymphoma based on [18F]FDG maximum-intensity projection images.

To compare the [18F]FDG PET/CT findings of untreated sarcoidosis and malignant lymphoma (ML) and develop convolutional neural network (CNN) models to differentiate between these diseases using maximum intensity projection (MIP) [18F]FDG PET images. We retrospectively collected data on consecutive patients newly diagnosed with sarcoidosis and ML who underwent [18F]FDG PET/CT before treatment. Two nuclear radiologists reviewed the images. CNN models were created using MIP PET images and evaluated with k-fold cross-validation. The points of interest were visualized using gradient-weighted class activation mapping (Grad-CAM). A total of 56 patients with sarcoidosis and 62 patients with ML were included. Patients with sarcoidosis had more prominent FDG accumulation in the mediastinal lymph nodes and lung lesions, while those with ML had more prominent accumulation in the cervical lymph nodes (all p < 0.001). For the mediastinal lymph nodes, sarcoidosis patients had significant FDG accumulation in the level 2, 4, 7, and 10 lymph nodes (all p < 0.01). Otherwise, the accumulation in ML patients tended to be in the level 1 lymph nodes (p = 0.08). The CNN model using frontal and lateral MIP images achieved an average accuracy of 0.890 (95% CI: 0.804-0.977), a sensitivity of 0.898 (95% CI: 0.782-1.000), a specificity of 0.907 (95% CI: 0.799-1.000), and an area under the curve of 0.963 (95% CI: 0.899-1.000). Grad-CAM showed that the model focused on the sites of abnormal FDG accumulation. CNN models based on differences in FDG accumulation sites archive high performance in differentiating between sarcoidosis and ML. We developed a CNN model using MIP images of [18F]FDG PET/CT to distinguish between sarcoidosis and malignant lymphoma. It achieved high performance and could be useful in diagnosing diseases with involvement across organs and lymph nodes. • There are differences in FDG distribution when comparing whole-body [18F]FDG PET/CT findings in patients with sarcoidosis and malignant lymphoma before treatment. • Convolutional neural networks, a type of deep learning technique, trained with maximum-intensity projection PET images from two angles showed high performance. • A deep learning model that utilizes differences in FDG distribution may be helpful in differentiating between diseases with lesions that are characteristically widespread among organs and lymph nodes.

A case of colorectal large cell neuroendocrine carcinoma accompanied by disseminated peritoneal leiomyomatosis

BackgroundNeuroendocrine carcinomas (NECs) of the colon are among the rarest types of colorectal cancers. Among these, large cell type neuroendocrine carcinoma (LCNEC) is particularly rare. Colorectal NEC is an aggressive disease, and there are few reports of long-term survivors. Here, we report a case of LCNEC accompanied by disseminated peritoneal leiomyomatosis that was difficult to diagnose.Case presentationThe case involves a 62-year-old female found to be positive for fecal occult blood by medical examination. An endoscopy revealed a tumor in the ascending colon, and the biopsy revealed poorly differentiated cancer. Abnormal FDG accumulation with peritoneal thickening was visible on 18F-fluorodeoxyglucose positron-emission tomography (FDG-PET) and suspected to be peritoneal dissemination. Laparoscopic ileocecal resection was performed for the tumor of the ascending colon with abdominal wall invasion. At that time, numerous intra-abdominal nodules were observed, indicating peritoneal dissemination. The pathological diagnosis of the primary lesion was LCNEC, and the patient requested to undergo total peritoneal resection. After one course of chemotherapy with irinotecan plus cisplatin, she underwent total peritoneal resection, uterine annex resection, left inguinal lymph node resection, and intra-abdominal hyperthermic intraperitoneal chemotherapy with mitomycin C. Because a postoperative pathological examination revealed that the intra-abdominal nodules were leiomyomas, we diagnosed the patient with disseminated peritoneal leiomyomatosis. The left inguinal lymph node was diagnosed with a metastatic tumor. In summary, the final diagnosis was LCNEC in the ascending colon with inguinal lymph node metastasis. Postoperative chemotherapy has been administered to date. She is currently 18 months post-primary surgery and 15 months post-peritonectomy without apparent recurrence or metastatic findings.ConclusionWe experienced a case of Stage IVa colorectal LCNEC accompanied by disseminated peritoneal leiomyomatosis. Although the prognosis is generally poor, multidisciplinary treatment for advanced colorectal LCNEC may result in a favorable outcome for some patients. If peritoneal dissemination is suspected during operation, sampling of the nodule to confirm the pathological diagnosis is advisable.

Differences of articular and extra-articular involvement in polymyalgia rheumatica: A comparison by whole-body FDG-PET/CT

Objectives: To clarify differences in incidences of articular and extra-articular involvement in patients with polymyalgia rheumatica (PMR) using FDG-PET/CT.Methods: Twenty PMR patients were enrolled in this retrospective study. We compared frequency, degree, and patterns (diffuse or non-diffuse) of abnormal FDG accumulation in the proximal and distal articular structures (PAS, DAS), and extra-articular synovial structures (ESS). Regional analyses were performed for the large joints (shoulder, hip, and knee).Results: The incidences of positive FDG accumulation were significantly higher in the PAS (96.7%) and ESS (91.4%) than in the DAS (31.8%, p < .0001), although, the incidence in the knees (96.2%) was exceptionally high. PAS (2.79 ± 0.61) and ESS (2.52 ± 0.85) had significantly higher visual scores than DAS (0.89 ± 1.33, p < .0001). Shoulder, hip, and knee joints each had a different accumulation pattern. Strong FDG accumulation was frequently observed in the medial-to-subscapular part of the shoulder joints, the lateral part of the hip joints, and the medial part of the knee joints.Conclusion: ESS were found to be the main affected areas in PMR patients as well as PAS. DAS involvement occurred with low frequency except in the knee joints. Each large joint showed a different accumulation pattern and its own characteristically strongly affected areas.

Usefulness of Topically Applied Sensors to Assess the Quality of 18F-FDG Injections and Validation Against Dynamic Positron Emission Tomography (PET) Images.

Background: Infiltrations of 18F-fluorodeoxyglucose (FDG) injections affect positron emission tomography/computed tomography (PET/CT) image quality and quantification. A device using scintillation sensors (Lucerno Dynamics, Cary, NC) provides dynamic measurements acquired during FDG uptake to identify and characterize radioactivity near the injection site prior to patient imaging. Our aim was to compare sensor measurements against dynamic PET image acquisition, our proposed reference in assessing injection quality during the uptake period.Methods: Subjects undergoing routine FDG PET/CT imaging were eligible for this Institutional Review Board approved prospective study. After providing informed consent, subjects had sensors topically placed on their arms. FDG was injected into subjects' veins directly on the PET imaging table. Dynamic images of the injection site were acquired during 45 min of the uptake period. These dynamic image acquisitions and subjects' routine standard static images were evaluated by nuclear medicine physicians for abnormal FDG accumulation near the injection site. Sensor measurements were interpreted independently by Lucerno staff. Dynamic image acquisition interpretation results were compared to the sensor measurement interpretations and to static image interpretations.Results: Twenty-four subjects were consented and enrolled. Data from 21 subjects were gathered. During dynamic image acquisition review, physicians interpreted 4 subjects with no FDG accumulation at the injection site, whereas 17 showed evidence of accumulation. In 10 of the 17 cases that showed FDG accumulation, the FDG presence at the injection site resolved completely during uptake corresponding to venous stasis, the temporary sequestration of blood from circulation. Static image interpretation agreed with dynamic images interpretation in 11/21 (52%) subjects. Sensor measurement interpretations agreed with the dynamic images interpretations in 18/21 (86%) subjects.Conclusions: Sensor measurements can be an effective way to identify and characterize infiltrations and venous stasis. Comparable to an infiltration, venous stasis may produce spurious and clinically meaningful measurement bias and possibly even scan misinterpretation. Since the quality and quantification of PET/CT studies are of clinical importance, sensor measurements acquired during the FDG uptake may prove to be a useful quality control measure to reduce infiltration rates and potentially improve patient care.Registration: Clinicaltrials.gov, Identifier: NCT03041090

Differentiation between Polymyalgia Rheumatica (PMR) and Elderly-Onset Rheumatoid Arthritis Using 18F-Fluorodeoxyglucose Positron Emission Tomography/Computed Tomography: Is Enthesitis a New Pathological Lesion in PMR?

BackgroundIt is difficult to differentiate polymyalgia rheumatica (PMR) from elderly-onset rheumatoid arthritis (EORA) in clinical practice. We compared FDG-PET/CT findings between patients with PMR and those with EORA and extracted factors useful for differentiating the two disorders.MethodsWe compared abnormal FDG accumulation sites and maximum standardized uptake value (SUVmax) between 15 patients with PMR and 7 with EORA in whom FDG-PET/CT was performed.ResultsThe proportion of patients in the PMR group with abnormal FDG accumulation at the following 9 sites on FDG-PET/CT was significantly higher than that in the EORA group: periarticular region of the scapulohumeral joint, enthesis of the pectineus muscle, vicinity of the enthesis of the rectus femoris muscle, lateral side of the greater trochanter, ischial tuberosity, hip joint, spinous process of the lower cervical vertebra, intervertebral joint of the lumbar vertebra, and spinous process of the lumbar vertebra. The PET/CT score was evaluated at 9 sites consisting of the abovementioned sites. The median score in the PMR group was 8, which was significantly higher than that of 0 in the EORA group (P = 0.0003). ROC curve analysis was performed with the PET/CT scores, and a score of 5 was shown to maximize the area under the ROC curve (sensitivity: 86.7%, specificity: 86.7%).ConclusionsFDG-PET/CT is useful for differentiating PMR from EORA. In patients with PMR, abnormal FDG accumulation was observed at the entheses, suggesting the presence of enthesitis in addition to bursitis and synovitis.

Squamous Cell Carcinoma of the Prostate With Strong FDG Uptake on PET/CT

Primary squamous cell carcinoma (SCC) of the prostate is a rare aggressive neoplasm with a poor prognosis. A 60-year-old man presented with urinary frequency and interrupted urination for 4 months. Serum prostate-specific antigen and SCC antigen were elevated. T2-weighted MR images showed a hyperintense lesion in the central area of the prostate. FDG PET/CT showed strong FDG uptake of the lesion with SUVmax of 15.5. Prostate biopsy revealed moderate differentiated SCC. This case indicates SCC of the prostate should be considered in the differential diagnosis of abnormal prostate FDG accumulation (especially with elevated SCC antigen level).

FDG PET/CT in Eosinophilic Esophagitis

A 37-year-old man presented with left upper abdominal pain for 13 months. Laboratory examinations showed elevated peripheral eosinophils. Chest CT showed thickened wall of the entire esophagus. FDG PET/CT was performed showing diffuse FDG uptake in the thickened esophageal wall. Esophageal endoscopy showed pale and edematous mucosa. Histologic examination of the esophageal biopsy specimens revealed marked eosinophil infiltration of the mucosa. The clinical and pathologic findings were consistent with eosinophilic esophagitis (EoE). This case indicates EoE should be included in the differential diagnosis of abnormal FDG accumulation in the esophageal wall along with malignant and nonmalignant conditions.

FDG PET/CT Findings of Common Bile Duct Tuberculosis

Common bile duct (CBD) tuberculosis is rare. A 39-year-old woman was referred because of a 5-month history of abdominal pain. Abdominal enhanced MRI and CT showed dilatation of the distal CBD with irregularly thickened wall. Enhanced CT revealed enlarged retroperitoneal lymph nodes. FDG PET/CT showed increased FDG uptake of the CBD lesion and several retroperitoneal lymph nodes with slight FDG uptake. CBD cholangiocarcinoma with retroperitoneal lymph node metastasis was suspected. CBD tuberculosis was confirmed by endoluminal biopsy. Tuberculosis should be considered in the differential diagnosis of abnormal biliary FDG accumulation, particularly in tuberculosis endemic areas.

Increased FDG Uptake of Heterotopic Pancreatitis in the Stomach

Heterotopic pancreas is the presence of pancreatic tissue lying outside of its normal location and lacking anatomic or vascular connections with the pancreas. Heterotopic pancreas can undergo inflammatory changes similar to the normal pancreatic gland. We present 2 rare cases showing increased (18)F-FDG uptake in the heterotopic pancreatitis of the stomachs. To our knowledge, heterotopic pancreatitis with increased tracer accumulation on FDG PET/CT has not been reported before. Heterotopic pancreas should be included in the differential diagnosis of abnormal gastric FDG accumulation along with tumor and infectious processes.

Metastatic Brachial Plexopathy in a Case of Recurrent Breast Carcinoma Demonstrated on (18)F-FDG PET/CT.

This case highlights the importance of recognition of the pattern of metastatic brachialplexopathy in breast cancer patients undergoing 18F-fluorodeoxyglucose (18F-FDG) positron emission tomography/computed tomography (PET/CT) for evaluation of recurrent disease.This pattern can be appreciated on maximum intensity projection (MIP) and coronal 18F-FDG PET/CTimages as a linear extension of tracer activity from superomedial aspect(supra/infraclavicular) to lateral aspect of the axilla closely related to the subclavian/axillary vessels). A 35-year-old woman diagnosed with infiltrating ductal carcinoma of the right breast had undergone six cycles of neoadjuvant chemotherapy, followed by wide local incision and radiotherapy. She had local recurrence, for which she was operated upon and given chemotherapy. She presented to her oncologist with pain and swelling in the right breast, nodules in the right axilla and restriction of movement of the right upper limb. The patient was referred for 18F-FDG PET/CT to evaluate the extent of recurrent/metastatic disease. Whole-body PET/CT was acquired 1 h following the intravenous injection of 296 MBq of 18F-FDG on a Biograph mCT scanner (Siemens). Evaluation of the MIP image revealed abnormal FDG accumulation at multiple sites in the thorax, along with a linear pattern of FDG uptake in the right lateral aspect of the upper chest (Fig. 1a, arrow). The coronal fused PET/CT image revealed a linear pattern of FDG uptake corresponding to an ill-defined mass extending from just behind the right clavicle into the right axilla (arrow). In addition, abnormal FDG accumulation was seen in a soft tissue density mass in the upper outer quadrant of the right breast, skin of the right breast laterally, both pectoral muscles (discrete foci) and in a few subpectoral nodes. Soft tissue nodular opacities in both lungs showed FDG accumulation suggestive of pulmonary metastasis (Fig. 1b, thick arrow). The patient was referred for magnetic resonance imaging (MRI) to demonstrate the brachial plexus involvement. Coronal diffusion-weighted whole-body imaging with background body signal suppression (DWIBS) revealed a mass in the right axilla, with a b value of 1,000, infiltrating the cord and branches of the right brachial plexus visualised as linear hyperintensities (Fig. 1c, arrow). Fig. 1 Whole-body 18F-FDG PET/CT. a MIP image. b Coronal fused PET/CT image. c DWIBS image Brachial plexopathy in breast cancer patients can be metastatic (because major lymph drainage routes for the breast course through the axilla) or radiation induced, the former being the commoner of the two [1, 2]. Differentiation between the two pathologies is important for appropriate treatment planning. 18F-FDG PET/CT is a useful tool in the evaluation of patients with recurrent or metastatic breast cancer. Recognition of the pattern of brachial plexus involvement is thus essential for accurate interpretation of the 18F-FDG PET/CT study. To date, two case reports and one small case series [3–5] have demonstrated the feasibility of PET for confirming metastatic brachial plexopathy when MRI was suspicious of the same or when the patient was symptomatic for the same. This case highlights the possibility of metastatic brachial plexopathy even when the patient may not be overtly symptomatic for the same. The typical pattern as seen on MIP and coronal images is linear, extending from the superomedial aspect (supra/infraclavicular) to the lateral aspect of axilla closely related to the subclavian/axillary vessels). The commonest finding on computed tomography (CT) is that of an axillary mass, but may range from no remarkable abnormality to minimal thickening [2, 6]. Moreover, CT would not be able to differentiate metastatic from radiation plexopathy [2]. MRI is the first-line imaging modality for evaluating brachial plexopathy [7] and can delineate both normal and abnormal anatomy of the brachial plexus, with the ability to differentiate nerves from the surrounding vessels and soft tissue with greater detail than CT [7–10]. In this case, DWIBS was used to demonstrate the presence of a right axillary mass (discrete mass in relation to the plexus), which is the commonest finding on MRI in patients with metastatic plexopathy

THU0408 Deep inspiratory breath hold PET/CT is useful for monitoring of activity in rheumatic disease associated lung interstitial pneumonitis

ObjectivesThis study examined contributions of deep inspiratory breath hold (DIBH) -FDG-PET/CT to clinical assessment of ILD in collagen diseases.MethodsWe assessed ILD in 45 patients with collagen diseases including 6 RA,...

False Positive 18F-FDG Uptake in Mediastinal Lymph Nodes Detected with Positron Emission Tomography in Breast Cancer: A Case Report

Breast cancer is the most frequently diagnosed cancer among females. It is accepted that lymph node involvement with metastatic tumor and the presence of distant metastasis are the most important prognostic factors. Accurate staging is important in determining prognosis and appropriate treatment. Positron emission tomography with computed tomography detects malignancies using 2-[18F]-fluoro-2-deoxy-d-glucose (18F-FDG PET CT) with high accuracy and they contribute to decisions regarding diagnosis, staging, recurrence, and treatment response. Here, we report a case of false positive metastatic mediastinal lymph nodes that were diagnosed by 18F-FDG PET CT in a 40-year-old breast cancer patient who had undergone preoperative evaluation. Right paratracheal, prevascular, aorticopulmonary, precarinal, subcarinal, hilar, and subhilar multiple conglomerated mediastinal lymph nodes were revealed in addition to left breast mass and axillary lymph nodes. Mediastinoscopy was performed with biopsy and pathology was reported as granulomatous lymphadenitis. In conclusion, any abnormal FDG accumulation in unusual lymph nodes must be evaluated carefully and confirmed histopathologically.

F-18 FDG uptake in borderline intraductal papillary neoplasms of the bile duct

Intraductal papillary neoplasm of the bile duct (IPN-B) has been recently proposed as the biliary counterpart of intraductal papillary mucinous neoplasm of the pancreas. Histologically, IPN-B can be classified into adenoma, borderline, carcinoma in situ, and invasive carcinoma. Two patients with suspected intraductal tumor underwent fluorine-18 fluorodeoxyglucose positron emission tomography/computed tomography. One patient showed an FDG-avid tumor in the right liver with SUV(max) of 9.4 in early images and 11.3 in delayed images. The patient underwent complete tumor resection. Adenoma with high-grade dysplasia was confirmed by pathology. The other patient showed an FDG-avid polypoid lesion at the distal common bile duct with SUV(max) of 5.4. The lesion was endoscopically resected. Histopathologic findings showed adenoma with low-grade dysplasia. These two cases highlight that IPN-B should be included in the differential diagnosis of abnormal biliary intraductal FDG accumulation along with carcinoma, and inflammatory and infectious processes.

Routine Bone Marrow Biopsy Adds Little Diagnostic Information in Patients with Newly Diagnosed Hodgkin Lymphoma Undergoing PET/CT Staging

Abstract 2627Accurate staging is essential for the optimal choice of first-line treatment in Hodgkin lymphoma (HL). Bone marrow biopsy (BMB) is still widely recommended as part of the routine staging workup. However, this procedure may not be necessary for patients staged with [18]F-fluorodeoxyglucose positron emission tomography/computed tomography (PET/CT). The aims of this study were; 1) to determine if bone marrow infiltration can be excluded based on staging PET/CT result, and 2) to investigate whether BMB still adds useful information in the PET/CT era.Patients with newly diagnosed HL undergoing pre-therapeutic staging at three Danish university centers were eligible for inclusion in this retrospective study, provided both PET/CT and BMB were performed at staging. Patients were identified in the Danish Lymphoma Registry (LYFO). BMB results were first obtained from LYFO and validated by a review of local pathology records. PET/CT records were retrieved and reviewed. The patterns of skeletal FDG uptake were categorized as follows: 1) uni-focal, 2) bi-focal, 3) multi-focal or 4) diffuse homogeneous FDG uptake. Clinical stage and risk assessment were performed with and without the account of BMB results, according to the Ann Arbor classification, the International Prognostic Score (IPS), and the German Hodgkin Study Group risk criteria for limited disease.A total of 392 HL patients (Aalborg = 59, Aarhus = 67, Rigshospitalet = 266) were included, of whom 372 patients had classical HL and 20 had nodular lymphocyte predominant HL. According to staging PET/CT, 203 patients had limited stage disease and 189 patients had advanced stage disease. The median age at diagnosis was 39 years (range 15–87) and the female:male ratio was 3/4. BMB was positive for HL in 24 patients (6%), all of whom had been independently assessed by PET/CT as stage III (n=5) or IV (n=19) disease. Thus, no patients with PET/CT stage I-II disease, irrespective of the presence of B-symptoms, had HL infiltration in the BMB (p<0.0001, Fisher’s exact test).Skeletal FDG accumulation was seen in 90 patients and characterized as uni-focal (n=15), bi-focal (n=8), multi-focal (n=45) or diffuse (n=22). Among the 68 patients with focal skeletal FDG accumulation, 20 patients had positive BMB as compared to none of the patients with diffuse FDG uptake. Sixty out of 68 patients with focal skeletal FDG uptake had PET/CT response assessment during therapy. All patients who responded to therapy showed resolution of the pathological skeletal FDG uptake. The presence of focal skeletal FDG accumulation identified HL infiltration in the BMB with a sensitivity and specificity of 83% and 87%, respectively. The positive and negative predictive values of focal skeletal FDG accumulation for HL infiltration in the BMB were 29% and 99%, respectively. With both positive BMB and focal skeletal FDG accumulation considered to reflect true bone/bone marrow involvement, the sensitivity for bone/bone marrow disease was 94% for PET/CT and 33% for BMB. In terms of prognostic information, BMB upstaged 1% of the patients (n=5) from stage III to stage IV, with a one-point change of the IPS as an additional consequence. However, none of the 392 patients were allocated to another risk group or treatment group on the basis of BMB results.At present there is no optimal gold standard for diagnosing bone/bone marrow disease in HL. Unilateral iliac crest BMB examines a very limited part of the total bone marrow volume, while PET/CT visualizes abnormal FDG accumulation throughout large parts of the skeletal system. Whether abnormal skeletal FDG uptake represents HL in all cases remains to be clarified. The most consistent finding of the present study was the absence of positive BMBs in PET/CT assessed stage I-II disease, where routine BMB seems to have no relevance. Furthermore, the omission of staging BMB would have had no impact on the treatment strategy in this cohort of 392 newly diagnosed HL patients. Disclosures:No relevant conflicts of interest to declare.

Angiographic-CT-FDG-Pathologic Correlations of the Incidentally Discovered Adrenal Mass

During abdominal ultrasonography of a 37-year-old man a 3.2 cm hypoechoic mass in the right hepatic lobe was found incidentally. This prompted an abdominal CT, an FDG PET/CT, and an angiography to evaluate the nature of the mass. Laboratory data showed positive anti-HBs/anti-HBe, and negative HCV antibody. The alfa-fetoprotein and liver function tests were within normal limits. Contrast-enhanced CT found an enhanced hepatic tumor and primary hepatocellular carcinoma was suspected. PET/CT revealed no abnormal FDG accumulation in the right hepatic mass. The digital subtraction angiographies of the right inferior phrenic artery and right renal artery revealed a hypervascular tumor in the right adrenal gland. Therefore, a diagnosis of a right adrenal tumor was made. Serum aldosterone, serum cortisol, and urine vanillylmandelic acid, and catecholamine were all within normal limits. Laparoscopic right adrenalectomy was performed and adrenal cortical adenoma was diagnosed on a histological study.

Application of 18F-fluorodeoxyglucose positron emission tomography to detection of proximal lesions of obstructive colorectal cancer

In cases of obstructive colorectal cancer (CRC), preoperative diagnosis of the proximal lesion is often difficult when the primary lesion impedes the passage of the endoscope. The aim of this study was to evaluate the usefulness of fluorine-18-fluorodeoxyglucose positron emission tomography (FDG-PET) in such cases. A total of 52 obstructive CRC patients who underwent preoperative FDG-PET and subsequent surgical resection were retrospectively reviewed. The correlation between characteristics of the proximal lesion and FDG-PET findings was analyzed statistically. There was a significant correlation between the proximal lesion size and the maximum standardized uptake value (P = 0.00016). Abnormal FDG accumulation in the proximal colon indicated the existence of proximal cancer or adenoma with a sensitivity of 50% and a specificity of 100%. There was a significant difference in the distribution of tumor size between the cases with proximal abnormal accumulation and those with no proximal accumulation (P = 0.00014). A proximal tumor of ≥8 mm can be demonstrated by an accumulation of FDG with a sensitivity of 94.1%. FDG-PET can estimate the existence of a proximal lesion and its size. Results may contribute to decisions regarding the type of surgery in cases of obstructive CRC.

Carcinoma of the Lung Misinterpreted as Pulmonary Sequestration on Contrast CT But Correctly Identified on FDG PET/CT

Abstract: The chest x-ray of a 68-year-old man with a history of cough with blood-tinged sputum showed an abnormality in the right lower lung. Contrast-enhanced CT favored pulmonary sequestration with a feeding artery from the right inferior phrenic artery and a drainage vein into the right pulmonary vein. He had shortness of breath and chest tightness, which prompted an FDG PET/CT study to evaluate the nature of the mass. The images revealed abnormal FDG accumulation in a right lower lung mass and a mediastinal lymph node. Therefore, a possible diagnosis of lung carcinoma with mediastinal lymph node metastasis was suggested. A right lower lobe lobectomy was performed. Histopathologically, squamous cell carcinoma with mediastinal lymph node metastases was diagnosed (stage IIIA by AJCC, T2N2).

Application of FDG-PET for detection of malignant lesions in patients with elevated blood tumor markers but without a history of malignancy

The aim of this study was to evaluate the clinical application of 18-fluorodeoxyglucose positron emission tomography (FDG-PET) imaging for the detection of malignant lesions. A total of 132 patients with increased levels of blood tumor markers but without a prior history of malignancy were examined. The results of FDG-PET and conventional work-up (CWU) including computed tomography (CT), ultrasonography, radionuclide bone scintigraphy and endoscopy were compared. The final diagnosis was based on pathological evidence, other medical imaging results and a follow-up of at least 6 months. There were 61 patients with malignant lesions and 71 without (benign lesions, n=35; healthy individuals, n=36). The average number of elevated tumor markers and the average increase in these tumor markers were greater in the malignant group than in the non-malignant group. FDG-PET imaging revealed that the maximum standardized uptake value (SUVmax) of the major lesion in patients with malignant (n=61) and benign (n=35) tumors was not significantly related to increased levels of tumor markers (r=0.10, p<0.05). In patients with malignant lesions and an SUVmax ≥3.0, the diagnostic sensitivity, specificity, accuracy, positive predictive value and negative predictive value of FDG-PET were 95.1, 83.1, 88.6, 82.9 and 95.2%, respectively. CWU identified 61 (100%) true-positive patients. No statistically significant differences in sensitivity were observed between the results of FDG-PET and CWU (p>0.05). In 36 healthy subjects without abnormal CWU findings, no abnormal FDG accumulation was revealed by FDG-PET imaging. In conclusion, FDG-PET imaging is a valuable tool for the detection of malignant lesions in patients with increased levels of blood tumor markers but without a history of malignancy. It is therefore reasonable to apply FDG-PET imaging in situations in which the results of CWU are inconclusive, or when patients wish to limit the number of examinations they must undergo.

Mucosa-associated lymphoid tissue lymphoma studied with FDG-PET: a comparison with CT and endoscopic findings

We investigated the accumulation of 2-deoxy-2-[(18)F] fluoro-D: -glucose positron emission tomography (FDG-PET) in patients with mucosa-associated lymphoid tissue (MALT) lymphoma patients as compared with computerized tomography (CT) and endoscopic imaging. FDG-PET was performed on 13 untreated patients with MALT lymphoma. CT scanning of the affected areas was performed in all the patients to compare with the FDG-PET images. In five patients with gastric MALT lymphoma, comparison was also made with the endoscopic findings. Of the 13 untreated MALT lymphoma patients, all 8 non-gastric MALT lymphoma patients exhibited abnormal accumulation of FDG. However, in the five gastric MALT lymphoma patients, no abnormal FDG accumulation was observed. Although lesions could be confirmed on CT images from the patients other than those with gastric MALT lymphoma, the mucosal lesions of gastric MALT lymphoma could be observed only by endoscopy. FDG-PET can be used to detect MALT lymphoma when it forms mass lesions, whereas it is difficult to detect non-massive MALT lymphoma of gastrointestinal origin.