¹8F-FDG PET/CT in inflammation of unknown origin: a cost-effectiveness pilot-study.

PURPOSE: Patients with increased inflammatory parameters, nonspecific signs and symptoms without fever and without a diagnosis after a variety of diagnostic procedures are a diagnostic dilemma and are referred to as having inflammation of unknown origin (IUO). The objective of this pilot study was to compare the cost-effectiveness of a diagnostic work-up/strategy with and without (18)F-FDG PET/CT in patients with IUO using a published dataset as a reference. METHODS: IUO patients without (18)F-FDG PET/CT (group A, 46 patients) and IUO patients referred for (18)F-FDG PET/CT (group B, 46 patients) were selected. IUO was defined as the combination of nonspecific signs and symptoms and a prolonged erythrocyte sedimentation rate (ESR), defined as ≥age/2 in men and ≥(age + 10)/2 in women (ESR in millimetres per hour and age in years), and/or C-reactive protein (CRP) ≥15 mg/l. The costs of all tests and procedures and the number of hospitalization days in each patient to reach a diagnosis were calculated using current Dutch tariffs. RESULTS: In group A a diagnosis was reached in 14 of the 46 patients. The mean cost per patient of all the diagnostic procedures was 2,051, and including the cost of hospitalization was 12,614. In group B a diagnosis was reached in 32 of the 46 patients. The mean cost per patient of all the diagnostic procedures was 1,821, significantly lower than in group A (p < 0.0002), and including the cost of hospitalization was 5,298. CONCLUSION: In IUO (18)F-FDG PET/CT has the potential to become a cost-effective routine imaging technique indicating the direction for further diagnostic decisions thereby allowing unnecessary, invasive and expensive diagnostic investigations to be avoided and possibly the duration of hospitalization to be reduced. However, a prospective multicentre "bottom-up microcosting" cost-effectiveness study is warranted before these preliminary data can be extrapolated to clinical practice.

The role of 18F-FDG PET/CT in large-vessel vasculitis: appropriateness of current classification criteria?

Patients with clinical suspicion of large-vessel vasculitis (LVV) may present with nonspecific signs and symptoms and increased inflammatory parameters and may remain without diagnosis after routine diagnostic procedures. Both the nonspecificity of the radiopharmaceutical (18)F-FDG and the synergy of integrating functional and anatomical images with PET/CT offer substantial benefit in the diagnostic work-up of patients with clinical suspicion for LVV. A negative temporal artery biopsy, an ultrasonography without an arterial halo, or a MRI without aortic wall thickening or oedema do not exclude the presence of LVV and should therefore not exclude the use of (18)F-FDG PET/CT when LVV is clinically suspected. This overview further discusses the notion that there is substantial underdiagnosis of LVV. Late diagnosis of LVV may lead to surgery or angioplasty in occlusive forms and is often accompanied by serious aortic complications and a fatal outcome. In contrast to the American College of Rheumatology 1990 criteria for vasculitis, based on late LVV effects like arterial stenosis and/or occlusion, (18)F-FDG PET/CT sheds new light on the classification of giant cell arteritis (GCA) and Takayasu arteritis (TA). The combination of these observations makes the role of (18)F-FDG PET/CT in the assessment of patients suspected for having LVV promising.

Recurrent head and neck desmoplastic melanoma with perineural spread along the nervus mandibularis revealed by 18F-FDG PET/CT.

This report describes a rare case of recurrent head and neck desmoplastic neurotropic melanoma with perineural spread along the nervus mandibularis. An 87-year-old male presented with a rapidly growing mass on the right side of the chin, 4 years after surgical excision of a desmoplastic non-melanotic melanoma of the tip of the chin, with lymphadenectomy of the right side submental and submandibular areas. A panoramic X-ray showed extensive widening of the mandibular canal compatible with perineural tumour growth. (18)F-fluorodeoxyglucose ((18)F-FDG) positron emission tomography/computed tomography (PET/CT) images revealed intense pathological uptake in the recurrent tumour mass located in the right lower buccal fold, and linear pathological uptake in the mandibular canal. Although magnetic resonance imaging is considered the standard of reference, recognition of perineural spread on (18)F-FDG PET/CT is important, as it usually leads to a change in patient management from cure to palliation and may avert further diagnostic procedures.

Early recognition of aortitis of the aorta ascendens with ¹8F-FDG PET/CT: syphilitic?

We present the case of a 42-year-old woman known with a human leukocyte antigen B27 positive ankylosing spondylitis. Despite treatment with a tumor necrosis factor blocking agent, the patient was not pain free and inflammation markers remained elevated. An (18)F-fluorodeoxyglucose positron emission tomography/computed tomography ((18)F-FDG PET/CT) was performed in an attempt to exclude possible other inflammatory processes. The (18)F-FDG PET/CT revealed increased metabolic activity in the ascending aortic wall, which appeared unexpectedly related to late syphilis. Based on this case and existing literature on this subject, we come to the conclusion that (18)F-FDG PET/CT can help in an early establishment of syphilitic aortitis before the possible life-threatening sequelae of syphilitic aortitis occur.

Parameters related to a positive test result for FDG PET(/CT) for large vessel vasculitis: a multicenter retrospective study.

The purpose of this study was to identify clinical and laboratory parameters that may improve the effectiveness of the use of fluorodeoxyglucose positron emission tomography ((18)F-FDG PET)(/CT) for diagnosing large vessel vasculitis (LVV), and secondarily to assess the contribution of (18)F-FDG PET/CT in finding other diagnoses for patients without signs of LVV on the scan. A multicenter retrospective study of (18)F-FDG PET(/CT) scans performed between January 2000 and December 2009 for clinical suspicion of LVV was conducted. A total of 304 (18)F-FDG PET(/CT) scans were included, of which 62 (20%) were positive and 242 (80%) were negative for LVV. Univariate analysis showed that patients with a positive scan were older (65.9 ± 13.4 versus 58.6 ± 16.5 years, p = 0.002), were more frequently female (76% versus 55%, p = 0.002), more often had a history of temporal arteritis (10% versus 3%, p = 0.044), less frequently had artralgia (31% versus 67%, p = 0.000), and had higher thrombocyte counts (434 ± 161 versus 373 ± 168 × 10(9)/l, p = 0.049) and a higher erythrocyte sedimentation rate (ESR) (72.6 ± 31.0 versus 51.4 ± 30.5 mm/h, p = 0.001) than patients with a negative scan. In the multivariate analysis, only artralgia (OR 0.091; 95% CI 0.023-0.366) and ESR (OR 1.024; 95% CI 1.002-1.046) remained statistically significant predictors. The presence of artralgia is a statistically significant negative predictor and an elevated ESR a statistically significant positive predictor of LVV showing up on (18)F-FDG PET(/CT). A reliable prediction of the outcome of the scan, based on these two parameters, is not possible however. (18)F-FDG PET(/CT) allows early diagnosis of LVV and may discover occult inflammatory or neoplastic disorders.

A Rationale for the Use of F18-FDG PET/CT in Fever and Inflammation of Unknown Origin.

This review focuses on the diagnostic value of hybrid F18-FDG Positron Emission Tomography/Computerized tomography (PET/CT) in fever of unknown origin (FUO) and inflammation of unknown origin (IUO). Due to the wide range of possible causes both FUO and IUO remain a clinical challenge for both patients and physicians. In addition, the aetiology of IUO shows the same variation in diseases as the FUO spectrum and probably requires the same diagnostic approach as FUO. There are numerous historically used diagnostic approaches incorporating invasive and non-invasive, and imaging techniques, all with relative high specificity but limited sensitivity. This hampers the generalization of these diagnostic approaches. However, recently published reports show that F18-FDG PET/CT in FUO and IUO has a high sensitivity and a relative non-specificity for malignancy, infection and inflammation. This makes F18-FDG PET/CT an ideal diagnostic tool to start the diagnostic process and to guide subsequent focused diagnostic approaches with higher specificity. In addition, F18-FDG PET/CT has a relative high negative predictive value. Therefore F18 FDG PET/CT should be incorporated in the routine diagnostic work-up of patients with FUO and IUO, preferably at an early stage in the diagnostic process.

Performance of 18F-FDG PET/contrast-enhanced CT in the staging of squamous cell carcinoma of the oral cavity and oropharynx.

The aim of this study was to assess the diagnostic value of integrated whole body positron emission tomography/contrast-enhanced CT (PET/CECT) as a one step examination in the initial staging of oral and oropharyngeal squamous cell carcinoma (OOSCC). Seventy three consecutive OOSCC patients who underwent PET/CECT for initial staging and tumour resection and neck dissection as primary treatment, were included. For each PET/CECT result, the contribution of fluorine-18 fluorodeoxyglucose ((18)F-FDG)-uptake and radiologic criteria was assessed. PET/CECT results were correlated to histological specimens obtained with tumour resection and neck dissection. For detecting the primary tumour PET/CECT showed a sensitivity of 96% and for detecting cervical metastases a sensitivity and specificity of 89% and 81%, respectively. In the clinically N0 subgroup (n=37), PET/CECT showed a sensitivity and specificity of 64% and 81%, respectively. In five of six patients PET/CECT detected a second primary tumour. The results show that the use of diagnostic PET/CECT as a one step examination is a reliable alternative for PET/CT in combination with a separate diagnostic CT in patients with OOSC for initial staging. The need for treatment of the neck in the clinically negative neck should not be based on PET/CECT results only, due to the risk of missing a small metastasis.

The role of PET/CT in Cogan's syndrome.

We report on the case of a 60-year-old woman with complaints of fatigue, coughing, anorexia, atypical chest pain, recurrent fever, and also ear pain and hearing loss. A test for anti-neutrophil cytoplasmic antibody (ANCA) was myeloperoxidase positive with p-ANCA specificity. Laboratory acute phase parameters were increased. A 2-deoxy-2-[(18)F]fluoro-D: -glucose positron emission tomography/computed tomography investigation showed pathological uptake in the aorta ascendens, with no other involvement of the large vessels. After therapy with methylprednisolon intravenously and later prednisolon orally with methothrexate, her general condition and hearing loss improved both subjectively and objectively. "Atypical" Cogan's syndrome was diagnosed on the basis of sensorineural deafness with improvement on steroids and large-vessel vasculitis of the aortic arch.

[The value of PET-CT imaging in malignant tumours of the head and neck]. / De waarde van PET-cT-onderzoek bij maligne tumoren in het hoofd-halsgebied.

Imaging with fluor-18-deoxyglucose(FDG)-positron-emission tomography (PET) and CT combined in a single machine is a recent development. Using this technique both molecular and anatomical information are acquired. This results in an increased sensitivity and specificity in comparison to PET and CT as a single modality. One of the main advantages is that interpretation of PET images can be related to the anatomical information which helps to delineate the size and extent of a tumour as well as its relationship with surrounding tissues. It is also useful in planning surgical treatment and irradiation. At restaging PET-CT delineates the site and extent of a recurrence in the complex anatomy of the head and neck region and helps to define the location of a biopsy. This is particularly valuable in the anatomically complex head and neck region. Whole-body imaging can detect distant metastases and second primary tumours. PET-CT has the potential to become a part of the staging procedure of the primary tumour and also the follow-up in patients who have been treated for head and neck cancer.

Periumbilical uptake of Tc-99m MAA on lung perfusion scanning in a patient with superior vena cava obstruction.

A 25-year-old woman with severe parenchymal lung disease of unknown etiology and existing for more than a decade was referred for ventilation-perfusion scintigraphy because of suspicion of pulmonary embolism. Both ventilation and perfusion images showed, apart from perfusion defects from her severe lung disease, a left apical pneumothorax and signs of recurrent pneumonia of the left lower lobe. Noteworthy was the periumbilical uptake of the Tc-99m macroaggregated albumin (MAA). Her medical history revealed iatrogenic superior vena cava (SVC) obstruction. In this case, the main collateral pathway of portosystemic shunting is probably, after recanalization of the left umbilical vein, a network of smaller paraumbilical veins.

Captopril renography and the relevance of abnormal but bilateral identical curves in the diagnosis of renal artery stenosis.

BACKGROUND: Captopril renography (CR) has been shown to improve the effectiveness of renal scintigraphy in renovascular hypertension, by inhibiting angiotensin-converting enzyme. CR is particularly sensitive and specific in unilateral renal artery stenosis (RAS), but results in patients with bilateral RAS are less favourable. The aim of this study was to investigate the meaning of abnormal but identical renographic curves in the diagnosis of RAS. PATIENTS AND METHODS: One hundred and fifty-eight patients clinically suspected for renovascular hypertension underwent CR, using 50 MBq (99)Tc(m)-mercaptoacetyltriglycine ((99)Tc(m)-MAG(3)), prior to performing renal angiography. CR was performed 1 h after captopril administration. Renograms were analysed according to the consensus criteria. All patients underwent angiography, considered as the "gold standard" in the detection of the presence of RAS (stenosis >50% was defined as significant). All kidneys were categorized into three groups, scintigraphically as well as angiographically: no stenosis, unilateral stenosis and bilateral stenosis. RESULTS: Out of 158 patients 100 (63%) showed a RAS on angiography (58 (37%) unilateral, 42 (26%) bilateral). The sensitivity and specificity of CR evaluated by patient was 83% and 75%, respectively. Thirty patients with completely identical curves were identified, 21 patients with normal curves and nine patients with abnormal identical curves. All but one patient showed no RAS on the angiogram. In this single patient a unilateral stenosis was found. CONCLUSION: Identical curves on the renogram generally suggest no RAS and are probably due to intrinsic parenchymal disease.