Loukia S. Poulou

Percutaneous microwave ablation vs radiofrequency ablation in the treatment of hepatocellular carcinoma

Hepatocellular cancer ranks fifth among cancers and is related to chronic viral hepatitis, alcohol abuse, steatohepatitis and liver autoimmunity. Surgical resection and orthotopic liver transplantation have curative potential, but fewer than 20% of patients are suitable candidates. Interventional treatments are offered to the vast majority of patients. Radiofrequency (RFA) and microwave ablation (MWA) are among the therapeutic modalities, with similar indications which include the presence of up to three lesions, smaller than 3 cm in size, and the absence of extrahepatic disease. The therapeutic effect of both methods relies on thermal injury, but MWA uses an electromagnetic field as opposed to electrical current used in RFA. Unlike MWA, the effect of RFA is partially limited by the heat-sink effect and increased impedance of the ablated tissue. Compared with RFA, MWA attains a more predictable ablation zone, permits simultaneous treatment of multiple lesions, and achieves larger coagulation volumes in a shorter procedural time. Major complications of both methods are comparable and infrequent (approximately 2%-3%), and they include haemorrhage, infection/abscess, visceral organ injury, liver failure, and pneumothorax. RFA may incur the additional complication of skin burns. Nevertheless, there is no compelling evidence for differences in clinical outcomes, including local recurrence rates and survival.

Unifying the predictive value of pretransplant FDG PET in patients with lymphoma: a review and meta-analysis of published trials

PurposeThe predictive value of 18F-FDG PET in patients with relapsing/refractory lymphoma who are receiving high-dose chemotherapy and autologous stem cell transplantation (ASCT) remains a matter of debate. Seminal reports on pretransplant ASCT indicated an adverse prognosis in patients with positive FDG PET scans. The lack of a uniform outcome measure along with the mixed histologies in various studies have hampered efforts to quantify this prognostic value.MethodsA MEDLINE review of published trials up to April 2009 identified 16 studies involving pretransplant FDG PET scans in lymphoma. Where progression-free survival (PFS) and overall survival (OS) were set as the main outcome measures, time-to-event data analysis was used to calculate the overall prognostic value of a pretransplant FDG-PET scan.ResultsPooled survival data from seven eligible studies suggested a worse PFS in patients with a positive FDG PET study (HR 3.23, 95% CI 2.14 to 4.87). The OS pooled from six eligible studies was also significantly worse among patients with a positive FDG PET study (HR 4.53, 95% CI 2.50 to 8.22). No statistically significant heterogeneity was observed between studies for either outcome.ConclusionDespite the documented clinical heterogeneity between studies, meta-analysis data confirmed the prognostic impact of pretransplant FDG PET in patients with lymphoma and provided a uniform measure of the association for both progression and survival after ASCT.

Thrombosis in Paroxysmal Nocturnal Hemoglobinuria at a Glance: A Clinical Review

Paroxysmal nocturnal hemoglobinuria (PNH) is a rare, acquired stem cell disorder, with its primary clinical manifestations being hemolytic anemia, marrow failure and thrombophilia. Chronic hemolysis, failures of the fibrinolytic system, increased leukocyte-derived tissue factor levels in plasma, procoagulant microparticles generated through complement-mediated damage of platelets and venous endothelium are related to the acquired hypercoagulable state. Visceral thrombosis (including hepatic veins and mesenteric veins), cerebrovascular events and pulmonary embolism predict a poor outcome. Thrombosis is also associated with significant morbidity during pregnancy. Depending on the sites of thrombosis, a score-based probability to predict outcome can be assigned. Abdominal vein thromboses account for the majority of morbidity and mortality related to thrombosis, and time-dependent trends suggest that mortality rates tend to decline, with the advent of evolution of therapeutic and diagnostic strategies. In contrast, mortality rates from cerebrovascular events display no significant decline. Prompt diagnosis requires both clinical suspicion and sophisticated imaging techniques, along with multidisciplinary therapeutic intervention. In the eculizumab era, a significant reduction of thrombotic events was observed during therapy, and long-term follow up is needed to establish any benefit in rates and pattern of this complication. However, up to now, only bone marrow transplantation permanently abolishes the coagulation defect.

FDG PET is a robust tool for the diagnosis of spondylodiscitis: a meta-analysis of diagnostic data.

Purpose Spondylodiscitis is a rare infectious entity that requires multimodal diagnostic procedures. We evaluated the diagnostic performance of 18F-FDG PET on suspected spondylodiscitis based on published literature. Patients and Methods We searched the PubMed and EMBASE for pertinent studies up to July 2013. We implemented a patient-based meta-analysis of diagnostic data for FDG PET (the index test) against clinical, laboratory, and/or radiologic evidence of disease (the reference standard). A bivariate analysis was implemented to account for variability beyond the threshold effect. The individual patient data analysis was used to assess confounding factors that moderate diagnostic performance. Results Twelve studies provided the diagnostic data on FDG PET and spondylodiscitis, comprising 224 patients. The combined sensitivity across studies was 0.97 [95% confidence interval (CI), 0.83–1.00], the specificity was 0.88 (95% CI, 0.74–0.95), and the area under the curve was 0.98 (95% CI, 0.96–0.99). For prior probabilities greater than 0.50, the corresponding positive predictive value was 0.96 (0.93–0.98), and the negative predictive value was 0.85 (0.82–0.88). In the individual patient data analysis, metallic implants, dual PET/CT scanners and the addition of other imaging modalities to confirm disease were significant outcome moderators; only PET/CT remained significant in the adjusted analysis. PET/CT scanners improved the diagnostic performance, as opposed to the clinical data (age, sex, lesion site), which did not alter outcome. Conclusions FDG PET is a robust diagnostic test when spondylodiscitis is suspected and is excellent for exclusion of infectious spondylodiscitis given its low likelihood ratio negative (<0.1). Importantly, this diagnostic test is unaffected by other confounders, including the presence of implants, when PET/CT is used.

Computed tomography-guided needle aspiration and biopsy of pulmonary lesions: a single-center experience in 1000 patients

Background Computed tomography (CT)-guided fine needle aspiration (FNA) and biopsies are well-established, minimally invasive diagnostic tools for pulmonary lesions. Purpose To analyze retrospectively the results of 1000 consecutive lung CT-guided FNA and/or core needle biopsies (CNB), the main outcome measures being diagnostic yield, and complication rates. Material and Methods Patients considered eligible were those referred to our department for lung lesions. The choice of FNA, CNB, or both was based upon the radiologists judgment. Diagnostic yield was defined as the probability of having a definite result by cytology/histology. Results The study included 733 male patients and 267 female patients, with a mean (SD) age of 66.4 (11.4) years. The mean (SD) lesion size was 3.7 (2.4) cm in maximal diameter. Six hundred and forty-one (64%) patients underwent an FNA procedure, 245 (25%) a CNB, and 114 (11%) had been subjected to both. The diagnostic yield was 960/994 (96.6%); this decreased significantly with the use of CNB only (odds ratio [OR] 0.32; 95% CI 0.12–0.88; P = 0.03), while it increased with lesion size (OR 1.35; 95% CI 1.03–1.79; P = 0.03 per cm increase). In 506 patients (52.7%), a malignant process was diagnosed by cytopathology/histology. The complication rate reached 97/1000 (9.7%); complications included: hemorrhage, 62 (6.2%); pneumothorax, 28 (2.8%); hemorrhage and pneumothorax, 5 (0.5%); and hemoptysis, 2 (0.2%). It was not significantly affected by the type of procedure or localization of the lesion. The overall risk for complications was three times higher for lesions <4 cm (OR 3.26; 95% CI 1.96–5.42; P < 0.001). Conclusion CT-guided lung biopsy has a high diagnostic yield using FNA, CNB, or both. The CNB procedure alone will not suffice. Complication rates were acceptable and correlated inversely with lesion size, not localization or type of procedure.

Temporal trends in mortality rates from visceral vein thrombosis in paroxysmal nocturnal haemoglobinuria: An optimistic view

Temporal trends in mortality rates from visceral vein thrombosis in paroxysmal nocturnal haemoglobinuria: An optimistic view -

Feasibility of CT-Guided Percutaneous Needle Biopsy in Early Diagnosis of BOOP

Bronchiolitis obliterans organizing pneumonia (BOOP) is a nonneoplastic, noninfectious lung disease with a diverse spectrum of imaging abnormalities and nonspecific symptoms diagnosed by open lung biopsy, transbroncial biopsy, and/or video-assisted thoracoscopy. The objective of this study was to retrospectively assess the role of percutaneous computed tomography (CT)-guided biopsy in early diagnosis of the disorder. Fourteen BOOP cases diagnosed by CT-guided biopsy were analyzed in terms of imaging abnormalities and complication rate. All had previously undergone a nondiagnostic procedure (bronchoscopy, transbronchial biopsy, bronchoalveolar lavage) to exclude infection or lung cancer. The most common imaging abnormalities in descending order were bilateral consolidations (5/14), unilateral tumor-like lesions (5/14), unilateral consolidations (3/14), and diffuse reticular pattern (1/14). Coexistent abnormalities (pleural effusions, nodules, ground-glass opacities) were observed in five patients. The complication rate was 4 of 14 (28.6%), including 2 cases of subclinical pneumothorax and 1 case of minor hemoptysis and local lung injury. None required intervention. We conclude that transthoracic CT-guided biopsy may be used in the diagnosis of BOOP in selected patients with mild complications. For the focal consolidation nodule/mass imaging pattern, CT-guided biopsy may prove to be a reasonable alternative to more invasive procedures.

Evaluating cognitive models of visual word recognition using fMRI: Effects of lexical and sublexical variables

In this study predictions of the dual-route cascaded (DRC) model of word reading were tested using fMRI. Specifically, patterns of co-localization were investigated: (a) between pseudoword length effects and a pseudowords vs. fixation contrast, to reveal the sublexical grapho-phonemic conversion (GPC) system; and (b) between word frequency effects and a words vs. pseudowords contrast, to reveal the orthographic and phonological lexicon. Forty four native speakers of Greek were scanned at 3T in an event-related lexical decision task with three event types: (a) 150 words in which frequency, length, bigram and syllable frequency, neighborhood, and orthographic consistency were decorrelated; (b) 150 matched pseudowords; and (c) fixation. Whole-brain analysis failed to reveal the predicted co-localizations. Further analysis with participant-specific regions of interest defined within masks from the group contrasts revealed length effects in left inferior parietal cortex and frequency effects in the left middle temporal gyrus. These findings could be interpreted as partially consistent with the existence of the GPC system and phonological lexicon of the model, respectively. However, there was no evidence in support of an orthographic lexicon, weakening overall support for the model. The results are discussed with respect to the prospect of using neuroimaging in cognitive model evaluation.

The Gordian knot of interim 18-fluorodeoxyglucose positron emission tomography for Hodgkin lymphoma: a meta-analysis and commentary on published studies

Abstract We assessed the diagnostic performance of interim 18-fluorodeoxyglucose positron emission tomography (FDG-PET) with regard to the final outcome of adult patients with newly diagnosed Hodgkin lymphoma (HL). The predefined outcome was treatment failure at the end of follow-up. Bivariate meta-analysis of diagnostic data was used to calculate combined (pooled) estimates. Demographics, quality data and study characteristics were used as potential moderators of outcome in subgroup analysis and meta-regression. A total of 14 studies (16 arms stratified by staging or therapy, 1328 evaluable patients) were deemed eligible for final analysis, after excluding intention-to-treat studies (i.e. those where treatment decision was based on interim PET). The combined effect (95% confidence interval) for sensitivity was 0.67 (0.57–0.76) and specificity 0.89 (0.84–0.93). The corresponding likelihood ratios (LRs) were 6.2 (3.9–10.0) for LR + and 0.37 (0.27–0.50) for LR −, with moderate heterogeneity (I2 =67%). The estimated negative predictive value was 0.93 (0.85–1.00). The diagnostic performance was influenced by most covariates tested, including age, duration of follow-up, criteria used and time of interim PET. Interim PET retains a high specificity for final outcome, but the sensitivity is low. The use of a PET + study as a surrogate marker is hampered by inconsistent interpretation criteria and study populations. However, the high negative predictive value may permit treatment stratification based on a negative outcome.

FDG PET scan strategies and long-term outcomes after first-line therapy in Hodgkin's Disease

BACKGROUND The use of positron emission tomography with fluoro-deoxy-glucose (FDG PET) in Hodgkins disease (HD) is continuing to expand worldwide, with response assessment after completion of therapy being its most widely utilized application. A positive scan has been associated with high relapse rates and disease progression. METHODS A decision analysis was performed to determine the long-term impact of FDG PET restaging both with and without computed tomography (CT) in terms of the 5-year progression-free survival (5yrPFS). Outcomes and utilities were based on published data. The first strategy involved CT restaging after first-line therapy, with or without subsequent FDG PET, while the second strategy used FDG PET scan alone. All positive test required histological examination. Upon histological confirmation of active lymphoma, patients were considered candidates for autologous transplantation and long-term outcomes were retrieved. The expected clinical benefit of the two strategies was calculated and depicted, along with the mean costs. One-way and two-way sensitivity analyses were performed to ensure the validity of the results. RESULTS CT restaging plus FDG PET when residual mass is detected, results in a 2% benefit at 5yrPFS at baseline compared to FDG PET-alone restaging and remains positive for a wide range of probabilities. This strategy reduces the average cost by euro 1863 per patient, including costs of biopsy and autologous transplantation. CONCLUSION A more conservative approach that includes CT restaging after first-line therapy and FDG PET scan only on residual mass, is the preferred strategy in HD. Furthermore it appears to confer the maximal diagnostic yield along with a substantial reduction in the mean cost.