Diagnostic accuracy of SSR-PET/CT compared to histopathology in the identification of liver metastases from well-differentiated neuroendocrine tumors.

BACKGROUND: Histopathology is the reference standard for diagnosing liver metastases of neuroendocrine tumors (NETs). Somatostatin receptor-positron emission tomography / computed tomography (SSR-PET/CT) has emerged as a promising non-invasive imaging modality for staging NETs. We aimed to assess the diagnostic accuracy of SSR-PET/CT in the identification of liver metastases in patients with proven NETs compared to histopathology. METHODS: Histopathologic reports of 139 resected or biopsied liver lesions of patients with known NET were correlated with matching SSR-PET/CTs and the positive/negative predictive value (PPV/NPV), sensitivity, specificity, and diagnostic accuracy of SSR-PET/CT were evaluated. PET/CT reading was performed by one expert reader blinded to histopathology and clinical data. RESULTS: 133 of 139 (95.7%) liver lesions showed malignant SSR-uptake in PET/CT while initial histopathology reported on 'liver metastases of NET´ in 127 (91.4%) cases, giving a PPV of 91.0%. Re-biopsy of the initially histopathologically negative lesions (reference standard) nevertheless diagnosed 'liver metastases of NET' in 6 cases, improving the PPV of PET/CT to 95.5%. Reasons for initial false-negative histopathology were inadequate sampling in the sense of non-target biopsies. The 6 (4.3%) SSR-negative lesions were all G2 NETs with a Ki-67 between 2-15%. CONCLUSION: SSR-PET/CT is a highly accurate imaging modality for the diagnosis of liver metastases in patients with proven NETs. However, we found that due to the well-known tumor heterogeneity of NETs, specifically in G2 NETs approximately 4-5% are SSR-negative and may require additional imaging with [18F]FDG PET/CT.

The diagnostic value of contrast-enhanced ultrasound (CEUS) for assessing hepatocellular carcinoma compared to histopathology; a retrospective single-center analysis of 119 patients1.

BACKGROUND: HCC as the 6th most common tumor entity with the fourth highest mortality and an increasing prevalence especially due to today's lifestyle acquires a high attention in the clinical setting. Beside CECT and CEMRI, CEUS depicts a dynamic, low-risk and radiation free imaging method that finds its use mainly in screening and active surveillance programs. PURPOSE: The aim of the retrospective study was to evaluate the diagnostic value of CEUS in correlation to pathologic findings. MATERIALS AND METHODS: Between 2004 and 2018 a total number of 119 patients were included in this retrospective single-center study. Every patient underwent CEUS in addition to a native B-mode and Color-Doppler scan. After given informed consent SonoVue® (Bracco, Milan, Italy), a second-generation blood-pool agent, was used as contrast medium. Every examination was performed and interpreted by a single experienced radiologist (EFSUMB level 3). A low mechanical index (MI) of <0,2 was chosen to obtain a good imaging quality. RESULTS: All 119 included patients received CEUS followed by a liver biopsy for inter-modality comparison. In correlation to the pathology results, CEUS showed a diagnostic sensitivity of 96,6%, a specificity of 63,9%, a PPV of 86,7% and a NPV of 88,5% by detecting liver lesions suspicious for HCC. According to the Cohen's Kappa coefficient (k = 0,659) CEUS shows a strong inter-modality agreement in comparison to the histopathological finding. CONCLUSION: With a high sensitivity and a strong cross-modality comparability to histopathology, the CEUS is highly effective in the detection of suspicious HCC lesions.

The regression hypothesis: communicative continuum vs. parametrically defined grammars.

Proposals concerning the regression hypothesis in aphasia presented in Grodzinsky (1990) and Schnitzer (1989, 1990) are compared. It is argued that Grodzinsky's model, which is syndrome-based, is observationally inadequate, and thus fails to lend aphasiological support to a neurophysiologically realized central language system along the lines of Chomsky's Theory of Principles and Parameters. Schnitzer's approach rejects the notion of mental grammars and interprets aphasic regression microgenetically, along the lines of Givón's continuum. It is argued that this approach has the potential to become truly explanatory.

The development of segmental phonological production in a bilingual child.

A longitudinal diary-and-videotape study of the production of phonological segments by a Spanish-English bilingual child, age I; I-3; 9, revealed four stages in consonantal acquisition: presystematic variation, formation of a single system, separation into two systems corresponding to the two languages, and achievement of adult target values with later interference of one language in the other. Vocalic acquisition proceeded with widespread variation, followed by stabilization at target adult values, without any apparent intermediate unitary-system stage. Relevance of the data adduced here to the issue of whether bilingual children first function with a single system before acquiring two discrete languages is discussed. The issue of what it may mean to have one or two systems of phonology is addressed.

Steady as a rock: does the steady state represent cognitive fossilization?

A study was performed in which data were obtained from adults and children with respect to their control of the inflexional morphology of the Spanish verbal system. Results indicate that adults have inferior knowledge of the paradigm compared to the children. Based on the types of errors committed, it is argued that linguistic knowledge may be more an ability to analogize correctly than to follow (unconscious) rules. Implications for GB (Government and Binding) theory and first and second language acquisition are discussed.

Pragmatic-mode mediation of sentence comprehension among aphasic bilinguals and hispanophones.

A test of sentence comprehension administered in four input-output modality combinations to a group of aphasic bilinguals and monolingual hispanophones provides evidence that aphasics tend to use pragmatic-mode (in the sense of Givón, 1979, On understanding-grammar, New York, Academic Press) strategies in approaching this task. When five factors were identified and dichotomized with respect to the pragmatic-mode-syntactic-mode dimension, the patients performed significantly better on items classified as pragmatic than on those classified as syntactic, in both languages. The results support a vertical/hierarchical view of aphasic language dissolution.