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.

Cost-effectiveness analysis of MRI, CE-CT and 18F-FDG PET/CT for detecting colorectal liver metastases eligible for hepatic resection

OBJECTIVES

Colorectal cancer (CRC) is a serious challenge for the health system. In 2022 CRC represented 8% of cancer diagnoses in the United States. 30% of patients already show metastases at the initial tumor staging. The majority of these metastases are sited in the liver. According to their extension and the status of the tumor colorectal liver metastases can be treated in several ways, with hepatic resection being the gold-standard. Contrast-enhanced computed tomography (CE-CT), positron emission tomography/computed tomography (PET/CT) and magnetic resonance imaging (MRI) can be used for evaluation of resectability of these liver metastases. The aim of this study is to assess the most economic imaging modality for detecting liver metastases eligible for hepatic resection by analyzing their cost-effectiveness.

MATERIALS AND METHODS

In our study, a Markov state transition model was built to calculate the quality-adjusted life years (QALYs) and overall costs for each diagnostic strategy in accord with the stated input values obtained from scientific research. Further, probabilistic sensitivity analyses by means of Monte Carlo simulations were performed to consider possible model uncertainties. For evaluation of the cost-effectiveness on an economic threshold, the Willingness-to-pay (WTP) was set at $ 100,000. The applied values and the calculated results are based on the U.S. healthcare system.

RESULTS

CE-CT led to overall costs of $ 42,874.02 and 8.47 QALYs, whereas MRI led to $ 40,863.65 and 8.50 QALYs. PET/CT resulted in overall costs of $ 43,216.74 and 8.48 QALYs. Therefore, MRI was determined to be the dominant strategy in the model. According to the performed sensitivity analyses, MRI remained cost-effective over a wide range of WTPs.

CONCLUSION

In conclusion, according to our analysis, MRI is the dominant strategy for detecting hepatic metastases eligible for hepatic resection in colorectal cancer.

Economic evaluation of 18F-FDG PET/CT, MRI and CE-CT in selection of colorectal liver metastases eligible for ablation – A cost-effectiveness analysis

OBJECTIVES

Colorectal cancers (CRC) are among the world's most prevailing cancer entities. In a third of all cases, the patients have already developed distant metastases - mainly in the liver - at the time of detection. Colorectal liver metastases (CRLM) can be treated by surgical resection or, as is possible in most cases, by percutaneous ablation. For selecting the liver metastases eligible for radiofrequency ablation (RFA) or microwave ablation (MWA), the common imaging modalities are magnetic resonance imaging (MRI), positron emission tomography/computed tomography (PET/CT), and contrast-enhanced computed tomography (CE-CT). This study aims to evaluate those imaging modalities for selecting liver lesions eligible for ablation according to their long-term cost-effectiveness.

MATERIALS AND METHODS

A Markov model was applied, calculating quality-adjusted life years (QALYs) and accumulative costs for every diagnostic strategy, according to predefined input parameters obtained from published research. Further, sensitivity analyses were executed to prove the certainty of the calculations by running Monte-Carlo simulations with 30,000 reiterations. The Willingness-to-pay (WTP) is at $ 100,000. All calculations are based on the U.S. healthcare system.

RESULTS

CE-CT caused cumulative costs of $ 31,940.98 and 8,99 QALYs, whereas MRI caused $ 32,070.83 and 9,01 QALYs. PET/CT caused cumulative costs of $ 33,013.21 and 8,99 QALYs.

CONCLUSION

In conclusion, according to our analysis, MRI is the most cost-effective strategy for detecting liver metastases eligible for ablation and therefore should be seen as the gold standard.

Economic potential of abbreviated breast MRI for screening women with dense breast tissue for breast cancer

OBJECTIVES

Abbreviated breast MRI (AB-MRI) was introduced to reduce both examination and image reading times and to improve cost-effectiveness of breast cancer screening. The aim of this model-based economic study was to analyze the cost-effectiveness of full protocol breast MRI (FB-MRI) vs. AB-MRI in screening women with dense breast tissue for breast cancer.

METHODS

Decision analysis and a Markov model were designed to model the cumulative costs and effects of biennial screening in terms of quality-adjusted life years (QALYs) from a US healthcare system perspective. Model input parameters for a cohort of women with dense breast tissue were adopted from recent literature. The impact of varying AB-MRI costs per examination as well as specificity on the resulting cost-effectiveness was modeled within deterministic sensitivity analyses.

RESULTS

At an assumed cost per examination of $ 263 for AB-MRI (84% of the cost of a FB-MRI examination), the discounted cumulative costs of both MR-based strategies accounted comparably. Reducing the costs of AB-MRI below $ 259 (82% of the cost of a FB-MRI examination, respectively), the incremental cost-effectiveness ratio of FB-MRI exceeded the willingness to pay threshold and the AB-MRI-strategy should be considered preferable in terms of cost-effectiveness.

CONCLUSIONS

Our preliminary findings indicate that AB-MRI may be considered cost-effective compared to FB-MRI for screening women with dense breast tissue for breast cancer, as long as the costs per examination do not exceed 82% of the cost of a FB-MRI examination.

KEY POINTS

• Cost-effectiveness of abbreviated breast MRI is affected by reductions in specificity and resulting false positive findings and increased recall rates. • Abbreviated breast MRI may be cost-effective up to a cost per examination of 82% of the cost of a full protocol examination. • Abbreviated breast MRI could be an economically preferable alternative to full protocol breast MRI in screening women with dense breast tissue.

Economic assessment of molecular imaging in the oncology treatment process

The development towards targeted treatments in oncology has been accompanied by significant improvements in molecular imaging. Yet, broad application of novel imaging techniques has partly been slowed down due to economical considerations. Building on the broad positive evidence of its diagnostic accuracy, modelling of effects on long-term costs and effectiveness may help to foster a broader application and acceptance of comprehensive molecular imaging techniques, such as PET/MRI. In this article, common economic evaluation techniques and cost-effectiveness analysis (CEA) evaluation methods will be introduced including Markov models and incremental cost-effectiveness ratios (ICER). This is complemented with a review of literature on recently published cost-effectiveness of molecular imaging. Additionally, the strategic relevance of CEAs for the molecular imaging community is discussed and combined with a global outlook.

Cost-Effectiveness of MR-Mammography in Breast Cancer Screening of Women With Extremely Dense Breasts After Two Rounds of Screening

Objectives

To evaluate the cost-effectiveness of MR-mammography (MRM) vs. x-ray based mammography (XM) in two-yearly screening women of intermediate risk for breast cancer in the light of recent literature.

Methods

Decision analysis and Markov modelling were used to compare cumulative costs (in US-$) and outcomes (in QALYs) of MRM vs. XM over the model runtime of 20 years. The perspective of the U.S. healthcare system was selected. Incremental cost-effectiveness ratios (ICER) were calculated and related to a willingness to pay-threshold of $ 100,000 per QALY in order to evaluate the cost-effectiveness. Deterministic and probabilistic sensitivity analyses were conducted to test the impact of variations of the input parameters. In particular, variations of the rate of false positive findings beyond the first screening round and their impact on cost-effectiveness were assessed.

Results

Breast cancer screening with MRM resulted in increased costs and superior effectiveness. Cumulative average costs of $ 6,081 per woman and cumulative effects of 15.12 QALYs were determined for MRM, whereas screening with XM resulted in costs of $ 5,810 and 15.10 QALYs, resulting in an ICER of $ 13,493 per QALY gained. When the specificity of MRM in the second and subsequent screening rounds was varied from 92% to 99%, the ICER resulted in a range from $ 38,849 to $ 5,062 per QALY.

Conclusions

Based on most recent data on the diagnostic performance beyond the first screening round, MRM may remain the economically preferable alternative in screening women of intermediate risk for breast cancer due to their dense breast tissue.

Cost-effectiveness analysis in radiology: methods, results and implications

BACKGROUND

 Diagnostic radiological examinations as well as interventional radiological therapies are performed at a steadily increasing rate amidst increasingly limited resources in healthcare systems. Given their potential to contribute decisively to optimized therapy, in most cases associated short-term direct costs can be well justified from a clinical perspective. However, to realize their clinical benefits, they must also succeed in justifying them to payers and policymakers. Therefore, the aim of this work is to present suitable methods for economic analysis of radiological precedures and to elaborate their relevance for radiology.

METHODOLOGY

 Methods and metrics of cost-effectiveness analysis are presented and then exemplified using the example cases of MR mammography and interventional treatment of oligometastatic tumor disease of the liver.

RESULTS

 Cost-effectiveness considerations, taking into account long-term gains in lifespan and quality of life, as well as potential savings through improved treatment planning, do often objectively and credibly justify short-term additional costs.

CONCLUSIONS

 Cost-effectiveness analyses performed with radiological and health economic expertise can support the establishment of new radiological technologies in diagnostics and therapy.

KEY POINTS

  · When radiological procedures are employed, short-term costs are often offset by significant long-term benefits.. · Radiological examinations and therapies must be justified in the context of limited economic resources.. · Economic methodologies can be used to quantify the quality and cost-effectiveness of radiological methods.. · Such analyses as well as targeted training should be encouraged to provide greater transparency..

CITATION FORMAT

· Froelich MF, Kunz WG, Tollens F et al. Cost-effectiveness analysis in radiology: methods, results and implications. Fortschr Röntgenstr 2021; DOI: 10.1055/a-1502-7830.

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.

Structured Reporting in the Characterization of Renal Cysts by Contrast-Enhanced Ultrasound (CEUS) Using the Bosniak Classification System-Improvement of Report Quality and Interdisciplinary Communication

BACKGROUND

This study aims to evaluate the potential benefits of structured reporting (SR) compared to conventional free-text reporting (FTR) in contrast-enhanced ultrasound (CEUS) of cystic renal lesions, based on the Bosniak classification.

METHODS

Fifty patients with cystic renal lesions who underwent CEUS were included in this single-center study. FTR created in clinical routine were compared to SR retrospectively generated by using a structured reporting template. Two experienced urologists evaluated the reports regarding integrity, effort for information extraction, linguistic quality, and overall quality.

RESULTS

The required information could easily be extracted by the reviewers in 100% of SR vs. 82% of FTR (p < 0.001). The reviewers trusted the information given by SR significantly more with a mean of 5.99 vs. 5.52 for FTR (p < 0.001). SR significantly improved the linguistic quality (6.0 for SR vs. 5.68 for FTR (p < 0.001)) and the overall report quality (5.98 for SR vs. 5.58 for FTR (p < 0.001)).

CONCLUSIONS

SR significantly increases the quality of radiologic reports in CEUS examinations of cystic renal lesions compared to conventional FTR and represents a promising approach to facilitate interdisciplinary communication in the future.

Diagnostic Performance of Contrast-Enhanced Ultrasound (CEUS) in the Evaluation of Solid Renal Masses

Background: The present study aims to evaluate the diagnostic performance of contrast-enhanced ultrasound (CEUS) for discriminating between benign and malignant solid renal masses. Methods: 18 patients with histopathologically confirmed benign solid renal masses (11 oncocytomas, seven angiomyolipomas) as well as 96 patients with confirmed renal cell carcinoma (RCC) who underwent CEUS followed by radical or partial nephrectomy were included in this single-center study. CEUS examinations were performed by an experienced radiologist (EFSUMB Level 3) and included the application of a second-generation contrast agent. Results: Renal angiomyolipomas, oncocytomas, and renal cell carcinomas showed varying sonomorphological characteristics in CEUS. Angiomyolipomas showed heterogeneous echogenicity (57% hypo-, 43% hyperechoic), while all lesions showed rapid contrast-enhancement with two lesions also showing venous wash-out (29%). Notably, 9/11 oncocytomas could be detected in conventional ultrasound (64% hypo-, 9% hyper-, 9% isoechoic) and 2/11 only demarcated upon intravenous application of contrast agent (18%). All oncocytomas showed hyperenhancement in CEUS, venous wash-out was registered in 7/11 lesions (64%). Conclusions: In line with the current state of knowledge, no specific sonomorphological characteristics allowing for accurate distinction between benign and malignant solid renal masses in CEUS could be detected in our study.

Follow-Up 18F-FDG PET/CT versus Contrast-Enhanced CT after Ablation of Liver Metastases of Colorectal Carcinoma-A Cost-Effectiveness Analysis

PURPOSE

After a percutaneous ablation of colorectal liver metastases (CRLM), follow-up investigations to evaluate potential tumor recurrence are necessary. The aim of this study was to analyze whether a combined 18F-Fluordesoxyglucose positron emission tomography-computed tomography (18F-FDG PET/CT) scan is cost-effective compared to a contrast-enhanced computed tomography (CE-CT) scan for detecting local tumor progression.

MATERIALS AND METHODS

A decision model based on Markov simulations that estimated lifetime costs and quality-adjusted life years (QALYs) was developed. Model input parameters were obtained from the recent literature. Deterministic sensitivity analysis of diagnostic parameters based on a Monte-Carlo simulation with 30,000 iterations was performed. The willingness-to-pay (WTP) was set to $100,000/QALY.

RESULTS

In the base-case scenario, CE-CT resulted in total costs of $28,625.08 and an efficacy of 0.755 QALYs, whereas 18F-FDG PET/CT resulted in total costs of $29,239.97 with an efficacy of 0.767. Therefore, the corresponding incremental cost-effectiveness ratio (ICER) of 18F-FDG PET/CT was $50,338.96 per QALY indicating cost-effectiveness based on the WTP threshold set above. The results were stable in deterministic and probabilistic sensitivity analyses.

CONCLUSION

Based on our model, 18F-FDG PET/CT can be considered as a cost-effective imaging alternative for follow-up investigations after percutaneous ablation of colorectal liver metastases.

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.