[Elastography in thyroid nodules]. / Elastografie von Schilddrüsenknoten.

BACKGROUND: Elastography is an imaging method to examine the elasticity of tissue. In the meantime, various elastography methods have been developed, which are subdivided according to the type of stimulus applied. In principle, a distinction should be made between strain elastography (SE) and shear wave elastography (SWE). Both methods provide another means of assessing thyroid disease in addition to conventional B-mode sonography. OBJECTIVE: The aim is to provide an overview of elastography techniques including physical basics and their importance in the clarification algorithm of thyroid nodules. MATERIALS AND METHODS: International guidelines and recent publications on elastography were selectively assessed. RESULTS: Elastography provides additional information compared to conventional B-mode sonography. The change in shear stiffness is the essential physical mechanism for tissue contrast in all elastograms. In addition to the qualitative assessment of elasticity in SE, quantification is possible with SWE. In the international literature, elastography was analyzed as a single method or in comparison or combination with conventional B-mode sonography and especially with standardization using a risk stratification system (RSS, TIRADS). The results are quite controversial. In nodules with unclear findings on fine-needle biopsy (Bethesda III/IV), the combination of morphologic criteria and elastography improved diagnostic accuracy. In particular, the high negative predictive value of soft nodules represents a relevant added value. This strength of the method can play an important role in the clarification of nodules with intermediate malignancy risk or of unclear FNB results. Elastography has previously only been incorporated into French-TIRADS. Although the procedure is mentioned in the EU-TIRADS as a complementary method, integration has not been described. Limitations of the method are idealized basic assumptions, dependence of manufacturer and examiner, and artifacts. CONCLUSION: Elastography can be a useful adjunct to standard diagnostic procedures in the evaluation of thyroid nodules, especially in nodules with intermediate risk of malignancy and unclear results on fine needle aspiration.

Thyroid scintigraphy: establishing a clinically useful normal range for 99mTc pertechnetate uptake.

PURPOSE: This study aims to establish a normal range for the thyroid uptake derived from 99mTc pertechnetate scans. In particular, variations of uptake with TSH stimulation and other factors such as urinary iodine concentration are taken into account and compared with the calculation of a raw uptake value. METHODS: Clinical multicentric (center A, B and C) prospective study on 125 consecutive healthy patients undergoing thyroid scans for thyroid nodules. Normal functional thyroid status was assured by normal TSH, normal thyroid size, no thyroid antibodies and no symptoms of thyroid functional disorders. Calculations of raw Tc-uptake (uptake) and modified uptake values regarding current TSH value (uptakeTSH1), urinary iodine concentration (uptakeTSH1&uic), gland volume, age, smoking status, weight and tissue thickness ventral to the thyroid were performed. RESULTS: There is a positive correlation of thyroid uptake with TSH allowing for the calculation of a normalized uptake value (uptakeTSH1). The normal range for uptakeTSH1 compares favourable to that for raw uptake in that it yields a clear distinction from thyroid functional disorders. The additional normalization for urinary iodine concentration (uptakeTSH1&uic) may even improve the distinctive power whereas further normalizations such as for gland volume, age and others are not warranted by this study. The 95% CI of uptakeTSH1 for sites A, A&B, and A&B&C were 0.21%-2.06%, 0.22%-2.38% and 0.24%-2.40%. CONCLUSION: A normal range for the thyroid uptake can be established with respect to the current TSH stimulation. This normalization (uptakeTSH1) overcomes the drawback of raw uptake by yielding a clinically useful parameter with obviously high distinctive power against functional thyroid disorders.

Correct and Incorrect Recommendations for or against Fine Needle Biopsies of Hypofunctioning Thyroid Nodules: Performance of Different Ultrasound-based Risk Stratification Systems.

PURPOSE: To evaluate the recommendations for or against fine needle biopsy (FNB) of hypofunctioning thyroid nodules (TNs) using of five different Ultrasound (US) -based risk stratification systems (RSSs). METHODS: German multicenter study with 563 TNs (≥ 10 mm) in 534 patients who underwent thyroid US and surgery. All TNs were evaluated with ACR TI-RADS, EU-TIRADS, ATA, K-TIRADS 2016 and modified K-TIRADS 2021. A correct recommendation was defined as: malignant TN with recommendation for FNB (appropriate) or benign TN without recommendation for FNB (avoided). An incorrect recommendation was defined as: malignant TN without recommendation for FNB (missed) or benign TN with recommendation for FNB (unnecessary). RESULTS: ACR TI-RADS demonstrated the highest rate of correct (42.3 %) and lowest rate of incorrect recommendations (57.7 %). The other RRSs showed similar results for correct (26.5 %-35.7 %) and incorrect (64.3 %-73.5 %) recommendations. ACR TI-RADS demonstrated the lowest rate of unnecessary (73.4 %) and the highest rate of appropriate (26.6 %) FNB recommendation. For other RSSs, the rates of unnecessary and appropriate FNB were between 75.2 %-77.1 % and 22.9 %-24.8 %. The lowest rate of missed FNB (14.7 %) and the highest rate of avoided FNB (85.3 %) was found for ACR TI-RADS. For the other RSSs, the rates of missed and avoided FNB were between 17.8 %-26.9 % and 73.1 %-82.2 %. When the size cutoff was disregarded, an increase of correct recommendations and a decrease of incorrect recommendations was observed for all RSSs. CONCLUSION: The RSSs vary in their ability to correctly recommend for or against FNB. An understanding of the impact of nodule size cutoffs seems necessary for the future of TIRADS.

Diagnostic Performance of Kwak, EU, ACR, and Korean TIRADS as Well as ATA Guidelines for the Ultrasound Risk Stratification of Non-Autonomously Functioning Thyroid Nodules in a Region with Long History of Iodine Deficiency: A German Multicenter Trial.

Germany has a long history of insufficient iodine supply and thyroid nodules occur in over 30% of the adult population, the vast majority of which are benign. Non-invasive diagnostics remain challenging, and ultrasound-based risk stratification systems are essential for selecting lesions requiring further clarification. However, no recommendation can yet be made about which system performs the best for iodine deficiency areas. In a German multicenter approach, 1211 thyroid nodules from 849 consecutive patients with cytological or histopathological results were enrolled. Scintigraphically hyperfunctioning lesions were excluded. Ultrasound features were prospectively recorded, and the resulting classifications according to five risk stratification systems were retrospectively determined. Observations determined 1022 benign and 189 malignant lesions. The diagnostic accuracies were 0.79, 0.78, 0.70, 0.82, and 0.79 for Kwak Thyroid Imaging Reporting and Data System (Kwak-TIRADS), American College of Radiology (ACR) TI-RADS, European Thyroid Association (EU)-TIRADS, Korean-TIRADS, and American Thyroid Association (ATA) Guidelines, respectively. Receiver Operating Curves revealed Areas under the Curve of 0.803, 0.795, 0.800, 0.805, and 0.801, respectively. According to the ATA Guidelines, 135 thyroid nodules (11.1%) could not be classified. Kwak-TIRADS, ACR TI-RADS, and Korean-TIRADS outperformed EU-TIRADS and ATA Guidelines and therefore can be primarily recommended for non-autonomously functioning lesions in areas with a history of iodine deficiency.

Radiation and Brain Tumors: An Overview.

The use of radiation is an essential part of both modern cancer diagnostic assessment and treatment. Next-generation imaging devices create 3D visualizations, allowing for better diagnoses and improved planning of precision treatment. This is particularly important for primary brain cancers such as diffuse intrinsic pontine glioma or the most common primary brain tumor, glioblastoma, because radiotherapy is often the only treatment modality that offers a significant improvement in survival and quality of life. In this review, we give an overview of the different imaging techniques and the historic role of radiotherapy and its place in modern cancer therapy. Finally, we discuss three key areas of risks associated with the use of ionizing radiation: (1) brain tumor induction mainly as a consequence of the diagnostic use of radiation; (2) cognitive decline as a consequence of treating childhood brain tumors as an example of long term consequences often neglected in favor of highlighting secondary primary cancers; and (3) pro-proliferative and pro-invasive alterations that occur in tumor cells that survive radiotherapy. Throughout the discussion, we highlight areas of potential future research.

Combined PET/MRI improves diagnostic accuracy in patients with prostate cancer: a prospective diagnostic trial.

PURPOSE: The pretherapeutic assessment of prostate cancer is challenging and still holds the risk of over- or undertreatment. This prospective trial investigates positron emission tomography (PET) with [(18)F]fluoroethylcholine (FEC) combined with endorectal magnetic resonance imaging (MRI) for the assessment of primary prostate cancer. EXPERIMENTAL DESIGN: Patients with prostate cancer based on needle biopsy findings, scheduled for radical prostatectomy, were assessed by FEC-PET and MRI in identical positioning. After prostatectomy, imaging results were compared with histologic whole-mount sections, and the PET/MRI lesion-based semiquantitative FEC uptake was compared with biopsy Gleason scores and postoperative histology. RESULTS: PET/MRI showed a patient-based sensitivity of 95% (36/38; 95% confidence interval (CI), 82%-99%). The analysis of 128 prostate lesions demonstrated a sensitivity/specificity/positive predictive value/negative predictive value/accuracy of 67%/35%/59%/44%/54% (P = 0.8295) for MRI and 85%/45%/68%/69%/68% (P = 0.0021) for PET, which increased to 84%/80%/85%/78%/82% (P < 0.0001) by combined FEC-PET/MRI in lesions >5 mm (n = 98). For lesions in patients with Gleason >6 tumors (n = 43), MRI and PET achieved 73%/31%/71%/33%/60% (P = 1.0000) and 90%/62%/84%/73%/81% (P = 0.0010), which were improved to 87%/92%/96%/75%/88% (P < 0.0001) by combined PET/MRI. Applying semiquantitative PET analysis, carcinomas with Gleason scores >6 were distinguished from those with Gleason ≤ 6 with a specificity of 90% and a positive predictive value of 83% (P = 0.0011; needle biopsy 71%/60%, P = 0.1071). CONCLUSIONS: In a prospective diagnostic trial setting, combined FEC-PET/MRI achieved very high sensitivity in the detection of the dominant malignant lesion of the prostate, and markedly improved upon PET or MRI alone. Noninvasive Gleason score assessment was more precise than needle biopsy in this patient cohort. Hence, FEC-PET/MRI merits further investigation in trials of randomized, multiarm design.