OBJECTIVE:To evaluate the sensitivity of a stepwise preoperative imaging regimen for patients with primary hyperparathyroidism. STUDY DESIGN:Prospective cohort study. SETTING:A high-volume tertiary referral center for parathyroidectomy. METHODS:Patients with primary hyperparathyroidism referred for parathyroidectomy underwent surgeon-performed ultrasound as the primary preoperative imaging examination. The diagnostic confidence of the examiner on a scale from 0 to 3 determined whether additional imaging was acquired. If ultrasound identified an enlarged parathyroid gland with certainty (score 3), the patient was booked directly for surgery. If the confidence score was <3, the patient underwent either parathyroid scintigraphy or 18F-choline PET/CT. The gold standard was the intraoperative location of pathological parathyroid glands combined with biochemical cure ≥6 months after surgery. The primary endpoint was the sensitivity of the stepwise imaging regimen per patient, irrespective of the number of acquired imaging modalities. Secondary endpoints were the sensitivity per gland and the sensitivity of the imaging regimen if the cut-off for additional imaging had been a confidence score of 1 or 2. RESULTS:Upfront ultrasound spared 49 of 99 patients (49.5%) from additional imaging and correctly localized ≥1 pathological parathyroid gland in 98.0% of patients [95% CI 92.9-99.8]. The per-gland sensitivity was 92.5% [95% CI 84.8-1.0]. When changing the cut-off to a confidence score of 2, the per-patient sensitivity remained 98.0% [95% CI 92.9-99.8]. CONCLUSION:Our study demonstrates that a stepwise imaging regimen based on upfront ultrasound by an experienced examiner can substantially reduce the number of radiation-based supplemental scans, while maintaining a high sensitivity.

PURPOSE:The preferred nuclear medicine method for identification of hyperfunctioning parathyroid glands in hyperparathyroidism (HPT) develops continuously in relation to the technological progress. Diagnostic methods based on PET/CT have during recent years evolved with new tracer possibilities competing with traditional scintigraphic methods. This investigation is a head-to-head comparison of Tc-99m-sestamibi SPECT/CT gamma camera scintigraphy (sestamibi SPECT/CT) and C-11-L-methionin PET/CT imaging (methionine PET/CT) for preoperative identification of hyperfunctioning parathyroid glands.PROCEDURES:The study is a prospective cohort study including 27 patients diagnosed with primary hyperparathyroidism (PHPT). Two nuclear medicine physicians assessed all examinations independently and blinded. All scanning assessments were matched to the final surgical diagnosis as confirmed by histopathology. Biochemical monitoring of the therapeutical effects was performed preoperatively by PTH-measurements and followed postoperatively for up to 12 months. Comparisons were made for differences in sensitivity and positive predictive value (PPV).RESULTS:Twenty-seven patients (18 females, 9 males; mean age (range): 58.9 years (34.1-79)) were enrolled into the study. The 27 patients had a total of 33 identified sites of lesions of which 28 (85%) turned out to be histopathological verified hyperfunctioning parathyroid glands. The sensitivity and PPV for sestamibi SPECT/CT were 0.71 and 0.95; that of methionine PET/CT was 0.82 and 1, respectively. Both sensitivity and PPV were slightly lower for sestamibi SPECT/CT than for methionine PET PET/CT (-0.11, 95% confidence interval (95% CI): -0.29 to 0.08; -0.05, 95% CI: -0.14 to 0.04, respectively), but not to a statistically significant extent (p=0.38 and p=0.31). The sensitivity and PPV for diagnostic CT were 0.64 (95% CI: 0.44 to 0.81) and 1 (95% CI: 0.81 to 1).CONCLUSIONS:Methionine PET/CT performed comparable to sestamibi SPECT/CT with respect to identification and localization of hyperfunctioning parathyroid glands prior to surgery.

Importance:Scintigraphy and ultrasonography are common imaging modalities for the preoperative localization of enlarged parathyroid glands in primary hyperparathyroidism. When comparing the 2 modalities, the benefits of ultrasonography in terms of convenience, patient comfort, duration, cost, and lack of radiation should be taken into account. Objective:To investigate whether surgeon-performed ultrasonography, with or without contrast-enhanced ultrasonography (CEUS), is noninferior to scintigraphy for localizing pathological parathyroid glands in patients with primary hyperparathyroidism. Design, Setting, and Participants:Prospective, paired, noninferiority cohort study performed at a high-volume tertiary referral center for parathyroidectomy with blinded examiners and a 6-month follow-up. Participants were adults (age ≥18 years) referred for parathyroidectomy due to primary hyperparathyroidism. Of 207 eligible patients, 35 were excluded, leaving 172 enrolled in the study. Inclusion lasted from September 2019 until February 2021. Follow-up ended in December 2021. Exposures:99mTechnetium-pertechnetate/99mtechnetium-sestamibi subtraction scintigraphy with 99mtechnetium-sestamibi single-photon emission computed tomography/computed tomography, followed by surgeon-performed ultrasonography and CEUS. Main Outcomes and Measures:The sensitivity of each imaging modality in localizing pathological parathyroid glands, calculated on a per-quadrant and a per-patient basis, respectively. The a priori noninferiority margin was a lower 95% confidence limit for the difference in sensitivity not falling below -10%. Results:Out of 172 participants, 139 (80.8%) were women, the median (range) age was 65 (24-87) years, and the median (IQR) follow-up was 200.5 (181-280.25) days. Quadrant sensitivity (95% CI) was 70.9% (63.2%-78.5%) for ultrasonography, 68.4% (60.4%-76.5%) for ultrasonography plus CEUS, and 67.0% (60.0%-74.0%) for scintigraphy. The sensitivity difference (95% CI) compared with scintigraphy was 3.9% (-4.1% to 11.8%) for ultrasonography and 1.5% (-6.4% to 9.3%) for ultrasonography plus CEUS, establishing noninferiority for both modalities. Per-patient sensitivity was 81.4% (74.8%-86.9%) for ultrasonography and 79.1% (72.2%-84.9%) for both scintigraphy and ultrasonography plus CEUS. The sensitivity difference compared with scintigraphy was 2.3% (-6.8% to 11.4%) for ultrasonography and 0.0% (-9.1% to 9.1%) for ultrasonography plus CEUS, establishing noninferiority for both modalities. Conclusions and Relevance:In this cohort study, conventional ultrasonography by an experienced parathyroid surgeon-sonographer was noninferior to scintigraphy and may constitute a valid first-line imaging modality in patients with primary hyperparathyroidism, even without the addition of CEUS. Further imaging should be reserved for cases that are equivocal or nonlocalizing on ultrasonography.

Amyloidosis is a severe disease caused by protein misfolding and deposition in tissues and organs. Thirty-eight different proteins are known to be amyloidogenic. Amyloidosis is categorized into inherited or acquired, and systemic or localized. Light-chain (AL)- and transthyretin (ATTR) amyloidosis are the two most common subtypes. Awareness, early diagnosis, accurate subtyping and relevant treatment are crucial for the management. Novel therapies of systemic AL and ATTR amyloidosis have considerably improved outcome and survival. The aim of this review is to increase awareness and knowledge on diagnosing amyloidosis.

The use of 18F-Fluoro-D-deoxy-glucose -positron emission tomography/computed tomography (FDG-PET/CT) in gastrointestinal (GI)-malignancies may not be as straightforward as in many other cancers, but the potential is clearly there in select clinical settings. The challenges include the relative non-specificity of FDG, the variable degrees of physiologic FDG-uptake, and the heterogeneous FDG-uptake in different cell types within the GI-domain, which all together hamper the use in primary diagnostics. In general, the literature is older, heterogeneous, and based on stand-alone PET, which is now largely considered obsolete. There is emerging evidence for use of hybrid PET/CT, but the literature is still relatively sparse. The main indications are preoperative staging of distant metastases, not only in limited disease but also before curative treatment of limited metastatic disease. Controversies remain concerning liver metastases but improved technology boast well for the future role of FDG-PET/CT not least concerning equivocal findings on conventional imaging. In our opinion, an important upcoming indication is early response assessment, perhaps mostly in the neoadjuvant settings of upper GI-malignancies, but standardization of response assessment criteria is lacking before a more widespread implementation is feasible. Finally, there seems to be a significant role in recurrence detection, especially in CRC.