The accuracy and intra- and interobserver variability of PSMA PET/CT for the local staging of primary prostate cancer

PURPOSE

Prostate-specific membrane antigen (PSMA) positron emission tomography/ computed tomography (PET/CT) is recognized as the most accurate imaging modality for detection of metastatic high-risk prostate cancer (PCa). Its role in the local staging of disease is yet unclear. We assessed the intra- and interobserver variability, as well as the diagnostic accuracy of the PSMA PET/CT based molecular imaging local tumour stage (miT-stage) for the local tumour stage assessment in a large, multicentre cohort of patients with intermediate and high-risk primary PCa, with the radical prostatectomy specimen (pT-stage) serving as the reference standard.

METHODS

A total of 600 patients who underwent staging PSMA PET/CT before robot-assisted radical prostatectomy was studied. In 579 PSMA positive primary prostate tumours a comparison was made between miT-stage as assessed by four nuclear physicians and the pT-stage according to ISUP protocol. Sensitivity, specificity and diagnostic accuracy were determined. In a representative subset of 100 patients, the intra-and interobserver variability were assessed using Kappa-estimates.

RESULTS

The sensitivity and specificity of the PSMA PET/CT based miT-stage were 58% and 59% for pT3a-stage, 30% and 97% for ≥ pT3b-stage, and 68% and 61% for overall ≥ pT3-stage, respectively. No statistically significant differences in diagnostic accuracy were found between tracers. We found a substantial intra-observer agreement for PSMA PET/CT assessment of ≥ T3-stage (k 0.70) and ≥ T3b-stage (k 0.75), whereas the interobserver agreement for the assessment of ≥ T3-stage (k 0.47) and ≥ T3b-stage (k 0.41) were moderate.

CONCLUSION

In a large, multicentre study evaluating 600 patients with newly diagnosed intermediate and high-risk PCa, we showed that PSMA PET/CT may have a value in local tumour staging when pathological tumour stage in the radical prostatectomy specimen was used as the reference standard. The intra-observer and interobserver variability of assessment of tumour extent on PSMA PET/CT was moderate to substantial.

A Systematic Review on the Diagnostic Value of Fibroblast Activation Protein Inhibitor PET/CT in Genitourinary Cancers

In contemporary oncologic diagnostics, molecular imaging modalities are pivotal for precise local and metastatic staging. Recent studies identified fibroblast activation protein as a promising target for molecular imaging across various malignancies. Therefore, we aimed to systematically evaluate the current literature on the utility of fibroblast activation protein inhibitor (FAPI) PET/CT for staging patients with genitourinary malignancies. Methods: A systematic Embase and Medline search was conducted, according to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) process, on August 1, 2023. Relevant publications reporting on the diagnostic value of FAPI PET/CT in genitourinary malignancies were identified and included. Studies were critically reviewed using a modified version of a tool for quality appraisal of case reports. Study results were summarized using a narrative approach. Results: We included 22 retrospective studies with a cumulative total of 69 patients, focusing on prostate cancer, urothelial carcinoma of the bladder and of the upper urinary tract, renal cell carcinoma, and testicular cancer. FAPI PET/CT was able to visualize both local and metastatic disease, including challenging cases such as prostate-specific membrane antigen (PSMA)-negative prostate cancer. Compared with radiolabeled 18F-FDG and PSMA PET/CT, FAPI PET/CT showed heterogeneous performance. In selected cases, FAPI PET/CT demonstrated superior tumor visualization (i.e., better tumor-to-background ratios and visualization of small tumors or metastatic deposits visible in no other way) over 18F-FDG PET/CT in detecting local or metastatic disease, whereas comparisons with PSMA PET/CT showed both superior and inferior performances. Challenges in FAPI PET/CT arise from physiologic urinary excretion of most FAPI radiotracers, hindering primary-lesion visualization in the bladder and upper urinary tract, despite generally providing high tumor-to-background ratios. Conclusion: The current findings suggest that FAPI PET/CT may hold promise as a future tool to aid clinicians in detecting genitourinary malignancies. Given the substantial heterogeneity among the included studies and the limited number of patients, caution in interpreting these findings is warranted. Subsequent prospective and comparative investigations are anticipated to delve more deeply into this innovative imaging modality and elucidate its role in clinical practice.

Optimization and validation of 18F-DCFPyL PET radiomics-based machine learning models in intermediate- to high-risk primary prostate cancer

INTRODUCTION

Radiomics extracted from prostate-specific membrane antigen (PSMA)-PET modeled with machine learning (ML) may be used for prediction of disease risk. However, validation of previously proposed approaches is lacking. We aimed to optimize and validate ML models based on 18F-DCFPyL-PET radiomics for the prediction of lymph-node involvement (LNI), extracapsular extension (ECE), and postoperative Gleason score (GS) in primary prostate cancer (PCa) patients.

METHODS

Patients with intermediate- to high-risk PCa who underwent 18F-DCFPyL-PET/CT before radical prostatectomy with pelvic lymph-node dissection were evaluated. The training dataset included 72 patients, the internal validation dataset 24 patients, and the external validation dataset 27 patients. PSMA-avid intra-prostatic lesions were delineated semi-automatically on PET and 480 radiomics features were extracted. Conventional PET-metrics were derived for comparative analysis. Segmentation, preprocessing, and ML methods were optimized in repeated 5-fold cross-validation (CV) on the training dataset. The trained models were tested on the combined validation dataset. Combat harmonization was applied to external radiomics data. Model performance was assessed using the receiver-operating-characteristics curve (AUC).

RESULTS

The CV-AUCs in the training dataset were 0.88, 0.79 and 0.84 for LNI, ECE, and GS, respectively. In the combined validation dataset, the ML models could significantly predict GS with an AUC of 0.78 (p<0.05). However, validation AUCs for LNI and ECE prediction were not significant (0.57 and 0.63, respectively). Conventional PET metrics-based models had comparable AUCs for LNI (0.59, p>0.05) and ECE (0.66, p>0.05), but a lower AUC for GS (0.73, p<0.05). In general, Combat harmonization improved external validation AUCs (-0.03 to +0.18).

CONCLUSION

In internal and external validation, 18F-DCFPyL-PET radiomics-based ML models predicted high postoperative GS but not LNI or ECE in intermediate- to high-risk PCa. Therefore, the clinical benefit seems to be limited. These results underline the need for external and/or multicenter validation of PET radiomics-based ML model analyses to assess their generalizability.

Staging fluorodeoxyglucose positron emission tomography/computed tomography for muscle-invasive bladder cancer: a nationwide population-based study

OBJECTIVE

To provide insight into the use and staging information on lymph-node involvement added by fluorodeoxyglucose-positron emission tomography/computed tomography (FDG-PET/CT) in patients with muscle-invasive bladder cancer (MIBC), based on a nationwide population-based cohort study.

PATIENTS AND METHODS

We analysed a nationwide cohort of patients with MIBC without signs of distant metastases, newly diagnosed in the Netherlands between November 2017 and October 2019. From this cohort, we selected patients who underwent pre-treatment staging with CT only or CT and FDG-PET/CT. The distribution of patients, disease characteristics, imaging findings, nodal status (clinical nodal stage cN0 vs cN+) and treatment were described for each imaging modality group (CT only vs CT and FDG-PET/CT).

RESULTS

We identified 2731 patients with MIBC: 1888 (69.1%) underwent CT only; 606 (22.2%) underwent CT and FDG-PET/CT, 237 (8.6%) underwent no CT. Of the patients who underwent CT only, 200/1888 (10.6%) were staged as cN+, vs 217/606 (35.8%) who underwent CT and FDG-PET/CT. Stratified analysis showed that this difference was found in patients with clinical tumour stage (cT)2 as well as cT3/4 MIBC. Of patients who underwent both imaging modalities and were staged with CT as cN0, 109/498 (21.9%) were upstaged to cN+ based on FDG-PET/CT. Radical cystectomy (RC) was the most common treatment within both imaging groups. Preoperative chemotherapy was more frequently applied in cN+ disease and in FDG-PET/CT-staged patients. Concordance of pathological N stage after upfront RC was higher among patients staged as cN+ with CT and FDG-PET/CT (50.0% pN+) than those staged as cN+ with only CT (39.3%).

CONCLUSION

Patients with MIBC who underwent pre-treatment staging with FDG-PET/CT were more often staged as lymph node positive, regardless of cT stage. In patients with MIBC who underwent CT and FDG-PET/CT, FDG-PET/CT led to clinical nodal upstaging in approximately one-fifth. Additional imaging findings may influence subsequent treatment strategies.

The Diagnostic Value of PSMA PET/CT in Men with Newly Diagnosed Unfavorable Intermediate-Risk Prostate Cancer

Our objective was to determine the diagnostic value of prostate-specific membrane antigen (PSMA) PET/CT in staging men with newly diagnosed unfavorable intermediate-risk prostate cancer (PCa). Methods: Patients with newly diagnosed unfavorable intermediate-risk PCa, in whom PSMA PET/CT was performed as a primary staging modality, were retrospectively studied. PSMA PET/CT was performed at several diagnostic centers and reported by expert nuclear medicine physicians within 2 high-volume PCa centers. A multivariate logistic regression analysis, taking into account clinical, biochemical, pathologic, and radiologic variables, was performed to identify potential independent predictors for metastatic disease on PSMA PET/CT. Results: In total, 396 men with newly diagnosed unfavorable intermediate-risk PCa were studied. Metastatic disease was observed in 37 (9.3%) men, of whom 29 (7.3%) had molecular imaging locoregional lymph node metastases (miN1) and 16 (4.0%) had distant metastases (miM1). A radiologic tumor stage of at least T3 on MRI (odds ratio, 2.72 [95% CI, 1.27-5.83]; P = 0.01) and more than 50% positive prostate biopsies (odds ratio, 3.87 [95% CI, 1.74-8.62]; P = 0.001) were found to be independently associated with metastatic disease on PSMA PET/CT. Conclusion: Given that metastatic disease was observed in nearly 1 in 10 men with newly diagnosed unfavorable intermediate-risk PCa, PSMA PET/CT is considered to be of diagnostic value within this population. Further stratification using the radiologic tumor stage and the percentage of positive prostate biopsies could aid in identifying those patients at risk of having metastatic disease on PSMA PET/CT.

Incidence of PSMA PET thyroid incidentaloma depends on analysis method and tracer

OBJECTIVE

To investigate the incidences of prostate-specific membrane antigen (PSMA) thyroid incidentaloma (PTI) using different methods to define PTI, to compare the incidence of PTI among different PSMA PET tracers, and to evaluate the clinical consequences of PTI.

METHODS

PSMA PET/CT scans in consecutive patients with primary prostate cancer were analyzed for the presence of PTI using a structured visual (SV) analysis reporting any elevated thyroidal uptake; a semi-quantitative (SQ) analysis using a SUVmax thyroid/bloodpool (t/b) ratio ≥ 2.0 as cutoff; and an analysis of PTI incidence in the clinical reports (RV analysis).

RESULTS

A total of 502 patients were included. The incidence of PTIs was 22% in the SV analysis, 7% in the SQ analysis, and 2% in the RV analysis. PTI incidences differed significantly from 29 to 64% (SQ, resp. SV analysis) for [¹⁸F]PSMA-1007, 7 to 23% for [⁶⁸Ga]PSMA-11, 2 to 8% for [¹⁸F]DCFPyL, and to 0% for [¹⁸F]PSMA-JK-7. The majority of PTI in the SV and SQ analyses consisted of diffuse (72-83%) and/or only slightly elevated thyroidal uptake (70%). Inter-observer agreement in the SV analysis was substantial (kappa = 0.76-0.78). During follow-up (median 16.8 months), there were no thyroid-related adverse events except in three patients.

CONCLUSIONS

The incidence of PTI varies greatly among different PSMA PET tracers and is strongly dependent on the analysis method applied. PTI may safely be restricted to focal thyroidal uptake with a SUVmax t/b ratio ≥ 2.0. The clinical pursuit of a PTI must be weighed up to the expected outcome of the underlying disease.

KEY POINTS

• Thyroid incidentalomas (PTIs) are recognized in PSMA PET/CT. • Incidence of PTI varies greatly among PET tracers and analysis methods. • Incidence of thyroid-related adverse events in PTI cases is low.

Genetic Aspects and Molecular Testing in Prostate Cancer: A Report from a Dutch Multidisciplinary Consensus Meeting

Background

Germline and tumour genetic testing in prostate cancer (PCa) is becoming more broadly accepted, but testing indications and clinical consequences for carriers in each disease stage are not yet well defined.

Objective

To determine the consensus of a Dutch multidisciplinary expert panel on the indication and application of germline and tumour genetic testing in PCa.

Design setting and participants

The panel consisted of 39 specialists involved in PCa management. We used a modified Delphi method consisting of two voting rounds and a virtual consensus meeting.

Outcome measurements and statistical analysis

Consensus was reached if ≥75% of the panellists chose the same option. Appropriateness was assessed by the RAND/UCLA appropriateness method.

Results and limitations

Of the multiple-choice questions, 44% reached consensus. For men without PCa having a relevant family history (familial PCa/BRCA-related hereditary cancer), follow-up by prostate-specific antigen was considered appropriate. For patients with low-risk localised PCa and a family history of PCa, active surveillance was considered appropriate, except in case of the patient being a BRCA2 germline pathogenic variant carrier. Germline and tumour genetic testing should not be done for nonmetastatic hormone-sensitive PCa in the absence of a relevant family history of cancer. Tumour genetic testing was deemed most appropriate for the identification of actionable variants, with uncertainty for germline testing. For tumour genetic testing in metastatic castration-resistant PCa, consensus was not reached for the timing and panel composition. The principal limitations are as follows: (1) a number of topics discussed lack scientific evidence, and therefore the recommendations are partly opinion based, and (2) there was a small number of experts per discipline.

Conclusions

The outcomes of this Dutch consensus meeting may provide further guidance on genetic counselling and molecular testing related to PCa.

Patient summary

A group of Dutch specialists discussed the use of germline and tumour genetic testing in prostate cancer (PCa) patients, indication of these tests (which patients and when), and impact of these tests on the management and treatment of PCa.

Added Clinical Value of 18F-FDG-PET/CT to Stage Patients With High-Risk Non-Muscle Invasive Bladder Cancer Before Radical Cystectomy

INTRODUCTION AND OBJECTIVES

18F-fluorodeoxyglucose positron-emission tomography-computed tomography (FDG-PET/CT) is increasingly used in the preoperative staging of patients with muscle-invasive bladder cancer. The clinical added value of FDG-PET/CT in high-risk non-muscle invasive bladder cancer (NMIBC) is unknown. In this study, the value of FDG-PET/CT in addition to contrast enhanced (CE)-CT was evaluated in high-risk NMIBC before radical cystectomy (RC).

MATERIALS AND METHODS

This is a retrospective analysis of consecutive patients with high risk and very-high risk urothelial NMIBC scheduled for RC in a tertiary referral center between 2011 and 2020. Patients underwent staging with CE-CT (chest and abdomen/pelvis) and FDG-PET/CT. We assessed the clinical disease stage before and after FDG-PET/CT and the treatment recommendation based on the stage before and after FDG-PET/CT. The accuracy of CT and FDG-PET/CT for identifying metastatic disease was defined by the receiver-operating curve using a reference-standard including histopathology/cytology (if available), imaging and follow-up.

RESULTS

A total of 92 patients were identified (median age: 71 years). In 14/92 (15%) patients, FDG-PET/CT detected metastasis (12 suspicious lymph nodes and 4 distant metastases). The disease stage changed in 11/92 (12%) patients based on additional FDG-PET/CT findings. FDG-PET/CT led to a different treatment in 9/92 (10%) patients. According to the reference standard, 25/92 (27%) patients had metastases. The sensitivity, specificity and accuracy of FDG-PET/CT was 36%, 93% and 77% respectively, versus 12%, 97% and 74% of CE-CT only. The area under the ROC curve was 0.643 for FDG-PET/CT and 0.545 for CT, P = .036.

CONCLUSION

The addition of FDG-PET/CT to CE-CT imaging changed the treatment in 10% of patients and proved to be a valuable diagnostic tool in a selected subgroup of NMIBC patients scheduled for RC.

Early response evaluation of PD-1 blockade in NSCLC patients through FDG-PET-CT and T cell profiling of tumor-draining lymph nodes

Better biomarkers for programmed death - (ligand) 1 (PD-(L)1) checkpoint blockade in non-small cell lung cancer (NSCLC) are needed. We explored the predictive value of early response evaluation using Fluor-18-deoxyglucose positron emission tomography and pre- and on-treatment flowcytometric T-cell profiling in peripheral blood and tumor-draining lymph nodes (TDLN). The on-treatment evaluation was performed 7-14 days after the start of PD-1 blockade in NSCLC patients. These data were related to (pathological) tumor response, progression-free survival, and overall survival (OS). We found that increases in total lesion glycolysis (TLG) had a strong reverse correlation with OS (r = -0.93, p = 0.022). Additionally, responders showed decreased progressors and increased Treg frequencies on-treatment. Frequencies of detectable PD-1-expressing CD8⁺ T cells decreased in responders but remained stable in progressors. This was especially found in the TDLN. Changes in activated Treg rates in TDLN were strongly but, due to low numbers of data points, non-significantly correlated with ΔTLG and reversely correlated with OS.

Incidental Findings on 18F-Fluorocholine PET/CT for Parathyroid Imaging

Introduction   ¹⁸ F-choline positron emission tomography/computed tomography (PET/CT) is an upcoming imaging technique for the localization of hyperfunctioning parathyroid glands. However, ¹⁸ F-choline is a nonspecific tracer that also accumulates in malignancies, inflammatory lesions, and several other benign abnormalities. The aim of this study was to determine the occurrence and relevance of incidental findings on ¹⁸ F-choline PET/CT for parathyroid localization.

Materials and Methods   ¹⁸ F-choline PET/CTs performed in our center for parathyroid localization from 2015 to 2019 were reviewed. Abnormal uptake of ¹⁸ F-choline, with or without anatomical substrate on the co-registered low-dose CT and also incidental findings on CT without increased ¹⁸ F-choline uptake were recorded. Each finding was correlated with follow-up data from the electronic medical records.

Results  A total of 388 ¹⁸ F-choline PET/CTs were reviewed, with 247 incidental findings detected in 226 patients (58%): 82 ¹⁸ F-choline positive findings with corresponding pathology on CT, 16 without CT substrate, and 149 ¹⁸ F-choline negative abnormalities on CT. Malignant lesions were detected in 10/388 patients (2.6%). Of all 98 detected ¹⁸ F-choline positive lesions, 15 were malignant (15.3%), concerning 4 metastases and 11 primary malignancies: breast carcinoma ( n  = 7), lung carcinoma ( n  = 2), thyroid carcinoma ( n  = 1), and skin melanoma ( n  = 1).

Conclusion  Clinically relevant incidental findings were observed in a substantial number of patients. In 15.3% of the incidental ¹⁸ F-choline positive findings, the lesions were malignant. These data contribute to better knowledge of ¹⁸ F-choline distribution, enhance interpretation of ¹⁸ F-choline PET/CT, and guide follow-up of incidental findings. Attention should especially be paid to breast lesions in this particular patient group with hyperparathyroidism in which women are typically over-represented.

Reproducibility of PSMA PET/CT Imaging for primary staging of treatment-naïve prostate cancer patients depends on the applied radiotracer: a retrospective study

Purpose: To determine and compare the interobserver variability of three clinically frequently used radiotracers targeting the prostate specific membrane antigen (PSMA), namely ¹⁸F-DCFPyL, ¹⁸F-PSMA-1007 and ⁶⁸Ga-PSMA-11, in primary prostate cancer (PCa) staging. Methods: Patients with newly diagnosed PCa in whom a PSMA-PET/CT was performed for primary staging purposes, were retrospectively included. All PSMA-PET/CT images were centrally overread within a high-volume PCa center and original reports (from referring hospitals) were compared to overread reports (from the overreading hospital). To assess the interobserver variability a Cohen's kappa analysis was used. To study possible differences in interobserver variability between the three used PSMA-radiotracers, multivariate logistic regression analyses were used. Results: In total, 584 patients with newly diagnosed PCa were included in the analysis. ¹⁸F-DCFPyL, ¹⁸F-PSMA-1007 and ⁶⁸Ga-PSMA-11 were undertaken in 205/584 (35.1%), 168/584 (28.8%) and 211/584 (36.1%) patients, respectively. The overall agreement (Cohen's kappa analysis) for locoregional lymph-node metastases, distant lymph-node metastases, bone metastases and visceral metastases was 0.86, 0.86, 0.80 and 0.46, respectively. ¹⁸F-PSMA-1007 showed a significantly higher interobserver variability regarding bone metastases, compared to ¹⁸F-DCFPyL and ⁶⁸Ga-PSMA-11 (P = 0.001 and P = 0.03, respectively). Additionally, ¹⁸F-PSMA-1007 showed a significantly higher interobserver variability regarding overall agreement and locoregional lymph-node metastases, compared to ¹⁸F-DCFPyL (p<0.001 and P = 0.01, respectively). Conclusion: The interobserver variability differs among the three clinically frequently used PSMA-radiotracers (¹⁸F-DCFPyL, ¹⁸F-PSMA-1007 and ⁶⁸Ga-PSMA-11) in patients with newly diagnosed PCa. The agreement in bone metastases is significantly worse for ¹⁸F-PSMA-1007, mainly due to non-specific tracer uptake in osseous structures. Based on our findings, PSMA-PET/CT scans undertaken with ¹⁸F-PSMA-1007 in primary staging should be interpreted carefully and training in interpreting this specific PSMA-radiotracer is strongly advised.

Effects of furosemide and tracer selection on urinary activity and peri-bladder artefacts in PSMA PET/CT: a single-centre retrospective study

BACKGROUND

High urinary activity in urinary bladder and ureters may hamper interpretation of prostate cancer and regional nodal metastases in prostate-specific membrane antigen (PSMA) PET/CT. The goal of this study was to assess effects of furosemide and choice of tracer on urinary activity in the bladder and ureters, as well as on occurrence of peri-bladder artefacts in PET/CT.

METHODS

Four cohorts with a total of 202 men staged with PSMA PET/CT for prostate cancer received either ⁶⁸Ga-PSMA-11 as tracer, with (cohort G+) or without 10mg intravenous furosemide (G-) concurrent with tracer, or ¹⁸F-DCFPyL with (F+) or without furosemide (F-). SUVmax of bladder and ureters, presence, type, and severity of peri-bladder artefacts were compared between cohorts. The influence of furosemide and choice of tracer was determined while taking differences in biodistribution time into account.

RESULTS

Median SUVmax bladder was 43,5; 14,8; 61,7 and 22,8 in cohorts G-, G+, F- and F+, respectively, resulting in significant overall (p < 0.001) and between cohort differences (p adjusted < 0.001 to 0.003) except between G- and F+. Median SUVmax ureter was 6.4; 4.5; 8.1 and 6.0 in cohorts G-, G+, F- and F+, respectively, resulting in significant overall (p < 0.001) and between cohort differences for G+ : F- and F- : F+ (p < 0.001, respectively, 0.019). Significant effects of furosemide and choice of tracer on SUVmax bladder (p < 0.001 resp. p = 0.001) and of furosemide on SUVmax ureter (p < 0.001) were found, whereas differences in biodistribution time had not impacted these results significantly. Peri-bladder artefacts were present in 42/202 (21%) patients and were significantly more frequent in the F- cohort, respectively, less frequent in the G+ cohort (p = 0.001 resp. p < 0.001). Peri-bladder artefacts had a direct positive correlation with SUVmax bladder (p = 0.033).

CONCLUSIONS

Increased urinary activity and higher incidence of peri-bladder artefacts were found in ¹⁸F-DCFPyL compared to ⁶⁸Ga-PSMA-11 PET/CT. Effective reduction of urinary activity may be reached through forced diuresis using 10mg intravenous furosemide, which is especially advantageous in ¹⁸F-DCFPyL PET/CT.

18F-FDG PET/CT During Neoadjuvant Targeted Therapy in Prior Unresectable Stage III Melanoma Patients: Can (Early) Metabolic Imaging Predict Histopathologic Response or Recurrence?

PURPOSE

The aim of this study was to investigate whether 18F-FDG PET/CT can predict histopathological response or recurrence in BRAF-mutated unresectable locally advanced stage III melanoma treated with neoadjuvant BRAF/MEK inhibition followed by resection and the value of PET in detecting early recurrence after resection.

PATIENTS AND METHODS

Twenty BRAF-mutated, unresectable stage III melanoma patients received BRAF/MEK inhibitors before surgery. 18F-FDG PET/CT was performed at baseline and 2 and 8 weeks after initiation of therapy. After resection, PET/CT was performed at specific time points during 5 years of follow-up. Pathological response was assessed on the dissection specimen. Response monitoring was measured with SUVmax, SUVpeak, MATV, and TLG and according to EORTC and PERCIST criteria.

RESULTS

Pathological response was assessed in 18 patients. Nine patients (50%) had a pathologic complete or near-complete response, and 9 (50%) had a pathologic partial or no response. EORTC or PERCIST response measurements did not correspond with pathologic outcome. SUVmax, SUVpeak, MATV, and TLG at all time points and absolute or percentage change among the 3 initial time points did not differ between the groups.During follow-up, 8 of 17 patients with R0 resection developed a recurrence, 6 recurrences were detected with imaging only, 4 of which with PET/CT in less than 6 months after surgery. PET parameters before surgery did not predict recurrence.

CONCLUSIONS

Baseline 18F-FDG PET or PET response in previous unresectable stage III melanoma patients seems not useful to predict pathologic response after neoadjuvant BRAF/MEK inhibitors treatment. However, PET/CT seems valuable in detecting recurrence early after R0 resection.

Löfgren Syndrome on 18F-FDG PET/CT: An Acute Manifestation of Sarcoidosis

ABSTRACT

A 58-year-old man presented with fever, erythema nodosum, and arthralgia of knee and ankle joints. Laboratory data showed signs of inflammation, and chest x-ray revealed bilateral hilar lymphadenopathy. 18F-FDG PET/CT was acquired to analyze the underlying causes and revealed FDG accumulation in thoracic lymphadenopathy and in subcutaneous lesions and periarticular uptake. This typical triad is known as Löfgren syndrome, an acute manifestation of sarcoidosis and which, as this case shows, can be visualized on 18F-FDG PET/CT. It is important to recognize this syndrome and to discriminate it from the classic presentation of sarcoidosis because of its different diagnostic and therapeutic consequences.

Pelvic lymph-node staging with 18F-DCFPyL PET/CT prior to extended pelvic lymph-node dissection in primary prostate cancer - the SALT trial

PURPOSE

The detection of lymph-node metastases (N1) with conventional imaging such as magnetic resonance imaging (MRI) and computed tomography (CT) is inadequate for primarily diagnosed prostate cancer (PCa). Prostate-specific membrane antigen (PSMA) PET/CT is successfully introduced for the staging of (biochemically) recurrent PCa. Besides the frequently used 68gallium-labelled PSMA tracers, 18fluorine-labelled PSMA tracers are available. This study examined the diagnostic accuracy of 18F-DCFPyL (PSMA) PET/CT for lymph-node staging in primary PCa.

METHODS

This was a prospective, multicentre cohort study. Patients with primary PCa underwent 18F-DCFPyL PET/CT prior to robot-assisted radical prostatectomy (RARP) with extended pelvic lymph-node dissection (ePLND). Patients were included between October 2017 and January 2020. A Memorial Sloan Kettering Cancer Centre (MSKCC) nomogram risk probability of ≥ 8% of lymph-node metastases was set to perform ePLND. All images were reviewed by two experienced nuclear physicians, and were compared with post-operative histopathologic results.

RESULTS

A total of 117 patients was analysed. Lymph-node metastases (N1) were histologically diagnosed in 17/117 patients (14.5%). The sensitivity, specificity, positive predictive value and negative predictive value for the 18F-DCFPyL PET/CT detection of pelvic lymph-node metastases on a patient level were 41.2% (confidence interval (CI): 19.4-66.5%), 94.0% (CI 86.9-97.5%), 53.8% (CI 26.1-79.6%) and 90.4% (CI 82.6-95.0%), respectively.

CONCLUSION

18F-DCFPyL PET/CT showed a high specificity (94.4%), yet a limited sensitivity (41.2%) for the detection of pelvic lymph-node metastases in primary PCa. This implies that current PSMA PET/CT imaging cannot replace diagnostic ePLND. Further research is necessary to define the exact place of PSMA PET/CT imaging in the primary staging of PCa.

"Skull on Fire": Monostotic Paget Disease of the Skull Bone

An 81-year-old woman was evaluated for a stroke. CT showed no intracranial abnormalities but diffuse patchy aspect of the neurocranium. An MRI and F-NA PET/CT were performed to differentiate between metastases, Paget disease, hyperostosis frontalis interna, and primary malignancy. MRI yielded no additional findings. F-NA PET/CT showed diffusely increased uptake in the skull and 4 spots with intense uptake. No other suspicious skeletal foci were seen elsewhere. Low-dose CT showed no sign of malignancy elsewhere. Image findings together with elevated serum alkaline phosphatase levels, slightly increased calcium levels, and normal phosphorus levels were interpreted as pathognomic for monostotic Paget.

Clinical verification of 18F-DCFPyL PET-detected lesions in patients with biochemically recurrent prostate cancer

Purpose

Radiolabeled Prostate-Specific Membrane Antigen (PSMA) PET/CT is the current standard-of-care for lesion detection in patients with biochemically recurrent (BCR) prostate cancer (PCa). However, rigorous verification of detected lesions is not always performed in routine clinical practice. To aid future ¹⁸F-radiolabeled PSMA PET/CT interpretation, we aimed to identify clinical/imaging characteristics that increase the likelihood that a PSMA-avid lesion is malignant.

Materials and methods

262 patients with BCR, who underwent ¹⁸F-DCFPyL PSMA PET/CT, were retrospectively analyzed. The malignant nature of ¹⁸F-DCFPyL PET-detected lesions was verified through any of the following metrics: (1) positive histopathological examination; (2) additional positive imaging; (3) a ≥50% decrease in Prostate-Specific Antigen (PSA) following irradiation of the lesion(s).

Results

In 226/262 PET scans (86.3%) at least one lesion suspicious for recurrent PCa was detected (‘positive scan’). In 84/226 positive scans (37.2%), at least one independent verification metric was available. PSMA PET-detected lesions were most often confirmed to be malignant (PCa) in the presence of a CT-substrate (96.5% vs. 55.6% without CT-substrate), with SUV_peak ≥3.5 (91.4% vs. 60.0% with SUV_peak<3.5), in patients with a PSA-level ≥2.0 ng/mL (83.7% vs. 65.7% in patients with PSA <2.0ng/mL) and in patients with >2 PET-positive lesions (94.1% vs. 64.2% in patients with 1–2 PET-positive lesions; p<0.001–0.03).

Conclusions

In this study, the clinical verification of ¹⁸F-DCFPyL PET-positive lesions in patients with BCR was performed. Diagnostic certainty of PET-detected lesions increases in the presence of characteristic abnormalities on CT, when SUV_peak is ≥3.5, when PSA-levels exceed 2.0 ng/mL or in patients with more than two PET-positive lesions.

18F-DCFPyL PET/CT for primary staging in 160 high-risk prostate cancer patients; metastasis detection rate, influence on clinical management and preliminary results of treatment efficacy

PURPOSE

Prostate-specific membrane antigen (PSMA) PET/CT shows better diagnostic performance for detection of lymph node and bone metastases as compared to conventional imaging. Studies of PSMA PET/CT in primary staging comprise highly selected patient cohorts. This study evaluates ¹⁸F-DCFPyL PET/CT as first-line imaging modality for primary staging of high-risk prostate cancer.

MATERIAL

From February 2018 until April 2019, all patients with high-risk prostate cancer received ¹⁸F-DCFPyL PET/CT for staging of prostate cancer. Baseline characteristics, findings at ¹⁸F-DCFPyL PET/CT, number and type of required additional diagnostic procedures, findings at additional diagnostic procedures, and effects of therapy on PSA levels for all patients treated with curative intent were collected and evaluated.

RESULTS

One hundred-sixty patients were included in the study of which 90 (56%) had evidence of metastasized disease (N1, M1a, M1b and, M1c in 49%, 28%, 31%, and 3% respectively). Additional diagnostic imaging was needed in 2/160 patients (1%) because of equivocal findings on ¹⁸F-DCFPyL PET/CT. Eighty-one patients had evidence of PSMA-positive lymph node metastases, of whom 39 (48%) had no enlarged lymph nodes on CT; ¹⁸F-DCFPyL PET detected additional metastatic lymph nodes in 41/42 patients that had evidence of lymph node metastases on CT. ¹⁸F-DCFPyL PET altered patients' management in 17% of patients.

CONCLUSION

¹⁸F-DCFPyL PET/CT can be used as first-line imaging modality for therapy selection in patients with primary high-risk prostate cancer, without need for further diagnostic imaging procedures in the majority of patients.

Lesion Detection and Interobserver Agreement with Advanced Image Reconstruction for 18F-DCFPyL PET/CT in Patients with Biochemically Recurrent Prostate Cancer

Biochemically recurrent prostate cancer (BCR) is the main indication to perform prostate-specific membrane antigen PET/CT. However, localizing BCR with prostate-specific membrane antigen PET/CT remains challenging in patients with low prostate-specific antigen (PSA) values. Here, we studied the impact of advanced PET image reconstruction methods on BCR localization and interobserver agreement with ¹⁸F-DCFPyL PET/CT scans in patients with BCR and low PSA values. Methods: Twenty-four patients with BCR and a PSA level of less than 2.0 ng/mL were included. PET images were reconstructed with 4-mm voxels and 2-mm voxels, both with and without point-spread function. All scans were interpreted by 4 nuclear medicine physicians. Additionally, PET examinations of 5 patients with primary prostate cancer and confirmed absence of lymph node metastases (after lymph node dissection) were included, to assess the risk of introducing false-positive findings when using advanced reconstruction. Calculation of BCR localization rates (scan positivity) was based on consensus among our readers (≥3 readers regarding a scan positive for BCR), as well as the individual scan interpretations of the readers. Results: In the consensus analysis, BCR localization rates were not higher using advanced reconstruction (62.5%-66.7%) than using 4-mm reconstruction (62.5%). On the basis of individual readings, however, more scans were positive using 2-mm reconstruction (74.0%; 95% confidence interval [CI], 65.0%-82.9%) (P = 0.027) and 2-mm reconstruction with point-spread function (75.0%; 95% CI, 66.2%-83.8%) (P = 0.014) than 4-mm reconstruction (65.6%; 95% CI, 56.0%-75.3%). A higher number of lesions was detected on the 2-mm scans (median, 2 lesions; interquartile range, 1-3) than the 4-mm scans (median, 1; interquartile range, 0-3; P = 0.008). The advanced reconstruction methods did not increase interobserver agreement (80.6%-84.7%), compared with the 4-mm scans (75.7%, P = 0.08-0.25). In the patients with primary prostate cancer, an equal number of false-positive lesions was observed among the different reconstruction methods (overall, n = 13). Conclusion: Applying advanced image reconstruction for ¹⁸F-DCFPyL PET/CT scans did not increase BCR localization in patients with BCR and low PSA values (reader consensus). Yet, the increased number of positive individual readings may imply that further development of image reconstruction methods holds potential to improve BCR localization. No improved interobserver agreement was observed with advanced reconstruction compared with standard 4-mm reconstruction.

Parathyroid imaging with 18F-fluorocholine PET/CT as a first-line imaging modality in primary hyperparathyroidism: a retrospective cohort study

BACKGROUND

¹⁸F-fluorocholine (FCH) PET/CT is a promising technique for visualizing hyperfunctioning parathyroid glands in hyperparathyroidism. It is still under debate whether to use this technique as a first-line imaging modality or to use it when conventional techniques such as ^99mTc-sestamibi scintigraphy or ultrasonography are inconclusive. This study evaluates FCH PET/CT as a first-line modality.

METHODS

Patients with primary hyperparathyroidism, referred between June 2015 and December 2018 for FCH PET/CT as a first-line imaging method, were included in this study. Baseline characteristics, clinical data, scan results, and type of treatment were recorded. The rate of correct detection was calculated on a per patient-based and a per lesion-based analysis. The reference standard comprised histopathological results, intraoperative response to parathyroidectomy, and clinical follow-up.

RESULTS

Two hundred and seventy-one patients were included, of which 139 patients underwent parathyroidectomy, 48 were treated with calcimimetics, and 84 patients received further follow-up without active treatment. In the surgically treated group, a single adenoma was suspected in 127 scans, double adenoma in three scans, and one scan showed evidence of three hyperfunctioning glands. In eight scans, no lesions were visualized. A total of 154 parathyroid glands were surgically removed. The rate of correct detection was calculated at 96% and 90%, on a per patient-based and per lesion-based analysis, respectively.

CONCLUSION

This retrospective study in a large cohort shows high detection rates of FCH PET/CT in primary hyperparathyroidism, which is in accordance to literature. The use of FCH PET/CT as a first-line imaging modality in preoperative planning of parathyroid surgery may therefore be a suitable choice.

Early lesion detection with 18F-DCFPyL PET/CT in 248 patients with biochemically recurrent prostate cancer

Purpose

Prostate-specific membrane antigen (PSMA) PET/CT is increasingly used in patients with biochemically recurrent prostate cancer (BCR), mostly using gallium-68 (¹⁶⁸Ga)-labelled radiotracers. Alternatively, fluorine-18 (¹⁸F)-labelled PSMA tracers are available, such as ¹⁸F-DCFPyL, which offer enhanced image quality and therefore potentially increased detection of small metastases. In this study we evaluate the lesion detection efficacy of ¹⁸F-DCFPyL PET/CT in patients with BCR and determine the detection efficacy as a function of their PSA value.

Methods

A total of 248 consecutive patients were evaluated and underwent scanning with ¹⁸F-DCFPyL PET/CT for BCR between November 2016 and 2018 in two hospitals in the Netherlands. Patients were examined after radical prostatectomy (52%), external-beam radiation therapy (42%) or brachytherapy (6%). Imaging was performed 120 min after injection of a median dose of 311 MBq ¹⁸F-DCFPyL.

Results

In 214 out of 248 PET/CT scans (86.3%), at least one lesion suggestive of cancer recurrence was detected (‘positive scan’). Scan positivity increased with higher PSA values: 17/29 scans (59%) with PSA values <0.5 ng/ml; 20/29 (69%) with PSA 0.5 to <1.0 ng/ml; 35/41 (85%) with PSA 1.0 to <2.0 ng/ml; 69/73 (95%) with PSA 2.0 to <5.0 ng/ml; and 73/76 (96%) with PSA ≥5.0 ng/ml. Interestingly, suspicious lesions outside the prostatic fossa were detected in 39–50% of patients with PSA <1.0 ng/ml after radical prostatectomy (i.e. candidates for salvage radiotherapy).

Conclusion

¹⁸F-DCFPyL PET/CT offers early detection of lesions in patients with BCR, even at PSA levels <0.5 ng/ml. These results appear to be comparable to those reported for ⁶⁸Ga-PSMA and ¹⁸F-PSMA-1007, with potentially increased detection efficacy compared to ⁶⁸Ga-PSMA for patients with PSA <2.0.

Electronic supplementary material

The online version of this article (10.1007/s00259-019-04385-6) contains supplementary material, which is available to authorized users.

Dual-Time-Point 18F-Fluorocholine PET/CT in Parathyroid Imaging

¹⁸F-fluorocholine (¹⁸F-FCH) PET/CT is a promising and increasingly used scan technique in the preoperative imaging of parathyroid adenoma. Several acquisition methods have been evaluated in the literature, but the optimal image acquisition time point after administration of the tracer is still under debate. Methods: Patients who had hyperparathyroidism, underwent dual-time-point ¹⁸F-FCH PET/CT (image acquisition, 5 min; 60 min after injection), and had histologically proven pathologic parathyroid glands were retrospectively included in the study. Early and late images were compared both visually and quantitatively. Results: Sixty-four patients were included, and a total of 71 parathyroid glands were surgically removed. Visually, there were no differences between early and late images of hyperfunctioning parathyroid glands in 44 patients (69%); in 13 patients (20%), visualization on early images was better; in 6 patients (9%), visualization of hyperfunctioning glands was best on late images; and in 1 patient (2%), the lesion was exclusively visualized on late images. For the total cohort, there was a significant decrease in ¹⁸F-FCH uptake in the glands on late versus early time points (P = 0.001), but there was a significant increase in the ratio of parathyroid uptake to thyroid uptake (P = 0.037). The group of patients with better visualization on early images showed a decrease over time in both parathyroid uptake and the ratio of parathyroid uptake to thyroid uptake, significant in comparison to those in both the group with better visualization at later time points and the group in which visualization was similar at both time points (P values of 0.000-0.018). There were no significant differences in ¹⁸F-FCH uptake and the ratio of parathyroid uptake to thyroid uptake between the latter 2 groups (P values of 0.200-0.709). Conclusion: In most patients (89%), hyperfunctioning parathyroid glands were adequately visualized on early imaging; however, in a subset of patients (11%), such glands were best visualized at later time points. Therefore, we recommend the acquisition of dual-time-point images in parathyroid imaging with ¹⁸F-FCH PET/CT or the creation of an opportunity to acquire additional late images after review of early images when findings are inconclusive.

Effects of Fasting on 18F-DCFPyL Uptake in Prostate Cancer Lesions and Tissues with Known High Physiologic Uptake

In the literature, a 4- to 6-h fast is recommended before a patient undergoes PET/CT with 2-(3-(1-carboxy-5-[(6-¹⁸F-fluoro-pyridine-3-carbonyl)-amino]-pentyl)-ureido)-pentanedioic acid (¹⁸F-DCFPyL); however, a scientific underpinning for this recommendation is lacking. Therefore, we performed a study to determine the impact of fasting on ¹⁸F-DCFPyL uptake. Methods: The study included 50 patients who fasted at least 6 h before ¹⁸F-DCFPyL administration and 50 patients who did not. Activity (SUV_max) was measured in lesions characteristic of prostate cancer and in normal tissues known to express high physiologic uptake. Results: Uptake in suspected lesions did not differ between the cohorts. ¹⁸F-DCFPyL uptake in the submandibular gland, liver, and spleen was significantly higher in the fasting than the nonfasting cohort. Conclusion: Our data show that fasting does not significantly affect ¹⁸F-DCFPyL uptake in suspected malignant lesions but does result in significantly lower ¹⁸F-DCFPyL uptake in tissues with high physiologic uptake. The absolute differences in uptake were relatively small; therefore, the effects of fasting on the diagnostic performance can be considered negligible.

Exercise Electrocardiogram Neither Predicts Nor Excludes Coronary Artery Disease in Women with Low to Intermediate Risk

AIM

The value of exercise electrocardiogram (ExECG) in symptomatic female patients with low to intermediate risk for significant coronary artery disease (CAD) has been under debate for many years, and nondiagnostic or even erroneous test results are frequently encountered. Cardiac-CT may be more appropriate to exclude CAD in women. This study compares the results of ExECGs with those of cardiac-CTs, performed within a time frame of 1 month in an all-comers female chest pain population.

PATIENTS AND METHODS

Five hundred fifty-one consecutive female patients from a patient registry were included. ExECGs were negative in 324 (59%), positive in 14 (3%), and nondiagnostic in 213 (39%) patients. CAD was revealed by cardiac-CT in 57% of the women with negative ExECG. No signs of CAD were present on cardiac-CT in 64% of the women with a positive ExECG. Cardiac-CT showed presence of CAD in 268/551 (49%) patients, of whom 56/268 (21%) was diagnosed with ≥50% stenosis. The ExECG of the latter group was negative in 26 (46%), inconclusive in 29 (52%), and positive in 1 (2%). Considering ≥50% stenosis at cardiac-CT as the reference, sensitivity, specificity, PPV, and NPV of ExECG for the present population were 3.7%, 95.7%, 7.1%, and 91.7%, respectively. Similar diagnostic performance was calculated when considering ≥70% stenosis at cardiac-CT as the reference.

CONCLUSION

ExECG failed to detect CAD in more than half of this cohort and in almost half of women with >50% stenosis at cardiac-CT. Importantly, no CAD was detected by cardiac-CT in 64% of women with a positive ExECG. ExECG is therefore questionable as a diagnostic strategy in women with low-to-intermediate risk of CAD, although prospective studies are warranted to determine whether replacing ExECG by cardiac-CT provides better prognoses.

Incidental extra-cardiac findings on 13N-ammonia myocardial perfusion PET/CT

BACKGROUND

The objective of this study was to describe the prevalence of incidental extra-cardiac findings (IECFs) on myocardial perfusion PET/CTs and the prevalence of potentially clinically relevant and clinically irrelevant IECFs, as well as detection rate of previously unknown malignancies.

METHODS AND RESULTS

From September 2013 until February 2016, a total of 1397 consecutive patients referred for the evaluation of possible ischemia by 13NH3 PET/CT were prospectively included in a database. IECFs were categorized into three groups: potentially clinically relevant IECFs, IECFs that could potentially cause chest pain, and clinically irrelevant IECFs. Additionally, the prevalence of previously unknown malignancies was determined. In 717 (51%) of these patients, 775 IECFs were reported and 115 IECFs were categorized as potentially clinically relevant in 109 (8%) patients. A total of 145 IECFs that could potentially cause chest pain were detected in 139 (10%) patients and 515 clinically irrelevant IECFs were detected in 469 (34%) of the patients. An unknown primary malignancy was histologically proven in 19 patients (1.4%).

CONCLUSIONS

IECFs are detected on myocardial perfusion PET/CT in approximately half of the patients. In the present study, IECFs were potentially clinically relevant in 8% of the patients and in 1.4% an unknown malignancy was found, most of which were lung cancers.

18F-DCFPyL PET/CT in the Detection of Prostate Cancer at 60 and 120 Minutes: Detection Rate, Image Quality, Activity Kinetics, and Biodistribution

There is increasing interest in PET/CT with prostate-specific membrane antigen (PSMA) tracers for imaging of prostate cancer because of the higher detection rates of prostate cancer lesions than with PET/CT with choline. For ⁶⁸Ga-PSMA-11 tracers, late imaging at 180 min after injection instead of imaging at 45-60 min after injection improves the detection of prostate cancer lesions. For ¹⁸F-DCFPyL, improved detection rates have recently been reported in a small pilot study. In this study, we report the effects of PET/CT imaging at 120 min after injection of ¹⁸F-DCFPyL in comparison to images acquired at 60 min after injection in a larger clinical cohort of 66 consecutive patients with histopathologically proven prostate cancer. Methods: Images were acquired 60 and 120 min after injection of ¹⁸F-DCFPyL. We report the positive lesions specified for anatomic locations (prostate, seminal vesicles, local lymph nodes, distant lymph nodes, bone, and others) at both time points by visual analysis, the image quality at both time points, and a semiquantitative analysis of the tracer activity in both prostate cancer lesions as well as normal tissues at both time points. Results: Our data showed a significantly increasing uptake of ¹⁸F-DCFPyL between 60 and 120 min after injection in 203 lesions characteristic for prostate cancer (median, 10.78 vs. 12.86, P < 0.001, Wilcoxon signed-rank test). By visual analysis, 38.5% of all patients showed more lesions using images at 120 min after injection than using images at 60 min after injection, and in 9.2% a change in TNM staging was found. All lesions seen on images 60 min after injection were also visible on images 120 min after injection. A significantly better mean signal-to-noise ratio of 11.93 was found for images acquired 120 min after injection (P < 0.001, paired t test; signal-to-noise ratio at 60 min after injection, 11.15). Conclusion:¹⁸F-DCFPyL PET/CT images at 120 min after injection yield a higher detection rate of prostate cancer characteristic lesions than images at 60 min after injection. Further studies are needed to elucidate the best imaging time point for ¹⁸F-DCFPyL.

Impact of fasting on (18)F-fluorocholine gastrointestinal uptake and detection of lymph node metastases in patients with prostate cancer

Background

¹⁸F-fluorocholine PET/CT is used to detect lymph node metastases in prostate cancer patients. Physiological ¹⁸F-fluorocholine in the gastrointestinal tract, especially in the intestines, may interfere with the detection of malignant lymph nodes. Fasting is frequently proposed in literature; however, scientific support is lacking. This study aims to determine the impact of fasting on ¹⁸F-fluorocholine uptake in the gastrointestinal tract.

Methods

Eighty patients were studied, 40 fasted for at least 6 h prior to ¹⁸F-fluorocholine administration while the other 40 did not fast. ¹⁸F-fluorocholine uptake pattern and intensity were evaluated in the intestine near the abdominal aorta and four regions near the iliac arteries. ¹⁸F-fluorocholine intensity was also measured in the liver, pancreas, stomach and spleen.

Findings

No statistically significant differences were found in ¹⁸F-fluorocholine uptake in the gastrointestinal tract between the fasting and non-fasting group.

Conclusions

Fasting for 6 h has no effect on ¹⁸F-fluorocholine uptake in the gastrointestinal tract. Therefore, no effects on the detection of malignant lymph nodes are expected, and fasting is not recommended in our opinion.

Evaluation of gastrectomy in patients with delayed gastric emptying after antireflux surgery or large hiatal hernia repair

BACKGROUND

Revision antireflux surgery and large hiatal hernia repair require extensive dissection at the gastroesophageal junction. This may lead to troublesome symptoms due to delayed gastric emptying, eventually requiring gastrectomy. The aim of this study was to evaluate the outcome of gastrectomy for severely delayed gastric emptying after large hiatal hernia repair or redo antireflux surgery.

METHODS

Eleven patients were treated between 1995 and 2010 and entered in the study. Preoperative and operative data were retrospectively collected. Standardized questionnaires were sent to all of the patients to evaluate symptomatic outcome.

RESULTS

The primary intervention was Nissen fundoplication in nine patients, Toupet fundoplication in one, and cruroplasty in another. The repairs were for refractory gastroesophageal reflux disease in five patients and a symptomatic large hiatal hernia in six. Subsequent gastrectomy was partial in four patients, subtotal in six, and total in one. There was one minor postoperative complication. After a mean (±SD) duration of 102 ± 59 months, nine patients were available for symptomatic follow-up. Eight patients experienced daily symptoms related to dumping. Daily symptoms indicative of delayed gastric emptying were present in seven patients at follow-up. Mean general quality of life was increased from 3.8 ± 2.2 before gastrectomy to 5.4 ± 1.8 at follow-up. Eight patients reported gastrectomy as worthwhile.

CONCLUSION

Gastrectomy after previous antireflux surgery or large hiatal hernia repair is safe with the potential to improve quality of life. Although upper gastrointestinal symptoms tend to persist, gastrectomy can be considered a reasonable, last-resort surgical option for alleviating upper gastrointestinal symptoms after this kind of surgery.

99mTc-macroaggregated albumin poorly predicts the intrahepatic distribution of 90Y resin microspheres in hepatic radioembolization

In hepatic (90)Y radioembolization, pretreatment (99m)Tc-macroaggregated albumin ((99m)Tc-MAA) nuclear imaging is used for lung shunt analysis, evaluation of extrahepatic deposition, and sometimes for treatment planning, using a partition model. A high level of agreement between pretreatment (99m)Tc-MAA distribution and final (90)Y-microsphere distribution is assumed. The aim of this study was to investigate the value of pretreatment (99m)Tc-MAA SPECT to predict intrahepatic posttreatment (90)Y-microsphere distribution.

METHODS

Volumes of interest (VOIs) were delineated on pretreatment contrast-enhanced CT or MR images according to Couinaud liver segmentation. All VOIs were registered to the (99m)Tc-MAA SPECT and (90)Y SPECT images. The (99m)Tc-MAA SPECT and (90)Y SPECT activity counts were normalized to the total administered activity of (90)Y. For each VOI, this practice resulted in a predictive amount of (90)Y (MBq/cm(3)) based on (99m)Tc-MAA SPECT in comparison with an actual amount of (90)Y based on (90)Y SPECT. Bland-Altman analysis was used to investigate the agreement of the activity distribution between (99m)Tc-MAA SPECT and (90)Y SPECT.

RESULTS

A total of 39 procedures (225 VOIs) in 31 patients were included for analysis. The overall mean difference between pretreatment and posttreatment distribution of activity concentration for all segments was -0.022 MBq/cm(3) with 95% limits of agreement of -0.581 to 0.537 MBq/cm(3) (-28.9 to 26.7 Gy absorbed dose). A difference of >10%, >20%, and >30% of the mean activity per milliliter was found in, respectively, 153 (68%), 97 (43%), and 72 (32%) of the 225 segments. In every (99m)Tc-MAA procedure, at least 1 segment showed an under- or overestimation of >10%. The position of the catheter tip during administrations, as well as the tumor load of the liver segments, significantly influenced the disagreement.

CONCLUSION

In current clinical practice, (99m)Tc-MAA distribution does not accurately predict final (90)Y activity distribution. Awareness of the importance of catheter positioning and adherence to specific recommendations may lead to optimization of individualized treatment planning based on pretreatment imaging.