Comparison of CT and PET/CT for biopsy guidance in oncological patients

High early mortality after percutaneous liver biopsy in metastatic cancer: national analysis

OBJECTIVE

The study aimed to assess outcomes in patients undergoing liver biopsy for metastatic cancer, focusing on mortality rates and chemotherapy following their biopsy.

METHODS

Hospital Episode Statistics data from 2010 to 2019 identified 30 992 patients with metastatic cancer who underwent percutaneous liver biopsy. Primary outcomes included 14-day and 30-day mortality rates, as well as the proportion receiving chemotherapy within 6 months.

RESULTS

30 992 patients were studied (median age of 69 (IQR 59-74) years, 52% female). 28% underwent inpatient biopsy with 8% dying within 14 days and 26% within 30 days. Outpatient biopsies had lower mortality rates: 2.2% at 14 days and 8.6% at 30 days.30-day mortality was associated with: inpatient biopsy (OR 3.5 (95% CI 3.26 to 3.76)) and increasing comorbidity (Charlson score 1-4: 1.21 (95% CI 1.11 to 1.32)); but negatively with all ages under 70 (eg, for 18-29 years 0.35 (95% CI 0.20 to 0.63)) and biopsy at a radiotherapy centre (0.88 (95% CI 0.82 to 0.95)).46% of patients received chemotherapy within 6 months of biopsy (53% with outpatient biopsies but only 33% with inpatient biopsies). Receiving chemotherapy was associated with: all ages under 70 (eg, 18-29 years 3.3 (95% CI 2.62 to 5.30)), female sex (1.06 (95% CI 1.01 to 1.11)) and medium (1.13 (95% CI 1.04 to 1.22) and high (1.49 (95% CI 1.38 to 1.62)) volume liver biopsy providers; but negatively with inpatient biopsy (0.45 (95% CI 0.43 to 0.48)) and increasing comorbidity (Charlson score 1-4: 0.85 (95% CI 0.79 to 0.91)).

CONCLUSIONS

Mortality rates following liver biopsy for metastatic cancer are notably higher among patients undergoing emergency inpatient procedures. Clinicians should carefully weigh the risks and benefits of biopsy in elderly, comorbid or poor performance status patients. Multidisciplinary approaches involving palliative care may aid in decision-making for these patients.

Augmenting CT-Guided Bone Biopsies Using 18F-FDG PET/CT Guidance

Computer tomography (CT)-guided percutaneous core biopsies are currently the gold standard in diagnostic procedures for patients with bone lesions of unknown kind. CT-guided biopsies can lead to misdiagnosis or repetition of biopsies in case of small or heterogeneous lesions. We hypothesize that molecular image guidance could be used to optimize the biopsy strategy, by supporting the detection of heterogeneous lesions or lesions without radiographic substrate. To evaluate this hypothesis, we investigated if and how the addition of 2-deoxy-2-18F-fluoro-D-glucose-positron emission tomography (18F-FDG-PET)/CT could augment routine CT-guided bone biopsies. To this end, 106 patients who underwent a CT-guided bone biopsy between April 2019 and April 2020, obtained from either a vertebral or peripheral bone, were included. Patients were divided into 2 groups: 36 patients received an 18F-FDG-PET/CT scan prior to their CT-guided bone biopsy (PET group), while 70 patients only had a morphological CT scan (CT group). Histopathology was used to categorize biopsies into five subgroups (inconclusive, benign, malignant or infectious disease, or normal tissue). In the PET group, the number of conclusive biopsies was significantly higher compared to the CT group (N = 33/36 (92%) versus N = 53/70 (76%); p < 0.05). Furthermore, the number of first-try biopsies was lower in the PET group compared to the CT group (1.9 vs. 2.54, p = 0.051). In conclusion, 18F-FDG-PET/CT imaging significantly increased the success rate of first-try CT-guided bone biopsies by showing less inconclusive biopsies and misdiagnosis.

Molecular Imaging in Soft-tissue Sarcoma: Evolving Role of FDG PET

Soft tissue sarcomas are a rare and heterogenous group of tumors that account for 2% of all cancer-related deaths. Molecular imaging with FDG PET can offer valuable metabolic information to help inform clinical management of soft tissue sarcomas that is unique and complementary to conventional diagnostic imaging techniques. FDG PET imaging often correlates with tumor grade, can help guide biopsy, and frequently detects additional sites of disease compared to conventional imaging in patients being considered for definitive or salvage therapy. Traditional size-based evaluation of treatment response is often inadequate in soft tissue sarcoma and changes in metabolic activity can add significant value to interim and end of treatment imaging for high-grade sarcomas. FDG PET can be used for detection of recurrence or malignant transformation and thus play a vital role in surveillance. This article reviews the evolving role of FDG PET in initial diagnosis, staging, treatment response assessment, and restaging. Further studies on the use of FDG PET in soft sarcoma are needed, particularly for rare histopathologic subtypes.

18F-FDG PET/CT anatomic and metabolic guidance in CT-guided lung biopsies

PURPOSE

To evaluate the role of Fluorine-18 fluorodeoxyglucose (18F-FDG) PET/CT as a metabolic guide in increasing the accuracy, diagnostic yield and safety of CT-guided percutaneous needle lung biopsy (PNB).

METHODS AND MATERIALS

Retrospective analysis of 340 consecutive patients with suspicious lung nodules, masses or extensive disease that underwent lung biopsy over a 3-year period. Patients were divided into three groups; those that had PET/CT prior to the biopsy, those that had PET-CT following the biopsy and those who did not undergo PET-CT. Correlation was made with the histopathological result.

RESULTS

353 PNBs were performed (median lesion size 30 mm, 7-120 mm) with overall diagnostic rate of 83.9 % (95.8 % malignant). Biopsy success rate was 88.8 % with PET-CT pre-PNB, versus 78.9 % of 175 PNB without PET-CT upfront (p < 0.01 Fisher exact test). Correct targeting to PET-CT-maximum activity area (MAA) was present in 87.1 %. Biopsy success rate was 88.8 % for PNBs targeting the PET-CT-MAA region and only 52.8 % for PNBs not targeting the PET-CT-MAA (p < 0.0001). PET-CT pre-PNB had higher rates of PET-CT-MAA targeting compared to PET-CT post PNB (91.0 % v 80.0 %, p = 0.01). The availability of PET-CT before the PNB lead to significantly increased biopsy success rates in patients with a mass (OR:7.01p = 0.004), compared to a nodule (p = 0.498) or multiple nodules (p = 0.163). Patients with a PET-CT pre-PNB underwent fewer PNB passes (mean 2.6 v 3.1, p < 0.0001 Mann Whitney U). Serious complications were less common in PET-CT pre-PNB group (4.5 % v 10.9 %, p < 0.05). Pre-PNB PET-CT performance improvement applied to all 3 radiologists and was greatest for masses and infiltrative abnormalities.

CONCLUSION

Metabolic information provided by 18F-FDG PET/CT and PNB localisation to the PET-CT maximum activity region is associated with higher diagnostic biopsy rates especially in masses and appears to account for improved performance, less needle passes and complications when available pre-biopsy.

Current status and future expectations of nanobodies in oncology trials

INTRODUCTION

Monoclonal antibodies have revolutionized personalized medicine for cancer in recent decades. Despite their broad application in oncology, their large size and complexity may interfere with successful tumor targeting for certain applications of cancer diagnosis and therapy. Nanobodies have unique structural and pharmacological features compared to monoclonal antibodies and have successfully been used as complementary anti-cancer diagnostic and/or therapeutic tools.

AREAS COVERED

Here, an overview is given of the nanobody-based diagnostics and therapeutics that have been or are currently being tested in oncological clinical trials. Furthermore, preclinical developments, which are likely to be translated into the clinic in the near future, are highlighted.

EXPERT OPINION

Overall, the presented studies show the application potential of nanobodies in the field of oncology, making it likely that more nanobodies will be clinically approved in the upcoming future.

The Role of PET-CT-Guided Metabolic Biopsies in Improving Yield of Inconclusive Anatomical Biopsies: A Review of 5 Years in a Teaching Hospital

Tumour sampling is indispensable to diagnostic and therapeutic decision making. Thus, 18F-FDG PET/CT has the potential to accurately discriminate between viable and non-viable tissues due to its ability to characterise the metabolism of visible tissues. This study's objective was to evaluate the incremental utility of 18F-FDG PET-CT-guided metabolic biopsy in individuals with suspected lesions and a previous negative anatomical biopsy. This study included a total of 190 consecutive patients with probable malignancy and who had experienced a previous unsuccessful anatomical biopsy who underwent PET-CT-guided metabolic biopsy. We retrospectively analysed the patients' medical records and imaging investigations to assess demographics, complications, pathologies, and final clinical diagnoses. Using multivariate logistic regression, correlation between several confounding factors that lead to post-procedural problems was evaluated. Adequate material was obtained in all patients, and 162 (85%) were found to be positive for malignancy with a diagnostic yield of 96.9%. In 25 (13.1%) patients, post-procedural complications were reported, with pneumothorax being the most prevalent issue. In evaluating oncological patients, metabolic biopsy provides a safer alternative therapy with a high diagnostic yield and comparable complications. PET-CT, being an essential component of cancer staging, may serve as a one-stop shop for the management of these patients' conditions.

Could Maximum SUV be Used as Imaging Guidance in Large Lung Lesions Biopsies? Double Sampling Under PET-CT/XperGuide Fusion Imaging in Inhomogeneous Lung Uptaking Lesions to Show That it can Make a Difference

Introduction: The purpose of this study is to evaluate the diagnostic value of positron emission computed tomography-cone beam computed tomography (PET/CT-CBCT) fusion guided percutaneous biopsy, targeted to the maximum standardized uptake value (SUVmax) and minimum standardized uptake value (SUVmin) of large lung lesions. Materials and Methods: Inside a larger cohort of PET/CT-CBCT guided percutaneous lung biopsies, 10 patients with large pulmonary lesions (diameter > 30 mm) were selected retrospectively. These patients have been subjected to double biopsy sampling respectively in the SUVmax area and in the SUVmin area of the lesion. Technical success has been calculated. For each sample, the percentage of neoplastic, inflammatory, and fibrotic cells was reported. Furthermore, the possibility of performing immunohistochemical or molecular biology investigations to specifically define the biomolecular tumor profile was analyzed. Results: Nine lesions were found to be malignant, one benign (inflammation). Technical success was 100% (10/10) in the SUVmax samples and 70% (7/10) in the SUVmin samples (P-value: .21). In the first group, higher percentages of neoplastic cells were found at pathologic evaluation, while in the second group areas of inflammation and fibrosis were more represented. The biomolecular profile was obtained in 100% of cases (9/9) of the first group, while in the second group only in 33.3% of cases (2/6), with a statistically significant difference between the 2 groups (P-value: .011). Conclusion: A correlation between the standardized uptake value value and the technical success of the biopsy sample has been identified. PET/CT-CBCT guidance allows to target the biopsy in the areas of the tumor which are richer in neoplastic cells, thus obtaining more useful information for the planning of patient-tailored cancer treatments.

Expert opinion on NSCLC small specimen biomarker testing - Part 1: Tissue collection and management

Biomarker testing is crucial for treatment selection in advanced non-small cell lung cancer (NSCLC). However, the quantity of available tissue often presents a key constraint for patients with advanced disease, where minimally invasive tissue biopsy typically returns small samples. In Part 1 of this two-part series, we summarise evidence-based recommendations relating to small sample processing for patients with NSCLC. Generally, tissue biopsy techniques that deliver the greatest quantity and quality of tissue with the least risk to the patient should be selected. Rapid on-site evaluation can help to ensure sufficient sample quality and quantity. Sample processing should be managed according to biomarker testing requirements, because tissue fixation methodology influences downstream nucleic acid, protein and morphological analyses. Accordingly, 10% neutral buffered formalin is recommended as an appropriate fixative, and the duration of fixation is recommended not to exceed 24-48 h. Tissue sparing techniques, including the 'one biopsy per block' approach and small sample cutting protocols, can help preserve tissue. Cytological material (formalin-fixed paraffin-embedded [FFPE] cytology blocks and non-FFPE samples such as smears and touch preparations) can be an excellent source of nucleic acid, providing either primary or supplementary patient material to complete morphological and molecular diagnoses. Considerations on biomarker testing, reporting and quality assessment are discussed in Part 2.

Improving CT-guided transthoracic biopsy diagnostic yield of lung masses using intraprocedural CT and prior PET/CT fusion imaging

Objective

The purpose of this study was to evaluate the usefulness of intraprocedural CT and prior PET/CT fusion imaging in improving the diagnostic yield of CT-guided transthoracic core-needle biopsy (CNB) in lung masses.

Methods

In total, 145 subjects with lung masses suspicious for malignancy underwent image-guided transthoracic CNB. According to imaging modality the subjects were divided into two groups. PET/CT images obtained no more than 14 days before the biopsy were integrated with intraprocedural CT images. The integrated or fused images were then used to plan the puncture sites. The clinical characteristics, diagnostic yield of CNB, diagnostic accuracy rate, procedure-related complications and procedure duration were recorded and compared between the two groups. Final clinical diagnosis was determined by surgical pathology or at least 6-months follow-up. The diagnostic accuracy of CNB was obtained by comparing with final clinical diagnosis.

Results

145 subjects underwent CNB with adequate samples, including 76 in fusion imaging group and 69 in routine group. The overall diagnostic yield and diagnostic accuracy rate were 80.3% (53/66), 82.9% (63/76) for fusion imaging group, 70.7% (41/58), 75.4% (52/69) for routine group, respectively. In addition, the diagnostic yield for malignancy in fusion imaging group (98.1%, 52/53) was higher than that in routine group (81.3%, 39/48). No serious procedure-related complications occurred in both two groups.

Conclusion

CNB with prior PET/CT fusion imaging is particularly helpful in improving diagnostic yield and accurate rate of biopsy in lung masses, especially in heterogeneous ones, thus providing greater potential benefit for patients.

Role of Image-Guided Percutaneous Needle Biopsy in the Age of Precision Medicine

PURPOSE OF REVIEW

With the remarkable progress in cancer precision medicine, the demand for biopsy has been increasing, and the role of biopsy has been changing. In this review, we discuss the current state and recent advances in the role of image-guided percutaneous needle biopsy (PNB) in facilitating precision medicine.

RECENT FINDINGS

Biopsies are useful not only in the diagnosis of cancer and histological sub-type but also in the analysis of its molecular characteristics for targeted treatments. PNB specimens have been shown to provide high DNA yields for genomic analysis. Liquid biopsy is an emerging technology but is under development; therefore, PNB is the current standard of practice and is performed complimentarily with liquid biopsy. In the age of precision medicine, interventional oncologists play a key role in optimal tissue collection for adequate genomic analysis. Effective PNB may improve its diagnostic utility and help optimize precision medicine.

Current trends and perspectives in interventional radiology for gastrointestinal cancers

Gastrointestinal (GI) cancers often require a multidisciplinary approach involving surgeons, endoscopists, oncologists, and interventional radiologists to diagnose and treat primitive cancers, metastases, and related complications. In this context, interventional radiology (IR) represents a useful minimally-invasive tool allowing to reach lesions that are not easily approachable with other techniques. In the last years, through the development of new devices, IR has become increasingly relevant in the context of a more comprehensive management of the oncologic patient. Arterial embolization, ablative techniques, and gene therapy represent useful and innovative IR tools in GI cancer treatment. Moreover, IR can be useful for the management of GI cancer-related complications, such as bleeding, abscesses, GI obstructions, and neurological pain. The aim of this study is to show the principal IR techniques for the diagnosis and treatment of GI cancers and related complications, as well as to describe the future perspectives of IR in this oncologic field.

Estimation of patient effective doses in PET/CT- 18F-Sodium Fluoride examinations

The positron emitters (¹⁸F-Sodium Fluoride (NaF)) and X-rays used in Positron emission tomography (PET) combined with computed tomography (PET/CT) imaging have a high radiation dose, which results in a high patient dose. The present research intends to determine the radiation dose and risks associated with PET/CT- 18F-Sodium fluoride examinations in patients. The 18F-NaF PET/CT was used to investigate the doses of 86 patients. Patient exposure parameters and ImPACT software were used to calculate mean effective doses. The administered activity of 185 MBq (5.0 mCi) per procedure has a mean and range based on the patient's BMI (BMI). The range of patient effective doses per procedure was found to be 4-10 mSv, with a radiation risk of 1 × 10^-5 per procedure. Patient doses are determined by the patient's size, scanner type, imaging protocol, and reconstruction method. For further dose reduction, proper justification and radiation dose optimization is required.

PET/CT-Guided Biopsy of Suspected Lung Lesions Requires Less Rebiopsy Than CT-Guided Biopsy Due to Inconclusive Results

The purpose of this study was to compare 18F-FDG PET/CT and CT performance in guiding percutaneous biopsies with histologic confirmation of lung lesions. Methods: We prospectively evaluated 341 patients, of whom 216 underwent 18F-FDG PET/CT-guided biopsy and 125 underwent CT-guided biopsy. The pathology results, lesion size, complications, and rebiopsy rate in the 2 groups were evaluated. Results: Of the 216 biopsies with PET/CT guidance, histology demonstrated 170 lesions (78.7%) to be malignant and 46 (21.3%) to be benign. In the CT-guided group, of 125 lesions, 77 (61.6%) were malignant and 48 (38.4%) were benign (P = 0.001). Inconclusive results prompted the need for a second biopsy in 18 patients: 13 of 125 (10.4%) in the CT group and 5 of 216 (2.3%) in PET group (P = 0.001). Complications were pneumothorax (13.2%), hemothorax (0.8%), and hemoptysis (0.6%). No life-threatening adverse events or fatalities were reported. The difference in complication rates between the 2 groups was not significant (P = 0.6). Malignant lesions showed a greater mean size than benign lesions regardless of the group (P = 0.015). Conclusion: PET/CT-guided biopsy of lung lesions led to fewer inconclusive biopsies than CT-guided biopsy, with similar complication rates.

Practice and prospects for PET/CT guided interventions

During the past 10 years, performing real-time molecular imaging with positron emission tomography (PET) in combination with computed tomography (CT) during interventional procedures has undergone rapid development. Keeping in mind the interest of the nuclear medicine readers, an update is provided of the current workflows using real-time PET/CT in percutaneous biopsies and tumor ablations. The clinical utility of PET/CT guided biopsies in cancer patients with lung, liver, lymphoma, and bone tumors are reviewed. Several technological developments, including the introduction of new PET tracers and robotic arms as well as opportunities provided through acquiring radioactive biopsy specimens are briefly reviewed.

PET/CT-Guided Tissue Sampling in Patients With a Failed or Inconclusive CT-Guided Procedure: Outcomes and Contributing Factors

BACKGROUND

CT-guided tissue sampling is a very effective tool. However, false-negative results are obtained when regions such as necrotic core or surrounding reactive fibrosis and inflammation are sampled. PET/CT-guided sampling can circumvent these limitations.

PURPOSE

The aim of this study was to analyze the effectiveness of PET/CT-guided sampling in patients with at least 1 instance of failed or inconclusive CT-guided procedure and factors determining the accurate sampling and complications.

METHODS

One hundred eleven patients were prospectively included. After feasibility analysis in a diagnostic F-FDG PET/CT, sampling was performed in 106 patients (45 women, 61 men; mean age, 48.09 ± 15.42 years; biopsy in 80 and fine-needle aspiration cytology [FNAC] in 26 patients), using robotic arm and a lower IV injection dose of 74 to 111 MBq (2-3 mCi) F-FDG. In all patients, final check scans revealed needle at the target site. Using planned needle path as reference, deviations in first check scan were measured. Patient (n = 30) and respiratory motion (n = 57) were also recorded.

RESULTS

Accurate lesion targeting was achieved in 81 cases (63 positive lesions, 12 confounding lesions, and 7 inadequate samples). Lesion was missed in 5 instances, and blood/necrotic tissue sampled in 19. Overall F-FDG-avid lesions were accurately targeted in 77.36% of patients (86.25% [biopsy] + 50% [FNAC]). Significant variables affecting targeting were needle gauge, deviation from intended entry point, procedure duration, procedure type, and patient movement. Using binomial regression, the significant parameters were procedure type (biopsy vs FNAC; odds ratio [OR], 5.916; P = 0.002), patient movement (OR, 0.275; P = 0.023), and procedure duration (OR, 1.195; P = 0.011). Overall complication rate was 21.70%, with 4.71% major complications. It was dependent on target depth (mean depth, 69.74 ± 20.29 mm [complications] vs 47.18 ± 22.60 mm; P < 0.001). Positive correlation was seen between the target depth and distance of needle from the intended target (Spearman ρ = 0.307; P = 0.001). In 28 procedures, the physician was asked to wear a pocket dosimeter, who received a mean dose of 2.52 (SD, 3.10) μSv.

CONCLUSIONS

PET/CT-guided sampling should be considered where CT-guided biopsy has failed or is inconclusive. The outcome is impacted by needle gauge and patient movement, and complication rate is dependent on target depth.

Comparison Between CBCT and Fusion PET/CT-CBCT Guidance for Lung Biopsies

PURPOSE

To establish the feasibility of performing percutaneous biopsy of lung lesions guided by fusion PET/CT-CBCT and to evaluate whether the metabolic information provided by a prior PET/CT scan add incremental benefits for diagnosis.

METHODS

We retrospectively reviewed data from 180 patients who underwent CBCT-guided lung biopsy (group 1-90 cases) or PET/CT-CBCT fusion-guided lung biopsy (group 2-90 cases). Technical and clinical success was calculated. We also evaluated the agreement between biopsy and definitive histology and the possibility to carrying out immunehistochemical and molecular biology analyses.

RESULTS

Technical success was achieved in 84/90 (93.3%) cases for group 1 and 89/90 (98.9%) for group 2 cases (p 0.054). Clinical success was achieved in 80/94 (95.2%) cases for group 1 and 88/89 (98.9%) cases for group 2. Sensitivity, specificity, positive and negative predictive values and accuracy rate were, respectively, 94.5%, 100.0%, 100.0%, 73.3% and 95.2% for group 1 and 98.6%, 100.0%, 100.0%, 94.4% and 98.9% for group 2 (p 0.167). Agreement between biopsy and definitive histology was reached in 85.7% for group 1 and in 96.2% for group 2 (p 0.211). Immunohistochemical and molecular biology investigations were possible in 66.7% for group 1 and in 77.0% for group 2 (p 0.297). No major complication occurred.

CONCLUSIONS

PET/CT-CBCT-guided lung biopsy is a feasible technique. In our retrospective case series, we found a higher clinical success rate, but no statistical difference was found.

Diagnostic accuracy of positron emission tomography/computed tomography-driven biopsy for the diagnosis of lymphoma

Introduction

Biopsy of affected tissue is required for lymphoma diagnosis and to plan treatment. Open incisional biopsy is traditionally the method of choice. Nevertheless, it requires hospitalization, availability of an operating room, and sometimes general anesthesia, and it is associated with several drawbacks. Fluorodeoxyglucose positron emission tomography/computed tomography (PET/CT) can be potentially used to drive biopsy to the most metabolically active area within a lymph node or extranodal masses.

Methods

A study of diagnostic accuracy was conducted to assess the performance of a PET-driven needle biopsy in patients with suspect active lymphoma.

Results

Overall, 99 procedures have been performed: three (3.0%) were interrupted because of pain but were successfully repeated in two cases. Median SUVmax of target lesions was 10.7. In 84/96 cases, the tissue was considered adequate to formulate a diagnosis (diagnostic yield of 87.5%) and to guide the following clinical decision. The target specimen was a lymph node in 60 cases and an extranodal site in 36. No serious adverse events occurred. The sensitivity of this procedure was 96%, with a specificity of 100%, a positive predictive value of 100%, and a negative predictive value of 75%.

Conclusion

Patients can benefit from a minimally invasive procedure which allows a timely and accurate diagnosis of lymphoma at onset or relapse.

Positron emission tomography/computed tomography guided percutaneous biopsies of Ga-68 avid lesions using an automated robotic arm

PURPOSE

The purpose of this prospective study was to evaluate the feasibility of positron emission tomography/computed tomography (PET/CT)-guided biopsy of Ga-68 avid lesions using an automated robotic arm and determine the diagnostic yield of this technique.

MATERIAL AND METHODS

Patients who underwent Ga-68 labelled tracers imaging followed by PET/CT-guided biopsies of tracer-avid lesions were prospectively included. Biopsies were performed using a dedicated automated-robotic-arm assisted PET/CT-guided biopsy device on the same-day of diagnostic PET/CT-imaging. The tissue samples were retrieved after confirming the position of needle-tip in the target lesion. Procedure-related complications and radiation exposure of the interventionist were recorded. Histopathological reports were reviewed for diagnostic yield.

RESULTS

A total of 25 patients (19 men, six women) with a mean age of 50.8±17.3 (SD) years (range: 17-83 years) were included. The biopsies were performed after PET/CT using Ga-68 DOTANOC (n=16) or Ga-68 PSMA (n=8) and Ga-68 chemokine-analogue (n=1). The biopsy samples were obtained from the liver (n=9), bone (n=8), lymph-nodes (n=3), lung (n=1), pancreas (n=1), anterior mediastinal lesion (n=1), peritoneal-deposit (n=1) and thigh-lesion (n=1). No immediate or delayed procedure-related complications were documented in any patient. PET/CT-guided molecular sampling was technically successful in all the patients. Histopathology revealed malignancies in all the biopsied specimens without the need for repeat sampling or further invasive-diagnostic workup, with a diagnostic yield of 100%. The estimated absorbed-radiation dose was 566.7μSv/year for the interventionist.

CONCLUSION

PET/CT-guided molecular biopsy using Ga-68 labelled radiotracers is feasible and can be performed safely and accurately with a high-diagnostic yield. It is helpful in accurately staging the disease when tracer-avid isolated distant lesion evident on imaging and highly practical in patients with previous inconclusive sampling.

PET/CT-guided versus CT-guided percutaneous core biopsies in the diagnosis of bone tumors and tumor-like lesions: which is the better choice?

OBJECTIVE

The present study aimed to evaluate the diagnostic performance and safety of PET/CT-guided percutaneous core bone biopsy and to compare the PET/CT-guided method to conventional CT-guided percutaneous core biopsies to diagnose Chinese patients with bone tumors and tumor-like lesions.

METHODS

Data for 97 patients with bone tumors and tumor-like lesions diagnosed by percutaneous core bone biopsy from February 2013 to November 2018 were retrospectively analyzed. The study included 42 cases in the PET/CT group and 55 cases in the CT alone group. The diagnostic performance, cost and complications associated with the intervention were compared between the two groups. All patients were eventually confirmed to have bone tumors and tumor-like lesions according to surgical pathology findings.

RESULTS

There were no significant differences in patient characteristics (P > 0.05). For the patients in the PET/CT group, the overall diagnostic yield of the initial biopsies and the diagnostic accuracy derived from the surgically proven cases were both 97.62%, which was significantly higher than the values in the CT group during the same period (P < 0.05). No major biopsy-related complications (e.g., serious bleeding or tumor dissemination) occurred before, during, or after the intervention. Therefore, no significant difference was observed between the two groups with regard to the complication rate (P > 0.05).

CONCLUSION

Compared with CT-guided percutaneous bone biopsy, PET/CT-guided percutaneous bone biopsy is an effective and safe alternative with high diagnostic performance in the evaluation of hypermetabolic bone lesions to diagnose bone tumors and tumor-like lesions.

How Effective Are Noninvasive Tests for Diagnosing Malignant Peripheral Nerve Sheath Tumors in Patients with Neurofibromatosis Type 1? Diagnosing MPNST in NF1 Patients

Background

Distinguishing between benign and malignant peripheral nerve sheath tumors (MPNSTs) in neurofibromatosis 1 (NF1) patients prior to excision can be challenging. How can MPNST be most accurately diagnosed using clinical symptoms, magnetic resonance imaging (MRI) findings (tumor size, depth, and necrosis), positron emission tomography (PET) measures (SUV_peak, SUV_max, SUV_{max tumor}/SUV_{mean liver}, and qualitative scale), and combinations of the above? Methods. All NF1 patients who underwent PET imaging at our institution (January 1, 2007–December 31, 2016) were included. Medical records were reviewed for clinical findings; MR images and PET images were interpreted by two fellowship-trained musculoskeletal and nuclear medicine radiologists, respectively. Receiver operating characteristic (ROC) curves were created for each PET measurement; the area under the curve (AUC) and thresholds for diagnosing malignancy were calculated. Logistic regression determined significant predictors of malignancy.

Results

Our population of 41 patients contained 34 benign and 36 malignant tumors. Clinical findings did not reliably predict MPNST. Tumor depth below fascia was highly sensitive; larger tumors were more likely to be malignant but without a useful cutoff for diagnosis. Necrosis on MRI was highly accurate and was the only significant variable in the regression model. PET measures were highly accurate, with AUCs comparable and cutoff points consistent with prior studies. A diagnostic algorithm was created using MRI and PET findings.

Conclusions

MRI and PET were more effective at diagnosing MPNST than clinical features. We created an algorithm for preoperative evaluation of peripheral nerve sheath tumors in NF1 patients, for which additional validation will be indicated.

Detection of additional primary malignancies: the role of CT and PET/CT combined with multiple percutaneous biopsy

Objective

To evaluate the imaging findings of ¹⁸F-fluorodeoxyglucose positron emission tomography/computed tomography (¹⁸F-FDG PET/CT) and computed tomography (CT) in patients with additional primary tumors, correlating the results with those of the method used in order to elucidate the diagnosis and of the pathology reports.

Materials and Methods

We retrospectively analyzed the medical records, pathology reports and images of 11 patients who underwent CT, ¹⁸F-FDG PET/CT, or both. We included patients with at least two tumors, with confirmed distinct histopathological profiles, at different sites. Patients in whom there was no diagnostic confirmation were excluded, as were those in whom the additional lesion was suspected of being a metastasis of the first.

Results

New primary malignancies were identified in 11 patients, one new tumor being found in 10 and two new tumors being found in 1. The confirmed sites of the additional malignancies were the lung, kidney, prostate, jejunum, and breast. Single or multiple percutaneous biopsies were performed in 10 patients, and 1 patient underwent a surgical procedure for diagnostic and therapeutic purposes. The tumors were metachronous in 6 cases and synchronous in 5.

Conclusion

CT and ¹⁸F-FDG PET-CT combined with multiple percutaneous biopsy could facilitate the diagnosis of additional lesions, thus optimizing the treatment and follow-up of the affected patients.

Cost-effectiveness of second-line diagnostic investigations in patients included in the DANTE trial: a randomized controlled trial of lung cancer screening with low-dose computed tomography

AIM

The aim of this study was to analyze the economic efficiency of second-line diagnostic investigations in patients with undetermined lung nodules.

PARTICIPANTS AND METHODS

A retrospective review of all surgical cases included in the DANTE trial from 2001 to 2006 for lung cancer screening was performed. Overall, 217 patients and 261 lung nodules were analyzed. The cohort was divided into patients investigated with PET and/or computed tomography (CT)-guided biopsy (PET-CTB protocol; N=100), compared with those assessed with serial low-dose CT scans (standard protocol; N=161). Outpatient's and inpatient's costs were expressed in euros and derived from the Italian National Health Service. Ineffective costs were defined as the cost of procedures that lead to avoidable surgical intervention.

RESULTS

The diagnostic accuracy of the two protocols was 91% for the standard (sensitivity 100%, specificity 91%, positive predictive value 26%, and negative predictive value 100%) and 90% for the PET-CTB protocol (sensitivity 98%, specificity 81%, positive predictive value 85%, and negative predictive value 97%). Average costs for outpatient's diagnostics were 694 and 1.462 euros, respectively, for the standard and PET-CTB protocol. Average inpatient's costs for both protocols were 12.121 euros. The two protocols showed comparable effectiveness in terms of outpatient's costs (94 and 90%, respectively; P=0.252). Inpatient's costs were effective in 36% of cases monitored according to the standard protocol compared with 85% of patients investigated with PET-CTB protocol. Ineffective costs corresponded to 64 and 15%, respectively (P<0.0001).

CONCLUSION

Despite a higher average cost for outpatient's diagnostics, the implementation of PET imaging with or without CT-guided needle biopsy in the workup of suspicious lung nodules results in reduced unnecessary harm and costs related to inpatient's procedures.

Diagnostic performance of real-time robotic arm-assisted 18F-FDG PET/CT-guided percutaneous biopsy in metabolically active abdominal and pelvic lesions

PURPOSE

To evaluate the feasibility and diagnostic performance of ¹⁸F-FDG PET/CT-guided biopsy of abdominal and pelvic lesions with automated robotic arm (ARA) assistance.

METHODS

This prospective study included 114 patients (75 men, 39 women; mean age 51.3 ± 14.7 years, range: 18-90 years) who underwent PET/CT-guided biopsy of FDG-avid abdominal and pelvic lesions from October 2014 to December 2017. Of these patients, 54 had a prior inconclusive CT-guided biopsy. The biopsies were done with ARA assistance, and a real-time sample was obtained after confirming the position of the needle tip within the target lesion on PET/CT. Histopathology reports were reviewed to evaluate the diagnostic performance of the procedure. Clinical or imaging follow-up was done to confirm negative results.

RESULTS

The lesions were successfully targeted in 110 of the 114 patients (96.5%) and yielded a pathological diagnosis. Pathological diagnoses were confirmed in 50 of the 54 patients with a prior inconclusive biopsy. Of the 110 lesions, 82 were malignant, 20 were benign, and 8 showed minimal residual FDG uptake at the end of treatment and had no active disease even on clinical and imaging follow-up of at least 3 months. Findings were true-positive in 102 lesions, false-positive in none, true-negative in eight and false-negative in four. The procedure showed sensitivity, specificity, positive predictive value, negative predictive value and accuracy of 96.2%, 100%, 100%, 66.7 and 96.5%, respectively. No immediate complications or delayed life-threatening events were observed.

CONCLUSION

Percutaneous biopsy of metabolically active abdominal and pelvic lesions with ARA assistance is a technically feasible, safe and accurate method for pathological diagnosis with high diagnostic performance. PET-guided biopsy is highly practical and useful in patients, especially in those with a previous inconclusive biopsy.