Morphological Imaging Methods Research Articles

Special stereotactic radiotherapy techniques: procedures and equipment for treatment simulation and dose delivery.

Stereotactic radiotherapy (SRT ) is a multi-step procedure with each step requiring extreme accuracy. Physician-dependent accuracy includes appropriate disease staging, multi-disciplinary discussion with shared decision-making, choice of morphological and functional imaging methods to identify and delineate the tumor target and organs at risk, an image-guided patient set-up, active or passive management of intra-fraction movement, clinical and instrumental follow-up. Medical physicist-dependent accuracy includes use of advanced software for treatment planning and more advanced Quality Assurance procedures than required for conventional radiotherapy. Consequently, all the professionals require appropriate training in skills for high-quality SRT.Thanks to the technological advances, SRT has moved from a “frame-based” technique, i.e. the use of stereotactic coordinates which are identified by means of rigid localization frames, to the modern “frame-less” SRT which localizes the target volume directly, or by means of anatomical surrogates or fiducial markers that have previously been placed within or near the target. This review describes all the SRT steps in depth, from target simulation and delineation procedures to treatment delivery and image-guided radiation therapy. Target movement assessment and management are also described.

Positron emission tomography/computed tomography (PET/CT) in multiple myeloma

Imaging plays apivotal role in the management of multiple myeloma (MM). Besides morphological imaging methods, such as whole-body X‑ray, computed tomography (CT) and magnetic resonance imaging (MRI), the hybrid modality positron emission tomography/CT (PET/CT) using the glucose analogue 18F‑fluorodeoxyglucose (18F‑FDG) as radiotracer is increasingly used. Aim of this review article is to outline the major applications of PET/CT in the diagnosis and management of MM, and to provide hints on the reading and interpretation. Background knowledge and guideline recommendations on imaging of MM are outlined and complemented by recent study results. Although 18F‑FDG PET/CT is not currently considered astandard method for the diagnosis of MM, it is avery powerful diagnostic tool for the detection of medullary and extramedullary disease, areliable predictor of survival and the most robust modality for treatment response evaluation. Moreover, it plays a significant role in minimal residual disease (MRD) assessment. On the other hand, practical considerations on local availability and costs limit the widespread use of PET/CT. In addition, false-negative and the seldom false-positive results and the heterogeneity of MM presentation inevitably make interpretation of PET/CT images challenging. PET/CT has ahigh value in the diagnosis, prognosis, and assessment of treatment response in patients with MM. Therefore, the role of the modality in the management of the disease is expected to increase in the near future.

Update Regarding Imaging of Neuroendocrine Neoplasms.

Neuroendocrine neoplasms (NEN) are a heterogeneous group of tumors characterized by the expression of typical proteins. A wide range of morphological and functional imaging methods is required in order to adequately assess the course of the disease and to optimally treat the patient. The spectrum of indications ranges from the detection of small primary tumors to the documentation of the metastasis pattern and the assessment of the suitability for certain invasive or noninvasive therapy methods. The exact recording and quantification of findings is indispensable. This article is based on a comprehensive literature search on the different aspects of neuroendocrine neoplasm imaging. This article is intended to provide an overview of the available imaging procedures with their respective advantages and disadvantages for diagnostics and their value for the follow-up of neuroendocrine neoplasms. Recommendations for examination protocols, typical image findings, and an outlook regarding future developments are presented. · Neuroendocrine neoplasms are relatively rare and represent a complex and multiform disease group. Even in metastatic disease, long-term progression-free survival is not uncommon.. · Diagnostics in neuroendocrine neoplasms use a wide range of complementary morphological and functional imaging methods.. · Adequate selection of the imaging method, examination planning and preparation of the patient are essential for exact staging and reliable follow-up.. · Figiel JH, Viniol SG, Görlach J et al. Update Regarding Imaging of Neuroendocrine Neoplasms. Fortschr Röntgenstr 2020; 192: 171 - 182.

Clinical value of 99mTc-HYNIC-TOC SPECT/CT for the diagnosis primary small cell neuroendocrine carcinomas of the nasal cavity and paranasal sinuses

PurposeTo evaluate the diagnostic value of 99mTc-HYNIC-TOC SPECT/CT in the detection of primary small cell neuroendocrine carcinomas of the nasal cavity and paranasal sinuses. MethodsFrom September 2005 to November 2015, 19 patients (mean age 53.9 years, range 37–77; male 6, female 13) with sinonasal small cell neuroendocrine carcinoma (SNEC) underwent whole-body 99mTc-HYNIC-TOC SPECT/CT scan. ResultsAll 19 primary lesions were detected by 99mTc-HYNIC-TOC SPECT/CT. A total of 212 metastatic lesions were identified by organ-based analysis, and the sensitivity and specificity of 99mTc-HYNIC-TOC SPECT/CT were 90.5% and 92.3%, respectively. The application of 99mTc-HYNIC-TOC SPECT/CT resulted in the detection of a higher number of lesions in 11 patients (57.9%) and in the successful alteration of the treatment in 7 patients (36.8%) compared with the morphological imaging methods. Conclusion99mTc-HYNIC-TOC scintigraphy is an effective method for the detection of the sinonasal SNEC.

Current diagnostic imaging of pheochromocytomas and implications for therapeutic strategy.

The topic of pheochromocytomas is becoming increasingly popular as a result of major advances in different medical fields, including laboratory diagnosis, genetics, therapy, and particularly in novel advances in imaging techniques. The present review article discusses current clinical, biochemical, genetic and histopathological aspects of the diagnosis of pheochromocytomas and planning of pre-surgical preparation and subsequent surgical treatment options. The main part of the paper is focused on the role of morphological imaging methods (primarily computed tomography and magnetic resonance imaging) and functional imaging (scintigraphy and positron emission tomography) in the diagnosis and staging of pheochromocytomas.

Methods of anatomical and metabolic imaging in head and neck region tumors

The incidence of head and neck cancer (HNC) ranges from 5.5% to 6.2% of general cancer incidence in Poland as well as in other European countries and in the US. Precise evaluation of the clinical stage in this group of patients allows for personalized treatment, inter alia , to choose proper surgery technique, to plan and verify radiation therapy. It is a result of availability of wide spectrum of imaging methods currently used in oncology. These methods are also used in the suitable assessment of antineoplastic therapy effects, which gives the chance of early detection of cancer progression. Methods of imaging diagnostics — anatomical and metabolic — differ in terms of sensitivity, specificity and diagnostic accuracy. Each of them has advantages and disadvantages in imaging of HNC, hence, choice of treatment method should not be made based on single imaging modality. Increasingly, information obtained from alternative imaging studies support optimal decision in everyday clinical practice. This review describes clinical usefulness of currently available morphological and metabolic imaging methods in HNC patients, with particular emphasis on innovative technologies, like PET/MR hybrid.

Research progress in metabolic and receptor-like nuclear imaging agents for hepatocellular carcinoma

Hepatocellular carcinoma (HCC) commonly presents with high morbidity and mortality, and early staging diagnosis and timely treatment is pivotal to prolonging patients' survival time. Compared with traditional morphological imaging methods such as ultrasound, computed tomography (CT), and magnetic resonance imaging (MRI), functional imaging methods like single-photon emission computed tomography (SPECT) and positron emission tomography (PET) are playing an increasingly important role in the early diagnosis, efficacy assessment, prognostic evaluation, and treatment planning for HCC, thanks to their higher sensitivity at a molecular level by using various radiopharmaceuticals.

Structural-functional lung imaging using a combined CT-EIT and a Discrete Cosine Transformation reconstruction method.

Lung EIT is a functional imaging method that utilizes electrical currents to reconstruct images of conductivity changes inside the thorax. This technique is radiation free and applicable at the bedside, but lacks of spatial resolution compared to morphological imaging methods such as X-ray computed tomography (CT). In this article we describe an approach for EIT image reconstruction using morphologic information obtained from other structural imaging modalities. This leads to recon- structed images of lung ventilation that can easily be superimposed with structural CT or MRI images, which facilitates image interpretation. The approach is based on a Discrete Cosine Transformation (DCT) of an image of the considered transversal thorax slice. The use of DCT enables reduction of the dimensionality of the reconstruction and ensures that only conductivity changes of the lungs are reconstructed and displayed. The DCT based approach is well suited to fuse morphological image information with functional lung imaging at low computational costs. Results on simulated data indicate that this approach preserves the morphological structures of the lungs and avoids blurring of the solution. Images from patient measurements reveal the capabilities of the method and demonstrate benefits in possible applications.

Imaging Advances for Target Volume Definition in Radiotherapy

Imaging remains the foundation for any radiotherapy (RT). In this article, we will briefly review the rationale of multimodality imaging for target volume definition in RT treatment planning and outline the development of novel RT strategies using new sophisticated RT planning techniques that aim to improve the therapeutic ratio of RT. We will address the current limitations using morphological imaging methods for radical RT. We will review the use of functional imaging to provide biological information that may permit the design of biological based targets that may address the issues of radioresistance such hypoxia and accelerated tumour repopulation as well as the current applications for these methods and their limitations for its utilisation in current RT programmes.

Clinical value of [18F]FDG-PET/CT in the detection of metastatic medullary thyroid cancer

PurposeTo evaluate the value of fluorine-18 2-deoxy-2-d-glucose positron emission tomography/computed tomography ([18F]FDG-PET/CT) in the detection of metastatic medullary thyroid cancer. MethodsFrom November 2006 to November 2012, 50 medullary thyroid cancer patients (median age 48.7years, range 18–76) who had a total thyroidectomy operation underwent whole-body [18F]FDG-PET/CT scans. The diagnostic accuracy of [18F]FDG-PET/CT was determined through both lesion-based and patient-based analyses. Further pathological tests were performed on all identified lesions or clinically followed for a minimum period of 6months. ResultsOne hundred forty-four suspicious lesions were identified by organ-based analysis. Of these lesions, [18F]FDG-PET/CT detected 99 true-positive lesions, sensitivity was 73.3%, and specificity was 66.7%. On the patient-based analysis, the overall sensitivity and specificity were calculated as 65.7% and 92.3%, respectively. Using a cutoff calcitonin value of 1000pg/ml, in patients with calcitonin lower than this value, sensitivity and specificity were 42.9% and 91.0%, respectively. In patients with calcitonin exceeding this value, they raised to 77.3% (χ2=4.392, P<.05) and 100% (χ2=0.197, P>.05), respectively. Compared with conventional imaging modality, PET/CT scans detected more lesions in 10 patients (20.4%) and correctly changed the treatment in 8 patients (16.3%). Conclusion[18F]FDG-PET/CT has excellent sensitivity and specificity, especially when the calcitonin value is higher than 1000pg/ml for detecting metastatic medullary thyroid cancer. Compared to conventional morphologic imaging methods, it provides additional information for diagnosis.

Depicting Medullary Thyroid Cancer Recurrence: The Past and the Future of Nuclear Medicine Imaging

Context:Inherited and sporadic medullary thyroid cancer (MTC) is an uncommon and medically challenging malignancy. Even if the extent of initial surgery is deemed adequate, the recurrence rate remains high, up to 50% in most series. Measurement of serum calcitonin is important in the follow-up of patients with MTC, and reliably reflects the existence of the disease.Evidence Acquisition:There is no single sensitive diagnostic imaging method to reveal all MTC recurrences or metastases. Conventional morphologic imaging methods (U/S, CT, and MRI) and several methods of nuclear medicine have been used for this purpose with variable accuracy.Results:The main role of nuclear medicine imaging is the detection of residual or recurrent tumor in the postoperative follow-up. In this review we present the radiopharmaceuticals used in the diagnosis of MTC recurrence, and comparison among them.Conclusions:The most used radiopharmaceuticals labelled with γ emitters are: Metaiodobenzylguanidine (MIBG), labelled with 131I or 123I, 111In-pentetreotide (Octreoscan), 99mTc-pentavalent dimercaptosuccinic acid (99mTc(V)-DMSA), and 99mTc-EDDA/HYNIC-Tyr3-Octreotide ( Tektrotyd). The radiopharmaceuticals labelled with a positron-emitting radionuclide (β+), suitable for positron emission tomography (PET) imaging are: 18F-fluorodeoxyglucose (18F-FDG), 18F-fluorodihydroxyphenylalanine (18F-DOPA), and 68Ga-labelled somatostatin analogues (68Ga-DOTATATE or DOTATOC).

Discrepancies and priorities in staging and restaging malignant lymphoma by SPET, SPET/CT, PET/CT and PET/MRI.

Due to the rapid development of modern imaging methods and also of medical oncology, there has been a significant progress in diagnosis and treatment of malignant lymphomas in the last few years. Nuclear medicine (NM) imaging methods gained new perspectives via the so called hybrid technologies-single-photon emission tomography combined with computed tomography (SPET/CT), positron emission tomography combined with computed tomography (PET/CT) and recently even positron emission tomography combined with magnetic resonance imaging (PET/MRI), which have led to a better image quality and diagnostic findings. Since SPET/CT evolved later than the "gold standard" 18F-FDG-PET/CT in lymphoma diagnostics, there are fewer studies with it, but it seems to be an excellent alternative to PET/CT. The role of PET/CT is confirmed up-to-date for typically 18F-FDG-avid lymphomas, in staging and restaging diffuse large B-cell and some aggressive follicular lymphomas, in a suspected relapse of treatment of both Hodgkin's and non-Hodgkin's lymphomas. There are many discussions about the "interim-PET" but the recent results indicate its important prognostic role for predicting disease-free survival and the possibility to modify treatment intensity in order to reduce late side effects. On the other hand, the routine and approbated use of conventional morphologic imaging methods CT and MRI serve as a "reference standard" for the newer hybrid technologies not only in diagnostics but also in the cost-benefit ratio analysis and remain the basic imaging modalities when hybrid methods are not available. In conclusion, our review points at the main advantages and disadvantages of each NM method mentioned above in the diagnosis and follow-up of malignant lymphomas. Specifically, problems in differential diagnostics and further possibilities to better optimize the diagnostic and therapeutic algorithm are mentioned.

Gastroenteropancreatic Neuroendocrine Tumors: Role of Imaging in Diagnosis and Management

Gastroenteropancreatic neuroendocrine tumors (GEP-NETs) are a heterogeneous group of neoplasms that arise from cells of the diffuse neuroendocrine system and are characterized by a wide spectrum of clinical manifestations. All NETs are potentially malignant but differ in their biologic characteristics and the probability of metastatic disease. The pathologic classification of these tumors relies on their proliferation and differentiation. In the past decades, several nomenclatures have been proposed to stratify neuroendocrine tumors, but the World Health Organization classification is the one that is most widely accepted and used. The diagnosis of neuroendocrine tumor relies on clinical manifestation, laboratory parameters, imaging features, and tissue biomarkers in a biopsy specimen. With improved understanding of the natural history and lesion biology, management of GEP-NETs has also evolved. Although surgery remains the only potentially curative therapy for patients with primary GEP-NETs, other available treatments include chemotherapy, interferon, somatostatin analogs, and targeted therapies. Recent improvements in both morphologic and functional imaging methods have contributed immensely to patient care. Morphologic imaging with contrast agent-enhanced multidetector computed tomography and magnetic resonance imaging is most widely used for initial evaluation and staging of disease in these patients, whereas functional imaging techniques are useful both for detection and prognostic evaluation and can change treatment planning.

Imaging of neuroendocrine tumors

The imaging needs in the individual neuroendocrine tumor (NET) patient are very diverse and the choice of method, or combination of techniques, depends on the characteristics of the particular type of NET and its presentation. The various morphological and functional imaging methods and important methodological aspects are described. The imaging requirements for the various NET subtypes are explained and typical NET image findings are described and illustrated. The choice of the optimum imaging techniques is not only a matter of sensitivity and specificity but must also be considered in the light of the local availability and expertise in the department. Familiarity with contrast-enhancement technique for computed tomography (CT) and magnetic resonance imaging (MRI) is important in the interpretation and understanding of the imaging results. MRI including diffusion weighted imaging (DWI) for oncological imaging has been reported to improve tumor visualization and reader confidence and is expected to similarly be beneficial for NET imaging. Positron emission tomography (PET) using 68Ga-labeled somatostatin analogs is in several aspects superior to somatostatin receptor scintigraphy using Octreoscan®. Molecular imaging problem-solving tools, when PET/CT using 68Ga-labeled somatostatin analogs fails, are PET/CT with 11C-5-HTP and 18F-DOPA.

Correlation between Calcitonin Levels and [F18]FDG-PET/CT in the Detection of Recurrence in Patients with Sporadic and Hereditary Medullary Thyroid Cancer

Purpose. Measurement of serum calcitonin is important in the followup of patients with medullary thyroid carcinoma (MTC) and reliably reflects the presence of the disease. This is the largest study so far in bibliography investigating the diagnostic accuracy of combined [18F]FDG-PET/CT in patients with MTC and elevated calcitonin levels. Methods. Between February 2007 and February 2011, 59 [18F]FDG-PET/CT were performed on 51 patients with MTC and elevated calcitonin levels for localization of recurrent disease. Conventional morphologic imaging methods were negative or showed equivocal findings. Results. Among the 59 [18F]FDG-PET/CT, 29 were positive (26 had true-positive and 3 false-positive findings) and 30 negative. The overall per-patient sensitivity of [18F]FDG-PET/CT was 44.1%. Using as cut-off point the calcitonin value of 1000 pg/ml, in patients with calcitonin exceeding this value, sensitivity raised to 86.7%. The overall sensitivity of [18F]FDG-PET/CT was lower (23%) in patients with MEN IIA syndrome. Conclusion. The findings of this paper show that [18F]FDG-PET/CT is valuable for the detection of recurrence in patients with highly elevated calcitonin levels, >1000 pg/mL, but in patients with lower calcitonin levels, its contribution is questionable. Also, there is evidence that the sensitivity of [18F]FDG-PET/CT is lower in patients with MTC as part of MEN IIA syndrome.

Imageries et traitements basés sur les récepteurs à la somatostatine dans les tumeurs endocrines digestives

The management of gastroenteropancreatic endocrine tumors is greatly linked to the localization of primary tumor. Morphological imaging methods are thus necessary. However, the expression of somatostatin receptors in endocrine tumors makes their detection possible thanks to radiolabeled somastotatin analogs. [ 111In-DTPA] octreotide is the main radiolabeled analog for somatostatin receptor scintigraphy. Positron emission tomography uses other tracers and currently allows improvement of the diagnosis and the tumoral staging. It also allows to affect the therapeutic management. A further step is about to be taken as far as the therapy of endocrine tumors is concerned with the peptide receptor radionuclide therapy. Those therapies are now being offered in some European and American centers for progressive metastatic tumors. Their place in the therapeutic strategy has to be defined, especially in comparison to targeted therapy. The sudden and delayed adverse events as well as the current legislation on the use of radioactive therapy-aimed products have limited their development in France so far.

Radionuclide and hybrid imaging of recurrent prostate cancer

Prostate cancer is one of the most common cancers in men, leading to substantial morbidity and mortality. After definitive therapy with surgery or radiation, many patients have biochemical relapse of disease--ie, an increase in their prostate-specific antigen level--which often precedes clinically apparent disease by months or even years. Therefore, imaging of the site and extent of tumour recurrence (local, regional, distant, or a combination) is of great interest. Conventional morphological imaging methods showed limited accuracy for assessment of recurrent prostate cancer; however, in recent years, functional and molecular imaging have offered the possibility of imaging molecular or cellular processes of individual tumours, often with more accuracy than morphological imaging. Hybrid imaging modalities (PET-CT, and single-photon emission CT [SPECT]-CT) have been introduced that combine functional and morphological data and allow whole-body imaging. Here, we review the contribution of radionuclide imaging and hybrid imaging for assessment of recurrent prostate cancer (local vs regional vs distant disease). We discuss available data on PET-CT and SPECT-CT, and provide an overview of experimental tracers and their preclinical and clinical development. Finally, we present a perspective on the potential of future hybrid magnetic resonance-PET imaging.

586 IMAGING OF NEUROENDOCRINE TUMORS AND LIVER METASTASIS BY F18-DOPA PET SCANNING

Introdction: In patients with neuroendocrine tumors it is important to accurately diagnose tumor localization and metastases, biochemical activity, and progression. The initial workup for NET patients consists of morphological imaging methods by CT/MRI, combined with functional whole-body imaging with somatostatin-receptor scintigraphy (SRS). However, there may be difficulties for CT and MRI to separate tumors and mesenterial metastases from intestinal structures. Furthermore, SRS can produce false-negative findings, because of the variable affinity and expression of somatostatin receptors and the restricted resolution of gamma cameras and single-photon-emission tomography (SPECT) methods. Methods: A new imaging method for neuroendocrine tumors using PET and the catecholamine precursor 6-[fluoride-18]fluorolevodopa (18F-DOPA) has been developed. 18F-DOPA PETscanning is a metabolic scanning while SRS scanning depends on the presence of somatostatin receptors on NET cancer cells. We used 18F-DOPA PET scan and SRS in 15 patienst with known or suspected NET. Results: F18-DOPA PET scan was able to detect primary tumors not demonstrated by SRS scintigraphy. Further, 18F-DOPA PET was able to detect more metatatasis in the liver and extrahepatic tissues comparedf to conventional SRS imaging. Conclusion: F18-DOPA PET scanning demonstrated more tumors in more regions compared to the conventional imaging modalities in NET patients. The combination of this specific PET tracer with the high resolution provided by PET was clinically relevant with improvement in the detection and staging of neuroendocrine tumors. In several patients this has clinical impact on patient handling with a change in treatment modality.

P.133 DIAGNOSTIC VALUE OF LENS CULINARIS AGGLUTININ ISOFORM 3 FRACTION (AFP-L3%) AND DES-GAMMA-CARBOXY PROTHROMBIN (DCP) FOR THE DIAGNOSIS OF HCC IN CIRRHOTIC PATIENTS

Introdction: In patients with neuroendocrine tumors it is important to accurately diagnose tumor localization and metastases, biochemical activity, and progression. The initial workup for NET patients consists of morphological imaging methods by CT/MRI, combined with functional whole-body imaging with somatostatin-receptor scintigraphy (SRS). However, there may be difficulties for CT and MRI to separate tumors and mesenterial metastases from intestinal structures. Furthermore, SRS can produce false-negative findings, because of the variable affinity and expression of somatostatin receptors and the restricted resolution of gamma cameras and single-photon-emission tomography (SPECT) methods. Methods: A new imaging method for neuroendocrine tumors using PET and the catecholamine precursor 6-[fluoride-18]fluorolevodopa (18F-DOPA) has been developed. 18F-DOPA PETscanning is a metabolic scanning while SRS scanning depends on the presence of somatostatin receptors on NET cancer cells. We used 18F-DOPA PET scan and SRS in 15 patienst with known or suspected NET. Results: F18-DOPA PET scan was able to detect primary tumors not demonstrated by SRS scintigraphy. Further, 18F-DOPA PET was able to detect more metatatasis in the liver and extrahepatic tissues comparedf to conventional SRS imaging. Conclusion: F18-DOPA PET scanning demonstrated more tumors in more regions compared to the conventional imaging modalities in NET patients. The combination of this specific PET tracer with the high resolution provided by PET was clinically relevant with improvement in the detection and staging of neuroendocrine tumors. In several patients this has clinical impact on patient handling with a change in treatment modality.

Imaging procedures for gastrointestinal stromal tumors

Morphological and functional imaging methods are used for staging of gastrointestinal stromal tumors (GIST) and to follow-up GIST patients undergoing therapy. Computed tomography is the most frequently used morphological imaging procedure and has been recommended as the imaging method of choice according to current GIST guidelines. However, positron emission tomography using [(18)F]-2-fluoro-2-deoxy-D-glucose (FDG-PET) as the radiotracer has shown to be advantageous over morphological imaging procedures when assessing therapy response at an early time point. While tumor size reduction in morphological imaging typically requires time to develop, a decrease in FDG uptake can be detected as early as 24 h following therapy initiation. To overcome the limitations of size-based therapy response assessment on morphological imaging procedures, new density-based therapy response criteria have been developed and implemented for GIST. This review addresses both indications and accuracy of morphological and functional imaging modalities for GIST.