Positron emission tomography and magnetic resonance imaging combined with computed tomography in tumor volume delineation: A case report

BACKGROUND Accurate delineation of the target area for patients with hypopharyngeal cancer is the key to achieving an ideal radiotherapy effect.Since computed tomography(CT)alone can no longer meet the treatment needs,fusing CT images with magnetic resonance imaging(MRI)or positron emission tomography(PET)images can overcome the disadvantages of CT.Herein,we present a clinical case of hypopharyngeal cancer to delineate the tumor volume using combined MRI-CT and PET-CT fusion images to examine if they could accurately cover the tumor volume.CASE SUMMARY A 67-year-old male patient with hypopharyngeal carcinoma could not tolerate chemotherapy and surgery due to complicated health issues such as diabetic nephropathy and other underlying diseases.After multidisciplinary consultations,clinicians eventually agreed to undergo radiotherapy to control the progression of his tumor.He was examined by CT,MRI,and 18-fluorodeoxyglucose-PET for treatment planning,and CT images were fused with PET and MRI images while delineating tumor volume.CONCLUSION The image fusion of MRI-CT and PET-CT has both advantages and disadvantages.Compared with CT images alone,the combination of MRI-CT and PET-CT fusion images can precisely cover the gross tumor volume in hypopharyngeal carcinoma and avoid overestimation or incomplete coverage of tumor volume.

Computed tomography, magnetic resonance imaging, and Fdeoxyglucose positron emission computed tomography/computed tomography findings of alveolar soft part sarcoma with calcification in the thigh: A case report

BACKGROUND Alveolar soft part sarcoma(ASPS)is an extremely rare malignant sarcoma,accounting for less than 1%of all soft-tissue sarcomas.However,limited information is available on multimodal imaging[computed tomography(CT),magnetic resonance imaging(MRI),and positron emission computed tomography/computed tomography(PET/CT)]of ASPS.CASE SUMMARY This study reports a case of a 35-year-old female patient with ASPS of the left thigh with lung metastasis.The patient presented with a 1-year history of a palpable mass in the lower extremity,which exhibited rapid growth for 3 wk.CT,MRI,and F-deoxyglucose PET/CT examinations were performed.CT showed a slightly hypodense or isodense mass with patchy calcifications.On MRI examination,the mass manifested hyperintensity on T1-weighted,T2-weighted,and diffusion-weighted images with some signal voids.PET/CT images demonstrated an intensely hypermetabolic mass in the left thigh and hypermetabolic nodules in lungs.CONCLUSION ASPS should be considered as a possible diagnosis when a slow-growing mass is detected in the soft tissue of the extremities,with hyperintensity and numerous signal voids on T1-weighted,T2-weighted,and diffusion-weighted images and intense F-deoxyglucose uptake on PET/CT.ASPS can have calcifications on CT.

ASSESSMENT OF MYOCARDIAL VIABILITY WITH CONTRAST-ENHANCED MAGNETIC RESONANCE IMAGING AND COMPARISON WITH SINGLE-PHOTON EMISSION COMPUTED TOMOGRAPHY

Objective To compare contrast-enhanced magnetic resonance imaging （ceMRI） with nuclear metabolic imaging for the assessment of myocardial viability in patients with chronic ischemic heart disease. Methods Twenty patients with suspected chronic ischemic heart disease underwent ceMRI and technetium-99m sestamibi single-photon emission computed tomography （SPECT）. Patients with positive SPECT results also underwent 18 F-fluorodeoxyglucose （FDG） SPECT. In a 17-segment model, the segmental extent of hyperenhancement （SEH） by ceMRI was compared with segmental FDG and sestamibi uptake by SPECT. Correlation between the extent of hyperenhancement by ceMRI and left ventricular function was analyzed. Seven patients got negative results both in ceMRI and technetium-99m sestamibi SPECT. The rest 13 patients with positive results then underwent ^18F-FDG SPECT. In 221 segments of 13 patients, SEH was （2. 1±8.2）%, （25.0±13.7 ）%, and （57. 7±23.6 ）% in segments with normal metabolism/perfusion, metabolism/perfusion mismatch, and matched defects, respectively, and there were significant differences between either two of them （ all P 〈 0.05）. By receiver operating characteristic curve analysis, the area under the curve was 0. 95 for the differentiation between viable and non-viable segments. At the cutoff value of 34%, SEH optimally differentiated viable from non-viable segments defined by SPECT. Using this threshold, the sensitivity and specificity of ceMRI to detect non-viable myocardium as defined by SPECT were 92% and 93%, respectively. Hyperenhancement size by ceMRI was correlated negatively with the left ventricular ejection fraction （ r = - 0.90, P 〈 0.01 ） and positively with left ventricular volumes （ r = 0. 62 for end-diastolic volume, r = 0.75 for end-systolic volume, both P 〈 0.05 ）. Conclusion CeMRI allows assessment of myocardial viability with a high accuracy in patients with chronic ischemic heart disease.

Utility of positron emission tomography-magnetic resonance imaging in musculoskeletal imaging

Differentiation between neoplastic and nonneoplastic conditions magnetic resonance imaging(MRI) has established itself as one of the key clinical tools in evaluation of musculoskeletal pathology. However, MRI still has several key limitations which require supplemental information from additional modalities to complete evaluation of various disorders. This has led to the development hybrid positron emission tomography(PET)-MRI which is rapidly evolving to address key clinical questions by using the morphological strengths of MRI and functional information of PET imaging. In this article, we aim to review physical principles and techniques of PET-MRI and discuss clinical utility of functional information obtained from PET imaging and structural information obtained from MRI imaging for the evaluation of musculoskeletal pathology. More specifically, this review highlights the role of PET-MRI in musculoskeletal oncology including initial diagnosis and staging, treatment planning and posttreatment follow-up. Also we will review utility of PET-MRI in evaluating musculoskeletal infections(especially in the immunocompromised and diabetics) and inflammatory condition. Additionally, common pitfalls of PET-MRI will be addressed.

Liver metastases:Contrast-enhanced ultrasound compared with computed tomography and magnetic resonance

The development of ultrasound contrast agents with excellent tolerance and safety profiles has notably improved liver evaluation with ultrasound(US)for several applications,especially for the detection of metastases.In particular,contrast enhanced ultrasonography(CEUS)allows the display of the parenchymal microvasculature,enabling the study and visualization of the enhancement patterns of liver lesions in real time and in a continuous manner in all vascular phases,which is similar to contrast-enhanced computed tomography(CT)and contrast-enhanced magnetic resonance imaging.Clinical studies have reported that the use of a contrast agent enables the visualization of more metastases with significantly improved sensitivity and specificity compared to baseline-US.Furthermore,studies have shown that CEUS yields sensitivities comparable to CT.In this review,we describe the state of the art of CEUS for detecting colorectal liver metastases,the imaging features,the literature reports of metastases in CEUS as well as its technique,its clinical role and its potential applications.Additionally,the updated international consensus panel guidelines are reported in this review with the inherent limitations of this technique and best practice experiences.

Limited brain magnetic resonance imaging for evaluation of non-traumatic pediatric head emergencies

Limited brain magnetic resonance imaging(MRI) consisting of axial fluid attenuated inversion recovery, axial diffusion weighted imaging, coronal single shot fast spin echo(SSFSE) and sagittal SSFSE can be performed in under 5 min of scan time. This approach may provide more information than a non-contrast head computed tomography(CT) in non-traumatic pediatric head emergency, avoid ionizing radiation from CT scan and stratify patients who need more detailed brain MRI. Research studies are required to provide evidence for feasibility of such an approach.

Role of advanced magnetic resonance imaging in the assessment of malignancies of the mediastinum

In the new era of functional magnetic resonance imaging(MRI), the utility of chest MRI is increasing exponentially due to several advances, including absence of ionizing radiation, excellent tissue contrast and high capability for lesion characterization and treatment monitoring. The application of several of these diagnostic weapons in a multiparametric fashion enables to better characterize thymic epithelial tumors and other mediastinal tumoral lesions, accurate assessment of the invasion of adjacent structures and detection of pathologic lymph nodes and metastasis. Also, "do not touch lesions" could be identified with the associated impact in the management of those patients. One of the hotspots of the multiparametric chest MR is its ability to detect with acuity early response to treatment in patients with mediastinal malignant neoplasms. This has been related with higher rates of overall survival and progression free survival.Therefore, in this review we will analyze the current functional imaging techniques available(18 F-Fluorodeoxiglucose positron emission tomography/computed tomography, diffusion-weighted imaging, dynamic contrast-enhanced MRI, diffusion tensor imaging and MR spectroscopy) for the evaluation of mediastinal lesions, with a focus in their correct acquisition and post-processing. Also, to review the clinical applications of these techniques in the diagnostic approach of benign and malignant conditions of the mediastinum.

Clinical significance of prostate 18F-labelled fluorodeoxyglucose uptake on positron emission tomography/computed tomography:A five-year review

AIM To determine the significance and need for investigation of incidental prostatic uptake in men undergoing ^(18)F-labelled fluorodeoxyglucose(^(18)F-FDG) positron emission tomography/computed tomography(PET/CT) for other indications.METHODS Hospital databases were searched over a 5-year period for patients undergoing both PET/CT and prostate magnetic resonance imaging(MRI). For the initial analysis, the prostate was divided into six sectors and suspicious or malignant sectors were identified using MRI and histopathology reports respectively. Maximum and mean ^(18)F-FDG standardised uptake values were measured in each sector by an investigator blinded to the MRI and histopathology findings. Two agematched controls were selected per case. Results were analysed using a paired t-test and one-way ANOVA. For the second analysis, PET/CT reports were searched for prostatic uptake reported incidentally and these patients were followed up. RESULTS Over a 5-year period, 15 patients underwent both PET/CT and MRI and had biopsy-proven prostate cancer.Malignant prostatic sectors had a trend to higher ^(18)F-FDG uptake than benign sectors, however this was neither clinically nor statistically significant(3.13 ±0.58 vs 2.86 ± 0.68, P > 0.05). ^(18)F-FDG uptake showed no correlation with the presence or histopathological grade of tumour. ^(18)F-FDG uptake in cases with prostate cancer was comparable to that from age-matched controls. Forty-six(1.6%) of 2846 PET/CTs over a 5-year period reported incidental prostatic uptake. Of these, 18(0.6%) were investigated by PSA, 9(0.3%)were referred to urology, with 3(0.1%) undergoing MRI and/or biopsy. No cases of prostate cancer were diagnosed in patients with incidental ^(18)F-FDG uptake in our institute over a 5-year period.CONCLUSION ^(18)F-FDG uptake overlaps significantly between malignant and benign prostatic conditions. Subsequent patient management was not affected by the reporting of incidental focal prostatic uptake in this cohort.

Fluorodeoxyglucose positron emission tomography/computed tomography and magnetic resonance imaging of uterine leiomyosarcomas： 2 cases report

Uterine leiomyosarcoma is an uncommon malignant neoplasm of smooth muscle origination and is associated with a poor prognosis. We report two cases of uterine leiomyosarcoma that presented with pulmonary metastases.2-deoxy-2-（18F）fluorodeoxyglucose （FDG） positron emission tomography （PET）/computed tomography （CT） was performed to identify the primary carcinoma and found the focus located in the uterus. The follow-up magnetic resonance imaging （MRI） confirmed the diagnosis was uterine leiomyosarcoma.

Combination of 18F-fluorodeoxyglucose positron emission tomography/computed tomography and magnetic resonance imaging is an optimal way to evaluate rheumatoid arthritis in rats dynamically

Background Rheumatoid arthritis （RA） is a chronic,systemic autoimmune inflammatory disorder.Many methods have been used to observe the progress of RA.The purpose of this study was to observe the progress of RA in rats with 18F-fluorodeoxyglucose （FDG） positron emission tomography/computed tomography （PET/CT）,magnetic resonance （MR） imaging and arthritis score,and analyze the relationships among different methods in evaluation of RA.Methods Sixteen healthy Sprague Dawley （SD） rats about 8-week old were randomly assigned to a RA group and a control group.Bovine type Ⅱ emulsified incomplete Freud＇s adjuvant was used to induce arthritis in the RA group.Arthritis score of the rats in two groups were recorded,and 18F-FDG PET/CT,MR imaging were performed both on the corresponding rats every 3 days.All the rats were sacrificed at week 5,and histopathological examination was performed on rat knees stained with haematoxylin and eosin.Results The arthritis score and the standard uptake value （SUV） of knee joints in RA rats increased with the progression of arthritis gradually.Both peaks of arthritis score and SUV appeared at 21 days after the first immune injection,then the arthritis score and SUV of knee joints decreased slowly.The arthritis scores of knee joints in RA rats were positively correlated with their SUV changes.The MR images were confirmed by the histopathological studies.Conclusion PET/CT can detect the earliest molecular metabolism changes of RA,and MR imaging can follow up the dynamical anatomical changes of RA,all of which indicated that PET/CT and MR imaging may be applied as useful tools to monitor the progress of RA.

Diffusion-weighted magnetic resonance imaging with short T1 inversion recovery-echo planar imaging combined with dual-head coincidence single photon emission computed tomography for diagnosing solitary pulmonary nodule

Positron emission tomography （PET） using 18F-fluorodeoxyglucose （FDG） has not been widely used in China for expensive cost （$1200）. Dual-head coincidence single photon emission computed tomography （DHC-SPECT） can depict many of the lesions depicted with a PET scanner in the lungs, which is used in place of PET-CT for discriminating malignant from benign pulmonary nodules in many studies. However, DHC-SPECT has inevitable false-negative results because the sensitivity for small lesions less than 2.0 cm is limited, and has high false-positive rate for active inflammatory nodules. Furthermore,DHC-SPECT also has a considerably higher cost （$300 in China） than other imaging examination.

Multimodal imaging in the diagnosis of bone giant cell tumors:A retrospective study

BACKGROUND Giant cell tumor of bone is a locally aggressive and rarely metastasizing tumor,and also a potential malignant tumor that may develop into a primary malignant giant cell tumor.AIM To evaluate the role of multimodal imaging in the diagnosis of giant cell tumors of bone.METHODS The data of 32 patients with giant cell tumor of bone confirmed by core-needle biopsy or surgical pathology at our hospital between March 2018 and March 2023 were retrospectively selected.All the patients with giant cell tumors of the bone were examined by X-ray,computed tomography(CT)and magnetic resonance imaging(MRI),and 7 of them were examined by positron emission tomography(PET)-CT.RESULTS X-ray imaging can provide overall information on giant cell tumor lesions.CT and MRI can reveal the characteristics of the internal structure of the tumor as well as the adjacent relationships of the tumor,and these methods have unique advantages for diagnosing tumors and determining the scope of surgery.PET-CT can detect small lesions and is highly valuable for identifying benign and malignant tumors to aid in the early diagnosis of metastasis.CONCLUSION Multimodal imaging plays an important role in the diagnosis of giant cell tumor of bone and can provide a reference for the treatment of giant cell tumors.

Recent Research Advances in Imaging of Prostate Cancer

Imaging study plays a crucial role in the diagnosis of prostate cancer. As early screening and management of prostate cancer has evolved over the past decade, research is now focusing on how to detect clinically significant prostate cancer and avoid overdiagnosis accurately. This article provides an overview of recent advances in imaging in prostate cancer diagnosis, including new ultrasound imaging techniques, positron emission computed tomography, multiparametric magnetic resonance imaging, and emerging areas such as imaging histology, by systematically reviewing and summarizing the existing literature.

局灶性皮层发育不良影像学研究进展

局灶性皮层发育不良(FCD)是药物难治性癫痫的常见病因之一。手术切除致痫灶是目前治疗FCD所致药物难治性癫痫最有效的方式。影像学检查是诊断FCD的常见手段,术前发现病灶并精确定位对手术方案的制定及患者术后的效果至关重要。近年来随着科学技术的发展,影像学检查相关的硬件和软件设施及后处理技术也越来越先进,能更早期、更精确地发现致痫灶,对指导最佳手术方案的制定,追求术后无癫痫发作及更少的神经心理学损伤具有重要意义。因此,本文就近几年提高FCD检出率的相关影像学研究进行综述,以期为临床医生在抉择术前评估方法时提供更详尽的参考。

Current imaging strategies for the evaluation of uterine cervical cancer

Uterine cervical cancer still remains an important socioeconomic issue because it largely affects women of reproductive age.Prognosis is highly depended on extent of the disease at diagnosis and,therefore,accurate staging is crucial for optimal management.Cervical cancer is clinically staged,according to International Federation of Gynecology and Obstetrics guidelines,but,currently,there is increased use of cross sectional imaging modalities [computed tomography(CT),magnetic resonance imaging(MRI),positron emission tomography-CT(PET-CT)] for the study of important prognostic factors like tumor size,parametrial invasion,endocervical extension,pelvic side wall or adjacent/distal organs involvement and lymph node status.Imaging indications also include cervical cancer follow-up,evaluation of tumor response to treatment and selection of suitable candidates for less radical surgeries like radical trachelectomy for fertility preservation.The preferred imaging method for local cervical cancer evaluation is MRI;CT is equally effective for evaluation of extrauterine spread of the disease.PETCT shows high diagnostic performance for the detection of tumor relapse and metastatic lymph nodes.The aim of this review is to familiarize radiologists with the MRI appearance of cervical carcinoma and to discuss the indications of cross sectional imaging during the course of the disease in patients with cervical carcinoma.

Autoimmune pancreatitis in the context of IgG4-related disease:Review of imaging findings

Current understanding of autoimmune pancreatitis (AIP) recognizes a histopathological subtype of the disease to fall within the spectrum of IgG4-related disease. Along with clinical, laboratory, and histopathological data, imaging plays an important role in the diagnosis and management of AIP, and more broadly, within the spectrum of IgG4-related disease. In addition to the defined role of imaging in consensus diagnostic protocols, an array of imaging modalities can provide complementary data to address specific clinical concerns. These include contrast-enhanced computed tomography (CT) and magnetic resonance (MR) imaging for pancreatic parenchymal lesion localization and characterization, endoscopic retrograde and magnetic resonance cholangiopancreatography (ERCP and MRCP) to assess for duct involvement, and more recently, positron emission tomography (PET) imaging to assess for extra-pancreatic sites of involvement. While the imaging appearance of AIP varies widely, certain imaging features are more likely to represent AIP than alternate diagnoses, such as pancreatic cancer. While nonspecific, imaging findings which favor a diagnosis of AIP rather than pancreatic cancer include: delayed enhancement of affected pancreas, mild dilatation of the main pancreatic duct over a long segment, the “capsule” and “penetrating duct” signs, and responsiveness to corticosteroid therapy. Systemic, extra-pancreatic sites of involvement are also often seen in AIP and IgG4-related disease, and typically respond to corticosteroid therapy. Imaging by CT, MR, and PET also play a role in the diagnosis and monitoring after treatment of involved sites.

Feasibility of prostatectomy without prostate biopsy in the era of new imaging technology and minimally invasive techniques

BACKGROUND Routinely, after receiving prostate specific antigen (PSA) testing and digital rectum examination, patients with suspected prostate cancer are required to undergo prostate biopsy. However, the ability of ultrasound-guided prostate biopsy to detect prostate cancer is limited. Nowadays, a variety of diagnostic methods and more sensitive diagnostic methods, such as multi-parameter prostate magnetic resonance imaging (mpMRI) and prostate-specific membrane antigen positron emission tomography/computed tomography (PSMA PET/CT) can be applied clinically. Furthermore, laparoscopic/robot-assisted prostatectomy is also a safe and effective procedure for the treatment of benign prostatic hyperplasia. So maybe it is time to reconsider the necessary to perform prostate biopsy before radical prostatectomy. AIM To explore the feasibility of radical prostatectomy without prostate biopsy in the era of new imaging technology and minimally invasive techniques. METHODS From June 2014 to November 2018, 11 cases of laparoscopic radical prostatectomy without prostate biopsy were performed at the three tertiary medical centers involved in this study. All patients received prostate magnetic resonance imaging and prostate cancer was suspected, including six patients with positive 68Ga- PSMA PET/CT results. Laparoscopic radical prostatectomy and pelvic lymph node dissection were performed for all patients. RESULTS All surgeries were accomplished successfully. The mean age was 69 ± 7.7 year, the mean body mass index was 24.7 ± 1.6 kg/m2, the range of serum PSA was 4.3 to >1000 ng/mL, and the mean prostate volume was 40.9 ± 18.3 mL. The mean operative time was 96 ± 23.3 min, the mean estimated blood loss was 90 ± 90.9 mL, and the median duration of catheter placement was 14 d. The final pathology confirmed that all specimens were prostate cancer except one case of benign prostatic hyperplasia. No major complications occurred in 90 d postoperatively. CONCLUSION The current practice of mandating a prostatic biopsy before prostatectomy should be reconsidered in the era of new imaging technology and minimally invasive techniques. Radical prostatectomy could be carried out without the evidence of malignancy. Large-sample randomized controlled trials are definitely required to confirm the feasibility of this new concept.

Imaging biomarkers for the treatment of esophageal cancer

Esophageal cancer is known as one of the malignant cancers with poor prognosis.To improve the outcome,combined multimodality treatment is attempted.On the other hand,advances in genomics and other“omic”technologies are paving way to the patient-oriented treatment called“personalized”or“precision”medicine.Recent advancements of imaging techniques such as functional imaging make it possible to use imaging features as biomarker for diagnosis,treatment response,and prognosis in cancer treatment.In this review,we will discuss how we can use imaging derived tumor features as biomarker for the treatment of esophageal cancer.

Imaging of pancreatic ductal adenocarcinoma: State of the art

Significant advances in imaging technology have changed the management of pancreatic cancer. In computed tomography (CT), this has included development of multidetector row, rapid, thin-section imaging that has also facilitated the advent of advanced reconstructions, which in turn has offered new perspectives from which to evaluate this disease. In magnetic resonance imaging, advances including higher field strengths, thin-section volumetric acquisitions, diffusion weighted imaging, and liver specific contrast agents have also resulted in new tools for diagnosis and staging. Endoscopic ultrasound has resulted in the ability to provide high-resolution imaging rivaling intraoperative ultrasound, along with the ability to biopsy via real time imaging suspected pancreatic lesions. Positron emission tomography with CT, while still evolving in its role, provides whole body staging as well as the unique imaging characteristic of metabolic activity to aid disease management. This article will review these modalities in the diagnosis and staging of pancreatic cancer.

Different imaging techniques in the head and neck:Assets and drawbacks

In this review,the gold standard imaging techniques for the head and neck and the latest upcoming techniques are presented,by comparing computed tomography(CT),magnetic resonance imaging and positron emission tomography-CT,as well as ultrasound,depending on the examined area.The advantages and disadvantages of each examination protocol are presented.This article illustrates the connection between the imaging technique and the examined area.Therefore,the head and neck area is divided into different sections such as bony structures,nervous system,mucous membranes and squamous epithelium,glandular tissue,and lymphatic tissue and vessels.Finally,the latest techniques in the field of head and neck imaging such as multidetector CT,dual-energy CT,flash CT,magnetic resonance angiography,spectroscopy,and diffusion tensor tractography using 3 tesla magnetic resonance are discussed.