Utility of Preoperative Positron Emission Tomography (PET) in Localizing Perforator Vessels of Anterolateral Thigh Free Flap

Objectives: The anterolateral thigh (ALT) flap is often considered the workhorse in soft tissue reconstruction of head and neck defects secondary to trauma, infection, or tumor resection. Despite its many advantages, ALT flaps have been criticized due to variability in vasculature, which may result in inadequate or non-existent perforators. This retrospective study aims to investigate the utility and validity of positron emission tomography (PET) scan to identify the location and characteristics of perforators to the ALT flap. Methods: We performed a 10-year retrospective review of ALT flaps at our institution to identify patients with preoperative PET scans available for analysis. Three reviewers (attending physician, fellow, and resident) were asked to identify the number, location, and characteristics (myocutaneous versus septocutaneous) of ALT perforators on imaging, and reviewer agreement was assessed. Results were then compared to available operative data. Results: One hundred twenty-one patients were identified who underwent ALT free flap surgery. Thirty-eight preoperative PET scans were identified for review. At least one perforator was identified in 92.1% of scans. Agreement percentages regarding the number of perforators ranged from 53% - 61% whereas agreement regarding the location of a single perforator ranged from 79% - 90%. However, reviewers did not agree regarding the type of perforator, with agreement ranging from 34% - 53%. Poor agreement was observed when compared to intraoperative data, with the number of perforators ranging from 26% - 34% and the type of perforator 11% - 24%. These findings are likely due to insufficient data available in operative reports. Conclusion: Although initial studies suggest that PET scan shows promising evidence to support the capacity to preoperatively identify ALT perforators, future prospective studies are warranted to fully validate these findings.

Recent progress in the applications of presynaptic dopaminergic positron emission tomography imaging in parkinsonism

Nowadays,presynaptic dopaminergic positron emission tomography,which assesses deficiencies in dopamine synthesis,storage,and transport,is widely utilized for early diagnosis and differential diagnosis of parkinsonism.This review provides a comprehensive summary of the latest developments in the application of presynaptic dopaminergic positron emission tomography imaging in disorders that manifest parkinsonism.We conducted a thorough literature search using reputable databases such as PubMed and Web of Science.Selection criteria involved identifying peer-reviewed articles published within the last 5 years,with emphasis on their relevance to clinical applications.The findings from these studies highlight that presynaptic dopaminergic positron emission tomography has demonstrated potential not only in diagnosing and differentiating various Parkinsonian conditions but also in assessing disease severity and predicting prognosis.Moreover,when employed in conjunction with other imaging modalities and advanced analytical methods,presynaptic dopaminergic positron emission tomography has been validated as a reliable in vivo biomarker.This validation extends to screening and exploring potential neuropathological mechanisms associated with dopaminergic depletion.In summary,the insights gained from interpreting these studies are crucial for enhancing the effectiveness of preclinical investigations and clinical trials,ultimately advancing toward the goals of neuroregeneration in parkinsonian disorders.

Guiding function of positron emission tomographycomputed tomography examination in the diagnosis and treatment of ocular adnexal mucosa associated lymphoid tissue lymphoma

AIM:To explore the role of positron emission tomographycomputed tomography(PET-CT)examination in the diagnosis and treatment of ocular adnexal mucosa associated lymphoid tissue lymphoma(OAML).METHODS:The general clinical data,postoperative PET-CT results,treatment regimens,and the prognosis of 21 histopathologically confirmed OAML patients between October 2017 and September 2021 were collected.Among the 21 patients,five patients underwent surgical treatment alone,13 patients underwent surgical treatment combined with radiotherapy,and three patients underwent surgical treatment combined with chemotherapy.RESULTS:The follow-up period ranged from 8 to 79mo,with four cases of recurrence and no deaths.Through PETCT examination,two patients exhibited both local ocular metabolic elevation and systemic metastasis,and one of these patients had cervical lymph node metastasis,while the other had submandibular and parotid gland metastasis.Nine patients showed only local ocular metabolic elevation,while 10 patients had no abnormal metabolic activity locally.CONCLUSION:PET-CT examination plays a crucial role in detecting residual lesions and recurrence following tumor resection,aiding in precise disease staging,and facilitating the development of personalized treatment plans,ultimately improving patient prognosis.

Rim^(18)F-fluorodeoxyglucose uptake of hepatic cavernous hemangioma on positron emission tomography/computed tomography:A case report

BACKGROUND Peripheral FDG accumulation in a hepatic hemangioma presenting in a patient with prolonged fever is rare.Therefore,clinicians should pay close attention to patients with hepatic mass.CASE SUMMARY A 54-year-old woman with a 4-wk history of daily fevers was admitted to our hospital.A whole body^(18)-Fluordesoxyglucose(PET-FDG)positron emission tomography/computed tomography(PET/CT)was performed to elucidate the source of the fever.However,whole body^(18)-FDG PET/CT raised the suspicion of a malignant lesion because of peripheral FDG accumulation(SUVmax 3.5 g/mL)higher than that of the normal liver parenchyma(SUVmax 1.6 g/mL)surrounding a hypoactive area,and no other abnormalities were showed.Subsequently,the patient underwent liver mass resection.Histopathology showed a hepatic cavernous hemangioma with fatty infiltration around the lesion.The fever disappeared four days after surgery and the patient did not present any complications during follow-up.CONCLUSION Fatty infiltration in the peripheral parts of hepatic cavernous hemangioma may lead to subacute inflammation which further activate the Kupffer cells.This may cause prolonged fever and peripheral rim FDG accumulation on PET/CT.

Application of ^(18)F-fluorodeoxyglucose positron emission tomography/computed tomography imaging in recurrent anastomotic tumors after surgery in digestive tract tumors

BACKGROUND This study was to investigate the application value of whole-body dynamic ^(18)F-fluorodeoxyglucose(FDG)positron emission tomography/computed tomogra-phy(PET/CT)imaging in recurrent anastomotic tumors of digestive tract after gastric and esophageal cancer surgery.Postoperative patients with gastric and esophageal cancer have a high risk of tumor recurrence,and traditional imaging methods have certain limitations in early detection of recurrent tumors.Whole-body dynamic ^(18)F-FDG PET/CT imaging,due to its high sensitivity and specifi-city,can provide comprehensive information on tumor metabolic activity,which is expected to improve the early diagnosis rate of postoperative recurrent tumors,and provide an important reference for clinical treatment decision-making.METHODS A retrospective analysis was performed on 53 patients with upper digestive tract tumors after operation and systemic dynamic ^(18)F-FDG PET/CT imaging indi-cating abnormal FDG uptake by anastomosis,including 29 cases of gastric cancer and 24 cases of esophageal cancer.According to the follow-up results of gas-troscopy and other imaging examinations before and after PET/CT examination,the patients were divided into an anastomotic recurrence group and anastomotic inflammation group.Patlak multi-parameter analysis software was used to obtain the metabolic rate(MRFDG),volume of distribution maximum(DVmax)of anastomotic lesions,and MRmean and DVmean of normal liver tissue.The lesion/background ratio(LBR)was calculated by dividing the MRFDG and DVmax of the anastomotic lesion by the MRmean and DVmean of the normal liver tissue,respectively,to obtain LBR-MRFDG and LBR-DVmax.An independent sample t test was used for statistical analysis,and a receiver operating characteristic curve was used to analyze the differential diagnostic efficacy of each parameter for anastomotic recurrence and inflammation.RESULTS The dynamic ^(18)F-FDG PET/CT imaging parameters MRFDG,DVmax,LBR-MRFDG,and LBR-DVmax of postoperative anastomotic lesions in gastric cancer and esophageal cancer showed statistically significant differences between the recurrence group and the inflammatory group(P<0.05).The parameter LBR-MRFDG showed good diagnostic efficacy in differentiating anastomotic inflammation from recurrent lesions.In the gastric cancer group,the area under the curve(AUC)value was 0.935(0.778,0.993)when the threshold was 1.83,and in the esophageal cancer group,the AUC value was 1.When 86 is the threshold,the AUC value is 0.927(0.743,0.993).CONCLUSION Whole-body dynamic ^(18)F-FDG PET/CT imaging can accurately differentiate the diagnosis of postoperative anastomotic recurrence and inflammation of gastric cancer and esophageal cancer and has the potential to be an effective monitoring method for patients with upper digestive tract tumors after surgical treatment.

Impact of random and scattered coincidences from outside of field of view on positron emission tomography/computed tomography imaging with different reconstruction protocols

Image quality in positron emission tomography(PET)is affected by random and scattered coincidences and reconstruction protocols.In this study,we investigated the effects of scattered and random coincidences from outside the field of view(FOV)on PET image quality for different reconstruction protocols.Imaging was performed on the Discovery 690 PET/CT scanner,using experimental configurations including the NEMA phantom(a body phantom,with six spheres of different sizes)with a signal background ratio of 4:1.The NEMA phantom(phantom I)was scanned separately in a one-bed position.To simulate the effect of random and scatter coincidences from outside the FOV,six cylindrical phantoms with various diameters were added to the NEMA phantom(phantom II).The 18 emission datasets with mean intervals of 15 min were acquired(3 min/scan).The emission data were reconstructed using different techniques.The image quality parameters were evaluated by both phantoms.Variations in the signal-to-noise ratio(SNR)in a 28-mm(10-mm)sphere of phantom II were 37.9%(86.5%)for ordered-subset expectation maximization(OSEM-only),36.8%(81.5%)for point spread function(PSF),32.7%(80.7%)for time of flight(TOF),and 31.5%(77.8%)for OSEM+PSF+TOF,respectively,indicating that OSEM+PSF+TOF reconstruction had the lowest noise levels and lowest coefficient of variation(COV)values.Random and scatter coincidences from outside the FOV induced lower SNR,lower contrast,and higher COV values,indicating image deterioration and significantly impacting smaller sphere sizes.Amongst reconstruction protocols,OSEM+PSF+TOF and OSEM+PSF showed higher contrast values for sphere sizes of 22,28,and 37 mm and higher contrast recovery coefficient values for smaller sphere sizes of 10 and 13 mm.

Polyarteritis nodosa presenting as leg pain with resolution of positron emission tomography-images:A case report

BACKGROUND Although fluorodeoxyglucose-positron emission tomography/computed tomography(FDG-PET/CT)is widely used for diagnosis and follow-up of large sized vessel vasculitis,it is still not widely used for small to medium sized vessel vasculitis.CASE SUMMARY This is the case of a 68-year-old male who presented at the emergency department complaining of fever,myalgia,and bilateral leg pain of over two weeks duration,with elevated levels of C-reactive protein.He was subsequently admitted and despite the absence of clinically significant findings,the patient continued to exhibit recurrent fever.A fever of unknown origin workup,which included imaging studies using FDG-PET/CT,revealed vasculitis involving small to medium-sized vessels of both lower extremities,demonstrated by linear hypermetabolism throughout the leg muscles.The patient was treated with methylprednisolone and methotrexate after diagnosis leading to the gradual resolution of the patient’s symptoms.Three weeks later,a follow-up FDGPET/CT was performed.Previously hypermetabolic vessels were markedly improved.CONCLUSION Our case report demonstrated that FDG-PET/CT has tremendous potential to detect medium-sized vessel inflammation;it can also play a crucial role in prognosticating outcomes and monitoring therapeutic efficacy.

Evaluation of response to gemcitabine plus cisplatin-based chemotherapy using positron emission computed tomography for metastatic bladder cancer

BACKGROUND The purpose of the present study was to examine retrospectively the contribution of 18Fluorodeoxyglucose positron emission tomography computed tomography(18FDG-PET/CT)to the evaluation of response to first-line gemcitabine plus cispla-tin-based chemotherapy in patients with metastatic bladder cancer.AIM To evaluate the response to Gemcitabine plus Cisplatin-based chemotherapy using 18FDG-PET/CT imaging in patients with metastatic bladder cancer.METHODS Between July 2007 and April 2019,79 patients underwent 18FDG-PET/CT imaging with the diagnosis of Metastatic Bladder Carcinoma(M-BCa).A total of 42 pa-tients(38 male,4 female)were included in the study,and all had been admi-nistered Gemcitabine plus Cisplatin-based chemotherapy.After completion of the therapy,the patients underwent a repeat 18FDG-PET/CT scan and the results were compared with the PET/CT findings before chemotherapy according to European Organisation for the Research and treatment of cancer criteria.Mean age was 66.1 years and standard deviation was 10.7 years(range:41–84 years).RESULTS Of the patients,seven(16.6%)were in complete remission,17(40.5%)were in partial remission,six(14.3%)had a stable disease,and 12(28.6%)had a pro-gressive disease.The overall response rate was 57.1 percent.CONCLUSION 18FDG-PET/CT can be considered as a successful imaging tool in evaluating response to first-line chemotherapy for metastatic bladder cancer.Anatomical and functional data obtained from PET/CT scans may be useful in the planning of secondline and thirdline chemotherapy.

Appearance of aseptic vascular grafts after endovascular aortic repair on[(18)F]fluorodeoxyglucose positron emission tomography/computed tomography

BACKGROUND Diagnosis of prosthetic vascular graft infection with[(18)F]fluorodeoxyglucose positron emission tomography/computed tomography(18F-FDG PET/CT)allows for early detection of functional changes associated with infection,based on increased glucose utilization by activated macrophages and granulocytes.Aseptic vascular grafts,like all foreign bodies,can stimulate an inflammatory response,which can present as increased activity on 18F-FDG PET/CT.Consequently,distinguishing aseptic inflammation from graft infection,though important,can be difficult.In the case of endovascular aneurysm repair(EVAR),a minimally invasive procedure involving the transfemoral insertion of an endoprosthetic stent graft,the normal postoperative appearance of these grafts on 18F-FDG PET/CT can vary over time,potentially confounding study interpretation.AIM To investigate the visual,semiquantitative,and temporal characteristics of aseptic vascular grafts in patients status post EVAR.METHODS In this observational retrospective cohort study,patients with history of EVAR who underwent 18F-FDG PET/CT for indications other than infection were identified retrospectively.All patients were asymptomatic for graft infection-no abdominal pain,fever of unknown origin,sepsis,or leukocytosis-at the time of imaging and for≥2 mo after each PET/CT.Imaging studies such as CT for each patient were also reviewed,and any patients with suspected or confirmed vascular graft infection were excluded.One hundred two scans performed on 43 patients(34 males;9 females;age=77±8 years at the time of the final PET/CT)were retrospectively reviewed.All 43 patients had an abdominal aortic(AA)vascular graft,40 patients had a right iliac(RI)limb graft,and 41 patients had a left iliac(LI)limb graft.Twentytwo patients had 1 PET/CT and 21 patients had from 2 to 9 PET/CTs.Grafts were imaged between 2 mo to 168 mo(about 14 years)post placement.Eight grafts were imaged within 6 mo of placement,including three that were imaged within three months of placement.The mean interval between graft placement and PET/CT for all 102 scans was 51±39 mo.PET/CT data was reconstructed with region-of-interest analysis of proximal,mid and distal portions of the grafts and background ascending aorta.Maximum standardized uptake value(SUVmax)was recorded for each region.SUVmax-to-background uptake ratios(URs)were calculated.Visual assessment was performed using a 2-pattern grading scale:Diffuse(homogeneous uptake less than liver uptake)and focal(one or more areas of focal uptake in any part of the graft).Statistical analysis was performed.RESULTS In total,there were 306 AA grafts,285 LI grafts,282 RI grafts,and 306 ascending aorta background SUVmax measurements.For all 102 scans,mean SUVmax values for AA grafts were 2.8-3.0 along proximal,mid,and distal segments.Mean SUVmax values for LI grafts and RI grafts were 2.7-2.8.Mean SUVmax values for background were 2.5±0.5.Mean URs were 1.1-1.2.Visual analysis of the scans reflected results of quantitative analysis.On visual inspection,98%revealed diffuse,homogeneous 18F-FDG uptake less than liver.Graft URs and visual pattern categories were significantly associated for AA graft URs(F-ratio=21.5,P<0.001),LI graft URs(F-ratio=20.4,P<0.001),and RI graft URs(F-ratio=30.4,P<0.001).Thus,visual patterns of 18F-FDG uptake corresponded statistically significantly to semiquantitative URs.The age of grafts showing focal patterns was greater than grafts showing diffuse patterns,87±89 vs 50±37 mo,respectively(P=0.02).URs were significantly associated with graft age for AA grafts(r=0.19,P=0.001).URs were also significantly associated with graft age for LI grafts(r=0.25,P<0.0001),and RI grafts(r=0.31,P<0.001).Quartiles of similar numbers of graft(n=25-27)grouped by graft age indicated that URs were significantly higher for 4th quartile vs 2nd quartile URs(F-ratio=19.5,P<0.001).When evaluating URs,graft SUVmax values within 10%-20%of the ascending aorta SUVmax is evident in aseptic grafts,except for grafts in the oldest quartiles.In this study,grafts in the oldest quartiles(>7 years post EVAR)showed SUVmax up to 30%higher than the ascending aorta SUVmax.CONCLUSION Characteristics of an aseptic vascular stent graft in the aorta and iliac vessels on 18F-FDG PET/CT include graft SUVmax values within 10%-20%of the ascending aorta background SUVmax.The SUVmax of older aseptic grafts can be as much as 30%above background.The visual uptake pattern of diffuse,homogeneous uptake less than liver was seen in 98%of aseptic vascular grafts,making this pattern particularly reassuring for clinicians.

Whole Body Positron Emission Tomography/Computed Tomography （PET/CT） in the Evaluation of Ophthalmic Tumors

The clinical value of whole body positron emission tomography/computed tomography （PET/CT） as an imaging tool in diagnosis of ophthalmic tumors was investigated. The retrospective observational case series were performed on the patients with suspected ophthalmic tumors who underwent whole body PET/CT. The golden standard of diagnosis was the final pathological diagnosis or the results of long-term follow-up for patients without surgery/ biopsy. PET/CT findings were compared with the golden standard. The sensitivity, specificity, accuracy an^t positive likelihood ratio of PET/CT in the detection of ophthalmic tumors were calculated. The clinical application of PET/CT in different types of ophthalmic tumors was evaluated. The results showed that 30 patients （18 males and 12 females） with a mean age of 43.0 years （range 4-63 years） were collected. The mean sizes of orbital tumors and intraocular tumors were 26.8 mmxl7.8 mm and 11.2 minx6.1 mm, respectively. The overall sensitivity, specificity, accuracy and positive likelihood ratio of whole body PET/CT in ophthalmic tumors were 76.5%, 71.4%, 75.0% and 2.67, and were 62.5%, 100% and 70.0% in intraocular tumors, and those were 100%, 60.0% and 84.6% in orbital tumors, respectively. PET/CT findings were applied to help make appropriate treatment options in 27 out of 30 patients （90.0%）, and 12 （40.0%） patients changed the treatment strategy. False negative results in 4 cases and false positive results in 2 cases were observed in this series. It was suggested that PET/CT was an effective imaging modality in detecting, diagnosing and developing therapeutic schedule for patients with ophthalmic tumors. It was more sensitive and accurate for detecting orbital tumors than for detecting intraocular tumors.

Positron Emission Tomography-Computed Tomography (PET-CT) in Head and Neck Pathology

Cancer of the head and neck is often devastating and the morbidity associated with its treatment is substantial. Positron Emission Tomography-Computed Tomography (PET-CT) combines the power of biological / molecular imaging with the anatomic detail of CT in order to provide a very sensitive and specific imaging tool for the evaluation of head and neck pathology. PET can aid the clinician in establishing diagnosis, staging, (It has been shown to be more accurate than CT), assessing, prognosis and determining response to therapy. Lymphoma, melanoma, multiple myeloma, leukemia, salivary gland tumors, odontogenic carcinomas, soft tissue sarcomas, thyroid, parathyroid, lacrimal gland and bone / cartilage tumors are some of the entities where PET-CT may be useful. (Tumors of salivary glands and of odontogenic tissue are particularly difficult to diagnose due to the relative infrequency when compared with other tumors and the extremely vast histologic variation).It is important to note that carcinoma metastasis, is the most common malignancy found within the mandibular bone. PET-CT and skeletal scintigraphy are both very sensitive and specific in these types of patients.

Role of PET-CT (Positron Emission Tomography-Computed Tomography) in Cancer Evaluation and Treatment

Context: Positron emission tomography is a nuclear medicine imaging that deals with physiological function using radioisotopes. With the most PET (Positron Emission Tomography) scanners in integration with the CT scanners of late, this technology has registered phenomenal growth. The small amount of radioactive material is called Radiotracers. Objective: Like 18F- Fluro-deoxy-2-glucose has widely used. In this article, the author introduced clinical applications of PET out of 25 patients who studied hypermetabolic lesions in lymph nodes. Methods: PET imaging is coincidence imaging which is different from the other imaging technique PET image formed from multiple rings of detector crystals. Each decay positron travel in tissue annihilation reaction is going on. FDG is the most commonly used radiotracer to detect and stage various types of malignancies. Result: The field of PET/CT imaging cares for many oncology patients. PET improved localization of malignant lesions. It improved staging biopsy and therapy. Conclusion: Finally, studies to data showed 4% to 10% improvement in the overall accuracy of staging/restaging in lesions. If we use Monte Carlo simulation, OLINDA/EXM software may improve further with widely used.

^(18)F-FDG PET/CT征象及Ki-67表达与肺腺癌EGFR突变相关性研究

目的探讨^(18)F-FDG PET/CT征象及Ki-67表达与肺腺癌表皮生长因子受体(epidermal growth factor receptor,EGFR)突变的相关性。方法回顾分析95例经病理证实肺腺癌患者的^(18)F-FDG PET/CT征象、EGFR突变检测结果、Ki-67表达及一般临床资料。分析PET/CT征象(包括毛刺征、分叶征、胸膜牵拉征、血管集束征、空泡征、支气管截断征、SUVmax)、Ki-67表达、性别、年龄、吸烟史与EGFR突变状态的相关性。采用受试者工作特征(receiver operating characteristic,ROC)曲线计算最大标准摄取值(SUVmax)的截断值,Logistic回归分析影响EGFR突变的预测因素。结果EGFR突变患者的SUVmax值明显低于野生型患者(t=2.813,P=0.006),21号外显子突变患者的SUVmax低于野生型患者(t=3.274,P=0.002),野生型患者与19号外显子突变患者的SUV m a x差异无统计学意义(t=1.323,P=0.193),两种不同类型突变型SUVmax差异无统计学意义(t=-1.579,P=0.124)。ROC曲线分析显示,SUVmax预测EGFR突变的截断值为6.36。EGFR突变患者的Ki-67与野生型相比更易发生低表达(χ^(2)=4.867,P=0.027),21号外显子突变型患者Ki-67表达与野生型差异有统计学意义(χ^(2)=5.576,P=0.018),19号外显子突变型与野生型Ki-67表达差异无统计学意义(χ^(2)=0.328,P=0.567),两种不同类型突变型Ki-67表达差异无统计学意义(χ^(2)=1.791,P=0.181)。单因素分析结果显示,性别、吸烟、分叶征、血管集束征及SUVmax与EGFR突变有关(P<0.05),而年龄、毛刺征、胸膜牵拉征、空泡及支气管截断征与EGFR突变无关(P>0.05)。根据Logistic多因素分析的结果,性别、血管集束征和SUVmax是预测EGFR突变的独立因素(P<0.05)。结论SUVmax是预测肺腺癌EGFR突变的独立因素,在预测EGFR突变中具有一定的参考价值。

脊椎侵袭性血管瘤^(18)F-FDG PET/CT表现

目的观察脊椎侵袭性血管瘤^(18)F-FDG PET/CT表现。方法回顾性收集24例脊椎侵袭性血管瘤患者,病变位于颈椎6例、胸椎14例、腰椎4例;观察其^(18)F-FDG PET/CT特点,比较具有不同CT表现病灶的最大标准摄取值(SUV_(max))。结果24例中,5例(5/24,20.83%)病变局限于椎体、19例(19/24,79.17%)病变累及椎体及附件;其中10例(10/24,41.67%)病变椎体见溶骨性破坏及内部残留骨质,6例(6/24,25.00%)伴单纯溶骨性破坏,4例(4/24,16.67%)伴骨小梁增粗、稀疏,4例(4/24,16.67%)骨质未见明显异常。相比邻近非病变椎体,12例(12/24,50.00%)病灶放射性摄取增高、9例(9/24,37.50%)接近、3例(3/24,12.50%)减低;14例(14/24,58.33%)放射性分布均匀、10例(10/24,41.67%)不均匀。24例血管瘤的SUV_(max)[2.50(1.53,4.13)]与肝脏SUV_(max)(2.79±0.53)差异无统计学意义(Z=0.261,P=0.794);其中,伴骨皮质破坏病灶的SUV_(max)高于无破坏病灶(P<0.05),伴骨折病灶的SUV_(max)高于无骨折病灶(P<0.05)。结论脊椎侵袭性血管瘤CT表现多样,其^(18)F-FDG代谢接近肝脏,合并骨皮质破坏及骨折病灶的代谢较高。

^(18)F-FDG PET/CT诊断肾细胞癌伴下腔静脉癌栓侵犯下腔静脉壁

目的 观察^(18)F-FDG PET/CT诊断肾细胞癌(RCC)伴下腔静脉(IVC)癌栓侵犯IVC壁的价值。方法 回顾性分析71例接受手术治疗的RCC伴IVC癌栓患者,根据癌栓是否侵犯IVC壁分为侵犯组(n=40)及无侵犯组(n=31);比较组间一般资料和PET/CT特征,分析各指标诊断癌栓侵犯IVC壁的效能。结果 组间原发灶最大标准摄取值(SUV_(max))、癌栓比、癌栓最大横径、长径,以及病理类型差异均有统计学意义(P均<0.05)。癌栓比和癌栓最大横径为RCC伴IVC癌栓侵犯IVC壁的影响因素(P均<0.05)。以1.33为最佳截断值,根据癌栓比诊断RCC伴IVC癌栓侵犯IVC壁的敏感度为47.50%,特异度为87.10%,AUC为0.70;以3.45 cm为最佳截断值,根据癌栓最大横径诊断的敏感度为65.00%,特异度为87.10%,AUC为0.81;二者联合诊断敏感度为90.00%,特异度为77.40%,AUC为0.86。结论 以^(18)F-FDG PET/CT所获癌栓比及癌栓最大横径可用于术前诊断RCC伴IVC癌栓侵犯IVC壁。

1例初始表现为急性弥散性血管内凝血的胃低分化腺癌伴多发转移:^(18)F-FDG PET/CT显像所见

患者女,20岁,无明显诱因阵发性下腹部疼痛伴牙龈出血、皮肤散在瘀斑及肛门坠胀感9天;既往体健。查体:贫血貌,全身皮肤散在片状瘀斑,四肢皮肤干燥;腹部柔软,无压痛及反跳痛。实验室检查:红细胞2.49×10^(12)/L,血小板36×10^(9)/L,血红蛋白70 g/L,血浆鱼精蛋白副凝固实验(+),D-二聚体>20 mg/L,纤维蛋白原降解产物>150.00 mg/L,糖类抗原12573.40 U/ml。

自身免疫性脑炎^(18)F-FDG PET/MR表现的初步研究

目的 探索自身免疫性脑炎(autoimmune encephalitis, AE)患者^(18)F-氟代脱氧葡萄糖(fludeoxyglucose, FDG)正电子发射/磁共振计算机断层显像(positron emission tomography/magnetic resonance, PET/MR)表现,寻找提高疾病诊断效能的影像学标记物。材料与方法 回顾性分析25例AE患者(AE组)和11例健康对照(healthy controls, HC)(HC组)的资料。所有研究对象均采集头颅^(18)F-FDG PET/MR影像。首先,使用统计参数图12(statistical parametric mapping 12, SPM12)处理包得出AE组FDG摄取异常脑区。然后,使用后处理工作站多模态脑分析软件提取脑区体积/全脑体积(volume/total intracranial volume,volume/TIV)和平均标准化摄取率(standardized uptake value ratio, SUVr)参数,比较AE组与HC组各个脑区volume/TIV和SUVr的组间差异,并分别选取volume/TIV和SUVr有显著差异的脑区绘制受试者工作特征(receiver operating characteristic,ROC)曲线,计算单一定量参数及定量参数两两联合的诊断效能。最后,进行DeLong检验选择最佳模型,绘制联合诊断校准曲线和决策曲线评估预测模型的准确性,置换检验用于评估统计量的显著性。结果 SPM12的分析显示,AE组脑干和小脑FDG摄取增高(P<0.001),而双侧额叶、顶叶、右侧枕叶FDG摄取减低(P<0.001)。脑结构分析结果显示岛叶、扣带回、距状回volume/TIV减低(P<0.05),中扣带回、顶叶、楔叶、枕外侧回SUVr减低(P<0.05)。ROC曲线分析发现左侧距状回的volume/TIV和左侧中扣带回的SUVr联合诊断效能(曲线下面积=0.964)最高。DeLong检验显示定量参数两两联合诊断效能与单一参数诊断效能差异具有统计学意义(P<0.05)。校准曲线显示诊断模型的校准度一般,但决策曲线显示在一定风险阈值范围内患者可获得比较高的净收益。置换检验显示AE组及HC组的左侧距状回的volume/TIV和左侧中扣带回的SUVr之间差异具有统计学意义。结论 AE患者^(18)F-FDG PET/MR存在某些特定脑区FDG代谢异常和脑体积改变,左侧距状回的volume/TIV和左侧中扣带回SUVr两个参数联合是潜在诊断AE的生物学标记物。

不同重建方法对颞叶癫痫患者FDG PET图像质量及诊断效能的影响

目的评估飞行时间(TOF)联合点扩散函数(PSF)重建对于颞叶癫痫(TLE)患者脑PET图像及病灶定位诊断的价值。方法回顾性收集2017年至2019年间首都医科大学宣武医院52例住院TLE患者[男30例、女22例,年龄(26.7±7.1)岁]和26名健康志愿者[男14名、女12名,年龄(31.7±6.8)岁]的脑18F-FDG PET显像数据,图像采用4种方式重建:有序子集最大期望值迭代法(OSEM)、OSEM+TOF、OSEM+PSF、OSEM+TOF+PSF。采用4分制法视觉评估所有被试的图像质量、清晰度、噪声以及患者病灶显示的清晰度,计算所有被试图像的信噪比(SNR)、对比度以及患者病灶的不对称指数(AI)。采用单因素方差分析对4种重建方式之间上述参数的差异进行比较。对PET图像定位致痫灶的效能进行ROC曲线分析。结果健康志愿者PET图像的视觉评分以OSEM+TOF+PSF组最高[(4.0±0.0)分],与OSEM组相比,OSEM+TOF+PSF组图像SNR降低46.6%(SNR数据越小,图像质量越好),图像对比度提升29.8%。TLE PET图像视觉评估显示,OSEM+TOF+PSF组、OSEM+PSF组、OSEM+TOF组和OSEM组的评分依次减低,分别为(4.0±0.0)、(3.4±0.5)、(2.3±0.4)和(1.0±0.0)分(F=884.0,P<0.001)。定量分析显示上述4组图像的SNR依次增高:(5.2±2.4)%、(6.2±2.4)%、(7.9±2.6)%、(8.9±3.5)%(F=18.82,P<0.001);图像对比度及病灶AI的4组排序则为OSEM+TOF+PSF组(对比度:0.81±0.03;AI:0.28±0.05)>OSEM+TOF组(0.74±0.05;0.23±0.06)>OSEM+PSF组(0.72±0.06;0.22±0.07)>OSEM组(0.64±0.05;0.19±0.06)(F值:107.10、19.94,均P<0.001)。52例TLE患者中32例MRI检出单侧海马硬化,20例为MRI阴性患者。ROC曲线分析示,发作间期OSEM+TOF+PSF PET图像目视法及病灶/对侧SUV比值(SUVR)对单侧海马硬化组定位致痫灶的AUC为0.874,对MRI阴性组定位致痫灶的AUC为0.932。结论TOF和PSF技术能够提高PET图像质量,二者联合应用后效果最佳并有助于定位TLE患者的致痫灶。

骨髓坏死^(18)F-FDG PET/CT与MRI对照分析

目的探索骨髓坏死氟-18-脱氧葡萄糖(^(18)F-fluorodeoxyglucose,^(18)F-FDG)正电子发射断层显像/计算机断层显像(positron emission tomography/computed tomography,PET/CT)表现,提高对该病的认识。方法回顾性分析9例磁共振成像(magnetic resonance imaging,MRI)诊断为骨髓坏死患者的PET/CT及临床资料,对照MRI影像,总结病变分布,选择最大病变,分析^(18)F-FDG代谢特点及CT征象。结果患者男6例,女3例,中位年龄28.0岁,均患淋巴瘤。MRI检查髋部6例、胸腰椎2例、膝部1例。6例髂骨病变,内部均为T1加权像(T1-weighted image,T1WI)高信号,T2脂肪抑制像(T2-fat suppressed image,T2FSI)低信号,伴T1WI边缘环状低信号,其中5例内部代谢减低,边缘代谢增高伴骨质硬化;1例密度及代谢未见异常,MRI显示病变狭长。2例脊柱病变T1WI呈等、低信号,T2FSI高信号,其中1例为等代谢,密度稍高;1例代谢减低,密度未见异常。1例股骨病变T1WI高信号,T2FSI低信号,代谢及密度增高。8例PET/CT发现MRI检查范围之外更多病变。8例更早期的PET/CT发现部分病变呈低代谢、等密度。结论^(18)F-FDG代谢减低,后期可伴有边缘线状代谢及密度增高,是骨髓坏死的常见PET/CT影像特点。PET/CT有助于检出骨髓坏死,发现多骨病变。

^(18)F-FDG PET/CT在硬脊膜内转移诊断中的应用

目的评价^(18)F-FDG PET/CT在硬脊膜内转移诊断中的价值。资料与方法回顾性分析2010年10月—2022年4月于江西省人民医院行^(18)F-FDG PET/CT和MRI检查且确诊椎管内转移肿瘤患者的影像资料,对病灶代谢活性进行视觉分析,并测量最大标准化摄取值(SUVmax)。分析^(18)F-FDGPET/CT诊断硬脊膜内转移的敏感度、特异度和准确度,并应用受试者工作特征曲线分析SUVmax诊断硬脊膜内转移的效能。结果135例伴可疑椎管内转移症状的肿瘤患者中,硬脊膜内(软脊膜和髓内)转移18例,其他病变80例,脊髓无病变37例。18例硬脊膜内转移中,13例软脊膜转移,2例髓内转移,3例同时有软脊膜和髓内转移。转移表现为结节状(10例)或条片状(6例)18F-FDG摄取增高,对应CT上髓旁或髓内结节或脊髓肿胀。^(18)F-FDGPET/CT比MRI发现了更多的病灶,包括亚厘米的病灶。基于患者,^(18)F-FDGPET/CT诊断硬脊膜内转移的敏感度、特异度和准确度分别为88.9%、89.2%、89.1%;以转移灶和正常脊髓SUVmax进行受试者工作特征曲线分析显示,界值为2.45时约登指数最大,对应敏感度、特异度分别为88.2%、75.7%。结论18F-FDG PET/CT是诊断硬脊膜内转移的一种可选择影像模式。硬脊膜内转移大多数表现为局灶性高代谢病变,SUVmax可作为诊断硬脊膜内转移的一个有价值的参考指标。