肺内淋巴瘤的PET/CT影像表现分型

目的 总结恶性淋巴瘤(ML)肺侵犯的PET/CT影像学表现类型和特点,为正确诊断提供依据.方法 78例有肺侵犯的ML患者均经病理活组织检查证实,其中非霍奇金淋巴瘤(NHL)47例,霍奇金淋巴瘤(HL)10例,病理分型不明确的淋巴瘤21例.31例是因诊断不明确而;行PET/CT检查,发现并经病理检查确诊为ML,另47例已明确诊断者行PET/CT检查以了解肿瘤全身侵犯情况或有无复发、评价疗效.分析所有患者的PET/CT影像表现.结果 ML肺侵犯的影像表现形式各异,且同一病例可以同时出现不同的病变类型,大致可分为:(1)结节及肿块型(46例,含7例空洞型);(2)纤维索条及斑片型(29例);(3)胸膜心包侵犯型(23例);(4)双肺弥漫型(12例);(5)节段性或全肺不张型(9例);(6)环绕支气管肺门型(7例).除全身淋巴结组织和肺侵犯以外,还有其他部位的累及:骨皮质和骨髓内5例,胃3例,皮下软组织3例,乳腺1例,肾1例,肝1例,喉部1例.结论 PET/CT可以较准确地发现ML对肺的侵犯,显示病灶大小、形态和分布及肿瘤活性,为淋巴瘤的诊断和准确分期提供帮助.     

PET/CT and renal pathology: a blind spot for radiologists? Part 2--lymphoma, leukemia, and metastatic disease

OBJECTIVE: PET/CT with (18)F-FDG is a powerful tool to evaluate patients with hematologic malignancy or to assess the burden of metastatic disease from solid tumors. Metabolically active renal pathology associated with lymphoma, leukemia, or metastatic disease can be missed without close attention to both the PET and CT portions of the study because of physiologic FDG excretion in the kidneys. This article illustrates the appearance of tracer uptake and the key anatomic features of lymphoma, leukemia, and metastatic disease involving the kidney on FDG PET/CT. CONCLUSION: Close attention to both the FDG PET and CT portions of an FDG PET/CT study is essential to evaluate the kidneys in oncology patients.     

F-18 FDG PET/CT evaluation of radiotherapy response in rare case of mucosa-associated lymphoid tissue lymphoma

We experienced two cases of mucosa-associated lymphoid tissue (MALT) lymphoma arising at unusual locations and used F-18 fluorodeoxyglucose (FDG) positron emission tomography/computed tomography (PET/CT) to evaluate their response to radiation therapy (RT). A 62-year-old male with proven prostatic MALT lymphoma and a 43-year-old woman with proven duodenal MALT lymphoma had diffuse FDG uptake in the lesion. Both cases were treated with RT; following FDG, PET/CT showed decreased FDG uptake in each lesion. Neither patient had evidence of recurrence at more than 18 months after RT. FDG PET/CT is useful for indicating the treatment site in MALT lymphoma and in evaluation of therapeutic response following RT.     

Clinical role of FDG PET/CT for methotrexate-related malignant lymphoma

Methotrexate-related malignant lymphoma (MTX-RML) is a type of therapy-related lymphoma, and it often occurs in patients with rheumatoid arthritis. The most distinctive characteristic of MTX-RML is a quick response to withdrawal of MTX. However, because there is a risk of recurrence without a distinctive indicator of disease, close follow-up is needed. We present F-18 2-fluoro-2-deoxyglucose (FDG) postitron emission tomography (PET) or computed tomography (CT) images of MTX-RML along with the characteristic clinical presentation of MTX-RML. FDG PET/CT has the advantage of being able to detect malignant lymphoma in patients who have undergone MTX treatment. After withdrawal of MTX, FDG uptake decreases along with a reduction in the volume of lesions. Although recurrent lesion develops independent to the initial FDG PET/CT findings, FDG PET/CT is useful for early detection of unexpected recurrent lesions. FDG PET/CT allows for the assessment of malignant lymphoma and recurrent lesions in patients who received MTX therapy, which is crucial for the management of MTX-RML.     

胃恶性淋巴瘤的18F-FDG PET/CT表现与鉴别诊断

目的:分析胃淋巴瘤的18F-FDG PET/CT影像学特点,探讨其在胃淋巴瘤的诊断、鉴别诊断和病情评估中的价值。方法:17例经胃镜活检病理证实的胃淋巴瘤患者,包括13例弥漫性大B细胞淋巴瘤,3例粘膜相关淋巴组织B细胞淋巴瘤和1例NK/T细胞淋巴瘤,均在治疗前行PET/CT显像。结果:胃淋巴瘤的PET/CT表现以不同形式的胃壁增厚和显著增高的FDG代谢为主要特征,6例呈Ⅰ型表现(胃壁弥漫性增厚伴FDG代谢显著增高),7例呈Ⅱ型表现(胃壁节段性增厚伴FDG代谢显著增高),3例呈Ⅲ型表现(胃壁局限性增厚伴FDG代谢增高),1例呈Ⅳ型表现(胃壁多发结节样增厚伴FDG代谢串珠样增高);PET/CT评价4例仅累及胃壁,3例累及胃壁和淋巴结,10例累及胃壁、淋巴结和其它脏器。结论:胃淋巴瘤的18F-FDG PET/CT表现以Ⅰ型和Ⅱ型更为多见;18F-FDG PET/CT有助于淋巴瘤的诊断和病情全面评估。     

Primary peripheral T-cell lymphoma of the colon mimics inflammatory bowel disease: a potential pitfall with F-18 FDG PET/CT imaging

We present a case of a woman with ulcerative colitis who was referred for an F-18 FDG PET/CT after a suspicious colonoscopy and biopsy. PET/CT showed multiple elongated foci of intense FDG uptake in the colon, a pattern commonly reported with inflammatory bowel disease; however, the possibility of lymphoma was raised. Reevaluation of the biopsies with immunohistochemistry and molecular studies revealed a peripheral T-cell lymphoma and the patient was treated with a total colectomy. In this case, F-18 FDG PET/CT was very useful in determining the extent of the disease. This case also highlights a potential pitfall whereby the tubular and multifocal appearance of this lymphoma subtype can mimic the appearance of bowel involved by inflammatory bowel disease especially on novel techniques such as PET/CT enterography and PET/CT colonography.     

The impact of fluorodeoxyglucose-positron emission tomography in primary staging and patient management in lymphoma patients

Fully diagnostic positron emission tomography (PET)/CT scans acquired during oral and intravenous contrast can be provided to patients and referring physicians in a single imaging session. Although FDG uptake varies, most low-grade lymphomas exhibit sufficient FDG avidity to also be staged reliably with FDG PET/CT. PET/CT imaging is more accurate for lymphoma staging than PET or CT alone and has substantial impact on patient management. This accurate whole-body glucose metabolic survey should serve as the baseline for subsequent treatment response evaluations. PET/CT has evolved to become the modality of choice for staging of nodal and extranodal lymphoma, for assessing therapeutic response, and for establishing patient prognosis.     

惰性淋巴瘤大细胞转化的~(18)F-FDG PET/CT影像研究(附8例分析)

目的:探讨~(18)F-FDG PET/CT对惰性淋巴瘤大细胞转化的诊断价值.方法:回顾性分析8例惰性淋巴瘤转化前后~(18)F-FDG PET/CT影像,其中男性5例,女性3例,平均年龄53.5岁;8例转化前后均经病理及免疫组化染色证实.结果:8例惰性淋巴瘤最终均转化为弥漫大B细胞型淋巴瘤;其中6例由黏膜相关淋巴组织边缘区B细胞淋巴瘤(MALT)转化;1例由滤泡性淋巴瘤(FL)转化;1例由霍奇金结节性淋巴细胞为主性淋巴瘤(NLPHL)转化.转化前病灶~(18)F-FDG摄取呈轻度增高或无增高,平均SUV为2.2±1.0;转化后病灶~(18)F-FDG摄取明显增高,平均SUV为4.7±1.9;转化后病灶平均SUV明显高于转化前(P<0.01).结论:惰性淋巴瘤以小细胞为主,其增殖活性低,核分裂不明显,葡萄糖代谢水平较低,在PET/CT上病灶呈低摄取;转化成大细胞淋巴瘤增殖活性高,核分裂明显,葡萄糖代谢水平明显增高,提示~(18)F-FDG PET/CT随访可帮助判断惰性淋巴瘤发生大细胞转化.     

Normal and abnormal patterns of 18F-fluorodeoxyglucose PET/CT in lymphoma

In spite of the high performance of 18F-fluorodeoxyglucose (FDG) PET for the evaluation of lymphoma, inherent limitations of this modality underscore the additional value of PET/CT as an important tool in the assessment of this disease. Accumulating data on the use of PET/CT in lymphoma indicate the contribution of hybrid imaging to improved interpretation accuracy of PET using FDG and CT. Knowledge of the normal and abnormal patterns of FDG-PET/CT imaging and their variability in patients with lymphoma is important to provide a comprehensive clinically significant interpretation that has an impact on patient management and potentially on outcome.     

Nonossifying fibroma can mimic residual lymphoma in FDG PET: additional value of combined PET/CT

A 12-year-old girl was diagnosed with Hodgkin's lymphoma and underwent conventional cross-sectional imaging for initial staging. Chemotherapy was given according to standard pediatric protocols. At the end of therapy, an F-18 FDG PET/CT examination was performed to evaluate the therapeutic response. The scan demonstrated focal uptake of FDG in the right distal femur and residual lymphoma was taken into consideration. However, findings in the coregistered CT scan were consistent with nonossfiying fibroma, a common benign skeletal lesion. Combined PET/CT imaging can be helpful to identify benign bone lesions mimicking metastatic or residual disease in F-18 FDG PET as illustrated by this case.     

Nodal staging of lymphoma with whole-body PET: comparison of.

Accurate staging is elementary for optimal management of malignant lymphoma. Advanced cases may be curable with multidrug chemotherapy combined with radiotherapy, whereas limited disease can sometimes be cured by local radiotherapy only. Recently, FDG imaging with whole-body PET (WB PET) has been introduced as an accurate method for staging lymphoma. We evaluated the usefulness of L-[methyl-11C]methionine (MET) in comparison with FDG as a tracer for nodal staging of lymphoma with WB PET. METHODS: Nineteen patients with untreated, histologically proven malignant lymphoma underwent WB PET imaging with MET and FDG within 1 wk before treatment. Fourteen patients had non-Hodgkin's lymphoma (NHL), and 5 had Hodgkin's disease (HD). Two of these 19 patients were excluded from the final analysis because of hyperglycemia. WB PET images using FDG and MET were visually compared by 3 independent interpreters, and the PET findings were correlated with the data on the basis of conventional staging studies. RESULTS: Fifty-five of 178 lymph node regions were classified as diseased both by FDG PET and by CT, and 54 of 178 were classified as diseased both by MET PET and by CT. In addition, 11 lymph node regions that CT showed to be normal avidly accumulated FDG. Ten of these lymph node regions also had clear uptake of MET. Another 4 and 5 lymph node regions were enlarged at CT but were judged to be normal by FDG and MET PET, respectively. In nodal staging, both FDG PET and MET PET would have upstaged the disease in 3 patients. MET PET would also have downstaged the disease in 1 patient. CONCLUSION: FDG and MET seem to be comparable in the detection of lymphoma by WB PET. However, visual interpretation of the images tends to be hampered more by physiologic accumulations of MET than by normal accumulations of FDG, and MET may be preferable to FDG in hyperglycemic patients undergoing staging studies with PET.     

Fat necrosis mimicking B-cell lymphoma: a PET/CT and FDG study

F-18 fluoro-2-deoxyglucose positron emission tomography combined with computed tomography (FDG and PET/CT) is increasingly becoming the standard in staging and restaging patients with a range of malignancies including B-cell lymphoma. However, there are well-known pitfalls in PET/CT with FDG imaging, which comprise infection, inflammation, physiological variants, and benign pathologic conditions. Fat necrosis is the result of death of adipose tissue from disease, injury, or pathologic conditions. We describe a case of false positive PET/CT and FDG scan in a patient with fat necrosis mimicking B-cell lymphoma after 6 cycles of rituximab with cyclophosphamide, doxorubicin, vincristine, and prednisone (R-CHOP) treatment. In interpreting PET/CT and FDG images with inconsistency in lesion response, fat necrosis should be considered in the differential diagnosis.     

Acute varicella infection mimics recurrent Hodgkin's disease on F-18 FDG PET/CT

We report a case where acute varicella infection, chickenpox, mimics the findings of recurrent Hodgkin disease on F-18 FDG PET/CT. A 28-year-old man with a history of Hodgkin disease in remission had fatigue, pyrexia, and a raised ESR. His F-18 FDG PET/CT, performed to exclude lymphoma recurrence, demonstrated FDG-avid lymphadenopathy and increased FDG uptake in his spleen. A day later he developed the generalized rash of acute varicella infection. This was managed with valacyclovir. Repeat F-18 FDG PET/CT done 1 month later showed no evidence of FDG-avid disease. In this patient the stimulation of an immune response by the acute viral infection mimics recurrent lymphoma.     

Direct comparison of FDG PET and CT findings in patients with lymphoma: initial experience

PURPOSE: To retrospectively compare fluorine 18 fluorodeoxyglucose (FDG) positron emission tomographic (PET) and computed tomographic (CT) findings at the same anatomic locations in patients with lymphoma by using a combined PET/CT scanner and to analyze the lesions on metabolic and anatomic bases to evaluate causes of discrepant findings between the two modalities. MATERIALS AND METHODS: The institutional review board allowed an exempt retrospective review of cancer PET database, and informed consent was waived. The study was HIPAA compliant. Fifty-three patients with lymphoma (20 Hodgkin and 33 non-Hodgkin; mean age, 43 years; range, 12-83 years) who underwent FDG PET/CT were included. The PET and CT images were interpreted by two nuclear medicine physicians and one radiologist, respectively, blinded to the other imaging findings. Concordant PET and CT findings were regarded as positive or negative for lymphoma. The site with discordant findings was defined as positive for disease if it was accompanied by other PET- and CT-positive sites in the same patient or was confirmed clinically (histologic examination or progressive disease). Staging results were also compared by one nuclear medicine physician. RESULTS: Of a total of 1537 anatomic sites in 53 patients, 48 had discordant findings between PET and CT. Forty (83%) of the 48 sites had correct PET findings (31 positive, nine negative), five had correct CT findings, and three were unresolved. The 31 PET-positive and CT-negative sites accounted for 23% of all 134 true-positive PET sites. PET provided accurate staging in an incremental nine (17%, upstaging in four and downstaging in five) of 53 patients in whom CT staging was incorrect. CT provided correct upstaging in two patients. CONCLUSION: FDG PET/CT as a combined modality may contribute substantially to lesion characterization and staging in patients with lymphoma.     

The management of pyothorax-associated lymphoma using <Superscript>18</Superscript>F-FDG PET/CT

Objective  

Pyothorax-associated lymphoma (PAL) is a rare form of lymphoma and its management on ¹⁸F-fluorodeoxyglucose (FDG) positron emission tomography (PET) combined computed tomography (CT) has not been well reported. The purpose of this study was to evaluate the usefulness of FDG PET/CT in patients with PAL.     

Role of F-18 FDG PET/CT in assessing bone marrow involvement in pediatric Hodgkin’s lymphoma

Objectives

The aim of the current study was to assess the utility of F-18-fluoro-2-deoxy-d-glucose (F-18 FDG) positron emission tomography/computed tomography (PET/CT) in assessing bone marrow involvement (BMI) compared to bone marrow biopsy (BMB) in initial staging of Hodgkin’s lymphoma (HL) in pediatric patients.

Methods

Data of 38 pediatric patients (mean age 9.8 years, range 3–18 years) with HL were analyzed for the involvement of bone marrow. All patients underwent non-contrast F-18 FDG PET/CT study. BMB was done in 31 patients from the bilateral iliac crests. Scans were interpreted by two nuclear medicine physicians blinded to the details of BMB.

Results

Of the 31 patients who underwent BMB, 5 patients had lymphomatous involvement on BMB. PET/CT was positive in four of these five patients. In 26 patients negative on BMB, PET was negative in 23 patients and positive in 3 patients for BMI. The sensitivity and negative predictive value of F-18 FDG PET/CT was 87.5 and 96 %, respectively, for BMI.

Conclusions

F-18 FDG PET/CT can predict BMB results with high accuracy. F-18 FDG PET/CT may be used at initial staging of pediatric Hodgkin’s lymphoma as it uncovers unsuspected BMI and BMB may be omitted in patients with PET-positive BMI.     

False-Positive FDG PET/CT Due to Liver Parenchymal Injury Caused By a Surgical Retractor

ABSTRACT: A 70-year-old man underwent partial gastrectomy with pathology demonstrating gastric follicular lymphoma. After surgery, a staging FDG PET/CT study demonstrated an FDG-avid low-attenuation band in the liver. Corresponding MRI demonstrated a high T2 signal abnormality. This was believed to represent liver parenchymal injury due to liver retraction during surgery. The patient was managed conservatively. MRI at 1 month of follow-up demonstrated resolution of the T2 signal abnormality. FDG PET/CT at 6 months of follow-up demonstrated resolution of FDG uptake. Tissue injury from surgical retraction can produce FDG-avid lesions that need to be distinguished from malignancy on PET/CT.     

^18F-FDG PET-CT在淋巴瘤分期及疗效评价中的应用研究

目的探讨^18氟-氟代脱氧葡萄糖（^18F-FDG）PET—CT在淋巴瘤分期及疗效评价中的临床应用价值。方法回顾分析28例淋巴瘤患者（HL6例，NHL22例）在治疗前后进行^18F—FDG PET—CT对比检查的结果，并与增强CT及骨髓活检结果进行比较。结果治疗前68处病灶^18F—FDG PET—CT检出67个，检出率为98．5％，其中结内37个全部检出（100％），结外31个检出30个（96．8％）；增强CT则共检出病灶45个（66．2％），其中结内37个检出32个（86．5％），结外31个仅检出13个（41．9％）。6例（21．4％）的分期得到上调并改变了1例（3．6％）的治疗方案。治疗后32处病灶^18F—FDG PET—CT检出29个，检出率为90．6％，其中结内17个检出15个（88．2％），结外15个检出14个（93．3％）；增强CT则共检出病灶18个（56．3％），其中结内17个检出13个（76．5％）．结外15个仅检出5个（33．3％）。治疗后有2例（7．1％）的分期得到上调，8例（28．6％）下调，改变了8例（21．4％）的治疗方案。^18F—FDG PET—CT对淋巴瘤患者治疗前后结内病灶检出率与增强CT相似（P〈0．05），而结外病灶检出率则明显高于增强CT（P〉0．05）。28例中25例^18F—FDG PET—CT与骨髓穿刺结果一致。治疗后^18F—FDG PET—CT对复发的阳性预测值93．8％，阴性预测值为83．3％；增强CT的阳性预测值75％，阴性预测值50％。结论^18F—FDG PET—CT在淋巴瘤分期及疗效评价中具有重要的临床价值．有助于准确分期和残余病变性质的鉴别。     

FDG PET CT assessment of treatment response after yttrium-90 ibritumomab tiuxetan radioimmunotherapy

Yttrium-90 ibritumomab tiuxetan (Zevalin; IDEC Pharmaceuticals Corp., San Diego, CA) is the first radioimmunotherapy agent approved by the U.S. Food and Drug Administration (FDA) for treatment of non-Hodgkin lymphoma. In a randomized clinical trial comparing Zevalin with rituximab, the overall response rate was 80% and 56%, respectively. Response was determined by assessing the size of lymph nodes on CT scans. FDG PET has been well accepted as an accurate imaging study for staging non-Hodgkin lymphoma and evaluating response to treatment. Simultaneous FDG PET and CT imaging (PET CT) provides coregistered functional PET images with anatomic CT images. We describe 2 cases of non-Hodgkin lymphoma treated in which response was followed using PET CT.     

FDG PET can replace bone scintigraphy in primary staging of malignant lymphoma.

Recent studies indicated that 18F-fluorodeoxyglucose (FDG) PET may be more accurate than CT in staging nodal and extranodal malignant lymphoma. The objective of this study was to compare conventional bone scintigraphy as an established skeletal staging procedure with PET using FDG in the detection of osseous involvement in malignant lymphoma. METHODS: Whole-body PET-based staging studies of 56 consecutive patients with proven Hodgkin's disease (n = 34) or non-Hodgkin's lymphoma (n = 22) were compared with the results of bone scintigraphy. Positive PET or bone scintigraphic findings were confirmed, if possible, by biopsy, MRI, CT or radiographic investigations. RESULTS: Of the 56 patients studied, 12 were found to have skeletal involvement on both studies (PET, 30 regions; bone scintigraphy, 20 regions). Findings were confirmed in all 12 patients. FDG PET detected an additional 12 involved regions in 5 patients. This was subsequently verified in 3 patients, although the other 2 cases remained unresolved. Conversely, bone scintigraphy revealed five abnormalities compatible with lymphoma in 5 patients. Three of these lesions were found to be erroneous; final evaluation of the remaining two findings was not possible. CONCLUSION: FDG PET is suitable for identifying osseous involvement in malignant lymphoma with a high positive predictive value and is thereby more sensitive and specific than bone scintigraphy.