FDG-PET versus Thallium-201 SPECT in the evaluation of putative CNS lymphoma in AIDS patients

1537 Background: The evaluation of CNS lesions in AIDS patients is challenging as both CNS lymphoma and non-neoplastic lesions can have similar clinical presentations and imaging findings. Both Tl-201 SPECT and FDG PET imaging have been used to differentiate malignancy from infection. This study investigates the accuracy of FDG PET compared to Tl-201 SPECT in the diagnosis of CNS lymphoma in patients with AIDS-associated CNS lesions. Methods: Nine patients with AIDS who were found to have rim enhancing brain lesions on MRI underwent both Tl-201 SPECT and FDG PET imaging prior to diagnosis. Diagnosis was made by stereotactic brain biopsy in 6 pts and clinical follow-up in the remaining 3. FDG PET of the brain was performed using a dedicated PET/CT instrument (GE Discovery) 1 hour after 444 MBq FDG. Brain SPECT was performed on a dual head gamma camera (GE Hawkeye) with 185 MBq Tl-201. Images were reviewed along with MRI for anatomic correlation by 2 experienced nuclear medicine physicians blinded to the diagnosis. Results: 43 MRI lesions in 9 patients were evaluated. Clinically, 5 pts (18 lesions) were diagnosed with lymphoma (4 biopsy proven, 1 with known history of lymphoma), and 4 pts (25 lesions) were diagnosed with toxoplasmosis (2 with negative biopsies for malignancy, 2 with clinical course consistent with toxoplasmosis). FDG PET had true positive results for lymphoma in 5 of 5 pts, while Tl-201 SPECT was true positive in only 2 of 5. FDG PET had true negative results in 4 of 4 pts with toxoplasmosis, while Tl-201 had false positive results in 2 of 4. FDG PET had positive and negative predictive values of 100%, while Tl-201 SPECT had PPV 50% and NPV 40%. On a lesion basis, PET showed increased uptake of FDG in 8 of 18 brain lesions in patients with lymphoma, while SPECT showed increased uptake of Tl-201 in 4 of 18 lesions. Tl-201 was positive in 2 lesions in patients diagnosed with toxoplasmosis, while FDG had no false positive lesions. Conclusion: In this limited study, FDG PET proved to be superior to Tl-201 SPECT in the differentiation of CNS lymphoma from toxoplasmosis (overall accuracy 100% vs 44%, respectively). With the increasing availability of FDG PET, this test should probably supplant Tl-201 SPECT as the study of choice following conventional imaging (CT, MRI) of CNS lesions in AIDS patients. No significant financial relationships to disclose.

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False-Negative and False-Positive Results in FDG-PET and PET/CT in Breast Cancer

PET Clinics ◽

10.1016/j.cpet.2009.09.002 ◽

2009 ◽

Vol 4 (3) ◽

pp. 289-298 ◽

Cited By ~ 10

Author(s):

Rakesh Kumar ◽

Neerja Rani ◽

Chetan Patel ◽

Sandip Basu ◽

Abass Alavi

Keyword(s):

Breast Cancer ◽

False Positive ◽

Fdg Pet ◽

False Negative ◽

Pet Ct ◽

Positive Results

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FDG PET Scan Alone Better Predicts Progression Free Survival at 2 Years Compared to CT Imaging in Aggressive Histology Non-Hodgkin’s Lymphoma Following Initial Anthracycline-Based Chemotherapy.

Blood ◽

10.1182/blood.v104.11.3299.3299 ◽

2004 ◽

Vol 104 (11) ◽

pp. 3299-3299 ◽

Cited By ~ 2

Author(s):

Gregory A. Wiseman ◽

Malik E. Juweid ◽

Eric M. Rohren ◽

James E. Wooldridge ◽

Michael M. Graham

Keyword(s):

Bone Marrow ◽

Tumor Cells ◽

Pet Imaging ◽

Fdg Pet ◽

Ct Imaging ◽

Pet Scan ◽

Predictive Values ◽

Viable Tumor ◽

Fdg Pet Scan ◽

Pet Scans

Abstract Background: CT imaging has routinely been used for assessing therapy response in most malignancies including Non-Hodgkins Lymphoma (NHL). The presence of residual tumor is generally categorized using the International Workshop Criteria from CT imaging and bone marrow biopsies for assessing response after treatment. CT imaging has limitations in assessment of response to therapy in NHL with false positive results due to residual masses having viable tumor cells in less than 20% and the remainder being fibrosis or necrosis. In addition false negative CT results are seen due to viable tumor cells in nodes measuring less than 1.5 cm in size. F-18 FDG PET scans provide metabolic imaging of viable tumor cells due to uptake and retention of F-18 fluorodeoxyglucose preferentially in malignant cells. Method: Forty-eight patients with aggressive NHL having completed anthracycline-based chemotherapy had the post therapy FDG PET scans and CT scans reviewed by experienced readers blinded from the comparison scan and from the clinical history. PET scans were read as positive or negative for abnormal FDG consistent with residual viable tumor and the CT was read as positive or negative for nodes greater than 1.5 cm in diameter. Records were reviewed for tumor histology and evidence of tumor relapse with a median follow-up of 35 months. Results: The FDG PET and CT imaging prediction of PFS at 2 years had positive predictive values of 67% and 38%, negative predictive values of 88% and 78%, and accuracy of 81% and 50% respectively. The sensitivity and specificity of the FDG PET scan was 71% and 82% for predicting disease progression within 2 years from beginning treatment. Conclusion: FDG PET imaging was compared with CT imaging done after completing initial chemotherapy for aggressive NHL and demonstrated superior prediction of tumor response status at 2 years. These results indicate that FDG PET imaging should be combined with bone marrow biopsy for restaging aggressive NHL after completion of chemotherapy. The use of FDG PET is more accurate and should replace response assessment by CT imaging in most pateints with aggressive NHL following treatment.

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Use of CT and MR imaging to distinguish intracranial lesions and to define the need for biopsy in AIDS patients

Journal of Neurosurgery ◽

10.3171/jns.1990.73.5.0720 ◽

1990 ◽

Vol 73 (5) ◽

pp. 720-724 ◽

Cited By ~ 130

Author(s):

Samuel F. Ciricillo ◽

Mark L. Rosenblum

Keyword(s):

Mr Imaging ◽

Primary Cns Lymphoma ◽

Signs And Symptoms ◽

Cns Lymphoma ◽

Mr Images ◽

Aids Patients ◽

Content Type ◽

Immunodeficiency Syndrome ◽

Mass Lesions ◽

Cns Lesions

✓ To explore the potential usefulness of imaging studies in the diagnosis of focal central nervous system (CNS) lesions associated with acquired immunodeficiency syndrome (AIDS), the authors retrospectively examined the radiographic studies of 149 AIDS patients who presented with signs and symptoms of the three most common focal CNS lesions. Of these patients, 74 (50%) had Toxoplasma abscesses, 45 (30%) had primary CNS lymphoma, and 30 patients (20%) had progressive multifocal leukoencephalopathy (PML). Magnetic resonance (MR) imaging was more sensitive than computerized tomography (CT) in detecting lesions, especially in cases of PML. Whereas CT was unable to distinguish mass lesions caused by toxoplasmosis from those caused by lymphoma, 71% of the solitary lesions seen on MR images were lymphomas. These results indicate that empirical treatment for toxoplasmosis, the most common initial treatment for AIDS patients with neurological symptoms stemming from mass lesions, is not likely to be successful for patients with solitary lesions on MR images. Rather, early biopsy is advisable. If the presence of lymphoma is confirmed, the rapid initiation of treatment can allow prolonged high-quality survival.

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FDG-PET for Staging and Follow-up of HIV-Infected Patients with Non Hodgkin Lymphoma and Hodgkin Lymphoma: A Single Center Experience.

Blood ◽

10.1182/blood.v114.22.5014.5014 ◽

2009 ◽

Vol 114 (22) ◽

pp. 5014-5014

Author(s):

Silvia Cantoni ◽

Erika Ravelli ◽

Maria Cristina Moioli ◽

Chiara Rusconi ◽

Vittorio Ruggero Zilioli ◽

...

Keyword(s):

Hiv Infection ◽

Ct Scan ◽

Hodgkin Lymphoma ◽

False Positive ◽

Fdg Pet ◽

False Negative ◽

Hiv Positive ◽

Number Of Patients ◽

Positive Results

Abstract Abstract 5014 Introduction Risk of developing non Hodgkin lymphomas (NHL) is known to be increased among patients (pts) infected by HIV-1 and sporadic non-HIV related cases of Hodgking lymphomas (HL) are also described. HIV-positive pts also feature a virus-related systemic lymphoadenopathy which makes nodal involvement by lymphoma difficult to evaluate using conventional imaging. The role of positron-emission tomography using 18F-fluorodeoxyglucose (FDG-PET) in the staging and evaluation of response to treatment of pts with NHL and HL is well established in immunocompetent pts, while only limited information is available on lymphomas arising in the setting of HIV infection. We report on a retrospective analysis of FDG-PET results in a group of HIV pts with lymphoma, both NHL and HL, followed-up at our hospital. Patients and methods Twelve HIV-positive male pts with a diagnosis of lymphoma (7 high grade and 1 follicular NHL, 4 HL) underwent a total of 22 PET scans. PET results were compared with those obtained by computed tomography (CT). Nine PET were performed at staging, 7 at restaging following chemotherapy, and 6 at follow-up. At diagnosis of lymphoma: median CD4 count was 200 cells/mcL (range 98-451); HIV genome was undetectable in 5/9 pts, in the remaining 4 pts for whom the data was available viral loads ranged from 103 to 1,452,720 copies/mL; 10/12 pts were already receiving HAART, while the remaining 2 pts started treatment upon diagnosis of lymphoma. Results In the majority of cases (17/22 = 77%) results of PET, CT scan and clinical status were concordant, being diagnostic of either lymphoma presence (11/17) or absence (6/17). No false positive results were recorded at follow-up. In 5/22 cases (23%) PET and CT scan were discordant. In 4 cases PET yielded a false negative result; in 2 cases at diagnosis (2 pts with HL) and in 2 cases at follow-up (both in the pt with follicular lymphoma). In the remaining case, a PET-negative CT-positive adenopathy was demonstrated which proved to be reactive in nature at biopsy. Discussion Our results suggest that FDG-PET is useful in the evaluation of lymphoma in the setting of HIV infection, similarly to what has been observed among immunocompetent pts. Although the number of patients is limited, in our experience PET proved to be able to discriminate between reactive and lymphomatous involvement of lymphoid tissue as demonstrated by absence of false positive results in pts evaluated at follow-up. These results need to be confirmed by larger clinical trials. Disclosures No relevant conflicts of interest to declare.

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An analysis of true- and false-positive results of vocal fold uptake in positron emission tomography-computed tomography imaging

The Journal of Laryngology & Otology ◽

10.1017/s002221511700247x ◽

2017 ◽

Vol 132 (3) ◽

pp. 270-274 ◽

Cited By ~ 3

Author(s):

N Seymour ◽

G Burkill ◽

M Harries

Keyword(s):

Computed Tomography ◽

Positron Emission Tomography ◽

Head And Neck ◽

False Positive ◽

Vocal Fold ◽

Emission Tomography ◽

True Positive ◽

Positron Emission ◽

Computed Tomography Scans ◽

Positive Results

AbstractObjectives:Positron emission tomography-computed tomography with fluorine-18 fluorodeoxy-D-glucose has a major role in the investigation of head and neck cancers. Fluorine-18 fluorodeoxy-D-glucose is not a tumour-specific tracer and can also accumulate in benign pathology. Therefore, positron emission tomography-computed tomography scan interpretation difficulties are common in the head and neck, which can produce false-positive results. This study aimed to investigate patients detected as having abnormal vocal fold uptake on fluorine-18 fluorodeoxy-D-glucose positron emission tomography-computed tomography.Methods:Positron emission tomography-computed tomography scans were identified over a 15-month period where reports contained evidence of unilateral vocal fold uptake or vocal fold pathology. Patients’ notes and laryngoscopy results were analysed.Results:Forty-six patients were identified as having abnormal vocal fold uptake on positron emission tomography-computed tomography. Twenty-three patients underwent positron emission tomography-computed tomography and flexible laryngoscopy: 61 per cent of patients had true-positive positron emission tomography-computed tomography scans and 39 per cent had false-positive scan results.Conclusion:Most patients referred to ENT for abnormal findings on positron emission tomography-computed tomography scans had true-positive findings. Asymmetrical fluorine-18 fluorodeoxy-D-glucose uptake should raise suspicion of vocal fold pathology, accepting a false-positive rate of approximately 40 per cent.

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Immunoscintigraphy with 131I or 111In Labelled OC 125 F(ab')2 Fragments in Patients with Ovarian Carcinoma

The International Journal of Biological Markers ◽

10.1177/172460089000500401 ◽

1990 ◽

Vol 5 (4) ◽

pp. 159-165 ◽

Cited By ~ 2

Author(s):

A. Jiménez-Vicioso ◽

M. Torres ◽

A. Jiménez-Heffernan ◽

M.D. Grana ◽

J.M. Latre ◽

...

Keyword(s):

Ovarian Carcinoma ◽

False Positive ◽

True Positive ◽

Recurrence Analysis ◽

Uterine Myomas ◽

Follicular Cyst ◽

S 100 ◽

B Uptake ◽

Positive Results

To evaluate the clinical usefulness of immunoscintigraphy with OC 125 in ovarian carcinoma, we studied 25 patients suspected of having ovarian carcinoma or in follow-up after surgery. Fourteen patients were studied with 131I-OC 125 F(ab')2 and 11 with 111In-OC 125 F(ab')2. No differences were observed with the use of either radionuclide. Global diagnostic indexes obtained were S = 100%, Sp = 44,5% and A = 81%. The low specificity obtained was remarkable: 5 false positive results in two uterine myomas, one abscess, one follicular cyst and one granulation tissue scar. On the other hand, all lesions of ovarian carcinoma were detected. Analysis of the evolution of tumor/background (T/B) uptake ratios from the first to the second day of exploration revealed a tendency for the ratio to diminish significantly (> 15%) in false positive cases with the exception of the abscess while this did not happen in true positive cases, with the exception of a regional recurrence. Analysis of T/B ratio variations could contribute towards elevating the test's specificity.

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Is the Remarkable Contradiction between Histology and 14C Urea Breath Test in the Detection of Helicobacter pylori due to False-negative Histology or False-positive 14C Urea Breath Test?

Journal of International Medical Research ◽

10.1177/147323000503300604 ◽

2005 ◽

Vol 33 (6) ◽

pp. 632-640 ◽

Cited By ~ 10

Author(s):

AK Gurbuz ◽

AM Ozel ◽

Y Narin ◽

Y Yazgan ◽

H Baloglu ◽

...

Keyword(s):

Helicobacter Pylori ◽

False Positive ◽

Breath Test ◽

False Negative ◽

Urea Breath Test ◽

Predictive Values ◽

Urease Test ◽

H Pylori ◽

Micro Organisms ◽

Positive Results

We assessed the diagnostic value of the 14C urea breath test (UBT) in the detection of Helicobacter pylori compared with histology and the rapid urease test (RUT). The study included 68 patients (22 men and 46 women) with dyspeptic symptoms. H. pylori status was evaluated by 14C UBT, RUT and histology. Sensitivity, specificity, positive and negative predictive values, and diagnostic accuracy were determined for 14C UBT and for RUT. Histology revealed dense yeast-like micro-organisms in the biopsy specimens in all patients with false-positive results by 14C UBT (n = 8), a significantly higher proportion than in patients with negative 14C UBT (five of 31). The low specificity of the H. pylori14C UBT should not be neglected by accepting histology results as false-negative. Gastric mucosal colonization by yeast-like micro-organisms with urease activity can account for the high frequency of false-positive results for 14C UBT.

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