Application of Nuclear Medicine Techniques in Musculoskeletal Infection: Current Trends and Future Prospects.

Nuclear medicine has become an indispensable discipline in the diagnosis and management of musculoskeletal infections. Radionuclide tests serve as a valuable diagnostic tool for patients suspected of having osteomyelitis, spondylodiscitis, or prosthetic joint infections. The choice of the most suitable imaging modality depends on various factors, including the affected area, potential extra osseous involvement, or the impact of previous bone/joint conditions. This review provides an update on the use of conventional radionuclide imaging tests and recent advancements in fusion imaging scans for the differential diagnosis of musculoskeletal infections. Furthermore, it examines the role of radionuclide scans in monitoring treatment responses and explores current trends in their application. We anticipate that this update will be of significant interest to internists, rheumatologists, radiologists, orthopedic surgeons, rehabilitation physicians, and other specialists involved in musculoskeletal pathology.

Imaging of Multiple Myeloma: Present and Future.

Multiple myeloma (MM) is the second most common adult hematologic malignancy, and early intervention increases survival in asymptomatic high-risk patients. Imaging is crucial for the diagnosis and follow-up of MM, as the detection of bone and bone marrow lesions often dictates the decision to start treatment. Low-dose whole-body computed tomography (CT) is the modality of choice for the initial assessment, and dual-energy CT is a developing technique with the potential for detecting non-lytic marrow infiltration and evaluating the response to treatment. Magnetic resonance imaging (MRI) is more sensitive and specific than 18F-fluorodeoxyglucose positron emission tomography/computed tomography (FDG-PET/CT) for the detection of small focal lesions and diffuse marrow infiltration. However, FDG-PET/CT is recommended as the modality of choice for follow-up. Recently, diffusion-weighted MRI has become a new technique for the quantitative assessment of disease burden and therapy response. Although not widespread, we address current proposals for structured reporting to promote standardization and diminish variations. This review provides an up-to-date overview of MM imaging, indications, advantages, limitations, and recommended reporting of each technique. We also cover the main differential diagnosis and pitfalls and discuss the ongoing controversies and future directions, such as PET-MRI and artificial intelligence.

Chondroid Tumors: Review of Salient Imaging Features and Update on the WHO Classification.

Chondrogenic tumors are typically well recognized on radiographs, but differentiation between benign and malignant cartilaginous lesions can be difficult both for the radiologist and for the pathologist. Diagnosis is based on a combination of clinical, radiological and histological findings. While treatment of benign lesions does not require surgery, the only curative treatment for chondrosarcoma is resection. This article (1) emphasizes the update of the WHO classification and its diagnostic and clinical effects; (2) describes the imaging features of the various types of cartilaginous tumors, highlighting findings that can help differentiate benign from malignant lesions; (3) presents differential diagnoses; and (4) provides pathologic correlation. We attempt to offer valuable clues in the approach to this vast entity.

Myxomas and myxoid liposarcomas of the extremities: Our preliminary findings in conventional, perfusion, and diffusion magnetic resonance.

Background: The differentiation between myxomas and myxoid liposarcomas (MLPS) often is a serious challenge for the radiologists. Magnetic resonance imaging (MRI) is the most useful imaging technique in characterization of the soft tissue tumors (STT). Purpose: To evaluate in a sample of myxomas and MLPS of the extremities, what morphological findings in conventional MRI allow us to differentiate these two types of myxoid tumors, in addition to analyzing the validity of the apparent diffusion coefficient (ADC) values of diffusion-weighted MRI (DW-MRI). Material and Methods: Magnetic resonance imaging studies in myxomas and MLPS of extremities searched in our PACS between 2015 and 2019. All studies had conventional MRI with T1, T2, and PD SPAIR sequences, while DW-MRI with ADC mapping and perfusion MRI with a T1 sequence repeated for 4 minutes after contrast injection were additional sequences only in some explorations. Two radiologists evaluated independently the MRI studies by examining the qualitative parameters. Apparent diffusion coefficient values were calculated using two methods-ADC global and ADC solid, and Receiver Operating Characteristic (ROC) curves were applied for analysis. Results: The features were consistent with MLPS: size greater than 10 cm, heterogeneous signal on T1, and nodular enhancement, while the common findings for myxomas were a homogenously hypointense signal on T1 and diffuse peritumoral enhancement. The solid and global ADC values were higher in myxomas. We observed that the solid ADC value less than 2.06 x 10-3mm2 x s would support the diagnosis of MLPS against myxoma. Conclusion: Overall, MRI with its different modalities improved the diagnostic accuracy when differentiating myxomas from MLPS of extremities.

Agreement Between 18F-FDG PET/CT and Whole-Body Magnetic Resonance Compared With Skeletal Survey for Initial Staging and Response at End-of-Treatment Evaluation of Patients With Multiple Myeloma.

PURPOSE: To compare the agreement between whole-body (WB) magnetic resonance (MR) imaging, 18F-FDG PET/CT, and skeletal survey (SS) in patients with multiple myeloma (MM) for diagnosis, initial staging, response evaluation, and early detection of complications. METHODS: This is a retrospective cohort study including MM patients who were diagnosed, treated, and followed in 2 institutions. These patients were studied with SS, WB-MR, and/or 18F-FDG PET/CT. We studied bone lesions by anatomical locations and analyzed the concordance between SS and a tomographic technique (WB-MR or 18F-FDG PET/CT) and between both tomographic techniques (WB-MR and PET/CT). RESULTS: Forty-four MM patients with a mean age of 62.6 years (range, 38-85 years) were included from January 2012 to February 2016. Whole-body MR and 18F-FDG PET/CT found more lesions than SS in every location except in the skull. Concordance between WB-MR and 18F-FDG PET/CT was either good or excellent in most of the locations and in plasmacytoma studies. However, WB-MR was better than 18F-FDG PET/CT in the study of complications (medullar compression and vascular necrosis). CONCLUSIONS: Our results suggest the study of MM patients should include WB-MR and/or 18F-FDG PET/CT, whereas SS is only useful for the skull. Whole-body MR and 18F-FDG PET/CT are complementary techniques, because both of them show good concordance in almost every location. It is still necessary to individualize the indication of each technique according to patient characteristics.

Evaluación de la estadificación inicial y la respuesta final al tratamiento de los pacientes con linfoma difuso de célula grande B con la tomografía computarizada de 64 detectores frente a la 18FDG tomografía por emisión de positrones/tomografía computarizada / Evaluation of diffuse large B-cell lymphoma patients with 64-slice multidetector computed tomography versus 18FDG positron emission tomography/computed tomography in initial staging and restaging after treatment

Fundamento y objetivos: Comparar prospectivamente la exactitud diagnóstica de la tomografía computarizada de 64 detectores (TCMD64) y la tomografía por emisión de positrones/tomografía computarizada (18FDG PET/TC) con contraste intravenoso en pacientes con linfoma difuso de células grandes B (LDCGB) en la estadificación inicial y en la evaluación de la respuesta al final del tratamiento. Material y métodos: Ensayo clínico controlado multicéntrico que incluyó 72 pacientes de 5 hospitales de la Comunidad de Madrid entre enero de 2012 y junio de 2015, aleatorizados de forma ciega a una diferente prueba de imagen inicial y final, 36 a 18FDG PET/TC y 36 a TCMD64. Un médico nuclear y un radiólogo interpretaron la 18FDG PET/TC de manera independiente, llegando a un consenso post-hoc. Por otro lado, un radiólogo ajeno interpretó la TCMD64 por separado. El patrón de referencia incluyó datos clínicos, pruebas complementarias y seguimiento. El Comité Ético de cada hospital aprobó el estudio y los sujetos firmaron su consentimiento por escrito. Resultados: Se observó buena concordancia de ambas pruebas diagnósticas con el patrón de referencia en la estadificación inicial (18FDG PET/CT [k=0,5] y TCMD64 [k=0,6]), existiendo solo buena concordancia en la evaluación de la respuesta al final del tratamiento con la 18FDG PET/TC (k=0,7). Conclusión: En la estadificación inicial de pacientes con LDCGB existe un grado de acuerdo satisfactorio de la 18FDG PET/TC y la TCMD64 con el patrón de referencia, mientras que en la evaluación de la respuesta al final del tratamiento la 18FDG PET/TC es superior a la TCMD64

Background and objectives: To prospectively compare the accuracy in initial staging and end-of-treatment restaging of diffuse large B-cell lymphoma (DLBCL) between 64-slice multidetector computed tomography (64MDCT) and 18FDG positron emission tomography/computed tomography (18FGD PET/CT) with intravenous contrast injection. Material and methods: Randomised and blind controlled clinical multicentric trial that included biopsy-proven DLBCL patients. Seventy-two patients from five different hospitals in the region of Madrid, Spain, were enrolled in the study between January 2012 and June 2015. Thirty-six were randomly allocated to 18FDG PET/TC and the other 36 to 64MDCT for initial staging and end-of-treatment restaging. A nuclear medicine physician and a radiologist independently analysed 18FDG PET/TC images and reached an agreement post-hoc. 64MDCT images were separately evaluated by a different radiologist. Every set of images was compared to the reference standard that included clinical data, complementary tests and follow-up. The study was approved by participating centres’ ethics committees and written informed consent was obtained from all the participants. Results: A good agreement was observed between both diagnostic techniques and the reference standard in initial staging [18FDG PET/CT (k=0.5) and 64MDCT (k=0.6)], although only the 18FDG PET/TC showed a good agreement with the reference standard for the end-of-treatment restaging (k=0.7). Conclusion: In DLBCL, both 18FDG PET/TC and 64MDCT have shown good agreement with the reference standard in initial staging. Nevertheless, 18FDG PET/CT has shown to be superior to 64MDCT in end-of-treatment response assessment

Skeletal muscle and solitary bone metastases from malignant melanoma: multimodality imaging and oncological outcome.

Malignant melanoma solitary metastases to bone or skeletal muscle occur in 0.8% of patients. The aim of this study was to evaluate features of skeleton and muscle metastases with multimodality imaging and review the oncological outcome. Thirteen patients with melanoma metastases from January 2006 to February 2016 were included. Histologic confirmation was obtained. Imaging studies included computed tomography (CT), MRI, and/or positron emission tomography/CT. Treatment received and BRAF status were recorded. Differences in BRAF status and overall survival (OS) were analyzed using the χ-test. Associations between OS and metastases were analyzed using Cox proportional models. Nine (69%) patients showed osseous involvement. Lower extremity bones were affected in three (23%) patients: first toe, right calcaneal spurs, and knee. The spine was involved in three (23%) patients. In two (15%) patients, the pelvic bones were involved. In one (8%) patient, the temporal bone was affected. Nine (70%) patients had a history of malignant melanoma, with a median time to progression of 28 months. The median OS was 18 months: 24 months in patients with a history of melanoma and 3 months in patients with metastases at first diagnosis. The median follow-up duration was 28 months. BRAF mutant versus wild-type tumors showed significant differences in OS (P=0.03). The hazard ratio for death in the metastatic group at diagnosis was 6.83, 95% confidence interval: 1.060-144.072 (P=0.04). Solitary metastases from melanoma to the skeleton and muscle are rare. CT, MRI, and positron emission tomography/CT are useful for the evaluation of musculoskeletal findings. Image findings are not definitive for diagnosing a malignant solitary lesion; thus, a pathologic confirmation with a biopsy is recommended.

Evaluation of diffuse large B-cell lymphoma patients with 64-slice multidetector computed tomography versus 18FDG positron emission tomography/computed tomography in initial staging and restaging after treatment. / Evaluación de la estadificación inicial y la respuesta final al tratamiento de los pacientes con linfoma difuso de célula grande B con la tomografía computarizada de 64 detectores frente a la 18FDG tomografía por emisión de positrones/tomografía computarizada.

BACKGROUND AND OBJECTIVES: To prospectively compare the accuracy in initial staging and end-of-treatment restaging of diffuse large B-cell lymphoma (DLBCL) between 64-slice multidetector computed tomography (64MDCT) and 18FDG positron emission tomography/computed tomography (18FGD PET/CT) with intravenous contrast injection. MATERIAL AND METHODS: Randomised and blind controlled clinical multicentric trial that included biopsy-proven DLBCL patients. Seventy-two patients from five different hospitals in the region of Madrid, Spain, were enrolled in the study between January 2012 and June 2015. Thirty-six were randomly allocated to 18FDG PET/TC and the other 36 to 64MDCT for initial staging and end-of-treatment restaging. A nuclear medicine physician and a radiologist independently analysed 18FDG PET/TC images and reached an agreement post-hoc. 64MDCT images were separately evaluated by a different radiologist. Every set of images was compared to the reference standard that included clinical data, complementary tests and follow-up. The study was approved by participating centres' ethics committees and written informed consent was obtained from all the participants. RESULTS: A good agreement was observed between both diagnostic techniques and the reference standard in initial staging [18FDG PET/CT (k=0.5) and 64MDCT (k=0.6)], although only the 18FDG PET/TC showed a good agreement with the reference standard for the end-of-treatment restaging (k=0.7). CONCLUSION: In DLBCL, both 18FDG PET/TC and 64MDCT have shown good agreement with the reference standard in initial staging. Nevertheless, 18FDG PET/CT has shown to be superior to 64MDCT in end-of-treatment response assessment.

Compresión medular dorsal por tofos gotosos: presentación de un caso y revisión de la bibliografía / Medullar thoracic compression by tophaceous gout: presentation of a case and review of the literature

Introducción. La afectación de la columna vertebral en la gota es una complicación extremadamente infrecuente. La dorsalgia y la cuadriplejía son algunas manifestaciones que se pueden presentar, aunque estos síntomas se ven con más frecuencia en otras patologías más prevalentes, como los tumores medulares. Caso clínico. Se presenta un caso inusual de compresión medular dorsal en D10-D11 causado por el depósito extradural de material tofáceo en una paciente de 52 años con gota tofácea crónica incontrolada. Además de un tratamiento médico intensivo, la paciente requirió cirugía (hemilaminectomía y descompresión medular) y rehabilitación posterior. La evolución general y neurológica fue satisfactoria (AU)

Introduction. Spine involvement in gout is an extremely uncommon complication. Dorsalgia and quadriplegia are some manifestations that may occur, although these symptoms are seen more frequently in other more prevalent pathologies, such as spinal tumors. Case report. We present an unusual case of thoracic spinal cord compression at T10-T11 level caused by the extradural deposit of tophaceous material in a 52-year-old woman with uncontrolled chronic tophaceous gout. In addition to intensive medical treatment, the patient required surgery (hemilaminectomy and spinal decompression) and subsequent rehabilitation. Overall and neurological evolution were satisfactory (AU)

Structural similarity index family for image quality assessment in radiological images.

The structural similarity index (SSIM) family is a set of metrics that has demonstrated good agreement with human observers in tasks using reference images. These metrics analyze the viewing distance, edge information between the reference and the test images, changed and preserved edges, textures, and structural similarity of the images. Eight metrics based on that family are proposed. This new set of metrics, together with another eight well-known SSIM family metrics, was tested to predict human performance in some specific tasks closely related to the evaluation of radiological medical images. We used a database of radiological images, comprising different acquisition techniques (MRI and plain films). This database was distorted with different types of distortions (Gaussian blur, noise, etc.) and different levels of degradation. These images were analyzed by a board of radiologists with a double-stimulus methodology, and their results were compared with those obtained from the 16 metrics analyzed and proposed in this research. Our experimental results showed that the readings of human observers were sensitive to the changes and preservation of the edge information between the reference and test images, changes and preservation in the texture, structural component of the images, and simulation of multiple viewing distances. These results showed that several metrics that apply this multifactorial approach (4-G-SSIM, 4-MS-G-SSIM, [Formula: see text], and [Formula: see text]) can be used as good surrogates of a radiologist to analyze the medical quality of an image in an environment with a reference image.

Multicenter Comparison of Contrast-Enhanced FDG PET/CT and 64-Slice Multi-Detector-Row CT for Initial Staging and Response Evaluation at the End of Treatment in Patients With Lymphoma.

OBJECTIVES: To compare staging correctness between contrast-enhanced FDG PET/ceCT and 64-slice multi-detector-row CT (ceCT64) for initial staging and response evaluation at the end of treatment (EOT) in patients with Hodgkin lymphoma, diffuse large B cell lymphoma (DLBCL), and follicular lymphoma. METHODS: This prospective study compared initial staging and response evaluation at EOT. One hundred eighty-one patients were randomly assigned to either ceCT64 or FDG PET/ceCT. A nuclear medicine physician and a radiologist read FDG PET/ceCT scans independently and achieved post hoc consensus, whereas another independent radiologist interpreted ceCT64 separately. The reference standard included all clinical information, all tests, and follow-up. Ethics committees of the participating centers approved the study, and all participants provided written consent. RESULTS: Ninety-one patients were randomized to ceCT64 and 90 to FDG PET/ceCT; 72 had Hodgkin lymphoma, 72 had DLBCL, and 37 had follicular lymphoma. There was excellent correlation between the reference standard and initial staging for both FDG PET/ceCT (κ = 0.96) and ceCT64 (κ = 0.84), although evaluation of the response at EOT was excellent only for FDG PET/ceCT (κ = 0.91). CONCLUSIONS: Our study demonstrated satisfactory agreement between FDG PET/ceCT (κ = 0.96) and ceCT64 (κ = 0.84) in initial staging compared with the reference standard (P = 0.16). Response evaluation at EOT with FDG PET/ceCT (κ = 0.91) was superior compared with ceCT64 (κ = 0.307) (P < 0.001).

Vasoactive Intestinal Peptide in Early Spondyloarthritis: Low Serum Levels as a Potential Biomarker for Disease Severity.

Spondyloarthritis (SpA) is a family of inflammatory diseases sharing clinical, genetic, and radiological features. While crucial for tailoring early interventions, validated prognostic biomarkers are scarce in SpA. We analyze the correlation between serum levels of vasoactive intestinal peptide (VIP) and disease activity/severity in patients with early chronic inflammatory back pain. The study population comprised 54 patients enrolled in our early chronic inflammatory back pain register. We collected demographic information, clinical data, laboratory data, and imaging findings. VIP levels were measured by enzyme immunoassay in serum samples from 162 visits. The association between independent variables and VIP levels was analyzed using longitudinal multivariate analysis nested by patient and visit. No significant differences were observed in VIP levels between these two groups. Lower levels of VIP were significantly associated with a higher Bath Ankylosing Spondylitis Disease Activity Index (BASFI) score, presence of bone edema in magnetic resonance imaging (MRI) scan, and lower hemoglobin levels. Coexistence of cutaneous psoriasis was independently associated with lower VIP levels, and similar trend was observed for enthesitis. We conclude that SpA patients with low serum VIP levels had worse 2-year disease outcome, suggesting that serum VIP levels could be a valid prognostic biomarker.

(18)F-fluorodeoxyglucose positron emission tomography/computed tomography accuracy in the staging of non-small cell lung cancer: review and cost-effectiveness.

Aim of the performed clinical study was to compare the accuracy and cost-effectiveness of PET/CT in the staging of non-small cell lung cancer (NSCLC). Material and Methods. Cross-sectional and prospective study including 103 patients with histologically confirmed NSCLC. All patients were examined using PET/CT with intravenous contrast medium. Those with disease stage ≤IIB underwent surgery (n = 40). Disease stage was confirmed based on histology results, which were compared with those of PET/CT and positron emission tomography (PET) and computed tomography (CT) separately. 63 patients classified with ≥IIIA disease stage by PET/CT did not undergo surgery. The cost-effectiveness of PET/CT for disease classification was examined using a decision tree analysis. Results. Compared with histology, the accuracy of PET/CT for disease staging has a positive predictive value of 80%, a negative predictive value of 95%, a sensitivity of 94%, and a specificity of 82%. For PET alone, these values are 53%, 66%, 60%, and 50%, whereas for CT alone they are 68%, 86%, 76%, and 72%, respectively. Incremental cost-effectiveness of PET/CT over CT alone was €17,412 quality-adjusted life-year (QALY). Conclusion. In our clinical study, PET/CT using intravenous contrast medium was an accurate and cost-effective method for staging of patients with NSCLC.

Estadificación de los linfomas no hodgkinianos: estudio prospectivo de la tomografía por emisión de positrones/tomografía computarizada (PET/TC) frente a la PET y a la TC / Non-Hodgkin's lymphoma staging: a prospective study of the value of positron emission tomography/computed tomography (PET/CT) versus PET and CT

Fundamento y objetivo: Analizar prospectivamente la precisión de la tomografía por emisión de positrones/tomografía computarizada (PET/TC) frente al patrón oro en la estadificación inicial de los pacientes con linfoma no hodgkiniano (LNH) e identificar el protocolo técnico más adecuado.Pacientes y método: Estudio transversal prospectivo de 76 pacientes diagnosticados de LNH durante 3 años consecutivos en el Hospital Universitario La Paz de Madrid no tratados previamente. Todos los pacientes fueron estudiados con la técnica PET/TC: inicialmente se obtuvo una TC de dosis baja, después el escáner de emisión de la PET y posteriormente un estudio de TC de dosis alta con contraste intravenoso. Se reconstruyeron dos estudios de PET/TC para cada paciente: uno de PET/TC de dosis baja (PET/TC DB) y otro de PET/TC de dosis alta (PET/TC DA). Cada modalidad de PET/TC fue evaluada en consenso por un equipo de médico nuclear y radiólogo, diferente para cada una de las modalidades. Las imágenes de TC y de PET fueron interpretadas por separado por otro radiólogo y otro médico nuclear independientes.Resultados: La concordancia con el patrón de referencia fue en el 52,2% de los pacientes (κ=0,458) para la TC, 46% para la PET (κ=0,335), 75% para la PET/TC DB (κ=0,664) y 76,8% para la PET/TC DA (κ=0,679), con p<0,001. Todas las técnicas infravaloraron el estadio (p<0,05), aunque con la PET/TC DA en un menor porcentaje de pacientes (20,3%). Conclusión: La PET/TC es superior en la estadificación inicial de los pacientes con LNH, siendo la PET/TC DA la técnica más precisa de las que hemos estudiado (AU)

Background and objective: To prospectively analyze the diagnostic accuracy of PET/CT in non-Hodgkin's lymphoma (NHL) and to evaluate the most appropriate study protocol of this technique.Patients and method: Seventy-six biopsy proven NHL patients were enrolled in this prospective study for 3 years. Patients initially underwent a low-dose CT without intravenous contrast, then a PET emission scan and finally a full-dose CT with intravenous contrast. For every patient, two modalities of PET/CT images were reconstructed: a low-dose unenhanced PET/CT and a full-dose enhanced PET/CT. Each modality was evaluated by either of two pairs of readers, different for each modality. Enhanced CT and PET images were evaluated by an independent radiologist and nuclear medicine physician respectively.Results: Agreement between reference standard and techniques was as follows: 52.2% of patients with enhanced CT (κ=0.458), 46% with PET (κ=0.335), 75% with low-dose unenhanced PET/CT (κ=0.664) and 76.8% with full-dose enhanced PET/CT (κ=0.679), with p<0.001. Although all techniques underestimated the stage in comparison to gold standard, the lowest percentage was for full-dose enhanced PET/CT (20.3%).Conclusions: PET/CT improved staging accuracy of NHL, being full-dose enhanced PET/CT the most accurate technique in our study (AU)

[Non-Hodgkin's lymphoma staging: a prospective study of the value of positron emission tomography/computed tomography (PET/CT) versus PET and CT]. / Estadificación de los linfomas no hodgkinianos: estudio prospectivo de la tomografía por emisión de positrones/tomografía computarizada (PET/TC) frente a la PET y a la TC.

BACKGROUND AND OBJECTIVE: To prospectively analyze the diagnostic accuracy of PET/CT in non-Hodgkin's lymphoma (NHL) and to evaluate the most appropriate study protocol of this technique. PATIENTS AND METHOD: Seventy-six biopsy proven NHL patients were enrolled in this prospective study for 3 years. Patients initially underwent a low-dose CT without intravenous contrast, then a PET emission scan and finally a full-dose CT with intravenous contrast. For every patient, two modalities of PET/CT images were reconstructed: a low-dose unenhanced PET/CT and a full-dose enhanced PET/CT. Each modality was evaluated by either of two pairs of readers, different for each modality. Enhanced CT and PET images were evaluated by an independent radiologist and nuclear medicine physician respectively. RESULTS: Agreement between reference standard and techniques was as follows: 52.2% of patients with enhanced CT (κ=0.458), 46% with PET (κ=0.335), 75% with low-dose unenhanced PET/CT (κ=0.664) and 76.8% with full-dose enhanced PET/CT (κ=0.679), with p<0.001. Although all techniques underestimated the stage in comparison to gold standard, the lowest percentage was for full-dose enhanced PET/CT (20.3%). CONCLUSIONS: PET/CT improved staging accuracy of NHL, being full-dose enhanced PET/CT the most accurate technique in our study.

Integrated FDG PET/CT: Utility and Applications in Clinical Oncology.

Accurate diagnosis and staging are essential for an optimal management of cancer patients. Positron emision tomography with 2-deoxy-2-fluorine-18-fluoro-D-glucose ((18)FDG-PET) and, more recently, (18)FDG-PET/computed tomography ((18)FDG-PET/CT) have emerged as powerful imaging tools in oncology, because of the valuable functional information they provide. The combined acquisition of PET and CT has synergistic advantages over its isolated constituents and minimizes their limitations. It decreases examination times by 25%-40%, leads to a higher patient throughput and unificates two imaging procedures in a single session. There is evidence that (18)FDG-PET/CT is a more accurate test than either of its components for the evaluation of various tumors. It is a particularly valuable tool for detection of recurrence, especially in asymptomatic patients with rising tumor markers and those with negative or equivocal findings on conventional imaging tests. Yet, there are some limitations and areas of uncertainty, mainly regarding the lack of specificity of the (18)FDG uptake and the variable (18)FDG avidity of some cancers. This article reviews the advantages, limitations and main applications of (18)FDG-PET/CT in oncology, with especial emphasis on lung cancer, colorectal cancer, lymphomas, melanoma and head and neck cancers.

Blast injuries from Madrid terrorist bombing attacks on March 11, 2004.

Blast injuries after terrorist attacks are seen with increasing frequency worldwide. Thousands of victims were attended in the hospitals of Madrid, Spain, on March 11, 2004 after the bombing attacks against the commuter trains. Thirty-six patients were attended in our institution. Seventeen of them suffered from severe or life-threatening injuries, and 19 had mild injuries. The most common lesions were thoracic trauma and blast lung injury, acoustic trauma, and orbital and paranasal sinus fractures. Other findings were hepatic and splenic lacerations, and vertebral and limb fractures. Emergency radiology had an important role in the correct management of the victims. Prompt radiological diagnoses of these complex lesions are crucial to efficient treatment. Therefore, radiologists have to become familiar with the injury patterns and specific lesions caused by blast wave.

PET/CT in lymphoma: prospective study of enhanced full-dose PET/CT versus unenhanced low-dose PET/CT.

UNLABELLED: PET/CT combines functional and morphologic data and increases diagnostic accuracy in a variety of malignancies. This study prospectively compares the agreement between contrast-enhanced full-dose PET/CT and unenhanced low-dose PET/CT in lesion detection and initial staging of Hodgkin's disease and non-Hodgkin's lymphoma. METHODS: Forty-seven biopsy-proven lymphoma patients underwent a 18F-FDG PET/CT study that included unenhanced low-dose CT and enhanced full-dose CT for initial staging. Patients who had undergone previous diagnostic CT for initial staging were excluded. For every patient, each modality of PET/CT images was evaluated by either of 2 pairs of readers, with each pair comprising 1 experienced radiologist and 1 experienced nuclear physician. While evaluating one of the 2 types of PET/CT, the readers were unaware of the results of the other type. Lesion detection, number of sites affected in each anatomic region, and disease stage were assessed. Agreement between techniques was determined by the kappa-statistic, and discordances were studied by the McNemar test. Clinical, analytic, histopathologic, diagnostic CT, and PET data; data from other imaging techniques; and follow-up data constituted the reference standard. RESULTS: For region-based analysis, no significant differences were found between unenhanced low-dose PET/CT and contrast-enhanced full-dose PET/CT, although full-dose PET/CT showed fewer indeterminate findings and a higher number of extranodal sites affected than did low-dose PET/CT. Agreement between the 2 types of PET/CT was almost perfect for disease stage (kappa = 0.92; P < 0.001). CONCLUSION: Our study showed a good correlation between unenhanced low-dose PET/CT and contrast-enhanced full-dose PET/CT for lymph node and extranodal disease in lymphomas, suggesting that unenhanced low-dose PET/CT might suffice in most patients as the only imaging technique for the initial staging of lymphomas, reserving diagnostic CT for selected cases.

Positron emission tomography/computed tomography: diagnostic accuracy in lymphoma.

An accurate initial staging of patients with non-Hodgkin lymphoma (NHL) and Hodgkin lymphoma (HL) is critical for the selection of an appropriate treatment. Computed tomography (CT) remains the standard imaging technique, although it is based on anatomic criteria. Positron emission tomography (PET) with 2-deoxy-2-[fluorine-18]fluoro-d-glucose (FDG) provides useful functional information but requires anatomical correlation to localise lesions accurately. We have prospectively compared the accuracy of combined PET/CT with that of CT and PET alone at initial staging in lymphoma patients. Forty-seven newly diagnosed patients were evaluated. PET/CT was superior compared with CT and PET in nodal evaluation and detection of extranodal disease. Using a staging algorithm with PET/CT resulted in the disease stage being increased in 11 of 47 patients (10 NHL and 1 HL) (McNemar test P = 0.012). Therefore, a different treatment strategy based on PET/CT findings was suggested for seven patients (14.8%). PET/CT markedly improves accuracy in the diagnostic work-up of patients with lymphoma.

Positron emission tomography/computed tomography in the management of Hodgkin's disease and non-Hodgkin's lymphoma.

The incidence of Hodgkin's disease (HD) and Non-Hodgkin's lymphoma (NHL) is around 8% of all malignancies. Fortunately, HD and NHL are among the few malignancies that are potentially curable with current existing treatment modalities, even in advanced or recurrent disease. Accurate staging, early therapy monitoring, and posttreatment evaluation of lymphomas are important for optimum management of these patients. We reviewed the imaging findings of patients with histologically proved lymphoma who underwent staging positron emission tomography/computed tomography (PET/CT), early monitoring therapy PET/CT (after 3 cycles of chemotherapy), and posttreatment PET/CT. PET/CT imaging findings are shown. Utility of PET/CT in recognizing false-positive and false-negative cases of CT and PET alone is addressed. Pitfalls and diagnostic difficulties are analyzed. PET/CT is a new imaging technology that improves the evaluation of lymphoma. This review will help the reader to better understand the imaging findings and applications of PET/CT in the management of lymphoma.