Cold tuberculous abscess identified by FDG PET

Spine Infections: the role of Fluorodeoxyglucose Positron Emission Tomography (FDG PET) in the context of the actual diagnosis guideline

Spondylodiscitis is an infectious process that requires numerous health care professionals to be clearly diagnosed and eventually successfully treated. It implies a variety of microbiological agents and conditions; during the diagnostic workup, it is difficult to correctly identify them, and the clinician has to rapidly choose the correct treatment to avoid permanent injuries to the patient. In this context, we conducted a review to better understand the most suitable use of Positron Emission Tomography with 18-Fluoro-deossi-glucose (FDG PET) in a patient suspected of spondylodiscitis, based on current guidelines and literature.. We wanted to review the role of FDG PET in the spondylodiscitis diagnosis and follow up in the context of the current guidelines.

Comparison of the Diagnostic Value of MRI and Whole Body 18F-FDG PET/CT in Diagnosis of Spondylodiscitis

Spondylodiscitis is a spine infection for which a diagnosis by a magnetic resonance imaging (MRI) is considered the most appropriate imaging technique. The aim of this study was to compare the role of an ¹⁸F-fluorodeoxyglucose positron emission tomography/computed tomography (¹⁸F-FDG PET/CT) and an MRI in this field. For 56 patients with suspected spondylodiscitis for whom MRI and ¹⁸F-FDG PET/CT were performed, we retrospectively analyzed the results. Cohen’s κ was applied to evaluate the agreement between the two techniques in all patients and in subgroups with a different number of spinal districts analyzed by the MRI. Sensitivity, specificity, and accuracy were also evaluated. The agreements of the ¹⁸F-FDG PET/CT and MRI in the evaluation of the entire population, whole-spine MRI, and two-districts MRI were moderate (κ = 0.456, κ = 0.432, and κ = 0.429, respectively). In patients for whom one-district MRI was performed, ¹⁸F-FDG PET/CT and MRI were both positive and completely concordant (κ = 1). We also separately evaluated patients with suspected spondylodiscitis caused by Mycobacterium tuberculosis for whom the MRI and ¹⁸F-FDG PET/CT were always concordant excepting in 2 of the 18 (11%) patients. Sensitivity, specificity, and accuracy of the MRI and ¹⁸F-FDG PET/CT were 100%, 60%, 97%, and 92%, 100%, and 94%, respectively. Our results confirmed the ¹⁸F-FDG PET/CT diagnostic value in the diagnosis of spondylodiscitis is comparable to that of MRI for the entire spine evaluation. This could be considered a complementary technique or a valid alternative to MRI.

18F-Fluorodeoxyglucose positron emission tomography and infectious diseases: current applications and future perspectives

PURPOSE OF REVIEW

18F-Fluorodeoxyglucose positron emission tomography/computed tomography is a well-established technique for diagnosis and management of a number of neoplastic conditions. However, in recent years the body of literature regarding its potential role in infectious diseases has progressively increased, with promising results.

RECENT FINDINGS

So far 18F-fluorodeoxyglucose positron emission tomography/computed tomography has a well-established role and is recommended by guidelines only in a few settings, such as prosthetic valve endocarditis, vascular device infections, and chronic osteomyelitis. However, even the lack of large, prospective randomized trials, an increasing number of small series and case reports suggest a potential role in the diagnosis, disease staging, and monitoring of treatment response of several other infective conditions.

SUMMARY

In this article, we summarize the available evidence and potential future applications of 18F-fluorodeoxyglucose positron emission tomography/computed tomography in the diagnosis and management of infectious diseases.

Radionuclide Imaging of Infection and Inflammation in Children: a Review

With the exception of radiolabeled monoclonal antibodies, antibody fragments and radiolabeled peptides which have seen little application in the pediatric population, the nuclear medicine imaging procedures used in the evaluation of infection and inflammation are the same for both adults and children. These procedures include (1) either a two- or a three-phase bone scan using technetium-99m methylene diphosphonate; (2) Gallium 67-citrate; (3) in vitro radiolabeled white blood cell imaging (using ¹¹¹Indium-oxine or ^99mTechnetium hexamethyl-propylene-amine-oxime-labeled white blood cells); and (4) hybrid imaging with ¹⁸F-FDG. But children are not just small adults. Not only are the disease processes encountered in children different from those in adults, but there are developmental variants that can mimic, but should not be confused with, pathology. This article discusses some of the differences between adults and children with osteomyelitis, illustrates several of the common developmental variants that can mimic disease, and, finally, focuses on the increasing use of ¹⁸F-FDG PET/CT in the diagnosis and response monitoring of children with infectious and inflammatory processes. The value of and need for pediatric specific imaging protocols are reviewed.

PET/CT in nononcological lung diseases: current applications and future perspectives

Positron emission tomography (PET) combined with computed tomography (CT) is an established diagnostic modality that has become an essential imaging tool in oncological practice. However, thanks to its noninvasive nature and its capability to provide physiological information, the main applications of this technique have significantly expanded.(18)F-labelled fluorodeoxyglucose (FDG) is the most commonly used radiopharmaceutical for PET scanning and demonstrates metabolic activity in various tissues. Since activated inflammatory cells, like malignant cells, predominantly metabolise glucose as a source of energy and increase expression of glucose transporters when activated, FDG-PET/CT can be successfully used to detect and monitor a variety of lung diseases, such as infections and several inflammatory conditions.The added value of FDG-PET/CT as a molecular imaging technique relies on its capability to identify disease in very early stages, long before the appearance of structural changes detectable by conventional imaging. Furthermore, by detecting the active phase of infectious or inflammatory processes, disease progression and treatment efficacy can be monitored.This review will focus on the clinical use of FDG-PET/CT in nonmalignant pulmonary diseases.

Radiologic Responses in Cynomolgus Macaques for Assessing Tuberculosis Chemotherapy Regimens

Trials to test new drugs currently in development against tuberculosis in humans are impractical. All animal models to prioritize new regimens are imperfect, but nonhuman primates (NHPs) infected with Mycobacterium tuberculosis develop active tuberculosis (TB) disease with a full spectrum of lesion types seen in humans. Serial 2-deoxy-2-[¹⁸F]-fluoro-d-glucose (FDG) positron emission tomography (PET) with computed tomography (CT) imaging was performed on cynomolgus macaques during infection and chemotherapy with individual agents or the four-drug combination therapy most widely used globally. The size and metabolic activity of lung granulomas varied among animals and even within a single animal during development of disease. Individual granulomas within untreated animals had highly local and independent outcomes, some progressing in size and FDG uptake, while others waned, illustrating the highly dynamic nature of active TB. At necropsy, even untreated animals were found to have a proportion of sterile lesions consistent with the dynamics of this infection. A more marked reduction in overall metabolic activity in the lungs (decreased FDG uptake) was associated with effective treatment. A reduction in the size of individual lesions correlated with a lower bacterial burden at necropsy. Isoniazid treatment was associated with a transient increase in metabolic activity in individual lesions, whereas a net reduction occurred in most lesions from rifampin-treated animals. Quadruple-drug therapy resulted in the highest decrease in FDG uptake. The findings of PET-CT imaging may provide an important early correlate of the efficacy of novel combinations of new drugs that can be directly translated to human clinical trials.

Monitoring Therapeutic Response in a Case of Extrapulmonary Tuberculosis by Serial F-18 FDG PET/CT

Due to the low yield of AFB smear and culture in extrapulmonary tuberculosis, therapeutic responses of patients with extrapulmonary tuberculosis are usually monitored clinically and/or radiographically. Such monitoring techniques, however, are not enough to provide effective diagnosis if a remnant lesion exists after treatment. Tuberculosis presents hypermetabolic activity on F-18 fluorodeoxyglucose positron emission tomography/computed tomography (F-18 FDG PET/CT) scanning. Reported herein is a case of extrapulmonary tuberculosis where the therapeutic response was assessed via serial F-18 FDG PET/CT scanning, which was useful for detecting the extent of extrapulmonary tuberculosis and for estimating the patient's therapeutic response.

Combined PET and X-ray computed tomography imaging in pulmonary infections and inflammation

PURPOSE OF REVIEW

This review addresses issues relating to the use of the relatively new combined PET and X-ray computed tomography (PET/CT) modality for imaging pulmonary infections and inflammation, as well as assessing its potential for this purpose.

RECENT FINDINGS

Accurate definition and monitoring of the extent of lung infection is difficult using conventional chest radiograph, CT scan, MRI, and radioisotope scintigraphy. In the last decade, PET/CT using radiolabeled fluorodeoxyglucose has been added to the imaging armamentarium, mostly for imaging lung cancer. To date, very few data are available on the application of this technique for imaging pulmonary infections and inflammation; however, this situation is changing, and there is now more interest in using PET/CT for this purpose. In addition, there are new tracers on the horizon which remain to be exploited.

SUMMARY

This review addresses some of these issues and outlines the potential to use PET/CT for noncancer pulmonary indications.

Clinical impact of (18)F-FDG PET/CT on the management and diagnosis of infectious spondylitis

OBJECTIVE

The aim of this study was to evaluate the impact of (18)F-fluorodeoxyglucose (FDG) positron emission tomography (PET)/computed tomography (CT) on the management of patients with infectious spondylitis.

MATERIALS AND METHODS

Twenty-nine patients with infectious spondylitis (9 with tuberculous spondylitis and 20 with pyogenic spondylitis) who had undergone an (18)F-FDG PET/CT examination were retrospectively evaluated; 42 lesions were detected. A useful impact on the clinical management of infection therapy (start or longer duration of antibiotic therapy, or surgical intervention, etc) was defined as a strong impact, whereas gaining new information not affecting the clinical management of infection therapy from (18)F-FDG PET/CT was defined as a weak impact. No impact was defined as not obtaining any new information influencing infection therapy.

RESULTS

(18)F-FDG PET/CT had a strong impact on the clinical management of 52% (15 of 29) of the patients. (18)F-FDG PET/CT detected 10 cases of spondylitis and one artificial graft infection that the clinician had not recognized, and the therapeutic period was extended in these patients. In five patients with tuberculous spondylitis, the (18)F-FDG PET/CT images were used to decide the biopsy sites in three patients and to determine which lesions required surgery in two patients.

CONCLUSION

(18)F-FDG PET/CT is useful for detecting infectious spondylitis.

A female presenting with prolonged fever, weakness, and pain in the bilateral pelvic region: a case report

Introduction

Psoas abscess, a collection of pus in the iliopsoas compartment that has traditionally been classified as primary and secondary according to its origin.

Case presentation

48-year-old Turkish female presented to the department with fever, weakness and pain in the bilateral pelvic region. In contrast abdominal magnetic resonance, a collection compatible with the hyperintense abscess was observed in the right and left ilipsoas muscles. It was decided to simultaneously drain both abscesses of the case who had been using oral and intravenous broad-spectrum antibiotics for two months. No factors were detected in the microbiological reviews made on the abscess fluid of the operated case. The case was also examined in terms of tuberculosis and Crohn's disease and no findings were encountered to rise suspicions of such diseases.

Conclusion

An abscess of the psoas muscle was a rare entity. However, with the increased use of computed tomography scans to evaluate patients with unknown foci of sepsis, psoas abscesses now are diagnosed and reported more frequently. What should be done after diagnosis are, if possible, defining the infection factor, selecting the appropriate antibiotics and draining the abscess openly or percutaneously.

Postoperative abdominal aspergilloma mimicking cervical cancer recurrence and diagnostic imaging, including F-fluorodeoxyglucose positron emission tomography, with false-positive findings

We present the case of a 39-year-old woman with a subfascial abscess. The patient had undergone radical hysterectomy for stage Ib1 cervical cancer. Six months after the surgery, she was found to have an elevated concentration of the serum squamous cell carcinoma antigen. Thereafter, she underwent magnetic resonance imaging and positron emission tomography-computed tomography. Magnetic resonance imaging revealed an irregular mass (diameter: 2 cm) in the abdominal wall. Increased (18)F-fluorodeoxyglucose uptake into the mass was observed on positron emission tomography. Therefore, we could not rule out the possibility of the peritoneal dissemination of cervical cancer, and we resected the mass. The mass was pathologically and microbiologically diagnosed as a subfascial aspergilloma. The lesion was located in the subfascial area where a drain was inserted at the time of the primary laparotomy.

Systemic disseminated tuberculosis mimicking malignancy on F-18 FDG PET-CT

FDG PET-CT imaging is increasingly accepted as a modality for evaluation of many malignancies, but FDG also can be accumulated intensely by inflammatory lesions. We present a case of a 60-year-old woman with intermittent fever, chills, fatigue, and dyschezia. CT scans indicated colon carcinoma with thoracic and retroperitoneal lymph node metastases. Whole body FDG PET-CT was performed to confirm and stage the malignant disease and showed intense FDG uptake in those lesions. However, histopathology confirmed tuberculosis. The literature describing FDG accumulation in constitutional tuberculous lesions is sparse, and one must be aware of patterns of FDG accumulation in tuberculosis in the diagnosing malignancies.

Mycobacterium tuberculosis infection in patients with cancer, the role of 18-fluorodeoxyglucose positron emission tomography for diagnosis and monitoring treatment response

Active tuberculosis (TB) infection including asymptomatic and extrapulmonary disease may be detected with 18-fluorodeoxyglucose positron emission tomography/computed tomography (FDG-PET/CT). This report highlights the promising role of FDG-PET/CT for evaluation of TB in high-risk, immunocompromised patients with cancer. PET/CT performed for cancer evaluation may detect asymptomatic infection and guide definitive diagnosis. It may also be a useful tool in the assessment of latent TB, to exclude active disease prior to treatment. PET/CT has potential for monitoring response to anti-tuberculosis treatment. Metabolic response may indicate clinical response and guide duration of anti-microbial therapy.