Fabio Maggi

Lung Abnormalities at Multimodality Imaging after Radiation Therapy for Non–Small Cell Lung Cancer

Three-dimensional (3D) conformal radiation therapy (CRT) and stereotactic body radiation therapy (SBRT) are designed to deliver the maximum therapeutic radiation dose to the tumor, allowing improved local disease control, while minimizing irradiation of surrounding normal structures. The complex configuration of the multiple beams that deliver the radiation dose to the tumor in 3D CRT and SBRT produces patterns of lung injury that differ in location and extent from those seen after conventional radiation therapy. Radiation-induced changes in lung tissue after 3D CRT and SBRT occur within the radiation portals. The imaging appearance of irradiated tissues varies according to the time elapsed after the completion of therapy, with acute-phase changes of radiation pneumonitis represented by ground-glass opacities and consolidation and with late-phase changes of radiation fibrosis manifesting as volume loss, consolidation, and traction bronchiectasis. Knowledge of treatment timelines and radiation field locations, as well as familiarity with the full spectrum of possible radiation-induced lung injuries after 3D CRT and SBRT, is important to correctly interpret the abnormalities that may be seen at computed tomography (CT). Differential diagnoses in this context might include infections, lymphangitic carcinomatosis, local recurrence of malignancy, and radiation-induced tumors. The integration of morphologic information obtained at CT with metabolic information obtained at positron emission tomography is helpful in distinguishing radiation-induced parenchymal abnormalities from residual, recurrent, and new cancers. Thus, multimodality follow-up imaging may lead to substantial changes in disease management.

Usefulness of Whole-Body Fluorine-18-Fluorodeoxyglucose Positron Emission Tomography in Patients with Neurofibromatosis Type 1: A Systematic Review

Aim. To systematically review the role of positron emission tomography (PET) with fluorine-18-fluorodeoxyglucose (FDG) in patients with neurofibromatosis type 1 (NF1). Methods. A comprehensive literature search of published studies regarding FDG-PET and PET/CT in patients with NF1 was performed. No beginning date limit and language restriction were used; the search was updated until December 2011. Only those studies or subsets in studies including whole-body FDG-PET or PET/CT scans performed in patients with NF1 were included. Results. We identified 12 studies including 352 NF1 patients. Qualitative evaluation was performed in about half of the studies and semiquantitative analysis, mainly based on different values of SUV cutoff, in the others. Most of the studies evaluated the role of FDG-PET for differentiating benign from malignant peripheral nerve sheath tumors (MPNSTs). Malignant lesions were detected with a sensitivity ranging between 100% and 89%, but with lower specificity, ranging between 100% and 72%. Moreover, FDG-PET seems to be an important imaging modality for predicting the progression to MPNST and the outcome in patients with MPNST. Two studies evaluated the role of FDG-PET in pediatric patients with NF1. Conclusions. FDG-PET and PET/CT are useful methods to identify malignant change in neurogenic tumors in NF1 and to discriminate malignant from benign neurogenic lesions.

Is there a role for fluorine 18 fluorodeoxyglucose-positron emission tomography and positron emission tomography/computed tomography in evaluating patients with mycobacteriosis? A systematic review.

Objective: This study was designed to review the emerging role of fluorine 18 fluorodeoxyglucose (18F-FDG)-positron emission tomography (PET) CT/computed tomography (PET/CT) in patients with mycobacteriosis. Methods: A comprehensive literature search of published studies through October 2010 in PubMed/MEDLINE database regarding 18F-FDG-PET and PET/CT in patients with mycobacteriosis was performed. Results: Ultimately, we identified 16 studies comprising a total of 220 patients with mycobacteriosis. Main findings of the included studies are presented. Conclusions: (1) Mycobacteriosis commonly causes increased 18F-FDG uptake; therefore, positive 18F-FDG-PET results should be interpreted with caution in differentiating benign from malignant abnormalities. (2) 18F-FDG-PET and PET/CT are potentially useful in detecting sites of Mycobacterium infection. (3) Dual-phase 18F-FDG-PET is not useful for the differential diagnosis between malignant lesions and sites of Mycobacterium infection. (4) 18F-FDG-PET and PET/CT are useful for the evaluation of disease activity and in monitoring response to therapy in patients with mycobacteriosis. (5) Dual-tracer PET and PET/CT are potentially useful for presumptive diagnosis of solitary pulmonary nodules.

Automated volumetry of pulmonary nodules on multidetector CT: influence of slice thickness, reconstruction algorithm and tube current. Preliminary results

PurposeTo evaluate the influence of slice thickness, reconstruction algorithm and tube current (mA) on the performance of a software package in determining the volume of solid pulmonary nodules on multidetector-row computed tomography (MDCT).Materials and methodsA chest phantom containing artificial solid nodules with known volume was imaged with two MDCT scans at 100 and 40 mAs (200 mA and 80 mA, 0.5-s rotation time), respectively. Data were reconstructed with slice thicknesses of 1.25 and 2.5 mm and five different algorithms. The volumes of three nodules (juxtavascular, intraparenchymal, juxtapleural) were calculated using three-dimensional (3D) volumetric software. Differences between estimated and real volume were reported for each nodule and reconstruction set.ResultsThe software segmented all nodules on 1.25-mmthick reconstructions, independently from the mAs. It did not segment the juxtapleural nodule on 2.5-mm-thick reconstructions at 40 mAs. Mean values of the differences, which better approximated the real volume of the nodules, were obtained with high-spatial-resolution algorithms on both 100 and 40 mAs images at 1.25-mm slice thickness.ConclusionsSlice thickness, reconstruction algorithm and tube current can affect the 3D volume measurement of solid nodules. The best performance of the software, on both 100 and 40 mAs images, was observed with a slice thickness of 1.25 mm and high-spatial-resolution algorithms.RiassuntoObiettivoValutare l’influenza di spessore di strato, algoritmo di ricostruzione e corrente del tubo (mA) sulla performance di un software nella volumetria dei noduli polmonari solidi in TC multidetettore (TCMD).Materiali e metodiIl torace di un fantoccio, contenente noduli solidi artificiali di volume noto, è stato sottoposto a due scansioni TCMD, rispettivamente a 100 e 40 mAs (200 mA e 80 mA, tempo di rotazione di 0,5 s). I dati sono stati ricostruiti con spessori di strato di 1,25 e 2,5 mm e cinque differenti algoritmi. È stato calcolato il volume di tre noduli (iuxtavascolare, centroparenchimale, iuxtapleurico) con software tridimensionale (3D) e riportate le differenze tra volume stimato e reale, per ciascun nodulo e ricostruzione.RisultatiIl software ha segmentato tutti i noduli nelle ricostruzioni a spessore di strato di 1,25 mm, indipendentemente dai mAs. Non ha segmentato il nodulo iuxtapleurico a 2,5 mm e a 40 mAs. I kernel ad alta risoluzione spaziale hanno fornito valori medi di differenze dei volumi più prossimi al volume reale dei noduli nelle ricostruzioni a 1,25 mm, sia a 100 che a 40 mAs.ConclusioniSpessore di strato, algoritmo di ricostruzione e corrente del tubo possono influenzare la volumetria 3D dei noduli solidi. Lo spessore di 1,25 mm e gli algoritmi ad alta risoluzione hanno consentito la migliore performance del software, sia a 100 che a 40 mAs.

Comparison between whole-body MRI and Fluorine-18-Fluorodeoxyglucose PET or PET/CT in oncology: a systematic review

Abstract Background. The aim of the article is to systematically review published data about the comparison between positron emission tomography (PET) or PET/computed tomography (PET/CT) using Fluorine-18-Fluorodeoxyglucose (FDG) and whole-body magnetic resonance imaging (WB-MRI) in patients with different tumours. Methods. A comprehensive literature search of studies published in PubMed/MEDLINE, Scopus and Embase databases through April 2012 and regarding the comparison between FDG-PET or PET/CT and WB-MRI in patients with various tumours was carried out. Results. Forty-four articles comprising 2287 patients were retrieved in full-text version, included and discussed in this systematic review. Several articles evaluated mixed tumours with both diagnostic methods. Concerning the specific tumour types, more evidence exists for lymphomas, bone tumours, head and neck tumours and lung tumours, whereas there is less evidence for other tumour types. Conclusions. Overall, based on the literature findings, WB-MRI seems to be a valid alternative method compared to PET/CT in oncology. Further larger prospective studies and in particular cost-effectiveness analysis comparing these two whole-body imaging techniques are needed to better assess the role of WB-MRI compared to FDG-PET or PET/ CT in specific tumour types.

Usefulness of 18F-FDG PET/CT in Disease Extent and Treatment Response Assessment in a Patient With Syphilitic Aortitis

A 40-year-old man was admitted to our hospital for surgical treatment of aortic insufficiency and coronary ostial stenosis. Histopathology and serological tests revealed a syphilitic aortitis. F-FDG PET/CT was performed to assess the extent of aortitis, showing increased radiopharmaceutical uptake along the ascending aortic wall. A repeated FDG PET/CT after antibiotic therapy showed a markedly reduced uptake in the aortic wall, suggesting resolution of the infection according to clinical and serological data. This case highlights the usefulness of FDG PET/CT for the assessment of disease extent and treatment response in patients with syphilitic aortitis.

Integrated imaging of non-small cell lung cancer recurrence: CT and PET-CT findings, possible pitfalls and risk of recurrence criteria.

ObjectivesTo review the role of imaging in the diagnosis of recurrent disease in previously treated non-small cell lung cancer (NSCLC) and discuss the imaging pitfalls.MethodsA comprehensive review of published literature on CT and PET imaging of NSCLC recurrence was performed. Diagnostic and prognostic values are discussed. Representative imaging examples are illustrated.ResultsUp to 30% of NSCLC recurrences present as loco-regional, involving treated hemithorax and ipsilateral lymph nodes, while 70% present as metachronous distant metastases. CT and PET-CT play an important role in the early detection of recurrence; indications for imaging vary depending on pathological features.ConclusionImaging plays a central role in the identification of recurrence and may predict prognosis.Key PointsLung cancer recurs after surgery in 30% to 75% of patients.CT and PET-CT are crucial in identification of loco-regional recurrence.Knowledge of potential pitfalls is essential, especially for parenchymal or nodal recurrence.CT can diagnose metastases but further examinations (PET-CT, MRI) are often needed.Morphological and functional imaging criteria may help in predicting recurrence.

Necrotizing pneumonia and sepsis due to Clostridium perfringens: a case report

Clostridia are uncommon causes of pleuropulmonary infection. Clostridial species infecting the pleuropulmonary structures characteristically cause a necrotizing pneumonia with involvement of the pleura. Most cases have iatrogenic causes usually due to invasive procedures into the pleural cavity, such as thoracentesis or thoracotomy, or penetrating chest injuries. Rarely clostridia pleuropulmonary infections are not related to these factors. The clinical course of pleuropulmonary clostridial infections can be very variable, but they may be rapid and fatal. We report a rare case of necrotizing pneumonia and sepsis due to Clostridium perfringens not related to iatrogenic causes or injuries in an 82 years old woman.

Usefulness of fluorine-18 fluorodeoxyglucose Pet/computed tomography in diagnosis of aortitis and treatment response evaluation in a patient with aortic prosthesis

We report the case of an 82-year-old man with aortic prosthesis inflammation in whom fluorine-18 fluorodeoxyglucose (FDG) positron emission tomography/computed tomography has been useful in the detection of the cause of fever of unknown origin. We also describe the correlation between decrease of FDG uptake in the vascular prosthesis after treatment and clinical improvement with normalization of the serological levels of inflammatory markers.

Food residue granuloma mimicking metastatic disease on FDG-PET/CT

A 31-year-old woman presenting with acute abdomen underwent an emergency Hartmann’s procedure for fecal peritonitis due to perforated adenocarcinoma of the left colon. Shortly after a 7-month course of adjuvant chemotherapy, follow-up contrast-enhanced CT showed multiple peritoneal and hepatic nodules, showing focal intense and homogeneous FDG uptake on FDG-PET/CT, highly suspected for recurrence of disease. Excisional biopsy of the nodules revealed foreign body granulomas made up of alimentary materials surrounded by a fibrous wall. We report a unique case of a false-positive finding secondary to food residues mimicking metastatic disease on FDG-PET in a patient with colon cancer.