L. Bonello

CT perfusion in oncology: how to do it

Abstract Robust technique and accurate data analysis are required for reliable computed tomography perfusion (CTp) imaging. Multislice CT is required for high temporal resolution scanning; 16-slice (or 64-slice) scanners are preferred for adequate volume coverage. After tumour localization, the volume of CTp imaging has to be positioned to include the maximum visible area of the tumour and an adequate arterial vessel. Dynamic scans at high temporal resolution (at least 1-s gantry rotation time) are performed to visualize the first pass of contrast agent within the tumour; repeated scans with low temporal resolution can be planned for late enhancement assessment. A short bolus of conventional iodinated contrast agent, preferably with high iodine concentration, is power injected at a high flow rate (>4 ml/s) in the antecubital vein. The breath-hold technique is required for CTp imaging of the chest and upper abdomen to avoid respiratory motion; free breathing is adequate for CTp imaging of the head, neck and pelvis. Using dedicated software, a region of interest (ROI) has to be placed in an adequate artery (as arterial input) to obtain density–time curves; according to different kinetic models, colour maps of different CTp parameters are generated and generally overlaid on CT images. Additional ROIs can be positioned in the tumour, and in all other parts of the CTp volume, to obtain the values of the CTp parameters within the ROI.

Peritoneal carcinomatosis from ovarian cancer: the role of CT and [18F]FDG-PET/CT

PurposeThe diagnosis of peritoneal carcinomatosis secondary to ovarian cancer is a real challenge in the cancer imaging field. In this retrospective study, we evaluate the accuracy of Single Detector Computed Tomography (SDCT), Multi Detector Computed Tomography (MDCT), and Positron Emission Tomography–Computed Tomography with F18-fluorodeoxyglucose ([18F]FDG-PET/CT) in the diagnosis of peritoneal seeding and we evaluate the possible applications of MDCT to predict the complete surgical removal of the peritoneal deposits.Methods and materialsA total of 228 scans (91 SDCT, 89 MDCT, and 48 [18F]FDG-PET/CT) of patients with peritoneal carcinomatosis secondary to ovarian cancer proved at laparoscopy and confirmed by histopathology were retrospectively reviewed by two independent groups of Radiologists and Nuclear Medicine Physicians for the evaluation of ascites, peritoneal nodules, and omental cake signs.ResultsMDCT showed 81% of true positives, SDCT 72.5%, and [18F]FDG-PET/CT 77%. False negatives were 19% for MDCT, 27.5% for SDCT, and 23% for [18F]FDG-PET/CT.ConclusionFrom our results, we concluded that MDCT is the technique of choice in the diagnosis of peritoneal seeding, while [18F]FDG-PET/CT, though showing similar accuracy, remains the most accurate technique for monitoring therapeutic response and disease recurrence. MDCT could play an important role due to its ability to predict the possibility of complete surgical removal of disease thus influencing the treatment plan aimed to improve quality of life.

Perfusion CT in solid body-tumours part II. Clinical applications and future development

Perfusion computed tomography (CTP) has shown great potential in diagnosing tumours and evaluating and predicting treatment response and has been the subject of numerous experimental and clinical studies. Its increasing availability and simplicity allow it to be performed alongside morphological imaging to complete the evaluation of neoplastic lesions. The aim of this paper is to describe our personal experience and review the literature on the applications of CTP in tumours of different body regions, with particular regard to fields of development for new research. Increased clinical application is desirable, especially in relation to a wider use of antiangiogenic drugs. Additional and ideally multicentre studies are necessary to define the role of this technique.RiassuntoLa tomografia computerizzata perfusionale (TCp) ha dimostrato potenzialità nella diagnosi dei tumori, nella valutazione della risposta alla terapia e nella previsione di risposta ed è oggetto di numerosi studi sperimentali e clinici. La sua sempre più ampia disponibilità sul territorio e la semplicità di esecuzione la rendono una tecnica che affianca l’immagine morfologica e rende più completa la valutazione delle lesioni neoplastiche. Scopo di questo lavoro è descrivere i risultati personali e i dati descritti in letteratura sulle applicazioni della TCp nei tumori dei diversi distretti, con un particolare accento ai possibili campi di sviluppo per nuove ricerche in questo ambito. À auspicabile una sua applicazione clinica più estesa, soprattutto in relazione all’utilizzo sempre maggiore di farmaci antiangiogenetici. Ulteriori studi, possibilmente multicentrici, sono necessari per definire l’evidenza del ruolo di questa tecnica.

CT perfusion in solid-body tumours. Part I: technical issues

Functional imaging is becoming increasingly important in both research and clinical diagnostic radiology. Perfusion computed tomography (CTP) is a readily available and widely used tool that allows an objective measurement of tissue perfusion through the mathematical analysis of data obtained from repeated scans performed after administration of contrast agent. Recently, CTP has been increasingly used in the oncological field, being studied as a potential marker of neoplastic angiogenesis, which is one of the main targets of new tumour therapies. The aim of this paper was to provide the theoretical background and practical guidance for accurately performing CTP and interpreting results of examinations in solid-body tumours. CTP could be a valid tool for functional imaging of tumours if the acquisition technique is robust, if image and data analysis is accurate and if interpretation of results is adequately inserted within a clinical context.RiassuntoL’imaging funzionale sta acquisendo un ruolo sempre più importante, sia nella ricerca che nell’attività clinica della diagnostica per immagini. La tomografia computerizzata perfusionale (TCp) è una tecnica ampiamente disponibile e diffusa sul territorio, che permette di misurare oggettivamente la perfusione di un tessuto, attraverso l’analisi matematica dei dati ottenuti da scansioni ripetute nel tempo dopo la somministrazione di mezzo di contrasto. La TCp ha recentemente visto ampliare il suo impiego in ambito oncologico, perché viene studiata come possibile marcatore della angiogenesi neoplastica, che è uno dei principali target delle nuove terapie dei tumori. Scopo di questo lavoro è descrivere i presupposti teorici e fornire indicazioni pratiche per eseguire correttamente ed interpretare i risultati di esami di TCp sui tumori solidi del corpo. La TCp potrebbe essere uno valido strumento per l’imaging funzionale dei tumori, se la tecnica di acquisizione è robusta, se l’analisi di immagini e dati è accurata e se l’interpretazione dei risultati è adeguatamente inserita nel contesto clinico.

Computed Tomography-Guided Preoperative Radiotracer Localization of Nonpalpable Lung Nodules

BACKGROUND We describe preoperative computed tomography (CT)-guided injection of radiotracer technetium (99m) macroaggregates ((99m)Tc-MAA) in challenging small lung nodules, intraoperative localization, and resection. METHODS Between November 2007 and February 2010, 44 patients with 47 lung nodules which were detected incidentally or at screening and that were (18)F-fluorodeoxyglucose positron emission tomography ((18)F FDG-PET) positive or increasing in size at subsequent CT scans were candidates for surgical biopsy. Inclusion criteria for preoperative percutaneous CT-guided (low-dose technique) (99m)Tc-MAA localization included having at least one of the following characteristics: nodule size less than 1 cm, subsolid morphology, or distance from the pleura greater than 1 cm. RESULTS Mean nodule size was 11 mm (range, 5 to 24 mm); 24 nodules were nonsolid, 15 nodules were partially solid, and 8 nodules had a solid morphology. Mean distance from the pleura was 11 mm (range, 0 to 35 mm). Localization complications included 13 minor asymptomatic pneumothoraces, 9 parenchymal hemorrhage suffusions, 1 mild allergic reaction to contrast medium, and 2 patients with chest pain after the procedure. Nine patients had mild extravasation of radiotracer into the pleura. In 2 cases, there was an extravasation of a significant quantity of radiotracer into the pleural cavity. Thoracoscopic biopsy was performed in 30 cases, 2 cases were converted to thoracotomy, and 12 patients underwent intentional thoracotomy. CONCLUSIONS Asymptomatic subjects with suspicious nodules detected by screening or incidental CT are best candidates due to small lesion size and high percentage of nonsolid morphology, making thoracoscopic biopsy potentially difficult. Radiotracer localization is a safe, versatile, simple technique to help perform diagnosis with a minimally invasive approach in nonpalpable lung lesions.

Perfusion computed tomography in patients with hepatocellular carcinoma treated with thalidomide: initial experience.

Objective: The objective of the study was to evaluate the role of perfusion computed tomography (CT) for monitoring and predicting therapy response in patients with hepatocellular carcinoma treated with thalidomide. Methods: Twenty-four patients with advanced hepatocellular carcinoma were treated with thalidomide. Perfusion and conventional CT were performed at baseline and every 2 months until disease progression. Baseline tumor size and enhancement characteristics, as well as baseline perfusion parameters and their changes after therapy, were explored and tested for association with therapy response. Results: Perfusion CT was feasible in 18 patients. Baseline tumor size and enhancement characteristics showed no predictive value, whereas baseline blood flow and blood volume were higher in patients with progressive disease (P < 0.042), with cutoff values for blood flow (16.7 mL/100 g per minute) and blood volume (1.84 mL/100 g) predicting progressive disease in 83.3% and 77.8% of patients, respectively. Significant changes were observed after 2, 4, and 6 months in blood flow (P < 0.031), blood volume after 4 months (P = 0.018), and mean transit time after 4 and 6 months (P = 0.030) in patients with stable disease at 6 months. Conclusions: Baseline blood flow and blood volume predicted response to therapy in our cohort.

Breast MR with special focus on DW-MRI and DCE-MRI

Abstract The use of magnetic resonance imaging (MRI) for the assessment of breast lesions was first described in the 1970s; however, its wide application in clinical routine is relatively recent. The basic principles for diagnosis of a breast lesion rely on the evaluation of signal intensity in T2-weighted sequences, on morphologic assessment and on the evaluation of contrast enhancement behaviour. The quantification of dynamic contrast behaviour by dynamic contrast-enhanced (DCE) MRI and evaluation of the diffusivity of water molecules by means of diffusion-weighted MRI (DW-MRI) have shown promise in the work-up of breast lesions. Therefore, breast MRI has gained a role for all indications that could benefit from its high sensitivity, such as detection of multifocal lesions, detection of contralateral carcinoma and in patients with familial disposition. Breast MRI has been shown to have a role in monitoring of neoadjuvant chemotherapy, for the evaluation of therapeutic results during the course of therapy. Breast MRI can improve the determination of the remaining tumour size at the end of therapy in patients with a minor response. DCE-MRI and DW-MRI have shown potential for improving the early assessment of tumour response to therapy and the assessment of residual tumour after the end of therapy. Breast MRI is important in the postoperative work-up of breast cancers. High sensitivity and specificity have been reported for the diagnosis of recurrence; however, pitfalls such as liponecrosis and changes after radiation therapy have to be carefully considered.

Role of operator experience in ultrasound-guided fine-needle aspiration biopsy of the thyroid

PurposeThyroid nodules are commonly encountered in clinical practice, and ultrasound (US)-guided fine-needle aspiration biopsy (FNAB) is the gold standard in diagnosing the pathological nature of undetermined thyroid nodules. The aim of this study was to evaluate whether operator experience influences the diagnostic accuracy of US-guided FNAB.Materials and methodsA total of 700 consecutive US-guided FNAB done by a single radiologist between 2000 and 2007 were retrospectively analysed. The same freehand technique and capillary-action technique with 22- or 25-gauge needles was used for all nodules, All specimens were prepared and fixed without the cytologist on site and were subsequently analysed by two expert cytologists. The procedures were chronologically divided into seven groups and classified as diagnostic or nondiagnostic.ResultsThe rate of nondiagnostic procedures for each group was 32% in group 1, 13% in group 2, 17% in group 3, 11% in group 4, 10% in group 5, 5% in group 6 and 8% in group 7. No major complications were recorded.ConclusionsThe rate of nondiagnostic US-guided FNAB is heavily dependent on the operator’s experience. We estimated that at least 200 procedures need to be performed in order to achieve the levels of diagnostic accuracy reported in the literature. We therefore suggest specific training before operators routinely perform this procedure in clinical practice.RiassuntoObiettivoI noduli tiroidei costituiscono un riscontro comune nella pratica clinica e la biopsia con ago sottile (FNAB)-ecoguidata rappresenta il gold standard diagnostico nella valutazione di pazienti con noduli indeterminati. L’obiettivo di questo studio è valutare quanto l’esperienza dell’operatore influisca sull’accuratezza diagnostica degli agoaspirati tiroidei ecoguidati.Materiali e metodiSono state valutate retrospettivamente 700 FNAB-ecoguidate consecutive eseguite da un singolo radiologo dal 2000 al 2007, effettuate con tecnica a mano libera per capillarità con aghi da 22 G o 25 G, preparati ed allestiti senza citologo. Tutti i prelievi sono stati analizzati successivamente da due citologi esperti. Le procedure sono state stratificate cronologicamente in 7 gruppi e classificate come diagnostiche o non diagnostiche.RisultatiLe procedure non diagnostiche di ogni singolo Gruppo sono: 32% nel Gruppo 1, 13% nel Gruppo 2, 17% nel Gruppo 3, 11% nel Gruppo 4, 10% nel Gruppo 5, 5% nel Gruppo 6 e 8% nel Gruppo 7. Non sono state riportate complicanze maggiori.ConclusioniLa percentuale non-diagnostica di FNAB-ecoguidate tiroidee è fortemente dipendente dall’esperienza dell’operatore. Abbiamo stimato che siano necessarie almeno 200 procedure prima di raggiungere valori di accuratezza diagnostica riportati in letteratura. Suggeriamo pertanto uno specifico training dell’operatore prima di intraprendere questa procedura nella pratica clinica.

Intraobserver and interobserver variability in the calculation of apparent diffusion coefficient (ADC) from diffusion-weighted magnetic resonance imaging (DW-MRI) of breast tumours

PurposeThis study evaluated intraobserver and interobserver variability in the measurement of apparent diffusion coefficient (ADC) values in breast carcinomas.Materials and methodsTwenty-eight patients with solid breast lesions >10 mm underwent conventional contrast-enhanced magnetic resonance imaging (MRI) and diffusion-weighted MRI (DW-MRI). Two observers (expert and trainee) segmented the lesion from the surrounding breast tissue on DW images with high b-value (1,000 s/mm2). This analysis was repeated by the expert reader after 6 months. Volumes were analysed to obtain mean, median and standard deviation (SD) of the ADC values. Interobserver and intraobserver variation was analysed using the Bland-Altman graph.ResultsAll lesions were breast carcinomas, with a mean ADC value of 1.07 × 10−3 mm2/s. The mean of the differences was 0.012 × 10−3 mm2/s, corresponding to an intraobserver variability of 1.1% (limits of agreement: −5%/+8%). The mean interobserver difference was 0.022 × 10−3 mm2/s, corresponding to an interobserver variability of 2% (limits of agreement: −9%/+14%).ConclusionsWe found a low intraobserver and interobserver variability in calculating ADC in breast carcinomas, which supports its potential use in routine clinical practice.RiassuntoObiettivoObiettivo del nostro lavoro è stato determinare la variabilità intra-osservatore e inter-osservatore nel calcolo del coefficiente di diffusione apparente (ADC) nei carcinomi mammari (CM).Materiali e metodiVentotto pazienti con lesioni mammarie solide >10 mm sono state sottoposte a risonanza magnetica (RM) convenzionale con mezzo di contrasto e a RM pesata in diffusione (RM-DW). Due osservatori hanno isolato la lesione dal tessuto mammario circostante nelle sequenze con elevata pesatura in diffusione (b-value=1000 s/mm2); tale analisi è stata ripetuta da un osservatore dopo 6 mesi. Per i volumi ottenuti sono state calcolate media, mediana e deviazione standard dell’ADC. La variabilità intra-osservatore e la variabilità inter-osservatore sono state valutate tramite il metodo di Bland e Altman.RisultatiTutte le lesioni sono risultate CM, con un valore medio di ADC di 1,07×10−3 mm2/s. è stata calcolata una media delle differenze di 0,012×10−3 mm2/s, corrispondente ad una variabilità intra-osservatore di 1,1% (limiti di accordo −5%/+8%). È stata calcolata una media delle differenze di 0,022×10−3 mm2/s, corrispondente ad una variabilità inter-osservatore di 2% (limiti di accordo di −9%/+14%).ConclusioniÈ stata osservata una bassa variabilità intraosservatore e inter-osservatore per il calcolo dell’ADC nei CM, la quale supporta un suo possibile utilizzo nella routine clinica.

The role of ultrasound-guided transcutaneous tru-cut biopsy in diagnosing untreated and recurrent laryngo-hypopharyngeal masses

OBJECTIVE To evaluate the diagnostic performance of Ultrasound-guided Transcutaneous Tru-Cut biopsy (USGTCB) of laryngo-hypopharyngeal masses suspicious for malignancy. Furthermore we investigated whether USGTCB is accurate for both untreated masses and suspected recurrences. MATERIALS AND METHODS From August 2004 to July 2014 we prospectively enrolled 66 patients for a total of 68 USGTCBs: 38 USGTCB were performed for a suspicious untreated mass and in 30 for a suspected recurrence. We calculated the sensitivity, specificity, positive predictive value and negative predictive value for all procedures and separately for untreated masses and suspected recurrences. RESULTS USGTCB diagnosed 57 malignancies (51 squamous cell carcinomas, 6 other tumors) and 11 benign lesions. There were no false positives reported, whereas five false negatives were observed: two in patients with an untreated mass, three in patients with a suspected recurrence. Overall, the sensitivity of the technique was 91.9% (95% confidence interval [CI]: 82.2-97.3%); the specificity was 100% (95% CI: 54.1-100%); positive and negative predictive values were 100% (95% CI: 93.7-100%) and 54.5% (95% CI: 23.5-83.1%) respectively, with similar performances in untreated masses and suspected recurrences of SCC. CONCLUSION USGTCB is an effective procedure for the histological diagnosis of laryngo-hypopharyngeal masses suspicious for malignancy in patients showing contraindications to biopsy via microlaryngoscopy under general, with similar performances for untreated masses and suspected recurrences.