Form Factors as Potential Imaging Biomarkers to Differentiate Benign vs. Malignant Lung Lesions on CT Scans.

Indeterminate lung nodules detected on CT scans are common findings in clinical practice. Their correct assessment is critical, as early diagnosis of malignancy is crucial to maximise the treatment outcome. In this work, we evaluated the role of form factors as imaging biomarkers to differentiate benign vs. malignant lung lesions on CT scans. We tested a total of three conventional imaging features, six form factors, and two shape features for significant differences between benign and malignant lung lesions on CT scans. The study population consisted of 192 lung nodules from two independent datasets, containing 109 (38 benign, 71 malignant) and 83 (42 benign, 41 malignant) lung lesions, respectively. The standard of reference was either histological evaluation or stability on radiological followup. The statistical significance was determined via the Mann-Whitney U nonparametric test, and the ability of the form factors to discriminate a benign vs. a malignant lesion was assessed through multivariate prediction models based on Support Vector Machines. The univariate analysis returned four form factors (Angelidakis compactness and flatness, Kong flatness, and maximum projection sphericity) that were significantly different between the benign and malignant group in both datasets. In particular, we found that the benign lesions were on average flatter than the malignant ones; conversely, the malignant ones were on average more compact (isotropic) than the benign ones. The multivariate prediction models showed that adding form factors to conventional imaging features improved the prediction accuracy by up to 14.5 pp. We conclude that form factors evaluated on lung nodules on CT scans can improve the differential diagnosis between benign and malignant lesions.

Agenesis of Infrarenal Abdominal Aorta and Iliac Arteries.

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Dynamic contrast-enhanced and diffusion-weighted MR imaging in the characterisation of small, non-palpable solid testicular tumours.

OBJECTIVES: To explore the role of dynamic contrast-enhanced (DCE) magnetic resonance imaging (MRI), using semiquantitative and quantitative parameters, and diffusion-weighted (DW) MRI in differentiating benign from malignant small, non-palpable solid testicular tumours. METHODS: We calculated the following DCE-MRI parameters of 47 small, non-palpable solid testicular tumours: peak enhancement (PE), time to peak (TTP), percentage of peak enhancement (Epeak), wash-in-rate (WIR), signal enhancement ratio (SER), volume transfer constant (Ktrans), rate constant (Kep), extravascular extracellular space volume fraction (Ve) and initial area under the curve (iAUC). DWI signal intensity and apparent diffusion coefficient (ADC) values were evaluated. RESULTS: Epeak, WIR, Ktrans , Kep and iAUC were higher and TTP shorter in benign compared to malignant lesions (p < 0.05). All tumours had similar ADC values (p > 0.07). Subgroup analysis limited to the most frequent histologies - Leydig cell tumours (LCTs) and seminomas - replicated the findings of the entire set. Best diagnostic cutoff value for identification of seminomas: Ktrans ≤0.135 min-1, Kep ≤0.45 min-1, iAUC ≤10.96, WIR ≤1.11, Epeak ≤96.72, TTP >99 s. CONCLUSIONS: DCE-MRI parameters are valuable in differentiating between benign and malignant small, non-palpable testicular tumours, especially when characterising LCTs and seminomas. KEY POINTS: • DCE-MRI may be used to differentiate benign from malignant non-palpable testicular tumours. • Seminomas show lower Ktrans, Kep and iAUC values. • ADC values are not valuable in differentiating seminomas from LCTs. • Semiquantitative DCE-MRI may be used to characterise small, solid testicular tumours.

Simplified Prostate Imaging Reporting and Data System for Biparametric Prostate MRI: A Proposal.

OBJECTIVE: We describe our institutional experience using a simplified Prostate Imaging Reporting and Data System (PI-RADS) based on biparametric prostate MRI. We discuss two important controversies: the use of gadolinium-based contrast agents and the management of PI-RADS category 3 lesions. CONCLUSION: Our simplified PI-RADS identifies four categories and suggests management strategies for each. The simplified PI-RADS can be an effective system to facilitate multidisciplinary cooperation and to improve the management of suspected prostate cancer.

A Case of Fatal Cerebral Air Embolism After Blunt Lung Trauma: Postmortem Computed Tomography and Autopsy Findings.

Cerebral air embolism is caused by gas bubbles in the vascular system. These bubbles can cause cerebral ischemia by obstructing encephalic blood vessels. It is frequently associated with blunt and penetrating chest trauma as well as iatrogenic interventions. Lung trauma involving laceration of the respiratory tract, lung parenchyma, and blood vessels may result in direct communication of these structures, driving air or gas into the pulmonary venous system. We report a case of a blunt chest trauma that led to massive arterial air embolism that was possible to recognize with the help of postmortem computed tomographic scan examination.

Comparison between locked and unlocked intramedullary nails in intertrochanteric fractures.

BACKGROUND: Intertrochanteric fractures are of great interest worldwide and are the most frequently operated fractures. Intramedullary nailing is commonly used in the treatment of intertrochanteric fractures. The purpose of this study is to assess the necessity of using the distal blocking screw in 31-A1 and 31-A2 fractures, classified according to the Orthopaedic Trauma Association classification system (AO/OTA). METHODS: This is a prospective study of 143 consecutive patients (mean age 85.01 years, mean final follow-up 14.1 months) surgically treated with the same intramedullary nail. In 75 cases, the distal locking screw was not used. Parameters evaluated during follow-up were: blood loss, transfusion requirements, surgery duration, and fluoroscopy time. Harris Hip Score and Barthel Activity Daily Living were used for the clinical evaluation. Radiographic Union Score For Hip (RUSH score) and Tip apex distance (TAD) were measured for radiologic evaluation. RESULTS: The group treated without locking screw showed significantly shorter surgical duration time (31.9 vs. 47.2 min), a decrease in blood loss (variation Hb - 1.06 vs. - 1.97), and reduced X-rays exposure time (25.4 vs. 31.6 s). No significant differences were observed in the postoperative period and in the radiographic and clinical scores. CONCLUSION: This study demonstrates that in intertrochanteric 31-A1 and 31-A2 stable fractures, the absence of distal locking screw does not compromise bone healing and prevents several clinical complications.

Lesion volume predicts prostate cancer risk and aggressiveness: validation of its value alone and matched with prostate imaging reporting and data system score.

OBJECTIVE: To demonstrate the association between magnetic resonance imaging (MRI) estimated lesion volume (LV), prostate cancer detection and tumour clinical significance, evaluating this variable alone and matched with Prostate Imaging Reporting and Data System version 2 (PI-RADS v2) score. PATIENTS AND METHODS: We retrospectively analysed 157 consecutive patients, with at least one prior negative systematic prostatic biopsy, who underwent transperineal prostate MRI/ultrasonography fusion-targeted biopsy between January 2014 and February 2016. Suspicious lesions were delineated using a 'region of interest' and the system calculated prostate volume and LV. Patients were divided in groups considering LV (≤0.5, 0.5-1, ≥1 mL) and PI-RADS score (1-5). We considered clinically significant prostate cancer as all cancers with a Gleason score of ≥3 + 4 as suggested by PI-RADS v2. A direct comparison between MRI estimated LV (MRI LV) and histological tumour volume (HTV) was done in 23 patients who underwent radical prostatectomy during the study period. Differences between MRI LV and HTV were assessed using the paired sample t-test. MRI LV and HTV concordance was verified using a Bland-Altman plot. The chi-squared test and logistic and ordinal regression models were used to evaluate difference in frequencies. RESULTS: The MRI LV and PI-RADS score were associated both with prostate cancer detection (both P < 0.001) and with significant prostate cancer detection (P < 0.001 and P = 0.008, respectively). When the two variables were matched, increasing LV increased the risk within each PI-RADS group. Prostate cancer detection was 1.4-times higher for LVs of 0.5-1 mL and 1.8-times higher for LVs of ≥1 mL; significant prostate cancer detection was 2.6-times for LVs of 0.5-1 mL and 4-times for LVs of ≥1 mL. There was a positive correlation between MRI LV and HTV (r = 0.9876, P < 0.001). Finally, Bland-Altman analysis showed that MRI LV was underestimated by 4.2% compared to HTV. Study limitations include its monocentric and retrospective design and the limited cohort. CONCLUSIONS: This study demonstrates that PI-RADS score and the MRI LV, independently and in combination, are associated with prostate cancer detection and with tumour clinical significance.

Bi-parametric magnetic resonance imaging applied to obstetrics.

Foetal magnetic resonance imaging (MRI) plays an increasingly important role in the diagnosis of foetal abnormalities. Over the years, we have successfully applied bi-parametric MRI (bp-MRI) to the following obstetric conditions: (1) neurologic vascular diseases; (2) assessment of lung parenchyma maturation; (3) renal pathologies, such as polycystic kidney, suspected renal infarction, unilateral or bilateral renal agenesis; (4) placental pathologies, as twin-twin transfusion syndrome or placenta accreta; (5) benignant and malignant congenital tumours or cysts of the liver, such as haemangioendothelioma, hepatoblastoma or metastatic neuroblastoma, of the kidney (e.g. mesoblastic nephroma) and of the retroperitoneum, such as teratoma. The information derived from bp-MRI, and concerned with water motions in different tissues, improved the morphologic details provided by conventional foetal MRI. It has the potential to increase the value of MRI in the assessment of a wide range of foetal pathologies, particularly in renal diseases, allowing an adequate management decision and therapy.

FDG PET and Split-Bolus Multi-Detector Row CT Fusion Imaging in Oncologic Patients: Preliminary Results.

PURPOSE: To assess the incremental value of split-bolus multidetector computed tomography (CT) combined with fluorine 18 fluorodeoxyglucose (FDG) positron emission tomography (PET) for follow-up of oncologic patients. MATERIALS AND METHODS: The institutional ethics committee approved the use of this protocol. Thirty-eight oncologic patients who underwent FDG PET/unenhanced multidetector CT and split-bolus multidetector CT for restaging were investigated retrospectively. The split-bolus CT protocol included imaging during the hepatic arterial and portal venous phases in one scan. Software was used for fusion of the independently acquired FDG PET and split-bolus CT data, and fused datasets were compared with FDG PET/unenhanced CT data. The standard of reference for diagnosis of lesions in all patients was a combination of histologic results (if available), clinical results (medical history, physical examination, and laboratory test results), and the results of follow-up imaging (conventional CT, magnetic resonance imaging, and/or ultrasonography) for at least 6 months. Descriptive statistics were used. RESULTS: Fifty-nine true-positive lesions were identified with fused FDG PET/split-bolus CT; 41 were concordant and detected with both split-bolus CT and PET/unenhanced CT, 16 with split-bolus CT only, and two with PET/unenhanced CT. Two different false-positive lesions were identified with PET/unenhanced CT and PET/split-bolus CT. Furthermore, in 20 of 38 (53%) patients, FDG PET/split-bolus CT allowed detection of important additional findings (n = 40) not detected at FDG PET/unenhanced CT. Both the tumor-related findings (n = 13, 32.5%) and the non-tumor-related findings (n = 27, 67.5%) were important to the clinical treatment of these patients. CONCLUSION: Fused FDG PET/split-bolus multidetector CT provides additional information compared with FDG PET/unenhanced multidetector CT in oncologic patients.

Endovascular management of massive post-partum haemorrhage in abnormal placental implantation deliveries.

OBJECTIVES: To retrospectively evaluate safety and efficacy of pelvic artery embolisation (PAE) in post-partum haemorrhage (PPH) in abnormal placental implantation (API) deliveries. METHODS: From January 2009 to November 2013, 12 patients with API and intractable intraoperative PPH underwent PAE after caesarean delivery to control a haemorrhage (in four of these cases after hysterectomy). Arterial access was obtained prior to the delivery; PAE was performed in the obstetrics operating room by an interventional radiologist that was present with an interventional radiology (IR) team during the delivery. RESULTS: PAE was successful in preventing bleeding and avoid hysterectomy in four cases (group A). Uterine atony and disseminated intravascular coagulation caused failure of PAE requiring hysterectomy in four patients (group B). PAE prevented bleeding post-hysterectomy in the remaining four cases (group C). Technical success (cessation of contrast extravasation on angiography or occlusion of the selected artery) was 100 %. Maternal and foetal mortality and morbidity were 0 %. CONCLUSIONS: PAE is a minimal invasive technique that may help to prevent hysterectomy and control PPH in API pregnancies without complications. Embolisation should be performed on an emergency basis. For such cases, an IR team on standby in the obstetrics theatre may be useful to prevent hysterectomy, blood loss and limit morbidity. KEY POINTS: • Endovascular treatment is a validated technique in post-partum haemorrhage. • Abnormal placental implantation is a risk factor for post-partum haemorrhage. • We propose an interventional radiologist standby in the delivery room.

Influence of hormonal therapy in prostate cancer patients undergoing [18F]fluoromethyl choline PET/CT: a retrospective study.

BACKGROUND: Patients with suspected recurrence of prostate cancer undergoing [18F]fluoromethyl choline ([18F]FCH) PET/CT were retrospectively evaluated to investigate the influence of hormonal therapy (HT) in [18F]FCH uptake. METHODS: [18F]FCH PET/CT was performed in 102 surgically treated patients with suspected recurrence (PSA increase >0.2 ng/mL) of prostate cancer, divided in two groups: under HT (N.=54) and without HT (N.=48) at the time of PET scanning. PET/CT was carried out by an integrated system (Biograph 6, CTI/Siemens, Knoxville, TN, USA) intravenously by administering 4.1 MBq/kg of [18F]FCH to each patient; images were acquired 60 minutes later. RESULTS: On the total number of patients, 66 were found to be true positives (TP), 9 false positives (FP), 5 false negatives (FN) and 22 true negatives (TN), sensitivity to [18F]FCH PET/CT was 93%, specificity 71%, accuracy 86%, positive predictive value (PPV) 88%, negative predictive value (NPV) 81%. In the 54 patients under HT, 38 were TP, 6 FP, 3 FN and 7 TN, sensitivity was 93%, specificity 54%, accuracy 83%, PPV 86% and NPV was 70%. In the 48 patients receiving no HT, 28 were TP, 3 FP, 2 FN and 15 TN, sensitivity was 93%, specificity 83%, accuracy 90%, PPV 90% and NPV 88%. A χ2 test showed that sensitivity, accuracy and PPV did not differ among patients with and without HT, while specificity and NPV were significantly lower (P<0.001) in HT treated patients. CONCLUSIONS: Sensitivity, accuracy and PPV were similar in patients with and without HT. Specificity and NPV were reduced in patients under HT, but further data are necessary to support if this reduction is casual or related to therapy and it could be confirmed in a larger series of patients.

A prospective study on contrast-enhanced magnetic resonance imaging of testicular lesions: distinctive features of Leydig cell tumours.

OBJECTIVES: Up to 20 % of incidentally found testicular lesions are benign Leydig cell tumours (LCTs). This study evaluates the role of contrast-enhanced magnetic resonance imaging (MRI) in the identification of LCTs in a large prospective cohort study. MATERIALS AND METHODS: We enrolled 44 consecutive patients with at least one solid non-palpable testicular lesion who underwent scrotal MRI. Margins of the lesions, signal intensity and pattern of wash-in and wash-out were analysed by two radiologists. The frequency distribution of malignant and benign MRI features in the different groups was compared by using the chi-squared or Fisher's exact test. Sensitivity, specificity, positive and negative predictive value, and diagnostic accuracy were calculated. RESULTS: The sensitivity of scrotal MRI to diagnose LCTs was 89.47 % with 95.65 % specificity; sensitivity for malignant lesions was 95.65 % with 80.95 % specificity. A markedly hypointense signal on T2-WI, rapid and marked wash-in followed by a prolonged washout were distinctive features significantly associated with LCTs. Malignant lesions were significantly associated with blurred margins, weak hypointense signal on T2-WI ,and weak and progressive wash-in. The overall diagnostic accuracy was 93 %. CONCLUSIONS: LCTs have distinctive contrast-enhanced MRI features that allow the differential diagnosis of incidental testicular lesions. KEY POINTS: • MRI is able to characterize testicular lesions suggesting a specific diagnosis. • Rapid and marked wash-in is a common feature of Leydig cell tumours. • Markedly hypointense T2-WI signal is significantly correlated with benign lesions. • Blurred margins and weak hypointense T2-WI signal are correlated with malignant tumours. • Weak and progressive wash-in features are present in 85 % of seminomatous lesions.