Response Assessment by Volumetric Iodine Uptake Measurement: Preliminary Experience in Patients with Intermediate-Advanced Hepatocellular Carcinoma Treated with Yttrium-90 Radioembolization.

PURPOSE: To retrospectively compare early response to yttrium-90 radioembolization (Y90) according to volumetric iodine uptake (VIU) changes, Response Evaluation Criteria In Solid Tumor 1.1 (RECIST 1.1) and modified RECIST (mRECIST) in patients with intermediate-advanced hepatocellular carcinoma (HCC) and to explore their association with survival. MATERIALS AND METHODS: Twenty-four patients treated with Y90 and evaluated with dual-energy computed tomography before and 6 weeks after treatment were included. VIU was measured on late arterial phase spectral images; 6-week VIU response was defined as: complete response (CR, absence of enhancing tumor), partial response (PR, ≥ 15% VIU reduction), progressive disease (PD, ≥ 10% VIU increase) and stable disease (criteria of CR/PR/PD not met). RECIST 1.1 and mRECIST were evaluated at 6 weeks and 6 months. Responders included CR and PR. Overall survival (OS) was evaluated by Kaplan-Meier analysis and compared by Cox regression analysis. RESULTS: High intraobserver and interobserver agreements were observed in VIU measurements (k > 0.98). VIU identified a higher number of responders (18 patients, 75%), compared to RECIST 1.1 (12.5% at 6 weeks and 23.8% at 6 months) and mRECIST (29.2% at 6 weeks and 61.9% at 6 months). There was no significant correlation between OS and RECIST 1.1 (P = 0.45 at 6 weeks; P = 0.21 at 6 months) or mRECIST (P = 0.38 at 6 weeks; P = 0.79 at 6 months); median OS was significantly higher in VIU responders (17.2 months) compared to non-responders (7.4 months) (P = 0.0022; HR 8.85; 95% CI 1.29-88.1). CONCLUSION: VIU is highly reproducible; as opposite to mRECIST and RECIST 1.1, early VIU response correlates with OS after Y90 in intermediate-advanced HCC patients.

Image fusion of preprocedural CTA with real-time fluoroscopy to guide proper hepatic artery catheterization during transarterial chemoembolization of hepatocellular carcinoma: a feasibility study.

PURPOSE: To assess feasibility of proper hepatic artery catheterization using a 3D model obtained from preprocedural computed tomographic angiography (CTA), fused with real-time fluoroscopy, during transarterial chemoembolization of hepatocellular carcinoma. METHODS: Twenty consecutive cirrhotic patients with hepatocellular carcinoma undergoing transarterial chemoembolization were prospectively enrolled onto the study. The early arterial phase axial images of the preprocedural CTA were postprocessed on an independent workstation connected to the angiographic system (Innova 4100; GE Healthcare, Milwaukee, WI), obtaining a 3D volume rendering image (VR) that included abdominal aorta, splanchnic arteries, and first and second lumbar vertebrae. The VR image was manually registered to the real-time X-ray fluoroscopy, with the lumbar spine used as the reference. The VR image was then used as guidance to selectively catheterize the proper hepatic artery. The procedure was considered successful when performed with no need for intraarterial contrast injections or angiographic acquisitions. RESULTS: The procedure was successful in 19 (95 %) of 20 patients. In one patient, celiac trunk angiography was required for the presence of a significant ostial stenosis that was underestimated at computed tomography. Time for image reconstruction and registration was <10 min in all cases. CONCLUSION: The use of preprocedural CTA model with fluoroscopy enables confident and direct catheterization of the proper hepatic artery with no need for preliminary celiac trunk angiography, thus reducing radiation exposure and contrast media administration.

Role of dynamic MRI in the follow-up of acute Charcot foot in patients with diabetes mellitus.

PURPOSE: To evaluate the usefulness of magnetic resonance imaging (MRI) in assessing the level of activity of acute Charcot foot, monitoring treatment response and predicting healing time. MATERIALS AND METHODS: Forty diabetic patients with acute Charcot foot were prospectively enrolled. Patients underwent limb immobilization and were followed every 3 months by clinical examination (skin temperature and circumferences) and MRI. MR protocol included T1-weighted and fast spin echo inversion recovery (FSE-IR) sequences, and a dynamic study (fast spoiled gradient echo), after gadolinium administration (0.1 ml/kg). The contrast medium uptake rate at D-MRI and the signal intensity (SI) ratio on the FSE-IR sequence were measured. RESULTS: At baseline, mean contrast medium uptake rate was 136 ± 49.7% and the mean SI ratio was 5 ± 3. A high intra- and inter-observer agreement was found for the contrast medium uptake rate, whereas a low agreement was observed for the SI ratio. At 3 months' follow-up, reduction of the contrast medium uptake rate was observed in all patients with improved clinical findings (n = 34), whereas the SI ratio was reduced in 15/34 (44.1%) patients. Mean healing time was significantly related to the baseline contrast medium uptake rate (P=0.005); it was 5.3 ± 2.7 months in patients with contrast medium uptake rate ≤ 100%, compared with 9.1 ± 2.5 months in the remaining patients (P=0.0003). CONCLUSIONS: Contrast medium uptake rate obtained at D-MRI represents a reproducible parameter that is reliable for predicting and monitoring treatment outcome in acute Charcot foot.

CT colonography: role of a second reader CAD paradigm in the initial training of radiologists.

PURPOSE: To evaluate the influence of CAD for the evaluation of CT colonography (CTC) datasets by inexperienced readers during the attendance of a dedicated hands-on training course. METHOD AND MATERIALS: Twenty-seven radiologists inexperienced in CTC (11 with no CTC training at all, 16 having previously reviewed no more than 10 CTC cases overall) attended a hands-on training course based on direct teaching on fifteen workstations (four Advantage Windows 4.4 with Colon VCAR software, GE; six CADCOLON, Im3D; five ColonScreen (Toshiba/Voxar) with ColonCAD™ API, Medicsight). During the course, readers were instructed to analyze 26 CTC cases including 38 colonic lesions obtained through low-dose MDCT acquisitions, consisting of 12 polyps sized less than 6 mm, 9 polyps sized between 6 and 10 mm, 12 polyps sized between 11 mm and 30 mm, and 5 colonic masses sized>3 cm. CTC images were reviewed by each reader both in 2D and 3D mode, respectively by direct evaluation of native axial images and MPR reconstructions, and virtual endoscopy or dissected views. Each reader had 15 min time for assessing each dataset without CAD, after which results were compared with those provided by CAD software. Global rater sensitivity for each lesion size before and after CAD usage was compared by means of two-tailed Student's t test, while sensitivity of each single reader before and after CAD usage was assessed with the McNemar test. RESULTS: For lesions sized<6 mm, global rater sensitivity was 0.1852±0.1656 (mean±SD) before CAD-assisted reading and 0.2345±0.1761 after CAD (p=0.0018). For lesions sized 6-9 mm, sensitivity was 0.2870±0.1016 before CAD-assisted reading and 0.3117±0.1099 after CAD (p=0.0027). For lesions sized 10-30 mm, sensitivity was 0.5308±0.2120 before CAD-assisted reading and 0.5637±0.2133 after CAD (p=0.0086), while for lesions sized>30 mm, sensitivity before CAD-assisted reading was 0.3556±0.3105 and did not change after CAD usage (p=1). Sensitivity of each single rater did not significantly differ before and after CAD for any lesion size category (McNemar test, p>0.05). Specificity was not significantly different before and after CAD for any lesion size (>96% for all size categories). CONCLUSION: CAD usage led to increased overall sensitivity of inexperienced readers for all polyps sizes, except for lesions>30 mm, but sensitivity of individual raters was not significantly higher compared with CAD-unassisted reading.

Integrating image processing in PACS.

Integration of RIS and PACS services into a single solution has become a widespread reality in daily radiological practice, allowing substantial acceleration of workflow with greater ease of work compared with older generation film-based radiological activity. In particular, the fast and spectacular recent evolution of digital radiology (with special reference to cross-sectional imaging modalities, such as CT and MRI) has been paralleled by the development of integrated RIS--PACS systems with advanced image processing tools (either two- and/or three-dimensional) that were an exclusive task of costly dedicated workstations until a few years ago. This new scenario is likely to further improve productivity in the radiology department with reduction of the time needed for image interpretation and reporting, as well as to cut costs for the purchase of dedicated standalone image processing workstations. In this paper, a general description of typical integrated RIS--PACS architecture with image processing capabilities will be provided, and the main available image processing tools will be illustrated.

Comparison of CT colonography vs. conventional colonoscopy in mapping the segmental location of colon cancer before surgery.

Once presence of a colorectal cancer has been diagnosed, a key factor for patient's prognosis in view of surgical intervention is the correct segmental localization and resection of the tumor. The aim of this work was to compare the accuracy of the current gold standard technique, conventional colonoscopy (CC), to computed tomography colonography (CTC) in the segmental localization of tumor. Sixty-five patients (mean age 64; 45 female and 19 male) with colorectal cancer diagnosed at colonoscopy underwent CTC before surgery. In 45 out of 65 cases (69%), patients were referred to CTC after incomplete CC. Reasons were patient intolerance to CC or presence of stenosing cancer, with consistent difficulties in crossing the tract of the colon involved by the lesion. CTC allowed the complete colonic examination in 63/65 cases, since in 2 patients with an obstructing lesion of the sigmoid colon, pneumocolon could not be obtained. However, per patient and per lesion sensitivity of CTC was 100%. Difference from colonoscopy was statistically significant (P < 0.05). In terms of segmental localization of masses, CTC located precisely all lesions, while colonoscopy failed in 16/67 (24%) lesions, though six were missed for incomplete colonoscopy (9%). In the remaining 10/67 (15%) lesions, detected by colonoscopy but incorrectly located, the mismatch occurred in the rectum (n = 3), sigmoid (n = 2), descending (n = 1), transverse (n = 2), ascending colon, and cecum. Agreement between CTC and CC was fair (k value 0.62). Sensitivity, specificity, positive predictive value and negative predictive value of CTC in determining the precise location of colonic masses were respectively 100%, 96%, 85%, and 100%. CT detected hepatic (6/65 patients) and lung metastases (3/65 patients). CT colonography has better performance in the identification of colonic masses (diameter > 3 cm), in the completion of colonic evaluation and in the segmental localization of tumor. CTC should replace colonoscopy for preoperative staging of colorectal cancer.

CT colonography versus double-contrast barium enema for screening of colorectal cancer: comparison of radiation burden.

Our aim is to compare the radiation dose associated with a low-dose CT colonography (CTC) protocol for colorectal cancer screening with that delivered by double-contrast barium enema (DCBE). CTC of twenty asymptomatic individuals (M:F = 10:10) participating to a colorectal cancer screening program and DCBE of fifteen patients (M:F = 6:9) were evaluated. For CTC, absorbed dose was determined by calculating the dose-length product for each CTC examination from measurements on a CT dose phantom equipped with a CT ion chamber. For DCBE, the free-in-air Kerma at the patient's X-ray entry surface and the Kerma-area product during fluoroscopy and fluorography were measured with a Barracuda system, with fluoroscopy times being recorded blinded to the performing operator. Effective dose at CTC was 2.17 ± 0.12 mSv, with good and excellent image quality in 14/20 (70%) and 6/20 cases (30%), respectively. With DCBE, effective patient dose was 4.12 ± 0.17 mSv, 1.9 times greater than CTC (P < 0.0001). Our results show that effective dose from screening CTC is substantially lower than that from DCBE, suggesting that CTC is the radiological imaging technique of the large bowel with the lowest risk of stochastic radiation effects.

Post-surgical follow-up of colorectal cancer: role of contrast-enhanced CT colonography.

AIM: To evaluate the role of CT colonography (CTC) in the follow-up of patients having received partial colectomy for colorectal cancer. METHODS AND MATERIALS: CTC was performed in 72 subjects with history of partial colectomy for colorectal cancer. Colectomy had been performed in the right colon (n = 18), descending colon (n = 15), sigmoid colon (n = 21), and rectum (n = 18). Patients underwent CTC following incomplete conventional colonoscopy due to intolerance to endoscope insertion or luminal stenosis. In 70 cases pneumocolon was obtained through a rectal tube, and in 2 cases through a cutaneous anastomosis. CTC datasets were analyzed in combined 2D and 3D mode. All patients in whom CTC was suggestive for or raised the suspicion of disease recurrence underwent colonoscopy in sedation for confirmation of CTC findings. RESULTS: CTC detected 7 cases of anastomotic stenosis. In 6/7 patients the stenosis was located in the sigmoid colon and in 1/7 patients at the level of the ileo-colic junction in the transverse colon. Out of these cases, four were fibrotic and three were neoplastic stenoses. In none of these cases was the CT appearance of the stenoses specific for disease recurrence, and conventional colonoscopy together with biopsy was necessary in order to characterize such findings. However, sensitivity of CTC in detecting anastomotic stenosis was 100% (7/7). One colonic mass (5 cm largest diameter) was detected in one case at the level of the proximal transverse colon in a patient with left colectomy performed 2 years before. The study of the residual colon showed 3 polyps in three patients (8, 6, and 5 mm, respectively). All CT findings were confirmed and characterized by conventional colonoscopy. In all cases the residual colon was entirely visualized by CTC with a completion rate of 100%. CONCLUSIONS: CTC is a feasible and minimally invasive method for full exploration of the colon after surgical resection allowing detection of cancer recurrence, metachronous disease, and distant metastases in one single study, and represents a valid alternative to conventional colonoscopy in this patient population.

Role of CT colonography in inflammatory bowel disease.

CT colonography (CTC), or virtual colonoscopy, is a non-invasive imaging method that uses CT data sets combined with specialized imaging software to examine the colon. CTC is not used routinely in patients with inflammatory bowel disease (IBD). However, investigating contemporarily the colon, other abdominal organs and the peritoneum with CTC is at times useful in patients with IBD, especially when other diagnostic tools fail. Furthermore, since symptoms of colorectal cancer sometimes superimpose to those of inflammatory disease, it may happen to image patients with IBD incidentally. If clinical signs are suggestive for inflammatory disease, exam technique should be modified accordingly and distinguishing radiological findings searched for.

CT colonography: same-day tagging regimen with iodixanol and reduced cathartic preparation.

The purpose of the study was to test the tagging performance and patient's acceptance of a reduced cathartic preparation, based on iodixanol and PEG, administered to patients 3 h before the exam. One hundred and thirty-two asymptomatic patients were enrolled. As colonic cleansing we used PEG macrogol 3350. For fluid tagging iodixanol was orally administered 3 h before the exam, in a total dose of 50 mL mixed with 34.8 g of PEG in 750 mL of water. Image's review showed 446 segments (56.4%) clean of feces and 346 segments (43.6%) with feces. Untagged fluid was observed in 74/706 (10.5%) segments; inhomogeneous tagging in 129/706 (16%); the average density of fluid was 1054.74 UH in the cecum-ascending colon and 905.14 UH in the descending-sigmoid colon; the average difference of density between right and left colonic segments was 149 UH, and it was statistically significant (P = 0.016). No side effects related to the consumption of Movicol were reported. Very few side effects related to the tagging solution were reported: mild nausea in 7 (0.05%) patients, mild diarrhea in 10 (0.07%). An average rank of 9 points (SD +/- 1) on a 10-point scale (10 = no discomfort, 0 = severe discomfort) resulted from the self-administered questionnaire, showing an excellent acceptance of the preparation. Same day fluid tagging with iodixanol provides an optimal fluid tagging, it is completely tolerated by the patient, and it can be performed under medical control.

Vasovagal reactions in CT colonography.

We describe the occurrence of vasovagal reaction in two patients who underwent CT colonography (CTC). The patients, asymptomatic, were submitted to CTC in one case after right colectomy and in one case for screening purposes. The vasovagal symptoms occurred after pneumocolon and acquisition in the prone decubitus, and included headache, hypotension, bradycardia, cold sweat and pallor, nausea, and diaphoresis. Abdominal pain was also referred. All symptoms resolved within 30 min to 3 h from their onset. In all cases the vasovagal reaction occurred after prone decubitus. CTC images showed a significant distension of the small bowel. Vasovagal reactions are potential complications of CTC.