Multiparametric MR imaging of the prostate at 1.5-T without endorectal coil using an 8 channel pelvic phased array: Is it still a viable option?

INTRODUCTION: The purpose of our work was to evaluate the feasibility of prostate multiparametric MR imaging at 1.5-T without endorectal coil using an 8 channel pelvic phased array coil. MATERIAL AND METHODS: A total of 154 patients who underwent mp-MRI were retrospectively included. Patients received a standardized mp-MRI, compliant with 2012 European Society of Uro-Radiology guidelines, with 1·5 T magnetic field strength and an 8 channel pelvic phased-array coil. Two blinded readers graded the image quality of mp-MRI on a three-point scale and they scored the prostate lesions according to PI-RADS v2. All PI-RADS of 4 or 5 underwent biopsy. A third radiologist and a pathologist verified the correspondence between the MRI images and the results of the biopsy. RESULTS: 64 (41.6%) patients showed a Pi-rads of 4 or 5. At biopsy, 79.7% showed a Gleason score ≥7, 12.5% showed a Gleason score of 6 and 7.8% showed a negative biopsy. In the group of Pi-rads ≤ 3, 12 patients underwent a biopsy with the following results: negative biopsy in 33.3%, atypical Small Acinar Proliferation in 16.7%, prostatic intraepithelial neoplasia in 25% and indolent PCa 25%. Mp-MRI in the identification of clinically significant cancer provided a low percentage of false positive (7.8%) while in 79.7% of cases it was capable to detect clinically significant prostate cancer. In 92.2% of patients mp-MRI identified a prostate cancer with a Gleason score ≥6. The inter-reader agreement was excellent in defining both the quality of the examination and the PI-RADS category (k = 0.83 and k = 0.70, respectively). CONCLUSIONS: mp-MRI at 1.5-T without endorectal coil using an 8 channel phased array is an appropriate tool for early detection of clinically significant prostate cancer. IMPLICATIONS FOR PRACTICE: 8 channel pelvic phased array is still an appropriate tool for early detection of clinically significant prostate cancer and for obtaining a reduction in overdiagnosis of indolent PCa.

MR-enterography with diffusion weighted imaging: ADC values in normal and pathological bowel loops, a possible threshold ADC value to differentiate active from inactive Crohn's disease.

OBJECTIVE: The aim of our study was to compare the apparent diffusion coefficient (ADC) values of pathological bowel loops wall (pADC) with the ADC values of normal appearing ones (naADC) and to determine a discriminating threshold. PATIENTS AND METHODS: 60 patients were studied at our Institution through a MR-enterography that included free-breathing axial Diffusion Weighted Imaging (DWI) with two b (0 and 800 s/mm2) after histological diagnosis of active Crohn's disease (CD). The one (when unique) or the best analyzable (when multiple) pathological bowel loop was identified in each patient, on the basis of the MRI features: wall thickness, presence of mural oedema and wall contrast enhancement after contrast medium administration. A normal appearing bowel loop was used for comparison. ADC values were measured in consensus by two radiologists, and they were compared with t-test. The ADC threshold value for the differentiation between pathological and normal appearing bowel loops was determined. RESULTS: The pADC values were significantly lower than the naADC values (1.48 ± 0.058 x 10-3 mm2/s versus 3.525 ± 0.07 x 10-3 mm2/s; p < 0.05). A threshold of 2.416 x 10-3 mm2/s showed 100% sensitivity and 100% specificity for the discrimination between normal and pathological bowel loops. CONCLUSIONS: In patients with active CD the ADC values of the pathological bowel wall are significantly lower than those of normal appearing bowel loops. A threshold of ADC value of 2.416 10-3 mm2/s could discriminate normal from pathological bowel loops.

Clinical implications of different calculation algorithms in breast radiotherapy: a comparison between pencil beam and collapsed cone convolution.

BACKGROUND: This investigation focused on the clinical implications of the use of the Collapsed Cone Convolution algorithm (CCC) in breast radiotherapy and investigated the dosimetric differences as respect to Pencil Beam Convolution algorithm (PBC). MATERIAL AND METHODS: 15 breast treatment plans produced using the PBC algorithm were re-calculated using the CCC algorithm with the same MUs. In a second step, plans were re-optimized using CCC algorithm with modification of wedges and beam weightings to achieve optimal coverage (CCCr plans). For each patient, dosimetric comparison was performed using the standard tangential technique (SWT) and a forward-planned IMRT technique (f-IMRT). RESULTS: The CCC algorithm showed significant increased dose inhomogeneity. Mean and minimum PTV doses decreased by 1.4% and 2.8% (both techniques). Mean V95% decreased to 83.7% and 90.3%, respectively for the SWT and f-IMRT. V95% was correlated to the ratio of PTV and lung volumes into the treatment field. The re-optimized CCCr plans achieved similar target coverage, but high-dose volume was significantly larger (V107%: 7.6% vs 2.3% (SWT), 7.1% vs 2.1% (f-IMRT). There was a significantly increase in the ipsilateral lung volume receiving low doses (V5 Gy: 31.3% vs 26.2% in SWT, 27.0% vs 23.0% in f-IMRT). MUs needed for PTV coverage in CCCr plans were higher by 3%. CONCLUSIONS: The PBC algorithm overestimated PTV coverage in terms of all important dosimetric metrics. If previous clinical experience are based on the use of PBC model, especially needed is discussion between medical physicists and radiation oncologists to fully understand the dosimetric changes.

Uterine inversion in association with uterine sarcoma: a case report with MRI findings and review of the literature.

Non-puerperal uterine inversion due to uterine sarcomas represents a very rare event with no reliable estimate of frequency in the literature. Clinically, the diagnosis of inversion may be difficult, as far as imaging procedures are concerned, although ultrasonography may prove to be useful. However, some characteristics such as the indentation of the fundic area and a depressed longitudinal groove extending from the uterus to the center of the inverted portion are difficult to recognize. Moreover, there is no specific computed tomography feature accurate enough to aid in the differential diagnosis. Here, we report a case of uterine inversion due to Müllerian uterine adenosarcoma whose preoperative workup and diagnosis took advantage of the application of magnetic resonance imaging.

Mammography before post-operative radiotherapy in conservatively managed breast cancer patients: is it useful?

OBJECTIVE: The aim of this study was to evaluate the role of bilateral mammography undertaken before adjuvant radiotherapy in patients with conservatively managed invasive carcinoma of the breast. METHODS: Patients with invasive breast cancer referred to the Radiotherapy Unit of the Università Cattolica del Sacro Cuore, in Campobasso, Italy, between March 2002 and September 2006 were retrospectively reviewed. Patients were referred to our facility from other local and regional hospitals where they received breast-conserving surgery and adjuvant chemotherapy. They presented to our department for post-operative whole-breast radiotherapy. All patients underwent physical examination and bilateral mammography prior to adjuvant irradiation. RESULTS: 201 patients met the selection criteria as delineated. Of these 201 patients who underwent pre-radiotherapy mammography, 3 had suspicious findings on mammography. In two of those cases, the histopathological examination confirmed the presence of residual disease within the residual mammary gland. In one case, the pre-radiotherapy mammogram allowed for the detection of disease persistence which was not otherwise appreciated on physical exam. In the other case, the diagnostic imaging confirmed only the findings of the physical exam. In both cases of residual disease, the tumour was found elsewhere in the breast and not at the primary site. In one patient, the radiological re-assessment led to a false-positive result. No cases of contralateral synchronous breast cancer were observed. The overall adjunctive cost of this strategy including a routine mammography besides the clinical visit was €7012 for all patients. CONCLUSIONS: No clear recommendation exists regarding post-operative mammography before adjuvant radiotherapy. In our experience, this strategy allowed for the detection of gross disease persistence after surgery which was not appreciated at clinical examination in 1 case out of 201. In this patient, adjuvant radiotherapy up to a total dose of 50 Gy would have been inadequate. Given the low cost of mammography, further investigation about its role in pre-radiotherapy evaluation is warranted.

Staged hybrid treatment of complex ascending aortic and distal aortic arch pseudoaneurysm after repair of aortic coarctation.

A 49-year-old operated for aortic coartaction patient presented with thoracic and ascending aortic aneurysm. He was asymptomatic. Angio-magnetic resonance nuclear scan and angiography revealed an ascending aortic aneurysm (5.2 cm), bicuspid aortic valve, 6-cm proximal descending aortic pseudoaneurysm at the site of the previous operation with involvement of the left subclavian artery. Restenosis at the original site of coarctation and aortic arch hypoplasia distally to the brachiocefalic trunk was also found. The operation performed was a "modified Bentall - De Bono". The pseudoaneurysm was not accessible through median sternotomy due to the massive lung adhesions following the previous surgery. The left common carotid artery was explanted from the aortic arch and connected with a graft to the ascending aortic conduit. A proximal neck suitable for landing zone of the endovascular stent-graft was then established. The postoperative course was uneventful. After two weeks, the patient was readmitted. The exclusion of the thoracic descending aortic pseudoaneurysm by endovascular implantation of the stent-graft prosthesis was performed. The left subclavian artery was excluded because left vertebral artery was closed. The patient did not develop hand claudicatio. The procedure was successful.

Role of CT scan-based and clinical evaluation in the preoperative prediction of optimal cytoreduction in advanced ovarian cancer: a prospective trial.

BACKGROUND: In advanced ovarian cancer, maximal efforts have to be attemptedto achieve optimal cytoreduction, as this represents the keystone in the therapeutic management. This large, prospective study aims at investigating the role of computed tomography (CT) scan in predicting the feasibility of optimal cytoreduction in ovarian cancer. METHODS: A total of 195 consecutive patients with clinical/radiographic suspicion of advanced ovarian/peritoneal cancer were enrolled at the Gynecologic Oncology Unit, Catholic University of Rome and Campobasso, Italy. Preoperative CT scans were performed with a high-speed scanner (CT Hi Speed Nx/i Pro; 2-slice; GE Medical System). All patients underwent standard laparotomy, and maximal surgical effort was attempted. The following CT parameters were used: peritoneal thickening, peritoneal implants >2 cm, bowel mesentery involvement, omental cake, pelvic sidewall involvement and/or hydroureter, suprarenal aortic lymph nodes >1 cm, infrarenal aortic lymph nodes >2 cm, superficial liver metastases >2 cm and/or intraparenchimal liver metastases any size, large volume ascites (>500 ml). Clinical data included were age, Ca125 serum levels, and ECOG-PS. Radiographic and clinical features exhibiting a specificity >75%, a positive and negative predictive value >50%, an accuracy >60% in predicting surgical outcome were assigned a point value of 2. With this scoring system, a predictive index (PI) was calculated for each patient. RESULTS: The PI scores ranged from 0 to 6, and from 0 to 8, in Model 1 (including only radiographic parameters) and in Model 2 (including radiographic and clinical data). The AUC was 0.78+0.035 in Model 1, and 0.81+0.031 in Model 2. Therefore, the addition of ECOG-PS data led to the improvement of the diagnostic performances (z=2.41, P-value <0.05). CONCLUSIONS: Computed scan still represents a valid tool to predict ovarian cancer optimal cytoreduction; the predictive ability of a CT scan-based model is improved by integrating ECOG-PS data.

Evaluation of a web-based network for reproducible T2* MRI assessment of iron overload in thalassemia.

PURPOSE: To build and evaluate a national network able to improve the care of thalassemia, a genetic disorder in haemoglobin synthesis often associated with iron accumulation in a variety of organs, due to the continuous blood transfusions. METHODS: The MIOT (Myocardial Iron Overload in Thalassemia) network is constituted by thalassemia and magnetic resonance imaging (MRI) centers. Thalassemia centers are responsible for patient recruitment and collection of anamnestic and clinical data. MRI centers have been equipped with a standardized acquisition technique and an affordable workstation for image analysis. They are able to perform feasible and reproducible heart and liver iron overload assessments for a consistent number of thalassemia patients in a robust manner. All centers are linked by a web-based network, configured to collect and share patient data. RESULTS: On 30th March 2008, 695 thalassemia patients were involved in the network. The completion percentage of the patient records in the database was 85+/-6.5%. Six hundred and thirteen patients (88%) successfully underwent MRI examination. Each MRI center had a specific absorption capacity that remained constant over time, but the network was capable of sustaining an increasing number of patients due to continuous enrollment of new centers. The patient's comfort, assessed as the mean distance from the patient home locations to the MRI centers, significantly increased during the network's evolution. CONCLUSION: The MIOT network seems to be a robust and scalable system in which T2* MRI-based cardiac and liver iron overload assessment is available, accessible and reachable for a significant and increasing number of thalassemia patients in Italy (about 420 per year), reducing the mean distance from the patient locations to the MRI sites from 951km to 387km. A solid, wide and homogeneous database will constitute an important scientific resource, shortening the time scale for diagnostic, prognostic and therapeutical evidence-based research on the management of thalassemia disease.

Postoperative ileus after para-aortic lymphadenectomy: a prospective study.

OBJECTIVE: To evaluate GI symptoms in patients submitted to systematic para-aortic lymphadenectomy (PALN) and to compare them in a contemporary series of patients only submitted to systematic pelvic lymphadenectomy (PLN). METHODS: A prospective study of 51 consecutive patients submitted to systematic (minimum number of aortic nodes removed > or =10) laparotomic para-aortic lymphadenectomy for any gynecological cancer. The following parameters have been monitored prospectively: nausea and vomiting, bowel movements, nasogastric tube insertion or reinsertion, the time of removal of the nasogastric tube, duration of ileus, time to first passage of stool, regular diet consumption and postoperative stay and complications. RESULTS: Twenty-three of 46 valuable patients (50%) submitted to systematic para-aortic lymphadenectomy complain of GI symptoms during recovery and 2 more cases have been readmitted for the appearance of nausea and vomiting with respect to 3 cases (5%) in the group of only pelvic lymphadenectomies (p=0.00001). According to multivariate analysis, the main determinant of post/operative GI dysfunction is the systematic aortic lymphadenectomy. Twenty-two out of a total of 28 symptomatic patients (78.6%) have accused mild symptoms and have been therefore treated by fasting, by intravenous fluid administration and by anti-emetic drugs. Out of the six remaining patients, three patients (10.7%) have been classified as moderate cases because they have required the insertion of a nasogastric tube for gastric decompression, whereas in the remaining refractory patients (10.7%, severe cases) prokinetics drugs have been used. An exploratory laparotomy has never been performed. CONCLUSIONS: GI dysfunction symptoms are very common in patients submitted to systematic para-aortic lymphadenectomy. However, only 20% of the patients complain about moderate/severe symptoms. In these cases, we strongly recommend a conservative management.

Intraluminal brachytherapy without stenting in intrahepatic papillary cholangiocarcinoma: a case report.

A 46-year-old female patient, with mild cholestasis by a large papillary cholangiocarcinoma involving the left hepatic duct, received intraluminal brachytherapy (50 Gy at 1 cm from the source axis) with the aim to relieve biliary obstruction without stent positioning. The patient presented with haemobilia and vegetant lesions in the left main biliary duct, and thus she had a high risk of early stent obstruction. Eighteen months after the treatment the patient presented tumour progression in the controlateral hepatic lobe, but had a patent left hepatic duct, without signs of cholestasis and/or cholangitis. Based on this and other published reports, intraluminal brachytherapy may be tested in a setting different from standard setting with the aim to safely palliate jaundice in patients with intraductal tumour growth in the biliary tract.

Hypercreatininemia and hyperglycemia: diabetic nephropathy or "inverted peritoneal auto-dialysis"?

We describe a case of 51-year-old male with fever, abdominal pain and inguino-scrotal hernia. Laboratory examination revealed hypercreatininemia and hyperglycemia, firstly interpreted as diabetic nephropathy. US and CT scan showed a hernia of the bladder into the scrotum. Surgery revealed multiple bladder perforations with peritoneal diffusion of urine. So, hypercreatininemia was caused by peritoneal reabsorption of urea and creatinine, a condition that may be described as "inverted peritoneal auto-dialysis". Surgical reposition and repairment of the bladder led to rapid normalization of serum urea and creatinine. Discharged diagnosis was intraperitoneal rupture of inguino-scrotal hernia of the bladder in patient with recent onset of diabetes mellitus.

Comparison between color power Doppler ultrasound with echo-enhancer and spiral computed tomography in the evaluation of hepatocellular carcinoma vascularization before and after ablation procedures.

OBJECTIVE: Use of new echo enhancers capable of passing the lung filter has extended the clinical applications of color power Doppler flow imaging in many diseases and appears promising in the study of neoplasm vascularization. Levovist (Shering, Berlin Germany) is an ultrasound contrast agent containing galactose microbubbles suspended in palmitic oil. The sensitivity of Levovist-enhanced color power Doppler was compared to that of standard color power Doppler and contrast-enhanced spiral computed tomography (CT) in the detection of vascular signals in hepatocellular carcinoma. METHODS: We examined 29 hepatocellular carcinoma nodules in cirrhotic livers that had appeared avascular on unenhanced color power Doppler. Color power Doppler studies were repeated with and without Levovist enhancement before (15 examinations) and/or after (23 examinations) percutaneous ablation procedures. Findings (vascularized vs nonvascularized) were compared to those obtained with contrast-enhanced spiral computed tomography (gold standard) performed no more than 24 h after each of the 38 Doppler examinations. RESULTS: In pretreatment studies, Levovist-enhanced power Doppler correctly revealed vascularization in 12 of 15 lesions that had appeared avascular without echo enhancement and confirmed the avascularity of one other nodule; the remaining two, which appeared avascular on contrast-enhanced Doppler, displayed vascularization on the spiral CT examination. Levovist-enhanced power Doppler was fully concordant with spiral CT findings in all of the posttreatment examinations. CONCLUSION: Considering the absence of false positive results in this study, echo-enhanced color power Doppler can be considered reliable in diagnosing incomplete necrosis of hepatocellular carcinomas after percutaenous ablation. Spiral computed tomography can thus be reserved for those cases in which the enhanced power Doppler examination reveals no evidence of vascularity.

High resolution spiral computed tomography of the pancreas.

Computed tomography (CT) is a very useful tool in the assessment of pancreatic disease. Searching for subtle signs, as in chronic pancreatitis or staging of adenocarcinoma, high spatial and contrast resolution is needed. The high resolution computed tomography (HRCT) technique for pancreatic scans, and its evolution from dynamic CT to multislice spiral CT, is described. 2D and 3D dimensional reconstructions are depicted and their role in diagnosis is focused. Together with spatial resolution, contrast enhancement protocols are discussed, aimed to achieve optimal contrast between the lesion and normal parenchyma.

[Evaluation of the "N" factor in nonsmall cell lung cancer. Correlation between computerized tomography and pathologic anatomy]. / Valutazione del fattore "N" nel carcinoma polmonare non a piccole cellule. Correlazione tra Tomografia Computerizzata e anatomia patologica.

PURPOSE: To evaluate the role of CT in identifying other morphological signs of metastatic lymph node involvement from non small cell bronchogenic carcinoma. This is done to improve N staging, a critical step in this disease. In fact, since diameter is the only criterion used to distinguish normal form abnormal lymph nodes, medistinal CT only has 80% diagnostic accuracy. MATERIAL AND METHODS: 137 patients with known or suspected lung cancer were examined with Helical CT during early and late arterial phases (2 min delay, 3 mm thickness, 5 mm interslice gap) to depict node characteristics. Mediastinal lymph nodes, located according to the American Thoracic Society mapping, were considered normal when they were not visible or, if visible, less than 1 cm in diameter and of homogeneous density; lymph nodes over 1 cm in diameter and homogeneous density were considered reactive. A lymph node was considered metastatic when, independent of size, the following signs were found: central hypodensity; hyperdense thin/thick rim, with nodules within; hyperdense strands or diffuse hyperdensity in perinodal adipose tissue. The tumor site was also considered. RESULTS: Seventy patients were excluded because they were inoperable. Sixty-five of the remaining 67 patients were operated on, 1 underwent mediastinoscopy and another one mediastinoscopy followed by surgery. Based on the above CT signs, 46 patients were staged as N0, 61 as N1 and 15 as N2. In 44/46 N0 patients there was agreement between anatomical and pathologic findings; 3 of the 44 patients had lymph nodes over 1 cm in diameter and with homogeneous density. Micrometastases to mediastinal lymph nodes (N2) were found at histology in 2/46 patients (CT false negatives). In the 6 N1 and the 15 N2 patients there was complete agreement between anatomical and pathologic findings; in particular, 9 N2 patients had lymph nodes less than 1 cm in diameter with signs of metastasis and 4 had lymph nodes over 1 cm in diameter with signs of metastasis and 2 had lymph nodes either over or less than 1 cm. In all N2 patients the tumor histotype and the mediastinal location were also considered relative to the lesion site. DISCUSSION: A closer correlation was found with node morphology and density than with size. Indeed, CT sensitivity, specificity and diagnostic accuracy were 97, 100 and 97%, respectively, for the former versus 52, 93 and 77% for the latter. Adenocarcinoma was the predominant histotype (70.5%) in N2 patients. Metastases to node region 4 were predominant in right upper lobe carcinomas while node region 5 was predominant in left upper lobe lesions. CONCLUSIONS: Other criteria can be associated with size to improve CT diagnostic accuracy in N staging. Technique optimization plays a major role particularly in the late, thin slice, examination phase.

Lymphatic system: morphofunctional considerations.

The lymphatic system, consisting of the lymph nodes and the lymphatic vessels as well as the spleen and various sites of lymphoid tissue, is deputed to important tasks: the immune response, the transport of lipids absorbed at the intestinal level and the reabsorption of water and other substances from the interstitial spaces; the lymph nodes in particular are involved in immunity and lymph filtration-depuration. Therefore, the knowledge of lymph node cellular architecture as well as of the structure and course of lymphatic vessels is of great importance. The pathologic processes that affect the lymphatic system can involve the canalicular and/or nodal part, resulting in patterns directly correlated with their respective function: lymphedema and lymphagitis on one hand, and disorders induced by accumulation, inflammation and tumors, on the other.

Combined diagnostic imaging of mediastinal lymphadenopathy in lung cancer.

The identification and characterization of lymphadenopathies is one of the fascinating challenges of modern diagnostic imaging. At present, the real problem is the distinction between normal and pathologic signs. For twenty years, the differentiation was based on the dimensional criterion, namely a short axis < 1 cm, however it was shown to be inadequate. After an overview of the anatomy, ATS classification, the role of N factor in lung cancer (60% of N0 patients survive at 5 years) while only 20% of N2 patients survive), the new signs evidenced on CT are analyzed and interpreted. With thin section, late phase CT, a retrospective study and a perspective study were carried out on densitometric changes in lymph nodes correlated with histology findings. The role of intranodal hypodensity, peripheral rim and adipose tissue was stressed. The results of these studies were concordant with histology findings and confirmed the better accuracy in staging and the impact on survival of extranodal spread detected, based on radiologic criteria.

Diagnostic imaging of primitive neuroectodermal tumour of the chest wall (Askin tumour).

OBJECTIVES: To describe the radiological features of primitive neuroectodermal tumour (PNET) of the chest wall (Askin tumour) at diagnosis and to analyse the radiological changes occurring as a consequence of treatment and during follow-up. MATERIALS AND METHODS: Nine children with histologically proven PNET were studied. At diagnosis, all patients underwent chest X-ray (CXR), chest CT and bone scintigraphy; three patients also had MR and three had US. During treatment and follow-up, CT was performed in all patients. RESULTS: CT demonstrated a solid heterogeneous chest wall mass in all children at diagnosis and six had a rib lesion. Small nodular densities in the extra-pleural fat were identified in three patients at diagnosis. US, performed in three patients, excluded tumour infiltration of the lung or diaphragm, which had been suspected on CT. On MR, the lesions showed high signal intensity in T1-weighted/proton-density images and intermediate/high signal intensity in T2-weighted images compared with muscle. Minimal chest wall involvement was demonstrated in one case by MRI. Extensive necrosis of tumour mass with pseudo-cystic appearance was documented in the five patients who underwent chemotherapy. Macroscopically complete resection was performed in five patients but there was early local recurrence after surgery in two, identified by CT in one and by MR in the other. CONCLUSIONS: PNET of the chest wall should be considered in a child with a chest wall mass. CT is valuable for evaluating tumour extension at diagnosis, the effects of chemotherapy and assessing tumour recurrence after surgery. However, CT can overestimate pleural, lung or diaphragmatic infiltration, which are better evaluated by US. MR was superior to CT in the evaluation of tumour extension in one of three patients and may be considered complementary to CT, particularly in very large chest wall tumours.

Carcinoma of the pancreatic head area. Diagnostic imaging: computed tomography.

CT is at present considered the most accurate procedure in the staging of tumors of the pancreatic head area. Accuracy is based on a rigorous exam performed either with a conventional equipment or with spiral CT. Basic signs and symptoms and staging criteria according to TNM classification are analyzed. Comparison with other imaging methods is made based on a review of the literature. The role of a high resolution procedure is stressed especially in case of vascular infiltration, the determining factor to indicate resectability. In this respect CT is still to be considered the most reliable method.

Combined modality staging of low risk rectal cancer.

The work-up conducted in order to reach a correct diagnosis based on a combined modality staging in patients with low risk rectal cancer, is presented. The diagnostic accuracy of each imaging technique is analyzed by the comparison of the radiologic TN with the histologic TN in 13 patients directly referred to surgery based on combined modality staging. Control with histologic findings has staged as T1-T2 13 patients directly referred to surgery, while only a patient was shown to have microinfiltration of perirectal fat. As for T, diagnostic accuracy was 90% for transrectal US, 66% for MRI, 61% for CT. Accuracy of transrectal sonography in the differentiation of T1 from T2 was 70% with a trend towards overstaging. None of the procedures has suggested the presence of metastatic lymph nodes while on histology small neoplastic foci were evidenced in a normal-sized perirectal lymph node. The high diagnostic accuracy of US in the definition of T in rectal cancer is confirmed. It is underlined that no procedure enables the detection of neoplastic microinfiltration of normal lymph nodes.