Hypersensitivity reactions to iodinate contrast media in Italy: a retrospective study. Characteristics of patients and risk factors.

SUMMARY: Objective. The purpose of the study was to describe the characteristics of patients experiencing hypersensitivity reactions (HRs) to iodinated contrast media (ICM) in a large Italian population and to investigate potential risks factors in order to obtain a risk stratification, helpful in the management of these patients. Methods. Data of 407 patients investigated in 9 Italian Allergy Centers for suspected HRs to ICM were analyzed and compared with a control group of 152 subjects that tolerated one or more ICM-enhanced examinations. The univariate and multivariate logistic regression model was used to evaluate associated factors. Results. The mean age of reactive patients was 61 years and 60% were female; 67% of patients reported immediate reactions and 35% experienced the reaction, more frequently with immediate onset, at the first examination in life. Iomeprol, iopromide and iodixanol were the most frequent culprit agents and 20% of patients showed a positive skin test result. Previous adverse reactions to ICM were reported by 15.6% of patients, whereas 35% of subjects experienced the reaction, more frequently immediate, after the first ICM-enhanced examination in their life. The multivariate analysis showed that male gender and age > 65 were associated with ICM reactions as protective factors [ORadja = 0.51; 95% CI: 0.33-0.77 and ORadja = 0.60; 95% CI: 0.39-0.92 respectively]. Cardio-vascular disease [ORadja = 2.06; 95% CI: 1.22-3.50)], respiratory allergy [ORadja = 2.30; 95% CI: 1.09-4.83)] and adverse drug reactions [ORadja = 1.99; 95% CI: 1.05-3.77)] were identified as risk factors for ICM reactions. Food allergy was not significantly associated with reactions [ORadja = 1.51; 5% CI: 0.41-5.56]. Conclusions. This is the largest study on Italian patients experiencing hypersensitivity reactions to ICM. Most results are in line with other studies, showing some association with factors that could influence the incidence of hypersensitivity reactions but not allowing an easy risk stratification.

Comparison between magnetic resonance imaging and rigid rectoscopy in the preoperative identification of intra- and extraperitoneal rectal cancer.

AIM: Accurate preoperative discrimination between extra- and intraperitoneal rectal cancer has important treatment implications. Our main objective was to compare the diagnostic performance of MRI with rigid rectoscopy (RRS) in assessing the location of rectal cancers above or below the peritoneal reflection (PR), using the findings obtained during abdominal surgery for treatment of the cancer as the reference standard. We also compared the accuracy of MRI and RRS in assessing the level of the lower border of the tumour from the anal verge. METHOD: Patients with rectal carcinoma awaiting surgery underwent MRI and RRS. The MRI images were reviewed by two abdominal radiologists who determined the location of the inferior border of the tumour in relation to the PR. Receiver-operating characteristics (ROC) curve analysis was performed to determine the diagnostic performance of RRS at different cut-off values. RESULTS: The sensitivity and specificity were 98.15% and 100%, respectively, for MRI, and 100% and 76.92%, respectively, for RRS at a cut-off value of < 10 cm. The mean level of the lower border of the tumour from the anal verge was 68 ± 44.3 mm on RRS and 73.5 ± 42.4 mm on MRI (P = 0.25), with a trend towards overestimation with MRI. CONCLUSION: RRS is still the main means of assessing the level of a rectal tumour from the anal verge, but MRI has value in determining the level of the tumour in relation to the PR, which cannot be seen on endoscopy.

Measurement of liver iron overload: noninvasive calibration of MRI-R2* by magnetic iron detector susceptometer.

An accurate assessment of body iron accumulation is essential for the diagnosis and therapy of iron overload in diseases such as thalassemia or hemochromatosis. Magnetic iron detector susceptometry and MRI are noninvasive techniques capable of detecting iron overload in the liver. Although the transverse relaxation rate measured by MRI can be correlated with the presence of iron, a calibration step is needed to obtain the liver iron concentration. Magnetic iron detector provides an evaluation of the iron overload in the whole liver. In this article, we describe a retrospective observational study comparing magnetic iron detector and MRI examinations performed on the same group of 97 patients with transfusional or congenital iron overload. A biopsy-free linear calibration to convert the average transverse relaxation rate in iron overload (R(2) = 0.72), or in liver iron concentration evaluated in wet tissue (R(2) = 0.68), is presented. This article also compares liver iron concentrations calculated in dry tissue using MRI and the existing biopsy calibration with liver iron concentrations evaluated in wet tissue by magnetic iron detector to obtain an estimate of the wet-to-dry conversion factor of 6.7 ± 0.8 (95% confidence level).

Crohn's disease: prevalence of intestinal and extraintestinal manifestations detected by computed tomography enterography with water enema.

BACKGROUND: Computed tomography enterography (CTE) may detect the presence, severity, and extent of bowel inflammation in patients with Crohn's disease (CD). The aim of our study was to assess, among a cohort of 22 histologically proven CD patients, the prevalence of disease distribution, behavior, anastomotic recurrence and extraintestinal manifestations detected by an original CTE technique. METHODS: Two radiologists reviewed 221 CTEs performed providing both small and large bowel distension by oral administration of neutral contrast material and trans-rectal introduction of a water enema (CTE-WE). RESULTS: Ileal CD was detected in 116 CTE-WEs (52.4%), including 71/116 (61.2%) non-stricturing/non-penetrating, 17/116 (14.6%) stricturing, and 28/116 (24.1%) penetrating forms. Colonic CD was appreciable in 35 (15.8%) patients, including 18/35 (51.4%) non-stricturing/non-penetrating, 6/35 (17.1%) stricturing, and 11/35 (31.4%) penetrating forms. Ileocolic CD was present in 52 (23.5%) CTE-WEs, including 30/52 (57.7%) non-stricturing/ non-penetrating; 3/52 (5.7%) stricturing, and 19/52 (36.5%) penetrating forms. In 10/221 patients (4.5%), upper gastrointestinal involvement (UGI) was present. Perianal disease was observed in 17/221 patients (7.7%). Fistulas were present in 52 (23.5%) and abscesses in 24 (10.8%) CTE-WEs, respectively. Among 57/221 (25.8%) patients who had undergone a disease-related intestinal resection, in 30/57 cases (52.6%) CD recurrence at the anastomosis was present. 4/221 patients (1.8%) with a histologically confirmed intestinal neoplastic stenosis were observed. Sacroiliitis (24%) was found to be prevalent over hepatic steatosis (10.8%), cholelithiasis (8.6%), and nephrolithiasis (4%). CONCLUSIONS: CTE-WE represents a comprehensive imaging technique which may demonstrate bowel inflammation and CD extraintestinal manifestations. A peculiar prevalence of UGI involvement and neoplastic strictures were observed. In our study the prevalence of sacroiliitis resulted higher than previously reported.

Multidetector computerized tomography enteroclysis vs. rectal water contrast transvaginal ultrasonography in determining the presence and extent of bowel endometriosis.

OBJECTIVES: To compare the accuracy of multidetector computerized tomography enteroclysis (MDCT-e) and rectal water contrast transvaginal ultrasonography (RWC-TVS) in determining the presence and extent of bowel endometriosis. METHODS: This prospective study included 96 patients of reproductive age with suspicion of bowel endometriosis. Patients underwent MDCT-e and RWC-TVS before operative laparoscopy. Findings of MDCT-e and RWC-TVS were compared with histological results. The severity of pain experienced during MDCT-e and RWC-TVS was measured by a 10-cm visual analog scale. RESULTS: Fifty-one patients had bowel endometriotic nodules at surgery. Sensitivity, specificity, positive predictive value, negative predictive value and accuracy for the diagnosis of rectosigmoid endometriosis were 95.8% (46/48), 100.0% (48/48), 100.0% (46/46), 96.0% (48/50) and 97.9% (94/96) for MDCT-e and 93.8% (45/48), 97.9% (47/48), 97.8% (45/46), 94.0% (47/50) and 95.8% (92/96) for RWC-TVS. MDCT-e was associated with more intense pain than was RWC-TVS. CONCLUSIONS: MDCT-e and RWC-TVS have similar accuracy in the diagnosis of rectosigmoid endometriosis, but patients tolerate RWC-TVS better than they do MDCT-e.

Imaging of renal leiomyomas.

BACKGROUND: Renal leiomyomas are rare benign tumors of the kidney which can be found at autopsy as small capsular nodules in about 5% of cases. The clinical incidence of such lesions is much smaller, and only case reports or small series have been reported in the imaging literature. PURPOSE: To describe the imaging characteristics observed in a series of eight patients with pathology-proven asymptomatic leiomyomas of the kidney. MATERIAL AND METHODS: We reviewed the imaging findings observed in eight patients with pathologically proven asymptomatic renal leiomyomas discovered during studies performed for reasons unrelated to the kidney. All patients had undergone computed tomography (CT), two ultrasonography, and one magnetic resonance imaging (MRI). RESULTS: Lesions ranged in size from 1.2 to 13 cm. Six were at the periphery of the kidney, compressed its outer surface, but did not cause disruption of the cortex; two involved the renal cortex. All had regular outer margins. A cleavage plane between the tumor and the kidney was revealed at CT and/or ultrasonography in three of the cases located at the periphery. At ultrasonography, leiomyomas appeared hypoechogenic. At CT, they were slightly hyperdense before contrast medium injection; all were hypodense to the renal cortex after contrast medium. Four were homogeneous, two were slightly heterogeneous, and the remaining two were frankly heterogeneous. The lesion studied by MRI, which was homogeneous at the postcontrast CT study, had a heterogeneous structure on both T1- and T2-weighted images, with internal areas of hypointensity on T1. CONCLUSION: There are some imaging findings that can help to suggest the diagnosis of renal leiomyomas. First, their density: all tumors examined before contrast were hyperdense to the kidney, with density similar to that of muscles, and all had lower enhancement than the adjacent renal parenchyma. Second, the location and margins of the tumors: most were peripheral, without involvement of the renal cortex and with well-defined margins. Although not pathognomonic for a renal leiomyoma, the combination of these findings should include leiomyoma in the list of differential diagnoses.

Characterization of benign hepatic tumors arising in fatty liver with SonoVue and pulse inversion US.

BACKGROUND: We describe the spectrum of contrast-enhancement patterns of benign hepatic tumors arising in fatty liver on contrast-enhanced ultrasound (US). METHODS: Sixteen patients (12 women and four men) with 27 benign hepatic tumors (17 hemangiomas, eight focal nodular hyperplasias, and two hepatocellular adenomas) arising in fatty liver underwent baseline and pulse inversion US after administration of SonoVue. Two experienced radiologists evaluated baseline echogenicity and dynamic enhancement pattern of each lesion in comparison with adjacent liver parenchyma. RESULTS: After administration of SonoVue, in the arterial phase 13 of 17 hemangiomas showed peripheral globular enhancement and one showed a rim of peripheral enhancement, followed by progressive centripetal fill-in, which was complete in 10 of 14 cases and incomplete in four. Three of 18 hemangiomas showed rapid and complete fill-in in the arterial phase. Eight of eight focal nodular hyperplasias became hyperechoic in comparison with adjacent liver parenchyma in the arterial phase and slightly hyperechoic or isoechoic in the portal venous and delayed phases. Both adenomas showed strong arterial contrast enhancement that became less intense in the portal venous and delayed phases. CONCLUSION: Contrast-enhanced US after administration of SonoVue enables depiction of typical contrast-enhancement patterns in most benign hepatic tumors arising in fatty liver, thus providing useful clues for characterization.

Multidetector-row CT enteroclysis: indications and clinical applications.

This paper examines the diagnostic potential of multislice computed tomography enteroclysis (MSCT-E) to detect and assess different diseases affecting the small bowel, emphasising the increasingly important role assumed by the technique in the study of this anatomical region. After a short summary of the technical aspects, we discuss the different findings that can be observed during an MSCT-E study and that enable detection of small-bowel disease and, if necessary, assessment of the extent and stage of disease.

Multidetector-row helical CT enteroclysis.

The authors illustrate the technique for small-bowel imaging using enteroclysis with multidetector-row computed tomography (MDCT), underscoring the important role played by CT in the assessment of the small bowel thanks to the advent of first the spiral and later the multidetector technique. The paper makes a detailed comparison of the various methods that have been used in CT study of the small bowel and proposes a standardised technique to achieve correct distension of bowel loops and adequate evaluation of bowel wall vascularity, making reference to the well-consolidated experiences of the various Italian research groups. The paper accurately describes the different procedures required for CT assessment of the small bowel, from nasojejunal intubation to the selection of the most appropriate acquisition phases for assessment of bowel wall vascularity.

Regarding six cases of mesenteric panniculitis: US, spiral CT, Magnetic Resonance.

PURPOSE: Mesenteric panniculitis is a rare inflammatory disease. The inflammation produces a lesion which appears as a mass, and normally produces abdominal pain without any other significant clinical signs. The radiological pattern is not typical, but the diagnosis is aided by a number of elements which are important to recognise in order to avoid invasive diagnostic methods or therapy. Six cases are presented, all evaluated with sonography, Color-Doppler US, Spiral CT and Magnetic Resonance Imaging (MRI). MATERIALS AND METHODS: We evaluated six patients with negative clinical histories and endoscopic examinations. The patients reported the recent onset of indefinite symptoms and abdominal pain treated at home. Abdominal plain film radiography, performed also in the upright position, was negative in all cases. All the patients underwent abdominal sonography and Colour-Doppler ultrasound. Spiral CT scanning was carried out with 5-mm slice thickness, a pitch of 1.3, and single breath-hold volumetric acquisitions starting 60 s after intravenous injection of iodinated contrast medium. Only in one case, where Crohn's disease was suspected and subsequently not confirmed, did we perform small bowel enema with transparent contrast medium to distend the bowel loops. MR imaging was performed using a medium-field 0.5 T magnet, T1-weighted Fast SE, T2-weighted Fast SE and Fast STIR sequences. We considered: the mass effect of the lesion; the presence of vascular infiltration; the presence of a peripheral pseudocapsule; the presence of perivascular loose tissue proper, having densitometric characteristics distinctive from the remaining fatty tissue of the diseased mesentery. RESULTS: In all cases ultrasound detected only an central abdominal mass. The fatty content of the mass, however, reduced US transmission, preventing the acquisition of more complete information. The color-Doppler US also produced little data, except some isolated colour spots within the mass. In no case did CT directly detect a peripheral pseudocapsule, although it did identify a difference in density between the perivisceral abdominal loose tissue and the mesentery proper, which is hyperdense. The vessels inside the mesentery on no occasion appeared infiltrated. The CT scans were unable to identify differential elements between the perivascular loose tissue and the fatty tissue of the main mass. MRI, on the other hand, enabled the detection of the peripheral pseudocapsule which surrounded the mesenteric mass as a band of tissue with low signal intensity in all the sequences performed. In fast STIR sequences suppression of the fat signal of the mesenteric mass was insufficient, being suppressed only in the adipose tissue surrounding the arterial branches of the mesenteric artery. Four of the six patients underwent exploratory laparotomy. The histological examination of the biopsies revealed a massive inflammatory infiltration of the mesentery, with relatively little involvement of the perivascular adipose tissue. CONCLUSIONS: In mesenteric panniculitis, sonography and spiral-CT are useful in focusing diagnostic attention on the mesentery, but only MRI is capable of providing the information necessary formulating a complete diagnosis of the disease.

[Spiral computerized tomography without perfusion of contrast media as first line investigation in patients with renal colic]. / La Tomografia Computerizzata spirale senza perfusione di mezzo di contrasto per venam come indagine di prima istanza nei pazienti con colica renale.

INTRODUCTION: We investigated the diagnostic accuracy of unenhanced helical CT in the detection of stones in patients with suspected renal colic from ureteral stones and compared CT findings with the results of plain abdominal film and US. MATERIAL AND METHODS: We reviewed the findings relative to 80 patients (age range 24-75) who came to our observation to the Emergency Department with acute flank pain. All patients had been examined with plain abdominal radiography, US and unenhanced helical CT. RESULTS: While abdominal radiography showed the presence of radiopaque stones in 38 patients only (47.5%), US demonstrated ureter dilatation in 72 patients and detected stones in 36 of them (45%). Helical CT performed best, depicting a stone in 72 patients (90%), with high sensitivity and specificity. Mean stone size was 3 mm, with 7 mm-1 mm range. The biggest stones were seen in 3 cases and the smallest ones in 34. In 8 patients with no signs of stones we found other extraurinary conditions, namely pancreatitis, diverticula, renal cancer. We also found a case of urinary tract infection. CONCLUSIONS: Thanks to its short execution time and accuracy, helical CT makes the examination of choice in patients with acute flank pain due to renal colic. It is also a most valuable tool in the differential diagnosis of other pathological causes of pain such as abdominal or pelvic masses and inflammatory conditions.

Spiral CT of the abdomen after distention of small bowel loops with transparent enema in patients with Crohn's disease.

BACKGROUND: [corrected] To evaluate the capability of a computed tomographic (CT) technique that combines distention of the small bowel loops with a transparent enema with contrast-enhanced spiral CT of the abdomen in patients with Crohn's disease. METHODS: We evaluated the abdomen with spiral CT after distention of the small bowel loops with a transparent enema of methylcellulose in 40 patients consecutively referred for radiologic evaluation of Crohn's disease of the small bowel. Fluid was infused through a nasojejunal catheter with a peristaltic pump. Ultrasonography was used to prevent bowel overdistention and detect arrival of methylcellulose to the cecum. Contrast-enhanced spiral CT of the abdomen was then performed, and the degree of contrast enhancement and the thickness of the walls of the involved loops were evaluated. A series of 10 patients with retrograde distention of the last ileal loop from large bowel water enema was used as a control. The results of the CT were compared with those of conventional radiographic small bowel studies. RESULTS: The normal small bowel wall was 1.9-2.5 mm thick (mean = 2. 1 mm); density values of the normal enhanced wall varied between 25 and 60 HU (mean = 32 HU) and presented a homogeneous structure. Bowel segments involved by the disease were 4-12.5 mm thick (mean = 9.2 mm), had density values of 75-150 HU (mean = 105 HU), and showed a multilayered appearance. Compared with conventional radiography, CT detected longer lesions or additional segments involved by the disease process in 14 cases, 11 additional fistulas, two abscesses, and mesenteric changes in 21 cases. CONCLUSIONS: The small bowel CT enema technique provides good results in the study of patients with Crohn's disease and can be used to evaluate patients with advanced lesions.

[Study with thoracic and abdominal spiral CT in intensive care unit patients]. / Studio mediante TC spirale del torace e dell'addome nei pazienti ricoverati nei reparti di rianimazione.

INTRODUCTION: The severe clinical conditions of intensive care unit patients need frequent imaging studies to detect the pathologic changes in the patients' situation and to plan the correct therapeutic management. The yield of bedside plain radiography is often not diagnostic but moving the patients to the radiology department could affect their clinical conditions. Conventional CT is difficult to perform in these patients because they need continuous assistance and cannot cooperate during the diagnostic examination. MATERIAL AND METHODS: The authors examined with Spiral CT 46 unconscious patients in poor clinical conditions who presented a variety of pulmonary and abdominal diseases. Thirty coma patients were submitted to bedside chest radiography and then to Spiral CT because there was disagreement between the radiographic and the clinical findings. Sixteen patients with abdominal conditions underwent Spiral Ct, 11 of them after bedside US. The chest and abdomen were examined with Spiral CT in 2/16 patients and the abdomen only in 5 cases; twenty-two of 46 patients were under assisted ventilation. During all the Spiral CT studies, the patients had their arms along the body. Spiral CT results were compared with those of bedside chest radiography in 30 cases and with those of bedside abdominal US in 11 patients. DISCUSSION AND CONCLUSIONS: Spiral CT is a fast examination technique with no major artifacts which can be used safely also in unconscious patients. It confirmed a variety of pathologic conditions which may be misdiagnosed by conventional chest radiography, which improves the care of these patients. Bedside plain radiography is limited by several factors depending on the patient (no cooperation, variable respiration, still decubitus), the examination technique (X-ray projection, exposure, poor diagnostic yield), and the anatomical region of interest (mediastinal vessels). Even though our technical standard for conventional radiography was high, Spiral CT was better in detecting parenchymal consolidation and pleural effusion, a missed pneumothorax or thromboembolic disease. We always performed Spiral CT when the clinical findings did not match the results of bedside plain radiography. Moving the patients was very easy because the intensive care unit in our hospital is in the same building as the radiology department and there were dedicated devices supporting the coma patients.

Imaging of patients with pancreaticobiliary diversion for obesity: post-operative anatomy and findings in small bowel obstruction.

Pancreaticobiliary diversion is a surgical procedure undertaken for obesity. It consists of a distal gastrectomy with a long Roux-en-Y reconstruction, the enteroenterostomy being placed 200 cm distal to the gastroenterostomy and 50 cm proximal to the ileocaecal valve. Three intestinal limbs are recognized: (a) the alimentary loop from the gastroenterostomy to the enteroenterostomy; (b) common loop from the enteroenterostomy to the ileocaecal valve and (c) pancreaticobiliary loop from the duodenum to the enteroenterostomy. The radiological findings in 15 pancreaticobiliary diversion patients with small bowel obstruction were reviewed (15 plain abdominal radiographs, 13 ultrasound (US), 8 CT) and compared with 20 plain abdominal radiographs, 10 US, and 10 CT studies performed for other causes in patients with pancreaticobiliary diversion and 15 CT scans from non-operated patients. After pancreaticobiliary diversion the pancreaticobiliary loop was completely air-free. In the patients operated on more than 1 year previously, alimentary and common loops were significantly larger than the pancreaticobiliary loop and small bowel loops of non-operated subjects. Obstruction of the pancreaticobiliary loop arrests only the flow of pancreaticobiliary secretions with non-specific clinical findings. Plain abdominal radiographs were not diagnostic in all but two cases with radiographically detectable dilated fluid filled loops. Air-fluid levels were never apparent. US and CT showed markedly dilatated intestinal loops and duodenum. Obstruction of the alimentary and common loops presented with symptoms, clinical signs, and radiological findings more typical for bowel obstruction in intact subjects.

Interlobular vasculature in renal transplants: a power Doppler US study with MR correlation.

PURPOSE: To evaluate, with power Doppler (PD) ultrasound (US), the normal interlobular vasculature in patients who underwent renal transplantation and to assess if defects of the PD signal at the interlobular level correspond to cortical areas that lack blood perfusion at magnetic resonance (MR) imaging. MATERIALS AND METHODS: Thirty-two normal and 33 malfunctioning transplanted kidneys were studied with PD US (6.5 MHz). PD images of interlobular vessels were graded on a scale of normal (pattern I) and decreasing visualization. In kidneys with focal (pattern II) and diffuse (pattern III) absence of interlobular signal, correlative dynamic MR imaging was performed. RESULTS: Interlobular vessels were consistently depicted with PD US in the proximal cortex of normally functioning transplanted kidneys. Of kidneys with a pattern II appearance, five had no contrast material enhancement in the cortical sites in which the interlobular PD signal was detected and three were contrast enhanced but it was less intense than that in adjacent cortical sites with normal interlobular vasculature. All transplanted kidneys with a pattern III appearance had delayed contrast enhancement. CONCLUSIONS: Although PD US appears to depict the interlobular vasculature up to the renal capsule, care should be taken in the diagnosis of perfusion defects, since absence of detectable flow at the interlobular level does not always correspond to cortical areas that lack perfusion on MR images.