European Radiology

Bartolozzi, Carlo; Cioni, Dania; Donati, Francescamaria; Lencioni, Riccardo

doi: 10.1007/s003300100845pmid: 11519546

Magnetic resonance signal intensity of focal liver lesions is affected by numerous pathologic factors. Lesion histologic features, such as cellularity, vascularity, stromal component, and intratumoral necrosis or hemorrhage, strongly affect T1 and T2 relaxation times. Additionally, intracellular content of certain substances, such as glycogen, fat, melanin, iron, and copper, may also have a substantial role in determining MR signal behavior. In this review we discuss the correlations between MR imaging features and pathologic findings in benign and malignant focal liver lesions. Knowledge of imaging–pathology correlations greatly assist in characterizing focal lesions. Moreover, in certain tumor histotypes, such as hepatocellular carcinoma, careful analysis of lesion signal intensity may help predict the degree of tumor differentiation.

Högemann, Dagmar; Flemming, Peer; Kreipe, Hans; Galanski, Michael

doi: 10.1007/s003300000750pmid: 11519547

Hepatic angiomyolipomas are rare and often mimic other liver tumors. The aim of our study was to describe the CT and MRI findings and to correlate imaging features with histopathology. The CT and/or MR images were available for retrospective analysis in seven patients. Patients had non-enhanced as well as enhanced CT (n=6) or MRI (n=4) before and after administration of Gd-DTPA (n=2) or MnDPDP, a liver specific contrast agent, (n=3). In three patients CT and MRI did not detect fat, and in two patients the angiomyolipomas were also histopathologically devoid of fat. Vascularity ranged from hypervascular (n=4) with arteriovenous shunts (n=1) to equal (n=1) or less (n=2) post-contrast enhancement compared with the normal liver parenchyma. No uptake of the liver specific contrast agent, MnDPDP, was observed (n=3). Predominantly, CT and MRI did not include angiomyolipoma in the differential diagnosis, and the initial histopathological evaluation was inconclusive in more than half the cases. Hepatic angiomyolipomas frequently manifest as solitary well-circumscribed heterogeneous masses in patients with no underlying liver disease or elevation of serum tumor markers. If present, the demonstration of intratumoral fat is helpful in the diagnosis of angiomyolipoma. The final diagnosis can be obtained by immunohistochemistry.

Sandstede, Joern; Tschammler, Alexander; Beer, Meinrad; Vogelsang, Carsten; Wittenberg, Guenther; Hahn, Dietbert

doi: 10.1007/s003300000816pmid: 11519548

The aim of this study was to optimize bolus tracking for timing of the arterial phase of biphasic helical liver CT and to compare optimized bolus tracking to a standard delay. One hundred fifty patients were examined with six protocols: 5- or 10-s delay after triggering at a threshold of 50 or 75 or 100 HU enhancement in the aorta at the origin of the celiac arteries after injection of 120 ml contrast material at 3 ml/s. Optimal arterial enhancement was defined as 20–30% of hepatic enhancement in portal venous phase. Another 50 patients were examined with the optimized protocol and compared to 50 gender- and age-matched patients who underwent a 25-s standard delay. A 10-s delay after the 75-HU threshold resulted in the most patients with an optimal arterial phase (p<0.01). Thirty-one of 75 patients examined with this protocol showed optimal early liver enhancement. Bolus tracking compared with standard delay revealed only a trend for a difference (p=0.07). The outcome of automatic bolus tracking differs depending on the protocol used; however, optimal arterial phase imaging was seen in only 41% of patients, indicating only a trend for superior timing compared with a standard delay.

Eerens, Isabel; Vanbeckevoort, Dirk; Vansteenbergen, Werner; Van Hoe, Lieven

doi: 10.1007/s003300000742pmid: 11519549

Autoimmune pancreatitis is a relatively rare type of chronic pancreatitis that may be associated with other autoimmune disorders. The imaging features of this entity may be misleading and suggest the presence of a malignant tumour. We present a case in which MR imaging allowed us to diagnose autoimmune pancreatitis associated with primary sclerosing cholangitis, which is another autoimmune-related disease. Typical MR characteristics of autoimmune pancreatitis include focal or diffuse enlargement of the pancreas, the absence of parenchymal atrophy and significant dilation proximal to the site of stenosis, the absence of peripancreatic spread, the clear demarcation of the lesion and the presence of a peripancreatic rim.

Burkill, Guy; Bell, James; Healy, Jeremiah

doi: 10.1007/s003300100882pmid: 11519550

Small bowel obstruction is a leading cause of acute surgical admissions for abdominal pain. There is an increasing tendency for initial conservative management rather than immediate operative intervention, as a proportion of cases will resolve spontaneously. This has resulted in a growing reliance on radiological investigations to reassure the surgeon that medical therapy can be safely instituted. The onus therefore rests with radiologists to guide their surgical colleagues by correctly interpreting the plain abdominal radiograph and suggesting appropriate further investigation if warranted. Recently, computed tomography (CT) has been proposed as the test of choice to define the level and cause of acute small bowel obstruction and to identify complications such as ischaemia and perforation which will prompt surgical intervention. This review will discuss the utility of early CT in the diagnosis of acute small bowel obstruction and outline its impact on patient management.

Esteban, J.; Maldonado, L.; Sanchiz, V.; Minguez, M.; Benages, A.

doi: 10.1007/s003300000770pmid: 11519551

The aim of this study was to evaluate with colour Doppler ultrasound the vascular changes in the wall of the loops affected by Crohn's disease, and to establish whether these changes reflects clinical or biochemical activity of Crohn's disease. Seventy-nine patients with Crohn's disease (44 with active disease and 35 inactive patients) were studied with frequency- and amplitude-encoded duplex Doppler sonography. A group of 35 healthy volunteers were also included. The exam consisted of the search for colour signals in the walls of the loops affected by Crohn's disease, classifying the degree of vascularity with a simple scoring system into three groups: absence of colour signal (score of 0); weak or scattered colour signals (score of 1); and multiple colour signals or clear identification of vessels in the loops walls (score of 2). Doppler curves were obtained of the detected vessels with measurement of the resistive index (RI). There was a visible increase in the gut walls' vascularity in the active patients compared with those with inactive disease. The mean RI was statistically significantly lower in the gut wall vessels of the patients with active illness than that obtained in the inactive patients. Colour Doppler ultrasound is a useful tool in the assessment of activity in Crohn's disease.

Cittadini, Giuseppe; Gallo, Alessandra; De Cicco, Enzo; Giasotto, Veronica; Dogliotti, Luca; Cittadini, Giorgio

doi: 10.1007/s003300000782pmid: 11519552

The aim of the present study was to verify whether magnesium-induced increase of barium coating of the colonic mucosa is specifically due to the increase of barium suspension viscosity. One hundred sixty-one patients scheduled for double-contrast barium enema (DCBE) were randomised in one group of 23 patients (control group, CG), and three groups of 23 pairs (G1, G2 and G3), i.e. 138 patients. The DCBE was performed with standard technique using a barium suspension with dynamic viscosity of 280 cPs (CG), or with viscosity increased to 320 cPs (G1), 2500 cPs (G2) or 3200 cPs (G3), by extemporaneous addition of MgSO4 1, 2 or 3 g in one member of the pair, Na2SO4 1, 4.2 or 8 g in the other one. Three radiologists evaluated on an ordinal scale mucosal coating and free fluid. In all magnesium subgroups barium coating was better than in CG (p<0.008), the highest value being obtained in G2. No difference was observed as regards free fluid. Inside paired groups, mucosal coating was more effective in magnesium than in sodium members (p<0.0002). Viscosity of barium suspension being equal inside each group, this effect must be attributed to magnesium-specific interactions with additives of the barium suspension inducing events other than viscosity changes.

Mountanos, Ioannis; Manolakakis, Stilianos

doi: 10.1007/s003300000783pmid: 11519553

The accordion sign is a finding that could be seen on CT scans of the abdomen in patients who have received oral contrast material. Initially, it was described as a sign specific of Clostridium difficile colitis, but it is also reported to represent a sign of diffuse colonic edema of several other etiologies. We report a case of a patient with Crohn's pancolitis whose abdominal CT scan presented the accordion sign throughout the entire large bowel together with signs of Crohn's disease of the small bowel.

Tann, M.; Sopov, V.; Croitoru, S.; Nativ, O.; Moskovitz, B.; Bar-Meir, E.; Groshar, D.

doi: 10.1007/s003300000789pmid: 11519554

The aim of this study was to evaluate the accuracy of tumor size measurement on CT studies of renal tumors. Sixteen patients with tumors of the kidneys were imaged by helical CT prior to surgery. Assessment of tumor volume was made by two radiologists on the CT images with the summation of area method, then compared with the resected specimen water displacement volume. Intra- and interobserver agreement for CT measurements were also assessed. There were substantial differences between the CT volume measurement compared with the tumor post-operative volume (mean of differences 30.05±91.6, 95%CI: 31.45–91.55). The inter- and intraobservation agreements for tumor measurement by CT was found to be satisfactory (ANOVA: p<0.0001; t-test: p<0.05). The CT volumetric measurement by area summation is a method with good inter- and intraexamination reproducibility but not an accurate technique for tumor volume assessment.

Wiesner, W.; Ruehm, S.; Bongartz, G.; Kaim, A.; Reese, E.; De Geyter, C.

doi: 10.1007/s003300000777pmid: 11519555

The aim of this study was to evaluate the feasibility of three-dimensional dynamic MR hysterosalpingography (3D MR HSG) for visualization of the cavum uteri and demonstration of bilateral fallopian tube patency as an alternative to conventional hysterosalpingography. Five infertile female patients underwent 3D dynamic MR HSG prior to conventional hysterosalpingography. The MR protocol consisted of axial T1-weighted spin-echo (SE), axial/coronal T2-weighted fast SE (FSE), and 3D MR angiography sequences before, during, and after injection of a diluted gadolinium solution into the cavum uteri via a balloon catheter. Positioning of the catheter was feasible in all patients. In one patient the catheter slipped out during MRI and in one patient the catheter was placed far in the cavum uteri. In three patients catheter position was optimal at the level of the cervical canal. Evaluation of pelvic anatomy, myometrium, and ovaries was possible in all patients on the basis of T1-weighted SE and T2-weighted FSE. Three-dimensional visualization of the dilated cavum uteri was possible in four patients. In these four patients 3D MR HSG also proved bilateral fallopian tube patency which was confirmed in each patient by conventional hysterosalpingography. Three-dimensional MR HSG is feasible and further research should be done to determine if this technique can evolve into an alternative technique to conventional hysterosalpingography with the advantages of no radiation and additional visualization of the uterus wall and ovaries.