Michael R. Torkzad

Radiological findings do not support lateral residual tumour as a major cause of local recurrence of rectal cancer

The aim of this study was to determine the sites of local recurrence following radical (R0) total mesorectal excision (TME) for rectal cancer in an effort to elucidate the reasons for recurrence.

Interobserver and intraobserver variability in the response evaluation of cancer therapy according to RECIST and WHO-criteria

Abstract Background. Response Evaluation Criteria In Solid Tumors (RECIST) and WHO-criteria are used to evaluate treatment effects in clinical trials. The purpose of this study was to examine interobserver and intraobserver variations in radiological response assessment using these criteria. Material and methods. Thirty-nine patients were eligible. Each patients series of CT images were reviewed. Each patient was classified into one of four categories according RECIST and WHO-criteria. To examine interobserver variation, response classifications were independently obtained by two radiologists. One radiologist repeated the procedure on two additional different occasions to examine intraobserver variation. Kappa statistics was applied to examine agreement. Results. Interobserver variation using RECIST and WHO-criteria were 0.53 (95% CI 0.33–0.72) and 0.60 (0.39–0.80), respectively. Response rates (RR) according to RECIST obtained by reader A and reader B were 33% and 21%, respectively. RR according to WHO-criteria obtained by reader A and reader B were 33% and 23% respectively. Intraobserver variation using RECIST and WHO-criteria ranged between 0.76–0.96 and 0.86–0.91, respectively. Conclusion. Radiological tumor response evaluation according to RECIST and WHO-criteria are subject to considerable inter- and intraobserver variability. Efforts are necessary to reduce inconsistencies from current response evaluation criteria.

Magnetic resonance imaging and ultrasonography in diagnosis of pelvic vein thrombosis during pregnancy.

INTRODUCTION Pelvic deep vein thrombosis (DVT) is difficult to diagnose during pregnancy. In a two-center trial, we evaluated the agreement between ultrasonography and magnetic resonance imaging (MRI) in diagnosing the extent of DVT into the pelvic veins during pregnancy. MATERIALS AND METHODS Pregnant women with proximal DVT were examined both with ultrasound and MRI as part of a study designed for treatment of DVT during pregnancy. Ultrasound was performed using color flow by specialist in vascular ultrasound with Doppler and compression techniques. The MRI sequences consisted of a 2D Time of Flight angiography with arterial flow suppression and maximum intensity projection reconstructions; a 3D, T1-w-prepared gradient echo sequence with fat saturation for thrombus imaging; a steady-state free precession sequence; and a Turbo-Spin-Echo. No contrast agent was used. Proportion of agreement (kappa) for detection of DVT in individual veins was measured for different ipsilateral veins and inferior vena cava. RESULTS All 27 patients were imaged with both techniques at an average gestational age of 29 weeks (range 23-39). Three cases (11.5%) of DVT in the pelvic veins were missed on ultrasound but detected by MRI. The upper limit of the DVT was always depicted at a higher (20 cases, 65.4%) or the same level (seven cases, 34.6%) on MRI than on ultrasound. Agreement expressed as kappa was 0.33 (95% CI 0.27-0.40) demonstrating only fair agreement. In one woman the thrombus had propagated into the inferior vena cava, shown only on MRI. CONCLUSION Our study suggests that in pregnant women there is only fair agreement between ultrasound and MRI for determination of extent of DVT into pelvic veins, with MRI showing consistently more detailed depiction of extension. Our results indicate that MRI has an important role as a complementary technique in the diagnosis of DVT during pregnancy.

The importance of rectal cancer MRI protocols on iInterpretation accuracy

BackgroundMagnetic resonance imaging (MRI) is used for preoperative local staging in patients with rectal cancer. Our aim was to retrospectively study the effects of the imaging protocol on the staging accuracy.Patients and methodsMR-examinations of 37 patients with locally advanced disease were divided into two groups; compliant and noncompliant, based on the imaging protocol, without knowledge of the histopathological results. A compliant rectal cancer imaging protocol was defined as including T2-weighted imaging in the sagittal and axial planes with supplementary coronal in low rectal tumors, alongside a high-resolution plane perpendicular to the rectum at the level of the primary tumor. Protocols not complying with these criteria were defined as noncompliant. Histopathological results were used as gold standard.ResultsCompliant rectal imaging protocols showed significantly better correlation with histopathological results regarding assessment of anterior organ involvement (sensitivity and specificity rates in compliant group were 86% and 94%, respectively vs. 50% and 33% in the noncompliant group). Compliant imaging protocols also used statistically significantly smaller voxel sizes and fewer number of MR sequences than the noncompliant protocolsConclusionAppropriate MR imaging protocols enable more accurate local staging of locally advanced rectal tumors with less number of sequences and without intravenous gadolinium contrast agents.

The minimum number of target lesions that need to be measured to be representative of the total number of target lesions (according to RECIST)

Response evaluation criteria in solid tumours (RECIST) were introduced as a means to classify tumour response with no definition of the minimum number of lesions. This study was conducted in order to evaluate discrepancies between full assessments based on either all target lesions or fewer lesions. RECIST evaluation was performed on separate occasions based on between one and seven of the target lesions, with simultaneous assessment of non-target lesions. 99 patients were included. 38 patients demonstrated progressive disease, in 61% of whom it was a result of the appearance of new lesions or unequivocal progress in non-target lesions. 32 patients showed stable disease, with 8 having results that differed when 1-3 target lesions were measured. 22 cases were considered as having partial regression, with only 1 case differing when performing 1-3 target lesion assessments. Seven cases demonstrated complete response. The number of discordant cases increased gradually from measuring three lesions to one target lesion. The average number of available target lesions among those with discrepancies was 7.1, which was significantly higher than those demonstrating concordance (4.1 lesions; p<0.05). In conclusion, measuring fewer than four target lesions might cause discrepancies when more than five target lesions are present.

Manifestations of small bowel disease in pediatric Crohn's disease on magnetic resonance enterography

Background: We report the manifestations of Crohns disease (CD) observed on magnetic resonance enterography (MRE) in a pediatric population at the time of CD diagnosis. Methods: MRE of 95 consecutive pediatric patients with inflammatory bowel disease (IBD) examined in 2006–2009 were retrospectively analyzed, with documentation of findings based on type and location of the small bowel (SB) disease. Results: In all, 51 were boys and 44 girls. 54 had CD, 31 non‐CD IBD, and 10 no IBD. The most common site of SB involvement in CD was the terminal ileum seen in 29 (53.7%) patients, followed by ileum in 10 (18.5%) and jejunum in 9 (16.7%) patients. Solitary jejunal inflammation (3.7%), SB stenoses (1.9%), fistula formation (0.95%), and abscess (0.95%) were much less common. Perienteric lymphadenopathy was seen in 30 (55.6%) patients and fatty proliferation in 9 (16.7%). The most common manifestation of SB inflammation was increased contrast enhancement of bowel wall (93.5%), thickening of the bowel wall (90.3%), and derangement of bowel shape with saccular formations (25.8%). Conclusions: MRE in the pediatric population often demonstrates increased contrast uptake, bowel wall thickening, and perienteral lymphadenopathy in CD. More chronic small bowel changes seen commonly in adults and solitary jejunal involvements are less commonly seen. (Inflamm Bowel Dis 2012;)

Morphological assessment of the interface between tumor and neighboring tissues, by magnetic resonance imaging, before and after radiotherapy in patients with locally advanced rectal cancer

Background: Magnetic resonance imaging (MRI) in rectal cancer is sometimes performed after radiotherapy (MRI 2) to evaluate tumor response and to choose alternative forms of surgery. The accuracy of MRI 2 in distinguishing tumor delineation might be difficult due to fibrosis. Purpose: To evaluate the morphological changes in the interface between the tumor and neighboring organs on MRI 2 performed after radiotherapy, and to assess the accuracies of MRI before and after radiotherapy compared to histopathology after surgery. Material and Methods: Sixteen patients with locally advanced primary rectal cancer, with MRI before and after radiotherapy, were retrospectively studied, concerning the interface between the tumor and neighboring structures. The accuracies of MRI before and after radiotherapy were compared based on histopathology as a reference. Results: The accuracies of both MRI before and after radiotherapy were moderate, with no additional value of MRI after radiotherapy compared to MRI before radiotherapy. The most predictive form of interface for involvement of a neighboring organ after radiotherapy was nodular growth of the tumor into a neighboring structure. Conclusion: The morphological assessment of pelvic MRI after preoperative radiotherapy does not provide any significant new information about tumor extent in patients with locally advanced rectal cancer.

Enterclysis versus enterography: the unsettled issue

Sir, As radiologists interested in abdominal imaging with MRI, we read the interesting work by Masselli et al. [1] in the March issue of European Radiology. We have been using MR enterography (MREg) for quite some time and we have felt that we have had no need to use MR enteroclysis (MREc) in patients with Crohn’s disease. Reading the article by Masselli and co-workers, therefore, was very fascinating. In their work, they found a significant difference between the accuracy of MREc and MREg in finding mucosal lesions compared with conventional enteroclysis (CE), which served as the ‘gold standard’. There remain, however, some unanswered questions. Statistical questions: The authors have made two sets of comparisons, one directly between MREc and MREg, and the other indirectly by comparing them with CE. When comparing MREc and MREg directly, one has to either preferably choose the same population, or at least ensure that the two populations are not statistically different. The authors have randomized their data, with most but not all patients accepting such randomization. We would like to know if the authors did look at any possible statistical differences between the two populations regarding CE findings. This is particularly important in lieu of the small figures of the study and that parameters such as sensitivity and specificity are dependant on the prevalence of diseases. The authors also compare the two methods indirectly. One should be cautious in the interpretation of these results. Non-significant statistical difference does not mean that the two methods perform equally well. The most common cause of this probable type of error (type II) is lack of statistical power. It is quite probable that MREc is also inadequate in diagnosing all mucosal lesions [2], yet the low power of the study (22 total patients) does not reveal the expected difference. MRI technique and interpretation: The authors have not used all the possible adjustments that could improve imaging quality in MREg, such as cine imaging or additional rectal enema [3–5]. In addition, we have come to rely heavily on bowel wall enhancement, which is especially true in CTenterography [6]. Bowel wall enhancement is not depicted on CE, yet it helps greatly in image interpretation [7]. Mucosal lesions and their importance: There are two main reasons why we perform mainly MREg for our patients with Crohn’s disease instead of MREc. One is that we do not believe that performing MREc can help us exclude minor manifestations of the disease anyway [8], and the other is that the significance of these lesions is unclear to us. Most patients with superficial manifestations have other signs of the disease somewhere else in the bowel [9]. For instance, the authors have made it clear that the majority of lesions missed had only signs in A reply on this paper is available at doi:10.1007/s00330-008-1136-1.

The accuracy of focused abdominal CT in patients presenting to the emergency department.

Focused computed tomography(CT) examination (FCT) is CT limited to a specific abdominal area in an attempt to reduce radiation exposure. We wanted to evaluate FCT on the basis of information from the request form and thus reduce radiation dose to the patient without missing relevant findings. We retrospectively analyzed 189 consecutive acute abdominal CT, dividing the findings as localized in the upper or lower abdomen. Another researcher blindly determined where the CT should be focused to, based only on information provided in the request form. The sensitivity and specificity of FCT in patients with symptoms from only upper abdomen was 100%. Sensitivity, specificity, and accuracy of FCT in patients with symptom from only lower abdomen were 79%, 100%, and 92%, respectively. Our study suggests that among patients with symptoms from the lower abdomen, not examining the upper abdomen would lead to missing relevant findings.