| 21. |
- Torkzad, Michael R., et al.
(författare)
-
Magnetic resonance imaging (MRI) in rectal cancer : a comprehensive review
- 2010
-
Ingår i: Insights into Imaging. - : Springer Science and Business Media LLC. - 1869-4101. ; 1:4, s. 245-267
-
Tidskriftsartikel (refereegranskat)abstract
- Magnetic resonance imaging (MRI) has established itself as the primary method for local staging in patients with rectal cancer. This is due to several factors, most importantly because of the ability to assess the status of circumferential resection margin. There are several newer developments being introduced continuously, such as diffusion-weighted imaging and imaging with 3 T. Assessment of loco-regional lymph nodes has also been investigated extensively using different approaches, but more work needs to be done. Finally, evaluation of tumours during or after preoperative treatment is becoming an everyday reality. All these new aspects prompt a review of the most recent advances and opinions. In this review, a comprehensive overview of the current status of MRI in the loco-regional assessment and management of rectal cancer is presented. The findings on MRI and their accuracy are reviewed based on the most up-to-date evidence. Optimisation of MRI acquisition and relevant regional anatomy are also presented, based on published literature and our own experience.
|
|
| 22. |
- Torkzad, Michael R., et al.
(författare)
-
Magnetic Resonance Imaging of Rectal and Anal Cancer
- 2014
-
Ingår i: Magnetic Resonance Imaging Clinics of North America. - : Elsevier BV. - 1064-9689. ; 22:1, s. 85-
-
Tidskriftsartikel (refereegranskat)abstract
- Magnetic resonance imaging plays a pivotal role in the imaging and staging of rectal and anal carcinomas. Rectal adenocarcinomas and anal squamous cell carcinomas behave differently, and are staged and treated differently. This article attempts to explain these 2 entities, which share the same regions of interest, in a comprehensive manner.
|
|
| 23. |
- Torkzad, Michael R
(författare)
-
Magnetic resonance imaging of rectum : diagnostic and therapy related aspects
- 2006
-
Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Papers I-II: The purpose of paper 1 was to assess the size and configuration of the perirectal fatty tissues (PF) using magnetic resonance imaging (MRI). In 25 subjects the volume and cross-sectional parameters based on the amount of PF to different sides of die rectum, and the total area occupied were retrospectively measured on MRI. There was a good correlation between anteroposterior diameter of the PF at four centimeter below S 1-2 (and the left-to-right diameter seven centimeter below S 1-2), and mesorectal volume (NW). Furthermore, the form of PF differed significantly between male and female subjects. In paper II, we analyzed the influence of MV on the accuracy of the first preoperative MRI. 267 patients with rectal cancer had their MV measured without knowledge of the prospective evaluations by the radiologist or the pathologist, and the discrepancies in the results were correlated to the MV and clinical data. T- or N-staging accuracy by MRI did not significantly correlate to MV. The difference between assessment by radiologist and pathologist did not differ based on MV. Finally patients with larger MV did not have fewer cases with involvement of mesorectal fascia (MF) or involvement of neighboring organs. Thus, MV does not appear to affect the locoregional prognostic factors, nor is it able to explain the difference in evaluation between the radiologist and pathologist. Papers III-IV: In paper III we tried to find out if the tumor size on MRI in patients without preoperative radiotherapy correlates to the corresponding pathologic findings. 18 patients were included. The tumor size was measured on MR and histopathologic specimen. Regression curves showed best correlations for area (r2=0.75) and volume (r2=0.65-0.82). With the formula proposed from this material, we assume that rectal tumors can be measured on MR images using a metric model, and then extrapolated to what we would expect from pathology, hence providing us with a tool where we could measure tumor response after neoadjuvant therapy. In paper IV, we used these tools to evaluate changes after radiotherapy and correlation between MRI and histopathology. RVs was defined as the residual pathologic tumor volume while RVm was similarly defined as the residual MRI tumor volume at 2 nd MRI. 25 patients with MRI before and after radiotherapy were included. The second MRI was not more accurate than the initial MRI for assessment of the T-stage or distance to circumferential resection margin (CRM). RVm showed significant correlation to RVs and pathologic T-stage. A 2 nd MRI alone after radiotherapy with delay before surgery has limited value in understanding the individual response to therapy, but followup volumetry can be helpful to understand which tumors have responded. Paper V: The aim of this study was to determine the sites of local recurrence (LR) following radical total mesorectal excision (TME) for rectal cancer in an effort to elucidate the reasons for recurrence. 33 CT and MRI of 37 patients with LR were examined. 29 LR were found in the lower two-thirds of the pelvis, with two appearing to originate from lateral pelvic lymph nodes (LN). Evidence of residual PF was identified in 15 patients. 14 of the LR originated from primary tumors in the upper rectum and 12 of them with evidence of residual PF. Lateral pelvic LN metastases are not a major cause of LR after TME. Partial mesorectal excision may be associated with an increased risk of LR from tumors in the upper rectum.
|
|
| 24. |
- Torkzad, Michael R, et al.
(författare)
-
Manifestations of small bowel disease in pediatric Crohn's disease on magnetic resonance enterography
- 2012
-
Ingår i: Inflammatory Bowel Diseases. - : Oxford University Press (OUP). - 1078-0998 .- 1536-4844. ; 18:3, s. 520-528
-
Tidskriftsartikel (refereegranskat)abstract
- BACKGROUND: We report the manifestations of Crohn's 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.
|
|
| 25. |
- Torkzad, Michael R., 1968-, et al.
(författare)
-
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
- 2008
-
Ingår i: Acta radiologica (Stockholm, Sweden : 1987). - : SAGE Publications. - 1600-0455 .- 0284-1851. ; 49:10, s. 1099-103
-
Tidskriftsartikel (refereegranskat)abstract
- 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.
|
|
| 26. |
- Torkzad, Michael R., et al.
(författare)
-
MRI after preoperative radiotherapy for rectal cancer; correlation with histopathology and the role of volumetry.
- 2007
-
Ingår i: European Radiology. - : Springer Science and Business Media LLC. - 0938-7994 .- 1432-1084. ; 17:6, s. 1566-1573
-
Tidskriftsartikel (refereegranskat)abstract
- The objective is to assess if tumor size after radiotherapy in patients with rectal cancer can be assessed by a second magnetic resonance imaging (MRI), after radiotherapy prior to surgery and to correlate changes observed on MRI with findings at histopathology at surgery. Twenty-five patients with MRI before and after radiotherapy were included. Variables studied were changes in tumor size, T-staging and distance to the circumferential resection margin (CRM). RVs was measured as tumor volume at surgery (Vs) divided by tumor volume at the initial MRI (Vi) in percent. RVm was defined as the tumor volume at the second MRI (Vm) divided by Vi in percent. The ypT-stage was the same or more favorable than the initial MRI T-stage in 24 of 25 patients. The second MRI was not more accurately predictive than the initial MRI for ypT-staging or distance to CRM (p > 0.05). Vm correlated significantly to Vs, as did RVs to RVm, although the former was always smaller than the latter. Vm and RVm correlated well with ypT-stage (p < 0.001). Volumetry seems to correlate with ypT-stage after preoperative radiotherapy for resectable rectal cancer. The value of a second MRI after radiotherapy for assessment of distance to CRM and ypT-staging is, however, not apparent.
|
|
| 27. |
- Torkzad, Michael R., et al.
(författare)
-
MRI for assessment of anal fistula
- 2010
-
Ingår i: Insights into Imaging. - : Springer Science and Business Media LLC. - 1869-4101. ; 1:2, s. 62-71
-
Tidskriftsartikel (refereegranskat)abstract
- Magnetic resonance imaging (MRI) is the best imaging modality for preoperative assessment of patients with anal fistula. MRI helps to accurately demonstrate disease extension and predict prognosis. This in turn helps make therapy decisions and monitor therapy. The pertinent anatomy, fistula classification and MRI findings will be discussed.
|
|
| 28. |
- Torkzad, Michael R.
(författare)
-
Nyheter inom lever-MRT
- 2011
-
Annan publikation (övrigt vetenskapligt/konstnärligt)
|
|
| 29. |
- Torkzad, Michael R., et al.
(författare)
-
Significance of mesorectal volume in staging of rectal cancer with magnetic resonance imaging and the assessment of involvement of the mesorectal fascia
- 2007
-
Ingår i: European Radiology. - : Springer Science and Business Media LLC. - 0938-7994 .- 1432-1084. ; 17:7, s. 1694-1699
-
Tidskriftsartikel (refereegranskat)abstract
- The aim was to study the influence of mesorectal volume, as estimated by magnetic resonance imaging (MRI), that is to be removed during total mesorectal excision (TME), on the accuracy of the first preoperative MRI of rectal cancer compared to histopathology, and its correlation to locoregional prognostic factors. A total of 267 rectal cancer patients from a multinational study (MERCURY or MRI equivalence study) had their mesorectal volume retrospectively estimated by researchers without knowledge of the assessments made by the radiologist or the pathologist. The evaluations made by the pathologist and the radiologist were then compared, including T- and N-staging, assessment of extent of extramural tumor invasion (the largest portion of the tumor beyond the muscularis propria or EMI) and distance to mesorectal fascia; the discrepancies in the results were correlated to the mesorectal volume. T- or N-staging accuracy by MRI and the difference between the EMI as measured by the pathologist and the radiologist were not dependent on individual mesorectal volume. There was no correlation between assessment of involvement of mesorectal fascia or local neighboring organs by MRI and histopathology with mesorectal volume. Mesorectal volume does not affect locoregional prognostic factors or the accuracy of local staging of rectal cancer.
|
|
| 30. |
- Torkzad, Michael R., et al.
(författare)
-
Stereology : a novel technique for rapid assessment of liver volume
- 2012
-
Ingår i: Insights into Imaging. - : Springer Science and Business Media LLC. - 1869-4101. ; 3:4, s. 387-393
-
Tidskriftsartikel (refereegranskat)abstract
- BACKGROUND:The purpose of this study was to test the stereology method using several grid sizes for measuring liver volume and to find which grid provides an accurate estimate of liver volume.MATERIALS AND METHODS:Liver volume was measured by volumetry in 41 sets of liver MRI. MRI was performed before and after different weight-reducing regimens. Grids of 3, 4, 5, and 6 cm were used to measure liver volume on different occasions by stereology. The liver volume and the changes in volume before and after treatment were compared between stereology and volumetry.RESULTS:There was no significant difference in measurements between stereology methods and volumetry (p > 0.05). The mean differences in liver volume between stereology based on 3-, 4-, 5-, and 6-cm grids and volumetry were 37, 3, 132, and 23 mL, respectively, and the differences in measurement of liver volume change were 21, 2, 19, and 76 mL, respectively. The mean time required for measurement by stereology was 59-190 s.CONCLUSION:Stereology employing 3- and 4-cm grids can rapidly provide accurate results for measuring liver volume and changes in liver volume.MAIN MESSAGES:• Statistical methods can be used for measuring area/volume in radiology.• Measuring liver volume by stereology by 4-cm grids can be done in less than two minutes.• Follow-up of liver volume is highly accurate with stereological methods.
|
|
