Endorectal coil MRI in local staging of rectal cancer

PURPOSE: The choice of the therapeutic strategies in patients affected with rectal cancer is strictly dependent by the tumor stage. So, in order to obtain an improvement in preoperative staging accuracy, new imaging modalities are now under investigation. The aim of this work is the evaluation of endorectal-coil MRI in the local staging of rectal cancer. MATERIAL AND METHODS: Fourty-three patients affected with histologically proven rectal cancer, have been evaluated by an high-field strength magnet (1.5 T). In 14/43 patients neoadjuvant pre-operative chemotherapy had been previously performed. In all cases axial SE T1w and FSE T2w sequences and coronal or sagittal FSE T2w sequences, with and without fat suppression, were performed. Basing upon the TNM staging system and the previously reported MRI signs the local extent of the tumor was evaluated, focusing about the rectal wall infiltration and the perirectal lymph nodes involvement. All the patients underwent surgery and a comparative evaluation of MRI and pathological staging was done. RESULTS: At MRI the tumor was detected in 38/43 patients. In evaluating wall infiltration the MRI results agreed with pathological results in 89% of patients and showed 92% accuracy in T1-T2 stage and 94% in T3. In evaluating perirectal lymph nodes metastases MRI showed 69% accuracy, 82% sensitivity and 55%specificity. DISCUSSION AND CONCLUSIONS: The poor accuracy of CT and body-coil MRI in evaluating wall involvement in patients with rectal cancer is mainly related to their inability to demonstrate the single layers of the rectal wall. So transrectal ultrasound is now the first choice modalitiy in local staging of rectal cancer. However transrectal ultrasound showed low sensitivity in detecting perirectal lymph nodes metastases and low accuracy in evaluating the patients previously undergone to neoadjuvant chemotherapy or radiotherapy. On the other hand the improvement of MRI sequences and the availability of the endorectal coils allowed to visualize the single layers of the rectal wall so making the endorectal-coil MRI a reliable imaging technique to stage rectal cancer. The results of our work demonstrate a good diagnostic accuracy of endorectal-coil MRI in local staging of rectal cancer, in particular the degree of rectal wall infiltration was well demonstrated, while the perirectal lymph nodes metastases were demonstrated with less accuracy. The long examination time, the costs and the movement-related artefacts are the main limits of MRI. In particular the movement-related artifacts sometime do not allow the visualization of the wall layers so lowering the diagnostic accuracy in demonstrating the tumor wall infiltration. In conclusion, even though endorectal coil MRI proved to be a reliable imaging technique in local staging of rectal cancer, at present we are not able to state what may be its real role in diagnostic evaluation of the patients with rectal cancer, in particular if compared to endorectal ultrasound. Further, comparative studies, based upon larger patients series are probably needed to draw a definitive conclusion.     

Duplex sonography in the evaluation of carotid artery disease

High-resolution duplex sonography was compared with biplane magnified carotid angiography in a prospective evaluation of 161 carotid arteries in 86 patients. The duplex scanner combined real-time B-mode imaging (7.5 MHz) with simultaneous range-gated pulsed Doppler frequency analysis (3 MHz). The degree of stenosis was usually determined by the true and residual lumen of the carotid artery at the atherosclerotic plaque on the transverse image. The Doppler frequency signals were automatically converted to velocity data by a minicomputer. The accuracy of the duplex system in detecting and assessing stenoses graded in 20% increments is demonstrated according to specificity, sensitivity, and positive and negative predictive value by both cumulative and subgroup analyses. A 93.7% sensitivity was shown for minimal (0-20%) stenosis and 100% sensitivity for severe (greater than 60%) stenosis. An apparent limitation of duplex sonography is the differentiation of a high-grade stenosis from occlusion (sensitivity, 82.6%; positive predictive value, 90.4%).     

Endorectal magnetic resonance imaging of a rectal duplication cyst

A case of a duplication cyst of the rectum is presented. This case highlights the potential role of endoluminal magnetic resonance imaging in the diagnosis of this uncommon condition. Alternative imaging modalities and differential diagnoses are discussed.     

Computed tomographic evaluation of thickness of perirectal fascia in rectal cancer treated by preoperative radiotherapy--diagnostic value for prediction of local recurrence

Perirectal fascia was examined by computed tomography before and after preoperative radiotherapy in thirty-six patients with rectal cancer. CT measurement showed that perirectal fascia tend to increase in thickness during preoperative radiotherapy in proportion to tumor extension into perirectal fat tissue. The fascial thickening more than 7 mm after preoperative radiotherapy was suggestive of local recurrence to develop. Preoperative or intraoperative boost irradiation would be recommended for such high-risk patients.     

Dynamic sonography in the evaluation of jaundice

The value of dynamic sonography as a screening procedure in 84 jaundiced patients was examined and compared with the clinical evaluation of a blind prospective study. The predictive value of the sonographic diagnosis of obstruction was 97% and 84% in nonobstruction. The corresponding values of the clinical distinction were 87% and 92% respectively. The level of obstruction was demonstrated in 95% and the cause of obstruction was diagnosed in 68%. When the cause of jaundice is uncertain or obstruction is suspected clinically, dynamic sonography can offer high diagnostic accuracy and guidance for invasive investigations.     

Crohn disease: perirectal and perianal findings at CT

The computed tomographic scans of 200 consecutive patients with Crohn disease were studied to determine the frequency and patterns of perirectal and perianal involvement. In 163 patients (82%) abnormalities in the perirectal-perianal region were demonstrated; findings included inflammation of fat planes (73%), bowel wall thickening (30%), fistulas or sinus tracts (22%), and abscesses (14%). Fistulas or sinus tracts occurred with equal frequency above or below the level of the anterior symphysis pubis. Abscesses, rectal thickening, and inflammatory infiltration of fat occurred more than twice as often above the symphysis pubis. However, 37% of patients had manifestations of Crohn disease below the symphysis pubis, emphasizing the importance of extending scanning sequences to the perineum.     

Transrectal sonography in prostate evaluation

Prostate cancer is the most prevalent newly diagnosed noncutaneous malignancy in men. With the continued use of prostate-specific antigen screening, there has been a dramatic rise in the number of prostate biopsied performed. Transrectal ultrasonography (TRUS) is an essential tool used for detecting prostate pathology and performing prostate biopsies. This article review the indications and principles of TRUS of the prostate, the technique of TRUS, and controversies pertaining to prostate core biopsy.     

Quantitative assessment of perirectal tumor infiltration with dynamic contrast-enhanced multi-detector row CT in rectal cancer

Objective

To evaluate the efficacy of discriminant function analysis of perirectal tumor infiltration with dynamic contrast-enhanced 64-detector row CT in rectal cancer.

Materials and methods

Forty-nine patients with rectal cancer underwent dynamic contrast-enhanced CT. A total of 96 axial CT slices containing the tumors were evaluated. The 96 images were separated into two groups with or without perirectal tumor infiltration based on pathological findings. The discriminant function was set-up using CT density differences between the mass and the adjacent perirectal tissue within 5 mm from the mass at 20 and 40 s as independent variables. The results of the discriminant function analysis were compared to those of CT morphology and pathology.

Results

CT morphological diagnosis was accurate on 71.9% (69/96) of the slices with 82.5% sensitivity and 64.3% specificity. Discriminant function analysis correctly identified 88.5% (85/96) of the slices with 85.0% sensitivity and 91.1% specificity. Overstaging occurred significantly more (P < 0.05) on morphological analysis (20.8%, 20/96) than discriminant function analysis (5.2%, 5/96) of the CT slices.

Conclusions

Discriminant function analysis of dynamic contrast-enhanced CT improves the diagnostic accuracy and specificity of perirectal tumor infiltration in rectal cancer.     

The value of transrectal sonography in assessing radiogenic rectal changes

The clinical value of TRS in diagnosis and staging of radiogenic rectal disorders is discussed. TRS was performed on 120 patients with tumours of lower pelvis who were treated by radiotherapy. They were divided in this trial into 2 groups. Group I (n = 113, with a mean interval to radiotherapy of 2 years) including patients who were under a routine control. Group II (n = 7, with a mean interval to radiotherapy of 13 years) including patients with strong local pain of the radiotherapy zone. The sonographic changes were divided into 4 grades (0-III) and verified histologically in group II patients by means of biopsy. A control group (n = 35) was also examined by TRS. The patients of this group were not treated radiotherapeutically. We concluded in our study that TRS in radiogenic rectal disorders, give us a very precise grading of the tumours which in turn, is of great importance in the further therapeutic procedure and in the evaluation of tumour recidives and second malignomas of the rectal wall.     

Transrectal sonography of anal sphincter infiltration in lower rectal carcinoma

OBJECTIVE: The purpose of the study was to assess the accuracy of transrectal sonography in determining invasion by lower rectal cancer into the anal canal. SUBJECTS AND METHODS: Thirty-eight patients (14 women, 24 men; mean age, 65 years) with lower rectal cancer underwent transrectal sonography before surgery. Both depth of infiltration and tumor invasion into the anal canal were assessed, and results were compared with histopathology of the resected specimens. RESULTS: Infiltration into the anal canal was found histopathologically in 12 (32%) of 38 patients. Transrectal sonography revealed a true-positive diagnosis in 11 of these 12 patients. A false-positive diagnosis of anal canal infiltration was made in two patients for a sensitivity of 91%, a specificity of 85%, and an accuracy of 92%. In the 11 patients diagnosed correctly on transrectal sonography, the depth of tumor infiltration into the anal canal corresponded with histopathology. CONCLUSION: This study shows that transrectal sonography is an accurate method for assessment of anal canal infiltration in lower rectal cancer.     

Doppler sonography: a noninvasive method for evaluation of hepatic venocclusive disease

Hepatic venocclusive disease is a serious complication associated with chemotherapy and radiation used in bone marrow transplantation patients. In the past, liver biopsy has been the only reliable means of diagnosing venocclusive disease. Biopsy in such patients may be dangerous or impossible because of severe coagulopathies. The purpose of our study was to evaluate duplex Doppler sonography in diagnosing hepatic venocclusive disease. We measured the blood velocity and flow in the portal vein, hepatic vein, and inferior vena cava of six patients who were histologically proved to have developed hepatic venocclusive disease after bone marrow transplantation. There were three men and three women with a mean age of 32 years (range, 21-44 years). Examination with Doppler sonography suggested the diagnosis a mean of 41 days (range, 11-62 days) after transplantation. In three patients, the diagnosis was suggested by reversed or "to and fro" flow in the portal vein. In the other three patients, the diagnosis was suggested by a decreased flow in the portal vein. One of these patients with decreased flow had subclinical hepatic venocclusive disease. In this patient, it was not the absolute level of flow but the decrease from a baseline established before ablative therapy that suggested the diagnosis. The amplitude of pulsatility in the hepatic veins appeared to decrease with the onset of venocclusive disease. In the hepatic veins and inferior vena cava, flow toward the heart was maintained. Our findings suggest that duplex Doppler sonography may be useful in detection of hepatic venocclusive disease. We speculate that, with wider experience, Doppler sonographic detection of decreased or reversed flow in the portal vein, in the proper clinical setting, may provide a noninvasive means of reliably diagnosing hepatic venocclusive disease in patients too ill to undergo liver biopsy.     

Scrotal sonography in acute disease

Ultrasound is the appropriate first diagnostic imaging study in the evaluation of acute scrotal disease. This review highlights the major causes of acute disease of the scrotal sac, testis, epididymis, and spermatic cord, details the typical findings of the pathologic entities, and defines how duplex and color Doppler improve the diagnostic yield.     

Endorectal MR imaging in the evaluation of seminal vesicle invasion: diagnostic accuracy and multivariate feature analysis

PURPOSE: To retrospectively determine the accuracy of endorectal magnetic resonance (MR) imaging in demonstrating seminal vesicle invasion (SVI) and to investigate the MR imaging features that can predict SVI. MATERIALS AND METHODS: The Institutional Review Board granted exempt status for this retrospective study, with waiver of informed consent; patient data were collected and handled in accordance with HIPAA regulations. Fifty-one men (age range, 44-73 years) with SVI and 303 men (age range, 40-76 years) without SVI who underwent endorectal MR imaging before radical prostatectomy between January 2000 and October 2004 were included in the study. Endorectal MR images were retrospectively and independently analyzed by two radiologists for SVI, tumor at prostate base, extracapsular extension, and other features considered indicative of SVI. Areas under the receiver operating characteristic curves (AUCs) were used to assess the accuracy of detecting SVI at endorectal MR imaging. A multiple logistic regression was used to explore the combinations of MR imaging features that might facilitate the detection of SVI. RESULTS: Readers 1 and 2 had an AUC of 0.93 and 0.81, respectively, for the detection of SVI. For both readers, the features that had the highest sensitivity and specificity were low signal intensity within the seminal vesicle and lack of preservation of seminal vesicle architecture. At multiple regression analysis, tumor at the prostate base that extended beyond the capsule and low signal intensity within a seminal vesicle that has lost its normal architecture were highly predictive of SVI. CONCLUSION: Endorectal MR imaging is accurate in demonstrating SVI prior to radical prostatectomy, and recognition of the most predictive features may facilitate the use of this modality.     

Late sequelae of percutaneous nephrolithotomy: evaluation by high-resolution sonography and colour-coded sonography

We examined 50 asymptomatic patients 6–60 months after percutaneous nephrolithotomy (PCNL) by high-resolution sonography and additional colour-coded sonography and compared our results with the preoperative sonograms and the operative records. No lesions of larger vessels were detected, either arteriovenous fistulate or pseudoaneurysms. Avascular band-shaped hyperechoic parenchymal stripes were found in 17 of 50 patients (35%). As these did not appear in the preoperative sonograms, and as the stripes were in the same orientation as the neprrostomy canal, we believe them to be scar tissue. Correspondence to: R. Knapp