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The ultrasonic diagnosis of urachal anomalies
292
CLINICAL IMAGING VOL. 20, NO. 4
ABSTRACTS
sequences. To investigate the potentials of FAT-SAT sequences in MR imaging of the upper abdomen, the authors carried out a prospective study including 129 subjects, namely 12 normal volunteers and 117 patients with different abdominal conditions. The patients were submitted to Tl-weighted SE sequences (TR 500-600 ms, TE 15 ms), T2W SE (TR1600-1730 ms, TE 80 ms), and PD SE (TR 1600-1730 ms, TE 20 ms). The images obtained with and without fat suppression were compared both qualitatively and quantitatively, with a special emphasis on the normal anatomy of the upper abdomen: we investigated the efficacy of subcutaneous and retroperitoneal fat suppression (116/129 cases, 90%), the reduction in respiratory and chemical shift artifacts (112/129 cases, 87%), and the better visualization of parenchyma (119/129 cases, 93%) and of other abdominal structures. Concerning the quantitative study, we calculated the signal-to-noise ratio (S/N) for liver, spleen, pancreas, adrenal glands, renal cortex, and medulla, the improvement of contrast in these organs after retroperitoneal fat suppression (conspicuity), and the increase in contrast between organs (dynamic range). The statistical analysis showed significant differences between the sequences with and those without fat suppression. Correlations were found between observers’ and quantitative evaluations, suggesting that the better yield of FAT-SAT sequences is probably due to three factors: (1) retroperitoneal and subcutaneous fat suppression: (2) increase in S/Nratio for pancreas and renal cortex on TlW images; (3) reduction in the dynamic range of signal intensity, which increases contrast between pancreas, adrenal glands, and renal cortex relative to adjacent structures, especially on T2W or PD sequences. The results of this study suggest that FAT-SAT sequences are useful because fat suppression increases contrast and improves image quality, reducing respiratory and chemical shift artifacts. Authors’
Summary
MRI EVALUATION OF ANO-PERINEAL FISTULAE: DIAGNOSTIC CONTRIBUTION OF T2 WEIGHTED SEQUENCES (In French) Tissot 0, Bodnar D, Henry L, et al. (Service Central de Radiologie, Centre Hospitalier GBnBral, F-44606 Saint-Nazaire Cedex, France). J Radio1 1996;77:255-260.
The role of magnetic resonance imaging (MRI) in the evaluation of anal fistulae is well recognized. In this article the authors report the data obtained by a detailed evaluation of these lesions as detected by MRI, SE TZweighted sequences. Eighteen consecutive patients with anal fistula were examined by MRI before surgery. A cryptogenetic fistula was present in 12 patients: an anoperineal fistula was related to Crohn’s disease in 4; and, in one case each, the fistula was secondary to an ulcerative hemorrhagic rectocolitis or to a pilonidal cyst. The examinations were conducted at 0.5 T. In the first two cases in Tl- and T2weighted sequences and in the remaining 16 patients only TZweighted sequences were obtained in 25 sections of 5 mm in the coronal and axial planes. Prior to the examination a balloon in the anal canal was inflated with 60 ml of air. A review of the MR images obtained showed that productive lesions (16 patients) were hyperintense in the T2 sequences, while the fistulae, which did not contain fluid, and those surrounded by cicatricial tissue were iso- or minimally hyperintense. Fissures involving the anal wall in Crohn’s disease appeared as linear hyperintense signals. If the lesion involved the supra-elevator space two images were detected, either intramural fistulous tracts extending from the anal canal with hyperintense signals or as nodular pararectal signals related to abscess formations. In 11 patients it was possible to visualize the internal orifice of the fistula when the signal became hyperintense in reaching the anal canal. Healed fistulae could not be demonstrated. The fistulae were distinguished, according to the classification proposed by Park, Gordon, and Hardcastle (Brit J Surg 1976;63:1-12), in intersphincteric (4/18), transphincteric (2/18), suprasphincteric (10/18), and extrasphincteric (l/18). The last case, an abscess involving a pilonidal cyst, did not extend to the sphincter. At surgery, the fistulous tract was simple in 8 patients and complex in 10, confirming in 4 patients the presence of an abscess in the true supralevator space. In the opinion of the authors MRI of the anal canal with SE T2-weighted sequences, in the two axial planes, is sufficient in the demonstration and characterization of anal fistulae. Numerous and clear figures illustrate the article. Antonio
F. Govoni, MD
THE ULTRASONIC DIAGNOSIS OF URACHAL ANOMALIES Holten I, Lomas F, Mouratidis B, et al. (F.L.: Woden Valley Hospital, Garran, ACT
OCTOBER-DECEMBER I996
2605, Australia). 1996:40:2-5.
Austral Radio1
Between 1982 and 1994 seven patients ranging in age between 20 months and 28 years were operated on for urachal anomalies. All patients were studied before surgery by ultrasonography (US). The procedure correctly diagnosed the pathological process in six patients. An umbilical sinus presenting with bleeding and serous discharge was not recognized. An urachal anomaly was detected in a 28-year-old pregnant woman prior to semi-elective cesarean section. The sonographic images of a fixed, midline, and predominately cystic swelling, located between the umbilicus and the bladder, and its extraperitoneal location and resistance to movements would distinguish such an anomaly from other abdominal cysts and suggest the diagnosis of a urachal anomaly. Antonio
F. Govoni,
MD
MAGNETIC RESONANCE IMAGING OF THE KIDNEY: EVALUATION OF NEW PULSE SEQUENCES AND COMPARISON WITH COMPUTED TOMOGRAPHY IN THE DIFFERENTIAL DIAGNOSIS OF SPACE OCCUPYING LESIONS (In German) Kreft B, Steudel A, Textor J, et al. (Radiologische Klinik der Universitgt Bonn, Sigmund-Freud-Str. 25, D-53127, Germany). Fortschr Riintgenstr 1996;164:212-217. The purpose of this study was to evaluate new pulse sequences (turbo-spin-echo [TSE] and turbo-fieldecho [TFE] sequences) for study protocol optimization and to assess the role of magnetic resonance imaging (MRI) in the differential diagnosis of renal tumors. In six volunteers MRI of the kidney was performed at 0.5 T using a conventional T,-weighted spin-echo (SE) sequence (T,lr, 1800/90 ms) and three different TSE sequences (TR 1800-5000 ms, Tt 90-150 ms). Additionally, computed tomography (CT) and MRI were performed in 34 patients with 41 renal masses. Two readers evaluated both images regarding the differentiation between malignant and benign masses. The pilot study showed that the heavily T,-weighted TSE sequence (TRITE 5500/150 ms) was superior to other sequences with regard to image quality and differentiation of the corticomedullary junction. In the clinical study malignant tumors were correctly classified with CT and MRI in
ABSTRACTS
293
86.4 and 95.5% of the cases, whereas the accuracy in the diagnosis of benign lesions of CT and MRI was 73.7 and 89.5%, respectively. The results obtained indicated that using new pulse sequences MRI is superior to CT in the differential diagnosis of renal tumors in the differentiation between complicated cysts and cystic or hypovascular renal cell carcinomas. Authors’ Summary
PREOPERATIVE STAGING OF BLADDER CANCER WITH Gd-DTPA ENHANCED DYNAMIC MAGNETIC RESONANCE IMAGING: COMPARISON WITH STANDARD AND Gd-DTPA ENHANCED SPIN-ECHO SEQUENCES (In German) Venz S, Hosten N, Ilg J, et al. (Strahlenklinik u. Poliklinik, Universitgtklinikum Rudolf Virchow. Augustenburger Platz 1, D-13353 Berlin, Germany). Fortschr Riintgenstr 1996;164:218-225. The purpose of this study was to evaluate dynamic Cd-DTPA-enhanced magnetic resonance imaging (MRI) in the staging of bladder cancer. We studied 40 patients with histologically proven bladder cancer. All patients were examined with routine T,- and T,weighted MRI and late Gd-DTPA-enhanced T,weighted MRI. Additionally, a dynamic study was performed with 10 subsequent short FLASH-2-D gradient-echo sequences without delay immediately after bolus injection of Gd-DTPA. Signal intensities of the tumor and of the surrounding tissue as well as image contrast parameters were quantified. The results obtained demonstrated that the dynamic study showed a higher accuracy in the evaluation of stage pT,, to pT, cancer compared to spin-echo MRI (63 and 46%, respectively) and no difference regarding the sensitivity (87.5%). However, overstaging was a problem with both modalities. The contrast-to-noise ratio of bladder tumor and muscle was equal or significantly higher with the dynamic study compared to spin-echo MRI. A higher signal-to-contrast ratio of bladder tumor and bladder muscle was calculated for the dynamic study compared with the spin-echo MRI (p < 0.01: Mann-Whitney U test). In concluding, dynamic Gd-DTPA-enhanced MRI is recommended to be used additionally in the preoperative staging of bladder neoplasms. Authors’
Summary
CLINICAL IMAGING VOL. 20, NO. 4
ABSTRACTS
sequences. To investigate the potentials of FAT-SAT sequences in MR imaging of the upper abdomen, the authors carried out a prospective study including 129 subjects, namely 12 normal volunteers and 117 patients with different abdominal conditions. The patients were submitted to Tl-weighted SE sequences (TR 500-600 ms, TE 15 ms), T2W SE (TR1600-1730 ms, TE 80 ms), and PD SE (TR 1600-1730 ms, TE 20 ms). The images obtained with and without fat suppression were compared both qualitatively and quantitatively, with a special emphasis on the normal anatomy of the upper abdomen: we investigated the efficacy of subcutaneous and retroperitoneal fat suppression (116/129 cases, 90%), the reduction in respiratory and chemical shift artifacts (112/129 cases, 87%), and the better visualization of parenchyma (119/129 cases, 93%) and of other abdominal structures. Concerning the quantitative study, we calculated the signal-to-noise ratio (S/N) for liver, spleen, pancreas, adrenal glands, renal cortex, and medulla, the improvement of contrast in these organs after retroperitoneal fat suppression (conspicuity), and the increase in contrast between organs (dynamic range). The statistical analysis showed significant differences between the sequences with and those without fat suppression. Correlations were found between observers’ and quantitative evaluations, suggesting that the better yield of FAT-SAT sequences is probably due to three factors: (1) retroperitoneal and subcutaneous fat suppression: (2) increase in S/Nratio for pancreas and renal cortex on TlW images; (3) reduction in the dynamic range of signal intensity, which increases contrast between pancreas, adrenal glands, and renal cortex relative to adjacent structures, especially on T2W or PD sequences. The results of this study suggest that FAT-SAT sequences are useful because fat suppression increases contrast and improves image quality, reducing respiratory and chemical shift artifacts. Authors’
Summary
MRI EVALUATION OF ANO-PERINEAL FISTULAE: DIAGNOSTIC CONTRIBUTION OF T2 WEIGHTED SEQUENCES (In French) Tissot 0, Bodnar D, Henry L, et al. (Service Central de Radiologie, Centre Hospitalier GBnBral, F-44606 Saint-Nazaire Cedex, France). J Radio1 1996;77:255-260.
The role of magnetic resonance imaging (MRI) in the evaluation of anal fistulae is well recognized. In this article the authors report the data obtained by a detailed evaluation of these lesions as detected by MRI, SE TZweighted sequences. Eighteen consecutive patients with anal fistula were examined by MRI before surgery. A cryptogenetic fistula was present in 12 patients: an anoperineal fistula was related to Crohn’s disease in 4; and, in one case each, the fistula was secondary to an ulcerative hemorrhagic rectocolitis or to a pilonidal cyst. The examinations were conducted at 0.5 T. In the first two cases in Tl- and T2weighted sequences and in the remaining 16 patients only TZweighted sequences were obtained in 25 sections of 5 mm in the coronal and axial planes. Prior to the examination a balloon in the anal canal was inflated with 60 ml of air. A review of the MR images obtained showed that productive lesions (16 patients) were hyperintense in the T2 sequences, while the fistulae, which did not contain fluid, and those surrounded by cicatricial tissue were iso- or minimally hyperintense. Fissures involving the anal wall in Crohn’s disease appeared as linear hyperintense signals. If the lesion involved the supra-elevator space two images were detected, either intramural fistulous tracts extending from the anal canal with hyperintense signals or as nodular pararectal signals related to abscess formations. In 11 patients it was possible to visualize the internal orifice of the fistula when the signal became hyperintense in reaching the anal canal. Healed fistulae could not be demonstrated. The fistulae were distinguished, according to the classification proposed by Park, Gordon, and Hardcastle (Brit J Surg 1976;63:1-12), in intersphincteric (4/18), transphincteric (2/18), suprasphincteric (10/18), and extrasphincteric (l/18). The last case, an abscess involving a pilonidal cyst, did not extend to the sphincter. At surgery, the fistulous tract was simple in 8 patients and complex in 10, confirming in 4 patients the presence of an abscess in the true supralevator space. In the opinion of the authors MRI of the anal canal with SE T2-weighted sequences, in the two axial planes, is sufficient in the demonstration and characterization of anal fistulae. Numerous and clear figures illustrate the article. Antonio
F. Govoni, MD
THE ULTRASONIC DIAGNOSIS OF URACHAL ANOMALIES Holten I, Lomas F, Mouratidis B, et al. (F.L.: Woden Valley Hospital, Garran, ACT
OCTOBER-DECEMBER I996
2605, Australia). 1996:40:2-5.
Austral Radio1
Between 1982 and 1994 seven patients ranging in age between 20 months and 28 years were operated on for urachal anomalies. All patients were studied before surgery by ultrasonography (US). The procedure correctly diagnosed the pathological process in six patients. An umbilical sinus presenting with bleeding and serous discharge was not recognized. An urachal anomaly was detected in a 28-year-old pregnant woman prior to semi-elective cesarean section. The sonographic images of a fixed, midline, and predominately cystic swelling, located between the umbilicus and the bladder, and its extraperitoneal location and resistance to movements would distinguish such an anomaly from other abdominal cysts and suggest the diagnosis of a urachal anomaly. Antonio
F. Govoni,
MD
MAGNETIC RESONANCE IMAGING OF THE KIDNEY: EVALUATION OF NEW PULSE SEQUENCES AND COMPARISON WITH COMPUTED TOMOGRAPHY IN THE DIFFERENTIAL DIAGNOSIS OF SPACE OCCUPYING LESIONS (In German) Kreft B, Steudel A, Textor J, et al. (Radiologische Klinik der Universitgt Bonn, Sigmund-Freud-Str. 25, D-53127, Germany). Fortschr Riintgenstr 1996;164:212-217. The purpose of this study was to evaluate new pulse sequences (turbo-spin-echo [TSE] and turbo-fieldecho [TFE] sequences) for study protocol optimization and to assess the role of magnetic resonance imaging (MRI) in the differential diagnosis of renal tumors. In six volunteers MRI of the kidney was performed at 0.5 T using a conventional T,-weighted spin-echo (SE) sequence (T,lr, 1800/90 ms) and three different TSE sequences (TR 1800-5000 ms, Tt 90-150 ms). Additionally, computed tomography (CT) and MRI were performed in 34 patients with 41 renal masses. Two readers evaluated both images regarding the differentiation between malignant and benign masses. The pilot study showed that the heavily T,-weighted TSE sequence (TRITE 5500/150 ms) was superior to other sequences with regard to image quality and differentiation of the corticomedullary junction. In the clinical study malignant tumors were correctly classified with CT and MRI in
ABSTRACTS
293
86.4 and 95.5% of the cases, whereas the accuracy in the diagnosis of benign lesions of CT and MRI was 73.7 and 89.5%, respectively. The results obtained indicated that using new pulse sequences MRI is superior to CT in the differential diagnosis of renal tumors in the differentiation between complicated cysts and cystic or hypovascular renal cell carcinomas. Authors’ Summary
PREOPERATIVE STAGING OF BLADDER CANCER WITH Gd-DTPA ENHANCED DYNAMIC MAGNETIC RESONANCE IMAGING: COMPARISON WITH STANDARD AND Gd-DTPA ENHANCED SPIN-ECHO SEQUENCES (In German) Venz S, Hosten N, Ilg J, et al. (Strahlenklinik u. Poliklinik, Universitgtklinikum Rudolf Virchow. Augustenburger Platz 1, D-13353 Berlin, Germany). Fortschr Riintgenstr 1996;164:218-225. The purpose of this study was to evaluate dynamic Cd-DTPA-enhanced magnetic resonance imaging (MRI) in the staging of bladder cancer. We studied 40 patients with histologically proven bladder cancer. All patients were examined with routine T,- and T,weighted MRI and late Gd-DTPA-enhanced T,weighted MRI. Additionally, a dynamic study was performed with 10 subsequent short FLASH-2-D gradient-echo sequences without delay immediately after bolus injection of Gd-DTPA. Signal intensities of the tumor and of the surrounding tissue as well as image contrast parameters were quantified. The results obtained demonstrated that the dynamic study showed a higher accuracy in the evaluation of stage pT,, to pT, cancer compared to spin-echo MRI (63 and 46%, respectively) and no difference regarding the sensitivity (87.5%). However, overstaging was a problem with both modalities. The contrast-to-noise ratio of bladder tumor and muscle was equal or significantly higher with the dynamic study compared to spin-echo MRI. A higher signal-to-contrast ratio of bladder tumor and bladder muscle was calculated for the dynamic study compared with the spin-echo MRI (p < 0.01: Mann-Whitney U test). In concluding, dynamic Gd-DTPA-enhanced MRI is recommended to be used additionally in the preoperative staging of bladder neoplasms. Authors’
Summary