Letters to the Editor 184 Ultrasound in Obstetrics and Gynecology adenomyosis and the consequence of metaplasia of Müllerian remnants. Vesical endometriosis may infiltrate the bladder wall or ureters and cause obstructive uropathy. Therefore, early recognition of this disorder can avoid serious morbidity. Differential diagnosis of vesical endometriosis includes epithelial tumors of the bladder mucosa, hemangioma, fibroma, leiomyoma of the detrusor and uterine myoma of the anterior wall 6 . Preoperative assessment of vesical endometriosis can be made by transabdominal and transvaginal sonography, magnetic resonance imaging, urography and computed tomography 6–12 . Fedele et al. 6 suggested that transvaginal sonography is the most accurate technique in the diagnosis of vesical endometriosis because the better image resolution allows an accurate structural analysis of the bladder wall lesion and a precise evaluation of the uterovesical septum and adjacent myometrial infiltration. In the present case, transvaginal sono- graphy identified the heterogeneous echostructures of the bladder lesion and revealed its microcystic structures. In conclusion, we successfully identified previously over- looked vesical endometriosis by transvaginal sonography in a woman with dysmenorrhea. Our presentation shows the importance of simultaneous evaluation of the bladder in addition to the uterus and adnexa in patients with known or suspected pelvic endometriosis. With careful sonographic examinations of the bladder, we believe that more cases of vesical endometriosis can be detected early. C.-P. Chen*¶, H.-K. Chang†, C.-Y. Sheu‡, B.-F. Chen§, S.-J. Chang* and W. Wang¶ Departments of *Obstetrics and Gynecology, †Urology, ‡Radiology, §Pathology, and ¶Medical Research, Mackay Memorial Hospital, Taipei, Taiwan, Republic of China References 1 Aldridge KW, Burns JR, Singh B. Vesical endometriosis: a review and 2 case reports. J Urol 1985; 134: 539 – 41 2 Shook TE, Nyberg LM. Endometriosis of the urinary tract. Urology 1988; 31: 1– 6 3 Sircus TE, Sant GR, Ucci AA. Bladder detrusor endometriosis mim- icking interstitial cystitis. Urology 1988; 32: 339 – 42 4 Fein RL, Horton BF. Vesical endometriosis: a case report and review of the literature. J Urol 1966; 95: 45–50 5 Donnez J, Spada F, Squifflet J, Nisolle M. Bladder endometriosis must be considered as bladder adenomyosis. Fertil Steril 2000; 74: 1175– 81 6 Fedele L, Bianchi S, Raffaelli R, Portuese A. Pre-operative assessment of bladder endometriosis. Hum Reprod 1997; 12: 2519 –22 7 Kinkel K, Chapron C, Balleyguier C, Fritel X, Dubuisson J-B, Moreau J-F. Magnetic resonance imaging characteristics of deep endometriosis. Hum Reprod 1999; 14: 1080 – 6 8 Schwartzwald D, Mooppan UM, Ohm HK, Kim H. Endometriosis of bladder. Urology 1992; 39: 219–22 9 Whitman GJ, McGovern FJ. Endometriosis of the bladder detected by pelvic ultrasonography. J Ultrasound Med 1994; 13: 155 –7 10 Siegelman ES, Outwater E, Wang T, Mitchell DG. Solid pelvic masses caused by endometriosis: MR imaging features. AJR Am J Roentgenol 1994; 163: 357 – 61 11 Vercellini P, Meschia M, De Giorgi O, Panazza S, Cortesi I, Crosignani PG. Bladder detrusor endometriosis: clinical and patho- logic implications. J Urol 1996; 155: 84 – 6 12 Price DT, Maloney KE, Ibrahim GK, Cundiff GW, Leder RA, Anderson EE. Vesical endometriosis: report of two cases and review of the literature. Urology 1996; 48: 639 – 43 18 2001 483 Letters to the Editor Letters to The Editor 000 000 Graphicraft Limited, Hong Kong Letters to The Editor Ductus venosus blood velocity in myeloproliferative disorders Myeloproliferative conditions in trisomy 21 are probably under-reported in the literature. Thus, the article of Smrcek et al. 1 showing that three of 79 fetuses with trisomy 21 were affected is an excellent presentation boosting our awareness of the condition. However, the authors used the waveform of the ductus venosus blood flow velocity as one of their Doppler parameters, but did not use this Doppler measurement to its full diagnostic potential. From a physiological point of view, the pulsatility of the ductus venosus blood flow reflects mainly cardiac function, whereas absolute velocities reflect the umbilicocaval pressure gradient (i.e. portocaval pressure gradient) 2–6 . In our experience, parenchymal liver diseases (e.g. myeloproliferative disorder, mitochondrial liver disease, viral liver inflammation) lead to some of the highest velocities measured in the ductus venosus (typically a peak systolic velocity of 1–1.3 m /s) 3 . Although Smrcek and collaborators did not report absolute blood velocities, the Doppler recording in Figure 3b of their article illustrates the phenomenon well. This sonogram shows a peak systolic velocity of 1.04 m/s in the ductus venosus (possibly higher if the recording was not adjusted for angle of insonation), which is clearly above normal ranges for 28 weeks of gestation 7 . Parenchymal liver disorders (including augmented erythropoietic activity 8 ) are expected to increase vascular resistance and to be associated with an increased umbilical venous pressure. Since such changes are not detected by waveform analysis but rather by absolute blood velocity in the ductus venosus, this measurement is recommended as a useful diagnostic supplement in such cases. T. Kiserud Fetal Medicine Unit, Department of Obstetrics and Gynecology, Bergen University Hospital, POB 1, N-5021 Bergen, Norway Figure 3 Histological section of the specimen reveals endometrial glands and stroma (hematoxylin–eosin stain, original magnification ×200).