Changes of the normal ovary during menstrual cycle in reproductive age on the diffusion-weighted image.

OBJECTIVE: The objective of this study was to investigate changes in magnetic resonance findings of the normal ovary during menstrual cycle on diffusion-weighted image (DWI). METHODS: Magnetic resonance imaging was performed in 9 healthy females at the menstrual, periovulatory, and luteal phases using a 1.5-T unit. Signal intensity (SI) of the ovary on DWI with a b value of 1000 s/mm was visually scored. The ovary-to-muscle contrast ratios on DWI and apparent diffusion coefficient (ADC) values were also evaluated. RESULTS: All the ovaries were identified, and higher SI than the nerve root was identified in 70% (38/54) of the ovaries, although visual scores did not show significant difference among menstrual phases. The mean ADC values (10 mm/s) were 1.71 (SD, 0.27), 1.71 (SD, 0.22), and 1.67 (SD, 0.19) in menstrual, periovulatory, and luteal phases, respectively. No phase-dependent change was observed in contrast ratios and ADC values. CONCLUSION: The normal ovary in fertile period shows high SI enough to be identified on DWI, and observed values are independent of the menstrual cycle.

CT and MR features of struma ovarii.

OBJECTIVE: The purpose of this study is to investigate radiologic findings of struma ovarii, and to correlate both CT and MR findings. MATERIALS AND METHODS: MR images of 26 cases were retrospectively reviewed. Post-contrast enhanced T1-weighted images were available in 17 patients. CT images, including seven non-contrast and eleven post-contrast studies, were available for review in 13 cases. RESULTS: All 26 tumors appeared as well-defined cystic tumors with solid components, which were multilobulated surfaces in 19 and smooth surfaces in seven. Twenty-four was multicystic, whereas two were unilocular. The solid components were recognized as thickened septi or walls in 23 and a mass in three tumors. On T2-weighted images, loculi of prominent low intensity were recognized in 16 tumors. On T1-weighted images, the punctuate foci of high intensity were recognized in 24 tumors in or adjacent to the solid components. Ascites was present in only one lesion. In six of seven cases with non-contrast CT images, high attenuation areas were recognized. In five of these six tumors, high attenuation areas corresponded to the areas of prominent low intensity and the solid components on T2-weighted images. In seven cases with CT, curvilinear calcifications were recognized in the solid components. CONCLUSION: Struma ovarii typically presents as a lobulated multicystic lesion with solid components. The tumors frequently include loculi of low intensity on T2-weighted images and punctuate foci of high intensity on T1-weighted images. On CT, high attenuation areas and calcifications in the solid components are common findings.

BLADE acquisition method improves T2-weighted MR images of the female pelvis compared with a standard fast spin-echo sequence.

PURPOSE: To investigate feasibility of the periodically rotated overlapping parallel lines with enhanced reconstruction (PROPELLER or BLADE) T2-weighted imaging (T2WI) of the female pelvis by comparing it with standard fast spin-echo T2WI (STD-T2WI). MATERIALS AND METHODS: Sagittal STD-T2WI and BLADE-T2WI of the female pelvis were performed with (36 patients) or without (15 patients) administration of butylscopolamine on a 1.5 T MR unit. Two radiologists independently rated depiction of the uterus, ovary, intestines, bladder, gynecological lesions, overall quality, and artifacts using a four-point scale. Results were compared between STD-T2WI vs. BLADE-T2WI either with (B+) or without (B-) administration of butylscopolamine, BLADE-T2WI (B-) vs. BLADE-T2WI (B+), and STD-T2WI (B+) vs. BLADE-T2WI (B-). RESULTS: When butylscopolamine was administrated, depiction of the uterus, ovary, intestines, gynecological lesions, and overall image quality was rated higher and artifacts were rated fewer for BLADE-T2WI with significance compared with STD-T2WI. When the drug was not administrated, significant difference was observed in depiction of the lesion, overall quality, and artifacts. Depiction of the uterus, gynecological lesion, and overall quality was rated significantly higher and artifacts were fewer in BLADE-T2WI (B+) than in BLADE-T2WI (B-). CONCLUSION: BLADE method was feasible for female pelvic MRI, with best image quality in BLADE-T2WI (B+).

Diffusion tensor MRI of the kidney at 3.0 and 1.5 Tesla.

BACKGROUND: Diffusion tensor imaging (DTI) at 3 T provides information on the microstructure and pathophysiology of tissues that is not available from conventional imaging with an advantage of high signal to noise ratio (SNR). PURPOSE: To evaluate the feasibility of DTI of the normal kidney at 3.0 T compared to results obtained at 1.5 T. MATERIAL AND METHODS: DTI of the normal kidney of 15 healthy volunteers obtained with 3.0 and 1.5 T scanners using respiration-triggered acquisition was examined. Fractional anisotropy (FA) and apparent diffusion coefficient (ADC) values of both the renal cortex and the medulla and SNRs were measured (b-values 0 and 400 s/mm², diffusion direction of 6). The image quality of FA and ADC maps was also compared subjectively. RESULTS: The FA values of the renal cortex were 0.15 ± 0.03 at 3.0 T and 0.14± 0.03 at 1.5 T on average. This difference was not significant. The FA values of the renal medulla were 0.49 ±0.04 at 3.0 T and 0.42 ± 0.05 at 1.5 T. ADC values of the renal cortex were 2.46 x 10⁻³± 0.09 mm<²/s at 3.0 T and 2.20 x 10⁻³±0.11 mm²/s at 1.5 T. The ADC values of the renal medulla were 2.08 x 10⁻³ ± 0.08 mm²/s at 3.0 T and 1.90 x 10⁻³± 0.11 mm²/s at 1.5 T. These FA and ADC values were consistent with previous publications. The difference was significant for the FA value of the medulla (P< 0.01) and ADC values in both cortex and medulla (P < 0.01). The subjective image quality of the FA map with the 3.0 T scanner was significantly superior to that with the 1.5 T scanner (P< 0.01), but not significant for the ADC map (P = 0.18). There was a significant difference in SNR between 3.0 T (48.8 ± 6.6) and 1.5 T images (32.8 ± 5.0). CONCLUSION: The feasibility of renal DTI with a 3.0 T magnet resulting in improved SNR was demonstrated.

Diffusion tensor imaging of kidneys with respiratory triggering: optimization of parameters to demonstrate anisotropic structures on fraction anisotropy maps.

PURPOSE: To demonstrate the feasibility of diffusion tensor imaging (DTI) of kidneys with respiratory triggering, and determine the optimal imaging parameters for fraction anisotropy (FA) maps. MATERIALS AND METHODS: DTI of kidneys from 16 healthy volunteers was performed using a 1.5T scanner. Five different sequences with different parameters including respiration-triggered acquisition or multiple breath-holding, slice thicknesses of 3 or 5 mm, and different numbers of signal averaging and b values were compared. FA and apparent diffusion coefficients (ADCs) of the cortex and medulla were measured. Measurement error within the same and repeated examination was examined using within-individual standard deviation (Sw). RESULTS: FAs of the renal cortex were lower than the medulla (mean value of a sequence ranging 0.148-0.224, 0.433-0.476) and the ADCs of the cortex were higher than the medulla (2.26-2.69x10(-3) mm2/s, 1.77-2.19x10(-3) mm2/s) in all sequences (P<0.001). The renal cortex-medulla difference was the largest, with respiratory trigger- ing including a 3-mm slice thickness, three signal averages,and a b-value=0, 200, or 400 s/mm2 (P<0.001). Sw tended to be smaller in the sequence with a b-value of 400 s/mm2. CONCLUSION: DTI of kidneys with respiratory triggering is feasible with excellent cortex-medulla differentiation.

Clinical value of image fusion from MR and PET in patients with head and neck cancer.

PURPOSE: This study aimed to evaluate the clinical value of image fusion from magnetic resonance (MR) combined with positron emission tomography (PET) imaging, using 2-deoxy-2-[F-18]fluoro-D-glucose (FDG) in head and neck cancer. METHODS: Sixty-five consecutive patients underwent MR and FDG-PET scans before or after the treatment of known or suspected head and neck cancer. T1-weighted and T2-weighted images were first assessed by MR interpretation, and then, the fused images of T2-weighted images from MR and PET were evaluated in a blind manner. Diagnostic performance was compared. PROCEDURES: For initial staging, in 48 patients, malignant tumors were histologically confirmed in 45 patients. The interpretation sensitivities of MR alone and fused images for primary tumors were 98% and 100%, respectively. For lymph node metastasis, the sensitivity and specificity of both methods were 85% and 92%, respectively. Of 15 patients with suspected recurrence, ten patients had recurrent tumors, three patients developed second malignant tumors, and two patients had no recurrence. For these patients, the overall sensitivity of MR alone was 67%, whereas that of the fused images was 92%. Eight additional lesions were accurately diagnosed by image fusion only. In two patients with lymph node metastasis from unknown origin, the primary site was not detected in one patient, while tonsilar cancer was identified only by image fusion interpretation. CONCLUSION: Image fusion from MR with PET might be useful in evaluating head and neck cancer, especially in suspected recurrent cases rather than in fresh cases.

A case of Sertoli-Leydig cell tumour of the ovary with a multilocular cystic appearance on CT and MR imaging.

We present a case of Sertoli-Leydig cell tumour of the ovary in a 14-year-old girl who presented with abdominal distension. Ultrasonography showed a multilocular cystic lesion filled with finely echogenic fluid. Contrast-enhanced CT demonstrated a huge multilocular cystic mass with thickened septa. At MR imaging, the capsule of the cyst was focally thickened, showing intermediate signal intensity on T2-W images. Although extensive cyst formation of Sertoli-Leydig cell tumour is rare, this tumour should be considered in the differential diagnosis of a multilocular cystic ovarian tumour in a young female.

The utility of diffusion-weighted MR imaging for differentiating uterine sarcomas from benign leiomyomas.

The usefulness of diffusion-weighted (DW) magnetic resonance (MR) imaging for the diagnosis of uterine sarcomas was investigated, as well as whether DW images and quantitative measurement of apparent diffusion coefficient (ADC) values can facilitate differentiating uterine sarcomas from benign leiomyomas. MR images including DW images were obtained in 43 surgically treated patients with 58 myometrial tumors, including seven uterine sarcomas (five leiomyosarcomas and two endometrial stromal sarcomas) and 51 benign leiomyomas (43 ordinary leiomyomas, two cellular leiomyomas and six degenerated leiomyomas). Qualitative analysis of non-enhanced and postcontrast MR images and DW images and quantitative measurement of ADC values were performed for each myometrial tumor. Both uterine sarcomas and cellular leiomyomas exhibited high signal intensity on DW images, whereas ordinary leiomyomas and most degenerated leiomyomas showed low signal intensity. The mean ADC value (10(-3) mm(2)/s) of sarcomas was 1.17 +/- 0.15, which was lower than those of the normal myometrium (1.62 +/- 0.11) and degenerated leiomyomas (1.70 +/- 0.11) without any overlap; however, they were overlapped with those of ordinary leiomyomas and cellular leiomyomas. In addition to morphological features on nonenhanced and postcontrast MR sequences, DW imaging and ADC measurement may have a potential ability to differentiate uterine sarcomas from benign leiomyomas.

High-resolution computed tomography findings of diffuse pulmonary involvement by mycosis fungoides.

The authors describe a case of diffuse pulmonary involvement by mycosis fungoides in a 55-year-old man who presented with progressive exertional dyspnea. Although he had a long history of skin lesions, mycosis fungoides remained undiagnosed at initial presentation. High-resolution computed tomography revealed hazy ground-glass opacities along the thickened bronchovascular bundles and interlobular septa, particularly in the mid and upper lung fields, and traction bronchiectasis in the central regions. Skin biopsy confirmed the diagnosis of mycosis fungoides in the plaque stage. Transbronchial lung biopsy revealed diffuse infiltration of the atypical lymphoid cells in the peribronchial and perivascular regions. In this case, high-resolution computed tomography played an important role for suggesting the lymphoproliferative disease in this patient with undiagnosed mycosis fungoides.

MR imaging of the female pelvis at 3 Tesla: evaluation of image homogeneity using different dielectric pads.

PURPOSE: To evaluate improvements in image homogeneity in pelvic MR imaging at 3 Tesla (T) using two different dielectric pads. MATERIALS AND METHODS: A total of eight healthy females were scanned using a 3T MR scanner equipped with a body-array coil. Axial and sagittal fast spin-echo T2-weighted images (T2WI) (TR/TE = 3200 msec/94 msec), axial fast spin-echo T1-weighted images (T1WI) (TR/TE = 700 msec/11 msec), and sagittal half-Fourier acquisition single-shot turbo spin-echo (HASTE) images (TR/TE = 3000 msec/100 msec) were performed for pelvic imaging. Sequences were repeated with dielectric pads (consisting of either ultrasound [US] gel or water), and without pads. Three or four regions of interest (ROIs) were placed on fatty tissues and the ratio of minimum to maximum signal intensity (RSI) was calculated as a marker of image homogeneity. RESULTS: RSI was significantly higher on T2WI and T1WI when using dielectric pads than when no pad was used. A similar tendency was observed in RSI on HASTE. No significant difference was found between images with US gel pads and those with water pads. CONCLUSION: Dielectric pads consisting of either US gel or water are effective in improving image homogeneity of the pelvis on 3T MRI.

MR features of ectopic pregnancy.

Ectopic pregnancy (EP), in which a fertilized ovum implants outside the uterine cavity, is the leading cause of pregnancy-related death in the first trimester. EP is usually suspected by a positive pregnancy test and an empty uterus on transvaginal sonography (TVS). Although TVS is the initial modality of choice, it may occasionally fail to demonstrate the implantation site. When TVS findings are indeterminate, magnetic resonance imaging (MRI) may provide better delineation of the focus of EP owing to its excellent tissue contrast. The key MRI features of EP include gestational sac (GS)-like structures that typically appear as a cystic sac-like structure, frequently associated with surrounding acute hematoma of distinct low intensity on T2-weighted images. In tubal pregnancy, an enhanced tubal wall on postcontrast images may be another diagnostic finding. Ruptured EP is inevitably associated with acute hematoma outside these structures. In intrauterine EP, recognition of the relationship between GS-like structure and the myometrium can aid in differentiating from normal pregnancy. Diagnostic pitfalls include heterotopic pregnancy, decidual changes in endometrial cyst and theca lutein cysts mimicking GS-like structures. Knowledge of a spectrum of clinical and MRI features of EP is essential for establishing an accurate diagnosis and determining appropriate management.

Diffusion-weighted MR imaging of uterine endometrial cancer.

PURPOSE: To determine the feasibility of diffusion-weighted (DW) MRI of uterine endometrial cancer and to investigate whether the apparent diffusion coefficient (ADC) values of endometrial cancer differ from those of normal endometrium and whether they differ according to the histologic grade of the tumor. MATERIALS AND METHODS: Study population included 18 consecutive females with surgically proven endometrial cancer and 12 females with pathologically confirmed normal endometrium in cervical cancer patients. Visual evaluation and ADC measurement were performed in endometrial cancer and normal endometrium. RESULTS: All endometrial cancer and the normal endometrium appeared hyperintense on DW images. The mean ADC value (10(-3) mm(2)/second) of endometrial cancer was 0.88 +/- 0.16, which was significantly lower (P < 0.01) than that of normal endometrium (1.53 +/- 0.10). The mean ADC value for each histologic grade was 0.93 +/- 0.16 (G1), 0.92 +/- 0.13 (G2), and 0.73 +/- 0.09 (G3). CONCLUSION: The present study showed that DW imaging is feasible in demonstrating uterine endometrial cancer and ADC measurement has a potential ability to differentiate between normal and cancerous tissue of the endometrium. The ADC values of endometrial cancers of higher grade show tendency to decrease compared to those of lower grade, although estimation of histologic grade based on ADC values seems difficult because of considerable overlap.

MR imaging findings of eosinophilic cystitis in an 8-year-old girl.

Eosinophilic cystitis is a rare inflammatory condition of the urinary bladder of unknown aetiology and characterized by eosinophilic infiltration of the bladder wall. We report the unique MR findings of eosinophilic cystitis in an 8-year-old girl who presented with peripheral eosinophilia. MR imaging revealed smooth and nearly circumferential thickening of the bladder wall showing distinct low signal intensity on T2-weighted images, which may histologically represent high cellularity due to massive eosinophilic infiltration.

Small cell carcinoma of the uterine corpus: MR imaging and pathological correlation.

Small cell carcinoma of the uterine corpus is a rare but aggressive neoplasm showing neuroendocrine differentiation; its radiological findings are not well described. We report the magnetic resonance features of 3 cases with pathological correlation. Small cell carcinoma is shown as a bulky endometrial tumor of heterogeneous appearance on T2-weighted images, frequently associated with diffuse myometrium invasion and early extrauterine spread. Irregular enhancement with multifocal unenhanced areas of the thickened myometrium on contrast-enhanced T1-weighted images may represent the infiltrative nature of the tumor with extensive necrosis.

MRCP imaging at 3.0 T vs. 1.5 T: preliminary experience in healthy volunteers.

PURPOSE: To evaluate the impact of magnetic resonance cholangiopancreatography (MRCP) imaging at 1.5T and 3.0T on image quality. MATERIALS AND METHODS: Fourteen volunteers were examined at both 1.5T and 3.0T using MRCP imaging performed with a breath-held two-dimensional (2D) half-Fourier acquired single-shot turbo spin-echo (HASTE) thick-slab sequence, a free-breathing navigator-triggered three-dimensional (3D) turbo spin-echo (TSE) sequence with prospective acquisition correction, and a heavily T2-weighted (T2W) sequence with breath-held multislice HASTE. All images were scored for visualization of the biliary and pancreatic ducts, severity of artifacts, image noise, and overall image quality. RESULTS: MRCP imaging at 3.0T yielded a significant improvement in overall image quality compared to 1.5T. We found a trend for superior visualization of the biliary and pancreatic ducts at 3.0T. Heavily T2W imaging with thin sections (1.4 mm) at 3.0T provided diagnostic images and better visualization of the biliary and pancreatic ducts than heavily T2W imaging with standard sections (2.8 mm) at 3.0T. CONCLUSION: Our experience suggests that MRCP imaging at 3.0T has the potential to provide excellent images. High-resolution heavily T2W imaging with a small voxel size (1.3 x 1.3 x 1.4 mm) at 3.0T can provide diagnostic images and allow evaluation of small pathologies of the bile and pancreatic ducts, which 1.5T MRI cannot sufficiently visualize.

Secondary ovarian tumors: spectrum of CT and MR features with pathologic correlation.

The ovaries represent common sites for metastatic disease. The common primary sites for metastatic disease to the ovaries include the colon, stomach, breast, and the genitourinary tract. Hematologic malignancies, including lymphoma and leukemia, also involve the ovaries. Ovarian metastasis may occasionally represent the initial manifestation of disease, especially in cancers of the gastrointestinal tract. The accurate diagnosis of this condition is always crucial since the misinterpretation of such tumors may cause significant adverse consequences for patients. CT and MR features of secondary ovarian tumors differ according to the origins of the primary malignancies. The great majority of metastases from gastric cancer are Krukenberg tumors, which are typically bilateral and characterized by lobulated solid tumors. Metastases from colon cancer are usually cystic tumors with solid components of variable size. Metastases from appendiceal tumor may present as ruptured mucinous ovarian tumors associated with pseudomyxoma peritonei. Metastatic tumors from breast cancer are characterized by the relatively small size of the lesion. Ovarian involvement by hematologic malignancies is typically bilateral, homogeneous solid masses. Recognition of radiologic features of a variety of secondary ovarian tumors is beneficial for suspecting the secondary tumors under certain clinical conditions, and thus determining the appropriate management of the patients.

MRI of the female pelvis at 3T compared to 1.5T: evaluation on high-resolution T2-weighted and HASTE images.

PURPOSE: To evaluate the feasibility of MRI of the female pelvis using high-resolution T2-weighted imaging (T2WI) and the half-Fourier acquisition single-shot turbo spin-echo (HASTE) technique at 3 Tesla (T) compared to 1.5T, while focusing on the uterine body and cervical anatomy. MATERIALS AND METHODS: A total of 19 healthy women underwent pelvic MR scans on 3T and 1.5T scanners. Axial and sagittal T2W (voxel size of 0.6 x 0.8 x 2 mm) and sagittal HASTE images were obtained. The images were evaluated qualitatively for overall image quality, contrast in the uterine zonal appearance and cervical structure, image inhomogeneity, and artifacts. A quantitative evaluation was performed regarding zonal contrast and image inhomogeneity. RESULTS: On T2WI, the image contrast in the uterine cervix and vagina were significantly higher at 3T than at 1.5T, although there was no significant difference in the overall image quality or contrast in the uterine zonal appearance. Image inhomogeneity was more prominent at 3T, and motion artifact was more severe at 1.5T. CONCLUSION: Our results suggest that MRI of the female pelvis at 3T may potentially provide excellent images of the uterine cervix on high-resolution T2WI. New techniques to reduce inhomogeneity are thus called for.

Staging of carcinoma of the uterine cervix and endometrium.

Carcinoma of the uterine cervix and endometrium are common gynecologic malignancies. Both carcinomas are staged and managed by means of the International Federation of Gynecology and Obstetrics (FIGO) staging system. In uterine cervical cancer, the FIGO staging system is determined preoperatively by limited conventional procedures. Although this system is effective for early stage disease, it has inherent inaccuracies in advanced stage diseases and does not address nodal involvement. CT and MR imaging are widely used as comprehensive imaging modalities to evaluate tumor size and extent, and nodal involvement. MR imaging is an excellent modality for depicting invasive cervical carcinoma and can provide objective measurement of tumor volume, and provides high negative predictive value for parametrial invasion and stage IVA disease. In contrast, endometrial cancer is surgically staged. Beside recognition of the important prognostic factors, including histologic subtype and grade, accurate assessment of the tumor extent on preoperative MR imaging is expected to greatly optimize surgical procedure and therapeutic strategy. Contrast-enhanced MR imaging can offer "one stop" examination for evaluating the depth of myometrial invasion cervical invasion and nodal metastases. Evaluation of myometrial invasion on MR imaging may be an alternative to gross inspection of the uterus during the surgery.

Current status of body MR imaging: fast MR imaging and diffusion-weighted imaging.

The recent technical advances in fast MR imaging have greatly enhanced the clinical value of MR imaging of the body. Advances in T(1)-weighted images have enabled the acquisition of dynamic contrast-enhanced MR imaging, which is currently central to hepatic MR imaging for detection and characterization of liver tumors and is also useful for the evaluation of myometrial invasion in uterine cor-pus cancer. Advances in rapid T(2)-weighted MR imaging with single-shot fast spin-echo images have enabled MR cholangiopancreatography and MR urography. Application of respiratory triggering can also provide T(2)-weighted images of high quality. Cine MR imaging utilizing ultrafast MR sequences enables the assessment of the respiratory motion of the lung for evaluating thoracic wall invasion by tumors. Diffusion-weighted images can provide excellent tissue contrast based on molecular diffusion and have the potential to demonstrate malignant tumors. Quantitative measurement of apparent diffusion coefficient values may also be valuable in distinguishing malignancies from benign lesions.