Correlations of Dynamic Contrast-Enhanced Magnetic Resonance Imaging with Morphologic, Angiogenic, and Molecular Prognostic Factors in Rectal Cancer

PURPOSE: To investigate the correlations between parameters of dynamic contrast-enhanced magnetic resonance imaging (DCE-MRI) and prognostic factors in rectal cancer. MATERIALS AND METHODS: We studied 29 patients with rectal cancer who underwent gadolinium contrast-enhanced, T1-weighted DCE-MRI with a three Tesla scanner prior to surgery. Signal intensity on DCE-MRI was independently measured by two observers to examine reproducibility. A time-signal intensity curve was generated, from which four semiquantitative parameters were calculated: steepest slope (SLP), time to peak (Tp), relative enhancement during a rapid rise (Erise), and maximal enhancement (Emax). Morphologic prognostic factors including T stage, N stage, and histologic grade were identified. Tumor angiogenesis was evaluated in terms of microvessel count (MVC) and microvessel area (MVA) by morphometric study. As molecular factors, the mutation status of the K-ras oncogene and microsatellite instability were assessed. DCE-MRI parameters were correlated with each prognostic factor using bivariate correlation analysis. A p-value of <0.05 was considered significant. RESULTS: Erise was significantly correlated with N stage (r=-0.387 and -0.393, respectively, for two independent data), and Tp was significantly correlated with histologic grade (r=0.466 and 0.489, respectively). MVA was significantly correlated with SLP (r=-0.532 and -0.535, respectively) and Erise (r=-0.511 and -0.446, respectively). MVC was significantly correlated with Emax (r=-0.435 and -0.386, respectively). No significant correlations were found between DCE-MRI parameters and T stage, K-ras mutation, or microsatellite instability. CONCLUSION: DCE-MRI may provide useful prognostic information in terms of histologic differentiation and angiogenesis in rectal cancer.

Image Quality Improvement after Implementation of a CT Accreditation Program

OBJECTIVE: The purpose of this study was to evaluate any improvement in the quality of abdominal CTs after the utilization of the nationally based accreditation program. MATERIALS AND METHODS: Approval was obtained from the Institutional Review Board, and informed consent was waived. We retrospectively analyzed 1,011 outside abdominal CTs, from 2003 to 2007. We evaluated images using a fill-up sheet form of the national accreditation program, and subjectively by grading for the overall CT image quality. CT scans were divided into two categories according to time periods; before and after the implementation of the accreditation program. We compared CT scans between two periods according to parameters pertaining to the evaluation of images. We determined whether there was a correlation between the results of a subjective assessment of the image quality and the evaluation scores of the clinical image. RESULTS: The following parameters were significantly different after the implementation of the accreditation program: identifying data, display parameters, scan length, spatial and contrast resolution, window width and level, optimal contrast enhancement, slice thickness, and total score. The remaining parameters were not significantly different between scans obtained from the two different periods: scan parameters, film quality, and artifacts. CONCLUSION: After performing the CT accreditation program, the quality of the outside abdominal CTs show marked improvement, especially for the parameters related to the scanning protocol.

Metastatic Gastric Linitis Plastica from Bladder Cancer Mimicking a Primary Gastric Carcinoma: a Case Report

Primary gastric carcinoma is the most common cause of linitis plastica. Less frequently, metastatic gastric cancer from the breast, omental metastases and non-Hodgkin lymphoma involving the stomach have been reported to show similar radiographic findings as for linitis plastica. A metastatic gastric cancer from bladder cancer is extremely rare. We present an unusual case, the first to our knowledge, of gastric linitis plastica that resulted from a metastatic urothelial carcinoma of the bladder.

Benign Lymphoproliferative Disorder of the Perirenal Space and Renal Sinus in Sjogren's Syndrome: A Case Report

We report a case of benign lymphoproliferative disease involving the perirenal space and renal sinus in patients with Sjogren's syndrome, which simulated malignant lymphoma. CT scans revealed homogeneous soft tissue masses in both renal sinuses and perirenal thin band-like lesions. An ultrasonogrphy revealed thin hypoechoic rims along the capsule of both kidneys as well as hypoechoic masses filled in renal sinuses. The lesions completely regressed following steroid treatment. Although rare, since these benign lymphoproliferative disorders with a similar appearance to lymphoma can occur in patients with Sjogren's syndrome, pathological biopsies should be performed.

Retraction: Metabolic Alterations in Parkinson's Disease after Thalamotomy, as Revealed by 1H MR Spectroscopy

No Abstract Available.

The Usefulness of Mammography and Scintimammography in Differential Diagnosis of Breast Tumor / 대한핵의학회잡지

PURPOSE: It is very important to differentiate breast cancer from benign mass. There are many reports to evaluate the differential diagnosis under the several diagnostic tools. We evaluated the usefulness of mammography and Tc-99m MIBI scintimammography in the differential diagnosis of breast mass and correlated with pathologic findings. MATERIALS AND METHODS: This study included 80 patients (age: 24-72, mean: 48.4) who underwent mammography and Tc-99m MIBI scintimammography for breast masses. Scintimammographies (anterior-posterior and lateral projections) were acquired in 10 minutes and 2 hours after intravenous injection of Tc-99m MIBI. Four specialists in diagnostic radiology and nuclear medicine evaluated the findings of breast masses under the mammography and Tc-99m MIBI scintimammography, and calculated the tumor to background (T/B) ratio. The pathologic results were obtained and we statistically analyzed the correlations between pathologic results and imaging findings under the mammography and Tc-99m MIBI scintimammography by chi-square and correlation test. RESULTS: The sensitivity, specificity, positive predictive value, and negative predictive value of mammography for detection of breast cancer were 87.5%, 56.3%, 75.0%, and 75.0% respectively. 45 cases of 80 patients were suspicious for breast cancer under the Tc-99m MIBI scintimammography. 41 cases of 45 patients were confirmed as breast cancer and the remaining 4 cases were confirmed as benign masses. The sensitivity, specificity, positive predictive value and negative predictive value of Tc-99m MIBI scintimammography for detection of breast cancer were 85.4%, 87.5%, 91.1%, and 80.8% respectively. The sensitivity of scintimammography was lower than that of mammography for detection of breast cancer, however the specificity, positive predictive value, and negative predictive value were higher. In the benign mass, the mean T/B ratio in 10 minutes was 1.409 +/- 0.30, and that in 2 hours was 1.267 +/- 0.42. The maximal T/B ratio of benign mass in 10 minutes was 1.604 +/- 0.42, and that in 2 hours was 1.476 +/- 0.50. In the malignant mass, the mean T/B ratio in 10 minutes was 2.220 +/- 1.07, and that in 2 hours was 1.842 +/- 0.75. The maximal T/B ratio of malignant mass was 2.993 +/- 1.94, and that in 2 hours was 2.480 +/- 1.34. And the T/B ratio under the early and delayed images were meaningful. CONCLUSION: The scintimammography is useful diagnostic tool to differentiate breast cancer from benign mass, although the sensitivity of mammography for detection of breast mass is high. Especially, the use of the T/B ratio is helpful to diagnose breast cancer.

MR Imaging Findings of Leiomyoma in the Prevesical Space: Case Report

Leiomyomas most frequently occur in the genitourinary and gastrointestinal system. This report describes the clinical and imaging findings of a leiomyoma originating in the prevesical space, a rare location. The mass abutted the fundus of the uterus, but after the correct identification of feeding vessels from the right iliac artery, prevesical leiomyoma was diagnosed radiologically.

Orthotopic Neobladder Reconstrution: Postoperative CT Appearance, Complications and Potential Pitfalls

PURPOSE: To evaluate the postoperative CT appearance, complications and potential pitfalls of radical cystectomy with orthotopic neobladder reconstruction. MATERIALS AND METHODS: We examined 46 patients [43 men and 3 women aged 34-72 (mean, 56.7) years] who had undergone neobladder reconstruction (ileocolic neobladder in 25 patients and ileal-W neobladder in 21). The CT scans were assessed in terms of their depiction of normal anatomy, namely the shape, location and internal architecture of the neobladder, the location of bladder bases, and the ureteral course. Early and late complications were also assessed. RESULTS: The characteristics of ileocolic neobadder were a right-side location, a lobulated outer margin, internal projections due to haustra or plication, a base in the retropubis, and right-side insertion of both ureters. In contrast, the characteristics of an ileal-W neobladder were a central location, an ovoid shape, nodular thickening at the ureteral insertion site, internal projections due to plication, and a retropubic bladder base. Early complications included hematoma with abscess formation (n=2), and postoperative peritonitis (n=1), while late complications were hydronephrosis due to stricture at the ureteral anastomotic site (n=16), tumor recurrence at this site (n=1), distal ureteral stone (n=1), mucus urinary retention (n=1), incisional hernia (n=2), tumor recurrence in the pelvic side wall (n=1), carcinomatosis peritonei (n=1), and liver metastasis (n=2). CONCLUSION: A knowledge of normal anatomic changes is essential for the accurate interpretation of CT scans. CT is a useful modality for the evaluation of postoperative change and the complications occurring in patients who have undergone radical cystectomy with othotopic neobladder reconstruction.

CT and MR Imaging Findings of Endometrial Stromal Sarcomas

PURPOSE: To evaluate the imaging findings of endometrial stromal sarcoma (ESS) according to histopathologic grade. MATERIALS AND METHODS: Six patients with pathologically proven ESS were included in this study. The histopathologic diagnosis was low-grade ESS for three patients and high-grade ESS for the three others. Preoperative CT or MR images were evaluated in terms of tumor size, location, growth pattern, the presence of hemorrhage or necrosis, status of the endometrial cavity, and invasion of surrounding structures. The imaging features of ESSs, which varied according to their histopathologic grade, were compared. RESULTS: The mean maximal diameter of low-and high-grade ESSs was 6 cm and 11.2 cm, respectively. All three low-grade ESSs were located mainly in the myometrium, but two high-grade ESSs were situated in the endometrial cavity and associated with focal tumor extension into the myometrium. One high-grade ESS had completely replaced the uterus. Low-grade ESSs were relatively well-defined, but high-grade ESSs had an irregular and lobulated margin. Intratumoral hemorrhage and necrosis were, respectively, found in two and three high-grade ESSs. Widening of the endometrial cavity was noted in all three high-grade ESSs, and lymph node metastasis had occurred in one. CONCLUSION: The imaging findings of ESS vary from a well-defined intramural mass to a bulky infiltrating mass, and depend on their histopathologic grade.

Imaging Diagnosis of Gastric Cancer: CT Scan

Gastric cancer is one of the cancers occurring most frequeently in Korea, and the diagnosis and staging of the cancer, required in order to determine the best method of treatment and the prognosis, are very important. For staging, CT scanning has been widely used, and in this report the author describes the techniques and procedures involved, investigating the accuracy and limitations of modality in both the diagnosis and staging of this disease.

Metabolic Alterations in Parkinson's Disease after Thalamotomy, as Revealed by 1H MR Spectroscopy

OBJECTIVE: To determine, using proton magnetic resonance spectroscopy (1H MRS) whether thalamotomy in patients with Parkinson's disease gives rise to significant changes in regional brain metabolism. MATERIALS AND METHODS: Fifteen patients each underwent stereotactic thalamotomy for the control of medically refractory parkinsonian tremor. Single-voxel 1H MRS was performed on a 1.5T unit using a STEAM sequence (TR/TM/TE, 2000/14/20 msec), and spectra were obtained from substantia nigra, thalamus and putamen areas, with volumes of interest of 7-8ml, before and after thalamotomy. NAA/Cho, NAA/Cr and Cho/Cr metabolite ratios were calculated from relative peak area measurements, and any changes were recorded and assessed. RESULTS: In the substantia nigra and thalamus, NAA/Cho ratios were generally low. In the substantia nigra of 80% of patients (12/15) who showed clinical improvement, decreased NAA/Cho ratios were observed in selected voxels after thalamic surgery (p < 0.05). In the thalamus of 67% of such patients (10/15), significant decreases were also noted (p < 0.05). CONCLUSION: Our results suggest that the NAA/Cho ratio may be a valuable criterion for the evaluation of Parkinson's disease patients who show clinical improvement following surgery. By highlighting variations in this ratio, 1H MRS may help lead to a better understanding of the pathophysiologic processes occurring in those with Parkinson's disease.

Role of MRI in Gastric Cancer as a Diagnostic Tool

No abstract available.

The Effect of Ethanol and Microwave Treated into the Feline Brain on Brain MRI

OBJECTIVE: The purpose of this study is to ascertain whether magnetic resonance(MR) images taken after ethanol injection or microwave irradiation into feline brain can verify changes within the brain and offer valuable information about the spatial extent of the induced lesion. METHODS: In the ethanol injection experiment, nine male cats were divided into three groups including group I(n =3) treated with 0.1cc ethanol injection, group II(n=3) 0.2cc ethanol, and group III(n=3) 0.3cc ethanol into the feline brains. In the microwave irradiation experiment, twelve male cats were divided into four groups including group I(n=3) irradiated with 30 watt electrical power with 10 sec duration, group II(n=3) same power with 30 sec duration, group III(n=3) irradiated with 60 watt power with 10 sec duration, and group IV irradiated with 60 watt power with 30 sec duration. MR images were obtained in both ethanol injection and microwave irradiation experiments. Pathologic examinations were done after completion of MR imagings. RESULTS: Contrast-enhanced T1-weighted MR images showing nodular or rim enhancement were most reliable in delineating the extent of the necrosis induced by ethanol injection and microwave irradiation. The contrast enhancement corresponded with gliosis in normal brain surrounding the necrotic area and hypervascularity in ongoing necrotic area and adjacent normal brain. There were various enhancement patterns after ethanol injection with reflux of ethanol. In case of microwave irradiation, round or oval enhancements were shown with clear margin. The size of the enhancement was well correlated with the amount of injected ethanol and the amount of electrical power. Application time was not correlated with the size of enhancement in high electrical power group. The feature of the edema after ethanol injection was unpredictable and predictable in case of microwave irradiation. CONCLUSION: It is easy to predict the result in case of microwave irradiation, and the achieved results can be used as basic information in performing these procedures.

Pseudo-Meigs Syndrome Due to Subserosal Leiomyoma Diagnosed by MR Imaging: Case Report

We report a case of pseudo-Meigs syndrome due to a large subserosal leiomyoma in a patient with a high serum carcinogenic antigen 125 level. Initial clinical examination suggested disseminated malignant disease though the typical signal characteristics of leiomyoma, seen at MR imaging, led to the diagnosis of pseudo-Meigs syndrome.

Clinical Utility and Role of Magnetic Resonance Cholangiography in the Evaluation of Choledocholithiasis Prior to Laparoscopic Cholecystectomy

PURPOSE: To compare the findings of MR cholangiography with those of ultrasound and biochemistry in patients with suspected choledocholithiasis, and to evaluate the clinical utility and role of MR cholangiography prior to laparoscopic cholecystectomy. MATERIALS AND METHODS: We retrospectively reviewed the radiologic findings and clinical records of 103 consecutive patients in whom choledocholithiasis was suspected and who underwent both ultrasound and MR cholangiography. For MR imaging, a 1.5T unit was used, and axial T1-FLASH, True FISP, and oblique coronal HASTE and RARE images were obtained. Initial biochemical values (AST, ALT, total bilirubin) were correlated with the findings of MR cholangiography. RESULTS: Choledocholithiasis was present in 36 of 103 patients: overall, there were 34 true-positive, 63 truenegative, four false-positive, and two false-negative results. In the detection of choledocholithiasis, MR cholangiography showed the following characteristics: sensitivity, 94%; specificity, 94%; positive predictive value, 89%; negative predictive value, 96%; accuracy, 95%. Calculi in the common bile duct were detected in 3 of 33 patients (9%) in whom ultrasound showed that the caliber of the common bile duct was normal and whose laboratory findings were normal, and in 12 of 43 (28%) of those whose common bile duct was dilatated or whose laboratory values were abnormal. Calculi were present in the common bile duct of 21 of 27 patients (78%) with abnormal laboratory values and abnormal ultrasound findings. CONCLUSION: Choledocholithiasis was detected in 25% of patients without clinical suspicion and was not present in 25% of patients with strong clinical suspicion. In patients with this condition, MR cholangiography is noninvasive and accurate, and we suggest that in patients with suspected choledocholithiasis, it should be a routine diagnostic procedure prior to laparoscopic cholecystectomy.

High Resolution MR Images from 3T Active-Shield Whole-Body MRI System

PURPOSE: Within a clinically acceptable time frame, we obtained the high resolution MR images of the human brain, knee, foot and wrist from 3T whole-body MRI system which was equipped with the world first 3T active shield magnet. MATERIALS AND METHODS: Spin echo (SE) and Fast Spin Echo (FSE) images were obtained from the human brain, knee, foot and wrist of normal subjects using a homemade birdcage and transverse electromagnetic (TEM) resonators operating in quadrature and tuned to 128 MHz. For acquisition of MR images of knee, foot and wrist, we employed a homemade saddle shaped RF coil. Typical common acquisition parameters were as follows: matrix= 512x512, field of view (FOV) = 20 cm, slice thickness = 3 mm, number of excitations (NEX) = 1. For T1-weighted MR images, we used TR= 500 ms, TE = 10 or 17.4 ms. For T2-weighted MR images, we used TR=4000 ms, TE = 108 ms. RESULTS: Signal to noise ratio (SNR) of 3T system was measured 2.7 times greater than that of prevalent 1.5T system. MR images obtained from 3T system revealed numerous small venous structures throughout the image plane and provided reasonable delineation between gray and white matter. CONCLUSION: The present results demonstrate that the MR images from 3T system could provide better diagnostic quality of resolution and sensitivity than those of 1.5T system. The elevated SNR observed in the 3T high field magnetic resonance imaging can be utilized to acquire images with a level of resolution approaching the microscopic structural level under in vivo conditions. These images represent a significant advance in our ability to examine small anatomical features with noninvasive imaging methods.

Spindle-Cell Carcinoma of Esophagus: A Case Report

Spindle-cell carcinoma of the esophagus is a rare malignant tumor composed of both carcinomatous and sarcomatous elements, and has generated many terminology problems. It is characterized by a bulky polypoid intraluminal mass with a lobulated surface located in the middle third of the esophagus. Local expansion of this organ is observed. The lesion may be pedunculated but despite its bulk, causes little obstruction. We report the imaging findings of a case of spindle-cell carcinoma arising in the upper esophagus.

Disturbed Functional Asymmetry of Sensorimotor Cortex in Schizophrenia: A Study with Functional Magnetic Resonance Imaging

PURPOSE: The purpose of this study was to investigate the pattern of cerebral response to motor tasks in patients with schizophrenia compared with normal subjects using functional MRI. MATERIALS AND METHODS: Nine right handed-schizophrenic patients and six right-handed normal subjects were included. We used right hand movement as task. Series of 120 consecutive echo-planar images per section were acquired during three cycles of task and rest activations. Lateralization index of cortical response was measured and compared between patients and normal subjects. RESULTS: Right hand motor task was associated with greater activation in left sensorimotor cortex than the right in normal subjects. Schizophrenia patients showed relatively decreased activation in left cortex and increased activation in right cortex compared with normal subjects. In one patient, reversed lateralization was noted. CONCLUSION: Normal hemispheric asymmetry of cortical response to motor task was found in different pattern in schizophrenia. Our result is consistent with functional disturbance of motor circuitry in this disorder. Functional MRI will play an important role in diagnosis and research of this disorder.

MR Imaging of Skeletal Muscle Injury in Rabbit: Comparison bet ween Diffusion and T2-weighted MR Images

PURPOSE: The purpose of this study was to apply the diffusion-weighted MR imaging technique to the early detection of skeletal muscle injury and to evaluate the usefulness of this imaging sequence. MATERIALS AND METHODS: Thirty rabbits, divided into two groups, were included in this study. Skeletal muscle injury was experimentally induced in the right thigh muscles of each rabbit by clamping with a hemostat for one minute. Four-stage clamping was applied to the rabbits in group I, but for group II there was only one stage. Diffusion and T2-weighted MR images were obtained using a 1.5T MR unit. Serial 5-and 30-minute, and 2-, 24-, and 48- hour delayed images were obtained after injury. The initial time of signal intensity change was recorded and the signal intensities of the injured sites and corresponding normal sites were measured and compared. RESULTS: On 5-minute delayed images in group I, diffusion-weighted MR images showed signal intensity changes in injured muscle in all 15 cases, but on T2-weighted images, change was not detected in three cases. In group II, 5-minute delayed T2-weighted images failed to depict the lesion in six cases, but on diffusion-weighted images, all lesions were detected. In addition, one lesion was not detected on 30-minute delayed T2- weighted images. In group II, the sensitivity of lesion detection was significantly higher on diffusion-weighted than on T2-weighted images (p = 0.0169). CONCLUSION: Diffusion-weighted MR imaging was shown to be more sensitive than T2-weighted imaging for the detection of signal intensity changes immediately after artificial injury, especially when this was of a lesser degree. These results suggest that diffusion-weighted MR imaging may be useful for the detection of early stage skeletal muscle injury.

Evaluation of Posterior Element Injury in Traumatic Thoraco-Lumbar Burst Fractures

PURPOSE: The purpose of this study is to examine the frequency of posterior element injury in patients with traumatic thoraco-lumbar burst fractures and to evaluate the correlation between the MR imaging and CT findings. MATERIALS AND METHODS: The MR images of 38 patients with 39 thoraco-lumbar burst fractures and the results of the CT examinations of 28 patients with 29 fractures were retrospectively analyzed. Both procedures were performed within two weeks of injury. Twenty-one males and 17 females were included ; their average age was 51.3 (range, 11-75) years. MR images were evaluated for injury to the posterior ligamentous complex, comprising the supraspinous ligament(SSL), the interspinous ligament(ISL), the flaval ligament(FL), and the capsule of facets. Analysis of the CT findings focused on the posterior bony elements of the lamina, pedicle, spinous process, and facet joint. RESULTS: MR imaging revealed posterior ligamentous injuries in 18(46.2%) of 39 burst fractures ; there was tearing of the ISL in 15 cases(38.5%), of the SSL in 11(28.2%), of the capsule of facets in 11(28.2%), and of the FL in nine(23.1%). Among the 29 burst fracture cases examined by CT, posterior bony injuries were detected in 13(44.8%). Lamina and facet joint fractures were detected in six cases(20.7%), facet separation or dislocation in six(20.7%), and spinous process and pedicle fracture in one(3.4%). In 29 burst fracture cases, both MRI and CT were performed. Among the 18 cases in which MR imaging revealed posterior ligamentous injuries, CT failed to demonstrate posterior element fractures in seven. On the other hand, among the 13 cases in which CT indicated posterior bony fractures, MR failed to reveal posterior ligamentous injuries in two. CONCLUSION: Posterior element injury is frequently found in patients with traumatic thoraco-lumbar burst fractures demonstrated by MR imaging(46.2%) and CT(44.8%). Both MRI and CT are useful tools for the evaluation of posterior element injury, which determines the degree of instability of traumatic burst fracture.