Imaging characteristics of papillary renal cell carcinoma by computed tomography scan and magnetic resonance imaging

AIM: To analyse the differences in the patterns between clear and papillary renal cell carcinomas using magnetic resonance imaging (MRI) and dual-phase helical computed tomography (CT). METHODS: We examined seven patients with papillary renal cell carcinoma, and six with clear cell carcinoma. The highest attenuation value of tumors in the corticomedullary phase (CMP) and the excretory phase (EP) was measured using the observer-defined region of interest (ROI). MRI consisted of T1-weighted and T2-weighted spin-echo imaging. RESULTS: All five tumors except for one with papillary renal cell carcinoma showed homogenous hypointensity, but all six tumors with clear cell carcinoma showed heterogeneous hyperintensity on their T2-weighted images. In the CMP, the mean CT numbers of the papillary renal cell carcinomas were significantly lower than those of the clear cell carcinomas. The mean enhancement of the papillary renal cell carcinomas in the CMP and the EP was significantly lower than that of the clear renal cell carcinomas. The mean CT numbers of the clear cell carcinomas in the CMP were markedly increased from those on the unenhanced CT; those in the EP were decreased gradually. But the mean CT numbers of the papillary renal cell carcinomas in the EP were still slightly more increased than those in the CMP. The enhancement patterns of the papillary renal cell carcinomas in the CMP and the EP were homogenous, but those of the clear cell carcinomas were heterogeneous. CONCLUSIONS: We can speculate the differential diagnosis from clear to papillary renal cell carcinoma using MRI and dual-phase helical CT.     

Assessment of resectability of esophageal cancer by computed tomography and magnetic resonance imaging

Sixty patients with esophageal cancer infiltration of mediastinal structures and metastasis to lymph nodes were prospectively evaluated by computed tomography and magnetic resonance imaging and then underwent surgical resection of the tumor (n = 57) or diagnostic thoracotomy (n = 3). Lymph nodes were excised from standardized locations and examined histologically. Sensitivity and specificity of both methods for all criteria were found so low that the value of these methods for planning surgery--or for stratification to different therapeutic arms in comparative studies--must be questioned.     

Staging of bladder carcinoma by magnetic resonance imaging compared with computed tomography and transurethral echography

Various techniques are used for tumor staging of bladder carcinoma such as endoscopic photography, transurethral echography, and computed tomographic (CT) scan. Endoscopic photography enables easy observation of tumor morphology, but we utilized other approaches to determine the presence or absence of tumor infiltration. Magnetic resonance imaging (MRI) has recently found widespread use in the staging of tumors. We first employed this approach at our hospital in February 1987. We compared the diagnostic accuracy rate of MRI with that of transurethral echography and CT scan in 10 cases of bladder tumor. The diagnostic accuracy rate of MRI was 70%, while that of transurethral echography and CT scan was 40% and 50%, respectively. We concluded that MRI was very useful in the diagnostic staging of bladder tumor.     

Differential diagnosis and staging of urological tumors by magnetic resonance imaging compared with computed tomography

Magnetic resonance imaging (MRI) was performed on 49 urological tumors (11 renal cell carcinomas, 3 renal pelvic cancers, 2 renal angiomyolipomas, 1 renal leiomyosarcoma, 1 large renal cyst, 4 adrenal tumors, 11 bladder cancers, 2 bone metastasis from bladder cancer, 10 prostatic cancers, 1 prostatic sarcoma, 1 urethral cancer, 1 penile cancer and 1 perivesical granuloma) since October 1985 to September 1986. MRI was performed using a Signa (G.E.) with a 1.5T superconductive magnet and 3 images, including T1 weighted image, T2 weighted image, and proton density image, were obtained. In conclusion MRI is a noninvasive examination and gives more information than computed tomography despite its high cost. In renal cell carcinoma, the chemical shift in MRI and clear visualization of tumor thrombus enable accurate staging. Differential diagnosis from other renal mass lesions may be possible by the T2 weighted image. In adrenal disease, most of the adrenal masses can be differentiated, but in some cases it is impossible. In bladder cancer, wall invasion of tumor may be evaluated in T2 weighted image, and MRI is suitable for staging of locally advanced tumor. In prostatic cancer, visualization of periprostatic plexus and differentiation between internal and external gland may enable local staging and identification of low stage tumors.     

Anaesthesia for magnetic resonance imaging/computed tomography

The need for general anaesthesia for magnetic resonance imaging/computed tomography investigations can be reduced by the implementation of structured sedation programmes supervised by anaesthetists. Despite its side-effects, chloral hydrate is still the drug most widely used. Rectal thiopental or intravenous propofol are suggested anaesthetic agents for pre-school children and uncooperative or claustrophobic individuals. Spiral computed tomography scans and ultrafast magnetic resonance imaging shorten immobilization times further. However, functional magnetic resonance imaging and intervention techniques in neuroradiology depend on a motionless patient. A useful strategy for testing anaesthesia equipment has been outlined.     

钡灌肠和CT及MRI对结直肠癌诊断的比较影像学研究

目的比较钡灌肠(BE)、计算机X线断层扫描(CT)和磁共振成像(MRI)对结直肠癌检查的临床价值。方法对64例经临床拟诊结直肠癌患者的影像学资料进行对比分析。结果64例患者中39例行BE检查,31例行螺旋CT检查,42例行MRI检查。其中经手术病理证实的结直肠癌54例。BE、CT和MRI对结直肠癌检查的敏感度分别为96.9%、96.2%和97.1%;准确度分别为92.3%、83.9%和90.5%。CT和MRI对结直肠癌T分期诊断的准确度分别为73.1%和82.9%。结论BE是结直肠癌的基本影像学检查方法,CT和MRI是BE必要的补充检查手段,BE加MRI是诊断结直肠癌的优选组合检查方法。     

Comparison of computed tomography and magnetic resonance imaging in the diagnosis of parotid tumors

OBJECTIVE: The role of computed tomography (CT) and magnetic resonance imaging (MRI) in the diagnosis of parotid tumors was investigated. METHODS: Forty patients with the clinical suspicion of a parotid mass underwent both CT and MRI of the parotid region. Two radiologists independently assessed the CT and MRI results with respect to tumor localization, tumor margin characteristics, and infiltration of surrounding tissue. Histopathologic specimens were obtained in all cases and correlated with the radiologic findings. RESULTS: The sensitivity and specificity of CT and MRI were nearly the same for tumor location, tumor margin, and tumor infiltration. CONCLUSION: The 2 imaging techniques provided the same information with respect to the presurgical planning and contribute to the diagnosis and therapy planning of parotid tumors.     

Contrast enhanced computed tomography and magnetic resonance imaging in the diagnosis of recurrent disc herniation

Summary A positive result of re-operation in patients with recurrent symptoms after lumbar disc surgery is likely only if a new disc herniation is present. An improved ability to differentiate between recurrent disc herniation and scar tissue by contrast enhanced CT and MRI is suggested in earlier studies.In a prospective study 29 patients were selected for operation for suspected recurrent disc herniation. The inclusion of the patients was based on clinical symptoms and signs and myelography or non-enhanced CT. All patients were examined by CT and MRI both with and without intravenous contrast pre-operatively. The examinations were evaluated blind on a five point scale and statistical analysed by a regret function.Intravenous contrast improved the diagnostic power of both CT and MRI. MRI was superior to CT in both non-enhanced and enhanced examinations. MRI with intravenous contrast enhancement is proposed as the primary examination in patients with suspected recurrent disc herniation.     

Comparative morphological study of the pituitary gland by computed tomography and magnetic resonance imaging

A prospective study was undertaken to compare the morphology of the pituitary gland by computed tomography (CT) and magnetic resonance imaging (MRI) in 27 consecutive patients. CT is an accepted imaging modality but this study suggested that MRI has certain advantages. MRI is proposed as the imaging modality of choice for lesions of the pituitary gland.     

自身免疫性胰腺炎的CT和MRI的影像学表现

目的探讨自身免疫性胰腺炎CT和MRI的影像学特点,提高对自身免疫性胰腺炎的认识和影像学诊断水平。方法回顾性分析45例经激素治疗或手术病理证实的自身免疫性胰腺炎患者的CT和MRI影像学资料,观察胰腺及周围组织、胰管和胆管的影像学表现,总结自身免疫性胰腺炎CT和MRI的影像学特点。结果 45例自身免疫性胰腺炎患者中,男性32例,女性13例,其中37例患者表现为胰腺的弥漫性肿大,8例患者表现为胰腺局限性肿大,CT检查中有27例患者的胰腺病灶平扫密度减低;MRI检查中有16例患者胰腺病灶出现信号的改变,表现为T1WI上低信号,T2WI上稍高信号;45例患者胰腺病灶均表现为延迟强化方式改变。10例患者的CT和7例患者的MRI表现为胰管狭窄,2例患者的CT和1例的患者MRI表现为胆总管狭窄。14例患者的CT及MRI表现胰腺周围的"假包膜"征象。结论自身免疫性胰腺炎在CT和MRI上具有一定的影像学特点,结合实验室相关检查有助于该疾病的诊断。     

Renal cell carcinoma: magnetic resonance imaging and computerized tomography

Summary Surgical data of eight patients who underwent nephrectomy for renal cell carcinoma were compared with the findings of magnetic resonance imaging (MRI) and, in five of these, with those of computerized tomography (CT) as well. In another three patients, only CT and MRI were available, since the presence of metastases precluded surgery. In general, MRI and CT accurately displayed local tumor extension, whereas magnetic resonance was superior to computed tomography in demonstrating tumor involvement of large venous structures.     

Prenatal diagnosis of esophageal atresia using sonography and magnetic resonance imaging

BACKGROUND: The diagnosis of esophageal atresia may be suspected on prenatal ultrasound scan in fetuses with a small or absent stomach or unexplained polyhydramnios. However, these findings are thought to have a low positive predictive value and clinical decisions affecting timing or site of delivery may be made erroneously. The authors evaluated the accuracy of fetal sonography followed by magnetic resonance imaging (MRI) for the diagnosis of this lesion. METHODS: Fetuses considered to be at risk for esophageal atresia based on detailed obstetric sonography underwent fetal MRI using a single-shot rapid-acquisition technique, and the T(2)-weighted images were evaluated prospectively. Scans were considered to be positive if the proximal esophagus was dilated, and the distal esophagus was not seen and negative if the esophagus was visualized throughout its length. RESULTS: Ten fetuses underwent MRI scanning. All had a small or absent stomach bubble with unexplained polyhydramnios. Four scans were considered to be negative for esophageal atresia; all 4 were found to have a normal esophagus after delivery. Six scans were considered to be positive; 5 had esophageal atresia (2 with tracheoesophageal fistula and 3 without), and one had a neurologic syndrome with a normal esophagus. CONCLUSIONS: Magnetic resonance imaging appears to be accurate for establishing or ruling out a prenatal diagnosis of esophageal atresia, and should be considered in fetuses who are at high risk based on ultrasound findings.     

Femoral head osteonecrosis. Detection by magnetic resonance imaging versus single-photon emission computed tomography

Magnetic resonance imaging (MRI) and single-photon emission computed tomography (SPECT) examinations were compared for detection of femoral head osteonecrosis. Of 29 hips with clinical and roentgenographic evidence of osteonecrosis (18 histologically confirmed), 15 were Stage II, three transitional, six Stage III, and five Stage IV. MRI identified osteonecrosis in all 29 cases (100% sensitivity), and there were no false-positives (100% specificity). Of 24 osteonecrotic hips with technically adequate examinations, SPECT identified 14 (sensitivity 58%), and there were four false-positives (78% specificity). If Stages III and IV were eliminated, SPECT correctly identified ten of 15 (67% sensitivity).     

Comparison of nuclear magnetic resonance imaging and computed tomography in the diagnosis of upper cervical spinal cord compression

Because of its ability to visualize soft-tissue structures in greater detail than any previous radiographic modality, nuclear magnetic resonance (NMR) has been heralded as one of the greatest advances in recent years. It is particularly well suited in diagnosis of spinal disorders since it can visualize the spinal cord and cerebrospinal fluid without intrathecal contrast agents. This is a preliminary report of our experience of NMR examination in 106 patients studied since November 1982 at Case Western Reserve University Hospital. One of the best applications of NMR is for compressive lesions of the upper cervical spine because "functional" images can be obtained. The information from NMR was compared with computed tomography (CT) in 14 patients with various etiologies of neural compression--atlanto-occipital subluxation in Down's syndrome, fixed post-traumatic atlantoaxial subluxation, rheumatoid atlantoaxial subluxation and basilar impression of the odontoid, ossification of the posterior longitudinal ligament, Klippel-Feil syndrome, congenital spinal stenosis, cervical spondylosis, Arnold-Chiari malformation, etc. Unlike CT, NMR can directly image in the sagittal plane without computer reformatting of axial cuts. This readily provides direct images of the spinal cord in neutral, flexion, and extension to show the mechanism of neural compression. Disadvantages of NMR compared with CT include poorer image resolution, slightly increased imaging time, and no patients with intracranial aneurysm clips or cardiac pacemakers can be studied. Advantages include no radiation exposure, no intrathecal contrast agent is required to differentiate CSF from neural tissue, and direct sagittal, coronal, and oblique images can be obtained. As a result of this preliminary experience, computed tomography and nuclear magnetic resonance imaging appear to be complimentary studies--CT provides better osseous detail, whereas NMR offers superior soft tissue resolution.     

Comparative evaluation of intracranial epidermoid tumors with computed tomography and magnetic resonance imaging

The diagnosis of intracranial epidermoid tumors with computed tomography (CT) is often difficult because of indistinct margins, close proximity to the skull base, and a density similar to that of cerebrospinal fluid (CSF). Recent experience with six histologically confirmed epidermoid tumors served to emphasize the value of magnetic resonance (MR) imaging in studying these lesions. MR images were obtained using varying spin echo and inversion recovery techniques with a 0.5-tesla superconducting magnet. CT with and without enhancement had been performed in each case. In Case 1, CT showed an ill-defined left cerebellopontine angle hypodensity. MR imaging clearly showed the presence of abnormal tissue at that location. Case 2 showed a CSF density mass in the right upper posterior fossa. MR imaging of that area showed a variegated signal of a mass extending supratentorially. CT of Case 3 showed a left medial middle fossa hypodensity with an enhancing rim. MR imaging showed a clearly extraaxial mass in that location. In Case 4, a diffuse cerebellar hemispheric hypodensity was observed on CT and was clearly demarcated by MR studies. A huge lesion, thought initially to be an arachnoid cyst on CT of Case 5, was seen on MR imaging to be a large, extraventricular mass displacing the temporal lobe. Finally, CT in Case 6 was suggestive of a poorly demarcated right cerebellopontine angle lesion, which was seen on MR images to be extraaxial, displacing the brain stem. Various MR images more clearly demonstrate the extent of abnormal tissue than CT of epidermoid tumors.(ABSTRACT TRUNCATED AT 250 WORDS)     

Discrepancy between computed tomography and magnetic resonance imaging in a case of medulloblastoma

In a 2-year-old girl with signs and symptoms of a posterior fossa tumor, the computed tomographic scan showed what appeared to be a brain stem glioma. However, magnetic resonance imaging (MRI) demonstrated the lesion to be extrinsic to the brain stem. Posterior fossa exploration disclosed a medulloblastoma filling the 4th ventricle. This discrepancy in imaging techniques points out the usefulness of MRI in the evaluation and treatment of posterior fossa lesions.     

A prospective comparison between multidetector-row computed tomography and magnetic resonance imaging in the preoperative evaluation of rectal carcinoma

BACKGROUND: Multidetector-row computed tomography (MDCT, or multislice CT) is a new modality with four detectors, which makes examination time shorter and produces higher resolution and multiplanar reformation of the images. Its diagnostic role in patients with rectal carcinoma has not been determined. METHODS: Twenty-one patients with rectal carcinoma were preoperatively examined by both MDCT and magnetic resonance imaging (MRI). Diagnostic accuracies of both modalities were compared regarding depth of tumor invasion and lymph node metastasis based on the pathologic findings. RESULTS: Both examinations detected all tumors. Regarding depth of tumor invasion, the concordance was 95.2% (20 of 21) for MDCT and 100% (21 of 21) for MRI. Regarding lymph node metastasis, the overall accuracy was 61.9% for MDCT and 70.0% for MRI. CONCLUSIONS: Multidetector-row computed tomography was equal to MRI in the preoperative local staging of rectal carcinoma.