Magnetic resonance imaging in potential postsurgical recurrence of breast cancer: pitfalls and limitations.

OBJECTIVE: To determine the sensitivity and specificity of magnetic resonance imaging (MRI) of the breast for detecting recurrent carcinoma. PATIENTS AND METHODS: Thirteen patients ranging in age from 47 to 77 years who had undergone lumpectomy 5 months to 8 years earlier and who had mammographic findings suggestive of recurrence underwent contrast-enhanced dynamic MRI. Histologic confirmation was obtained in all cases. RESULTS: Of the eight lesions (in seven patients) for which biopsy proved recurrence, MRI correctly identified six; there were two false negative results. Of the six benign lesions, four were correctly identified by MRI. The two false positive results involved fat necrosis and a foreign-body reaction respectively. CONCLUSION: These results confirm previous reports of the poor specificity of MRI of focal breast lesions. The authors therefore recommend caution in the use of breast MRI in the assessment and management of suspected recurrent carcinoma.

Anal wall thickness under normal and inflammatory conditions of the anorectum as determined by endoluminal ultrasonography.

OBJECTIVES: To determine the normal dimensions of the anal wall and if there were detectable differences in inflammatory disorders. METHODS: A cross-sectional survey was performed on all patients referred to a university anorectal ultrasound clinic who had either perianal Crohn's disease (17 patients), ileoanal pouches (15 patients), perianal fistula (15 patients), or previous radiation to the rectum (5 patients). Results were compared to 40 normal controls. Anal wall thickness (AWT), mucosa, submucosa, internal sphincter thickness (MSIT), and external sphincter thickness (EST) were measured or calculated. Intra- and interobserver reliability was assessed. RESULTS: The mean AWT was 14.8 mm (95% CI: 14.0-15.6), mean EST was 8.3 mm (95% CI: 7.6-9.0), and the mean MSIT was 6.5 mm (95% CI: 5.8-7.2) in the control subjects. Measurements did not differ significantly with sex or with an increase in age. Patients with perianal Crohn's disease, ileoanal pouches with septic complications, and previous local radiotherapy had significant increases in anal wall thickness. In Crohn's disease, the significant increase was in MSIT, whereas, in the pouch patients, the increase was in the EST. Reliability studies demonstrated a learning curve with experience and a better correlation with determination of AWT than MSIT. CONCLUSIONS: Patients with anorectal inflammatory conditions have increased thickness in anal wall dimensions.

Reliability and validity studies of endoluminal ultrasonography for anorectal disorders.

PURPOSE: Endoluminal ultrasonography (ELUS) is accurate in the assessment of penetration through the rectal wall by carcinoma. Clinical studies were performed to determine the reliability and validity of ELUS. METHODS: The interobserver reliability among four observers with varying experience with ELUS was determined for staging the penetration of rectal cancer through the rectal wall. The ability of ELUS to change the clinical management of the referring clinician (comprehensiveness) was assessed on all referrals over a six-month period. RESULTS: The reliability of ELUS for staging rectal cancer demonstrated only fair to moderate correlation (weighted kappa range, 0.22-0.47). The accuracy of ELUS compared with surgical pathology demonstrated a learning curve proportional to the experience of the observer. In 45 percent of referrals, ELUS changed the clinical management of patients and in 76 percent of referrals the clinician's confidence in the diagnosis and management of patients was altered. ELUS was more likely to change the management of patients with pelvic pouch sepsis (70 percent) and early neoplastic lesions (57 percent) than in more advanced neoplastic lesions (40 percent), perianal Crohn's disease (40 percent), complex noninflammatory bowel disease sepsis (33 percent), and incontinence (31 percent). CONCLUSIONS: ELUS has the ability to change the clinical management of a variety of anorectal conditions. However, for neoplasia the interobserver reliability is only moderate and a learning curve exists.

Pediatric cerebrovascular disease. Alterations of regional cerebral blood flow detected by TC 99m-HMPAO SPECT.

Regional cerebral blood flow (rCBF) alterations, as determined by single photon emission computed tomography (SPECT) using technetium Tc 99m hexamethyl propylenamine oxime (Tc 99m-HM-PAO), were studied in 15 infants and children presenting with cerebrovascular disorders between the ages of 2 weeks and 16 years. The rCBF patterns were correlated with clinical presentation, electroencephalographic patterns, radiologic studies, including computed tomography and magnetic resonance imaging of the head, and cerebral angiography. All patients presented with motor weakness that was accompanied in some with dysphasia, defects in visual fields, obtundation, seizures, and high temperature. Perturbations of rCBF with Tc 99m-HMPAO SPECT brain scanning were detected in all patients investigated, with no adverse effects related to the radiotracer. All patients had a focal area of decreased rCBF, with adjacent hyperemia in 3 patients. In 7 patients, there was an rCBF decrease in a vascular distribution, mainly that of the middle cerebral artery, that correlated with the clinical findings and a focal electroencephalogram, as well as computed tomography and magnetic resonance imaging of the head. Impairment of rCBF was more extensive in 3 children, while early abnormal SPECT findings preceded abnormal computed tomographic findings in another 2 children. In 2 patients, Tc 99m-HMPAO SPECT was the only positive radiologic test to correlate with focal clinical and electroencephalographic abnormalities, in view of repeated normal computed tomographic scans. We conclude that Tc 99m-HMPAO SPECT brain scanning is a sensitive, complementary diagnostic measure in the early detection, localization, and estimation of rCBF alterations in pediatric cerebrovascular disease.

Role of MRI bone marrow imaging in recurrent lymphoma.

Infiltration by Hodgkin disease of the bone marrow of a thoracic vertebral body in a symptomatic patient was identified by magnetic resonance imaging, but not by radiography, radionuclide bone scanning, or computed tomography. The discovery of disease at this site substantially altered subsequent therapy.

Prostatic carcinoma and benign prostatic hyperplasia: correlation of high-resolution MR and histopathologic findings.

High-resolution magnetic resonance (MR) imaging of 24 fresh radical prostatectomy specimens was performed on an experimental 1.9-T system. Direct correlation between the findings in 7-micron-thick macrosections and their corresponding MR images was possible. Fourteen patients had macroscopic evidence of cancer. In all 14 cases, the carcinoma nodules appeared as areas of low signal intensity on images obtained with a repetition time of 2,500 msec and an echo time of 80 msec. Ten of 14 nodules had well-defined margins and consisted of densely packed glandular elements, which displaced the surrounding normal glandular material of higher signal intensity. Ten specimens displayed benign prostatic hyperplasia (BPH). The MR characteristics of this entity were quite variable but relatively predictable, depending on the distribution and size of the glandular elements, as well as the composition of the surrounding stroma. In BPH, the changes began in the central portion of the gland. The areas of highest signal intensity corresponded to dilated glandular elements (cystic ectasia), while the areas of lowest signal intensity corresponded to collagen (scar) and fibromuscular stroma. Nodules of mixed glandular BPH and fibromuscular BPH were found to have signal intensities similar to those of well-differentiated nodules of prostatic adenocarcinoma.

Avascular necrosis versus other diseases of the hip: sensitivity of MR imaging.

Magnetic resonance (MR) imaging of the hip has been useful in the examination of patients for the presence of avascular necrosis (AVN). In the detection of AVN, MR imaging is more sensitive than computed tomography or nuclear scintigraphy. This study assessed the usefulness of MR imaging in the differentiation of AVN from other hip diseases. Twenty-two cases of non-AVN hip disease were matched with 23 biopsy-proved cases of AVN and ten normal controls. MR images were rated in a blinded manner by five experienced radiologists, and receiver operating characteristic (ROC) analysis was performed on the data. In the discrimination of AVN from other hip diseases or from normality, the A(z) value (the area under the ROC curve) was 98.6. With a specificity of 98%, MR imaging was 97% sensitive in the differentiation of AVN from normality, 85% sensitive in the differentiation of AVN from non-AVN disease, and 91% sensitive in the differentiation of AVN from both conditions. MR imaging may therefore help discriminate between AVN and other hip diseases.

Radiographically negative avascular necrosis: detection with MR imaging.

To correlate the morphologic appearance on magnetic resonance (MR) images of radiographically negative avascular necrosis (AVN) of the femoral head with that on computed tomographic (CT) and radionuclide scans, the radiographic and clinical records of 24 patients were reviewed retrospectively. In 18 patients the MR signal intensity features were monitored by means of serial imaging. All MR studies included T1-weighted (short repetition time [TR], short echo delay time [TE] ) imaging and T2-weighted imaging (long TR, long TE). Thirty-one hips were determined with MR to be involved by AVN; 27 were staged on the basis of signal intensity characteristics within the low-intensity rim. Core decompression was performed on 18 hips. Afterward, progression of disease occurred in only one hip. Fourteen of the 16 asymptomatic patients (88%) had early-stage focal lesions. CT scans were obtained in 15 patients and radionuclide scans in 21. Ten hips at radionuclide imaging and five at CT appeared normal when MR results were distinctly abnormal. MR can depict early radiographically negative AVN in asymptomatic individuals. At this early stage, the lesions in this series appear to be nonprogressive after treatment.

MR imaging of soft-tissue hemangiomas: correlation with pathologic findings.

Soft-tissue hemangiomas have been described in MR imaging, but a histopathologic correlation to better understand the MR appearance has not been reported. Five patients with intramuscular soft-tissue hemangiomas were imaged in orthogonal planes on a 1.5-T system with spin-echo (SE) short-TR/TE sequences (600/20) and long-TR/TE sequences (2500/20-80). Complete intact surgical specimens were obtained, and gross and histopathologic findings were compared with MR findings. A striated-septated configuration with a high signal intensity on long-SE sequences (TE greater than 75 msec) correlated with endothelial-lined vascular channels separated by fibrous and/or fatty linear strands. An awareness of the morphologic MR pattern of soft-tissue hemangiomas may aid in recognition of these lesions.

Hyaline cartilage-origin bone and soft-tissue neoplasms: MR appearance and histologic correlation.

Magnetic resonance (MR) images and histologic studies of 16 chondroid-matrix lesions were reviewed to determine if any distinctive morphologic or signal features might be discerned. Ten biopsy-proved nonchondroid bone lesions were compared in terms of configuration and signal characteristics. The tumor matrix had a distinctive appearance of homogeneous high signal intensity in a defined lobular configuration on images of all hyaline cartilage lesions obtained with a long repetition time and a long echo time. The areas of hyperintensity relative to muscle corresponded to areas of hyaline cartilage matrix with its uniform composition, low cellularity, and high water content; the lobular morphologic characteristic had an identical histologic correlate. The chondroblastomas, clear-cell chondrosarcoma, and synovial chondromatosis demonstrated a much more cellular stroma, with only scattered islands of chondroid matrix, and were isointense or hypointense compared with muscle on all MR sequences. The distinctive lobular, high-intensity MR appearance was not seen in the ten nonchondroid bone lesions.

Strategies for musculoskeletal magnetic resonance imaging.

There is a broad range of clinical applications for MRI in the diagnosis of musculoskeletal disease, and the emphasis in this article is on the evaluation of the joints and extremities. A discussion of basic principles, including radiofrequency coils, positioning, pulsing sequences, imaging planes, and technical parameters is followed by discussions of tailored approaches to the evaluation of mass lesions and joint pathology for specific regions of the musculoskeletal system. In the final section, consideration is given to the overall role of MRI in the diagnosis of musculoskeletal disorders with respect to other established imaging modalities.

Meniscal and ganglion cysts of the knee: MR evaluation.

Meniscal and ganglion cysts frequently present as palpable masses of the knee but occur at different locations than do popliteal cysts. Meniscal cysts also may be discovered incidentally on studies performed for suspected internal derangement. Sixteen cystic lesions of the knee were evaluated with MR, including 11 meniscal cysts and five ganglion cysts. Scans were performed at 1.5 T by using a transmit/receive extremity coil or a receive-only surface coil. Standard spin-echo imaging, including at least one long-TR/asymmetric-TE sequence, was performed in all cases. In six patients, gradient-echo, reduced flip-angle sequences also were done. All meniscal cysts (but none of the ganglion cysts) were associated with horizontal meniscal tears. Cysts were visualized best on the long-TR/TE images; meniscal tears were seen best on the short-TR/TE and long-TR/short-TE images. Meniscal tears and cysts were also seen well on the fast-scanning sequences. Septations were noted in four meniscal cysts and in four ganglion cysts on the long-TR/TE images. Long-TR/TE images were also useful in showing the relationship between the cyst and joint capsule in three of the ganglion cysts. MR imaging is an effective, noninvasive method for evaluating cystic lesions of the knee. Meniscal cysts are always associated with underlying horizontal meniscal tears, which can be detected with MR. Ganglion cysts are not associated with meniscal tears, but may have connections to the joint capsule, which can be detected with MR.

Tumor recurrence versus fibrosis in the female pelvis: differentiation with MR imaging at 1.5 T.

Twenty-two women with previous malignancies of the pelvis were examined with magnetic resonance (MR) imaging. In 21 of 22 patients, the MR imaging findings were confirmed with laparotomy on transvaginal biopsy. Twelve of the 22 patients had recurrent tumors; ten had a localized fibrotic mass, and two were found to have coexistent local fibrotic masses and distant recurrence. In 11 of the 12 patients with recurrence, MR imaging demonstrated the recurrent tumor as an area of increased signal intensity on long repetition time, long echo time spin-echo pulse sequences. Signal intensity of localized fibrosis varied with the time since initial treatment. Separate signal intensity measurements for T1- and T2-weighted images were obtained in regions of interest in recurrent tumors, early fibrosis (1-6 months after first treatment), and late fibrosis (more than 12 months). Ratios of signal intensity of muscle to that of fat were calculated, and a statistical analysis (Student t test) was performed. On heavily T2-weighted pulse sequences, the differences in signal intensity between late fibrosis and recurrent tumors were statistically significant (P less than .001). MR imaging is useful in identifying recurrent pelvic neoplasm and distinguishing it from posttreatment fibrosis.

Focal adrenal hemorrhage: a new US appearance.

The ultrasonographic (US) appearance of neonatal adrenal hemorrhage has been described as a mass obliterating the normal contour of the entire gland. In the four cases described, different US appearances were found: In three, the hemorrhage was focal with the uninvolved portion of the gland visualized adjacent to the hemorrhage; in the fourth patient, hemorrhage involved primarily the medulla. Excellent computed tomographic or pathologic correlation with the US appearance was demonstrated. These findings suggest that adrenal hemorrhage should be considered in the differential diagnosis of focal adrenal masses in the neonate.