Advances in magnetic resonance imaging: applications in body imaging

Changes in the management of benign liver tumours: an analysis of 285 patients

OBJECTIVES

Benign liver tumours (BLTs) are common and their management remains controversial. This study assesses the safety of a selective management approach.

METHODS

Patients with BLT were identified from an institutional database. Patients with simple cysts or an incidental BLT in the setting of metastasis or concomitant malignancy were excluded.

RESULTS

A total of 285 patients presenting during the period from January 1992 to December 2009 with haemangioma (53.0%), focal nodular hyperplasia (23.9%), adenoma (10.2%) or indeterminate/other lesions (13.0%) were evaluated. Of these, 117 patients (41.1%) underwent immediate resection and 168 patients (58.9%) were followed with serial imaging (median follow-up: 30 months). During observation, eight patients (4.8%) underwent resection for tumour growth, inability to exclude malignancy or symptoms; no patients demonstrated malignant transformation or tumour-related complications. During the study period, the number of BLTs evaluated and the proportion of patients observed increased from 129 BLTs of which 36.4% were observed in 1992-2002 to 156 BLTs of which 71.2% were observed in 2003-2009 (P < 0.001). Diagnostic uncertainty led to resection in 29.5% of patients during the earlier period, but in only 13.4% during the more recent 7 years (P < 0.05).

CONCLUSIONS

Asymptomatic BLTs without concern for malignancy or adenoma can be safely observed with minimal risk for misdiagnosis. Patients selected for observation rarely require resection or develop tumour-related complications.

Recommendations for the outpatient surveillance of renal transplant recipients. American Society of Transplantation

Many complications after renal transplantation can be prevented if they are detected early. Guidelines have been developed for the prevention of diseases in the general population, but there are no comprehensive guidelines for the prevention of diseases and complications after renal transplantation. Therefore, the Clinical Practice Guidelines Committee of the American Society of Transplantation developed these guidelines to help physicians and other health care workers provide optimal care for renal transplant recipients. The guidelines are also intended to indirectly help patients receive the access to care that they need to ensure long-term allograft survival, by attempting to systematically define what that care encompasses. The guidelines are applicable to all adult and pediatric renal transplant recipients, and they cover the outpatient screening for and prevention of diseases and complications that commonly occur after renal transplantation. They do not cover the diagnosis and treatment of diseases and complications after they become manifest, and they do not cover the pretransplant evaluation of renal transplant candidates. The guidelines are comprehensive, but they do not pretend to cover every aspect of care. As much as possible, the guidelines are evidence-based, and each recommendation has been given a subjective grade to indicate the strength of evidence that supports the recommendation. It is hoped that these guidelines will provide a framework for additional discussion and research that will improve the care of renal transplant recipients.

Accuracy of pathologic techniques for the diagnosis of metastatic melanoma in sentinel lymph nodes

BACKGROUND

Sentinel lymph node (SLN) biopsy can accurately predict the presence of metastatic melanoma (MM) and has been used to identify patients with occult metastases. We present an analysis of the sensitivity and specificity of standard pathological techniques including intraoperative frozen section, permanent section, and immunohistochemistry in diagnosing MM within the SLN.

METHODS

Sixty-nine consecutive patients with primary malignant melanoma thickness of >1.0 mm or thinner lesions invading the reticular dermis (Clark level IV) who underwent SLN biopsy were reviewed. Lymph nodes were examined intraoperatively by frozen section (FS), permanent section (H&E), and by immunohistochemistry (IH) for S-100 protein and HMB45.

RESULTS

MM was found in 14 of 69 cases (20%). Permanent section H&E was performed in all cases, FS in 64 cases, and IH in 65 cases. FS analysis diagnosed MM in 4 of 14 cases (29%), was suspicious in 2 of 14 (14%), and falsely negative (FN) in 8 of 14 (57%) ultimately found to be positive with further workup. Within the FN group, MM was identified on review of the original FS slides in 3 of 8 cases (38%). Furthermore, within the FN group, the remaining 5 cases were identified as positive for MM by either permanent and/or deeper H&E sections and IH. IH alone with permanent H&E sections would have diagnosed MM in only 8 of 10 cases (80%) that were FS negative or suspicious. In no cases was MM identified by IH alone with the permanent and deeper H&E sections being negative. It is noteworthy that no false-positive cases were identified.

CONCLUSIONS

Intraoperative FS has low sensitivity in identifying MM within the SLN. IH alone does not increase the diagnostic yield. A combination of permanent H&E sections with deeper levels and S-100 and HMB45 IH dramatically increases the overall diagnostic sensitivity of SLN biopsy. Definitive diagnosis should await permanent H&E sections and IH staining.

Hepatic tumor imaging using iron oxide MRI: comparison with computed tomography, clinical impact, and cost analysis

BACKGROUND

The surgical management of hepatic tumors has traditionally relied on preoperative contrast-enhanced computed tomography (CECT) in combination with intraoperative ultrasonography (IOUS). Unfortunately, the ability to detect and characterize hepatic tumors by using CECT is limited, and IOUS frequently reveals additional disease that alters the operative approach. Recent advances in hepatic magnetic resonance imaging (MRI) may improve preoperative tumor detection and characterization; however, little is known about how MRI compares with CECT or about the clinical impact and cost considerations of liver MRI.

METHODS

A retrospective chart review was performed to compare iron oxide (Feridex [Fe])-MRI with CECT in the preoperative imaging of hepatic neoplasms, as well as to determine the clinical impact and overall healthcare costs associated with Fe-MRI.

RESULTS

Of approximately 1000 patients who underwent abdominal MRI at a single institution during a 20-month period, 57 were identified who underwent Fe-MRI evaluation of the liver. Indications for imaging included suspected metastases (n = 43), an indeterminate hepatic mass (n = 9), or primary hepatic cancer (n = 5). Overall, Fe-MRI identified a total of 157 lesions (mean, 2.75 per patient; range, 0-14). CECT was performed in 50 patients, of whom 35 had primary or metastatic cancer. Fe-MRI identified more lesions than CT (n = 136 vs. 77; P = .016), and the average size of lesion detected by Fe-MRI was significantly smaller than that by CECT (2.5 vs. 3.4 cm; P = .018). Comparison of CECT and Fe-MRI findings with IOUS and pathological specimens showed a significant difference in sensitivity (MRI, 86%; CECT, 58%; P<.001), and IOUS changed the operative approach in only 5% of those imaged with Fe-MRI. Overall, Fe-MRI altered the clinical management in 67% of patients imaged (n = 38 of 57), which corresponded to an overall net cost savings of $108,368 ($1,901 per patient).

CONCLUSIONS

Fe-MRI is a powerful imaging technique, with greater hepatic tumor detection sensitivity than CECT. Moreover, it is an economically feasible imaging method that will alter the clinical management in most patients imaged.