A prospective evaluation of postural stimulation testing, computed tomography and adrenal vein sampling in the differential diagnosis of primary aldosteronism.

CONTEXT: In primary aldosteronism (PA), discriminating unilateral from bilateral disease is crucial because adrenalectomy is frequently curative in the former case but rarely helps in the latter. Various series have reported the utility of postural stimulation testing (PST), cross-sectional imaging and adrenal vein sampling (AVS) in the assessment of PA, but most of these studies were retrospective. OBJECTIVE: To prospectively determine the diagnostic utility of PST, AVS and computed tomography (CT) using a radiological scoring system in the assessment of PA in a tertiary centre, as well as to document the incidence of autonomous cortisol cosecretion. DESIGN AND SETTING: Fifty consecutive patients with PA underwent PST, CT, AVS and a low-dose dexamethasone suppression test with measurement of serum cortisol at 48 h. For patients who underwent surgery, histological confirmation, and a normal postoperative serum aldosterone concentration and plasma renin activity were taken as evidence for unilateral disease. For other patients, results from successful adrenal vein sampling were the diagnostic evidence against which CT and PST were assessed. RESULTS: Postural stimulation testing had a sensitivity and specificity of 44-56% and 71-75%, respectively. CT had an overall sensitivity and specificity of 77% and 80%, respectively, rising to 100% sensitivity and specificity if there was a single, discrete macronodule with an unequivocally normal contralateral gland. Evidence of cosecretion of cortisol occurred in 14% of patients. CONCLUSIONS: Preliminary experience is presented of an objective radiological scoring system for selecting patients with PA for AVS. PST provides little, if any, useful additional information. A significant minority of patients with PA exhibit evidence of cortisol cosecretion, which may have implications for perioperative management.

Adrenocortical carcinoma: the range of appearances on CT and MRI.

OBJECTIVE: Adrenocortical carcinoma (ACC) is a rare, aggressive tumor arising from the adrenal cortex that typically presents late with a large mass. The increased use of cross-sectional imaging for unrelated reasons has led to a greater number of ACCs being detected incidentally at an earlier stage. Recognition of the typical clinical, biochemical, and imaging findings is imperative for rapid diagnosis, prompt intervention, and early use of the appropriate therapy. CONCLUSION: Cross-sectional imaging with CT and MRI is essential for determining the extent of local and distant tumor spread. Complete surgical resection is currently the only potentially curative treatment of ACC, and the information attained from CT and MRI is important to guide surgery and further patient management.

MRI appearances of uterine malignant mixed müllerian tumors.

OBJECTIVE: Uterine malignant mixed müllerian tumors (MMMTs) are rare aggressive tumors with a high incidence of lymphatic, peritoneal, and pulmonary metastases. Preoperative differentiation from endometrial adenocarcinoma would be beneficial because their prognoses differ. MATERIALS AND METHODS: We retrospectively reviewed MRI examinations of 51 histologically confirmed MMMTs. Tumor size, growth pattern, and imaging characteristics were recorded. Data were compared with MRI appearances of 73 endometrial adenocarcinomas. RESULTS: On T1-weighted images, MMMTs were predominantly isointense to myometrium (76%) and endometrium (71%), with heterogeneous texture in 33% of cases and hyperintense foci in 27% of cases. On T2-weighted images, 92% of MMMTs were hyperintense to myometrium and either hypointense (55%) or isointense (41%) to endometrium. In 12% of cases, large heterogeneous MMMTs obliterated uterine architecture and were aggressive in appearance, whereas in 88% of cases, the appearances were indistinguishable from those of endometrial adenocarcinoma. Significantly more MMMTs than endometrial adenocarcinomas had cervical invasion (p = 0.008) and nodal enlargement (p = 0.00008). Dynamic contrast-enhanced images (available for 19 of 51 patients) obtained at less than 1 minute after administration of contrast agent showed MMMT enhancement to be hypointense (42%; 5/12 patients) or isointense (33%; 4/12 patients) to myometrium; between 1 and 4 minutes after administration of contrast agent, tumors were hypointense (58%; 7/12 patients); and at more than 4 minutes after administration of contrast agent (n = 18), MMMTs were isointense in 56% of cases. This finding is significantly different from that for endometrial adenocarcinoma, where enhancement is less than that of myometrium in 90% of cases (p = 4 × 10⁻8). CONCLUSION: MMMTs do not have a pathognomonic MRI appearance. However, radiologic suspicion should increase in the presence of large heterogeneous infiltrative tumors or when tumoral enhancement equals or exceeds that of myometrium.

Perforation of a malignant ovarian tumor into the recto-sigmoid colon.

Ovarian cancer often presents at an advanced stage, but tends to be an intra-peritoneal disease that respects peritoneal planes. Thus, colo-rectal perforation of the tumor is an extremely rare presentation. The surgical treatment of malignant colo-ovarian fistula should include complete cyto-reduction at the same time as the treatment of the fistula. However, prognosis remains poor, because of the advanced stage of neoplasia. We report the case of a patient with an ovarian malignant tumor perforating into the recto-sigmoid colon. CT scan was the cornerstone of the radiological diagnosis. We managed to perform a complete cyto-reduction, including an en-bloc resection of the uterus, the mass, adnexa and recto-sigmoid with removal of the associated pelvic abscess.

Contrasting clinical manifestations of SDHB and VHL associated chromaffin tumours.

Mutations in succinate dehydrogense-B (SDHB) and the von Hippel-Lindau (VHL) genes result in an increased risk of developing chromaffin tumours via a common aetiological pathway. The aim of the present retrospective study was to compare the clinical phenotypes of disease in subjects developing chromaffin tumours as a result of SDHB mutations or VHL disease. Thirty-one subjects with chromaffin tumours were assessed; 16 subjects had SDHB gene mutations and 15 subjects had a diagnosis of VHL. VHL-related tumours were predominantly adrenal phaeochromocytomas (22/26; 84.6%), while SDHB-related tumours were predominantly extra-adrenal paragangliomas (19/25; 76%). Median age at onset of the first chromaffin tumour was similar in the two cohorts. Tumour size was significantly larger in the SDHB cohort in comparison with the VHL cohort (P=0.002). Multifocal disease was present in 9/15 (60%) of the VHL cohort (bilateral phaeochromocytomas) and only 3/16 (19%) of the SDHB cohort, while metastatic disease was found in 5/16 (31%) of the SDHB cohort but not in the VHL cohort to date. The frequency of symptoms, hypertension and the magnitude of catecholamine secretion appeared to be greater in the SDHB cohort. Renal cell carcinomas were a feature in 5/15 (33%) of the VHL cohort and 1/16 (6%) of the SDHB cohort. These data indicate that SDHB-related tumours are predominantly extra-adrenal in location and associated with higher catecholamine secretion and more malignant disease, in subjects who appear more symptomatic. VHL-related tumours tend to be adrenal phaeochromocytomas, frequently bilateral and associated with a milder phenotype.

Imaging in covert ectopic ACTH secretion: a CT pictorial review.

The syndrome of ectopic adrenocorticotrophin secretion (EAS) is rare and is due to excess adrenocorticotrophin (ACTH) production from a nonpituitary tumour. These tumours can be covert, where the tumours are not readily apparent, and very small making them challenging to image. It is clinically and biochemically difficult to distinguish between covert EAS and Cushing's disease. The first-line investigation in locating the source of ACTH production is computed tomography (CT). The aim of this pictorial review is to illustrate the likely covert sites and related imaging findings. We review the CT appearances of tumours resulting in covert EAS and the associated literature. The most common tumours were bronchial carcinoid tumours, which appear as small, well-defined, round or ovoid pulmonary lesions. Rarer causes included thymic carcinoids, gastrointestinal carcinoids and pancreatic neuroendocrine tumours. Awareness of the imaging characteristics will aid identification of the source of ACTH production and allow potentially curative surgical resection.

Pearls and pitfalls of MR lymphography in gynecologic malignancy.

Dissemination of tumor to lymph nodes is one of the principal routes of metastatic disease. The presence or absence of nodal disease is an important prognostic factor in gynecologic malignancies; thus, nodal staging is an integral part of the pretreatment assessment. It is vital that pretreatment nodal staging be accurate and reliable. Current imaging techniques such as computed tomography and magnetic resonance (MR) imaging have limitations because they rely almost exclusively on size criteria. MR lymphography uses a lymph node-specific contrast agent (ferumoxtran-10) composed of ultrasmall superparamagnetic iron oxide particles. The contrast agent is taken up by macrophages within benign lymph nodes and allows differentiation from malignant nodes on the basis of alterations in signal intensity. This technique has been shown to increase the sensitivity and specificity of detection of lymph node metastases independent of nodal size. However, as with any technique, there are pitfalls that the radiologist must be aware of to avoid interpretative errors.

Fistulas in malignant gynecologic disease: etiology, imaging, and management.

A fistula that occurs in association with a malignancy of the female reproductive tract may be caused by a primary or recurrent tumor or may be a complication of surgery or radiation therapy. Identification of the cause, complexity, and location of a fistula is essential for optimal management planning. Radiologic imaging, particularly with computed tomography and magnetic resonance techniques, is invaluable for the assessment of gynecologic fistulas and may help direct the clinician toward the most appropriate management pathway. The modality and technique selected for the initial imaging evaluation depend largely on the clinical history and manifestations. However, imaging with a combination of techniques often is required for accurate diagnosis and effective treatment planning. Radiologists should be familiar with suggestive clinical signs and symptoms as well as with the characteristic appearances of rectovaginal, vesicovaginal, ureterovaginal, enterovesical, enterocutaneous, and other pelvic fistulas at multimodality imaging.

A verification study of proposed pelvic lymph node localisation guidelines using nanoparticle-enhanced magnetic resonance imaging.

BACKGROUND AND PURPOSE: Normal sized pelvic lymph nodes are not easily identifiable on conventional imaging, but can be visualised with contrast-enhanced magnetic resonance imaging (MRI) using intravenous ultra-small particles of iron-oxide (USPIO). We have previously reported pelvic node clinical target volume (CTV) delineation guidelines for use with conventional imaging, derived from nodal mapping studies using USPIO. This study aims to verify these guidelines using an independent observer in a further patient cohort. MATERIALS AND METHODS: Ten patients with gynaecological cancer underwent MRI with and without intravenous USPIO. The guidelines were used to outline a pelvic node CTV on pre-contrast T2-weighted images. On post-contrast T2-weighted images the pelvic nodes were identified and outlined. The pre- and post-contrast images were co-registered and CTV examined for node coverage. RESULTS: By applying the guidelines, full coverage of 737 of 741 node outlines was achieved (>99%). Four nodes were not completely encompassed, two anterior external iliac nodes and two lateral external iliac nodes. CONCLUSIONS: MRI with USPIO contrast enabled the production of guidelines for localising a pelvic node CTV with conventional imaging. Application of these guidelines to a further patient cohort resulted in coverage of 99.5% node outlines demonstrating the reliability of this technique.

123I-metaiodobenzylguanidine (MIBG) scintigraphy for the detection of adrenal and extra-adrenal phaeochromocytomas: CT and MRI correlation.

CONTEXT: Evidence regarding the accuracy of [(123)I] metaiodobenzylguanidine (MIBG) imaging for phaeochromocytoma localization is currently limited to small series. OBJECTIVE: We present the largest series of primary phaeochromocytomas in which the performance of [(123)I]MIBG has been evaluated and correlated with cross-sectional imaging. DESIGN: We identified 76 patients with both preoperative [(123)I]MIBG and cross-sectional imaging for confirmed primary phaeochromocytoma between 1995 and 2005 at our institution. This comprised 60 adrenal tumours in 55 patients and 33 extra-adrenal tumours in 23 patients (2 patients had both adrenal and extra-adrenal tumours). Phaeochromocytoma metastases were not evaluated. MAIN OUTCOME MEASURE(S): [(123)I]MIBG studies were independently reviewed and correlated with CT and MRI examinations, as well as tumour functional status, to identify features that may predict a false negative [(123)I]MIBG result. RESULTS: The overall sensitivity of [(123)I]MIBG was 75%. Tumour detection was lower for extra-adrenal (58%) vs. adrenal (85%) phaeochromocytomas (P = 0.005). For extra-adrenal tumours, [(123)I]MIBG demonstrated 8 of 14 carotid body, 2 of 2 intrathoracic, 8 of 14 retroperitoneal and 2 of 3 pelvic phaeochromocytomas. Overall, MRI and CT demonstrated 68 of 68 and 72 of 74 primary phaeochromocytomas, respectively. Tumour size correlated with [(123)I]MIBG uptake for adrenal (P = 0.009) but not extra-adrenal tumours. When tumours were adjusted for size, no other imaging feature or functional status correlated with [(123)I]MIBG negativity, although two large [(123)I]MIBG negative adrenal tumours contained large areas of necrosis or haemorrhage. CONCLUSIONS: Extra-adrenal and small adrenal phaeochromocytomas are more likely to result in false negatives on [(123)I]MIBG. Tumoural necrosis or haemorrhage do not consistently relate to [(123)I]MIBG uptake, although adrenal phaeochromocytomas containing minimal solid tissue due to extensive necrosis may predict a negative [(123)I]MIBG result.

Clinical manifestations of familial paraganglioma and phaeochromocytomas in succinate dehydrogenase B (SDH-B) gene mutation carriers.

OBJECTIVE: Phaeochromocytomas and paragangliomas are familial in up to 25% of cases and can result from succinate dehydrogenase (SDH) gene mutations. The aim of this study was to describe the clinical manifestations of subjects with SDH-B gene mutations. DESIGN: Retrospective case-series. PATIENTS: Thirty-two subjects with SDH-B gene mutations followed up between 1975 and 2007. Mean follow-up of 5.8 years (SD 7.4, range 0-31). Patients seen at St Bartholomew's Hospital, London and other UK centres. MEASUREMENTS: Features of clinical presentation, genetic mutations, tumour location, catecholamine secretion, clinical course and management. RESULTS: Sixteen of 32 subjects (50%) were affected by disease. Two previously undescribed mutations in the SDH-B gene were noted. A family history of disease was apparent in only 18% of index subjects. Mean age at diagnosis was 34 years (SD 15.4, range 10-62). 50% of affected subjects had disease by the age of 26 years. 69% (11 of 16) were hypertensive and 80% (12 of 15) had elevated secretions of catecholamines/metabolites. 24% (6 of 25) of tumours were located in the adrenal and 76% (19 of 25) were extra-adrenal. 19% (3 of 16) had multifocal disease. Metastatic paragangliomas developed in 31% (5 of 16). One subject developed a metastatic type II papillary renal cell carcinoma. The cohort malignancy rate was 19% (6 of 32). Macrovascular disease was noted in two subjects without hypertension. CONCLUSION: SDH-B mutation carriers develop disease early and predominantly in extra-adrenal locations. Disease penetrance is incomplete. Metastatic disease is prominent but levels are less than previously reported. Clinical manifestations may include papillary renal cell carcinoma and macrovascular disease.

Adrenal phaeochromocytoma: correlation of MRI appearances with histology and function.

The purpose of this study was to describe the range of appearances of adrenal phaeochromocytomas on T2-weighted MRI, correlate appearances with histopathology, and quantify the incidence of the previously described hyperintense appearance. The appearance and MR characteristics of 44 phaeochromocytomas were reviewed retrospectively. T2-weighted appearances were grouped: (1) 'classical', homogeneous, high signal intensity, isointense to CSF; (2) homogeneous, isointense or minimally hyperintense to spleen, hypointense to CSF; (3) heterogeneous, marbled appearance; (4) heterogeneous, multiple high signal intensity pockets. All 44 adrenal phaeochromocytomas were well circumscribed, 1.2-15 cm in maximum diameter, with no visual or quantitative signal loss on chemical shift imaging. On T2-weighted MRI 5/44 (11%) had group 1 appearance; 15/44 (34%) group 2, 7/44 (16%) group 3; and 17/44 (39%) group 4. Homogeneous group 1 and 2 lesions were smaller (mean 4.5 cm) than heterogeneous group 3 and 4 lesions (mean 6.3 cm). Increasing MRI heterogeneity correlated pathologically with increasing amounts of haemorrhage, necrosis and fibrosis. No MRI features were predictive of malignancy. Non-functioning phaeochromocytomas were larger than functioning lesions. No size difference was seen between syndrome and sporadic lesions. In this large series we report a wide range of appearances of adrenal phaeochromocytomas on T2-weighted MRI. The previously described classical hyperintense phaeochromocytoma is relatively uncommon.

The optimal imaging of adrenal tumours: a comparison of different methods.

Computed tomography (CT; unenhanced, followed by contrast-enhanced examinations) is the cornerstone of imaging of adrenal tumours. Attenuation values of <10 Hounsfield units on an unenhanced CT are practically diagnostic for adenomas. When lesions cannot be characterised adequately with CT, magnetic resonance imaging (MRI) evaluation (with T1- and T2-weighted sequences and chemical shift and fat-suppression refinements) is sought. Functional nuclear medicine imaging is useful for adrenal lesions that are not adequately characterised with CT and MRI. Scintigraphy with [(131)I]-6-iodomethyl norcholesterol (a labelled cholesterol analogue) can differentiate adrenal cortical adenomas from carcinomas. Phaeochromocytomas appear as areas of abnormal and/or increased uptake of [(123)I]- and [(131)I]-meta-iodobenzylguanidine (a labelled noradrenaline analogue). The specific and useful roles of adrenal imaging include the characterisation of tumours, assessment of true tumour size, differentiation of adenomas from carcinomas and metastases, and differentiation of hyperfunctioning from non-functioning lesions. Adrenal imaging complements and assists the clinical and hormonal evaluation of adrenal tumours.

Imaging of neuroendocrine tumours (CT/MR/US).

Neuroendocrine tumours may be broadly divided into pancreatic endocrine tumours (PETs) and carcinoid neuroendocrine tumours (NETs). In both cases, patients may present with a clinical syndrome related to hormone secretion by the tumour. In these cases, cross-sectional imaging plays an important role in the localization of the primary tumour, the detection of metastases, and the assessment of response to treatment. Computed tomography (CT) is established as the primary modality, although following technological advances detection rates on magnetic resonance imaging (MRI) are now challenging those of CT. Endoscopic ultrasound has an important role in the preoperative assessment of the pancreas where a small functioning tumour or the possibility of multiple tumours is suspected. The sensitivity for the detection of small functioning tumours depends upon optimal technique, whichever modality is used. Non-functioning tumours frequently present late with mass effect, as there is no accompanying clinical syndrome. Carcinoid neuroendocrine tumours are most frequently localized on CT. MRI is usually used as a problem-solving tool. As technology evolves, detection rates may continue to improve, and the highest sensitivities may be achieved by a combination of different modalities.

Lymphoma of the spleen.

Splenic involvement in lymphoma is common, although it is detected with limited accuracy using most conventionally employed imaging techniques. This article reviews the spectrum of appearances of splenic lymphoma using both routine and more recently developed techniques, including functional imaging. The importance of accurate splenic imaging in lymphoma assessment is also discussed, which has changed in recent years due to advances in therapy resulting in improvements in overall prognosis for both advanced and relapsed disease.

Imaging in Cushing's syndrome.

Once the diagnosis of Cushing's syndrome (CS) has been established, the main step is to differentiate between ACTH dependent and independent disease. In adults, 80% of CS is due to ACTH-dependent causes and 20% due to adrenal causes. ACTH-secreting neoplasms cause ACTH-dependent CS. These are usually anterior pituitary microadenomas, which result in the classic Cushing's disease. Non-pituitary ectopic sources of ACTH, such as a small-cell lung carcinoma or carcinoid tumours, are the source of the remainder of ACTH-dependent disease. In the majority of patients presenting with clinical and biochemical evidence of CS, modern non-invasive imaging can accurately and efficiently provide the cause and the nature of the underlying pathology. Imaging is essential for determining the source of ACTH in ectopic ACTH production, locating the pituitary tumours and distinguishing adrenal adenomas, carcinomas and hyperplasias. In our chapter we review the adrenal appearances in ACTH-dependent and ACTH-independent CS. We also include a discussion on the use of MRI and CT for the detection and management of pituitary ACTH secreting adenomas. CT of the chest, abdomen and pelvis with intravenous injection of contrast medium is the most sensitive imaging modality for the identification of the ectopic ACTH source and detecting adrenal pathology. MRI is used for characterising adrenal adenomas, problem solving in difficult cases and for detecting ACTH-secreting pituitary adenomas.

Insulinomas may present with normoglycemia after prolonged fasting but glucose-stimulated hypoglycemia.

BACKGROUND: Insulinomas are rare but are the most common cause of hyperinsulinemic hypoglycemia in the adult population. Diagnosis of this pathology relies on clinical features along with laboratory tests and imaging investigations to aid in localization. One of the most robust standard tests used for establishing a biochemical diagnosis is the prolonged (72 h) fast. Currently, it is recommended that a prolonged supervised fast be performed, at least for 48 h if not for 72 h, and many would take the absence of hypoglycemia after a 72-h fast as evidence excluding the diagnosis. METHODS: We employed prolonged fasts and standard glucose tolerance tests, plus imaging studies and surgical pathology, in two patients with suspected insulinomas. RESULTS: The prolonged 72-h fast was normal in both the patients, whereas in both cases a prolonged oral glucose tolerance test clearly demonstrated the induction of severe hyperinsulinemia followed by significant hypoglycemia. Surgical removal confirmed the presence of insulinomas in each case. CONCLUSIONS: Although the sensitivity of the 72-h fast is high and still plays an important role in the diagnosis of an insulinoma, we suggest that a "normal" test result should be interpreted in the light of clinical symptoms.

The ectopic adrenocorticotropin syndrome: clinical features, diagnosis, management, and long-term follow-up.

CONTEXT: There are few large series of patients with ectopic, nonpituitary, corticotropin (ACTH) secretion (EAS). OBJECTIVE: The objective of this study was to analyze the clinical, biochemical, and radiological features, management, and treatment outcome of patients with EAS. DESIGN: This was a retrospective case-record study. SETTING: The setting for this study was a tertiary referral hospital center. PATIENTS: Forty patients with EAS were studied. MAIN OUTCOME MEASURES: Clinical, biochemical, and radiological features and response to therapy and survival were measured. RESULTS: The median follow-up was 5 yr (range, 2-30 yr). None of the dynamic tests achieved 100% accuracy, but bilateral inferior petrosal sinus sampling showed an absent central gradient in all but one case (one of 12). Imaging correctly identified the lesion at first investigation in 65% of cases. Bronchial carcinoid tumors were the most common cause of EAS (n = 12; 30%), followed by other neuroendocrine tumors (n = 13, 32.5%). In 12.5% of patients, the source of EAS was never found. Octreotide scintigraphy and whole-body venous sampling were of limited value. Surgical attempt at curative resection was successful in 83% (10 of 12) of patients with bronchial carcinoid tumors; others responded generally well to adrenolytic therapy or bilateral adrenalectomy. Tumor histology and the presence of distant metastases were the main predictors of overall survival (P < 0.05). CONCLUSIONS: A variety of tests and imaging studies are necessary for the correct diagnosis of the EAS, but even then, up to 20% of cases present a covert or occult EAS syndrome. These cases require a prolonged follow-up, review, and repetition of diagnostic tests and scans.

Diagnostic performance of nanoparticle-enhanced magnetic resonance imaging in the diagnosis of lymph node metastases in patients with endometrial and cervical cancer.

PURPOSE: Lymph node metastases affect management and prognosis of patients with gynecologic malignancies. Preoperative nodal assessment with computed tomography or magnetic resonance imaging (MRI) is inaccurate. A new lymph node-specific contrast agent, ferumoxtran-10, composed of ultrasmall particles of iron oxide (USPIO), may enhance the detection of lymph node metastases independent of node size. Our aim was to compare the diagnostic performance of MRI with USPIO against standard size criteria. METHODS: Forty-four patients with endometrial (n = 15) or cervical (n = 29) cancer were included. MRI was performed before and after administration of USPIO. Two independent observers viewed the MR images before lymph node sampling. Lymph node metastases were predicted using size criteria and USPIO criteria. Lymph node sampling was performed in all patients. RESULTS: Lymph node sampling provided 768 pelvic or para-aortic nodes for pathology, of which 335 were correlated on MRI; 17 malignant nodes were found in 11 of 44 patients (25%). On a node-by-node basis, sensitivity, specificity, positive predictive value (PPV), and negative predictive value (NPV) by size criteria were 29%*, 99%, 56%, and 96%, and by USPIO criteria (reader 1/reader 2) were 93%/82%* (*P = .008/.004), 97%/97%, 61%/59%, and 100%/99%, respectively (where [*] indicates the statistical difference of P = x/x between the two results marked by the asterisk). On a patient-by-patient basis, sensitivity, specificity, PPV, and NPV by size criteria were 27%*, 94%, 60%, and 79%, and by USPIO criteria (reader 1/reader 2) were 100%/91%* (*P = .031/.06), 94%/87%, 82%/71%, and 100%/96%, respectively. The kappa statistic was 0.93. CONCLUSION: Lymph node characterization with USPIO increases the sensitivity of MRI in the prediction of lymph node metastases, with no loss of specificity. This may greatly improve preoperative treatment planning.

Mapping pelvic lymph nodes: guidelines for delineation in intensity-modulated radiotherapy.

PURPOSE: To establish guidelines for delineating the clinical target volume for pelvic nodal irradiation by mapping the location of lymph nodes in relation to the pelvic anatomy. METHODS AND MATERIALS: Twenty patients with gynecologic malignancies underwent magnetic resonance imaging with administration of iron oxide particles. All visible lymph nodes were outlined. Five clinical target volumes were generated for each patient using modified margins of 3, 5, 7, 10, and 15 mm around the iliac vessels. The nodal contours were then overlaid and individual nodes analyzed for coverage. The volume of normal tissue within each clinical target volume and planning target volume was also measured to aid selection of the margin that could provide maximal nodal, but minimal normal tissue, coverage. RESULTS: In total, 1216 nodal contours were evaluated. The nodal coverage was 56%, 76%, 88%, 94%, and 99% using vessel margins of 3, 5, 7, 10, and 15 mm, respectively. The mean volume of bowel within the planning target volume was 146.9 cm3 with a 7-mm margin, 190 cm3 with a 10-mm margin, and 266 cm3 with a 15-mm margin. Minor modification to the 7-mm margin ensured 99% coverage of the pelvic nodes. CONCLUSION: Blood vessels with a modified 7-mm margin offer a good surrogate target for pelvic lymph nodes. By making appropriate adjustments, coverage of specific nodal groups may be increased and the volume of normal tissue irradiated decreased. On the basis of these findings, recommended guidelines for outlining pelvic nodes have been produced.