Musculoskeletal pitfalls and pseudotumours in the pelvis: a pictorial review for body imagers.

Many musculoskeletal abnormalities in the pelvis are first seen by body imagers while reviewing pelvic cross-sectional studies, and some of these abnormalities may mimic malignancy or another aggressive process. This article describes nine musculoskeletal pseudotumours and interpretative pitfalls that may be seen on CT, MRI and ultrasound imaging of the pelvis. Awareness of these pitfalls and pseudotumours may help avoid misdiagnosis and prevent inappropriate intervention or management.

Reproducibility and clinical correlations of post-treatment changes on CT of prostate cancer bone metastases treated with chemotherapy.

OBJECTIVES: The objective of this study was to determine whether, in patients with prostate cancer (PCa) bone metastases receiving chemotherapy, early post-treatment changes on CT are reproducible and associated with clinical outcomes. METHODS: Blinded to outcomes, two radiologists with 1 year and 5 years of experience independently reviewed CTs obtained before and 3 months after chemotherapy initiation in 38 patients with bone metastases from castration-resistant PCa, recording the size, matrix and attenuation of ≤5 lesions; presence of new lesions, extraosseous components, periosteal reactions and cortical thickening; and overall CT assessment (improved, no change or worse). Kappa statistics were used to assess inter-reader agreement; the Kruskal-Wallis test and Cox regression model were used to evaluate associations. RESULTS: Inter-reader agreement was low/fair for size change (concordance correlation coefficient=0.013), overall assessment and extraosseous involvement (κ=0.3), moderate for periosteal reaction and cortical thickening (κ=0.4-0.5), and substantial for CT attenuation (κ=0.7). Most metastases were blastic (Reader 1, 58%; Reader 2, 67%) or mixed lytic-blastic (Reader 1, 42%; Reader 2, 34%). No individual CT features correlated with survival. Readers 1 and 2 called the disease improved in 26% and 5% of patients, unchanged in 11% and 21%, and worse in 63% and 74%, respectively, with 64% interreader agreement. Overall CT assessment did not correlate with percentage change in prostate-specific antigen level. For the more experienced reader (Reader 2), patients with improved or unchanged disease had significantly longer median survival (p=0.036). CONCLUSIONS: In PCa bone metastases, interreader agreement is low in overall CT post-treatment assessment and varies widely for individual CT features. Improved or stable disease identified by an experienced reader is statistically associated with longer survival.

Prognostic significance of adrenal gland morphology at CT in patients with three common malignancies.

OBJECTIVES: To determine whether minor alterations in adrenal gland morphology at baseline CT in three common cancers indicate early metastasis. METHODS: 689 patients (237 with lung cancer, 228 with breast cancer, 224 with melanoma) underwent baseline and follow-up CTs that included the adrenals. Two readers independently scored each adrenal at baseline CT as normal, smoothly enlarged, nodular or mass-containing. Adrenals containing a mass >10 mm were excluded. The appearance of each adrenal on the latest available CT was assessed for change since baseline. Cox models were used to assess the association between adrenal morphology at initial CT and subsequent development of adrenal metastasis (defined as new mass >10 mm, corroborated by follow-up imaging). κ statistics were calculated to assess inter-reader agreement. RESULTS: Initial and follow-up CT evaluations were recorded for 1317 adrenals (median follow-up, 18.6 months). At initial CT, Readers 1 and 2 interpreted 1242 and 1230 adrenals as normal, 40 and 57 as smoothly enlarged, 29 and 25 as nodular, and 6 and 5 as containing masses ≤ 10 mm, respectively. κ-values were 0.52 (moderate) at initial CT and 0.70 (substantial) at follow-up. The hazard ratio for developing a metastasis at follow-up CT given an abnormal adrenal assessment at baseline was 0.7 [95% confidence interval (CI) 0.2-2.1; p = 0.47] for Reader 1, and 2.0 (95% CI 0.8-4.7; p = 0.12) for Reader 2. CONCLUSION: Minor morphological abnormalities of adrenals at initial CT did not represent early adrenal metastasis in most patients in this population.

Bone marrow oedema associated with benign and malignant bone tumours.

Bone marrow oedema is associated with a wide variety of pathological processes including both benign and malignant bone tumours. This imaging finding in relation to intraosseous tumours can aid in providing a more focused differential diagnosis. In this review, we will discuss the MR imaging of bone marrow oedema surrounding intraosseous neoplasms. The different pulse sequences used in differentiating underlying tumour from surrounding oedema are discussed along with the role of dynamic contrast enhanced MRI. Benign lesions commonly associated with bone marrow oedema include osteoid osteoma, osteoblastoma, chondroblastoma and Langerhan's cell histiocytosis. Metastases and malignant primary bone tumours such as osteosarcoma, Ewing's sarcoma and chondrosarcoma may also be surrounded by bone marrow oedema. The imaging findings of these conditions are reviewed and illustrated. Finally, the importance of bone marrow oedema in assessment of post chemotherapeutic response is addressed.

Breast cancer: assessing the use of routine pelvic CT in patient evaluation.

OBJECTIVE: The purpose of this study was to determine the benefit of routine pelvic CT in the evaluation of patients with primary breast cancer and to assess the frequency with which equivocal or abnormal findings on pelvic CT prompted the performance of additional studies or procedures that yielded results relevant to patient care. MATERIALS AND METHODS: The reports of 6628 body CT scans that included images of at least the pelvis in 2426 patients with breast cancer during a 9-year period were reviewed. The presence and sites of reported definite or probable metastases or pelvic tumors were recorded for each scan. Also, the types and results of diagnostic examinations and procedures prompted by equivocal or abnormal findings on pelvic CT were recorded. RESULTS: Pelvic metastases shown on CT were the only known site of metastasis in 13 (0.5%) of 2426 patients, and four other patients (0.2%) had new or enlarging pelvic metastases despite the presence of stable extrapelvic metastases. The pelvic metastases in these 17 patients were located in bone only in 11 patients, in adnexa only in five patients, and in adnexa, endometrium, and bone in one patient. In addition, pelvic CT led to the performance of 204 additional radiologic examinations, including 186 pelvic sonographic examinations, and 50 surgical procedures; 215 (84.6%) of these 254 additional examinations and procedures yielded normal, benign, or indeterminate results. CONCLUSION: The routine use of pelvic CT in the evaluation of patients with breast cancer has an extremely low yield and often prompts performance of pelvic sonographic or surgical procedures, the results of which were rarely relevant to cancer therapy.

Solitary fibrous tumor of the liver: imaging findings.

OBJECTIVE: This study describes the imaging features of solitary fibrous tumor of the liver in three patients. CONCLUSION: A single large, well-circumscribed, heterogeneously enhancing hepatic mass was present in each patient. These imaging features are suggestive of, but not diagnostic for, solitary fibrous tumor of the liver. The two benign and one malignant solitary fibrous tumors of the liver in this series were indistinguishable from one another on imaging studies.

Metastatic lobular carcinoma of the breast: patterns of spread in the chest, abdomen, and pelvis on CT.

OBJECTIVE: We determined the pattern of spread of metastatic lobular carcinoma in the chest, abdomen, and pelvis on CT. MATERIALS AND METHODS: We identified 57 women (age range, 30-79 years; mean age, 57 years) with metastatic lobular carcinoma of the breast who underwent CT of the chest, abdomen, or pelvis between 1995 and 1998. Then two experienced oncology radiologists retrospectively reviewed 78 CT examinations of those patients to identify sites of metastatic disease and to identify complications caused by metastases. RESULTS: Metastases were identified in bone in 46 patients (81%), lymph nodes in 27 patients (47%), lung in 19 patients (33%), liver in 18 patients (32%), peritoneum in 17 patients (30%), colon in 15 patients (26%), pleura in 13 patients (23%), adnexa in 12 patients (21%), stomach in nine patients (16%), retroperitoneum in nine patients (16%), and small bowel in six patients (11%). Eighteen patients (32%) had gastrointestinal tract involvement that manifested as bowel wall thickening. Hydronephrosis was present in six patients (11%). CONCLUSION: Although lobular carcinoma metastasized to common metastatic sites of infiltrating ductal carcinoma, lobular carcinoma frequently metastasized to unusual sites, including the gastrointestinal tract, peritoneum, and adnexa. Gastrointestinal tract involvement was as frequent as liver involvement, appearing as bowel wall thickening on CT. Hydronephrosis was a complication of metastatic lobular carcinoma.

Evaluation of tumor measurements in oncology: use of film-based and electronic techniques.

PURPOSE: To evaluate the variability in bidimensional computed tomography (CT) measurements obtained of actual tumors and of tumor phantoms by use of three measurement techniques: hand-held calipers on film, electronic calipers on a workstation, and an autocontour technique on a workstation. MATERIALS AND METHODS: Three radiologists measured 45 actual tumors (in the lung, liver, and lymph nodes) on CT images, using each of the three techniques. Bidimensional measurements were recorded, and their cross-products calculated. The coefficient of variation was calculated to assess interobserver variability. CT images of 48 phantoms were measured by three radiologists with each of the techniques. In addition to the coefficient of variation, the differences between the cross-product measurements of tumor phantoms themselves and the measurements obtained with each of the techniques were calculated. RESULTS: The differences between the coefficients of variation were statistically significantly different for the autocontour technique, compared with the other techniques, both for actual tumors and for tumor phantoms. There was no statistically significant difference in the coefficient of variation between measurements obtained with hand-held calipers and electronic calipers. The cross-products for tumor phantoms were 12% less than the actual cross-product when calipers on film were used, 11% less using electronic calipers, and 1% greater using the autocontour technique. CONCLUSION: Tumor size is obtained more accurately and consistently between readers using an automated autocontour technique than between those using hand-held or electronic calipers. This finding has substantial implications for monitoring tumor therapy in an individual patient, as well as for evaluating the effectiveness of new therapies under development.

Subcentimeter pulmonary nodules detected in patients with sarcoma.

Background. Subcentimeter pulmonary nodules are being detected with increasing frequency in patients with sarcoma due to the greater use of chest CT, the advent of helical (spiral) CT scanning and multidetector scanners, and the attendant decrease in image section thickness.Assessing the clinical significance of these pulmonary nodules is of particular importance in sarcoma patients, due to the frequent occurrence of pulmonary metastasis from sarcomas.Purpose. This article reviews the technical advances that have contributed to the increased detection of subcentimeter pulmonary nodules, statistics about subcentimeter pulmonary nodules and options for evaluating such nodules.

Staging of malignant pleural mesothelioma: comparison of CT and MR imaging.

OBJECTIVE: This article compares the accuracy of CT with that of MR imaging in staging of malignant pleural mesothelioma. SUBJECTS AND METHODS: Ninety-five patients were enrolled in a prospective staging protocol based on the International Mesothelioma Interest Group staging system. Sixty-five patients underwent CT and MR imaging and a surgical procedure (excluding percutaneous needle biopsy) to stage and resect the tumor. Receiver operating characteristic analyses were performed. CT and MR scans were interpreted independently by observers who were unaware of the results of the other imaging study; these imaging findings were compared with the results of surgery and pathologic examination. RESULTS: The areas under the receiver operating characteristic curves for eight of 10 features revealed by imaging showed no statistically significant differences between CT and MR imaging. However, MR imaging was superior to CT in revealing invasion of the diaphragm (A(z) = .55 for CT versus .82 for MR imaging) and in revealing invasion of endothoracic fascia or solitary resectable foci of chest wall invasion (A(z) = .46 for CT; A(z) = .69 for MR imaging). Several anatomic regions could not be evaluated because positive findings at surgery were rare. CONCLUSION: CT and MR imaging are of nearly equivalent diagnostic accuracy in staging malignant pleural mesothelioma. MR imaging is superior to CT in revealing solitary foci of chest wall invasion and endothoracic fascia involvement and in showing diaphragmatic muscle invasion; however, this advantage does not affect surgical treatment. For cost reasons, CT should be considered the standard diagnostic study before therapy.

Pulmonary nodules resected at video-assisted thoracoscopic surgery: etiology in 426 patients.

PURPOSE: To determine the etiology of pulmonary nodules resected at video-assisted thoracoscopic surgery (VATS) and establish the probabilities that single or multiple nodules resected at VATS represent malignancy in patients with or patients without known cancer. MATERIALS AND METHODS: Pathology reports from VATS performed between January 1995 and July 1997 were searched for data on gross specimens revealing pulmonary nodules 3 cm or smaller. Findings were correlated with clinical and histologic data. RESULTS: In 254 patients with one nodule resected at VATS, the nodules were malignant in 108 patients with and in 32 patients without known cancer (P < .03). Among 172 patients with multiple nodules resected, at least one nodule was malignant in 85 patients with and in 20 patients without known cancer (P > .05). Nodules larger than 1 cm were more likely to be malignant than were smaller nodules (P < .002). In patients with known malignancy, nodules smaller than 0.5 cm were more likely to be benign, whereas nodules larger than 0.5 cm but smaller than 1 cm were more likely to be malignant (P < .001). CONCLUSION: A single pulmonary nodule resected at VATS was more likely to be malignant in patients with known cancer. Nodules larger than 1 cm but smaller than 3 cm resected at VATS were more likely to be malignant. Nodules smaller than 0.5 cm were more likely to be benign.

Recurrent gallbladder carcinoma along laparoscopic cholecystectomy port tracks: CT demonstration.

PURPOSE: To describe the computed tomographic (CT) appearance of recurrent gallbladder carcinoma along port tracks after laparoscopic cholecystectomy and to assess the effect of recurrence on patient care. MATERIALS AND METHODS: Seventeen abdominal CT scans in 16 of 19 consecutive patients who underwent hepatic resection for gallbladder carcinoma diagnosed at laparoscopic cholecystectomy were reviewed retrospectively. Medical records were reviewed to determine the clinical effect of tumor recurrence along a port track. RESULTS: CT revealed 12 tumor recurrences along laparoscopic port tracks in six (32%) patients (mean, two recurrences per patient; range, one to four per patient). Eight (67%) CT-depicted recurrences appeared homogeneous, and nine (75%) directly involved subjacent omental fat. The mass was the only site of recurrence at CT in two (33%) patients. The presence of an abdominal wall tumor recurrence affected patient care in four (67%) of six patients. Histopathologic examination results confirmed recurrent tumor in all five (100%) patients who underwent biopsy. CONCLUSION: Tumor recurrence along port tracks is a potential complication of laparoscopic cholecystectomy when gallbladder carcinoma is present, even after subsequent hepatic resection is performed for attempted cure. Recurrences appear as a new or enlarging abdominal wall mass, often involving subjacent omental fat, and may be the only site of recurrent disease at CT. Demonstration of abdominal wall tumor recurrence affects patient care.

Bilateral renal masses after local Bacillus Calmette-Guerin therapy for postcystectomy ureteral cancer.

Bacillus Calmette-Guerin was administered through the ileal conduit of a 63-year-old man with upper tract recurrence of transitional cell carcinoma. Subsequent computed tomography showed bilateral renal masses, which were granulomatous at pathologic examination. The bacilli likely reached the kidneys via proven ileoureteral reflux. Patients with reflux may benefit from antituberculous prophylaxis.

Prevalence and importance of small hepatic lesions found at CT in patients with cancer.

PURPOSE: To assess the prevalence of small hepatic lesions discovered at computed tomography (CT) in patients with cancer and to determine the frequency with which they represent clinically important findings. MATERIALS AND METHODS: The authors reviewed the CT reports obtained in 2,978 patients with cancer during a 24-month period. Small hepatic lesions (lesions 1 cm or less in diameter or deemed too small to characterize by the interpreting radiologist) noted on the initial scan were assessed at follow-up CT. The number and type of any other intrahepatic lesion, the histologic type of the primary tumor, and the presence of extrahepatic metastatic disease were also recorded. RESULTS: Small hepatic lesions were reported in 378 (12.7%) patients; 15 (4.0%) of these patients also reportedly had other larger hepatic lesions that were interpreted as metastases. Small hepatic lesions demonstrated interval growth in 44 (11.6%) patients and were therefore considered metastatic. Small hepatic lesions in 303 (80.2%) patients demonstrated no interval growth (mean follow-up, 25.6 months; range, 6-56 months) and were therefore presumed benign. Small hepatic lesions in 31 (8.2%) patients were stable at follow-up of less than 6 months and were considered indeterminate. Among the three most common tumors (lymphoma and colorectal and breast cancers), small hepatic lesions were metastatic in 4%, 14%, and 22%, respectively. CONCLUSION: Although small hepatic lesions in patients with cancer more frequently are benign than malignant, these lesions represent metastases in 11.6% of patients.

Hepatocellular carcinoma: MR imaging findings in cirrhotic livers and noncirrhotic livers.

PURPOSE: To compare the magnetic resonance (MR) imaging findings of primary hepatocellular carcinoma (HCC) in cirrhotic versus noncirrhotic livers. MATERIALS AND METHODS: MR images in 36 patients with HCC (30 men and she women aged 42-84 years [mean age, 65 years]) were retrospectively reviewed. The number and size of hepatic lesions were assessed. Lesion margins were categorized as well circumscribed or ill defined. The presence of a capsule, intratumoral high signal intensity on T1-weighted MR images, and a stellate scar were determined. RESULTS: Eleven (31%) patients had MR imaging evidence of cirrhosis, and 25 (69%) did not: Lesions in cirrhotic livers differed significantly from those in noncirrhotic livers in terms of size (22 cm2 vs 99 cm2, P < .05), frequency of a solitary lesion (27% vs 72%, P < .05), and frequency of a central scar (6% vs 50%, P < .05). There was no difference between the cirrhotic and noncirrhotic livers with regard to tumor margin, intratumoral high signal intensity on T1-weighted images, or tumor capsule. CONCLUSION: Differences exist in the MR imaging appearance of HCC between patients with and those without cirrhosis, although there is overlap of imaging findings.

Clinical importance of reinterpretation of body CT scans obtained elsewhere in patients referred for care at a tertiary cancer center.

PURPOSE: To determine the frequency and clinical importance of discordance between the initial interpretation of computed tomographic (CT) scans of the body and subsequent interpretations in patients with biopsy-proved cancer. MATERIALS AND METHODS: The initial and reinterpretation reports for 213 CT scans of the body submitted for official review were compared independently by two radiologists. Sixty-nine sets of reports were excluded because the reviewing radiologists and the outside radiologists had prior CT scans from differing dates to use for comparison. One set of reports was excluded because of lack of clinical follow-up. RESULTS: The interpretations were graded as "agree" in 90 patients (63%), "major disagreement" in 24 patients (17%), and "minor disagreement" in 29 patients (20%). A theoretic change in treatment could have occurred in nine of 53 cases of disagreement (17%). An actual change in treatment occurred in five of 53 cases of disagreement (9%). CONCLUSION: Discordant interpretations were frequent (53 of 143 cases [37%]), were often major (24 of 143 cases [17%]), and resulted in actual treatment changes in five of all 143 cases (3%). Reinterpretation of body CT scans can have a substantial effect on the clinical care of individual patients with proved malignancy.

MR Imaging of Bone Marrow in Patients with Musculoskeletal Tumors.

Knowledge of the appearances of normal bone marrow, metastases involving marrow, and therapy-related marrow changes shown by MR imaging is necessary in order to avoid misdiagnosis. This article reviews MR imaging techniques and the findings that allow distinction of normal yellow (fatty) marrow and red marrow from tumor in marrow, as well as the identification of marrow changes resulting from radiation therapy or treatment with marrow-stimulating drugs in patients with musculoskeletal tumors.

Portal system thrombosis after splenectomy for neoplasm or chronic hematologic disorder: is routine surveillance imaging necessary?

PURPOSE: This study was undertaken to assess the frequency and sequelae of portal system thrombosis (PST) after splenectomy in patients with cancer or chronic hematologic disorders and to determine whether routine surveillance imaging for this potential complication is warranted. METHOD: The radiology reports of 203 consecutive patients with cancer or chronic hematologic disorders who underwent splenectomy between January 1990 and January 1997 were reviewed. Imaging examinations and medical records were reviewed for those in whom PST was found after splenectomy. RESULTS: One hundred twenty-three patients (60.6%) underwent CT (n = 88), sonography (n = 10), or both (n = 24) after splenectomy; one other patient underwent MRI. Twelve of these patients (9.8%) had thrombosis of the splenic, portal, and/or superior mesenteric veins. Their underlying diseases were myelofibrosis/ myelodysplastic syndrome (n = 8), lymphoma (n = 3), and leukemia (n = 1). At follow-up imaging (obtained in 10 of the 12 patients), PST had resolved (n = 5), worsened (n = 2), improved (n = 1), remained unchanged (n = 1), or resulted in cavernous transformation of the portal vein (n = 1). Nine of 12 patients were symptomatic. No patient died of PST. CONCLUSION: PST was an uncommon and typically unsuspected finding after splenectomy in this patient population, and no serious sequelae of PST were found. Routine surveillance imaging for PST after splenectomy does not seem warranted, but in symptomatic patients (particularly those with myelofibrosis/myelodysplastic syndrome), a high clinical suspicion and a low threshold for obtaining imaging examinations are needed.

Complex postcholecystectomy biliary disorders: preliminary experience with evaluation by means of breath-hold MR cholangiography.

PURPOSE: To assess preliminary experience with breath-hold single-shot fast spin-echo magnetic resonance (MR) cholangiography in complex postcholecystectomy biliary disorders. MATERIALS AND METHODS: MR cholangiography was performed in 17 consecutive patients referred for specialist surgical evaluation of suspected complex postcholecystectomy biliary disorders. Two readers, unaware of surgical, histopathologic, or other imaging findings, independently reviewed the MR cholangiographic images to assess the presence of biliary occlusion, peribiliary lesions, nonspecific biliary dilatation (biliary dilatation without an abrupt transition in caliber and without a visible underlying cause), bile duct stones, or biliary fistulas. Final diagnoses were established with surgery (n = 9), imaging other than MR (n = 6), and histopathologic review of the initial surgical specimen (n = 2). RESULTS: Final diagnoses were biliary occlusion (n = 8), peribiliary lesions (n = 3), nonspecific biliary dilatation (n = 3), bile duct stones (n = 2), and biliary-colonic fistula (n = 1). The two readers correctly categorized these diagnoses in 15 (88%) and 13 (76%) of the 17 cases, with excellent interobserver agreement (kappa = 0.82). CONCLUSION: Single-shot fast spin-echo MR cholangiography is an accurate, noninvasive modality for the assessment of complex postcholecystectomy biliary disorders.