Mass-like peripheral zone enhancement on CT is predictive of higher-grade (Gleason 4 + 3 and higher) prostate cancer

PURPOSE

To determine whether focal peripheral zone enhancement on routine venous-phase CT is predictive of higher-grade (Gleason 4 + 3 and higher) prostate cancer.

MATERIALS AND METHODS

IRB approval was obtained and informed consent waived for this HIPAA-compliant retrospective study. Forty-three patients with higher-grade prostate cancer (≥Gleason 4 + 3) and 96 with histology-confirmed lower-grade (≤Gleason 3 + 4 [n = 47]) or absent (n = 49) prostate cancer imaged with venous-phase CT comprised the study population. CT images were reviewed by ten blinded radiologists (5 attendings, 5 residents) who scored peripheral zone enhancement on a scale of 1 (benign) to 5 (malignant). Mass-like peripheral zone enhancement was considered malignant. Likelihood ratios (LR) and specificities were calculated. Multivariate conditional logistic regression analyses were conducted.

RESULTS

Scores of "5" were strongly predictive of higher-grade prostate cancer (pooled LR+ 9.6 [95% CI 5.8-15.8]) with rare false positives (pooled specificity: 0.98 [942/960, 95% CI 0.98-0.99]; all 10 readers had specificity ≥95%). Attending scores of "5" were more predictive than resident scores of "5" (LR+: 14.7 [95% CI 5.8-37.2] vs. 7.6 [95% CI 4.2-13.7]) with similar specificity (0.99 [475/480, 95% CI 0.98-1.00] vs. 0.97 [467/480, 95% CI 0.96-0.99]). Significant predictors of an assigned score of "5" included presence of a peripheral zone mass (p < 0.0001), larger size (p < 0.0001), and less reader experience (p = 0.0008). Significant predictors of higher-grade prostate cancer included presence of a peripheral zone mass (p = 0.0002) and larger size (p < 0.0001).

CONCLUSION

Focal mass-like peripheral zone enhancement on routine venous-phase CT is specific and predictive of higher-grade (Gleason 4 + 3 and higher) prostate cancer.

Primary and secondary neoplasms of the spleen

With the exception of lymphoma involving the spleen, other primary and secondary neoplasms are rare and infrequently encountered. Primary malignant neoplasms involving the spleen are lymphoma and angiosarcoma. Primary benign neoplasms involving the spleen include hemangioma, lymphangioma, littoral cell angioma and splenic cyst and solid lesions such as hamartoma and inflammatory pseudotumor.

Mesenteric venous collateral vessels mimicking cystic pancreatic neoplasm

We report an unusual case of intrapancreatic mesenteric venous collateral vessels following partial pancreatic surgical resection resembling pancreatic neoplasm upon greyscale sonographic and unenhanced CT examinations.

Phase I radiation dose-escalation trial of intensity-modulated radiotherapy (IMRT) with concurrent fixed dose-rate gemcitabine (FDR-G) for unresectable pancreatic cancer

4602

Background: Current treatments of non-metastatic, unresectable pancreatic cancer result in poor survival and nearly uniform local persistence of disease. We hypothesized that intensification of local therapy would result in better local control and improve survival. The primary objective of this trial was to determine maximum tolerated radiation dose delivered with IMRT and concurrent FDR-G. Methods: Eligibility included tissue diagnosis of adenocarcinoma, unresectable by radiological criteria, Zubrod performance of 0–2, ANC of ≥ 1500/mm3, platelets ≥ 100,000/mm3, creatinine < 2 mg/dl, bilirubin < 3 mg/dl, ALT and AST ≤ 2.5 x ULN, and informed consent. Patients (pts) received FDR-G (1000 mg/m2, 100-minute infusion) on days -22 and -15. IMRT started day 1 (radiation dose levels [L2-L6] 50, 52.5, 55, 57.5 and 60 Gy, all in 25 fractions) with concurrent FDR-G on days 1, 8, 22, and 29. GTV was defined on pancreas protocol CT in the treatment position. PTV was GTV plus 1 cm expansion. Active Breathing Control was used to reduce breathing motion, except in 3 pts, in whom 4D CT was used to generate an ITV. Post IMRT, up to 4 cycles of FDR-G were given. DLT was defined as GI toxicity ≥ G3, neutropenic fever, or deterioration in Zubrod to ≥3 between day 1 and 126. IMRT dose level was assigned using the Time-to-Event Continual Reassessment Method. With a sample size of 50, the design allows concurrent assessment of efficacy. Results: From 8/06, 27 pts have been accrued. DLTs have been observed in 6 (G3 anorexia, nausea vomiting, and/or dehydration [5 pts]; duodenal bleed [1 pt]). The posterior estimates of probability of DLT are 0.17, 0.21, 0.24, 0.27, and 0.28 for L2 to L6, respectively. The response rate is 52.4% (95% CI 29.8% to 74.3%). The median overall survival and progression-free survival are 23.1 months (95% CI 9–23.1) and 7.2 months (95% CI 5.0–8.0), respectively. Only 1 patient (4%) progressed locally. Two patients have undergone resection (R0), and demonstrated near- and complete pathological responses. Conclusions: High dose radiotherapy and concurrent FDR-G, utilizing the techniques above, is well tolerated and results in highly encouraging response rates, local control rates and overall survival.

No significant financial relationships to disclose.

A phase I study of oxaliplatin, full-dose gemcitabine and concurrent radiation therapy in patients with pancreatic cancer

4107

Background: We previously demonstrated safety and efficacy of full dose gemcitabine (GEM) and radiation therapy (RT) in patients (pts) with pancreatic cancer (PC). Our preclinical studies have shown that GEM with oxaliplatin (OX) preserves radiosensitization with synergistic cytotoxicity. To enhance local and systemic treatment effects, we initiated a study of OX and GEM with concurrent RT. Methods: Pts with untreated PC received up to 4 cycles of GEM day 1, 8, 15 and OX days 1, 15 repeated at 28 day intervals. RT (27 Gy in 1.8 Gy fractions to gross tumor volume with 1 cm margin) was given during cycle 1 and repeated in cycle 4. Surgery occurred after cycle 2 in resectable pts. Dose escalation was guided using time-to-event continuous reassessment method (TITE-CRM). Dose levels 1–4 GEM 1 g/m2 IV over 30 min and OX 40, 55, 70, 85 mg/m2 IV over 90 min; dose level 5, 6 OX dose remained 85 mg/m2 but infusion time for GEM 1 g/m2 was increased to 65, 100 min, respectively. Trial objective is to determine dose level associated with DLT thru cycle 2 in ≤ 20% of pts; planned accrual is 40 pts evaluable for DLT. Results: 40 pts have been enrolled (median age 63, men/women 26/14) with resectable (10), unresectable (27), and metastatic (3) PC. 29 pts have completed 2 cycles and 11 pts 4 cycles. After 2 cycles CA19–9 decreased > 50% in 14 of 24 evaluable pts (58%). Six of 8 explored pts underwent margin negative resection with 1 path CR and 2 with small residual microscopic foci only. Per RECIST, CT response of the primary lesion after 2 cycles included 3 PR, 23 SD and 1 PD. Two additional PR were seen after cycle 4. Thirty pts are presently evaluable for DLT; 7 pts have suffered DLT including grade 4 platelets (4), decline in PS (2), GI bleed (1) and grade 3 weight loss (1). Current estimated probability of DLT is 21% (95% CI 11%,34%) for dose level 3 and 24% (95% CI 13%,37%) for dose level 4. Conclusions: The addition of OX 70–85 mg/m2 days 1, 15 to full dose GEM based RT is tolerable and efficacious. A neoadjuvant phase II study in resectable PC using the MTD defined in this phase I study is planned. Supported by Sanofi-Aventis.

[Table: see text]

Assessment of the clinical utility of the rim and comet-tail signs in differentiating ureteral stones from phleboliths

OBJECTIVE

This study was designed to assess interobserver variability in identifying the rim and comet-tail signs and to determine the clinical utility of these signs in determining whether or not the calcifications with which they are associated represent ureteral calculi.

MATERIALS AND METHODS

Two radiologists and a radiology resident, unaware of the final diagnosis, reviewed preselected helical CT images from renal stone examinations in patients with 65 indeterminate pelvic calcifications. Assessment of calcifications for rim or comet-tail signs was performed independently of an assessment for the following five secondary signs of urinary tract obstruction: caliectasis, pelviectasis, ureterectasis, perinephric stranding, and renal enlargement. Agreement in identifying rim and comet-tail signs was assessed by obtaining kappa statistics. The utility the of rim or comet-tail signs in determining whether ureterolithiasis was present in patients in whom perinephric stranding and ureterectasis were present or absent was determined. The frequency with which one or more of each of the five assessed secondary signs was identified ipsilateral to a calcification having rim or comet-tail signs was also tabulated.

RESULTS

Kappa values for interobserver agreement ranged from 0.49 to 0.73. In only one patient was a rim sign detected in the absence of ureterectasis and perinephric stranding. Reviewers identified at least three of the five assessed secondary signs ipsilateral to calcifications showing a rim sign in all but one patient (by each radiologist) and four patients (by the resident). When three or more secondary signs of obstruction were seen ipsilateral to a calcification having a comet-tail sign, in all but one instance, this was because the calcification was a ureteral calculus or because there was a separate ipsilateral ureteral calculus.

CONCLUSION

In many instances, observers did not agree about whether the rim and comet-tail signs were present. The rim sign was observed in the absence of any secondary signs of urinary tract obstruction in only one (1.5%) of the 65 patients in our series (95% confidence interval, 0-5.3%). The comet-tail sign, when accompanied by secondary signs of obstruction, should indicate that an ipsilateral ureteral stone is present and not the reverse.

Effectiveness of abdominal compression during helical renal CT

RATIONALE AND OBJECTIVES

The authors performed this study to assess the effect of abdominal compression on opacification and distention of the proximal renal collecting system during helical computed tomography (CT).

MATERIALS AND METHODS

Abdominal compression was applied during helical CT in 31 patients who were scanned 150 and 300 seconds after initiating a dynamic bolus injection of contrast material. Two reviewers assessed renal collecting system opacification and measured the maximal short-axis diameter of the collecting system at three locations: the upper pole, the lower pole, and the proximal ureter. A similar evaluation was performed in a control group of 29 patients who underwent CT without compression at 300 seconds after initiating the injection of contrast material.

RESULTS

Both reviewers noted collecting system opacification at all locations in 52 of 56 noncompressed collecting systems scanned at 300 seconds, 57 of 59 compressed collecting systems scanned at 300 seconds, but only 26 of 59 compressed collecting systems scanned at 150 seconds. Measured collecting system distention was statistically significantly greater at 300 seconds in patents who received compression than in patients who did not (P = .0013). For patients who received compression, measured collecting system distention was statistically significantly greater on scans obtained at 300 seconds than on scans obtained at 150 seconds (P = .0001).

CONCLUSION

Abdominal compression during renal helical CT produces a detectable increase in renal collecting system distention. In patients who receive compression, scanning at 300 seconds rather than at 150 seconds results in greater collecting system distention and more consistent opacification.

Can endoscopic ultrasound or magnetic resonance cholangiopancreatography replace ERCP in patients with suspected biliary disease? A prospective trial and cost analysis

OBJECTIVES

ERCP is the gold standard for pancreaticobiliary evaluation but is associated with complications. Less invasive diagnostic alternatives with similar capabilities may be cost-effective, particularly in situations involving low prevalence of disease. The aim of this study was to compare the performance of endoscopic ultrasound (EUS) with magnetic resonance cholangiopancreatography (MRCP) and ERCP in the same patients with suspected extrahepatic biliary disease. The economic outcomes of EUS-, MRCP-, and ERCP-based diagnostic strategies were evaluated.

METHODS

Prospective cohort study of patients referred for ERCP with suspected biliary disease. MRCP and EUS were performed within 24 h before ERCP. The investigators were blinded to the results of the alternative imaging studies. A cost-utility analysis was performed for initial ERCP, MRCP, and EUS strategies for these patients.

RESULTS

A total of 30 patients were studied. ERCP cholangiogram failed in one patient, and another patient did not complete MRCP because of claustrophobia. The final diagnoses (N = 28) were CBD stone (mean = 4 mm; range = 3-6 mm) in five patients; biliary stricture in three patients, and normal biliary tree in 20. Two patients had pancreatitis after therapeutic ERCP, one after precut sphincterotomy followed by a normal cholangiogram. EUS was more sensitive than MRCP in the detection of choledocolithiasis (80% vs 40%), with similar specificity. MRCP had a poor specificity and positive predictive value for the diagnosis of biliary stricture (76%/25%) compared to EUS (100%/100%), with similar sensitivity. The overall accuracy of MRCP for any abnormality was 61% (95% CI = 0.41-0.78) compared to 89% (CI = 0.72-0.98) for EUS. Among those patients with a normal biliary tree, the proportion correctly identified with each test was 95% for EUS and 65% for MRCP (p < 0.02). The cost for each strategy per patient evaluated was $1346 for ERCP, $1111 for EUS, and $1145 for MRCP.

CONCLUSIONS

In this patient population with a low disease prevalence, EUS was superior to MRCP for choledocholithiasis. EUS was most useful for confirming a normal biliary tree and should be considered a low-risk alternative to ERCP. Although MRCP had the lowest procedural reimbursement, the initial EUS strategy had the greatest cost-utility by avoiding unnecessary ERCP examinations.

Poor CD4 T cell restoration after suppression of HIV-1 replication may reflect lower thymic function

OBJECTIVE

To characterize immune phenotype and thymic function in HIV-1-infected adults with excellent virologic and poor immunologic responses to highly active antiretroviral therapy (HAART).

METHODS

Cross-sectional study of patients with CD4 T cell rises of > or = 200 x 10(6) cells/l (CD4 responders; n = 10) or < 100 x 10(6) cells/l (poor responders; n = 12) in the first year of therapy.

RESULTS

Poor responders were older than CD4 responders (46 versus 38 years; P < 0.01) and, before HAART, had higher CD4 cell counts (170 versus 35 x 106 cells/l; P = 0.11) and CD8 cell counts (780 versus 536 x 10(6) cells/l; P = 0.02). After a median of 160 weeks of therapy, CD4 responders had more circulating naive phenotype (CD45+CD62L+) CD4 cells (227 versus 44 x 10(6) cells/l; P = 0.001) and naive phenotype CD8 cells (487 versus 174 x 10(6) cells/l; P = 0.004) than did poor responders (after 130 weeks). Computed tomographic scans showed minimal thymic tissue in 11/12 poor responders and abundant tissue in 7/10 responders (P = 0.006). Poor responders had fewer CD4 cells containing T cell receptor excision circles (TREC) compared with CD4 responders (2.12 versus 27.5 x 10(6) cells/l; P = 0.004) and had shorter telomeres in CD4 cells (3.8 versus 5.3 kb; P = 0.05). Metabolic labeling studies with deuterated glucose indicated that the lower frequency of TREC-containing lymphocytes in poor responders was not caused by accelerated proliferation kinetics.

CONCLUSION

Poor CD4 T cell increases observed in some patients with good virologic response to HAART may be caused by failure of thymic T cell production.

Multi--detector row helical CT of the pancreas: effect of contrast-enhanced multiphasic imaging on enhancement of the pancreas, peripancreatic vasculature, and pancreatic adenocarcinoma

PURPOSE

To determine the optimal phase for enhancement of the normal pancreas and peripancreatic vasculature and the maximal tumor-to-pancreatic parenchymal enhancement difference by using multiphase, contrast material-enhanced, multi-detector row helical computed tomography (CT).

MATERIALS AND METHODS

Forty-nine patients with a normal-appearing pancreas but suspected of having pancreatic abnormality and 28 patients with proved pancreatic adenocarcinoma underwent multiphase, contrast-enhanced, multi-detector row CT during the arterial phase (AP), pancreatic parenchymal phase (PPP), and portal venous phase (PVP). Attenuation values of the normal pancreas, pancreatic adenocarcinoma, celiac and superior mesenteric arteries, and superior mesenteric and portal veins were measured during all three imaging phases. Quantitative analysis of these measurements and subjective qualitative analysis of tumor conspicuity were performed.

RESULTS

Maximal enhancement of the normal pancreatic parenchyma occurred during the PPP. Maximal tumor-to-parenchyma attenuation differences during the PPP and PVP were equivalent but greater than that during the AP. Subjective analysis revealed that tumor conspicuity during the PPP and PVP was equivalent but superior to that during the AP. Maximal arterial enhancement was seen during the PPP, and maximal venous enhancement was seen during the PVP.

CONCLUSION

A combination of PPP and PVP imaging is sufficient for detection of pancreatic adenocarcinoma, because it provides maximal pancreatic parenchymal and peripancreatic vascular enhancement. AP imaging can be reserved for patients in whom CT angiography is required.

Ulcerlike lesions of the aorta: imaging features and natural history

PURPOSE

To document the natural history of ulcerlike aortic lesions and determine whether any computed tomographic (CT) features predict outcome.

MATERIALS AND METHODS

CT scans from 1994 to 1998 that depicted an ulcerlike aortic lesion were retrospectively evaluated. Features evaluated included lesion and aortic size and intramural hematoma. Initial CT findings were correlated with clinical data and subsequent CT findings.

RESULTS

There were 56 lesions in 38 patients. Follow-up (mean, 18.4 months) CT scans were available for 33 lesions. Stability of the lesion and adjacent aorta was noted in 21 lesions. Two lesions were unchanged, although associated intramural hematoma regressed over 1-2 months. Ten lesions showed mild to moderate increase in aortic diameter (mean follow-up, 19.8 months) either with (seven lesions) or without (one lesion) increase in size of the lesion or with incorporation of the lesion into the aortic wall contour (two lesions). Of all 56 lesions, 37 were clinically stable, two were associated with recurrent chest and/or back pain, eight underwent surgical resection or stent placement, and two were in patients who died. Seven lesions were in patients lost to follow-up. No initial CT feature was predictive of CT outcome, although lack of pleural effusion correlated with clinical stability.

CONCLUSION

Most ulcerlike aortic lesions are asymptomatic and do not enlarge. About one-third of lesions progress, generally resulting in mild interval aortic enlargement.

The accuracy of EUS and helical CT in the assessment of vascular invasion by peripapillary malignancy

BACKGROUND

The relative accuracy of helical CT and EUS for defining the local resectability of peripapillary malignancies is undefined.

METHODS

Fifty-one patients with a peripapillary malignancy and no metastatic disease were prospectively evaluated with helical CT and EUS. Imaging results were compared with surgical staging, and a tumor was defined as resectable when there was no macroscopic or microscopic residual tumor.

RESULTS

Nine patients had surgically confirmed locally unresectable disease, which was accurately predicted by EUS in 6 patients (sensitivity 67%) and by helical CT in 3 patients (sensitivity 33%; p = 0.35). When only patients with complete EUS examinations were included, the sensitivities of EUS and helical CT for vascular invasion were 100% and 33% (p = 0.06), respectively. When all patients not undergoing surgery because of imaging evidence of locally unresectable disease were included, the sensitivities were 100% and 62.5% (p = 0.02), respectively. One of 15 patients with a tumor amenable to surgical resection was labeled as unresectable by EUS but subsequently had a local recurrence of the tumor. The specificities of EUS (93%) and helical CT (100%) were similar.

CONCLUSION

EUS is more sensitive than helical CT for detecting vascular invasion by peripapillary malignancies and should be added to staging protocols, particularly when findings on helical CT are equivocal.

Bladder tumor detection at virtual cystoscopy

PURPOSE

To investigate the utility of computed tomographic (CT) virtual cystoscopy in the detection of bladder tumors.

MATERIALS AND METHODS

Twenty-six patients suspected or known to have bladder neoplasms underwent CT virtual and conventional cystoscopy. The bladder was insufflated with carbon dioxide through a Foley catheter. Helical CT of the bladder was then performed. The data were downloaded to a workstation for interactive intraluminal navigation. Two radiologists blinded to the results of conventional cystoscopy independently reviewed the transverse and virtual images, with consensus readings for cases with discrepant results.

RESULTS

Thirty-six (90%) of 40 bladder lesions proved at conventional cystoscopy were detected with a combination of transverse and virtual images. Four (10%) of 40 bladder lesions, all smaller than 5 mm, were undetected. Transverse and virtual images were complementary, since six polypoid lesions smaller than 5 mm depicted on the virtual images were not seen on the transverse images. In contrast, areas of wall thickening were more readily appreciated on transverse images. CT with patients in both supine and prone positions was necessary, since seven (19%) and five (14%) of 36 lesions were seen only on supine and prone images, respectively.

CONCLUSION

CT virtual cystoscopy is a promising technique for use in bladder tumor detection of lesions larger than 5 mm. Optimal evaluation requires adequate bladder distention with the patient in both supine and prone positions and interpretation of both transverse and virtual images.

Delayed enhanced CT of lipid-poor adrenal adenomas

OBJECTIVE

Although representing a minority of adrenal adenomas, the lipid-poor variety cannot be accurately identified on unenhanced CT or chemical shift MR imaging. We compared the delayed contrast-enhanced CT features of lipid-poor adenomas with those of lipid-rich adenomas and of adrenal nonadenomas to determine whether there were differences in the washout features between these groups of lesions.

SUBJECTS AND METHODS

Eighteen proven lipid-poor adenomas, 56 lipid-rich adenomas, and 40 adrenal nonadenomas underwent CT before, immediately after, and 15 min delay after IV contrast injection. Region-of-interest measurements were made of all adrenal lesions at the three time points. The degree of enhancement, enhancement washout, percentage enhancement washout, and relative percentage enhancement washout were calculated for each adrenal mass. Pooled data were analyzed statistically. Optimal threshold values for diagnosing adrenal adenomas were also determined.

RESULTS

The mean CT attenuation of lipid-poor adenomas was significantly higher than that of lipid-rich adenomas at all three phases but not significantly different from that of nonadenomas. The mean percentage enhancement washout on images obtained 15 min after administration of contrast material was similar for lipid-rich and lipid-poor adenomas but was significantly higher than that of nonadenomas. The mean relative percentage enhancement washout was significantly different among all three groups.

CONCLUSION

Lipid-poor adenomas cannot be differentiated from adrenal nonadenomas on the basis of a single mean attenuation value. However, lipid-poor adrenal adenomas show enhancement and enhancement washout features nearly identical to lipid-rich adenomas and can be distinguished from nonadenomas on the basis of a percentage washout threshold value of 60% and a relative percentage washout of 40%.

Initial results for Hybrid SPECT--conjugate-view tumor dosimetry in 131I-anti-B1 antibody therapy of previously untreated patients with lymphoma

A study of the use of 131I-labeled anti-B1 monoclonal antibody, proceeded by an unlabeled predose, for therapy of previously untreated non-Hodgkin's lymphoma patients has recently been completed at the University of Michigan, Ann Arbor. More than half of the patients treated were imaged intratherapy with SPECT to separate apparently large tumors, unresolved by conjugate views, into individual ones specified by CT scan. The dosimetry of these tumors is reported here.

METHODS

The activity-quantification procedure used 3-dimensional CT-to-SPECT fusion so that attenuation maps could be computed from CT and that volumes of interest could be drawn on the CT slices and transferred to the SPECT images. Daily conjugate-view images after a tracer dose of labeled anti-B1 antibody followed by an unlabeled predose provided the shape of the time-activity curve for the calculation of therapy dosimetry. Reconstructed SPECT counts that were within a volume of interest were converted to activity by using a background-and-radius-adaptive conversion factor. Activities were increased for tumors less than 200 g using a recovery-coefficient factor derived from activity measurements for a set of spheres with volumes ranging from 1.6 to 200 cm3. The calculated tumor radiation absorbed dose was based, in part, on the CT volume and on the intratherapy-SPECT activity.

RESULTS

The mean of the radiation dose values for 131 abdominal or pelvic tumors in 31 patients was 616 cGy with a standard deviation of +/- 50 cGy. The largest dose was 40 Gy and the smallest dose was 73 cGy. The mean volume for the tumors was 59.2 +/- 11.2 cm3. The correlation coefficient between absorbed dose and tumor volume was small (r2 = 0.007), and the slope of the least-squares fit represented a decrease of only 36.4 cGy per 100 cm3 increase in volume. This small slope may reflect a characteristic of anti-B1 antibody therapy that is important for its success. The mean absorbed dose per unit administered activity was 1.83 +/- 0.145 Gy/GBq. The largest value was 12.6 Gy/GBq, and the smallest value was 0.149 Gy/GBq. The mean dose for 9 axillary tumors in 5 patients was significantly lower than the average dose for abdominal and pelvic tumors (P = 0.01). Therefore, axillary tumors should be grouped separately in assessing dose-response relationships. Anecdotal patient results tended to verify the validity of using the shape of the conjugate-view time-activity curve for the average SPECT-intratherapy curve. However, there was also an indication that the shape varies somewhat for individual tumors with respect to time to peak.

CONCLUSION

Hybrid SPECT-conjugate-view dosimetry provided radiation absorbed dose estimates for the individual patient tumors that were resolved by CT.

Radioimmunotherapy with iodine (131)I tositumomab for relapsed or refractory B-cell non-Hodgkin lymphoma: updated results and long-term follow-up of the University of Michigan experience

CD20-targeted radioimmunotherapy is a promising new treatment for B-cell non-Hodgkin lymphoma (NHL). We now provide updated and long-term data on 59 chemotherapy-relapsed/refractory patients treated with iodine (131)I tositumomab in a phase I/II single-center study. Fifty-three patients received individualized therapeutic doses, delivering a specified total-body radiation dose (TBD) based on the clearance rate of a preceding dosimetric dose. Six patients received dosimetric doses only. Dose-escalations of TBD were conducted separately in patients who had or had not undergone a prior autologous stem cell transplant (ASCT) until a nonmyeloablative maximally tolerated TBD was established (non-ASCT = 75 cGy, post-ASCT = 45 cGy). Fourteen additional non-ASCT patients were treated with 75 cGy. Unlabeled antibody was given prior to labeled dosimetric and therapeutic doses to improve biodistribution. Forty-two (71%) of 59 patients responded; 20 (34%) had complete responses (CR). Thirty-five (83%) of 42 with low-grade or transformed NHL responded versus 7 (41%) of 17 with de novo intermediate-grade NHL (P =.005). For all 42 responders, the median progression-free survival was 12 months, 20.3 for those with CR. Seven patients remain in CR 3 to 5.7 years. Sixteen patients were re-treated after progression; 9 responded and 5 had a CR. Reversible hematologic toxicity was dose limiting. Only 10 patients (17%) had human anti-mouse antibodies detected. Long-term, 5 patients developed elevated thyroid-stimulating hormone levels, 5 were diagnosed with myelodysplasia and 3 with solid tumors. A single, well-tolerated treatment with iodine (131)I tositumomab can, therefore, produce frequent and durable responses in NHL, especially low-grade or transformed NHL. (Blood. 2000;96:1259-1266)

Sensitivity of CT scout radiography and abdominal radiography for revealing ureteral calculi on helical CT: implications for radiologic follow-up

OBJECTIVE

We compared the sensitivity of CT scout radiography with that of abdominal radiography in revealing ureteral calculi on unenhanced helical CT.

MATERIALS AND METHODS

Over a 6-month period, patients presenting to the emergency department with acute flank pain were examined with standard abdominal radiography and unenhanced helical CT, which included CT scout radiography. In 60 patients in whom a diagnosis of ureteral calculus was made, CT scout radiographs and abdominal radiographs were examined by two interpreters who assessed whether stones could be visualized. All CT scout radiographs were viewed on a workstation using optimized window settings.

RESULTS

CT scout radiography and abdominal radiography revealed 28 (47%) and 36 (60%) of 60 ureteral calculi, respectively. All ureteral calculi that appeared on CT scout radiography also appeared on abdominal radiography. However, eight calculi that were visible on abdominal radiography were not visible on CT scout radiography. CT scout radiography and abdominal radiography revealed 28% and 46% of 39 calculi less than or equal to 3 mm in diameter, respectively. For 21 calculi larger than 3 mm, the sensitivity of CT scout radiography and abdominal radiography was 81% and 86%, respectively.

CONCLUSION

Abdominal radiography is more sensitive than CT scout radiography in revealing ureteral calculi; however, some calculi revealed on unenhanced helical CT cannot be seen on either abdominal radiography or CT scout radiography. Ureteral calculi not visible on either study can only be followed, when necessary, with unenhanced helical CT.

Tumor-absorbed-dose estimates versus response in tositumomab therapy of previously untreated patients with follicular non-Hodgkin's lymphoma: preliminary report

I-131-radiolabeled tositumomab (Anti-B1 Antibody), in conjunction with unlabeled tositumomab, was employed in a phase II clinical trial for the therapy of 76 previously-untreated follicular-non-Hodgkin's-lymphoma patients at the University of Michigan Cancer Center. For all patients, conjugate-view images were obtained at six to eight time points on seven consecutive days after a tracer infusion of the antibody. A SPECT image set was obtained on day two or three after the therapy infusion for 57 of the patients. Of these, 55 are suitable for dosimetric evaluation. To date, we have completed analysis and response characterization of 20 patients from the subset of 55. All 20 patients had either a complete response (CR) or a partial response (PR). Conjugate-views provided a time-activity curve for a composite of nearby, individual tumors. These tumors were unresolved in the anterior-posterior projection. Pre-therapy CT provided volume estimates. Therapy radiation dose was computed for the composite tumor by standard MIRD methods. Intra-therapy SPECT allowed the calculation of a separate dose estimate for each individual tumor associated with the composite tumor. Average dose estimates for each patient were also calculated. The 30 individual tumors in PR patients had a mean radiation dose of (369 +/- 54) cGy, while the 56 individual tumors in CR patients had a mean radiation dose of (720 +/- 80) cGy. According to a mixed ANOVA analysis, there was a trend toward a significant difference between the radiation dose absorbed by individual tumors for PR patients and that for CR patients. When the radiation dose depended on only the patient response, the p value was 0.04. When the radiation dose depended on the pre-therapy volume of the individual tumor as well as on the patient response, the p value was 0.06. Since the patient response was complete in 75% of the patients, the analysis of the total cohort of 55 evaluable patients is needed to have a larger number of PR patients to better test the trend toward a significant difference. A pseudo-prediction analysis for patient-level dose and response was also carried out. The positive predictive value and the negative predictive value were 73% and 80%, respectively when a patient's average radiation dose was used. The predictive values were 73% and 60%, respectively, when the patient's average base-10 logarithm of radiation dose was used. A complete overlap for the dose range of CR patients compared to that for PR patients precluded higher predictive values. In conclusion, there was a trend toward a significant difference in the radiation dose between CR and PR patients, but it was only moderately predictive of response.

Safety and efficacy of mangafodipir trisodium (MnDPDP) injection for hepatic MRI in adults: results of the U.S. multicenter phase III clinical trials (safety)

The short-term safety of mangafodipir trisodium (MnDPDP) injection was studied in 546 adults with known or suspected focal liver lesions. An initial contrast-enhanced computed tomography examination was followed by unenhanced magnetic resonance imaging (MRI), injection of MnDPDP (5 micromol/kg), and enhanced MRI. Adverse events were reported for 23% of the patients; most were mild to moderate in intensity, did not require treatment, and were not drug related. The most commonly reported adverse events were nausea (7%) and headache (4%). The incidence of serious adverse events was low (nine events in six patients) and not drug related. Injection-associated discomfort was reported for 69% of the patients, and the most commonly reported discomforts included heat (49%) and flushing (33%). Changes in laboratory values and vital signs were generally transient, were not clinically significant, and did not require treatment. There were no clinically significant short-term risks from exposure to MnDPDP.

Comparison of nephrographic with excretory phase helical computed tomography for detecting and characterizing renal masses

OBJECTIVE

A retrospective study was performed to compare nephrographic phase (NP) with excretory phase (EP) renal helical computed tomographic (CT) images with respect to detection of renal masses 10 mm or more in diameter, and reviewer confidence in mass characterization.

METHODS

Two reviewers evaluated 39 renal helical CT examinations. All masses measuring 10 mm or more in maximal diameter were classified as simple cysts, complex cysts, solid lesions, or indeterminate lesions. Reviewers graded their confidence in the characterization of the masses and decided whether the NP or EP contrast-enhanced images were superior.

RESULTS

The 2 reviewers confidently characterized 71 (reviewer 1) and 65 (reviewer 2) of 72 detected masses 10 mm or more in diameter on NP images and 70 (reviewer 1) and 67 (reviewer 2) of 71 detected masses on EP images. There was strong agreement between the 2 sets of images in respect to the characterization of renal masses (kappa = 1.00 and 0.86). Only one mass (a focus of acute pyelonephritis) was not detected by either reviewer on EP images. Collecting system artifact degraded the quality of the EP image in images from only 1 patient.

CONCLUSION

Although EP images are often aesthetically inferior to NP images, use of EP images results in a similar rate of detection and confidence in characterization of renal masses measuring 10 mm or more in diameter.

Crohn's disease evaluation: comparison of contrast-enhanced MR imaging and single-phase helical CT scanning

The purpose of this study was to evaluate the use of gadolinium and barium-enhanced magnetic resonance (MR) imaging in detecting intestinal and extraintestinal Crohn's disease and compare MRI with contrast-enhanced helical computed tomography (CT). Twenty-six patients with Crohn's disease underwent imaging examinations, including gadolinium-enhanced, fat suppressed fast multiplanar spoiled gradient-recalled (FMPSPGR) MR imaging with oral 2% barium sulfate and rectal water and with helical CT using i.v. and positive (13) or negative (13) intestinal contrast material. MR images and CT scans were reviewed separately by two radiologists for bowel wall thickness and enhancement, presence of abscess, phlegmon, and fistula. MR images and CT scans were then compared side by side. Surgical, endoscopic, and histopathologic findings and results of barium studies were reviewed to determine the location and severity of involvement of intestinal Crohn's disease. Depiction of mural thickening and/or enhancement was superior on the MR images, which showed 55 (85%) and 52 (80%) of 65 abnormal bowel segments for the two observers, compared with helical CT, which showed 39 (60%) and 42 (65%; P < 0.001, P < 0.05) of bowel segments affected by Crohn's disease. Segments of bowel with moderate or marked mural thickening were depicted equally on MR imaging and helical CT. In mildly diseased segments of bowel, with only slight thickening and enhancement, MR imaging depicted 22 (79%) and 19 (68%) of 28 segments, compared with helical CT, which depicted 9 (32%; P < 0.01), and 13 (46%; P > 0.05) of 28 segments. In the side-by side comparison, MR imaging was preferred over helical CT for depicting normal bowel wall (MR 71%, CT 4%, equal 25%; P < 0.001), mural thickening (MR 41%, CT 11% equal 48%; P < 0.01), mural enhancement (MR 89%, equal 11%; P < 0.001), and overall GI tract evaluation (MR 52%, CT 10%, equal 38%; P < 0.001). Gadolinium-enhanced MR imaging with oral dilute barium sulfate and rectal water depicts intestinal and extraintestinal changes of Crohn's disease and shows promise as a clinically useful tool.

CT of recurrent retroperitoneal sarcomas

OBJECTIVE

We reviewed the medical records and CT scans of 33 patients with recurrent retroperitoneal sarcomas to determine the patterns of recurrent disease.

MATERIALS AND METHODS

We reviewed the medical records and CT examinations obtained at the time the recurrence was diagnosed and tabulated data for all patients. Data for patients with high-grade malignancies were compared with those of patients with low-grade malignancies to determine whether there were differences in the interval between initial tumor resection and recurrence. We also compared CT appearances to determine patterns of recurrent disease.

RESULTS

Twenty-five of 33 recurrences were detected within 2 years of initial surgery. Only 16 patients had symptoms, and when present, most symptoms were nonspecific. In 28 (85%) patients, recurrent tumor was in the abdomen at the time of diagnosis. In nine patients, the largest detectable abdominal tumor was less than 5 cm in diameter. Interval to recurrence was similar for patients with low- and high-grade tumors. Although the CT appearance was similar for both grades, distant metastases were identified only in patients with high-grade malignancies.

CONCLUSION

Primary retroperitoneal malignancies frequently recur within 2 years of initial surgical resection. For asymptomatic patients, diagnosis is typically made during routine follow-up CT. Most patients have abdominal recurrences that may be small when first detected.

Crohn's disease evaluation: comparison of contrast-enhanced MR imaging and single-phase helical CT scanning

The purpose of this study was to evaluate the use of gadolinium and barium-enhanced magnetic resonance (MR) imaging in detecting intestinal and extraintestinal Crohn's disease and compare MRI with contrast-enhanced helical computed tomography (CT). Twenty-six patients with Crohn's disease underwent imaging examinations, including gadolinium-enhanced, fat suppressed fast multiplanar spoiled gradient-recalled (FMPSPGR) MR imaging with oral 2% barium sulfate and rectal water and with helical CT using i.v. and positive (13) or negative (13) intestinal contrast material. MR images and CT scans were reviewed separately by two radiologists for bowel wall thickness and enhancement, presence of abscess, phlegmon, and fistula. MR images and CT scans were then compared side by side. Surgical, endoscopic, and histopathologic findings and results of barium studies were reviewed to determine the location and severity of involvement of intestinal Crohn's disease. Depiction of mural thickening and/or enhancement was superior on the MR images, which showed 55 (85%) and 52 (80%) of 65 abnormal bowel segments for the two observers, compared with helical CT, which showed 39 (60%) and 42 (65%; P < 0.001, P < 0.05) of bowel segments affected by Crohn's disease. Segments of bowel with moderate or marked mural thickening were depicted equally on MR imaging and helical CT. In mildly diseased segments of bowel, with only slight thickening and enhancement, MR imaging depicted 22 (79%) and 19 (68%) of 28 segments, compared with helical CT, which depicted 9 (32%; P < 0.01), and 13 (46%; P > 0.05) of 28 segments. In the side-by side comparison, MR imaging was preferred over helical CT for depicting normal bowel wall (MR 71%, CT 4%, equal 25%; P < 0.001), mural thickening (MR 41%, CT 11% equal 48%; P < 0.01), mural enhancement (MR 89%, equal 11%; P < 0.001), and overall GI tract evaluation (MR 52%, CT 10%, equal 38%; P < 0.001). Gadolinium-enhanced MR imaging with oral dilute barium sulfate and rectal water depicts intestinal and extraintestinal changes of Crohn's disease and shows promise as a clinically useful tool.

Radiologic staging of lung cancer

Preoperative tumor staging in patients with known or suspected non-small cell lung cancer is generally performed using contrast enhanced chest computed tomography (CT) (including the adrenal glands). Abdominal CT is generally unnecessary, given the low frequency of isolated liver metastases. The role of MRI is limited, and it is used mainly as a problem solving tool in certain specific situations. A CT showing no mediastinal lymph node enlargement usually oviates preoperative mediastinal lymph node sampling, with certain exceptions. If enlarged mediastinal lymph nodes are demonstrated at CT, then CT may be used to direct preoperative lymph node sampling via transbronchoscopic Wang needle biopsy, mediastinoscopy, mediastinotomy, or video assisted thoracoscopy.

I-131 anti-B1 therapy/tracer uptake ratio using a new procedure for fusion of tracer images to computed tomography images

In patients with non-Hodgkin's lymphoma being treated by I-131-radiolabeled anti-B1 monoclonal antibody, we test the hypothesis that the activity taken up in tumors during therapy is the same as that observed during tracer evaluation, except for scaling by the ratio of administered activities. Chemotherapy-relapsed patients are imaged only with planar conjugate views, whereas previously untreated patients are imaged with planar conjugate views and with single-photon emission computed tomography (SPECT). The SPECT tracer activity quantification requires computed tomography (CT) to SPECT image fusion, for which we devised a new procedure: first, the tracer SPECT images are fused to the therapy SPECT images. Then, that transformation is combined with the therapy SPECT-to-CT transformation. We also use (a) the same volumes of interest defined on CT for both tracer and therapy image sets, and (b) a SPECT counts-to-activity conversion factor that adapts to background and rotation radius. We define R as the ratio of therapy activity percentage of infused dose over tracer activity percentage of infused dose at 2-3 days after monoclonal antibody infusion. For 31 chemotherapy-relapsed patients, the R ratio for 60 solitary or composite tumors averages 0.931 +/- 0.031. The hypothesis of R being 1 is rejected with greater than 95% confidence. However, the difference from 1 is only 7.4%. The range of R is 0.43-1.55. For seven previously untreated patients, R averages 1.050 +/- 0.050 for 24 solitary tumors evaluated by SPECT. For six of these patients, R averages 0.946 +/- 0.098 for one of these solitary tumors and for five composite tumors, evaluated by conjugate views. Both results agree with the hypothesis that R is 1. The range of R for the SPECT tumors is 0.71 +/- 0.03 to 1.82 +/- 0.53, and for the conjugate view tumors, it is 0.70-1.35. Plots of R versus tumor volume yield small correlation coefficients. That from SPECT approaches a statistically significant difference from zero correlation (P = 0.06). In summary, on average, the tumor percentage of infused dose following tracer administration is predictive of therapeutic percentage of infused dose within 8%. For greater accuracy with individual tumors, however, an intratherapy evaluation is probably necessary because the range of R is large.

Pheochromocytomas: imaging with 2-[fluorine-18]fluoro-2-deoxy-D-glucose PET

PURPOSE

To assess the sensitivity of positron emission tomography (PET) with 2-[fluorine-18]fluoro-2-deoxy-D-glucose (FDG) in pheochromocytomas and, secondarily, to compare images obtained with FDG PET to those obtained with metaiodobenzylguanidine (MIBG) scintigraphy.

MATERIALS AND METHODS

Twenty-nine patients with one or more known or subsequently proved pheochromocytomas underwent FDG PET (35 scans) and MIBG scintigraphy (35 scans). Tumor uptake of FDG was quantified on positive PET scans.

RESULTS

Tumor uptake of FDG was detected in 22 of 29 patients. Most benign (seven of 12 patients) and most malignant (15 of 17 patients) pheochromocytomas and their metastases avidly concentrated FDG. In four patients whose pheochromocytomas failed to accumulate MIBG, uptake of FDG in the tumors was intense. For the majority of the 16 patients whose tumors concentrated both agents, however, ratings for MIBG images compared to FDG PET images for delineation of the tumor in comparison to background and normal organ accumulation were superior for nine patients (56%) and as good or better for 14 (88%).

CONCLUSION

Most pheochromocytomas accumulate FDG. Uptake is found in a greater percentage of malignant than benign pheochromocytomas. FDG PET is especially useful in defining the distribution of those pheochromocytomas that fail to concentrate MIBG.

Diagnosis and staging of ovarian cancer: comparative values of Doppler and conventional US, CT, and MR imaging correlated with surgery and histopathologic analysis--report of the Radiology Diagnostic Oncology Group

PURPOSE

To determine the optimal imaging modality for diagnosis and staging of ovarian cancer.

MATERIALS AND METHODS

Two hundred eighty women suspected to have ovarian cancer were enrolled in a prospective study before surgery. Doppler ultrasonography (US), computed tomography (CT), and magnetic resonance (MR) imaging were used to evaluate the mass; conventional US, CT, and MR imaging were used to stage spread.

RESULTS

All three modalities had high accuracy (0.91) for the overall diagnosis of malignancy. In the ovaries, the accuracy of MR imaging (0.91) was higher than that of CT and significantly higher than that of Doppler US (0.78). In the extraovarian pelvis and in the abdomen, conventional US, CT, and MR imaging had similar accuracies (0.87-0.95). In differentiation of disease confined to the pelvis from abdominal spread, the specificity of conventional US (96%) was higher than that of CT and significantly higher than that of MR imaging (88%), whereas the sensitivities of MR imaging (98%) and CT (92%) were significantly higher than that of conventional US (75%).

CONCLUSION

MR imaging is superior to Doppler US and CT in diagnosis of malignant ovarian masses. There is little variation among conventional US, CT, and MR imaging as regards staging.

Orthotopic neobladder reconstruction: findings on excretory urography and CT

OBJECTIVE

The excretory urographic and CT appearance of orthotopic ileal neobladder reconstruction after cystectomy and its complications are described.

MATERIALS AND METHODS

We retrospectively reviewed the excretory urograms and CT scans of 32 patients (29 men and three women, 35-76 years old) with transitional cell carcinoma of the bladder who underwent orthotopic neobladder reconstruction with anastomosis to the native urethra after cystectomy. The radiologic review consisted of 25 excretory urograms in 20 patients and 37 CT scans in 21 patients.

RESULTS

On excretory urography, the afferent segment of the neobladder was identified as a contrast-filled structure in all 20 patients, and was located in the right lower quadrant in 18 (90%). On CT, the afferent segment and the neobladder were identified in all 21 patients. Delayed imaging performed after initial scanning in 12 (57%) of 21 patients was helpful for revealing detailed anatomy such as the ureteral-afferent limb anastomoses. Complications occurred in two patients and were caused by a lymphocele in one and a urine leak from the neobladder in the other. In six other patients we found evidence of recurrent or metastatic tumor or both: two had local pelvic recurrence and pelvic nodal metastases, two other patients had metastatic nodal disease, one patient had a malignant distal ureteral stricture, and the sixth patient had distant osseous metastases.

CONCLUSION

Orthotopic neobladder reconstruction after cystectomy has a characteristic appearance on both excretory urography and CT. Knowledge of this appearance and the altered anatomy is useful to recognize complications and tumor recurrence. Delayed images during excretory urography and CT are useful to define the ureteral-afferent limb anastomosis with the neobladder and also to differentiate between postoperative collections.

Synthetic interposition grafts of the thoracic aorta: postoperative appearance on serial CT studies

PURPOSE

To determine the normal postoperative appearance of thoracic aortic interposition grafts on serial CT studies and to document CT detectable complications.

MATERIALS AND METHODS

The 235 CT studies in 114 patients with one or more thoracic aortic interposition grafts were analyzed for the presence or absence of felt rings, felt pledgets, low-attenuation material surrounding the graft, pseudoaneurysm, and dissection flap. A graft was present in the ascending aorta in 93 patients, in the descending aorta in 25, and in the arch in 11.

RESULTS

Low-attenuation material was seen adjacent to the ascending graft in 55%-82% of patients and adjacent to the descending graft in 60%-79% of patients, showing diminishing frequency and thickness over time. CT scans in 30 of 53 patients showed residual low-attenuation material adjacent to the graft more than 1 year after surgery. CT scans in four of 93 patients with ascending grafts and one of 25 patients with descending grafts showed a pseudoaneurysm.

CONCLUSION

CT studies obtained after aortic interposition grafting show characteristic findings. Knowledge of the type of operative procedure and typical location and CT appearance of surgical materials used is important to correctly diagnose or exclude postoperative complications following thoracic aortic interposition grafting.

Germ cell tumor: differentiation of viable tumor, mature teratoma, and necrotic tissue with FDG PET and kinetic modeling

PURPOSE

To evaluate the feasibility of positron emission tomography (PET) with 2-[fluorine-18]-fluoro-2-deoxy-D-glucose (FDG) in patients with germ cell tumor (GCT) to monitor treatment and differentiate residual masses after chemotherapy.

MATERIALS AND METHODS

Twenty-six FDG PET studies were performed in 21 patients with GCT, FDG uptake of tumors was interpreted visually, and the lean standardized uptake value (SUVlean) was determined. Tumor kinetic rate constants (K1, k2, k3) and net rate of FDG phosphorylation (K = [K1.k3]/[k2 + k3]) in tumors were calculated from the dynamic data by means of a three-compartment model, assuming k4 = 0.

RESULTS

Viable tumors (n = 10) showed intense FDG uptake and could easily be differentiated visually from mature teratoma (n = 6) and necrosis or scar (n = 10). The SUVlean of residual viable tumors (4.51 +/- 1.34 [mean +/- SD]) was higher than that of mature teratoma (1.38 +/- 0.71) and necrosis or scar (1.05 +/- 0.29) (P < .05). Although neither the visual interpretation nor SUVlean differentiated mature teratoma from necrosis or scar, there were statistically significant differences in the kinetic rate constants K1 and K between mature teratoma and necrosis or scar as follows: K1, 0.113 mL/min/g +/- 0.026 versus 0.036 mL/min/g +/- 0.005 (P < .05); K, 0.005 mL/min/g +/- 0.003 versus 0.0008 mL/min/g +/- 0.0001 (P < .05).

CONCLUSION

FDG PET with kinetic analysis appears to be a promising method for management of disease in patients with GCT after treatment.

CT appearance of primary papillary serous carcinoma of the peritoneum

OBJECTIVE

Our objective was to describe the CT characteristics of primary papillary serous carcinoma of the peritoneum.

CONCLUSION

The presence of peritoneal masses, extensive omental calcification, and the absence of an ovarian mass on CT--particularly in postmenopausal women--is highly suggestive of primary papillary serous carcinoma of the peritoneum and should alert the radiologist to the possibility of this diagnosis.

Complete spontaneous regression of pulmonary metastatic melanoma

BACKGROUND

Complete spontaneous regression of melanoma metastatic to the lungs is a rare event.

OBJECTIVE

To report a case of biopsy-proven melanoma metastatic to the lung with complete spontaneous regression.

METHODS

Multidisciplinary case report.

RESULTS

A 35-year-old white female was diagnosed with metastatic melanoma to the lung. A pleural biopsy confirmed the diagnosis. Partial spontaneous regression was noted by a staging computed tomography scan prior to enrollment in an investigational protocol. Complete spontaneous regression occurred over 5 months without any form of conventional or alternative therapy, and the patient remains disease-free 3 years after diagnosis.

CONCLUSIONS

Our case represents the seventh case of complete spontaneous regression of melanoma metastatic to the lung, and the only case with histologic confirmation of both the primary and pulmonary metastatic lesions. The patient was pregnant twice between the time of her initial diagnosis of primary melanoma and pulmonary metastatic disease.

Iodine-131 anti-B1 antibody for B-cell lymphoma: an update on the Michigan Phase I experience

Iodine-131 anti-B1 antibody radioimmunotherapy for B-cell lymphoma was previously reported to have substantial antitumor activity in B-cell non-Hodgkin's lymphoma (NHL) after failures of standard and salvage chemotherapy. In this article, the University of Michigan Phase I clinical experience is updated, with follow-up of up to 6 yr since initial treatment reported.

METHODS

Thirty-four patients with CD20-expressing NHL were first studied with one or more dosimetric doses of approximately 5 mCi of 1311 anti-B1 antibody (after varying predoses of unlabeled anti-B1 antibody). They were then treated with a patient-specific radioimmunotherapeutic dose designed to deliver a specified radiation dose to the whole body of between 25 and 85 cGy. Patients were observed for toxicity and tumor response.

RESULTS

Seventeen (50%) patients had low-grade NHL, 9 (26%) had low-grade transformed NHL and 8 (24%) had de novo intermediate-grade NHL. At study entry, 17 (50%) had an elevated lactate dehydrogenase level, 12 (35%) had high tumor burden and 18 (53%) had not responded to their last chemotherapy. The median number of prior NHL therapies was 4.1. Twenty-eight of 34 patients completed treatment, with 22 of 28 (79%) achieving a response and 14 of 28 (50%) achieving a complete response (CR). The median duration of response was 357 days. The median duration of response for CRs was 471 days, with 4 CRs having a duration of > 1000 days (maximum = > 1460 days). Bone marrow toxicity was dose-limiting and dependent on the total-body dose (TBD) of radiation. Thrombocytopenia appeared to be more marked in patients with prior bone marrow transplantation. The TBD of 75 cGy was established as the maximum tolerated dose in patients who had not had prior bone marrow transplantation. Duration of CR was significantly longer (p < 0.04) in patients who received a TBD of 65-75 cGy (1109 days) than it was in those who received a lower TBD of 25-60 cGy (385 days). Four of 34 (12%) patients developed detectable human antimouse antibody levels. The median survival from study entry for all patients was 1508 days (range = 63 to >2226 days). Sixteen of 17 patients who achieved a response of > or = 6 mo duration remain alive.

CONCLUSION

This update of the Phase I results after 1311 anti-B1 antibody treatment for NHL indicates that CRs can be durable and that survival can be of long duration. This form of therapy for NHL should have increasing application in clinical practice after confirmation of these results in larger multicenter studies.

High prevalence of thymic tissue in adults with human immunodeficiency virus-1 infection

The thymus in adults infected with the HIV-1 is generally thought to be inactive, both because of age-related involution and viral destruction. We have revisited the question of thymic function in adults, using chest-computed tomography (CT) to measure thymic tissue in HIV-1-seropositive (n = 99) or HIV-1-seronegative (n = 32) subjects, and correlating these results with the level of circulating CD4(+) and CD8(+) T cells that are phenotypically described as naive thymic emigrants. Abundant thymic tissue was detectable in many (47/99) HIV-1-seropositive adults, aged 20-59. Independent of age, radiographic demonstration of thymic tissue was significantly associated with both a higher CD4(+) T cell count (P = 0.02) and a higher percentage and absolute number of circulating naive (CD45RA+CD62L+) CD4(+) T cells (P < 0.04). The prevalence of an abundant thymus was especially high in younger HIV-1-seropositive adults (</= 39 yr) with CD4 counts in the range 300-500 cells/microl and in older subjects (> 40 yr) regardless of CD4 count (P = 0.03). These studies suggest that the thymus is functional in some but not all adults with HIV-1 disease.

Variability in the detection of enlarged mediastinal lymph nodes in staging lung cancer: a comparison of contrast-enhanced and unenhanced CT

OBJECTIVE

Because CT protocols for staging lung cancer vary and little information exists regarding the diagnostic importance of using i.v. contrast material, our intent was to evaluate intra- and interobserver agreement in the detection of enlarged mediastinal lymph nodes, comparing i.v. contrast-enhanced and unenhanced CT.

SUBJECTS AND METHODS

Fifty patients with known or suspected bronchogenic carcinoma underwent unenhanced thoracic CT followed by contrast-enhanced CT. Three observers noted enlarged lymph nodes (> 10 mm in the short axis) and assigned the enlarged nodes to American Thoracic Society nodal station designations. Enlarged lymph nodes were grouped two ways: by assigning the exact number of enlarged lymph nodes found (zero, one, two, three, four or more), and by assigning whether at least one, or no, enlarged mediastinal lymph nodes were found at a station ("one or none"). Agreement levels were determined for inter- and intraobserver interpretations using weighted kappa statistics and the McNemar test.

RESULTS

The number of enlarged lymph nodes with enhanced CT was 11% higher than on unenhanced studies (418 versus 377; p = .044). Numbers of enlarged lymph nodes were different for five stations; however, the numbers were small except for the right upper paratracheal station (2R) (contrast-enhanced, 68 enlarged lymph nodes; unenhanced, 44 enlarged lymph nodes; p = .014). With regard to all stations together, intraobserver agreement between contrast-enhanced and unenhanced studies was almost perfect (kappa range, .85-.94), and no difference was found for any observer in the proportion of patients with at least one enlarged lymph node. Interobserver agreement was substantial or almost perfect for the total number of enlarged lymph nodes. For specific stations, the lowest kappa value was .48 at 2R. One observer reported more patients with at least one enlarged lymph node with contrast enhancement at station 2R (p = .031). Greater agreement existed between two observers at station 2R with contrast enhancement versus no enhancement (kappa = .85 versus .48; p = .02). Conclusions matched, and calculations of estimated kappa values gave similar results for determination of the specific number of enlarged lymph nodes at a station and the "one or none" category.

CONCLUSION

We found high agreement for intra- and interobserver interpretations for contrast-enhanced and unenhanced CT, although contrast-enhanced CT revealed more enlarged lymph nodes, especially at station 2R.

Diagnostic evaluation of the adrenal incidentaloma: decision and cost-effectiveness analyses

The goal of this study was to examine the clinical and economic outcomes of alternative diagnostic strategies for differentiating benign from malignant adrenal masses.

METHODS

We used cost-effectiveness assessment derived from decision analysis and the economic perspective of the payer of health care services. One-time evaluation with fine-needle aspiration (FNA) and combinations of chemical-shift MRI, noncontrast CT, 131I-6beta-iodomethylnorcholesterol (NP-59) scintigraphy, with or without FNA, in a hypothetical cohort of 1000 patients with incidentally discovered unilateral, nonhypersecretory adrenal masses. We calculated and compared the diagnostic effectiveness, costs and cost-effectiveness of the alternative strategies based on estimates from published literature and institutional charge data.

RESULTS

At an assumed baseline malignancy rate of 0.25, diagnostic utility varied from 0.31 (CT0) to 0.965 (NP-59) and diagnostic accuracy from 0.655 [noncontrast CT using a cut-off attenuation value of > or = 0 (CT0)] to 0.983 (NP-59). The average cost per patient per strategy ranged from $746 (NP-59) to $1745 (MRI +/- FNA). The best and worst potential cost-to-diagnostic utility ratios were 773 (NP-59) and 2839 (CT0) and 759 (NP-59) and 1982 (MRI +/- FNA) for cost and diagnostic accuracy, respectively. The NP-59 strategy was the optimal choice regardless of the expected outcome examined: cost, diagnostic utility, diagnostic accuracy or cost-effectiveness. Varying the prevalence of malignancy did not alter the cost-effectiveness advantage of NP-59 over the other diagnostic modalities.

CONCLUSION

Based on available estimates of reimbursement costs and diagnostic test performance and using reasonable clinical assumptions, our results indicate that the NP-59 strategy is the most cost-effective diagnostic tool for evaluating adrenal incidentalomas over a wide range of malignancy rates and that additional clinical studies are warranted to confirm this cost-effectiveness advantage.

CT time-attenuation washout curves of adrenal adenomas and nonadenomas

OBJECTIVE

The purpose of this study was to analyze the CT contrast enhancement washout curves of adrenal masses and to determine the earliest time after initial enhancement that differentiation of adenomas from nonadenomas is possible.

MATERIALS AND METHODS

Contrast enhancement washout curves were generated after delayed contrast-enhanced CT scans of 52 adrenal adenomas and 24 nonadenomas. The optimal threshold value and corresponding sensitivity and specificity for the diagnosis of adenoma were determined according to attenuation values. Also, we calculated the percentage and relative percentage of enhancement washout at time delays from 5 to 45 min after initial enhancement.

RESULTS

The mean percentage of enhancement washout for adrenal adenomas was 51% at 5 min and 70% at 15 min, compared with 8% and 20%, respectively, for nonadenomas. The sensitivity and specificity for the diagnosis of adenoma were both 96% at a threshold attenuation value of 37 H on the 15-min delayed enhanced scan.

CONCLUSION

On CT, adrenal adenomas show a much earlier and more rapid washout of contrast enhancement than do nonadenomas. Adenomas and nonadenomas can be differentiated by attenuation values or the percentage or relative percentage of washout as early as 5-15 min after enhancement.

Dual-phase helical CT of nonfunctioning islet cell tumors

PURPOSE

The aim of this study was to evaluate the utility of dual-phase imaging in the assessment of nonfunctioning islet cell tumors (NFITs).

METHOD

Six patients with histologically and biochemically proven NFIT were evaluated by arterial and portal venous dual-phase helical CT. Scan delay was 20 s for the arterial phase and 70 s for the portal phase. Each phase was assessed by consensus reading and specifically evaluated for tumor conspicuity, hepatic metastases, vascular encasement by tumor, and presence of lymphadenopathy.

RESULTS

Overall, tumor conspicuity was greater in the arterial phase (5/6) than in the portal venous phase (1/6) with a mean tumor/normal pancreas attenuation difference of 31.8 HU in the arterial phase compared with 19.2 HU in the portal venous phase. The arterial phase detected a total of 17 liver metastases compared with 9 seen in the portal phase. Lymph node enlargement was noted in three patients, which, although visible in both phases, was more easily discernible in the arterial phase. Venous encasement by tumor was better evaluated on the delayed portal venous phase than the arterial phase.

CONCLUSION

Dual-phase helical CT scanning leads to improvement in the detection and staging of NFITs.

CT appearance of sclerosing peritonitis in patients on chronic ambulatory peritoneal dialysis

PURPOSE

The purpose of this study was to describe the CT appearances of sclerosing peritonitis (SP) in patients on chronic ambulatory peritoneal dialysis (CAPD) and to compare these findings with the CT appearances in a control group of CAPD patients who did not develop SP.

METHOD

The CT findings in 10 patients with SP were compared with those from a "control group" of 71 patients without SP who were on long-term CAPD and had also undergone at least one CT examination. Particular reference on CT examination was made to the appearance of the peritoneum and small bowel and the presence or absence of loculated fluid collections.

RESULTS

Peritoneal abnormalities (calcification/thickening) were noted in 100%, loculated fluid collections in 90%, and small bowel abnormalities (tethering/dilatation) in 60% of the patients with SP. In the control group of patients, peritoneal abnormalities were noted in only 7%, loculated fluid collections in 15%, and small bowel dilatation in 5.7%.

CONCLUSION

Peritoneal thickening, peritoneal calcification, loculated fluid collections, and tethering of the small bowel appear to be diagnostic of SP. In a small group of patients with follow-up CT scans, new, or progression of, CT findings correlated with the clinical severity of SP.

Dual-phase helical CT of nonfunctioning islet cell tumors

PURPOSE

The aim of this study was to evaluate the utility of dual-phase imaging in the assessment of nonfunctioning islet cell tumors (NFITs).

METHOD

Six patients with histologically and biochemically proven NFIT were evaluated by arterial and portal venous dual-phase helical CT. Scan delay was 20 s for the arterial phase and 70 s for the portal phase. Each phase was assessed by consensus reading and specifically evaluated for tumor conspicuity, hepatic metastases, vascular encasement by tumor, and presence of lymphadenopathy.

RESULTS

Overall, tumor conspicuity was greater in the arterial phase (5/6) than in the portal venous phase (1/6) with a mean tumor/normal pancreas attenuation difference of 31.8 HU in the arterial phase compared with 19.2 HU in the portal venous phase. The arterial phase detected a total of 17 liver metastases compared with 9 seen in the portal phase. Lymph node enlargement was noted in three patients, which, although visible in both phases, was more easily discernible in the arterial phase. Venous encasement by tumor was better evaluated on the delayed portal venous phase than the arterial phase.

CONCLUSION

Dual-phase helical CT scanning leads to improvement in the detection and staging of NFITs.

Radiation following chemotherapy for mediastinal Hodgkin's disease: the outcome of various doses for bulky tumors

Twenty-one patients with bulky mediastinal disease responding to chemotherapy received consolidation with low-dose mediastinal radiation (19.8-25.2 Gy). Their 5-year mediastinal failure rate (10%) was equivalent to that of 10 similar patients who received higher doses of 30-44 Gy (20%). Low-dose radiation may be appropriate for these patients. Prospective studies are required to verify these findings.

Local reactions after injection of iodinated contrast material: detection, management, and outcome

RATIONALE AND OBJECTIVES

The authors assessed the frequency, sequelae, and risk factors of extravasation of intravenously administered iodinated contrast media.

MATERIALS AND METHODS

All patients with local reactions after intravenous injection of contrast media between November 1994 and December 1996 were studied. Comparison was made with data obtained from a control group of 100 patients with no local reactions who underwent contrast material-enhanced computed tomography (CT).

RESULTS

Local reactions were reported in 56 (0.25%) of 22,254 patients who received intravenous injections of iodinated contrast media. Fifty-one patients experienced extravasation, and five patients experienced local irritation in the absence of clinically detectable extravasation. Extravasation occurred during CT (n = 46), urography (n = 4), and venography (n = 1). Contrast material was nonionic in 37 cases and conventional ionic in 14 cases of extravasation. Extravasated volumes exceeded 30 mL in 22 patients and 100 mL in six patients. Forty-five (80%) of 56 patients with local reactions had complete resolution of symptoms within 24 hours. Only four patients had symptoms for more than 48 hours. No surgery was required. Compared with the control group, patients with extravasation were significantly more likely to have been injected with small-bore catheters (21 or 22 gauge) and to have been injected at low or high rates.

CONCLUSION

Symptoms of contrast medium extravasation usually resolve quickly. In patients with extravasation, injections are more likely to have been performed with techniques that vary from normal practice.

Liver metastases: early detection based on abnormal contrast material enhancement at dual-phase helical CT

PURPOSE

To assess whether contrast material enhancement findings on computed tomographic (CT) scans are useful in determination of the risk for development of hepatic metastases.

MATERIALS AND METHODS

Dual-phase helical CT scans were obtained in 80 patients with nonhepatic cancer and no hepatic metastases visible at CT. Attenuation was measured on scans obtained at 25 and 40 seconds. Peak liver attenuation was determined in all cases. Unenhanced scans were obtained in 35 patients. The ratio of liver attenuation at 25 and 40 seconds to peak liver attenuation, liver enhancement values at 25 and 40 seconds, and ratio of liver enhancement at 25 and 40 seconds to peak liver enhancement were determined.

RESULTS

Liver metastases developed during 18-month follow-up in 22 patients. The 25- and 40-second liver enhancement values and the liver enhancement and attenuation ratios were higher in these patients than in those who did not develop metastases (P < .01). Enhancement values and ratios were more accurate than densitometric measurements for predicting development of metastases. Use of an optimal threshold (0.40 or greater) for the 40-second enhancement ratio resulted in a sensitivity of 75%, specificity of 96%, and overall accuracy of 89%.

CONCLUSION

CT measurements may help in the prediction of risk for subsequent development of hepatic metastases.

MR imaging of the gastrointestinal tract with i.v., gadolinium and diluted barium oral contrast media compared with unenhanced MR imaging and CT

OBJECTIVE

To determine an optimal MR imaging technique and pulse sequence for evaluating mural and serosal disease of the gastrointestinal tract, we administered 2% oral barium sulfate and obtained fat-suppressed gadolinium-enhanced breath-hold fast multiplanar spoiled gradient-recalled (FMPSPGR) MR images. We then compared these images with spin-echo T1-weighted and T2-weighted fast spin-echo MR images and with CT images.

SUBJECTS AND METHODS

Thirty-one patients with suspected diseases of the gastrointestinal tract were imaged with spin-echo T1-weighted, fast spin-echo T2-weighted, and fat-saturated gadolinium-enhanced FMPSPGR MR imaging. Before undergoing MR imaging, all patients received 1350 ml of 2% barium sulfate oral contrast media. For CT scans, patients received 120 ml of iodinated i.v. contrast material and 2% barium sulfate oral contrast material. CT and MR images were retrospectively and independently reviewed by two radiologists for ability to see normal bowel wall, for the presence of abnormal gastrointestinal tract mural thickening or enhancement, and for overall gastrointestinal tract visualization. Findings were correlated with surgical findings, endoscopy, and barium studies.

RESULTS

Ten patients had benign disease, 16 had malignant gastrointestinal tract disease, and five had no gastrointestinal tract abnormalities. In 94% of patients, the gadolinium- and barium-enhanced FMPSPGR MR images were superior to CT and spin-echo MR sequences for depicting the wall of the normal bowel (p < .001). For the two observers, the FMPSPGR MR images with i.v. and oral contrast material were seen as revealing 94% and 95% of bowel segments with malignant or inflammatory mural thickening or serosal tumor. In comparison, CT revealed 64% and 72% (p < .01 and p < .0001, respectively), fast spin-echo T2-weighted MR images revealed 21% and 28% (p < .0001), and T1-weighted MR images revealed 17% and 18% (p < .0001). The gadolinium- and barium-enhanced MR images were preferred for overall gastrointestinal tract visualization in 65% of patients compared with 1% for CT scans (p < .001). In 32% of patients, the enhanced MR images were equivalent to CT images.

CONCLUSION

MR evaluation of the gastrointestinal tract requires bowel distention with oral contrast material as well as motion reduction techniques, including glucagon and rapid gradient-echo pulses that allow breath-hold imaging. Fat-suppressed gadolinium-enhanced FMPSPGR MR imaging with diluted barium oral contrast media is effective for imaging benign and malignant mural and serosal abnormalities of the gastrointestinal tract.

Imaging of adrenal masses

Most adrenal masses are detected on CT scans, but only a minority has morphologic features that are characteristic of a specific histologic diagnosis. In patients with clinical or biochemical features of a hyperfunctioning adrenal syndrome, CT detection of a unilateral adrenal mass typically leads to surgical resection, although functional assessment of the mass with iodomethylnorcholesterol or MIBG scintigraphy sometimes is used to augment the CT findings. In patients with a nonhyperfunctioning adrenal mass, chemical shift MR and CT densitometry have begun to replace percutaneous adrenal biopsy or serial follow-up CT as methods to establish a specific diagnosis. In this article the authors review the clinical features and imaging findings of patients with known or suspected adrenal masses.

Difference in global hepatic enhancement assessed by dynamic CT in normal subjects and patients with hepatic metastases

PURPOSE

Our goal was to determine if there are differences in liver densitometry parameters using helical CT between normal subjects and subjects with liver metastases.

METHOD

One-hundred fifty subjects (64 with normal livers and 86 with CT-visible hepatic metastases) underwent dual phase helical scanning of the liver. Images were obtained in the "arterial" (early) and "venous" (late) phases of hepatic enhancement. Densitometry measurements were obtained from the liver (distinct from obvious lesions or vessels) and aorta at 25, 40, 75, and 90 s. Enhancement values at the same time points were calculated in 73 subjects in whom noncontrast images of the liver were available. A peak liver densitometry value was also determined. Several ratios were determined for each time point: the liver/aortic ratio (L/A), liver/liver peak ratio (L/P), liver enhancement/aortic enhancement ratio (LE/AE), and liver enhancement/liver peak enhancement ratio (LE/LPE). The degree of tumor burden in the hepatic metastatic group was assessed in each case.

RESULTS

Values for L/A, L/P, LE/AE, and LE/LPE at 25 and 40 s were significantly (p < 0.05) higher in the liver metastases group than the normal liver group. Enhancement ratios were even more elevated in breast cancer, which can have hypervascular metastases. These CT parameters did not show significant differences when analyzed according to the degree of hepatic metastatic tumor burden. All densitometry parameters and ratios obtained at 75 and 90 s were not significantly different between the two groups.

CONCLUSION

In the early phase of bolus intravenous contrast agent administration, the visually normal portion of the liver parenchyma in patients with hepatic metastases enhances to a greater degree than the liver in normal subjects. This may reflect generalized increased hepatic arterial flow in tumor-bearing livers and has the potential to increase the sensitivity of CT for detection of hepatic metastases.

Dose escalation for non-small cell lung cancer using conformal radiation therapy

PURPOSE

Improved local control of non-small cell lung cancer (NSCLC) may be possible with an increased dose of radiation. Three-dimensional radiation treatment planning (3D RTP) was used to design a radiation therapy (RT) dose escalation trial, where the dose was determined by (a) the effective volume of normal lung irradiated, and (b) the estimated risk of a complication. Preliminary results of this trial were reviewed.

METHODS AND MATERIALS

A graph of the iso-normal tissue complication probability (NTCP) levels associated with a dose and effective volume (V(eff)) was derived, using normal tissue parameters derived from the literature. This led to a dose escalation schema, where patients were sorted into 1 of 5 treatment bins, determined by the V(eff) of the best possible treatment plan. The starting doses ranged from 63 to 84 Gy. Each treatment bin was then escalated separately, as in Phase I dose escalation fashion, with Grade > or = 3 radiation pneumonitis defined as dose limiting. To allow for dose escalation, we required patient follow-up to be > or = 6 months for at least three patients. 3D treatment planning was used to irradiate only the radiographically abnormal areas, with 2.1 Gy (corrected for lung inhomogeneity)/day. Clinically uninvolved lymph nodes were not treated prophylactically.

RESULTS

A total of 48 NSCLC patients have been treated (Stage I/II: 18 patients; Stage III: 28 patients; mediastinal recurrence postsurgery: 2 patients). No radiation pneumonitis has been observed in the 30 patients currently evaluable beyond the 6-month time point. All treatment bins have been escalated at least once. Current doses in the five treatment bins are 69.3, 69.3, 75.6, 84, and 92.4 Gy. None of the 15 evaluable patients in any bin with > or = 30% NTCP experienced clinical radiation pneumonitis, implying that the actual risk is < 20% (beta error rate 5%). Despite the observation of the clinically negative lymph nodes at high risk, there has been no failure in the untreated mediastinum as the sole site of first failure. Three of 10 patients receiving > or = 84 Gy have had biopsy proven residual or locally recurrent disease.

CONCLUSION

Successful dose escalation in a volume-dependent organ can be performed using this technique. By incorporating the effective volume of irradiated tissue, some patients have been treated to a total dose of radiation over 50% higher than traditional doses. The literature-derived parameters appear to overestimate pneumonitis risk with higher volumes. There has been no obvious negative effect due to exclusion of elective lymph node radiation. When completed, this trial will have determined the maximum tolerable dose of RT as a single agent for NSCLC and the appropriate dose for Phase II investigation.

Adrenal and extra-adrenal retroperitoneal ganglioneuroma: imaging findings in 13 adults

PURPOSE

To determine the radiologic appearance of ganglioneuromas of the adrenal gland and extra-adrenal retroperitoneum.

MATERIALS AND METHODS

A retrospective review was performed of imaging findings in nine patients with ganglioneuroma, two with ganglioneuroma-pheochromocytoma, and two with malignant peripheral nerve sheath tumor (PNST) that arose in a ganglioneuroma. Patients underwent computed tomography (CT) (n = 13), magnetic resonance (MR) imaging (n = 5), and ultrasonography (US) (n = 5).

RESULTS

In nine patients with ganglioneuroma, the mass ranged in size from 2 x 4 x 4 cm to 21 x 21 x 22 cm. Imaging findings included attenuation entirely or predominantly less than that of muscle on contrast material-enhanced CT images (n = 9); heterogeneous, predominantly high signal intensity on T2-weighted MR images (n = 5); partial or complete surrounding of one or more major blood vessels with little or no luminal narrowing (n = 4) and calcifications (n = 4) on CT scans; and homogeneous, moderate echogenicity (n = 3) on US scans. CT findings in two patients with ganglioneuroma-pheochromocytoma included central necrosis (n = 1) and calcifications (n = 1). In the two patients with malignant PNST that arose in a ganglioneuroma, contrast-enhanced CT showed a large, markedly heterogeneous mass.

CONCLUSION

Diagnosis of ganglioneuroma should be considered when typical CT or MR imaging findings are present. Findings in cases of ganglioneuroma-pheochromocytoma and malignant PNST arising in a ganglioneuroma appear to be nonspecific.