Abdominal manifestations of posttransplantation lymphoproliferative disorder

The abdominal manifestations of posttransplantation lymphoproliferative disorder show wide variability with potential involvement of all organ systems. The radiologist should be aware of this entity when evaluating patients who have undergone transplantation; both clinical and radiologic findings can mimic other disease processes. Suggestive lesions should prompt a search for additional areas of involvement. In our experience, although sonography can reveal posttransplantation lymphoproliferative disorder of the abdominal viscera, CT more adequately depicts the full extent of disease involvement. Distinguishing between monomorphic and polymorphic subtypes, though important for treatment planning, is not possible by imaging characteristics alone. Therefore, tissue diagnosis is warranted.

Bronchiolitis obliterans syndrome: thin-section CT diagnosis of obstructive changes in infants and young children after lung transplantation

PURPOSE

To characterize the thin-section computed tomographic (CT) appearance of bronchiolitis fibrosa obliterans syndrome in infants and young children after lung transplantation.

MATERIALS AND METHODS

Thin-section CT studies in six patients with bronchiolitis obliterans syndrome (age range, 2 months to 5 1/2 years) and in 15 control patients without obstructive airway disease (age range, 2 months to 7 years) who underwent bilateral lung transplantation were retrospectively reviewed. The thin-section CT scans were obtained during quiet sleep at a median of 24 months (range, 6-36 months) after transplantation. The CT studies were evaluated for mosaic perfusion, bronchial dilatation, bronchial wall thickening, and mucous plugging Final diagnoses in all patients were based pulmonary function test results.

RESULTS

Thin-section CT findings in the six patients with clinically proved bronchiolitis obliterans syndrome were mosaic perfusion in five (83%) bronchial dilation in three (50%), and bronchial wall thickening in one (17%). Of the 15 control patients with normal pulmonary function test results, six (40%) had mosaic perfusion; none had bronchial dilatation or bronchial wall thickening. Mucous plugging was not seen in either group. Only the association of bronchial dilatation with bronchiolitis obliterans syndrome was significant (P = .02).

CONCLUSION

Infants and young children with bronchiolitis obliterans syndrome after lung transplantation are more likely to have CT abnormalities than those with normal pulmonary function test results.

Nonmalignant renal disease in pediatric patients with Beckwith-Wiedemann syndrome

OBJECTIVE

The objective of this retrospective review was to determine the incidence and spectrum of nonmalignant renal disease in patients with Beckwith-Wiedemann syndrome.

MATERIALS AND METHODS

Patient records were obtained from the Beckwith-Wiedemann Registry of the National Cancer Institute. Imaging findings and medical records of 152 neonates, infants, children, and adults with Beckwith-Wiedemann syndrome (age range, 1 day to 30 years old; median age, 1 year 3 months old) were retrospectively reviewed by three radiologists. Available pathologic material also was reviewed.

RESULTS

Thirty-eight (25%) of 152 patients with Beckwith-Wiedemann syndrome had 45 nonmalignant renal abnormalities, including medullary renal cysts (n = 19, 13%), caliceal diverticula (n = 2, 1%), hydronephrosis (n = 18, 12%), and nephrolithiasis (n = 6, 4%). Thirty-three (87%) of the 38 patients with nonmalignant renal disease were asymptomatic. Clinical manifestations of the remaining five patients included urinary tract infections (n = 4) and flank pain due to obstructive stone disease (n = 1). Nonmalignant renal disease was mistaken for Wilms' tumor in two patients, resulting in unnecessary nephrectomies. Seven children (18%) had Wilms' tumor and nonmalignant renal disease.

CONCLUSION

Nonmalignant renal abnormalities occur in approximately 25% of patients with Beckwith-Wiedemann syndrome but are generally asymptomatic. Nonmalignant renal abnormalities should be considered in the differential diagnosis of a mass revealed during screening sonography of a patient with Beckwith-Wiedemann syndrome to avoid unnecessary surgery.

The pediatric knee

MR imaging has become an indispensable tool in the evaluation of knee disorders. It is now widely relied on by clinicians, especially orthopedic surgeons, for guiding arthroscopic procedures and for staging tumor prior to resection. MR imaging has proved so successful that it has largely replaced arthrography in the evaluation of knee problems.

Chest radiography as a predictor of outcome in posttransplantation lymphoproliferative disorder in lung allograft recipients

OBJECTIVE

The radiologic findings of posttransplantation lymphoproliferative disorder in lung transplant recipients have received little attention compared with the findings for recipients of other solid organ transplants. We describe the intrathoracic findings and explore whether the radiographic presentation can predict outcome.

MATERIALS AND METHODS

Twenty-six patients (mean age, 32 years; range, 2-63 years; 18 female, eight male) with histologically proven lymphoproliferative disorder were identified from 518 lung transplantation patients, a 5.0% frequency. Chest radiographs, obtained within 1 week of diagnosis, were compared with baseline posttransplantation radiographs for all 26 patients and with chest CT scans for 20 patients.

RESULTS

The interval between transplantation and diagnosis ranged from 6 weeks to 7 years (mean, 16 months; median, 6 months). The thorax was involved in 18 (69%) of 26 patients. A new chest radiographic abnormality was present in all 18 patients and provided the first indication of disease in 14 (78%) of 18 patients. The most common finding was a solitary pulmonary nodule, seen in nine (50%) of 18 patients. Other findings included multiple nodules, multifocal alveolar infiltrates, and hilar and mediastinal adenopathy. CT scans detected additional nodules and lymph nodes but did not show occult disease in any case that appeared normal on radiography. Eight (89%) of nine patients with solitary pulmonary nodules at presentation were alive 1 year after diagnosis, compared with six (35%) of 17 patients with other presentations (p < .01).

CONCLUSION

Thoracic manifestations are present in most lung transplant recipients with lymphoproliferative disorder. Patients with solitary nodules have a better outcome in the first year after diagnosis than do patients with other presentations.

Cognitive screening examinations for silent cerebral infarcts in sickle cell disease

OBJECTIVE

In children with sickle cell disease (SCD), silent cerebral infarcts are the most frequent cause of neurologic injury. We determined the sensitivity and specificity of selective neurocognitive measures when separating children with silent cerebral infarcts and SCD from sibling controls. Additionally, we tested the validity of the same cognitive measures to identify patients with overt strokes.

METHODS

We examined performance on a neuropsychologic battery containing measures of attention/executive, spatial, language, memory, and motor functioning for seven children with SCD and silent cerebral infarct, 21 children with SCD and overt stroke, and 17 normal siblings. Diagnosis of cerebral infarct was based on results of MRI.

RESULTS

Measures from the attention and executive domains were the most useful for identifying children with silent cerebral infarct. The Test of Variables of Attention was the most robust measure and yielded a sensitivity rate of 86% and a specificity rate of 81%. This measure also showed a sensitivity rate of 95% in identifying overt stroke.

CONCLUSIONS

Brief cognitive screening measures, if properly constructed, may be an effective means of identifying children with silent cerebral infarct. Future prospective studies should be pursued to assess the utility of cognitive screening for silent cerebral infarcts in SCD.

Cystic fibrosis: CT findings of colonic disease

PURPOSE

To determine the computed tomographic (CT) findings that are indicative of bowel disease in patients with cystic fibrosis.

MATERIALS AND METHODS

CT scans in patients with cystic fibrosis were retrospectively reviewed for evidence of colonic abnormalities, including wall thickening, mural striation, fatty proliferation of the mesentery, and soft-tissue infiltration of pericolonic fat.

RESULTS

Ten patients with colonic abnormalities on CT scans (case patients) and 16 patients with normal CT results (cohort patients) were identified. Colonic abnormalities in case patients included wall thickening (mean thickness, 6.4 mm) and mesenteric infiltration in all, increased pericolonic fat in six, and mural striation in five. The right colon was involved in all case patients; contiguous extension involved the transverse colon in five, the descending colon in two, and all segments in one. Wall thickness in cohort patients was less than 2 mm. Eight case patients had abdominal pain; one had bloody diarrhea. Histopathologic examination results included nonspecific mucosal inflammation in four case patients, wall edema in one, and no abnormality in one. No patient had identifiable infectious colitis, colonic stricture, bowel obstruction, fibrosis, or Crohn disease. Mean dose of pancreatic enzyme replacement was similar in both groups.

CONCLUSION

Proximal colonic wall thickening without stricture, pericolonic fat proliferation, and mesenteric infiltration are CT findings of colonic disease associated with cystic fibrosis.

Nephromegaly in infancy and early childhood: a risk factor for Wilms tumor in Beckwith-Wiedemann syndrome

OBJECTIVE

Beckwith-Wiedemann Syndrome (BWS) is an overgrowth syndrome associated with macrosomia, omphalocele, macroglossia, visceromegaly and Wilms tumor (WT). We conducted a case-control study in children with BWS to examine whether nephromegaly increases the risk of WT.

METHODS

The BWS Registry was used to identify control and case patients. Control patients were defined as children with BWS who were older than 6 years and had no imaging evidence of renal disease or previous WT and for whom complete records were available; 31 patients met these criteria. Case patients were defined as children with BWS who had WT and screening renal imaging before the diagnosis of WT; 12 of these patients had serial screening images before diagnosis of WT and comprised the study population. Only renal images obtained before the diagnosis of WT was made were used to assess renal length.

RESULTS

All 12 patients with WT had nephromegaly (> or =95th percentile of age adjusted renal length) on serial screening studies. Only four of 31 control patients (specificity = 86%) had nephromegaly resulting in an odds ratio of 72 (95% confidence interval = 13-391) for the risk of WT with nephromegaly.

CONCLUSIONS

In patients with BWS, persistent nephromegaly is a strong risk factor for the development of WT. If screening for WT is done in this population, infants with nephromegaly should be considered those at greatest risk for WT, and screening may be best targeted at this group.

Sickle cell disease: imaging of cerebrovascular complications

This case is reported because of the unusual blood findings, no duplicate of which I have ever seen described. Whether the blood picture represents merely a freakish poikilocytosis or is dependent on some peculiar physical or chemical condition of the blood, or is characteristic of some particular disease, I cannot at present answer. I report some details that may seem non-essential, thinking that if a similar blood condition is found in some other case a comparison of clinical conditions may help in solving the problem.

Pelvic tumors in childhood

Pelvic neoplasms can arise from the genitourinary tract, gonads, or soft tissues. When a pelvic mass is detected on physical examination or a conventional radiographic study imaging evaluation is performed to characterize the lesion further and determine its site of origin and extent. Ultrasonography is used initially for the evaluation of most suspected lower genitourinary and testicular masses, because it does not use ionizing radiation. If the lesion is malignant, CT scan or MR imaging are warranted to detect the extent of pelvic invasion prior to surgery, chemotherapy, or radiation therapy. CT scan and MR imaging can also be helpful when sonography is suboptimal because of abundant bowel gas, a problem often encountered in evaluating the presacral space. CT scan and MR imaging are not degraded by bowel gas, and hence are most useful for evaluating a presacral mass When a presacral mass is suspected to be malignant, MR imaging is superior to CT scan to detect intraspinal invasion and soft tissue infiltration.

Soft-copy versus hard-copy cranial sonography: intraobserver agreement and workstation efficiency

OBJECTIVE

The objective of the study was to determine the intraobserver agreement, confidence level, and efficiency in interpretation of soft-copy (workstation) versus hard-copy (laser-printed film) sonograms of the cranium.

MATERIALS AND METHODS

Cranial sonograms of 100 premature infants were randomly reviewed twice on both soft-copy and hard-copy images by three observers and were graded for hemorrhage using a five-level scale. The kappa statistic was calculated to measure intraobserver agreement. Differences in agreement were tested for statistical significance with a test for marginal homogeneity. Observers rated their confidence in interpretation using a six-point ordinal scale. Total viewing time was recorded, and videotaped sessions were analyzed for image handling time (opening each case, closing each case, and selecting the next case) and interpretation time.

RESULTS

For soft copy versus hard copy, the mean kappa value was .73; for hard-copy 1 versus hard-copy 2, .71; and for soft-copy 1 versus soft-copy 2, .65. None of these differences was statistically significant (p > .05). The mean confidence score was the same for soft copy (5.3) and hard copy (5.3). On average, the observers needed 24 min longer to review 100 studies on soft copy than on hard copy. Opening and closing times for soft copy were significantly faster than for hard copy (p = .0001); however, case selection for soft copy, which was not needed for hard copy, took 4.69-9.09 sec per case. Extrapolated to 100 cases, case selection accounted for 8-15 min of viewing time.

CONCLUSION

Radiologist agreement and confidence in the interpretation of cranial sonograms for hemorrhage was the same for soft copy and hard copy. However, viewing times were longer for soft copy. Elimination of inefficiency in case selection could improve image-handling time.

From the RSNA refresher courses. Challenges of pediatric spiral CT

Spiral technology has expanded the usefulness of computed tomography (CT) in the evaluation of pediatric diseases. Even though spiral CT requires shorter total scanning times, image degradation by patient motion is still a problem in very young patients, and oral and intravenous sedatives are administered to minimize this problem. Optimal parenchymal enhancement depends on the amount and injection rate of contrast material and the timing of the onset of scanning. All these are more variable in studies of children than in adults, with the latter being the most complicated. Spiral CT of the pediatric chest is most useful for evaluating anastomotic dehiscence and stenosis in lung transplant recipients, pulmonary nodules in children with malignant disease likely to disseminate to the lung, and great vessel anomalies; for staging pulmonary tumors; and for dynamic imaging to identify various diseases that cause pulmonary dysfunction. Important applications of spiral CT of the pediatric abdomen and pelvis include evaluating the liver for acquired vascular abnormalities and vascular tumors, staging and preoperative assessment of renal tumors, and evaluating inflammatory pelvic lesions.

The acute scrotum

In the pediatric age group, color Doppler sonography appears to be as accurate as scintigraphy in evaluating causes of acute scrotal pain, provided that sensitivity for detecting low-velocity flow is adequate. Sonography has the advantage of providing anatomic information and it lacks radiation. Scintigraphy remains a reliable method of evaluating acute scrotal pain and should be used when color Doppler sensitivity for low-velocity, low-volume testicular blood flow is inadequate leading to doubt about the sonographic diagnosis. It is also advocated when examiner expertise with color Doppler sonography is limited. Regardless of which imaging study one prefers, it needs to be recognized that imaging of any type is not warranted in patients with a high clinical suspicion of torsion, because it delays immediate surgical treatment needed to prevent permanent damage.