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P J Pickhardt

Publications and source records attributed to P J Pickhardt.

At least 19 recordsLinked to original sources
PubMed2005

Virtual colonoscopy for primary screening. The future is now.

Virtual colonoscopy (VC) is a minimally invasive tool that utilizes modern CT technology for colorectal evaluation. Since its inception in 1994, VC has continued to rapidly evolve and improve as a diagnostic screening tool. Early success using primary two-dimensional (2D) detection in polyp-rich cohorts was followed by disappointing results in low prevalence populations. Subsequent introduction of the three-dimensional (3D) endoluminal display for primary polyp detection and oral contrast tagging has transformed VC into an effective primary screening tool. This state-of-the-art VC technique has already proven to be a viable enterprise when combined with existing optical colonoscopy practice. More widespread implementation of VC screening faces multiple challenges, but these are all greatly overshadowed by the immediate need for increased participation in effective colorectal screening. Given its relatively noninvasive nature and the wide availability of CT, VC holds significant potential for addressing a very important yet preventable public health concern. This review will cover current VC technique, compare the existing multi-center VC trials, discuss issues related to primary VC screening, and briefly update the progress of our VC screening program.

Algorithms↗
PubMed2001

Collecting duct carcinoma of the kidney: are imaging findings suggestive of the diagnosis?

OBJECTIVE: Collecting duct carcinoma derives from the renal medulla and has an infiltrative growth pattern at pathologic examination. The purpose of our study was to characterize the imaging features of this aggressive malignancy and determine whether the diagnosis can be reliably suggested from imaging findings. MATERIALS AND METHODS: Radiologic studies from 17 patients with pathologically proven collecting duct carcinoma were analyzed by two reviewers. RESULTS: The tumors varied in size from 1.5 to 19 cm (mean, 7.7 cm). Medullary involvement was present on CT in 16 (94%) of 17 cases, but cortical involvement or an exophytic component was also present in 15 cases (88%) and 10 cases (59%), respectively. The reniform contour of the kidney was preserved in seven cases (41%) and correlated with a smaller tumor size (p<0.01). Tumors showed an infiltrative appearance on CT in 11 cases (65%), but an expansile component was also present in eight of these cases. A cystic component was present on CT in six (35%) of 17 cases. On sonography, the solid tumor component was hyperechoic to normal renal parenchyma in six of seven cases and isoechoic in the other. On MR imaging, all tumors (4/4) were hypointense on T2-weighted imaging. On urography, all lesions (5/5) distorted the intrarenal collecting system. On angiography, all tumors (3/3) were hypovascular. CONCLUSION: Medullary involvement and an infiltrative appearance are common findings on cross-sectional imaging and may suggest the diagnosis of collecting duct carcinoma. In large tumors, however, these features are frequently overshadowed by an exophytic or expansile component that cannot be distinguished from the more common cortical renal cell carcinoma.

Carcinoma, Renal Cell↗
PubMed2000

Posttransplantation lymphoproliferative disorder in children: clinical, histopathologic, and imaging features.

Posttransplantation lymphoproliferative disorder (PTLD) is a condition in patients who receive transplants in which chronic immunosuppression leads to an unregulated expansion of lymphoid cells; the condition ranges from hyperplasia to malignant lymphoid proliferation. Risk factors affecting the incidence of PTLD include allograft type, Epstein-Barr virus infection, and immunosuppression. In this article, we review the clinical, histopathologic, and imaging features of PTLD in children. Because PTLD can affect nearly any organ system, a wide variety of clinical manifestations is possible. The heterogeneous nature of the disease is also reflected on imaging studies. The goals of imaging in patients with PTLD are to detect disease, guide biopsy, and direct appropriate follow-up imaging rather than to establish a specific diagnosis. Because the clinical and imaging manifestations of PTLD are nonspecific and are not reliably predictive of histopathologic subtype, tissue biopsy is necessary for final diagnosis.

Biopsy↗
PubMed1999

Desmoplastic small round cell tumor of the abdomen: radiologic-histopathologic correlation.

PURPOSE: To characterize the imaging features of desmoplastic small round cell tumor of the abdomen and correlate them with the histopathologic findings. MATERIALS AND METHODS: Eleven of 14 patients with desmoplastic small round cell tumor had primary abdominal involvement. In nine of these patients (mean age, 20 years), results of imaging studies (computed tomography in nine patients, ultrasonography [US] in three) and histopathologic specimens were retrospectively analyzed. RESULTS: The hallmark imaging feature was lobulated peritoneal masses (mean number, 4.4; range, 1-17) with a mean diameter of 5.0 cm (range, 2-12 cm). Omental and paravesical tumors were each present in six patients. Retroperitoneal masses were present in three patients. The tumors were well defined and hypoechoic at US. Heterogeneity due to tumor hemorrhage or necrosis was seen in seven patients. Ascites was present in five patients. Parenchymal and/or serosal hepatic metastases, punctate calcifications, nodular peritoneal thickening, lymphadenopathy, hydronephrosis, and bowel obstruction were less common associated findings. CONCLUSION: Bulky peritoneal soft-tissue masses without an apparent organ-based primary site are characteristic of intraabdominal desmoplastic small round cell tumor. Although the findings are nonspecific, this diagnosis can be considered in adolescents and young adults with characteristic imaging findings.

Abdominal Neoplasms↗
PubMed1999

Posttransplantation lymphoproliferative disorder of the abdomen: CT evaluation in 51 patients.

PURPOSE: To study the appearance and distribution of posttransplantation lymphoproliferative disorder (PTLD) at abdominal computed tomography (CT). MATERIALS AND METHODS: The authors retrospectively analyzed pretreatment abdominal CT scans in 51 patients (mean age, 36 years) with PTLD after solid organ transplantation. All diagnoses were proved at either abdominal (n = 26) or extraabdominal (n = 25) pathologic examination. Presence or absence of abdominal involvement, appearance and distribution of disease, and association with abdominal symptoms were all analyzed. RESULTS: CT scans were abnormal in 36 of the 51 patients (71%). Fifteen patients (29%) had no CT, clinical, or pathologic evidence of abdominal involvement. Of the 36 patients with abdominal PTLD at CT, 22% had lymph node enlargement, 28% splenic involvement, and 81% extranodal or extrasplenic involvement. Extranodal abdominal sites included liver (53%), small bowel (25%), kidney (17%), mesentery (14%), adrenal gland (8%), abdominal wall (8%), colon (6%), stomach (3%), and gallbladder (3%). Frequency of abdominal involvement was greater for heart and liver transplant recipients (94%) than for lung and kidney transplant recipients (58%) (P < .01). Seventeen of 36 patients (47%) with abdominal PTLD had no evidence of extraabdominal disease. CONCLUSION: Extranodal involvement is more common than splenic or nodal involvement in patients with abdominal PTLD. The presence of such findings in a patient after transplantation strongly suggests the diagnosis of PTLD and warrants aggressive evaluation.

Adolescent↗
PubMed1999

The abdominal compartment syndrome: CT findings.

OBJECTIVE: The abdominal compartment syndrome is a potentially fatal condition resulting from pathologic elevation of intraabdominal pressure. We evaluated preoperative abdominal CT scans of four patients with proven abdominal compartment syndrome to identify signs of increased intraabdominal pressure. CONCLUSION: CT findings common to all four patients included tense infiltration of the retroperitoneum out of proportion to peritoneal disease, extrinsic compression of the inferior vena cava by retroperitoneal hemorrhage or exudate, and massive abdominal distention with an increased ratio of anteroposterior-to-transverse abdominal diameter (positive round belly sign; ratio > .80; p < .001). Direct renal compression or displacement, bowel wall thickening with enhancement, and bilateral inguinal herniation were each present in two of the four patients. Radiologists should be aware of this life-threatening syndrome. In the appropriate clinical setting, CT findings of increased intraabdominal pressure should be swiftly communicated to other physicians involved in treating the patient because the abdominal compartment syndrome requires emergent surgical decompression.

Abdomen↗
PubMed1998

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.

Adolescent↗
PubMed1998

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.

Adolescent↗
PubMed1998

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.

Adolescent↗