Perry J Pickhardt

University of Wisconsin–Madison, Madison, Wisconsin, United States

Are you Perry J Pickhardt?

Claim your profile

Publications (42)177.89 Total impact

  • [Show abstract] [Hide abstract]
    ABSTRACT: Many solid tumors contain an overabundance of phospholipid ethers relative to normal cells. Capitalizing on this difference, we created cancer-targeted alkylphosphocholine (APC) analogs through structure-activity analyses. Depending on the iodine isotope used, radioiodinated APC analog CLR1404 was used as either a positron emission tomography (PET) imaging ((124)I) or molecular radiotherapeutic ((131)I) agent. CLR1404 analogs displayed prolonged tumor-selective retention in 55 in vivo rodent and human cancer and cancer stem cell models. (131)I-CLR1404 also displayed efficacy (tumor growth suppression and survival extension) in a wide range of human tumor xenograft models. Human PET/CT (computed tomography) and SPECT (single-photon emission computed tomography)/CT imaging in advanced-cancer patients with (124)I-CLR1404 or (131)I-CLR1404, respectively, demonstrated selective uptake and prolonged retention in both primary and metastatic malignant tumors. Combined application of these chemically identical APC-based radioisosteres will enable personalized dual modality cancer therapy of using molecular (124)I-CLR1404 tumor imaging for planning (131)I-CLR1404 therapy.
    Science translational medicine 06/2014; 6(240):240ra75. · 10.76 Impact Factor
  • [Show abstract] [Hide abstract]
    ABSTRACT: For patients undergoing screening computed tomography colonography (CTC), an opportunity exists for bone mineral density (BMD) screening without additional radiation exposure using quantitative computed tomography (QCT). This study investigated the use of dual-energy X-ray absorptiometry (DXA)-equivalent QCT Computed Tomography X-Ray Absorptiometry (CTXA) analysis at the hip obtained using CTC examinations using a retrospective asynchronous calibration of patient scans. A cohort of 33 women, age 61.3 (10.6) yr (mean [standard deviation]), had routine CTC using various GE LightSpeed CT scanner models followed after 0-9 mo by a DXA hip BMD examination using a GE Lunar Prodigy machine. Areal bone mineral density (aBMD) and T-scores of the proximal femur were measured from either prone or supine CTC examinations using Mindways QCT Pro software following standard workflow except that the CT scanners were asynchronously calibrated by phantoms scanned retrospectively of the CTC examination without the subject present. CTXA and DXA aBMD were highly correlated (R(2) = 0.907) with a linear relationship of DXA_BMD = 1.297*CTXA_BMD + 0.048. The standard error of estimate (SEE) on the linear fit was 0.053 g/cm(2). CTXA and DXA T-scores showed a linear relationship of DXA_T-score = 1.034*CTXA_T-score + 0.3 and an SEE of 0.379 T-scores. CTXA and DXA aBMD and T-score measurements showed good correlation despite asynchronous scan acquisition and retrospective QCT calibration. The SEE of 0.053 g/cm(2) is on par with the literature comparing Hologic and Lunar DXA devices. The observed relationship between CTXA and Lunar DXA aBMD matches predictions from published cross-calibrations relating CTXA to DXA aBMD measurement. Thus, opportunistic use of CTXA T-scores obtained at the time of CTC could enhance osteoporosis screening.
    Journal of clinical densitometry : the official journal of the International Society for Clinical Densitometry. 05/2014;
  • Source
    Perry J Pickhardt
    [Show abstract] [Hide abstract]
    ABSTRACT: Existing and emerging colorectal screening tests can be assessed in terms of the key categories of diagnostic performance, procedural risks, patient acceptability, and cost-effectiveness. To push a new screening test to acceptance, it need not outperform existing strategies in all of these criteria. Rather, a relative advantage in one criterion combined with acceptable performance in the others may be considered adequate. For computed tomographic colonography (CTC), a strong case can be made that this test meets or exceeds optical colonoscopy, the current screening standard, in all of these categories. Published data, including our own experience with CTC screening, will be reviewed to support this claim. Reasons why CTC has not yet achieved its full potential as a valuable screening test for colorectal cancer prevention will also be considered.
    Expert review of gastroenterology & hepatology 02/2014;
  • Article: Response.
    Perry J Pickhardt, George Carberry
    Radiology 02/2014; 270(2):632. · 6.34 Impact Factor
  • Journal of Clinical Densitometry 01/2014; 17(3):408–409. · 1.71 Impact Factor
  • [Show abstract] [Hide abstract]
    ABSTRACT: For patients undergoing screening computed tomography colonography (CTC), an opportunity exists for bone mineral density (BMD) screening without additional radiation exposure using quantitative computed tomography (QCT). This study investigated the use of dual-energy X-ray absorptiometry (DXA)–equivalent QCT Computed Tomography X-Ray Absorptiometry (CTXA) analysis at the hip obtained using CTC examinations using a retrospective asynchronous calibration of patient scans. A cohort of 33 women, age 61.3 (10.6) yr (mean [standard deviation]), had routine CTC using various GE LightSpeed CT scanner models followed after 0–9 mo by a DXA hip BMD examination using a GE Lunar Prodigy machine. Areal bone mineral density (aBMD) and T-scores of the proximal femur were measured from either prone or supine CTC examinations using Mindways QCT Pro software following standard workflow except that the CT scanners were asynchronously calibrated by phantoms scanned retrospectively of the CTC examination without the subject present. CTXA and DXA aBMD were highly correlated (R2 = 0.907) with a linear relationship of DXA_BMD = 1.297*CTXA_BMD + 0.048. The standard error of estimate (SEE) on the linear fit was 0.053 g/cm2. CTXA and DXA T-scores showed a linear relationship of DXA_T-score = 1.034*CTXA_T-score + 0.3 and an SEE of 0.379 T-scores. CTXA and DXA aBMD and T-score measurements showed good correlation despite asynchronous scan acquisition and retrospective QCT calibration. The SEE of 0.053 g/cm2 is on par with the literature comparing Hologic and Lunar DXA devices. The observed relationship between CTXA and Lunar DXA aBMD matches predictions from published cross-calibrations relating CTXA to DXA aBMD measurement. Thus, opportunistic use of CTXA T-scores obtained at the time of CTC could enhance osteoporosis screening.
    Journal of Clinical Densitometry 01/2014; · 1.71 Impact Factor
  • Journal of Clinical Densitometry 01/2014; 17(3):408. · 1.71 Impact Factor
  • Nicola Flor, Francesco Sardanelli, Perry J Pickhardt
    Scandinavian Journal of Gastroenterology 11/2013; · 2.33 Impact Factor
  • [Show abstract] [Hide abstract]
    ABSTRACT: OBJECTIVE: We propose a diverticular disease severity score (DDSS) based on CT colonography (CTC) findings. METHODS: Seventy-nine patients (62 ± 14.5 years) underwent CTC after recovering from an episode of acute diverticulitis. Two independent readers classified each case using a four-point scale (DDSS), based on maximum sigmoid colon wall thickness (MSCWT) and minimum lumen diameter at CTC: 1 = MSCWT <3 mm, lumen diameter ≥15 mm; 2 = MSCWT 3-8 mm, lumen diameter ≥5 mm; 3 = MSCWT ≥8 mm, lumen diameter ≥5 mm; 4 = MSCWT ≥8 mm, lumen diameter <5 mm. Intra- and interobserver reproducibility was evaluated. Of 79 patients, 32 (40 %) underwent surgery after CTC; MSCWT was directly measured on the pathological specimen. RESULTS: Intra- and interobserver reproducibility of DDSS were almost perfect (k = 0.90-0.84). DDSS significantly correlated with the probability of surgery (P = 0.001). After surgery, histopathology revealed acute/chronic diverticular inflammation only in 29 cases, and superimposed sigmoid cancer (n = 2) or Crohn's disease (n = 1) in 3 patients with a DDSS of 4. MSCWT at histopathology correlated with DDSS (P = 0.008). CONCLUSION: DDSS is highly reproducible and correlates with pathological MSCWT. Nearly 1 in 3 patients with a DDSS of 4 had significant superimposed histopathology. CTC with DDSS can provide colorectal surgeons with valuable information. KEY POINTS: • A diverticular disease severity score (DDSS) based on CT colonography is proposed. • This DDSS is based on sigmoid colon wall thickness and lumen diameter. • High scores may be associated with relevant coexisting lesions. • A CTC-based DDSS may influence therapeutic decision-making.
    European Radiology 05/2013; · 4.34 Impact Factor
  • Article: Preface.
    Perry J Pickhardt
    Radiologic Clinics of North America 01/2013; 51(1):xi. · 1.95 Impact Factor
  • [Show abstract] [Hide abstract]
    ABSTRACT: The effect of CT colonography (CTC) screening on colonoscopy is unknown. The objective of this study is to determine the effect of a CTC screening program on the number of screening, therapeutic and total colonoscopies performed. We compared the quarterly mean numbers of colonoscopic examinations performed for 50-79 year olds undergoing colorectal cancer screening in 2003, before initiation of a CTC program, to 2011, seven years after the CTC program began at our academic tertiary care facility. The CTC program began in 2004 with a peak number of 387 CTC examinations performed in the 3rd quarter of 2005 and 275 examinations in the final quarter of 2011. Screening colonoscopies increased from 555 mean/quarter in 2003 to 1460 in 2011 (P < 0.001). The mean/quarter number of total colonoscopies performed increased from 1104 in 2003 to 2382 in 2011 (P < 0.001). The number of overall colon cancer screening examinations (Colonoscopy + CTC) increased from 555/quarter in 2003 to 1736 in 2011 (P < 0.001). Since the initiation of CTC screening at our institution, the overall number of total colorectal cancer screening examinations (CTC + colonoscopy) has greatly increased. The initiation of a CTC screening program did not lead to a reduction in the number of colonoscopic examinations performed. Conversely, a significant increase in the number of screening and total colonoscopies completed was observed.
    Journal of gastrointestinal and liver diseases: JGLD 12/2012; 21(4):391-5. · 1.86 Impact Factor
  • H Zhu, M Barish, P Pickhardt, J Liang
    [Show abstract] [Hide abstract]
    ABSTRACT: Human colon has complex structures mostly because of the haustral folds. The folds are thin flat protrusions on the colon wall, which complicate the shape analysis for computer-aided detection (CAD) of colonic polyps. Fold segmentation may help reduce the structural complexity, and the folds can serve as anatomic reference for computed tomographic colonography (CTC). Therefore, in this study, based on a model of the haustral fold boundaries, we developed a level-set approach to automatically segment the fold surfaces. To evaluate the developed fold segmentation algorithm, we first established the ground truth of haustral fold boundaries by experts drawing on 15 patient CTC datasets without severe under/over colon distention from two medical centers. The segmentation algorithm successfully detected 92.7% of the folds in the ground truth. In addition to the sensitivity measure, we further developed a merit of segmented area ratio (SAR), i.e., the ratio between the area of the intersection and union of the expert-drawn folds and the area of the automatically-segmented folds, to measure the segmentation accuracy. The segmentation algorithm reached an average value of SAR=86.2%, showing a good match with the ground truth on the fold surfaces. We believe the automatically-segmented fold surfaces have the potential to benefit many post-procedures in CTC, e.g., CAD, taenia coli extraction, supine-prone registration, etc.
    IEEE transactions on bio-medical engineering 10/2012; · 2.15 Impact Factor
  • Perry J Pickhardt
    [Show abstract] [Hide abstract]
    ABSTRACT: PURPOSE OF REVIEW: Computed tomography colonography (CTC) continues to mature and evolve as a noninvasive imaging test of the large intestine. The aim of this review is to provide an update on the recent and emerging data that further supports the clinical effectiveness of CTC. RECENT FINDINGS: The diagnostic performance of CTC for detecting colorectal polyps and masses is well established, but its precise clinical role is yet to be determined. Recent data on test performance, patient acceptance, and study technique may help to clarify the role of CTC and accelerate its clinical implementation. SUMMARY: Recent advances and refinements in CTC should help to clarify and expand its clinical role, both as a screening and diagnostic test. High patient acceptance for CTC could lead to increased adherence rates. Ultimately, the complementary nature of CTC and optical colonoscopy should result in improved patient care.
    Current opinion in gastroenterology 10/2012; · 4.33 Impact Factor
  • Perry J Pickhardt
    [Show abstract] [Hide abstract]
    ABSTRACT: Misinterpretation at CT colonography (CTC) can result in either a colorectal lesion being missed (false-negative) or a false-positive diagnosis. This review will largely focus on potential missed lesions-and ways to avoid such misses. The general causes of false-negative interpretation at CTC can be broadly characterized and grouped into discrete categories related to suboptimal study technique, specific lesion characteristics, anatomic location, and imaging artifacts. Overlapping causes further increase the likelihood of missing a clinically relevant lesion. In the end, if the technical factors of bowel preparation, colonic distention, and robust CTC software are adequately addressed on a consistent basis, and the reader is aware of all the potential pitfalls at CTC, important lesions will seldom be missed.
    Abdominal Imaging 04/2012; · 1.91 Impact Factor
  • Perry J Pickhardt
    Nature Reviews Gastroenterology &#38 Hepatology 03/2012; 9(4):195-6. · 10.43 Impact Factor
  • Perry J Pickhardt
    [Show abstract] [Hide abstract]
    ABSTRACT: Colorectal cancer is a common yet preventable condition. Population screening attempts suffer from a lack of widespread participation with the currently available options. Computerized tomography colonography (CTC) represents a promising addition to the screening armamentarium. CTC is less invasive than optical colonoscopy but has been shown to be equivalent to colonoscopy for the detection of advanced neoplasia, which represents the primary target of screening and prevention. Although CTC has generally been preferred over colonoscopy by patients in most published studies, little hard evidence exists regarding the level of increase in screening participation related to CTC. The landmark trial under discussion adds key data in terms of participation rates for CTC screening relative to colonoscopy screening.
    Expert Review of Medical Devices 03/2012; 9(2):107-10. · 2.43 Impact Factor
  • [Show abstract] [Hide abstract]
    ABSTRACT: Human colon has complex structures mostly because of the haustral folds. Haustral folds are thin flat protrusions on the colon wall, which inherently attached on the colon wall. These structures may complicate the shape analysis for computer-aided detection of colonic polyps (CADpolyp); however, they can serve as solid reference during image interpretation in computed tomographic colonography (CTC). Therefore, in this study, based on a clear model of the haustral fold boundaries, we employ level set method to automatically segment the fold surfaces. We believe the segmented folds have the potential to significantly benefit various post-procedures in CTC, e.g., supine-prone registration, synchronized image interpretation, automatic polyp matching, CADpolyp, teniae coli extraction, etc. For the first time, with assistance from physician experts, we established the ground truth of haustral fold boundaries of 15 real patient data from two medical centers, based on which we evaluated our algorithm. The results demonstrated that about 92.7% of the folds are successfully detected. Furthermore, we explored the segmented area ratio (SAR), i.e., the ratio between the areas of the intersection and the union of the expert-drawn and the automatically-segmented folds, to measure the accuracy of the segmentation algorithm. The averaged result of SAR=86.2% shows a good match between the ground truth and our segmentation results.
    Proc SPIE 02/2012;
  • Perry J Pickhardt
    The Lancet Oncology 11/2011; 13(1):6-7. · 25.12 Impact Factor
  • Theodora A. Potretzke, Perry J. Pickhardt
    [Show abstract] [Hide abstract]
    ABSTRACT: Primary appendiceal neoplasms are relatively uncommon but are being detected with increasing frequency as an incidental finding at cross-sectional imaging. Clinical presentation of acute appendicitis related to tumoral obstruction represents the other major clinical manifestation of primary appendiceal neoplasms. In either case, radiologists should be vigilant for imaging findings suggestive of underlying tumor. Mucoceles resulting from mucinous cystic neoplasms account for the majority of appendiceal neoplasms detected at cross-sectional imaging, whether manifesting as a symptomatic lesion or as an incidental finding. Other primary tumor types that may be encountered include colonic-type adenocarcinoma, carcinoid tumors (classic, tubular, or goblet cell varieties), and non-Hodgkin’s lymphoma, among others. In addition, non-neoplastic processes may mimic a tumor at imaging. This chapter will review the salient clinical and imaging features of primary appendiceal neoplasms.
    09/2011: pages 199-219;
  • American Journal of Roentgenology 07/2011; 197(1):28-9. · 2.90 Impact Factor

Publication Stats

241 Citations
177.89 Total Impact Points

Institutions

  • 2004–2014
    • University of Wisconsin–Madison
      • • Department of Radiology
      • • Department of Medicine
      Madison, Wisconsin, United States
  • 2013
    • Azienda Ospedaliera San Paolo - Polo Universitario
      Milano, Lombardy, Italy
    • University of Milan
      • Department of Health Science - DISS
      Milano, Lombardy, Italy
  • 2011
    • University of California, San Francisco
      San Francisco, California, United States