Jay P. Heiken

Computed body tomography with MRI correlation

Chapter 1. CT Principles and Techniques, Including CTA Chapter 2. MRI: Basic Principles and Techniques Chapter 3. Interventional CT Technique, Including RF Ablation and CT Fluoroscopy Chapter 4. Neck Chapter 5. Thorax: Techniques and Normal Anatomy Chapter 6. Mediastinum Chapter 7. Lung Chapter 8. Pleura, Chest Wall and Diaphragm Chapter 9. Heart and Pericardium Chapter 10. Normal Abdominal and Pelvic Anatomy Chapter 11. Gastrointestinal Tract Chapter 12. Liver Chapter 13. Biliary Tract Chapter 14. Spleen Chapter 15. Pancreas Chapter 16. Abdominal Wall and Peritoneal Cavity Chapter 17. Retroperitoneum Chapter 18. Kidney Chapter 19. Adrenals Chapter 20. Pelvis Chapter 21. Trauma Chapter 22. Non-traumatic Acute Abdomen Chapter 23. Musculoskeletal Chapter 24. Spine Chapter 25. Pediatrics

Contrast-induced nephropathy in patients with chronic kidney disease undergoing computed tomography: a double-blind comparison of iodixanol and iopamidol.

Background:Based on a single clinical trial, it has been suggested that the contrast agent iodixanol, which is isotonic to human plasma, may be less nephrotoxic than other nonionic contrast agents in renally impaired patients after intra-arterial injection. We compared the effects on renal function of iopamidol-370 injection (796 mOsm/kg) and iodixanol-320 (290 mOsm/kg) in patients with chronic kidney disease undergoing contrast-enhanced multidetector computed tomography (CE-MDCT) examinations using a multicenter, double-blind, randomized, parallel-group design. Methods:A total of 166 patients with stable moderate-to-severe chronic kidney disease (screening and baseline serum creatinine, SCr, ≥1.5 mg/dL and/or creatinine clearance, CrCl, ≤60 mL/min) who were undergoing CE-MDCT of the liver or peripheral arteries were randomized to receive equi-iodine IV doses (40 gI) of either iopamidol-370 (370 mgI/mL) or iodixanol-320 (320 mgI/mL) at 4 mL/s. SCr and CrCl were obtained at screening, baseline, and at 48–72 ± 6 hours after dose (mean, 57.4 hours). Contrast-induced nephropathy (CIN) was defined as an absolute increase ≥0.5 mg/dL (44.2 &mgr;mol/L) and/or a relative increase in SCr ≥25% from baseline. Results:A total of 153 patients were included in the final analysis (13 patients excluded because of lack of follow-up, hemodialysis to remove contrast, average daily CrCl variation >1% at screening). The 2 study groups were comparable with regard to age, gender distribution, the presence of diabetes, concomitant medications, hydration, and contrast dose. Mean predose SCr was 1.6 ± 0.4 mg/dL in both groups (P = 0.9). An absolute increase ≥0.5 mg/dL (44.2 &mgr;mol/L) in SCr was observed in none of the patients receiving iopamidol-370 and in 2.6% (2/76) of patients receiving iodixanol-320 (95% confidence interval −6.2, 1.0, P = 0.2). A relative increase ≥25% in SCr occurred in 4% (3/77) of patients receiving iopamidol-370 and in 4% (3/76) of the patients receiving iodixanol-320 (95% confidence interval −6.2, 6.1, P = 1.0). Conclusion:The rate of CIN was similarly low in risk patients after intravenous administration of iopamidol-370 or iodixanol-320 for CE-MDCT.

The PREDICT Study: A Randomized Double-Blind Comparison of Contrast-Induced Nephropathy After Low- or Isoosmolar Contrast Agent Exposure

OBJECTIVE The objective of the PREDICT (patients with renal impairment and diabetes undergoing computed tomography) study was to compare the incidence of contrast-induced nephropathy (CIN) after administration of low-osmolar (iopamidol 370, 796 mOsm/kg) or isoosmolar (iodixanol 320, 290 mOsm/kg) contrast medium in patients with diabetes and chronic kidney disease undergoing CT. SUBJECTS AND METHODS Two hundred sixty-three patients with moderate to severe chronic kidney disease (estimated glomerular filtration rate [GFR] = 20-59 mL/min/1.73 m(2)) and diabetes mellitus were randomized to receive at least 65 mL of iopamidol 370 or iodixanol 320 for a CT procedure. Serum creatinine levels were measured at baseline and 48-72 hours after contrast administration. CIN was defined as an increase in the serum creatinine level after contrast administration of >or= 25% from the baseline level. The incidence of CIN in the total study population and the incidence of CIN in patients at increased risk for CIN were compared using Fishers exact test. RESULTS Two hundred forty-eight patients were included in the CIN analysis: 125 receiving iopamidol 370 and 123 receiving iodixanol 320. Study population demographics were comparable, as was baseline renal function (estimated GFR = 47.6 mL/min/1.73 m(2) for the iopamidol 370 group vs 49.9 mL/min/1.73 m(2) for the iodixanol 320 group; p = 0.16). Increases in the serum creatinine value of >or= 25% occurred in seven patients (5.6%) receiving iopamidol 370 and in six patients (4.9%) receiving iodixanol 320 (95% CI, -4.8% to 6.3%; p = 1.0). The mean serum creatinine change from the baseline level was 0.04 mg/dL in both groups (analysis of covariance, p = 0.80). In patients with a baseline serum creatinine value of >or= 2.0 mg/dL, baseline estimated GFR of <or= 40 mL/min/1.73 m(2), or those receiving > 140 mL of contrast medium, the incidence of CIN was low and comparable between the two study groups (p = 1.0 in all instances). CONCLUSION The incidence of CIN in patients with diabetes and chronic kidney disease receiving IV contrast medium was not significantly different after CT using iopamidol 370 or iodixanol 320.

Computed tomography of renal lymphoma with ultrasound correlation.

The computed tomography (CT) and ultrasound findings in 18 patients (35 kidneys) with non-Hodgkin lymphoma involving the kidneys are presented. Renal involvement was bilateral in 13 patients. The most common presentation was that of multiple intraparenchymal nodules (15 kidneys). Other types of involvement included direct invasion from contiguous retroperitoneal lymph node masses (nine kidneys), solitary renal masses (five kidneys), and diffuse infiltration (two kidneys). On CT most of the lesions were of homogeneous tissue density. Ultrasonographically the renal masses were hypoechoic. We believe that CT is the procedure of choice for the detection and follow-up of renal lymphoma.

Comparison of helical computerized tomography and plain radiography for estimating urinary stone size.

PURPOSE We evaluated the accuracy of noncontrast spiral computerized tomography (CT) for determining urinary stone size compared with plain x-ray. MATERIALS AND METHODS We retrospectively analyzed noncontrast helical CT and plain x-ray of the kidneys, ureters and bladder images of 39 patients with urolithiasis who underwent each study from July 1997 to February 1999. Stone size on x-ray was measured in the craniocaudal and transverse dimensions by a single radiologist (I.C.B.). The size of the same stone was then determined on blinded noncontrast spiral CT images. Stones that were less than 3 mm. were excluded from study. On CT estimated craniocaudal dimension was based on collimation thickness, the reconstruction interval and the number of images on which the stone was visualized. RESULTS We evaluated 58 stones 3 mm. or larger in the greatest dimension on plain x-ray of the kidneys, ureters and bladder, and noncontrast spiral CT, including 15 in the distal ureter, 7 in the mid or proximal ureter and 36 in the kidneys. Stone size was 3 to 18 mm. in the greatest dimension. Mean transverse dimension of the stone plus or minus standard deviation on noncontrast spiral CT was 5.1 +/- 1.08 versus 4.9 +/- 1.08 mm. on plain x-ray of the kidneys, ureters and bladder (paired t test; p = 0.335). The mean craniocaudal dimension on noncontrast spiral CT was 7.5 +/- 1.98 versus 6.7 +/- 1.98 mm. on plain x-ray paired t test (p = 0.005). CONCLUSIONS Noncontrast spiral CT enables a similar measurement of stone size along the transverse dimension as plain x-ray of the kidneys, ureters and bladder. In individuals noncontrast spiral CT does not accurately measure the craniocaudal dimension of stones compared with plain x-ray when standard acquisition and reconstruction techniques are used. In this regard it has a tendency to overestimate stone size by an average of 0.8 mm.

Vascular Malformation and Hemangiomatosis Syndromes: Spectrum of Imaging Manifestations

OBJECTIVE The purpose of this review is to describe the role of imaging and associated findings in the diagnosis of blue rubber bleb nevus syndrome, Proteus syndrome, Klippel-Trénaunay syndrome, and Kasabach-Merritt syndrome. CONCLUSION Blue rubber bleb nevus, Proteus, Klippel-Trénaunay, and Kasabach-Merritt syndromes are a diverse group of vascular malformation and hemangiomatosis syndromes. Both cutaneous and visceral vascular lesions are associated with these disorders. Accurate diagnosis of these syndromes is important because they can be associated with serious complications, including life-threatening hemorrhage.

Hepatobiliary agents and their role in LI-RADS

The Liver Imaging Reporting and Data System (LI-RADS) was introduced with the goal of standardizing the diagnosis of hepatocellular carcinoma. The 2014 version of LI-RADS incorporates the use of hepatobiliary contrast agents (HBAs) into the diagnostic algorithm, including gadoxetate disodium and gadobenate dimeglumine. Three new ancillary features are introduced: hepatobiliary phase (HBP) hypointensity and HBP hypointense rim favor malignancy, while HBP isointensity favors benignity. HBP hyperintensity favors neither malignancy nor benignity. In this review, we describe how to use these new features as well as numerous pitfalls associated with the use ofHBAs, including hemangiomas, cholangiocarcinomas, and focal confluent fibrosis. Importantly, findings on the HBP are not included as major criteria and therefore the criteria for the diagnosis of LI-RADS 5 observations remain unchanged, and so congruence with the Organ Procurement Transplant Network system remains intact. Additionally, we review how the major features in LI-RADS, arterial phase hyperenhancement, threshold growth, and washout and capsule appearance, may be affected with HBAs. Notably with HBAs, hypointensity on the delayed phase, termed the transitional phase, does not qualify as washout appearance due to the possibility of early parenchymal enhancement. It is hoped that the incorporation of HBAs into LI-RADS will help create consistency when interpreting HBA enhanced MRIs.

Distinguishing benign from malignant liver tumours

Abstract Liver masses are very common and most are benign. It is therefore important to avoid unnecessary interventions for benign lesions, while at the same time ensuring accurate diagnosis of hepatic malignancies. Many cancer patients, like the general population, have incidental benign liver lesions. In planning treatment for cancer patients, it is critical to avoid inappropriate treatment decisions based on misdiagnosis of a benign lesion as a metastasis or primary liver malignancy. This article describes the salient imaging features of the common benign liver masses and outlines a general approach to distinguishing between benign and malignant hepatic lesions.

Comparison of computed tomography and conventional cystography for detection of traumatic bladder rupture.

Computed tomography (CT) is the method of choice for evaluating patients with blunt abdominal and/or pelvic trauma. However, the sensitivity of CT for detecting bladder ruptures has been questioned. We reviewed both the conventional cystograms and the CT examinations of 25 patients who had both studies as the initial evaluation of blunt abdominal and pelvic trauma in the last 5 years. Five of these 25 patients had bladder ruptures, three extraperitoneal and two intraperitoneal. All five injuries were detected by both CT and conventional cystography. In one patient the conventional cystogram was falsely positive. In this case the correct diagnosis was made by CT, and a repeat cystogram confirmed that no bladder injury was present. Our results indicate that CT, if properly performed, is as sensitive for detection of bladder injuries as conventional cystography.

Spiral computed tomographic colonography: Determination of the central axis and digital unraveling of the colon

RATIONALE AND OBJECTIVES The authors developed and tested automated and semiautomated bowel-lumen tracking and colon-unraveling techniques for determining the central axis of the bowel. METHODS A computer-simulated gastrointestinal tract phantom was used to test the accuracy of an automated algorithm for central axis determination and bowel unraveling. Variations in cross-sectional features between straight and unraveled formats were compared in a canine bowel segment in vitro and a human colon in vivo by using spiral computed tomography. Three readers each performed three semiautomated evaluations. RESULTS Accuracy of the automated algorithm was confirmed by the high degree of correlation in the cross-sectional feature measurements (length error, < 1%). For the canine colon segment, accuracy of the semiautomated algorithm was confirmed by comparison with the automated tracing. For the human colon, readings were reproducible with 3.3% (+/- 1.9 standard deviation) mean variation in length. CONCLUSION An automated algorithm for central axis deterioration and unraveling the colon has been validated in a gastrointestinal tract phantom. A semiautomated algorithm has been shown to be reproducible and time-efficient.