Martina Morrin

Intravenous, contrast-enhanced MR colonography using air as endoluminal contrast agent: Impact on colorectal polyp detection.

PURPOSE To compare diagnostic accuracy and patient tolerance of MR colonography with intravenous contrast and luminal air (MRC) to conventional colonoscopy (CC). MATERIALS AND METHODS IRB approval and written informed consent were obtained. Forty-six patients, both screening and symptomatic, underwent MRC followed by CC. The MRC technique employed 3D T1W spoiled gradient echo sequences performed after the administration of gadopenetate dimeglumine, with parallel imaging. The diagnostic accuracy and tolerance of patients for MRC was compared to CC. RESULTS Twenty-four polyps were detected in eighteen patients with CC (5 polyps ≥ 10 mm, 4 polyps 6-9 mm, 15 polyps ≤ 5 mm). MRC was 66.7% (12/18) sensitive and 96.4% (27/28) specific for polyp detection on a per-patient basis. When analyzed by polyp size, sensitivity and specificity of MRC was 100% (5/5) and 100% (19/19), respectively, for lesions greater than 10mm, 100% (4/4) and 100% (20/20) for lesions 6-9 mm, and sensitivity of 20% (3/15) lesions less than 5mm. The sensitivity and specificity of MRC for detecting significant lesions (>6mm) was 100% (9/9) and 100% (15/15), respectively. Regarding tolerance of the exams, there were no significant differences between MRC and CC. Thirty-five percent (n=16) of patients preferred MRC as a future screening test compared to 33% (n=15) for CC. CONCLUSION MRC using air as an intraluminal contrast agent is a feasible and well-tolerated technique for detecting colonic polyps ≥ 6 mm in size. Further studies are warranted.

Parallel imaging enhanced MR colonography using a phantom model.

To compare various Array Spatial and Sensitivity Encoding Technique (ASSET)‐enhanced T2W SSFSE (single shot fast spin echo) and T1‐weighted (T1W) 3D SPGR (spoiled gradient recalled echo) sequences for polyp detection and image quality at MR colonography (MRC) in a phantom model. Limitations of MRC using standard 3D SPGR T1W imaging include the long breath‐hold required to cover the entire colon within one acquisition and the relatively low spatial resolution due to the long acquisition time. Parallel imaging using ASSET‐enhanced T2W SSFSE and 3D T1W SPGR imaging results in much shorter imaging times, which allows for increased spatial resolution.

Unusual Ischemic Complication of Bevacizumab Treatment for Metastatic Colorectal Carcinoma

Case Report A 36-year-old man presented with acute onset right upper quadrant pain, localized tenderness, and leucocytosis. One year earlier he was diagnosed with synchronous T4N2M1 cecal and rectal tumors. He had diffuse intraperitoneal metastasis at presentation. A diverting loop sigmoid colostomy was performed, followed by 12 cycles of leucovirin, fluorouracil, and oxaliplatin (FOLFOX). Bevacizumab (Avastin; Genentech, South San Francisco, CA) was commenced on the second cycle of FOLFOX and continued as maintenance treatment. Eleven months after commencing bevacizumab he presented acutely with severe right upper quadrant pain of 4-day duration. He was apyretic, with marked right upper quadrant tenderness. Blood investigations revealed leucocytosis (WBC 15 10/L) and mild nonspecific liver biochemistry abnormalities (bilirubin, 19 umol/L; alkaline phosphatase, 225 IU/L; gamma-glutamyl transferase, 149 IU/L). Oral and portal-venous phase contrast-enhanced computed tomography of the abdomen identified mural edema of the gallbladder with high attenuation luminal content, likely representing purulent material or hemorrhage. Multiple foci of nonenhancement of the gallbladder wall were suggestive of ischemia. There was no evidence of cholelithiasis or choledocholithiasis (Fig 1; arrows indicate foci of mural nonenhancement. There is preexisting right hydronephrosis secondary to metastatic colorectal malignancy, unchanged relative to prior imaging). Computed tomography of the thorax, abdomen, and pelvis performed 2 months previously and a further study before commencement of bevacizumab had demonstrated a normal gallbladder. Magnetic resonance cholangiopancreatography showed no evidence of cholelithiasis. A percutaneous cholecystostomy placed under ultrasound guidance drained black bilious fluid. Microscopy of the aspirated fluid demonstrated no organisms, pus cells, or bacterial growth following a 48-hour culture. The cholecystostomy was removed 6 weeks later and the patient suffered no further gallbladder complications.

Comparative diagnostic test accuracy of post-esophagectomy water-soluble computed tomography and fluoroscopic swallow studies: A meta-analysis

Aims: Both fluoroscopic water-soluble contrast swallow (FWSCS) and CT water-soluble contrast swallow (CTWSCS) are widely performed as a routine in the post-esophagectomy patient to assess for anastomotic leak. Several prospective studies have compared FWSCS and CTWSCS; however, no synthesis of the data exists. Materials and Methods: Systematic review and meta-analysis of diagnostic test accuracy studies comparing FWSCS and CTWSCS in the adult patient following esophagectomy for malignancy was performed in accordance with PRISMA guidelines. Results: Three diagnostic test accuracy studies met the inclusion criteria, directly comparing FWSCS and CTWSCS in 185 patients. FWSCS demonstrated high specificity (98%), but low sensitivity (64%). CTWSCS can be categorized as normal, mediastinal gas without contrast leak, or leakage of oral contrast. Visible leakage of oral contrast demonstrated high specificity (98%) but low sensitivity (56%). The presence of mediastinal gas increased sensitivity (84%), but reduced specificity (85%). The higher sensitivity of CTWSCS over FWSCS failed to reach significance (P = 0.125). Conclusion: CTWSCS shares the high specificity of FWSCS. Its higher sensitivity increases its utility as a rule-out test in the postoperative period. Additional factors that may influence decision-making are described.

Prevalence of Incidental Findings on Multidetector Computed Tomography in Potential Nephrectomy Donors: A Prospective Observational Study

OBJECTIVES Prospective renal donors are a select population of healthy individuals who have been thoroughly screened for significant comorbidities before they undergo multidetector computed tomography. Our aim was to determine the prevalence of incidental findings on preoperative multidetector computed tomography in a healthy cohort of potential living donors for kidney transplant. MATERIALS AND METHODS A prospective study was performed of prospective living kidney transplant donors at a national kidney transplant center. Study inclusion criteria were all potential kidney donors who underwent multidetector computed tomography during the living-donor assessment process over a 5-year period (January 2012 to 2017). RESULTS Our cohort included 375 potential living donors who had multidetector computed tomography; mean age was 44.33 years (range, 21-71.5 y). In total, there were 228 incidental findings identified in 158 individuals. Of the 375 potential donors, 193 (51%) proceeded to living donor nephrectomy. On multidetector computed tomography, 97 incidental findings were identified in the donor cohort versus 131 in the cohort that did not proceed to donation. Bosniak 1 renal cysts were the most common incidental finding (n = 46) followed by liver cysts < 1.5 cm (n = 42) and urinary tract calculi (n = 21). There was 1 incidentally detected pathologically proven malignancy. CONCLUSIONS A variety of incidentally detected lesions of moderate to high importance were detected in this healthy donor cohort. Individuals undergoing assessment with multidetector computed tomography for living donor nephrectomy should be counseled on medical, financial, and psychological implications of incidentally detected lesions during the kidney transplant evaluation process.

An unusual presentation of bilateral Hutch diverticula

Summary Hutch diverticula are rare congenital diverticula. The general consensus is that they occur secondary to a congenital failure of normal muscle development around the ureteral orifice where Waldeyer sheath anatomically covers the space between the intravesical ureter and muscular layer of the bladder. Our case highlights the radiological appearance of Hutch diverticula and the need for contrast-enhanced imaging to enable accurate evaluation and diagnosis. It illustrates how the presence of periureteric diverticula can contribute to ureteric obstruction and calculus formation; complicate the interpretation of renal tract imaging and the subsequent management of renal calculi.

Multiple Functional Parathyroid Cysts

A 43-year-old gentleman was diagnosed with primary hyperparathyroidism during treatment for kidney stones. Serum calcium measured 11.28 mg/dL (normal range, 8.8–10.4), with an elevated serum PTH of 155 pg/mL (normal range, 16–65). He underwent preoperative tumor localization studies. Tc scintigraphy did not show any abnormal tracer uptake. Neck ultrasound identified two large, bilateral, cystic structures in relation to the lower lobes of the thyroid (Figure 1, A and B). Analysis of fluid aspirated from these lesions revealed an extremely high level of PTH ( 5000 pg/mL). The patient underwent neck exploration and removal of bilateral tumors located adjacent to the lower lobes of the thyroid gland and weighing 20 and 2.8 g. The upper parathyroid glands were not enlarged. Histological analysis confirmed cystic parathyroid tumors (Figure 1C). The patient achieved remission postoperatively (serum calcium, 9.52 mg/dL; and PTH, 31 ng/mL). Functional cystic parathyroid tumors are uncommon and occur in only 1–2% of cases of hyperparathyroidism (1). Predominantly cystic multigland disease is exceptionally rare and may not be detected preoperatively. Tumors can be mistaken radiologically for thyroid cysts, but aspiration of the cyst fluid can be useful in confirming their origin (2). Thyroid cyst fluid contains high levels of thyroglobulin, whereas lesions of parathyroid origin have extremely elevated concentrations of PTH. Ultrasound also facilitates the aspiration of cysts with real-time image guidance. This may induce remission of hyperparathyroidism, but relapse is common when cyst fluid accumulates. Injection of ethanol or tetracycline into a functional parathyroid cyst may be curative (3). However, most patients require a parathyroidectomy.

Global Implementation of Computed Tomography Colonography

This chapter is a series of short essays composed by key researchers and advocates of computed tomography colonography from several different countries. I hope this will help document some important historical information regarding the development of computed tomography colonography on a global scale. This information is not available in print in any single source and often incorporates a historical perspective never before appearing in print. Each section has its own style, content, and references. The essays are listed in alphabetical order of the country discussed: Argentina, Austria, Belgium, Canada, France, Germany, Ireland, Israel, Italy, Japan, Korea, Sweden, and the United Kingdom. Authors provided photographs of themselves and/or their research team, which are provided in an appendix at the back of the book.