Heart Transplantation: Indications, Surgical Techniques, and Complications.

Heart transplantation has been increasingly performed for patients with end-stage heart failure most commonly related to ischemic and non-ischemic cardiomyopathies. The major complications are procedure-related complications, infection, acute rejection, cardiac allograft vasculopathy, and malignancy. Radiologists have an important role in the evaluation of transplant candidates and early detection of postoperative complications.

Point Organ Radiation Dose in Abdominal CT: Effect of Patient Off-Centering in an Experimental Human Cadaver Study.

To determine the effect of patient off-centering on point organ radiation dose measurements in a human cadaver scanned with routine abdominal CT protocol. A human cadaver (88 years, body-mass-index 20 kg/m2) was scanned with routine abdominal CT protocol on 128-slice dual source MDCT (Definition Flash, Siemens). A total of 18 scans were performed using two scan protocols (a) 120 kV-200 mAs fixed-mA (CTDIvol 14 mGy) (b) 120 kV-125 ref mAs (7 mGy) with automatic exposure control (AEC, CareDose 4D) at three different positions (a) gantry isocenter, (b) upward off-centering and (c) downward off-centering. Scanning was repeated three times at each position. Six thimble (in liver, stomach, kidney, pancreas, colon and urinary bladder) and four MOSFET dosimeters (on cornea, thyroid, testicle and breast) were placed for calculation of measured point organ doses. Organ dose estimations were retrieved from dose-tracking software (eXposure, Radimetrics). Statistical analysis was performed using analysis of variance. There was a significant difference between the trends of point organ doses with AEC and fixed-mA at all three positions (p < 0.01). Variation in point doses between fixed-mA and AEC protocols were statistically significant across all organs at all Table positions (p < 0.001). There was up to 5-6% decrease in point doses with upward off-centering and in downward off-centering. There were statistical significant differences in point doses from dosimeters and dose-tracking software (mean difference for internal organs, 5-36% for fixed-mA & 7-48% for AEC protocols; p < 0.001; mean difference for surface organs, >92% for both protocols; p < 0.0001). For both protocols, the highest mean difference in point doses was found for stomach and lowest for colon. Measured absorbed point doses in abdominal CT vary with patient-centering in the gantry isocenter. Due to lack of consideration of patient positioning in the dose estimation on automatic software-over estimation of the doses up to 92% was reported.

Improving Concordance of MRI and PET/CT Interpretations With Retrospectively Coregistered MRI and PET/CT Data Sets.

This study evaluates if retrospective software-fused magnetic resonance imaging/positron emission tomography (MRI/PET) images can improve concordance of MRI and PET/computed tomography (CT) findings in the pelvis and improve overall lesion detection and characterization, as compared with independent side-by-side interpretation of MRI and PET data sets. Institutional review board approval was obtained for this retrospective study. Our institution's electronic medical record system was examined for pelvic MRI scans and whole-body (18)F-fluorodeoxyglucose-PET/CT scans performed within a 2-month interval between January 2007 and June 2011. PET and MRI data sets for which there were discordant findings on original clinical reports were fused using software (Siemens TrueD, Erlangen, Germany). The fused MRI/PET data sets were reviewed by 2 radiologists for any evidence of metastatic disease in the pelvis. Interpretations were compared with original PET/CT and MRI reports (interpreted side by side), with pathology and imaging follow-up as the reference standard. Overall, 250 pairs of PET/CT and MRI scans were identified in 228 patients. A total of 57 discordant lesions were identified in 31 pairs of scans (12%) in 31 patients (14%). Software fusion resolved the discordance at 3 sites (5%) among 3 patients (10%), including 2 bone sites and a single nodal site. Software-fused MRI/PET is easy to perform and can increase the concordance rate of PET and MRI findings compared with side-by-side interpretation, thereby improving confidence in lesion characterization.

CT radiation dose and iterative reconstruction techniques.

1. CT radiation dose optimization is one of the major concerns for the scientific community. 2. CT image quality is dependent on the selected image reconstruction algorithm. 3. Iterative reconstruction algorithms have reemerged with the potential of radiation dose optimization by lowering image noise. 4. Tube current is the most common parameter used to reduce radiation dose along with iterative reconstruction. 5. Tube potential (kV) is also used for dose optimization with iterative reconstruction in CT angiography protocols and small patients.

Radiation dose optimization and thoracic computed tomography.

In the past 3 decades, radiation dose from computed tomography (CT) has contributed to an increase in overall radiation exposure to the population. This increase has caused concerns over harmful effects of radiation dose associated with CT in scientific publications as well as in the lay press. To address these concerns, and reduce radiation dose, several strategies to optimize radiation dose have been developed and assessed, including manual or automatic adjustment of scan parameters. This article describes conventional and contemporary techniques to reduce radiation dose associated with chest CT.

Patient communication in radiology: current status of breaking bad news among radiologists and radiology trainees in Pakistan.

Breaking bad news can be an intimidating task for any physician. The aim of this study was to record the practices of breaking bad news to the patients by Pakistani radiologists and trainees. The radiologists and trainees attending the 26th National Radiological Conference in October 2010 in Karachi, Pakistan, were surveyed. The response rate was 76%. The respondents included residents (51%), private practicing radiologists (28%), academic radiologists (13%), and other trainees (8%). Most of the academic radiologists communicated with their patients. The daily frequency of breaking bad news by residents was noted, which was highest in the public teaching hospitals (71%). For severe abnormalities such as malignancy, 50% residents, 55% of the academic radiologists and 74% of the private practicing radiologists were very uncomfortable in disclosure of results. Differences in frequency of communication with patients were noticed with both different training levels, and different settings of practice in a developing country.

Severe combined immune deficiency syndrome.

OBJECTIVE: To determine the clinico-demographic features and laboratory parameters of children with severe combined immunodeficiency (SCID). STUDY DESIGN: Case series. PLACE AND DURATION OF STUDY: Department of Paediatrics and Child Health, the Aga Khan University, Karachi, from July 2006 to July 2011. METHODOLOGY: Thirteen infants who were discharged with a diagnosis of SCID were inducted in the study. Their clinicodemographic features and laboratory parameters were determined. Descriptive statistics has been used for computing frequency and percentage. RESULTS: The median age at diagnosis was five months; 5 infants presented within 3 months of life. Three-fourth (77%) were males. Most of the infants were severely malnourished (85%) at the time of presentation. More than two-thirds (69%) were products of consanguineous marriages. All subjects had severe lymphopenia {absolute lymphocyte count (ALC) ranging between 170 - 2280} and low T and B lymphocyte counts. CONCLUSION: SCID should be considered in infants presenting with severe and recurrent infections. Low ALC (< 2500/mm³), is a reliable diagnostic feature of SCID. These infants should be promptly referred to a facility where stem cell transplant can be done.

Benign granulomatous polyp obstructing the bronchus.

Inflammatory endobronchial polyps are rarely encountered. We report a case of a 14 years old girl with a benign granulomatous polyp originating in the bronchus. Computed tomography scan showed an intraluminal soft tissue opacity while fiberoptic bronchoscopy revealed a large soft tissue mass completely occluding the left lower lobe. Rigid bronchoscopy under general anaesthesia identified a fleshy mass in the left main stem bronchus which was excised via bronchoscopy. The histopathology showed benign polyp with non-specific inflammation. The patient's symptoms improved subsequently and no recurrence was reported till two years of follow-up.