Hani H. Abujudeh

SPECT brain perfusion abnormalities in mild or moderate traumatic brain injury

The purpose of this atlas is to present a review of the literature showing the advantages of SPECT brain perfusion imaging (BPI) in mild or moderate traumatic brain injury (TBI) over other morphologic imaging modalities such as x-ray CT or MRI. The authors also present the technical recommendations for SPECT brain perfusion currently practiced at their center. For the radiopharmaceutical of choice, a comparison between early and delayed images using Tc-99m HMPAO and Tc-99m ECD showed that Tc-99m HMPAO is more stable in the brain with no washout over time. Therefore, the authors feel that Tc-99m HMPAO is preferable to Tc-99m ECD. Recommendations regarding standardizing intravenous injection, the acquisition, processing parameters, and interpretation of scans using a ten grade color scale, and use of the cerebellum as the reference organ are presented. SPECT images of 228 patients (age range, 11 to 88; mean, 40.8 years) with mild or moderate TBI and no significant medical history that interfered with the results of the SPECT BP were reviewed. The etiology of the trauma was in the following order of frequency: motor vehicle accidents (45%) followed by blow to the head (36%) and a fall (19%). Frequency of the symptoms was headache (60.9%), memory problems (27.6%), dizziness (26.7%), and sleep disorders (8.7%). Comparison between patients imaged early (<3 months) versus those imaged delayed (>3 months) from the time of the accident, showed that early imaging detected more lesions (4.2 abnormal lesions per study compared to 2.7 in those imaged more than 3 months after the accident). Of 41 patients who had mild traumatic injury without loss of consciousness and had normal CT, 28 studies were abnormal. Focal areas of hypoperfusion were seen in 77% (176 patients, 612 lesions) of the group of 228 patients. The sites of abnormalities were in the following order: basal ganglia and thalami, 55.2%, frontal lobes, 23.8%, temporal lobes, 13%, parietal, 3.7%, insular and occipital lobes together, 4.6%.

Incidence of Nephrogenic Systemic Fibrosis after Adoption of Restrictive Gadolinium-based Contrast Agent Guidelines

PURPOSE To retrospectively determine the incidence of nephrogenic systemic fibrosis (NSF) in a large academic medical center after the adoption of restrictive gadolinium-based contrast agent (GBCA) administration guidelines. MATERIALS AND METHODS For this retrospective HIPAA-compliant study, institutional review board approval was obtained and the requirement for informed consent was waived. Restrictive GBCA guidelines were adopted in May 2007. The guidelines (a) require a recent serum creatinine level measurement in any patient who is aged 60 years or older and/or at risk for renal disease, (b) limit the maximal weight-based GBCA dose administered to any patient with an estimated glomerular filtration rate (eGFR) lower than 60 mL/min/m(2) to 20 mL, and (c) prohibit the administration of any GBCA in patients who have an eGFR lower than 30 mL/min/m(2) and/or are undergoing chronic dialysis treatment (except in emergency situations). The electronic medical records were searched for all contrast material-enhanced magnetic resonance (MR) imaging examinations performed during the post-guidelines adoption period between January 2008 and March 2010 and the pre-guidelines adoption and transitional period between January 2002 and December 2007. Separate pathology records were searched for biopsy-confirmed cases of NSF during the same study periods. The incidences of NSF during the pre-guidelines adoption and transitional period and post-guidelines adoption period were compared by using the paired Z test. RESULTS A total of 52,954 contrast-enhanced MR examinations were performed during the post-guidelines adoption period. Of these 52,954 examinations, 46,464 (88%) were performed in adult patients with an eGFR of 60 mL/min/m(2) or higher or presumed normal renal function and 6454 (12%) were performed in patients with an eGFR of 30-59 mL/min/m(2). Thirty-six patients with an eGFR lower than 30 mL/min/m(2) underwent contrast-enhanced MR imaging for emergent indications. Review of the pathology records for January 2008 to September 2010 revealed no new cases of NSF resulting from GBCA exposure. CONCLUSION After restrictive guidelines regarding GBCA administration were instituted, no new cases of NSF were identified among 52,954 contrast-enhanced MR examinations, including those performed in patients with an eGFR lower than 60 mL/min/m(2).

RADPEER scoring white paper.

The ACRs RADPEER program began in 2002; the electronic version, e-RADPEER, was offered in 2005. To date, more than 10,000 radiologists and more than 800 groups are participating in the program. Since the inception of RADPEER, there have been continuing discussions regarding a number of issues, including the scoring system, the subspecialty-specific subcategorization of data collected for each imaging modality, and the validation of interfacility scoring consistency. This white paper reviews the task force discussions, the literature review, and the new recommended scoring process and lexicon for RADPEER.

CT Cystography with Multiplanar Reformation for Suspected Bladder Rupture: Experience in 234 Cases

OBJECTIVE CT cystography has replaced conventional cystography in the evaluation of patients with suspected bladder rupture in most trauma centers. We performed this retrospective review to determine the accuracy of CT cystography and the role of multiplanar reformation in the diagnosis of bladder injury. MATERIALS AND METHODS The patient cohort was composed of trauma patients with clinically or CT-suspected bladder ruptures who were evaluated with CT cystography using two different MDCT scanners at our level 1 trauma center. The patients were identified through Folio, a radiology research tool software system. The CT cystography results were compared with the findings at surgery, clinical follow-up, or both. RESULTS Between January 1, 2000, and December 31, 2004, 234 patients were examined in our level 1 trauma center with CT cystography. From the total of 234 examinations, 216 (92.3%) were interpreted as negative and 18 examinations (7.7%) were interpreted as positive. On the 18 positive examinations, 11 were extraperitoneal bladder rupture, five were intraperitoneal bladder rupture, and two were combined intraperitoneal and extraperitoneal bladder rupture. Surgical bladder exploration and repair were performed in nine of the 18 cases. Seven (77.8%) of the nine cases had operative findings consistent with the CT cystogram findings. The overall sensitivity and specificity of CT cystography in diagnosing bladder rupture were each 100%. For extraperitoneal bladder rupture, the sensitivity and specificity were 92.8% and 100%, respectively. For intraperitoneal rupture, the sensitivity and specificity were 100% and 99%, respectively. CONCLUSION CT cystography is accurate for diagnosing bladder rupture. Sagittal and coronal multiplanar reformations may be helpful in identifying most sites of bladder rupture.

Nephrogenic Systemic Fibrosis after Gadopentetate Dimeglumine Exposure: Case Series of 36 Patients

PURPOSE To retrospectively assess the association between gadopentetate dimeglumine exposure at magnetic resonance imaging and the development of nephrogenic systemic fibrosis (NSF). MATERIALS AND METHODS This HIPAA-compliant study had institutional review board approval. Informed consent was waived. A search of medical and pathologic records was performed to identify patients with NSF that was diagnosed between January 1998 and December 2007. Patients with known exposure to gadolinium-based contrast agents other than gadopentetate dimeglumine were excluded. Medical records were then reviewed for gadopentetate dimeglumine exposure, renal status, concomitant diseases, timing of NSF symptom onset, date of NSF diagnosis, and clinical outcome. Skin gadolinium deposition was assessed for those patients with adequate available tissue. Spearman rank correlations were estimated to assess the relationship between the dose of gadopentetate dimeglumine and the time to onset of NSF. RESULTS Thirty-six patients (mean age, 62.6 years; range, 30-83 years) had been exposed to gadopentetate dimeglumine prior to NSF onset. All had stage 5 chronic kidney disease and all but one were undergoing dialysis at the time of exposure. NSF developed within 3 months after the last gadopentetate dimeglumine exposure (range, 1-59 months) in 21 (66%) of 32 patients. The patients had been exposed to median cumulative gadopentetate dimeglumine volumes of 35, 40, 85, and 117.5 mL over the 3, 12, and 24 months and up to 11 years preceding the onset of NSF, respectively. Patients who received higher cumulative and total gadopentetate dimeglumine doses had a higher risk of developing NSF than did those who received lower doses (odds ratio = 1.2). Twenty (56%) of 36 patients died, with a median interval of 18 months between NSF symptom onset and death. CONCLUSION NSF develops in patients with renal impairment after exposure to gadopentetate dimeglumine in a dose- and time-dependent manner. SUPPLEMENTAL MATERIAL http://radiology.rsna.org/lookup/suppl/doi:10.1148/radiol.2531082160/-/DC1.

Nephrogenic Systemic Fibrosis

OBJECTIVE The purpose of this article is to discuss nephrogenic systemic fibrosis (NSF) in detail regarding its history, possible pathophysiology, clinical and pathologic presentations, diagnosis, and implications for the radiology community. CONCLUSION NSF is a potentially lethal disorder that occurs in patients with reduced kidney function. Current evidence suggests a strong association with gadolinium-based contrast agents--mostly used in MRI--in this patient group. This has urged the radiology community to emphasize careful screening for the presence of renal dysfunction among patients for whom gadolinium-enhanced MRI is contemplated. Appropriate selection of gadolinium-based contrast agent type, avoidance of nonstandard dosage, patient education, and informed consent have been recommended by authorities.

Acute Adverse Reactions to Gadopentetate Dimeglumine and Gadobenate Dimeglumine: Experience With 32,659 Injections

OBJECTIVE The purpose of this study was to retrospectively assess the frequency, manifestations, and severity of acute adverse reactions associated with administration of two gadolinium-based contrast agents to patients who underwent MRI at a single large academic institution. MATERIALS AND METHODS Data from continuous quality assurance records on the number of administrations of and acute adverse reactions to gadopentetate dimeglumine and gadobenate dimeglumine at our institution October 2007 to December 2008 were tabulated and analyzed. During the investigation period, 32,659 administrations of gadolinium-based contrast agents were performed for MRI examinations. Of these, 27,956 administrations were gadopentetate dimeglumine, and 4,703 administrations were gadobenate dimeglumine. Data were collected on the frequency and severity of acute adverse reactions. RESULTS A total of 51 acute adverse reactions occurred in 50 patients (16 men, 34 women; mean age, 48 years), accounting for 0.16% of all administrations (51/32,659). Thirty-eight reactions (38/27,956, 0.14%) were associated with gadopentetate dimeglumine, and 13 (13/4,703, 0.28%) were associated with gadobenate dimeglumine. Forty-three reactions were mild, six were moderate, and two were severe. The severe reactions occurred with the use of gadobenate dimeglumine. CONCLUSION The rates of acute adverse reactions to gadopentetate dimeglumine and gadobenate dimeglumine were 0.14% and 0.28%, respectively. The overall adverse reaction rate was 0.16% in our patient sample. Direct comparison of adverse reaction rates of the two agents was not possible because of the retrospective uncontrolled study design.

Current status of nephrogenic systemic fibrosis

Nephrogenic systemic fibrosis (NSF) occurs in patients with advanced chronic kidney disease (CKD) or acute renal failure, most commonly following exposure to gadolinium-based contrast agents (GBCAs). NSF can be debilitating and associated with increased mortality. The putative association of NSF with GBCAs prompted the development of guidelines to limit the use of these contrast agents in at-risk patients. Indeed, the incidence of NSF has decreased dramatically following application of these guidelines, which appears to be the only effective means of decreasing NSF incidence. Thus, increasing clinician awareness of these updated guidelines is important. The present review introduces and compares updated guidelines for GBCA use and discusses the latest advances in the understanding of the pathogenic mechanisms and treatment of NSF.

SPET brain perfusion imaging in mild traumatic brain injury without loss of consciousness and normal computed tomography.

We present SPET brain perfusion findings in 32 patients who suffered mild traumatic brain injury without loss of consciousness and normal computed tomography. None of the patients had previous traumatic brain injury, CVA, HIV, psychiatric disorders or a history of alcohol or drug abuse. Their ages ranged from 11 to 61 years (mean = 42). The study was performed in 20 patients (62%) within 3 months of the date of injury and in 12 (38%) patients more than 3 months post-injury. Nineteen patients (60%) were involved in a motor vehicle accident, 10 patients (31%) sustained a fall and three patients (9%) received a blow to the head. The most common complaints were headaches in 26 patients (81%), memory deficits in 15 (47%), dizziness in 13 (41%) and sleep disorders in eight (25%). The studies were acquired approximately 2 h after an intravenous injection of 740 MBq (20.0 mCi) of 99Tcm-HMPAO. All images were acquired on a triple-headed gamma camera. The data were displayed on a 10-grade colour scale, with 2-pixel thickness (7.4 mm), and were reviewed blind to the patients history of symptoms. The cerebellum was used as the reference site (100% maximum value). Any decrease in cerebral perfusion in the cortex or basal ganglia less than 70%, or less than 50% in the medial temporal lobe, compared to the cerebellar reference was considered abnormal. The results show that 13 (41%) had normal studies and 19 (59%) were abnormal (13 studies performed within 3 months of the date of injury and six studies performed more than 3 months post-injury). Analysis of the abnormal studies revealed that 17 showed 48 focal lesions and two showed diffuse supratentorial hypoperfusion (one from each of the early and delayed imaging groups). The 12 abnormal studies performed early had 37 focal lesions and averaged 3.1 lesions per patient, whereas there was a reduction to--an average of 2.2 lesions per patient in the five studies (total 11 lesions) performed more than 3 months post-injury. In the 17 abnormal studies with focal lesions, the following regions were involved in descending frequency: frontal lobes 58%, basal ganglia and thalami 47%, temporal lobes 26% and parietal lobes 16%. We conclude that: (1) SPET brain perfusion imaging is valuable and sensitive for the evaluation of cerebral perfusion changes following mild traumatic brain injury; (2) these changes can occur without loss of consciousness; (3) SPET brain perfusion imaging is more sensitive than computed tomography in detecting brain lesions; and (4) the changes may explain a neurological component of the patients symptoms in the absence of morphological abnormalities using other imaging modalities.

Pulmonary Embolism and Deep Venous Thrombosis in Trauma: Are They Related?

HYPOTHESIS Pulmonary embolism (PE) and deep venous thrombosis (DVT) in trauma are related. DESIGN Retrospective review of medical records. SETTING Academic level I trauma center. PATIENTS Trauma patients who underwent computed tomographic pulmonary angiography (CTPA) with computed tomographic venography (CTV) of the pelvic and proximal lower extremity veins over a 3-year period (January 1, 2004, to December 31, 2006) were reviewed. Data on demographics, injury type and severity, imaging findings, hospital length of stay, and mortality were collected. MAIN OUTCOME MEASURES Pulmonary embolism and DVT. RESULTS Among 247 trauma patients undergoing CTPA/CTV, PE was diagnosed in 46 (19%) and DVT in 18 (7%). Eighteen PEs were central (main or lobar pulmonary arteries), and 28 PEs were peripheral (segmental or subsegmental branches). Pulmonary embolism occurred within the first week of injury in two-thirds of patients. Seven patients with PE (4 femoral, 2 popliteal, and 1 iliac) had DVT. Pulmonary embolism was central in 5 patients and peripheral in 2 patients. No significant differences were noted in any of the examined variables between patients with PE having DVT and those not having DVT. CONCLUSIONS Few patients with PE have DVT of the pelvic or proximal lower extremity veins. Pulmonary embolism may not originate from these veins, as commonly believed, but instead may occur de novo in the lungs. These findings have implications for thromboprophylaxis and, particularly, the value of vena cava filters.