Acute and chronic mesenteric ischemia: MDCT findings / Isquemia mesentérica aguda e crônica: achados tomográficos

Mesenteric ischemia is caused by a reduction in mesenteric blood flow. It can be divided into acute and chronic, based upon the rapidity and the degree to which the blood flow is compromised. The authors retrospectively reviewed 22 cases of mesenteric ischemia, diagnosed by multidetector computed tomography (MDCT) in our service, and confirmed by surgery or clinical follow-up. The frequency of the diagnostic findings of chronic and acute mesenteric ischemia was evaluated. The improvement of three-dimensional (3D) MDCT allows accurate assessment of mesenteric vessels. Therefore, it demonstrates changes in ischemic bowel segments helpful in determining the primary cause of the disease, and can identify the complications in patients with acute and chronic mesenteric ischemia.

A isquemia mesentérica é causada pela redução do fluxo sanguíneo mesentérico. Essa patologia pode ser dividida em aguda e crônica, baseada na rapidez e no grau em que o fluxo sanguíneo está sendo comprometido. Os autores retrospectivamente revisaram 22 casos de isquemia mesentérica, diagnosticados por tomografia computadorizada com mutidetectores (TCMD) em nosso serviço, e confirmados por cirurgia ou seguimento clínico. Os achados diagnósticos de isquemia aguda e crônica e sua frequência foram avaliados. Os avanços na TCMD 3D (tridimensional) permitiram o acesso detalhado aos vasos mesentéricos. Além disso, é possível demonstrar alterações nos segmentos intestinais, auxiliando na identificação da causa primária da doença e podendo identificar as complicações associadas a isquemia mesentérica e crônica.

To code, or not to code?

In summary, it is also important to remember the hidden rules: 1) Just because there is a code in the manual, it doesn't mean it can be billed to insurance, or that once billed, it will be reimbursed. 2) Just because a code was paid once, doesn't mean it will ever be paid again--or that you get to keep the money! 3) The healthcare provider is responsible for knowing all the rules, but then it is impossible to know all the rules! And not knowing all the rules can lead to fines, penalties or worse! New codes are added annually (quarterly for OPPS), definitions of existing codes are changed, and it is the responsibility of healthcare providers to keep abreast of all coding updates and changes. In addition, the federal regulations are constantly updated and changed, making compliant billing a moving target. All healthcare entities should focus on complete documentation, the adherence to authoritative coding guidance and the provision of detailed explanations and specialty education to the payor, as necessary.

Developments in instrumentation for emission computed tomography.

Instrumentation for emission computed tomography continues to evolve, taking advantage of developments in detector technology, data processing and correction methods, and reconstruction algorithms. This article reviews the basic principles and latest developments in emission computed tomography instrumentation, for both positron emission tomography and single-photon emission computed tomography applications.

Implementation of PET scan as a new service.

Positron emission tomography (PET) is a diagnostic test using injected radiopharmaceuticals (drugs or compounds tagged with radioactive isotopes) to obtain images of metabolic/physiologic processes. PET provides physiologic data rather than just anatomic data such as that provided by CT scan or MRI. Metabolic changes precede anatomic changes, hence the higher accuracy of PET. Scar tissue, necrosis and tumor mass may appear identical on CT and MRI, but markedly different on PET. PET may decrease unnecessary surgeries and improve treatment through greater specificity about the disease and may provide a better evaluation of recurrent disease.

Evaluation of a neural-network classifier for PET scans of normal and Alzheimer's disease subjects.

The value of PET as an objective diagnostic tool for dementia may depend on the degree to which abnormal metabolic patterns can be detected by quantitative classification methods. In these studies, a neural-network classifier based on coarse region of interest analyses was used to classify normal and abnormal FDG-PET scans. The performance of neural networks and of an expert reader were evaluated by cross-validation testing. When the "abnormal" class was represented by subjects with clinical diagnoses of "Probable Alzheimer's," the areas under the relative-operating-characteristic (ROC) curves were 0.85 and 0.89 for the neural network and the expert reader, respectively. When testing with abnormal subjects represented by "Possible AD" cases, ROC areas for both the network and the expert were 0.81. The neural network out-performed discriminant analysis. It is concluded that PET has potential for the detection of abnormal brain function in dementing diseases, and that the combination of neural networks and PET is a useful diagnostic tool. Despite the low-resolution "view" afforded the neural network, its performance was nearly equivalent to that of an expert reader.